- Innovative waveguide technology enables remotely deployed, precise 360-degree inspection, making previously inaccessible areas fully inspectable in hazardous industrial environments -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho-seong) has developed an ultrasonic sensor technology that applies a waveguide* to detect defects in all directions without directly attaching sensors to the inspection target.

By enabling remote ultrasonic excitation and reception, the technology is expected to help prevent industrial accidents and eliminate inspection blind spots in high-risk industrial facilities where direct sensor installation has been challenging due to heat, toxic gases, or other hazardous environmental conditions.

 * Waveguide: A tubular structure designed to guide waves or physical energy along a defined path. Depending on its geometry, a waveguide can control ultrasonic propagation direction, manage reflection and refraction phenomena, and optimize the directionality and energy efficiency of transmitted waves.

▲ Researchers from the Non-Destructive Metrology Group at KRISS

(From left to right: Kim Seung Il (Department of Precision Measurement Engineering, University of Science and Technology, UST);

Jeong Ju Young (Department of Mechanical Engineering, Yonsei University, YU);

Dr. Seung Hong Min (Non-Destructive Metrology Group, KRISS);

Dr. Park Chan Wook (Postdoctoral Researcher, Non-Destructive Metrology Group, KRISS);

Dr. Park Choon-Su (Head of the Non-Destructive Metrology Group, KRISS))

Non-Destructive Testing (NDT) is a safety inspection technique that uses ultrasonic signals to detect internal defects without damaging the structure under examination. It is regarded as a critical technology for ensuring structural reliability in safety-critical industries such as aerospace, nuclear power, and large-scale industrial plants.

However, conventional ultrasonic sensors for NDT have been difficult to deploy in extreme environments, such as high-temperature piping in nuclear power plants or storage facilities containing hazardous chemicals. Because these sensors must be directly attached to the surface of the inspection target, they are frequently damaged by intense heat or corrosive substances. In addition, in restricted high-risk areas where human access is limited, sensor installation itself is often impossible.

Conventional ultrasonic transducers designed for full 360-degree inspection have typically relied on segmented configurations, in which multiple sensing elements are arranged circumferentially. However, combining wave signals from these segmented sources often leads to interference and distortion, reducing inspection accuracy.

▲ Schematic diagram of the waveguide-based omnidirectional ultrasonic sensor developed by KRISS

To overcome this limitation, the KRISS Non-Destructive Metrology Group introduced a waveguide as an intermediate medium. By transmitting ultrasonic waves through the waveguide, the sensing region can be installed remotely without direct contact with the surface under inspection. This approach enabled the development of a new type of ultrasonic sensor capable of operating under high-risk conditions while maintaining precise defect detection performance.

The core innovation lies in generating torsional vibration within a cylindrical waveguide—much like twisting a towel—and then uniformly transferring this vibration to the surface under inspection. Through this mechanism, ultrasonic waves propagate evenly in all directions, enabling precise defect detection even when the sensor is installed at a distance from the target structure. Notably, the waveguide can be fabricated using various materials and geometries, and its end can be machined to conform to curved structural surfaces. This flexibility allows stable operation under diverse environmental conditions and on complex structural shapes.

▲ Omnidirectional SH Wave Transducers and Deformation Sources: (a) Conventional Approaches vs. (b) Proposed Waveguide-based Method

Experimental results demonstrated that the developed sensor achieved approximately 95% directional uniformity and high-purity wave propagation, enabling consistent signal capture across the entire inspection range. Signal amplitude was also improved by more than 13.7 times compared to conventional segmented configurations, allowing rapid scanning of wide areas and high-resolution imaging.

This technology is expected to enable real-time monitoring of structures in extreme environments where conventional NDT methods have been impractical, significantly enhancing industrial safety. In addition, by replacing multiple high-cost sensors with a single sensor integrated with a low-cost waveguide structure, the system can inspect large areas efficiently while substantially reducing inspection costs.

Dr. Seung Hong Min of the Non-Destructive Metrology Group at KRISS said the newly developed sensor also demonstrates excellent signal performance in liquid environments, enabling precise inspection of large submerged structures. "Based on its high reliability and versatility, the technology can be readily applied to accident prevention systems across various industrial facilities. By detecting previously inaccessible inspection blind spots, it has the potential to significantly contribute to the prevention of large-scale industrial disasters," he added.

This research was supported by the KRISS Basic Research Program and was published in December in Mechanical Systems and Signal Processing (Impact Factor: 8.9), a leading international journal in the field of mechanical engineering.

Enhances Multi-Gas Detection

- KRISS develops a low-power sensor capable of selectively identifying multiple hazardous gases for industrial and everyday safety applications. -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a next-generation gas sensor technology that uses low-cost and safe LED light to precisely distinguish multiple hazardous gases. Compared with conventional sensors that operate at high temperatures, the new technology consumes significantly less power, offering greater cost efficiency while delivering broad applicability. It is expected to enhance gas safety across industrial settings as well as everyday environments.

▲ (Pic 1) LED-based multi-gas selective sensor developed by KRISS

Gas sensors currently used in industrial settings typically operate in a high-temperature mode, maintaining temperatures of 200–400°C to enhance reactivity with gas molecules. This approach requires each sensor to be equipped with a micro-heater that continuously heats the device, resulting in high power consumption. Repeated exposure to elevated temperatures also accelerates material degradation, shortening the sensor's operational lifespan.

To address these limitations, gas sensors incorporating ultraviolet (UV) or visible-light LED panels instead of heaters have been proposed. However, commercialization has been constrained by safety and performance concerns. While UV-based sensors offer strong gas reactivity, they pose potential risks of skin damage upon human exposure. In contrast, visible-light LED sensors are safer but exhibit weaker reactivity with gas molecules, making it difficult to detect gases other than nitrogen dioxide.

Dr. Kwon Ki Chang, Principal Research Scientist of the Emerging Material Metrology Group at KRISS, and Nam Gi Baek, a Ph.D. student in the Department of Materials Science and Engineering at Seoul National University, developed a nanostructure in which indium sulfide (In2S3) is thinly coated onto indium oxide (In2O3), dramatically enhancing the performance of visible-light LED-based gas sensors.

The nanostructure, designed in a Type-I heterojunction configuration, acts as an "energy well" that prevents photo-generated charge carriers from dispersing outward and instead concentrates them at the reactive surface when exposed to light. By maximizing the efficiency of light energy utilization, the structure enables immediate interaction with gas molecules using only blue LED illumination without the need for an external heat source.

▲ (Pic 2) Schematic illustration of the LED-based multi-gas selective sensor developed by KRISS

The research team implemented an electronic nose (E-nose) system by arranging sensors coated with platinum (Pt), palladium (Pd), and gold (Au) nanoparticles on the developed heterojunction structure. Each noble metal catalyst was engineered to respond selectively to specific gases, enabling the system to clearly distinguish hazardous gases such as hydrogen, ammonia, and ethanol even in mixed gas environments much like the human sense of smell.

Performance tests demonstrated that the sensor achieved a limit of detection (LOD) of 201.03 parts per trillion (ppt), representing approximately a 56-fold improvement in sensitivity compared to conventional LED-based sensors. The device also maintained stable operation under 80% humidity and preserved its initial performance over long-term evaluations exceeding 300 days, confirming its strong durability.

▲ (Pic 3) Research team behind the development of the LED-based multi-gas selective sensor

The new technology enables a single sensor to identify multiple types of gases while consuming minimal power, making it economically viable for both industrial applications and household use. By detecting various hazardous gases simultaneously with a single installation, it can significantly reduce the cost of sensor deployment in factories and power plants. Thanks to its low maintenance costs, the technology can be readily adopted for real-time air quality monitoring in residential facilities and public spaces.

The sensor operates at room temperature without the need for high-temperature heating, making it well suited for integration into wearable devices such as smartphones and smartwatches. Upon commercialization, the technology could enable user-centered safety services that allow individuals to monitor hazardous environmental conditions in real time along their daily routes and respond immediately to potential gas leak incidents.

Dr. Kwon Ki Chang said the team plans to further optimize catalyst combinations to develop customized intelligent sensors capable of selectively detecting hazardous gases tailored to specific site conditions.

This research was supported by the Nano and Materials Technology Development Program of the Ministry of Science and ICT and was published in December in Small (Impact Factor: 12.1), a leading journal in the fields of nanotechnology and sensor research.

- KRISS develops innovative diatomaceous earth powder certified reference material to eliminate measurement bias in environmental monitoring. -

A team of Korean researchers has developed a reference material that significantly improves the accuracy of analyzing hexavalent chromium, a Group 1 carcinogen that can be present in groundwater and soil.

▲ Certified reference material (CRM) of diatomaceous earth powder for hexavalent chromium analysis 

(KRISS CRM 106-01-001, batch no. 12411).

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has collaborated with the Pohang Accelerator Laboratory (PAL, Acting Director Park Jaehun) to develop a diatomite-based Certified Reference Material (CRM) that enables accurate measurement of hexavalent chromium concentrations in environmental samples. This CRM is the first in the world to apply synchrotron-based X-ray absorption spectroscopy (XAS) to analyze hexavalent chromium in environmental samples without the need for sample pre-treatment, a key innovation that ensures accurate measurements and eliminates species transformation that could otherwise lead to biased results. The new CRM is expected to enhance the accuracy and reliability of hazardous substance testing by providing an objective benchmark for evaluating and calibrating measurement results produced by environmental analysis laboratories.

Hexavalent chromium, due to its strong toxicity and oxidizing properties, is classified as a Group 1 carcinogen by the International Agency for Research on Cancer (IARC) under the World Health Organization (WHO). It can be found not only at industrial facilities but also in everyday environments, such as drinking groundwater and sand in public playgrounds. Accordingly, Korea strictly regulates and monitors the presence of hexavalent chromium in groundwater, soil, and living environments under its environmental management laws.

However, despite variations in measurement results among environmental testing laboratories, there has been no adequately standardized reference to objectively verify and calibrate hexavalent chromium analyses, limiting improvements in the accuracy and consistency of test results.

▲ Research team behind the development of the diatomaceous earth powder CRM for hexavalent chromium analysis.

 (From the front row, clockwise) Dr. Cho Hana (KRISS, Principal Research Scientist), Kong Gi Won (PAL, Engineer), Dr. Heo Sung Woo (KRISS, Head of the Inorganic Metrology Group), 

Lim Youngran (KRISS, Senior Engineer), Hong Sangyeob (KRISS, Senior Engineer), and Dr. Choi Sun Hee (PAL, Principal Research Scientist).

A research team led by Dr. Cho Hana of the Inorganic Metrology Group at KRISS collaborated with a team led by Dr. Choi Sun Hee of the PLS-II 7D beamline at PAL to successfully develop a diatomaceous earth (diatomite) powder CRM for hexavalent chromium analysis. This CRM serves as a reference material used to verify the accuracy of measurement results and analytical methods—often likened to an answer key for analytical testing. By using a CRM, analytical laboratories can independently validate the performance of their measurement instruments and the validity of their analytical procedures, thereby ensuring the reliability of measurement data.

The development of a CRM for hexavalent chromium analysis has long been challenging due to species transformation that occurs during the measurement process, making accurate quantification fundamentally difficult. Conventional wet analysis methods require solid samples to be dissolved during a pretreatment step, during which hexavalent chromium can be converted to other oxidation states or measured at concentrations lower than their true values.

▲ Manufacturing process of the diatomaceous earth powder CRM for hexavalent chromium analysis. 

KRISS addressed this challenge by becoming the first in the world to apply XAS to the development of an environmental CRM for hexavalent chromium analysis. Using synchrotron radiation that is hundreds of millions of times brighter than sunlight, the joint research team successfully captured the characteristic energy absorption signals of hexavalent chromium without destroying the sample. This approach fundamentally eliminated systematic errors arising from pretreatment processes and enabled correction of even subtle measurement biases in the data. Similar to MRI, the newly adopted non-destructive analytical method secured both the accuracy and reliability required for CRM development.

This CRM is expected to improve the accuracy, traceability, and reliability of groundwater and soil contamination monitoring, providing a stronger foundation for the credibility of national environmental policies. It is also anticipated to enhance the analytical reliability and competitiveness of Korean export-oriented companies that must comply with global environmental regulations, including the European Union’s Restriction of Hazardous Substances (RoHS) directive.

Dr. Heo Sung Woo, Head of the Inorganic Metrology Group at KRISS, said the joint research represents a novel application of synchrotron-based techniques to research on measurement standards, overcoming the limitations of conventional analytical methods. He added that the newly developed CRM, with its accuracy and reliability ensured through the new approach, is expected to become an essential reference for environmental analysis.

The newly developed CRM is available for purchase through KRISS Measurement Standards Services, the institute’s official platform for certified reference materials (https://eshop.kriss.re.kr).

- KRISS exports primary radioactivity measurement standards to Thailand, reinforcing Korea's leadership in radiation measurement across the Asia–Pacific region -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has successfully exported its proprietary radioactivity measurement standard to Thailand. This milestone marks a significant step in establishing South Korea's metrology technology as a benchmark for radiation safety management across the Asia-Pacific region.

▲ Group photo of the KRISS Radioactivity Group and officials from Thailand’s Office of Atoms for Peace (OAP)

KRISS finalized an agreement with Thailand's Office of Atoms for Peace (OAP) to export its "Primary Standard for the Measurement of Alpha and Beta Particle Surface Emission Rate" and successfully completed on-site system installation, as well as the transfer of related technical expertise.

The exported system is the ultimate reference for ensuring the reliability of surface contamination monitors. These monitors are essential in medical, research, and industrial settings to detect radioactive contamination on personnel, equipment, and environments. To remain accurate, these devices must undergo periodic calibration using "area sources"—reference materials with precisely verified radiation emission rates. KRISS's primary standard serves as the core infrastructure that validates the absolute accuracy of these area sources.

▲ The Primary Standard for the Measurement of Alpha and Beta particle Surface Emission Rate exported by KRISS to Thailand's Office of Atoms for Peace (OAP)

Developed by the KRISS Radioactivity Group, the system boasts a world-class measurement uncertainty of less than 1%. This performance was made possible by the integration of a windowless Multi-Wire Proportional Counter (MWPC) that eliminates measurement loss from detector covers, along with an advanced signal-processing system that ensures both device miniaturization and high-sensitivity performance by minimizing noise.

* A multi-wire proportional counter is a highly sensitive radiation detector in which multiple fine wires are arranged inside a gas-filled chamber to amplify and measure electrical signals generated as radiation passes through.

Following its export of the system to the National Metrology Institute of South Africa in 2016, KRISS has now succeeded in exporting the technology to the Asian region as well, further demonstrating its world-class capabilities in radioactivity measurement. In particular, this achievement is significant in that it lays the groundwork for South Korea’s radioactivity measurement technology to be operated as a regional standard across the Asia–Pacific region.

▲ A KRISS researcher utilizes the primary measurement standard to determine the surface emission rate of an area source

"As Thailand utilizes this system to participate in Key Comparisons (KC) and gains international recognition for its measurement reliability, South Korea's technical standing will reach new heights," said Dr. Kim Byoung-Chul, Head of the Radioactivity Group at KRISS. "We will leverage this achievement to continuously expand our export channels across various ASEAN nations."

- KRISS develops a cost-cutting materials technology that reduces oxide-based solid electrolyte production costs by over 90%, enabling low-cost, large-scale manufacturing -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a key materials technology that accelerates the commercialization of all-solid-state batteries (ASSBs)—next-generation batteries designed to intrinsically eliminate the risks of fire and explosion.

The Emerging Material Metrology Group at KRISS demonstrated ultra-dense, large-area solid electrolyte membranes by applying a method that coats solid electrolyte powders with multifunctional compounds, reducing production costs to one-tenth of conventional levels.

▲ (Pic 1) Research team behind the development of key materials technology for oxide-based solid electrolyte membranes

(From left) Dr. Baek Seung-Wook, Principal Research Scientist, Emerging Material Metrology Group, KRISS; Choi Minseo, Student Researcher; 

Dr. Kim Hwa-Jung, Postdoctoral Researcher, KRISS; Professor Park Hyeokjun, Department of Materials Science and Engineering, Korea University

Lithium-ion secondary batteries, which are widely used in electric vehicles (EVs) and energy storage systems (ESS), rely on flammable liquid electrolytes, making them vulnerable to fires and explosions. Once ignited, such fires are particularly difficult to extinguish. In recent years, a series of incidents—including a fire at a government data center operated by the National Information Resources Service (NIRS) and explosions involving EV batteries—has further underscored the urgent need for safer lithium battery technologies.

All-solid-state batteries (ASSBs) replace liquid electrolytes with non-flammable solid electrolytes, fundamentally improving battery safety. Among them, oxide-based all-solid-state batteries have attracted significant attention as a promising next-generation solution due to their high energy density and the absence of risks associated with toxic gas release, which can occur in sulfide-based systems.

Oxide-based all-solid-state batteries primarily employ garnet-type solid electrolytes as their core materials. Garnet-type solid electrolytes exhibit high ionic conductivity and excellent chemical stability; however, due to their intrinsic material properties, the fabrication of high-performance electrolyte membranes requires a high-temperature sintering process, in which the powder is compacted at temperatures exceeding 1,000 °C.

A major challenge during this sintering process is the evaporation of lithium, a key constituent of the solid electrolyte membrane. Lithium loss compromises the structural stability of the electrolyte, making large-area fabrication difficult, and leads to significant degradation in material quality, including reduced ionic conductivity and increased interfacial resistance, due to changes in chemical composition.

To mitigate lithium evaporation, conventional approaches have relied on covering the electrolyte membrane with a large quantity of mother powder—a lithium-containing electrolyte material—during sintering. However, this method results in more than ten times the amount of mother powder being discarded compared to the actual electrolyte membrane produced, significantly increasing production costs and posing a major barrier to commercialization.

▲ (Pic 2) Schematic illustration of the high-performance, large-area solid electrolyte fabrication process developed by KRISS

The research team fully addressed this challenge by developing a fabrication technique that thinly coats solid electrolyte powders with Li–Al–O–based (lithium–aluminum–oxide) multifunctional compounds.

The resulting surface coating layer supplies lithium during the sintering process while preventing lithium evaporation, and simultaneously enhances interparticle bonding through a soldering-like effect, thereby maximizing the densification of the electrolyte membrane.

▲ (Pic 3) Key performance evaluation results of solid electrolytes to which the KRISS-developed process technology was applied

Using this approach, the team achieved a record-high density exceeding 98.2% without employing any expensive mother powder, producing high-strength solid electrolyte membranes free from chemical and mechanical defects, with ionic conductivity improved by more than twofold compared to conventional materials.

In addition, the electronic conductivity of the solid electrolyte membrane was reduced by more than 20 times, significantly lowering the risk of internal current leakage and thereby enhancing both the efficiency and safety of all-solid-state batteries.

Notably, the research team successfully fabricated large-area solid electrolyte membranes with an area of 16 cm²—more than ten times larger than conventional laboratory-scale pellets—while achieving an exceptional yield of 99.9%.

Dr. Baek Seung-Wook, Principal Research Scientist of the Emerging Material Metrology Group at KRISS, stated,

"This achievement fully resolves long-standing materials and manufacturing challenges that have remained unsolved for more than two decades in garnet-type solid electrolyte research. By dramatically reducing production costs, our technology is expected to significantly accelerate the commercialization of oxide-based all-solid-state batteries and drive technological innovation in the energy storage systems (ESS) and electric vehicle markets."

Dr. Kim Hwa-Jung, a Postdoctoral Researcher in the Emerging Material Metrology Group at KRISS, noted,

"At present, Korea relies entirely on imports for garnet-type solid electrolyte pellets, which cost more than USD 550 per unit for a diameter of just 1 cm. This technological breakthrough is expected to open the door to domestic production of high-value next-generation battery materials."

This research was conducted in collaboration with Professor Park Hyeokjun’s team from the Department of Materials Science and Engineering at Korea University. The work was supported by the Ministry of Science and ICT and the National Research Foundation of Korea (NRF) under the Nano and Materials Technology Development Program, and was published in the January issue of Materials Today (Impact Factor: 22.0; JCR top 3.5%).

- A KRISS-developed calibration test method for radiosonde temperature sensors establishes a unified international benchmark for upper-air measurements. -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has succeeded in having its radiosonde performance evaluation technology—used for one of the key instruments in weather and climate observation—adopted as an international standard.

* A radiosonde is an atmospheric observation instrument suspended from a large balloon and launched to altitudes of approximately 35 km to measure meteorological parameters such as temperature, humidity, and pressure. It consists of temperature and humidity sensors and a radio transmitter.

The radiosonde temperature sensor calibration test method, jointly developed by the Thermometry and Fluid Flow Metrology Group at KRISS in collaboration with Weathex Co., Ltd., the Korea Meteorological Administration (KMA), and the Korea Meteorological Institute (KMI), has been adopted as an international standard in meteorology (ISO 8932-1). This marks the first establishment of an international benchmark for accurately evaluating and calibrating radiosonde temperature sensors and is expected to significantly enhance the accuracy of weather forecasting and global climate prediction worldwide.

▲ (Pic 1) KRISS Thermometry and Fluid Flow Metrology Group

(Front row, from left) Dr. Lee Sang-Wook (Principal Research Scientist), Dr. Kim Seonwoong (Senior Research Scientist), Kim Sunghun (Senior Engineer), 

Lee Young-Suk (Senior Engineer), Dr. Kim Yong-Gyoo (Principal Research Scientist)

Air temperature is a primary indicator that most directly reflects climate change. Short-term weather forecasts, which people encounter in daily life, primarily rely on temperature data from the troposphere, where air circulation is highly active. In contrast, long-term climate change observations depend on temperature measurements in the stratosphere, a region characterized by relatively stable air and limited atmospheric motion. To improve the accuracy of climate change predictions, it is therefore essential to continuously and precisely measure subtle temperature variations in the stratosphere.

Radiosondes are the primary instruments used to measure temperatures in the stratosphere. Today, meteorological agencies around the world rely on radiosondes for upper-air weather and climate observations. In particular, the sensors of a radiosonde—which directly interact with the surrounding atmosphere—are critical components that determine overall measurement performance. Because the upper atmosphere is strongly influenced by solar radiation and high-altitude winds, regular calibration of these sensors is essential to maintain measurement accuracy.

However, until now, there had been no internationally recognized standards or procedures for objectively evaluating the performance of radiosonde sensors. As a result, radiosonde users were forced to rely on performance specifications provided by manufacturers, making it difficult to independently verify sensor performance and limiting the reliability of upper-air meteorological observation data.

The ISO 8932-1 test method, newly approved as an international standard, defines detailed criteria and procedures for calibrating the measurement errors of radiosonde temperature sensors under upper-atmospheric conditions. Using this method, calibration errors can be maintained within 0.1 °C even in environments reaching altitudes of up to 40 km and temperatures as low as –85 °C.

▲ (Pic 2) Cover page of ISO 8932-1, the newly adopted international standard for radiosonde temperature sensor calibration test methods

▲ (Pic 3) (Left) Upper Air Simulator (UAS) installed at the meteorological instrument verification and certification facility in Ochang, operated by the Korea Meteorological Institute (KMI)/ 

(Right) Temperature sensor evaluation chamber for radiosondes inside the Upper Air Simulator (UAS)

The international standard is based on KRISS's proprietary calibration technology for radiosonde temperature sensors and was finalized following a comprehensive review by an ISO working group (ISO WG) comprising meteorological and climate experts as well as manufacturers from multiple countries. In 2019, KRISS independently developed an Upper Air Simulator (UAS) capable of reproducing key atmospheric parameters—including temperature, humidity, pressure, solar radiation, and wind speed—under controlled laboratory conditions. Leveraging this system, KRISS has since established advanced techniques for high-precision calibration of radiosonde temperature sensors across a wide range of atmospheric environments.

With the establishment of an internationally recognized test method, the accuracy of upper-air meteorological observation data is expected to improve significantly. Radiosonde manufacturers will be able to evaluate and refine product performance at the development stage, while national meteorological agencies can verify radiosonde performance against objective criteria, ensuring more accurate and reliable weather information.

Dr. Kim Yong-Gyoo stated,

"The establishment of this international standard will enable countries worldwide to secure more reliable meteorological observation data, and is expected to contribute to the development of more sophisticated global climate prediction models."

This research was supported by the KRISS Basic Research Program and the National Standards Technology Advancement Program funded by the Ministry of Trade, Industry and Resources (MOTIR).

Accelerating the "Energy Highway"

- New 600–800 kV standards allow rapid in-country calibration, eliminating foreign dependence and strengthening Korea's competitiveness in next-generation power grids -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has established Korea's first national standards for the reliable performance verification of High Voltage Direct Current (HVDC)* transmission systems. Based on these newly established standards, KRISS will begin providing calibration and testing services for national power authorities and related industries.

* High Voltage Direct Current (HVDC): A transmission technology that delivers electric power in the form of high-voltage direct current, suitable for long-distance and large-capacity power delivery. In general, transmission efficiency increases with higher voltage. Voltage levels are typically classified as 30–220 kV for high voltage (HV), 300–1000 kV for extra-high voltage (EHV), and above 1000 kV for ultra-high voltage (UHV).

▲ KRISS researchers operating a DC ultra-high-voltage divider for HVDC voltage measurement

KRISS has now established measurement standards for 600-kV-class high-voltage DC, 800-kV lightning impulse, and 700-kV switching impulse measurements. With these standards in place, Korea now has a reliable basis for accurately evaluating and improving the performance of ultra-high-voltage power equipment—an advancement expected to strengthen the manufacturing quality and export competitiveness of domestic heavy electrical equipment companies.

* Heavy electrical equipment: A general term for facilities, systems, and components used to generate, transmit, and utilize electric power. Most power infrastructure—such as power transformers, cables, switchgear, and circuit breakers—falls under this category.

HVDC is a transmission technology that converts alternating current from power plants into ultra-high-voltage direct current. Compared with conventional AC transmission, HVDC offers significantly lower power losses and allows easier control of power flow, making it highly advantageous for long-distance and large-capacity transmission. Because of these characteristics, HVDC is emerging as a next-generation transmission solution for delivering electricity produced in non-metropolitan regions to the high-demand metropolitan area in a stable and efficient manner. At the first meeting of the National Power Grid Committee held in October, the Korean government identified HVDC industry development as a core strategy for building the nation's "energy superhighway."

According to growing market demand, Korean manufacturers have also accelerated the development of HVDC equipment. However, until now, the absence of national measurement standards for ultra-high-voltage testing has made it difficult for companies to certify product performance or advance into global markets. All heavy electrical equipment used in HVDC systems must pass performance tests specified by the International Electrotechnical Commission (IEC). But because Korea had no domestic measurement standards to objectively measure such performance, companies had no choice but to rely on overseas calibration bodies to conduct the required tests.

▲ Evaluation of the ultra-high-voltage DC standard system and on-site calibration of an HVDC generator

To address these challenges, the Quantum Electricity and Magnetism Metrology Group at KRISS has established new ultra-high-voltage measurement standards tailored for HVDC equipment. KRISS first expanded its previous DC high-voltage standard—from the 200-kV level to a 600-kV-class standard, tripling the available measurement range. This standard serves as the reference for withstand voltage tests, which evaluate whether power equipment can remain stable under voltages higher than normal operating conditions for a specified duration.

KRISS has also established new measurement standards for 800-kV lightning impulse (LI) and 700-kV switching impulse (SI) testing. Lightning impulses simulate the extremely high voltages generated when a lightning strike induces a sudden surge of current, while switching impulses replicate the transient overvoltages that occur when large power equipment is turned on or off. These two standards provide the basis for impulse voltage testing, which evaluates the insulation performance of power equipment under extreme high-voltage conditions that occur within a very short duration.

With the establishment of these standards, Korea now has a system that enables the testing and calibration of ultra-high-voltage equipment in accordance with IEC international specifications. This allows companies to conduct tests quickly and at their desired schedule, helping shorten the time required for product commercialization and enabling faster responses to market demand.

▲ Quantum Electricity and Magnetism Metrology Group at KRISS

(From left: Dr. Lee Hyung Kew, Head of the Group; Lee Sang Hwa, Senior Engineer)

Dr. Lee Hyung Kew, Head of the Quantum Electricity and Magnetism Metrology Group at KRISS, stated, "Based on the newly established standards, KRISS has begun providing calibration services for HVDC testing equipment at KEPCO's Gochang Electric Power Testing Center and at ILJIN Electric. We will continue to develop the ultra-high-voltage measurement standards needed by Korea's power industry, contributing to the stability of the national grid and to strengthening industrial competitiveness."

This work was supported by the Ministry of Science and ICT (MSIT) under the national R&D program for establishing a top-level measurement system and standard framework for intelligent power grids.

- Using a dynamic diamond anvil cell and the European XFEL, scientists captured water crystallizing at 2 GPa in microseconds, revealing multiple freezing pathways via Ice XXI -

- The discovery opens new frontiers in exploring matter and life under extreme conditions -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has successfully observed, for the first time, the multiple freezing-melting process of water under ultrahigh pressure exceeding 2 gigapascals (2 GPa) at room temperature on a microsecond (μs, one-millionth of a second) timescale.

This breakthrough led to the world’s first discovery of a previously unknown crystallization pathway of water and a new 21st ice phase, named Ice XXI.

While ice generally forms when water cools below 0 °C, it can also form at room temperature or even at elevated temperatures above the boiling point. This is because crystallization—the process in which a liquid transforms into a solid—is influenced not only by temperature but also by pressure. At room temperature, pressurized water exceeding 0.96 GPa undergoes a phase transition into ice crystal, that is, Ice VI.

When water freezes, the hydrogen-bonded network among water molecules becomes intricately distorted and rearranged depending on temperature and pressure, resulting in a variety of ice phases during the crystallization process.

A deeper understanding of these complex phase transitions and structural formation mechanisms between water and ice—and the ability to control them under extreme pressure and temperature conditions—could lead to the creation of new materials never before found on Earth.

▲ KRISS researchers observing the crystallization process of supercompressed water using a dynamic diamond anvil cell (dDAC)

▲ Inside the dynamic diamond anvil cell used by the KRISS research team to generate the supercompressed state (A pair of diamond anvils can be seen)

 Over the past century, researchers around the world have identified 20 distinct crystalline ice phases* by varying temperature and pressure conditions. These phases have been discovered across an extremely wide range—over 2,000 K in temperature and more than 100 GPa in pressure. Among them, the region between ambient pressure (0 GPa) and 2 GPa is particularly important, as it represents the most complex zone of water’s phase transitions, where more than ten ice phases are densely clustered.

* Previously, ice phases from Ice I to Ice XX had been reported. Ice I exists in two structural forms: the hexagonal Ice Ih and the cubic Ice Ic.

The Space Metrology Group at KRISS successfully generated a supercompressed liquid state—where water remains liquid state under high pressure exceeding 2 GPa at room temperature, more than twice the known crystallization pressure—using an in-house developed dynamic diamond anvil cell (dDAC*).

* The dDAC is a high-pressure device that uses a pair of diamonds and piezoelectric actuators to dynamically control and observe pressure changes in a microscopic water sample.

▲ Phase diagram of water and ice showing the newly discovered room-temperature high-pressure phase, Ice XXI (blue region)

▲ Historical timeline of ice phase discoveries from Ice I to Ice XX spanning more than a century

▲ Single-crystal image (left) and diffraction pattern (right) of Ice XXI inside the diamond anvil cell (DAC)

 Unlike conventional diamond anvil cells (DACs), which increase pressure by tightening assembly bolts and often cause easy nucleation due to pressure gradients and mechanical perturbations, the dDAC developed by KRISS minimizes mechanical shock during compression and shortens the compression time from tens of seconds to just 10 milliseconds (ms). This innovation enabled water to be highly compressed into the pressure range of the Ice VI phase.

International collaboration research team led by the KRISS scientists captured the crystallization process of supercompressed water using the combination of dDAC and European XFEL (-the world’s largest X-ray free-electron laser facility) with microsecond time resolution. Through these observations, the team discovered very complicated multiple crystallization pathways that had previously been unknown at room temperature, and revealed that these pathways occurred via a new ice phase, named Ice XXI that is 21st crystalline ice phase for the first time in the world.

The KRISS research team identified the detailed structure of ice XXI as well as the multiple crystallization pathways. Surprisingly, the Ice XXI formed at room temperature possesses a remarkably large and complex unit cell—the smallest repeating unit of a crystal lattice—compared to previously known ice phases. Its crystal structure exhibits a flattened rectangular shape, in which the two base edges are equal in length.

▲ KRISS researchers (from left: Dr. Lee Yun-Hee, Dr. Kim Minju, Dr. Lee Geun Woo, and Dr. Kim Jin Kyun) 

with Dr. Cornelius Strohm, beamline operator at the European XFEL, in front of the IC2 high-vacuum X-ray chamber used in the study

▲ High-pressure research team of the KRISS Space Metrology Group

(From left: Dr. Lee Yun-Hee (Principal Research Scientist), Dr. Kim Minju (Postdoctoral Researcher), Dr. Kim Jin Kyun (Postdoctoral Researcher), and Dr. Lee Geun Woo (Principal Research Scientist))

▲ Unit cell structure of ice XXI

This breakthrough was achieved through a large-scale international collaboration involving 33 scientists from South Korea, Germany, Japan, USA, England, together with researchers at the European XFEL and DESY. The project was conceptualized and led by KRISS under the direction of Dr. Lee Geun Woo who served as a principal investigator (PI).

The KRISS research team—including Dr. Kim Jin Kyun (co-first author, postdoctoral researcher at KRISS), Dr. Kim Yong-Jae (co-first author, formerly postdoctoral researcher at KRISS and now at Lawrence Livermore National Laboratory), Dr. Lee Yun-Hee (co-first author, Principal Research Scientist), Dr. Kim Minju (co-author, Postdoctoral Researcher), Dr. Cho Yong Chan (co-author, Principal Research Scientist), and Dr. Lee Geun Woo (corresponding author, Principal Research Scientist)—played a leading role in the experimental design, data acquisition, and structural analysis. Their leadership and sustained efforts were pivotal to the world’s first discovery of Ice XXI, marking a major step forward in high pressure and planetary science.

Dr. Lee Yun-Hee stated, “The density of Ice XXI is comparable to the high-pressure ice layers inside the icy moons of Jupiter and Saturn. This discovery may provide new clues for exploring the origins of life under extreme conditions in space.”

Dr. Lee Geun Woo stated, “By combining our in-house developed dDAC technology with the XFEL, we were able to capture fleeting moments that had been inaccessible with conventional instruments. Continued research into ultrahigh-pressure and other extreme environments will open new frontiers in science.”

This research was supported by the 4000 K-class Rocket Engine Ultra-High Temperature Materials and Measurement Technologies Development Project of the National Research Council of Science & Technology (NST). The results were published in Nature Materials (Impact Factor: 38.5) in October.

KRISS Creates a New Standard for Ophtalmic Imaging

- KRISS’s retina-mimicking eye phantom replicates human retinal structures and microvessels, 

setting a new benchmark for imaging precision and reliability in ophthalmology -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a retina-mimicking eye phantom* that faithfully replicates the structural layers and microvascular network of the human retina.

This innovation provides a new reference for objectively evaluating and calibrating ophthalmic imaging devices, paving the way for more accurate and reliable diagnosis of retinal diseases.

* Phantom: A phantom refers to a tool used to evaluate, analyze, and calibrate the performance of medical imaging devices. It serves as a measurement standard, similar in concept to a crash-test dummy in automotive testing.

▲ (Pic 1) KRISS researchers examining the structure of the retina-mimicking eye phantom

The retina functions much like a camera film, detecting light and transmitting visual information to the brain. In recent years, the prevalence of retinal diseases has been increasing due to factors such as aging, extensive use of electronic devices, and genetic predisposition. Because retinal tissue is difficult to restore once damaged, early diagnosis and continuous monitoring are essential for preventing vision loss.

Currently, ophthalmology clinics use various imaging techniques—such as optical coherence tomography (OCT*) and fluorescein angiography (FA**)—to diagnose different retinal diseases. However, the measurement results often vary across hospitals and device manufacturers, and there is no standardized reference available to evaluate or calibrate these instruments. As a result, the consistency and reliability of diagnostic outcomes have been difficult to ensure.

* OCT: A non-invasive imaging technique that uses light waves to create high-resolution, cross-sectional images of biological tissues.

** FA: An eye test that uses a fluorescent dye and a specialized camera to visualize blood flow in the retina and choroid.

To address this issue, the Nanobio Measurement Group and the Medical Metrology Group at KRISS developed an artificial eye, the retina-mimicking eye phantom, which precisely reproduces the structure and function of the human retina. The phantom was designed like a ruler with marked scales, enabling accurate assessment of diagnostic device performance. When inserted into ophthalmic imaging systems, it allows objective verification and calibration of key aspects including image resolution and field of view.

 ▲ (Pic 2-1) Structure of the retina-mimicking eye phantom developed by KRISS

▲ (Pic 2-2) Application example of the retina-mimicking eye phantom developed by KRISS

▲ (Pic 2-3) Performance evaluation results of ophthalmic imaging devices using the retina-mimicking eye phantom

Conventional retinal phantoms have only replicated a few parts of the retinal vasculature in a simplified manner. In contrast, the phantom developed by the KRISS research team precisely reproduces all 13 structural layers of the retina, along with its curvature, microvascular networks with fluidic flow, and retinal autofluorescence. The phantom matches more than 90% of those of a real human retina, and its multifunctional design allows it to be applied across a wide range of diagnostic platforms, from tomographic imaging systems to angiography devices.

* Autofluorescence : The natural emission of light from biological structures such as mitochondria or lysosomes when they absorb light

This achievement is expected to set a new benchmark for the standardization of medical imaging devices, enhancing the accuracy of retinal disease diagnosis and treatment monitoring. By providing a clear reference for evaluating and calibrating diagnostic instruments, medical institutions can ensure consistent and reliable test results for patients regardless of where their retinal examinations

The newly developed phantom is also expected to be widely utilized in both industry and education. Manufacturers of retinal imaging devices can use the phantom to evaluate and refine prototype performance, as well as to maintain consistent product quality during production. In addition, by using the phantom, which closely mimics the human retina, for clinical training and diagnostic education, medical professionals can further strengthen their expertise.

▲ (Pic 3) Research team the development of the retina-mimicking eye phantom

(From the front row, clockwise: Dr. Lee Sang Won, Head of the Nanobio Measurement Group; Dr. Lee Tae Geol, Principal Research Scientist; 

Dr. Doh Il, Head of the Medical Metrology Group; and Dr. Lee Hyunji, Postdoctoral Researcher at KRISS) 

Lee Sang Won, Head of the Nanobio Measurement Group at KRISS, stated,

“As the demand for retinal disease diagnosis continues to grow, the use of AI-assisted diagnostic methods is increasing. By calibrating ophthalmic imaging systems using this phantom, we can obtain high-quality training data, which will help improve the performance of AI-based diagnostic devices.”

This research was supported by the Global TOP Strategic Research Program of the Ministry of Science and ICT (MSIT) and the Korea Medical Device Development Fund (KMDF). The results were published in Communications Engineering in July 2025.

: AI Reconstructs Microscopic 3D Worlds from Electron Microscopy

- The breakthrough AI algorithm developed by KRISS rapidly turns cross-sectional microscope images into 3D structures 

— reducing analysis time and cost to one-eighth while maintaining high accuracy. -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed an artificial intelligence (AI)-based image segmentation algorithm that can rapidly reconstruct three-dimensional (3D) structures from two-dimensional (2D) cross-sectional images of biological samples captured using a scanning electron microscope (SEM).

The newly developed algorithm requires manual analysis of only about 10% of the total image data, after which it automatically labels the remaining data to train the AI. The trained AI automatically performs segmentation, and the results are reconstructed in 3D. Compared with conventional methods—where researchers had to manually analyze every cross-sectional image—the new approach reduces the time and cost required for 3D visualization by more than half, significantly improving research efficiency.

A SEM captures a series of cross-sectional images of a specimen at intervals of several tens of nanometers and reconstructs them into a 3D structure. Because it enables high-resolution observation of fine internal cellular structures, the SEM is widely used in life science research and medical diagnostics.

▲ KRISS researchers reviewing the results of the AI-based image segmentation algorithm

 Image segmentation is a preprocessing step required for reconstructing 3D structures from SEM images. It involves determining the precise position and shape of specific structures—such as cell nuclei and mitochondria—in each cross-sectional image. By filtering out unnecessary information and clearly highlighting only the target structures, image segmentation enables accurate 3D reconstruction.

Traditionally, image segmentation relied on a supervised learning approach, in which experts manually examined hundreds or even thousands of cross-sectional images and annotated the target structures by hand.
However, this process required significant time and manpower, and the results were often affected by subjective judgment and human error, making it difficult to ensure consistency and reliability in the final 3D reconstructions.

▲ Schematic illustration of the AI-based image segmentation algorithm developed by KRISS

▲ Performance evaluation results of the AI-based image segmentation algorithm developed by KRISS

To address this challenge, the Emerging Research Instruments Group at KRISS developed a semi-supervised learning–based algorithm that uses periodically labeled images as reference points to automatically annotate the adjacent cross sections. For example, if there are 100 cross-sectional SEM images, researchers manually label every tenth image, and the algorithm automatically performs labeling* for the remaining 90 images, completing the full dataset analysis.
This approach dramatically reduces the time and cost required to prepare datasets for AI-based 3D structure reconstruction.

* Labeling: The process of assigning correct class information to data—for instance, marking a region in a cross-sectional image as a ‘cell nucleus‘ or ’mitochondrion.‘

In performance tests using mouse brain cell data, the algorithm developed by the KRISS research team demonstrated accuracy levels within 3% of those achieved by conventional methods, while reducing the required analysis time and cost to approximately one-eighth.
Even when applied to large-scale data with a resolution of 4096 × 6144 pixels, the algorithm maintained both high accuracy and processing speed, showing stable performance throughout.

▲ Emerging Research Instruments Group at KRISS
(From top left, clockwise: Research Student Haam Youngkwon; Senior Research Scientist Park Junhyeong; Principal Research Scientist Jung Haewon; 

Senior Research Scientist Yun Dal Jae; and Head of the Emerging Research Instruments Group Park In Yong)

Senior Researcher Yun Dal Jae of the Emerging Research Instruments Group at KRISS stated, “The technology we developed can be applied not only in the biological sciences but also in a wide range of fields that require automated image analysis, such as semiconductor defect inspection and new materials development. In particular, it can be highly useful in areas where it is difficult to obtain AI training data due to privacy concerns or budget constraints.”

This research, supported by the KRISS Basic Program, was published in Microscopy and Microanalysis (Impact Factor: 3.0) in June, and was selected as a Highlight Paper in that issue.

- KRISS Pioneers Domestic Innovation, Achieving Self-Reliant Technology Transfer to Defense Sector -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has successfully localized core Radar Stealth technologies through indigenous development, without reliance on foreign technologies. This achievement is a significant milestone, laying the foundation for the establishment of stealth weapon systems in Korea, which have long been difficult to import due to their classification as national strategic military assets.

As global military tensions rise and competition in advanced weapon development intensifies, the importance of developing stealth weapon systems has increased significantly. Radar stealth technology, which absorbs or scatters electromagnetic waves to avoid detection by enemy radar, is a key element for ensuring both autonomy and concealment in weapon systems. As this technology is classified as a strategic military asset in leading countries, its import, particularly software and testing equipment, is strictly restricted, highlighting the continuous need for domestic development.

KRISS has successfully developed both a Frequency Selective Surface (FSS) design software and an electromagnetic wave evaluation system for radomes*—a vital component in radar stealth systems. This is the first case in which every stage of the process, from design, prototype fabrication, to performance testing, has been accomplished entirely using domestic technology, without reliance on foreign systems.

 * Radome: A radome is a structural enclosure designed to protect radar or other antenna systems from external environmental factors. Typically constructed from materials that allow designated electromagnetic waves to pass through with minimal interference, a radome shields the antenna from weather conditions (such as rain, snow, and wind) and physical impacts, while also preventing accidents involving rotating antennas.

 ▲ Schematic of FSS Degisn Software Developed by KRISS

▲ Schematic of High-Speed Radome Evaluation Technology Developed by KRISS

Radomes are hemispherical structures that enclose radar and communication antennas on aircraft, missiles, or other vehicles. They must be precisely designed to protect the internal systems from external environmental conditions while allowing electromagnetic signals to pass through with minimal distortion. In defense applications, radomes are subjected to extreme conditions such as high thermal loads and intense shock during high-speed flight. As such, they must simultaneously meet multiple performance requirements, including high electromagnetic transmittance and phase stability.

The FSS in a radome functions as a type of frequency filter, designed to selectively transmit or reflect electromagnetic waves at specific frequencies. To enhance the performance of the FSS, high-performance electromagnetic simulation software is essential for accurately modeling wave transmission characteristics. However, widely used commercial software packages are associated with significant cost barriers, with licenses for individual users exceeding KRW 100 million (approx. USD 75,000) and annual maintenance fees surpassing KRW 20 million (approx. USD 15,000).

▲ Dr. KIM Jin-Hyeok(left) and Dr. YUN Dal-Jae (right), senior researchers at KRISS, are measuring a radome using an AI-powered antenna measurement equipment.

 ▲  Dr. HWANG In-June (left) and Dr. JUNG Haewon (right) of KRISS are aligning the distance and position of an antenna for FSS measurement.

KRISS has developed new FSS design software incorporating artificial intelligence (AI) and parallel computation techniques. Optimized for analyzing radome structures composed of multilayer composite materials, the software delivers over a 50-fold increase in design speed compared to conventional tools.

Furthermore, KRISS has also developed an electromagnetic wave evaluation system that enables in-house performance testing and optimization of radomes. Traditionally, the process used to take over a month to complete electromagnetic tests required to meet the stringent performance standards of defense-grade radomes. By applying artificial intelligence (AI) technology, the newly developed system enables performance measurements more than five times faster than traditional testing methods. This advancement is expected to significantly reduce both the time and cost needed to deploy radomes in operational settings.

▲ Research Team for Indigenous Development of Core Radar Stealth Design and Evaluation Technologies

(From left: Dr. JUNG Haewon, Principal Researcher; Dr. YUN Dal-Jae, Senior Researcher; Dr. HWANG In-June, Senior Researcher; Dr. LEE In-Ho, Principal Researcher

; Dr. HONG Young-Pyo, Head of the Electromagnetic Wave Metrology Group; Dr. KIM Jin-Hyeok, Senior Researcher)

The technology, developed through collaborative research across four KRISS research groups*, has been transferred to Korea Electrotechnology Research (KER), a company specializing in advanced defense weapon systems and precision electromagnetic measurement equipment. The technology transfer, valued at 500 million KRW, was formalized through an agreement signing ceremony held at KRISS on Tuesday, August 5.

  * Electromagnetic Wave Metrology Group, Emerging Research Instruments Group, Quantum Electricity and Magnetism Metrology Group, and Material Property Metrology Group.

Dr. HONG Young-Pyo, Head of the Electromagnetic Wave Metrology Group at KRISS, stated, "The technologies we have developed are not only applicable to the defense sector but also hold great potential for various radar-related industries, including mobility, maritime, and aerospace applications."

These research results were published in July in IEEE Transactions on Microwave Theory and Techniques, the world’s leading journal in the field of electromagnetics. Additionally, the design software and measurement equipment technologies have been separately filed for patent protection.

Cost-effective, highly sensitive technology adaptable to cancer, brain disorders, and infectious diseases beyond Alzheimer’s. -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a diagnostic platform that amplifies the unique optical signals of molecules by more than a hundred million times, enabling the precise detection and quantification of trace amounts of Alzheimer’s disease biomarkers in body fluids. With a simple body fluid test, the platform can quantify multiple biomarkers with ultrasensitivity and high reliability, complementing conventional imaging-based diagnostics and enabling early diagnosis and monitoring of disease progression.

Alzheimer’s disease is a leading degenerative brain disorder in which neurons in the brain gradually deteriorate, causing progressive decline in cognitive functions such as memory and reasoning. It accounts for roughly 60–70% of dementia cases worldwide, and with no fundamental cure currently available, early diagnosis and continuous management are essential.

▲ Dr. You Eun-Ah (left), Principal Research Scientist, and Dr. Kim Ryeong Myeong (right), Senior Research Scientist at KRISS, 

analyzing biomarker detection results using SERS nanoparticle technologymultiplexed SERS sensing platform.

At present, Alzheimer’s disease is primarily diagnosed using imaging modalities such as PET* and MRI**. However, each examination can cost over 1 million KRW (approximately USD 750) and requires specialized facilities. Moreover, these imaging techniques can only detect the disease once it has progressed beyond a certain stage, making early detection difficult.

* PET (Positron Emission Tomography): A nuclear medicine imaging technique that visualizes functional and biochemical changes inside the body by injecting a radiopharmaceutical and detecting its distribution.

** MRI (Magnetic Resonance Imaging): A non-invasive imaging method that uses strong magnetic fields and radio frequency pulses to generate high-resolution images of soft tissues and blood vessels without the need for contrast agents.

Simpler body fluid tests have so far lacked sufficient accuracy, preventing them from being used as reliable diagnostic tools.

Two peptides found in the brain—amyloid beta (Aβ) 42 and Aβ 40—are closely associated with Alzheimer’s disease. Measuring their concentrations in body fluids and calculating the Aβ42/Aβ40 ratio enables early assessment of disease progression.

However, with the detection performance of conventional enzyme-linked immunosorbent assay (ELISA) methods, it has been difficult to simultaneously and accurately detect these two peptides in ultra-low concentrations present in blood, cerebrospinal fluid, and other body fluids.

* Peptide: A short chain of amino acids linked by peptide bonds, representing an intermediate between amino acids and proteins, and playing key roles in regulating various biological functions.

** Amyloid beta (Aβ): The main component of amyloid plaques found in the brains of Alzheimer’s patients. Composed of 36–43 amino acids, Aβ is derived from amyloid precursor protein (APP) through cleavage by β-secretase and γ-secretase, and is known to cause neurotoxicity that contributes to disease onset.

*** ELISA (Enzyme-Linked Immunosorbent Assay): A biochemical method widely used in laboratories to detect and quantify specific substances based on antigen–antibody interactions and enzyme-mediated signal generation.

The Medical Metrology Group at KRISS has developed an ultrasensitive multiplexed quantitative sensing platform based on Surface-Enhanced Raman Spectroscopy (SERS), which is over 100,000 times more sensitive than conventional ELISA methods and capable of accurately distinguishing and quantifying multiple biomarkers.

SERS is an analytical technique that greatly amplifies the unique optical signals generated when light interacts with molecules by using metallic nanostructures, enabling the precise detection of even trace amounts of molecules.

The research team developed distinct, multi-type gold nanoparticles with a sunflower-shaped cross-section, capable of producing strong and uniform SERS signals from individual particles. This design overcomes the issue of signal non-uniformity caused by variations in interparticle spacing in conventional spherical gold nanoparticles.

By creating a high-density, uniform distribution of signal enhancement sites both inside and on the surface of each particle, the nanoparticles generate strong and highly reproducible signals even at the single-particle level. As a result, the platform achieves excellent quantitative performance proportional to the concentration of target molecules, while enabling the simultaneous detection of multiple distinct targets.

Using the multiplex SERS nanoparticles, each assigned a unique optical ID, the researchers successfully quantified ultra-trace levels of Aβ42 and Aβ40 at concentrations as low as 8.7 × 10?17 g/mL and 1.0 × 10?15 g/mL, respectively. This represents world-leading performance in terms of both sensitivity and dynamic detection range for multiplex quantitative analysis.

▲ (Pic 3) Research team behind the development of the SERS-based ultrasensitive multiplexed quantitative sensing platform.

(Back row, from left, clockwise: Dr. Baek Ahruem, Senior Research Scientist; Dr. Kim Ryeong Myeong, Senior Research Scientist; Dr. You Eun-Ah, Principal Research Scientist)

Dr. You Eun-Ah, Principal Research Scientist at the KRISS Medical Metrology Group, stated,

“The sensing platform we have developed can be mass-produced at low cost and flexibly adapted to a wide range of biomarkers.

Beyond Alzheimer’s disease, it holds high versatility and strong commercialization potential for the early and rapid in vitro diagnosis and monitoring of various diseases, including cancers, neurological disorders, and infectious diseases.”

This research was supported by the National Research Council of Science & Technology (NST) Research Initiative Program and the Basic Research Program of KRISS. The results were published in April in Biosensors & Bioelectronics (Impact Factor: 10.5), a leading international journal in the field of analytical chemistry.

“Absolute Distance Measurement System”

Nearing the Quantum Limit

- Fast, precise, and field-deployable: A quantum-level optical frequency comb system 

that measures 0.34 nanometers in just 25 microseconds -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has successfully developed a length measurement system that achieves a level of precision approaching the theoretical limit allowed by quantum physics.

The system boasts world-leading measurement accuracy while maintaining a compact and robust design suitable for field deployment, making it a strong candidate to serve as the new benchmark for next-generation length metrology.

▲ Schematic of the absolute distance measurement system based on the optical frequency comb interferometry developed by KRISS

Currently, the most precise instruments for measuring length are national length measurement standards, which define the unit of one meter. These instruments, operated by leading national metrology institutes including KRISS, utilize interferometers based on single-wavelength lasers to perform ultra-precise length measurements.

Single-wavelength lasers are characterized by extremely uniform wave distributions—like the evenly spaced markings on a ruler—allowing for measurement precision at the nanometer scale (1–10 nm, or one-billionth of a meter).

* Interferometer: A device that measures distance or displacement with high precision by analyzing interference patterns created when two beams of light meet.

However, the length measurement standards are limited in the range of distances they can measure at once, because single-wavelength lasers have a very narrow spectral bandwidth. In other words, while their ruler markings are very fine, the ruler itself is short.

To measure distances beyond the laser’s wavelength range, multiple repeated measurements must be stitched together, significantly increasing the total measurement time. This process also requires precise mechanical systems to move the interferometer stably, resulting in considerable time and spatial constraints.

In contrast, absolute distance measurement systems are designed to measure long distances in a single operation, though with lower precision. These systems typically calculate the distance by emitting a light pulse from a reference point to a target and measuring the time it takes to return. Thanks to this relatively simple method, the systems can be miniaturized and are capable of fast, long-range measurements, making them widely used in industrial settings. However, conventional absolute distance measurement systems are limited to a precision of only a few micrometers (µm), since measuring the time of flight (ToF) of light with ultra-fine resolution remains extremely challenging using current technologies.

The Length and Dimensional Metrology Group at KRISS has successfully enhanced the precision of absolute distance measurement systems to the level of national length standards by employing an interferometer based on an optical frequency comb (OFC). The research team devised a method to integrate an OFC into an spectlra interferometry based absolute distance measurement setup. An optical frequency comb is a spectrum composed of thousands of discrete, evenly spaced frequency lines—similar to the keys of a piano. Unlike conventional interferometric light sources, optical frequency combs feature both a broad spectral bandwidth and precisely spaced wavelengths, enabling simultaneous high-precision measurement over long distances.

▲ Measurement principle of the optical frequency comb-based absolute distance measurement system developed by KRISS

▲ Measurement results from the optical frequency comb-based absolute distance measurement system developed by KRISS

▲ Comparison of measurement results with other national absolute distance measurement systems

The absolute distance measurement system based on optical frequency comb spectral interferometry, developed by the KRISS research team, combines the precision of national length standards with the convenience of absolute measurement systems. The system achieves a precision of 0.34 nanometers, representing one of the highest levels of accuracy among existing technologies, and approaching the quantum-limited precision defined by the laws of quantum physics. With a measurement speed of 25 microseconds (μs), it operates rapidly and reliably enough for field deployment, offering significant potential to enhance precision metrology in high-tech industries.

▲ KRISS researchers inspecting the electro-optic modulated optical frequency comb laser

(Left: Dr. Jang Yoon-Soo / Right: Dr. Kim Dae Hee)

▲ KRISS Length and Dimensional Metrology Group

(From left: ON yoonkwon, Student Researcher; Dr. Kim Dae Hee; Dr. Jang Yoon-Soo; Eom Sunghoon, Senior Engineer)

The research team plans to continue developing the system by evaluating its measurement uncertainty and refining its performance, with the goal of establishing it as a next-generation national length standard.

Dr. Jang Yoon-Soo, senior researcher at the Length and Dimensional Metrology Group at KRISS, emphasized,

“The competitiveness of future industries such as AI semiconductors and quantum technologies hinges on the ability to accurately measure and control distances at the nanometer scale. This achievement marks a significant step for Korea toward becoming a leading country in establishing next-generation length standards.”

This research was supported by KRISS's Basic Research Program and was published in June in Laser & Photonics Reviews (Impact Factor: 10.0), a prestigious journal in the field of optics.

and Immune Response Induction"

- KRISS Develops Multifunctional Nanomaterial Surpassing Traditional Single-Function Limits -

- Expected to Be a Next-Generation Treatment Platform -

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has successfully developed a nanomaterial* capable of simultaneously performing cancer diagnosis, treatment, and immune response induction. Compared to conventional nanomaterials that only perform one function, this new material significantly enhances treatment efficiency and is expected to serve as a next-generation cancer therapy platform utilizing nanotechnology.

* Nanomaterial: Particles with a diameter between 1 and 100 nanometers (nm, 1 nm = one-billionth of a meter)

▲ KRISS researchers observing the imprinting equipment for nanodisk synthesis

(Dr. Lee Eun Sook, left; Dr. Lee Jinhyung, right)

Currently, cancer treatments primarily include surgery, radiation therapy, and chemotherapy. However, these treatments have significant limitations, as they not only affect cancerous areas but also cause damage to healthy tissues, leading to considerable side effects.

Cancer treatment using nanomaterials has emerged as a next-generation technology that aims to overcome the limitations of conventional treatments. By utilizing the physical and chemical properties of nanomaterials, it is possible to precisely target and deliver drugs to cancer cells and affected areas. Additionally, personalized treatments based on individual genetic profiles are now possible, offering a therapy that significantly reduces side effects while improving effectiveness compared to traditional methods.

The KRISS Nanobio Measurement Group has developed a new nanomaterial that not only allows real-time monitoring and treatment of cancerous areas but also activates the immune response system. The nanomaterial developed by the research team is a triple-layer nanodisk (AuFeAuNDs), with iron (Fe) inserted between gold (Au). The design of the nanomaterial, which features iron at the center of a disc-shaped structure, provides superior structural stability compared to traditional spherical materials. Additionally, by applying a magnet near the tumor site, the magnetic properties of the iron allow the nanomaterial to be easily attracted, further enhancing treatment efficiency.

▲ Schematic diagram of the multifunctional nanomaterial treatment platform developed by KRISS

▲ Cancer treatment experimental data of the multifunctional nanomaterial developed by KRISS

The nanodisk developed by the research team is equipped with photoacoustic (PA) imaging capabilities, allowing for real-time observation of both the tumor's location and the drug delivery process. PA is a technique that visualizes the vibrations (ultrasound) generated by heat when light (laser) is directed at the nanodisk. By using this feature, treatment can be performed at the optimal time when the nanomaterial reaches the tumor site, maximizing its effectiveness. In fact, in animal experiments, the research team successfully tracked the accumulation of nanoparticles at the tumor site over time using PA imaging, identifying that the most effective time for treatment is 6 hours after the material is administered.

Furthermore, this nanodisk can perform three different therapeutic mechanisms in an integrated manner, which is expected to treat various types of cancer cells, unlike materials that are limited to single therapies. While conventional nanomaterials used only photothermal therapy (PTT), which involves heating gold particles to eliminate cancer cells, the nanodisk developed by the research team can also perform chemical dynamic therapy (CDT) by utilizing the properties of iron to induce oxidation within the tumor, as well as ferroptosis therapy.

After treatment, the nanodisk also induces immune response substances. The developed nanodisk prompts cancer cells to release danger-associated molecular patterns (DAMPs) when they die, which helps the body recognize the same cancer cells and attack them if they recur. In animal experiments, the research team confirmed that the generation of warning signals through the nanodisk led to an increase in immune cell count by up to three times.

▲ KRISS Nanobio Measurement Group

(From the front left, clockwise: Dr. Na Hee-Kyung, Dr. Lee Jinhyung, Dr. Lee Eun Sook)

Dr. Lee Eun Sook stated, "Unlike conventional nanomaterials, which are composed of a single element and perform only one function, the material developed in this study utilizes the combined properties of gold and iron to perform multiple functions."

This research was supported by the Ministry of Science and ICT’s ‘Next-Generation Advanced Nanomaterials Measurement Standard System Establishment Research Project’ and was published in February in Chemical Engineering Journal (Impact Factor: 13.4).

- KRISS unveils a detachable acoustic lens that allows easy focus adjustment in ultrasound devices -

- Enabling high-quality resolution tailored to specific inspection needs, 

improving accuracy in medical diagnostics and industrial safety inspections -

▲ Researchers Who Developed the Detachable Aspheric Acoustic Lens

(Back row, from left clockwise: Dr. Doh Il, Head of the Medical Metrology Group; Dr. Baik Kyung Min; Dr. Kim Yong Tae)

The Korea Research Institute of Standards and Science (KRISS, President Lee Ho Seong) has developed a detachable acoustic lens that allows for easy adjustment of the focal length in ultrasonic inspection equipment. Much like swapping lenses on a DSLR camera to improve image quality, this technology enables users to optimize the resolution of ultrasonic imaging systems for specific inspection tasks. The innovation is expected to significantly enhance accuracy in both medical diagnostics and industrial safety inspections.

Ultrasonic imaging technology works by transmitting sound waves into an object or the human body and capturing the reflected signals to visualize internal structures. Among these technologies, the C-scan method is known for its ability to generate high-resolution images. It is widely used in diagnostic medical equipment for tasks such as cancer detection, as well as in nondestructive testing (NDT) systems to assess defects in aircraft components and industrial pipelines.

To produce high-resolution ultrasound images, it is essential to increase the intensity of the transmitted and reflected ultrasound waves and precisely control the focal length. For this purpose, focused ultrasound transducers are commonly used in C-scan ultrasound inspection systems. These devices concentrate the broadly dispersed ultrasound energy directly onto the target area, thereby enhancing image quality.

However, a major limitation is that each focused ultrasound transducer has a fixed focal length. This means that multiple transducers with different focal lengths must be purchased, leading to high costs. Moreover, it is difficult to fine-tune the focus to match the position, size, or shape of the object being examined, making it challenging to achieve optimal resolution in ultrasound imaging.

To overcome this limitation, the Acoustics, Ultrasound and Vibration Metrology Group at KRISS has developed ‘a detachable acoustic lens design technology’. By attaching the newly developed lens to a focused ultrasound transducer with a fixed focal length, users can adjust the focal distance to suit the inspection target—without needing to replace the equipment. This enables optimized image resolution tailored to the specific object being examined.

▲ Detachable Aspheric Acoustic Lens Developed by KRISS

Notably, the acoustic lens developed by the KRISS research team is designed with an aspheric shape, offering clearer focus and higher resolution compared to conventional spherical lenses. Traditional acoustic lenses are typically spherical, which leads to spherical aberration—blurring at the edges of the image due to the lens shape. To address this, the team also devised a foldable design that allows the lens size to be flexibly adjusted to match the attachment area.

When the KRISS-designed acoustic lens is attached to a flat ultrasound transducer with low resolution, it can deliver performance comparable to that of a focused ultrasound transducer. The team developed both convex acoustic lenses for focused transducers and flat-form acoustic lens designs.

▲ Acoustic Ray Tracing Diagram of the Detachable Aspheric Lens Developed by KRISS

▲ Analysis of Phantom Model Simulating the Human Body Using C-Scan Ultrasound Equipment with the Detachable Aspheric Acoustic Lens

When the newly developed acoustic lens was attached to a C-scan ultrasound imaging device and used to analyze a phantom model simulating the human body, the system successfully visualized fine structures as small as 25 micrometers (μm, one millionth of a meter). This represents a resolution approximately 1.5 times higher than that of a device without the lens at the same focal distance.

Dr. Kim Yong Tae, Principal Research Scientist of the Acoustics, Ultrasound and Vibration Metrology Group at KRISS, stated, “We plan to expand the application of this lens design technology beyond C-scan systems to various types of ultrasound imaging.”

This research was supported by the Korea Medical Device Development Fund, funded by the Korean government (the Ministry of Science and ICT, the Ministry of Trade, Industry and Energy, the Ministry of Health & Welfare, and the Ministry of Food and Drug Safety). It was published in January in Measurement Science and Technology (Impact Factor: 2.4).

 * Note: This research was supported by the Korea Medical Device Development Fund (NTIS Project Number: 9991007024, KMDF Project Number: KMDF_PR_202011B03-04).

- KRISS Develops Impedance Measurement Standards for 6G Low Earth Orbit Satellite Communication -

▲ KRISS Electromagnetic Wave Metrology Group

(Clockwise from the left: Dr. Cho Chi Hyun, Principal Research Scientist; Lee Sangsu, Senior Engineer; Dr. Kang Tae Weon, Principal Research Scientist)

The Korea Research Institute of Standards and Science (KRISS, President: Lee Ho Seong) has established standards that can reliably verify the performance of Korea's developing 6G low Earth orbit satellite communication system.

Recently, the communication paradigm is shifting to three-dimensional communication utilizing both air and space. While two-dimensional communication faces limitations in areas such as mountainous regions and oceans where base stations are difficult to build, three-dimensional communication can provide fast services anytime and anywhere without blind spots. Even in the event of war or disasters that disrupt ground-based networks, communication can be maintained stably.

6G low Earth orbit satellites, which relay data at altitudes close to the Earth's surface (between 200 km and 2,000 km), are a core infrastructure for three-dimensional communication. A representative commercial example is the "Starlink" system, which is being built by SpaceX in the United States. Korea also launched its first domestically developed small low Earth orbit satellite, "NEONSAT 1," in April last year as part of the effort to build a "Korean-style Starlink."

For the successful commercialization of 6G low Earth orbit satellite communication, standards that can accurately measure and evaluate communication quality are essential. However, until now, there has been no established measurement standard for our 6G low Earth orbit satellite communication system, making it difficult to reliably verify the technology of domestically developed satellites.

The KRISS Electromagnetic Wave Metrology Group has developed an electromagnetic wave impedance measurement standard for waveguides, which are key components of 6G low Earth orbit satellite communication systems. A waveguide is a structure that transmits electromagnetic waves along a specific path, capable of delivering high-frequency signals with minimal loss and excellent durability. It is used as the signal transmission channel in satellite communication systems. The research team prioritized establishing an impedance measurement standard for the X-band (8-12 GHz) frequency range, which is used in domestically developed small low Earth orbit satellites.

▲ From left to right: ① Standard shape measurement ② Impedance measurement of the standard ③ Network analyzer calibration and uncertainty calculation

This development of the measurement standard will significantly enhance the technological reliability of components used in domestically developed low Earth orbit satellites. With precise measurement standards, various performance indicators—such as signal strength, latency, and propagation loss—can be quantitatively assessed during the satellite’s prototype phase, leading to improvements that enhance quality.

In addition, by accurately predicting the required communication output for satellite components, custom designs can be made, which will help reduce unnecessary costs and shorten the development timeline.

KRISS has also developed waveguide impedance calibration technology to distribute the newly established measurement standards to the industrial sector. In the past, calibrating network analyzers used for impedance measurement required sending equipment overseas, which was time-consuming and costly. However, with the new domestic technology, accurate calibration can now be performed at a lower cost.

▲ Graph comparing the uncertainty of KRISS-developed calibration technology((a)~(c)) and existing calibration method((d)~(f))

Dr. Cho Chi Hyun, Principal Research Scientist of the KRISS Electromagnetic Wave Metrology Group, stated, "The standard developed this time can be applied not only to satellite communication, but also to all fields where waveguides are used, such as radar systems and aircraft." He added, "We will continue to establish electromagnetic wave measurement standards needed by domestic industries and the defense sector, contributing to the enhancement of national industrial competitiveness."

This research was published in February in the international journal of electronics and information communication, IEEE Transactions on Instrumentation and Measurement (Impact Factor: 5.6).

- Precision Control of Single Electron Energy Using a Sieve-Like Filter -

- Enhancing Quantum Stability and Accelerating High-Performance Qubit Development -

The Korea Research Institute of Standards and Science (KRISS, President: Dr. Lee Ho Seong) has developed a technology that controls the energy of single electrons in the desired form. This technology reduces the instability of electrons caused by external environments and enables stable quantum state implementation, making it a foundational technology to enhance the performance of single-electron qubits.

▲ KRISS researchers analyzing the time-energy distribution of single electrons that have passed through an energy filter

Electrons are fundamental particles that make up atoms, and when their paths are divided, they exhibit the quantum superposition phenomenon, passing through both paths (0 and 1) simultaneously. This characteristic can be utilized in information processing to create qubits. Single-electron qubits are highly regarded as a technology for scaling quantum computing due to their excellent integration, with the theoretical potential to implement dozens of qubits in a small area.

However, improving the performance of single-electron qubits has been challenging due to their extreme sensitivity to external environments. The stability and accuracy of a qubit’s quantum state directly determine its performance, yet electrons, being incredibly small and sensitive, make it difficult to achieve a stable quantum state. Additionally, their energy state is highly susceptible to interactions with the surrounding environment and other electrons, often leading to instability and a rapid loss of quantum properties.

▲ (Top) Schematic of the energy filter used by KRISS researchers to control single electrons 

(Bottom) KRISS researchers confirming the energy form of single electrons using Wigner distribution

The Quantum Device Group at KRISS has developed an advanced technology that precisely controls the energy of single electrons and reduces their instability using an energy filter. The newly developed energy filter is strategically placed within a conductive channel and functions similarly to a kitchen sieve. It selectively allows only electrons with energy above a specific threshold to pass through, while reflecting the rest. The researchers created single electrons in a quantum dot, then applied an appropriate voltage to a quantum point contact to form an energy filter. This approach successfully enabled the passage of only high-energy electrons, reducing energy uncertainty by more than half.

This technology is expected to be widely used in the development of single-electron-based quantum information processing technologies, including high-performance qubits. By eliminating unnecessary energy distributions and manipulating electrons within a specific energy range, the quantum phenomena of the electrons can be implemented more stably, while minimizing interactions with external environments and other electrons.

▲ (Top) KRISS researchers cooling the device to ultra-low temperatures using a cryogen-free dilution refrigerator 

(Bottom) KRISS Quantum Device Group

(From left to right: Park Wanki, Postdoctoral Researcher; Bae Myung-Ho, Principal Research Scientist; Kim Minsik, Research Student)

In addition, the research team has developed a technology to visualize the shape of single electrons controlled by the energy filter on a 2D graph. They devised a method to compare the shape of the single electron before and after passing through the energy filter using Wigner distribution*. By intuitively observing the time-energy information of the single electron, which changes depending on the conditions, on a digital 2D graph, the researchers can precisely identify the quantum properties of the single electron that were previously overlooked in earlier experiments.

* Wigner Distribution: A method of visually analyzing the quantum state of an electron by converting it into a distribution function of time (position) and energy (momentum). In this experiment, the research team developed a technique to compare the energy changes of single electrons using Wigner distribution and analyze it in detail by converting it into digital signals.

Dr. Bae Myung-Ho stated, "This achievement will contribute to enhancing the applicability of quantum information technologies based on single electrons."

This research was conducted in collaboration with Jeonbuk National University, Korea Advanced Institute of Science and Technology (KAIST), and Korea Institute of Science and Technology (KIST), and the results were published in Nano Letters (IF: 9.6) in October 2024.

- Installing on Hydrogen refuelling Stations to Monitor Impurities in Hydrogen Fuel Supplied to Vehicles 24/7 -

- Preventing Hydrogen Vehicle Accidents Caused by Impurities in Advance... Expected to Further Improve Production Quality -

The Korea Research Institute of Standards and Science (KRISS, President: Dr. Lee Ho Seong) has developed equipment that monitors the quality of hydrogen fuel supplied to vehicles through hydrogen refuelling stations in real-time. This equipment is expected to prevent hydrogen vehicle accidents caused by impurities in the hydrogen fuel and improve the quality of hydrogen production.

▲ KRISS Semiconductor and Display Metrology Group

(From left to right: Trisna Beni Adi, UST Research Student; Park Miyeon, UST Research Student; Lee Jeongsoon, 

Principal Research Scientist; Kim Dongkyum, Postdoctoral Researcher; Kim Sang Woo, Postdoctoral Researcher)

Hydrogen fuel is more prone to contamination during production, transportation, and storage compared to conventional fuels. This is because hydrogen production is more complex than conventional fuel production, and the high-pressure processes involved in storage, transportation, and usage increase the likelihood of impurities being introduced.

If contaminated hydrogen fuel is injected into a hydrogen vehicle, the risk of explosion and accidents significantly increases. Impurities in the fuel damage the catalyst in the fuel cell, causing overheating and a decline in performance. This can trigger unexpected chemical reactions, raising the risk of hydrogen explosions. Additionally, there is concern about secondary accidents due to a decrease in engine performance.

In Korea, the quality of hydrogen fuel is monitored by inspection agencies that visit fuel production sites quarterly, collect fuel samples, and measure impurities using specialized equipment. However, this process presents significant challenges. Detecting impurities that occur outside the scheduled inspection periods is difficult, and identifying the root cause and nature of the issue proves to be even more complex, making it hard to provide effective, real-time assistance.

Although expensive foreign equipment is used on-site for testing impurities in hydrogen production, these devices can only analyze one or two components at a time. Additionally, the maintenance of such equipment is problematic, complicating the process of conducting thorough and continuous quality inspections.

As hydrogen infrastructure—including refueling stations and production facilities—continues to expand, the demand for hydrogen fuel quality analysis has grown substantially. This surge in demand has highlighted the need for easy-to-use, domestically produced, real-time monitoring equipment that can ensure the quality of hydrogen fuel at all times.

▲ (Top) 'Real-Time Monitoring Equipment for Hydrogen Fuel Quality' Developed by KRISS

(Bottom) Schematic of the 'Real-Time Monitoring Equipment for Hydrogen Fuel Quality' Developed by KRISS

Recently, KRISS's Semiconductor and Display Metrology Group successfully developed equipment that monitors, in real-time, the components and concentrations of impurities in hydrogen fuel supplied to vehicles through refuelling stations.

Dr. Lee Jeongsoon, Principal Research Scientist at KRISS's Semiconductor and Display Metrology Group, who developed the real-time monitoring equipment for hydrogen fuel quality, explained, "The equipment displays both the measurement values and their uncertainty (the degree of doubt in the results). The analysis values and uncertainty, obtained using standard materials, are traceable to standards, ensuring the reliability of the results.”

The equipment developed by the research team is capable of accurately measuring eight of the fourteen impurities that are regulated by ISO. If the concentration of any impurity in the hydrogen fuel exceeds the standard threshold, the management system sends a warning signal, allowing the operator to detect and take action before contaminated fuel is injected into the vehicle.

*The 8 impurities measured: Water vapor (H₂O), Oxygen (O₂), Argon (Ar), Carbon dioxide (CO₂), Methane (CH₄), Carbon monoxide (CO), Nitrogen (N₂), Hydrogen sulfide (H₂S)

▲ KRISS Principal Research Scientist Lee Jeongsoon (left) and Postdoctoral Researcher Kim Sang Woo 

(right) are inspecting the monitoring equipment installed at the hydrogen bus refuelling station in Chungju City.

By applying the newly developed equipment at hydrogen refuelling stations, it will be possible to continuously monitor and maintain the quality of hydrogen fuel, which is expected to enhance the safety of hydrogen vehicles and reduce user concerns. Additionally, at hydrogen production facilities, the equipment will enable easy and accurate inspection of the quality of the hydrogen fuel being produced, which is expected to further improve the quality of domestically produced hydrogen.

Dr. Lee Jeongsoon stated, "We are currently conducting a demonstration of the equipment at the hydrogen bus refuelling station in Chungju City, and after the demonstration is completed, we plan to transfer the technology to domestic companies."

This research achievement was supported by KRISS's basic projects and the Ministry of Trade, Industry and Energy’s (MOTIE) project, "Development of Essential Equipment Localization Technology for Enhancing the Safety of Hydrogen refuelling Stations and Pipeline Networks."

Lifetime of Semiconductor processing equipment parts Can Be Checked in Real Time

- KRISS has developed a measurement system for real-time diagnosis of components of the semiconductor plasma process -

- Contaminant particles caused by corrosion can be preemptively prevented to increase semiconductor yield and save costs -

The Korea Research Institute of Standards and Science (KRISS), led by President Lee Ho Seong has successfully developed a system that diagnoses the lifetime of parts used in the semiconductor plasma processes in real time. It is expected that the new system can help preemptively prevent contaminant particles generated by corrosion of components, thereby upgrading the semiconductor yield as well as the stability and cost efficiency of the process.

▲ KRISS Emerging Material Metrology Group 

(Clockwise from the front left: Principal Researcher Yun, Ju Young; Senior Researcher Maeng, SeonJeong; Student researcher Jeong, In-seok, and Student Researcher So, Jong-ho)

The plasma process involves precisely etching the surface of a semiconductor substrate or depositing a specific material using a gas ionized into a plasma state. The plasma process is considered a key process directly related to semiconductor yield because the circuit pattern on a semiconductor device must be precisely and uniformly implemented in the plasma process to achieve the performance targeted at the design stage.

Fine contaminant particles generated in the plasma processes have a fatal impact on the process quality. Most contaminant particles are generated when the internal coating parts of process equipment (chambers) are exposed to the plasma environment and corrode. The particles fall on the wafers being processed, generating defective products, and are deposited on the inside the chamber of th equipment , lowering the process performance.

Therefore, it is necessary to diagnose the size and number of particles and predict the lifetime of parts used in the plasma process ; however, there was no real-time measurement technology. In most cases, the remaining lifetime of components was indirectly estimated by analyzing the surface of the wafers completely manufactured after the process; however, yield reduction and cost loss occurred due to process defects.

▲ The real-time system for measuring the lifetime of plasma process components developed by KRISS

▲ Real-time contaminant particle measurement data obtained by the measurement system developed by KRISS

The Emerging Material Metrology Group of KRISS has developed a measurement system that can be attached to plasma process equipment to monitor the status of parts inside the chamber in real time. The system consists of a test sample holder, a capture device, and an analysis sensor. After attaching a test sample inside the equipment, the film of the component peeled off due to plasma exposure is captured and analyzed by the sensor. The system is capable of analyzing thousands of fine particles of a few micrometers (μm) or less generated during the process, enabling real-time diagnosis of the status and remaining lifespan of the components.

When the newly developed system is applied to manufacturing sites, parts can be replaced in a timely manner before contaminant particles are generated. It is expected that the process stability and productivity can be increased and costs due to unnecessary component replacement can be reduced.

In particular, while it previously took about several days to stop the process, disassemble the equipment, and analyze the components to check their lifespan, the new system allows managers to immediately check it based on the objective data whenever they want, which can also reduce sales losses caused by process discontinuation.

Furthermore, the newly developed system serves as a test bed for semiconductor equipment and component manufacturers in Korea to test the performance of prototypes and obtain official test results.

Principal Researcher Yun, Ju Young of the Emerging Material Metrology Group of KRISS said, “Through the operation of a demonstration test bed, we will increase the reliability and competitiveness of the equipment and components manufactured in Korea and contribute to the localization of semiconductor production processes that are highly dependent on imported equipment.”

This technology is ready for immediate commercialization, and has already been transferred to a semiconductor equipment company and is being used in actual semiconductor production sites. The results of this study were accepted for publication in September 2024 in the Journal of the European Ceramic Society (IF. 5.8, top 5%), a top-tier journal in the field of materials science.

- KRISS has become Korea’s first institute confirming the finestructure of ‘magnon,’ a promising material for neuromorphic devices.

- The microscale connection of magnons directly affects device performance. The results present a new milestone in the development of relevant devices.

A Korean research team has succeeded in securing a basic technology for further improving the completeness level of neuromorphic devices.

▲ KRISS Quantum Magnetic Sensing Group

((Clockwise from the left of the back row) Visiting Researcher Kyongmo AN; Senicor Researcher Kim, Changso; Principal Researcher Moon, Kyoung Woong; and Principal Researcher Hwang, Chan Yong)

The Korea Research Institute of Standards and Science (KRISS, President: Lee, Ho Seong) announced that it has become Korea’s first institute observing the finestructure of magnon*, which is attracting attention as a key material for neuromorphic devices. As areas that are approximately 1,000 times finer than before were observed successfully, it is expected that the observation results will enable the design of more sophisticated neuromorphic devices.

*Magnon: A wave that is generated when quantum spins (a characteristic of electrons with magnetic properties) in magnetic materials influence each other. Just as when one domino block falls, the others fall in turn, when energy is applied to one spin, the energy is transferred to the other spins in a ripple-like manner.

Neuromorphic devices are next-generation semiconductors designed to mimic the structure of the human brain. They process information by mimicking the way neurons generate signals and transmit them to other neurons through synapses. Unlike classical semiconductors where data processing devices and storage devices exchange information with each other, neuromorphic devices perform both data storage and processing simultaneously, allowing for rapid processing of massive amounts of information with little power. This is why neuromorphic devices are considered an innovative technology that will drastically reduce the power consumption of artificial intelligence (AI), which has been rapidly increasing recently.

Magnons are a promising material for implementing neuromorphic devices. This is because they are capable of simultaneously sending multiple signals at ultra-low power by utilizing their unique characteristics of transmitting energy to other spins in a ripple-like manner when energy is applied to one quantum spin. However, with the existing level of technology, only a few areas with large bandwidths in the entire structure of magnons can be investigated; therefore, the implementation of high-performance magnon-based neuromorphic devices devices has been limited.

▲ VNA equipment (left) and the magnon device (right) used by the research group to observe the magnon microstructure

The KRISS Quantum Magnetic Sensing Group has become Korea’s first research group that observed the entire structure of magnons in the frequency domain. Using VNA* equipment, the research group discovered that numerous fine frequency structures are present around the previously known frequency domain of magnons. The research group was able to confirm the entire structure of magnons by transmitting electric signals and analyzing the reflected and penetrated spectrum.

* Vector network analyzer (VNA): Equipment that measures the frequency response characteristics (S-parameters) of electronic circuits or materials. By measuring the amplitude and phase change of the signal output when a specific frequency is input, the characteristics of the material can be analyzed. The research group successfully observed the hidden finestructure of magnons by using the frequency offset function, which is a special function of the VNA equipment.

▲ Magnon finestructure observation data analyzed by the KRISS research group

Magnons are typcially measured in the gigahertz (GHz) range. The newly found fine structure of magnons in the megahertz (MHz) range can enhance their functionality. Just as the stronger the connections between neurons, the more active the brain becomes, it is expected that finely adjusting the frequency of magnons will allow for more sophisticated design of neuromorphic devices, further enhancing their performance.

In particular, the magnon observation technology used by the research group in this study is expected to be widely used in research and development of related devices, because it is an electrical method that is faster and simpler than the conventional optical method of converting photon signals in a specific area.

Kyongmo AN, a visiting researcher of KRISS’s Quantum Magnetic Sensing Group, said, “In addition to neuromorphic devices, magnons are also drawing attention as a material for implementing quantum spin qubits, quantum ultra-high-speed networks, and next-generation high-precision sensors.” He added, “We will accelerate the development of application devices based on the structure of the magnons found through our study.”

This research result was supported by the Sejong Science Fellowship Grant Program of the Ministry of Science and ICT and was published in August in the internationally renowned journal, Nature Communications (IF: 14.7).

KRISS Has Developed International Standards for Sunscreen Toxicity Assay with NIST

- A phototoxicity analysis technology has been developed for nanomaterials used in UV-blocking cosmetics 

- The method has been listed as an international standard test method and is expected to increase the safety of cosmetics on the market

The Korea Research Institute of Standards and Science (KRISS, President: Lee, Ho Seong) has developed a safety evaluation technology for nanoparticles* used in UV-blocking cosmetics and has listed it as an international standard.

 * Nanoparticles: Particles with a diameter of 1 to 100 nm (nanometers; 1 nm is about one 100,000th of the hair thickness). Thanks to its tiny size, nanoparticles have superior physical and chemical properties to existing materials.

▲ over page of the new international standard ISO 4962 (In vitro acute nanoparticle phototoxicity assay) developed by the KRISS-NIST joint research team

The ‘acute nanoparticle phototoxicity* assay’ method, jointly developed by the KRISS Nanobiometry Group and the U.S. National Institute of Standards and Technology (NIST), has been adopted as the international standard for nanotechnology (ISO 4962). With the establishment of an international standard that manufacturers and testing institutions around the world can trust and follow, it is expected that consumers will be able to use safer cosmetics.

* Phototoxicity: A phenomenon in which a specific substance causes a toxic reaction in living tissue when exposed to light.

The UV-blocking cosmetics we use contain nanoparticles such as zinc oxide (ZnO), titanium dioxide (TiO2), and silicon dioxide (SiO2). Zinc oxide and titanium dioxide block UV rays, and silicon dioxide improves the texture of cosmetics.

However, these nanoparticles generate reactive oxygen species (ROS) when reacting with ultraviolet rays. ROS attacks living tissues and causes skin diseases with its strong oxidizing power. Therefore, to minimize the negative effects of cosmetics on the skin, the phototoxicity that occurs when nanoparticles react with UV rays must be accurately measured and improved before commercialization.

The problem is that to date, there has been no standardized test method for measuring the phototoxicity of nanoparticles. There was a method proposed by the OECD (OECD 432); however, this test method was developed for completely soluble chemicals and is difficult to apply to insoluble nanoparticles.

 ▲ Measurement process of ISO 4962 (In vitro acute nanoparticle phototoxicity assay)

The ISO 4962 test method, developed by a joint research team of KRISS and NIST and approved as an international standard, is a standardized assay method for measuring the phototoxicity of nanoparticles according to UV exposure. According to this method, cultured skin cells are directly exposed to nanoparticles and then the viability of the skin cells is measured by irradiating UV rays at 10-minute intervals.

With the establishment of this internationally recognized testing methods, the safety of UV-blocking cosmetics is expected to increase significantly. Manufacturers can improve the phototoxicity and side effects of developed products through preliminary testing, and testing institutions can effectively manage the hazards of marketed cosmetics on the human body.

▲ Principal Researcher Lee, Tae Geol (left) and Principal Researcher Heo, Min Beom (right) of KRISS are measuring the phototoxicity of nanoparticles

In addition, as the safety regulations in global cosmetics markets such as the U.S. and China are gradually strengthened, it is expected that this new testing method will serve as a guide for Korea’s cosmetics companies to ensure safety that meets international standards.

Meanwhile, KRISS and NIST have been conducting research cooperation for the development of measurement technology in the field of nano-safety in accordance with the ‘Korea-US Joint Committee on Science and Technology Cooperation’ agreement in 2014. In 2019, through joint research, ‘Measurement method for photocatalytic activity of nanomaterials’ was listed as an international standard (ISO/TC 229), and as a result of steadily expanding international cooperation research, they achieved the feat of listing their second international standard.

Principal Researcher Heo, Min Beom of the KRISS Nanobio Measurement Group said, “In the future, we will establish reliable evaluation criteria so that nanomaterials can be safely used not only in cosmetics but also in various fields of industry and society.”

This research was supported by the Measurement Standards and International Certification System Establishment Research Project for Setting National Nano-Safety Standards funded by the Ministry of Science and ICT.

One Step Closer to Green Hydrogen Era: 

New Material Boosts Production Efficiency and Reduces Costs

- KRISS develops high-performance catalysts for anion exchange membrane (AEM) water electrolysis -

- Affordable and efficient non-precious metal catalyst applicable to alkaline saline water -

# Green hydrogen, produced through water electrolysis, is a next-generation eco-friendly energy source as it does not generate pollutants like carbon dioxide during production. Catalysts play a crucial role in the water electrolysis process, splitting water into hydrogen and oxygen. The efficiency of green hydrogen production largely depends on the performance of these catalysts. Therefore, the commercialization of green hydrogen hinges on the development of cost-effective catalysts capable of maintaining high performance over extended periods.

▲ Researchers behind the development of catalysts for Anion Exchange Membrane (AEM) water electrolysis

                            (From left: Dr. Jun Sang Eon, postdoctoral researcher, Seoul National University; Dr. Park Sun Hwa, Principal Researcher, KRISS;

                                                 Dr. Kwon Ki Chang, Senior Researcher, KRISS; Dr. LEE SOO HEYONG, Principal Researcher, KRISS)

Researchers in Korea have successfully developed a new material that significantly enhances the efficiency of green hydrogen production while reducing costs.

The Korea Research Institute of Standards and Science (KRISS) has developed a high-performance base metal catalyst for use in anion exchange membrane (AEM) water electrolysis.* The newly developed catalyst is not only more affordable than precious metal-based alternatives but also exhibits superior performance, bringing the commercialization of green hydrogen a step closer.

* AEM Water Electrolysis: Among various water electrolysis methods, AEM electrolysis is drawing attention as a next-generation technology. It theoretically allows the use of cost-effective non-metallic catalysts to produce large quantities of hydrogen.

Currently, AEM water electrolysis systems predominantly rely on precious metal catalysts such as platinum (Pt) and iridium (Ir). However, the high cost of these materials and their susceptibility to degradation significantly increase the cost of hydrogen production. To overcome this challenge, the development of durable and affordable base metal catalysts is essential.

▲ Catalysts for AEM water electrolysis developed by KRISS

The KRISS Emerging Material Metrology Group has succeeded in developing base metal catalysts by introducing a small amount of ruthenium (Ru) into a molybdenum dioxide with nickel molybdenum (MoO2-Ni4Mo) structure. While molybdenum dioxide offers high electrical conductivity, its use as a water electrolysis catalyst has been limited due to degradation in alkaline environments.

Through comprehensive structural analysis, the researchers identified hydroxide ion (OH-) adsorption on molybdenum dioxide as the primary cause of degradation. Building on these findings, they devised a method to incorporate ruthenium at an optimal ratio to prevent molybdenum dioxide degradation. The resulting ruthenium nanoparticles, measuring less than 3 nanometers, form a thin layer on the catalysts' surface, preventing degradation and enhancing durability.

Performance evaluations revealed that the newly developed catalysts offers four times the durability and more than six times the activity compared to existing commercial materials. Moreover, when integrated with a perovskite-silicon tandem solar cell, the catalysts achieved a remarkable solar-to-hydrogen efficiency of 22.8%, highlighting its strong compatibility with renewable energy sources.

The catalysts also demonstrated high activity and stability in saline water, producing high-quality hydrogen. This capability is expected to significantly reduce the costs associated with desalination.

▲ A researcher operating the water electrolysis system using the newly developed catalysts

Dr. Sun Hwa Park, a principal researcher at the KRISS Emerging Material Metrology Group, commented, “Currently, producing green hydrogen requires purified water, but using actual seawater could substantially lower costs associated with desalination. We plan to continue our research in this area.”

This research was supported by the KRISS MPI Lab Program and conducted in collaboration with Professor Ho Won Jang’s team at Seoul National University and Dr. Sung Mook Choi’s team at the Korea Institute of Materials Science. The findings were published in the July edition of Applied Catalysis B: Environmental and Energy (IF: 20.2), a leading journal in the field of chemical engineering.

- KRISS Develops High-Quality Compound Semiconductor Material for SWIR Sensors -

- Promising Candidate for Commercialization with Enhanced Detection Range and Reliability Compared to Existing Materials -

# Infrared sensors detect light in wavelengths invisible to the human eye and convert it into electrical signals, uncovering information previously beyond reach. Within the infrared spectrum, short-wave infrared (SWIR), covering wavelengths of 1.4–3.0 micrometers (μm), excels at penetrating smoke and fog while identifying unique spectral signatures of objects. These characteristics make SWIR indispensable for advanced industrial applications, including autonomous vehicle cameras and smart IoT sensors, where it acts as the system's 'eyes.'

The Korea Research Institute of Standards and Science (KRISS, President Ho Seong Lee) has successfully developed a high-quality compound semiconductor material for ultra-sensitive SWIR sensors.

▲ KRISS Semiconductor and Display Metrology Group

(left) principal researcher Byong Sun Chun ; (right) principal researcher Sang Jun Lee

SWIR sensors deliver clear visual information even in low-light conditions, detecting both infrared reflected off objects and that emitted directly by them. While traditionally used in military equipment such as night vision devices, SWIR sensors are now expanding into diverse fields, including autonomous vehicles, semiconductor process monitoring, and smart farm cameras for plant growth observation.

In infrared sensors, the semiconductor material plays a critical role in detecting light signals and converting them into electrical signals. SWIR sensors designed for advanced applications typically employ compound semiconductors—materials composed of two or more elements—due to their significantly higher electron mobility compared to single-element silicon semiconductors. This enhanced mobility allows for the detection of faint light signals with superior energy efficiency.

Currently, indium gallium arsenide (InGaAs), grown on an indium phosphide (InP) substrate, is the most commonly used compound semiconductor material for SWIR sensors. However, InGaAs-based materials face challenges such as lattice mismatch* during fabrication and intrinsic material limitations, which hinder the development of high-performance SWIR sensors.

* Errors that occur due to differences in the lattice structures of elements when depositing thin films in compound semiconductors. These errors generate unnecessary dark current, affecting the material's performance.

KRISS has addressed these challenges by developing a new indium arsenide phosphide (InAsP) material, grown on an InP substrate as the light-absorbing layer. Compared to InGaAs, InAsP exhibits lower noise-to-signal ratios at room temperature, improving reliability. Additionally, its detection range has been expanded from 1.7 μm to 2.8 μm without any loss in performance.

The key innovation lies in the introduction of a metamorphic (lattice relaxation) layer to mitigate lattice mismatch. The research team incorporated a metamorphic structure that gradually adjusts the ratio of As and P between the substrate and the light-absorbing layer. This structure serves as a buffer, preventing direct interaction between materials with differing lattice properties. As a result, lattice strain is significantly reduced, ensuring high material quality and enabling flexible bandgap adjustments.

* Bandgap: The energy gap between the states where electrons exist and do not exist. A wider bandgap indicates superior electron mobility and reduced defect density.

Sang Jun Lee, Principal Researcher at the KRISS Semiconductor and Display Metrology Group, stated, “Given the challenges in importing compound semiconductor materials, which are classified as national strategic resources, it is imperative to secure independent technologies. The material we have developed is ready for immediate commercialization and is expected to be widely applied in emerging industries, including fighter jet radar systems, pharmaceutical defect inspection, and plastic recycling processes.”

This research was supported by the Ministry of Science and ICT’s Core Technology Development Program for Next-Generation Compound Semiconductors and was published in the esteemed journal Advanced Functional Materials (IF: 19) in February.

○ High-Efficiency Multiple Quantum Well LEDs for the Short-Wave Infrared Region

The research team developed InAsPSb, which provides significantly stronger electron and hole confinement compared to traditional InAsP-based multiple quantum well (MQW) LEDs. This advancement effectively traps charge carriers within the MQW structure, addressing issues of charge leakage and efficiency degradation observed in earlier InAsP-based devices, while ensuring high stability under elevated temperatures. Consequently, LEDs incorporating InAsPSb MQWs demonstrate minimal efficiency droop and stable light-emitting performance, even at high temperatures and high current densities.

To address the significant lattice constant mismatch (approximately 2.0%) between InAsPSb and the InP substrate, the researchers refined the metamorphic lattice relaxation growth technique. This approach effectively suppressed threading dislocations caused by lattice mismatch, enabling the fabrication of defect-free, high-quality LEDs within MQW structures containing InAsPSb. By minimizing the surface roughness of the LED device, the team successfully developed high-quality SWIR light-emitting devices on InP substrates.

With these innovative processes and material advancements, InAsPSb-based LEDs demonstrate significant potential as a groundbreaking solution for various advanced applications requiring high-efficiency infrared emitters. These applications include detection, life science sensors, optical communication, and medical diagnostics. In recognition of its contributions to the development of high-efficiency MQW LEDs, the study was published in Advanced Functional Materials on November 7, 2024.

- In-body drug concentration diagnostic technology developed with Severance Hospital to suppress seizures in epilepsy patients -

- Drug delivery system developed with Seoul National University Hospital to enhance treatment efficacy and prolong duration for retinal diseases -

The Korea Research Institute of Standards and Science (KRISS, President Ho Seong Lee) announced that, through joint research with domestic university hospitals, they have developed an advanced disease diagnosis and treatment system based on nanomaterials.

▲ KRISS Nanobio Measurement Group

(From bottom left: Senior researcher Jin Gyeung Son, principal researcher Hee-Kyung Na, 

principal researcher Tae Geol Lee, post-doc researcher Sunho Joh, PhD student Ahmed M. Elbedwehy)

The KRISS Nanobio Measurement Group, in collaboration with Associate Professor Sang-Guk Lee's team from Severance Hospital, successfully developed a new diagnostic technology for Therapeutic Drug Monitoring (TDM) in epilepsy* patients. This new method is expected to significantly reduce the time and cost of current diagnostics while maintaining accuracy, thereby lowering the overall burden on patients managing their condition.

 * Epilepsy: A chronic neurological disorder characterized by recurrent seizures, commonly known as "seizure disorder."

 ○ The research was published in ACS Nano (Impact Factor: 15.8) in June.

▲ Schematic diagram of nanomaterial-based anti-epileptic drug concentration diagnostic technology developed by KRISS

Many epilepsy patients take anti-epileptic drugs to suppress habitual seizures that occur during daily life. To optimize treatment efficacy and prevent side effects from overdosing, patients must regularly monitor the concentration of these drugs in their body.

Currently, the diagnostic technology used in hospitals to monitor anti-epileptic drug concentration has limitations in terms of accuracy and time. The most common method, immunoassay, suffers from cross-reactions with similar drugs, resulting in lower diagnostic accuracy. Although mass spectrometry, which ionizes samples using electrospray, offers higher accuracy, it is time-consuming and costly, increasing the patient burden.

The team’s nanomaterial-based diagnostic approach has overcame the limitations of mass spectrometry. By introducing a molybdenum ditelluride (MoTe2) and tungsten ditelluride (WTe2) nanosheet mixture into the sample and ionizing it with a laser, they successfully improved both the drug detection speed and sensitivity.

When the team applied this newly developed diagnostic technology to the samples of 120 epilepsy patients, the results showed that reliability was maintained at over 99.9%, while the required time was reduced to one-sixteenth of the original. Additionally, the number of samples that can be analyzed in one session increased more than tenfold, potentially reducing diagnostic costs by half.

Moreover, the KRISS Nanobio Measurement Group, in collaboration with Professor Jeong Hun Kim’s team at Seoul National University Hospital, developed a new drug delivery system to enhance the efficacy and prolong the duration of treatment for neovascular retinal diseases.

 ○ The research was published in Journal of Controlled Release (Impact Factor: 10.5) in July.

▲ Schematic diagram of the drug delivery system for retinal disease treatment developed by KRISS

Most neovascular retinal diseases, including age-related macular degeneration (AMD), diabetic retinopathy (DR), and retinopathy of prematurity (ROP), are caused by an imbalance of reactive oxygen species (ROS) in the eye. Excessive production of ROS triggers oxidative stress, leading to retinal cell damage, vision impairment and eventually to blindness for the advanced cases.

Traditional treatments for neovascular retinal diseases involve injecting anti-VEGF agents like Ranibizumab (Lucentis) or Aflibercept (Eylea) into the vitreous. While these therapies are effective in inhibiting abnormal blood vessel growth, they mainly manage symptoms rather than addressing the root cause, oxidative stress, leaving around a third of AMD patients with limited visual improvement. Additionally, these treatments are expensive and require frequent injections due to their short duration of action, which increases the risk of complications such as hemorrhage and inflammation.

The team developed a novel drug delivery system using mesoporous silica nanoparticles (MSNs) to encapsulate humanin (HN), a small mitochondrial-derived peptide therapy with potent antioxidant properties. HN effectively inhibits oxidative stress, addressing the root cause of retinal damage. Encapsulation within MSNs protects the peptide, ensuring its safe delivery to retinal tissue. The system releases the drug only when oxidative stress is detected, extending its therapeutic efficacy per injection.

KRISS Nanobio Measurement Group’s principal researcher, Tae Geol Lee, remarked, "This achievement is significant as it addresses challenges faced in medical practice through collaboration between a national research institute and domestic university hospitals. We will continue to strive for the development of nanotechnology aimed at safeguarding public health."

- World’s first generation and control of skyrmions at room temperature in a 2D materials -

- Reduced power consumption and maximized quantum effects provide a basis for the development of room-temperature qubits and AI semiconductors -

The Korea Research Institute of Standards and Science (KRISS) has, for the first time in the world, generated and controlled skyrmions at room temperature in a two-dimensional (2D) materials. This achievement reduces power consumption compared to traditional three-dimensional (3D) systems while maximizing quantum effects, making it a core technology for the development of room-temperature quantum computers and AI semiconductors.

▲ Schematic of 2D skyrmion electrical control

A skyrmion is a spin structure arranged in a vortex shape, theoretically reducible to just a few nanometers and capable of moving with very low power. If skyrmions can be freely created and manipulated in reality, it would enable the development of next-generation devices with ultra-low power consumption and high performance. As such, research is being actively conducted in this field.

While previous skyrmion applications have only been explored in 3D magnets, the first report of 2D magnets in 2017 broadened research to include 2D materials.

The advantage of 2D over 3D lies in a smoother surface, akin to ice, which reduces friction (heat) and noise when operating skyrmions, allowing for stable operation with lower power consumption. In addition, skyrmions in 2D are smaller than those in 3D, enhancing quantum phenomena.

▲ Experimental images of electrical control of skyrmions implemented in a 2D system

KRISS succeeded in generating and controlling skyrmions in 2D magnets at room temperature. By applying a very fine voltage and magnetic field to the surface of the magnet, skyrmions were created and then driven in the desired direction with a current.

▲ Comparison of power consumption data between 2D and 3D skyrmions

The experimental results showed that the power consumption for controlling skyrmions in 2D was approximately 1/1000 of that in 3D, and their size was reduced by more than ten-fold, providing significant advantages in terms of stability and speed. Although room-temperature skyrmion Creation in 2D has been reported by the US and China at around the same time, KRISS is the first to succeed in both formation and electrical control.

This success comes about a year after the research team developed a 3D skyrmion transistor last February, advancing the development of next-generation spintronic devices. Notably, this technology maximizes the quantum effects of skyrmions at room temperature. This in turn suggested the potential for realizing room-temperature qubits using skyrmions, thereby addressing some of the limitations of existing quantum computers that operate only in ultra-low temperature environments.

Seungmo Yang, the Senior Research Scientist from the KRISS Quantum Magnetic Sensing Group said, “With the recent advances in AI, the demand for ultra-low power semiconductor devices is increasing. Our skyrmion control technology can contribute to the design of next-generation AI semiconductor devices.”

###

As a national metrology institute (NMI) of Korea founded in 1975, KRISS (Korea Research Institute of Standards and Science) has developed measurement standards technology and played a pivotal role in upgrading Korea’s main industries to the global level.

This research, supported by the Ministry of Science and ICT’s Nano and Material Technology Development Project, was a collaborative effort involving the KRISS Quantum Technology Institute's Quantum Magnetic Sensing Group, Professor Kab-Jin Kim’s research team at KAIST, Professor Changgu Lee’s research team at Sungkyunkwan University, and Dr. Mi-Young Im from Lawrence Berkeley National Laboratory (LBNL). The results were published in the renowned journal Advanced Materials (IF: 29.4) last May.

- KRISS manifests that molecular symmetry can govern crystallization pathways through measuring the structural evolution of solute molecules -

- Controlling the crystallization process enables the creation of desired materials; a new milestone in new material development -

# As the opening of the Korea AeroSpace Administration approaches on the 27th, thorough preparations are being made to welcome the new space era. One such effort is the search for new materials to be used in space environments. Researchers are focusing on the “crystallization of substances.” By accurately observing and understanding the crystallization process of a substance, they can adjust particle arrangements to enhance performance or control the formation process to create desired materials.

The Korea Research Institute of Standards and Science (KRISS) has become the first in the world to observe the structural evolution of solute molecules in extremely supersaturated aqueous solutions, revealing that changes in molecular symmetry impact on the formation of new metastable material phases.

 ? The research findings were published in Nature Communications (IF: 16.6) in April and were selected as an Editor's Highlight.

In the 1890s, the German chemist Wilhelm Ostwald recognized that supersaturated solutions often preferred to transform into metastable intermediate phase rather than thermodynamically stable one during crystallization, called Ostwald’s step rule. Up to date, Various hypotheses have been proposed to explain the origin of this phenomenon, with the leading hypothesis being that changes in the molecular structure of solutes in the solution would be the main factor.

▲ Schematic diagram of multiple crystallization pathways based on changes in molecular symmetry in a supersaturated environment

The experimental verification of the solutes molecular symmetry requires the in-situ measurement of solution structure in highly supersaturated solution. However, in conventional experimental environment, it is very difficult to reach even twice its well-known solubility limit value* .

* The solubility limit of solute is obtained by the maximum concentration of solution without any crystallization at room temperature.

The KRISS Space Metrology Group succeeded in achieving supersaturation levels exceeding 4 times of the characteristic solubility limit value by levitating solution droplet using a self-developed electrostatic levitation device.* They became the first in the world to observe the process where the molecular symmetry of solutes changes, altering the crystallization pathways and forming new material phases.

  * Electrostatic levitation (ESL) system: This ESL system levitates objects by applying an electric field between two electrodes that counteracts the effect of gravity. 

  ESL minimizes the gravitational effects and allows materials to be studied without any contact with a container. Furthermore, ESL technique is a non-contact measurement method that enables accurate measurement of thermophysical properties even in extreme condition. The research group succeeded in reducing the hydration number of molecule, which interfere with molecular structure measurement, to one or two per solute molecule using this device, enabling precise observation of the crystallization process.

▲ Diagram of different crystallization based on the different evolution of molecular symmetry in a supersaturated environment

Senior Research scientist Yong Chan Cho from the KRISS Space Metrology Group stated, "This achievement identifies the key factors in the formation of new material phases and suggests methodologies for forming the desired material phases. It can serve as a new milestone in the development of new materials for extreme environments such as space, and in new material research in the bio and medical fields."

In addition, the research group succeeded in implementing ultra-high-temperature environments exceeding 4,000 K (3,726 °C) using the electrostatic levitation device and precisely measuring the thermal properties of heat-resistant materials such as tungsten (W), rhenium (Re), osmium (Os), and tantalum (Ta). These precise thermal property values for ultra-high-temperature heat-resistant materials, used in space launch vehicles, aircraft engines, and nuclear fusion reactors, are expected to enhance the safety and efficiency of their designs.

 ? The research findings were published in APL Materials (IF: 6.1) in April.

▲ Concept diagram of in-situ synchrotron X-ray scattering experiment and the electrostatic levitation system developed by KRISS

Principal Research Scientist Geun Woo Lee from the Space Metrology Group said, "Using the electrostatic levitation device, we can implement a microgravity environment similar to space to precisely measure the thermophysical properties of materials. Currently, advanced aerospace nations are conducting various experiments on the ground using this device to reduce costs and increase research efficiency."

In the future, the research group plans to establish an integrated measurement platform to precisely measure the properties of materials in extreme environments such as ultra-high temperatures, supersaturation, and ultra-high pressures, based on the electrostatic levitation device.

- Improves usability with a portable design and evaluates 6G antenna performance with distortion-free non-metallic sensors -

- Technology transfer to domestic company completed, accelerating 6G commercialization -

# In April 2019, South Korea ambitiously launched the world's first 5G mobile communication service. While 5G in the 3.5 GHz band was commercialized, the communication quality did not meet consumer expectations. The installation of base stations in the 28 GHz band, which would provide true 5G service, was slow due to profitability concerns. Consequently, the government reclaimed the frequency bands from all three major telecommunications companies last year. As countries around the world prepare for the 6G era, it is time to reflect on the disappointing experiences of 5G commercialization and focus on building the 6G infrastructure.

Korea Research Institute of Standards and Science (KRISS) succeeded in developing domestically produced equipment to evaluate the performance of 6G communication antennas.

As the frequency band increases, communication speed typically improves, but the communication range shortens. Since 6G communication (planned for 7–24 GHz) has a higher frequency band than the current 5G communication (3.5 GHz), antenna-related technologies* are needed to address the issue of shortened communication range.

*Extreme massive multiple-input multiple-output, beamforming technology, reconfigurable intelligent surface technology, etc.

▲ Mobile 6G antenna measurement system developed by KRISS

To ensure the proper functioning of these advanced 6G antennas, accurate performance evaluation is essential. Precise performance measurements can help identify and correct causes of malfunction in the prototype stage, improve quality, and shorten the time to mass production.

The research team from the KRISS Electromagnetic Wave Metrology Group has developed 6G antenna measurement system based on a non-metallic sensor using an optical method.

To evaluate antenna performance, the sensor is placed at a certain distance to measure the electromagnetic waves generated by the antenna. Previously, metallic sensors were used. This caused coupling* effects due to the electromagnetic wave reflection properties of metal, resulting in distorted measurements. This problem was easily resolved by replacing them with non-metallic sensors the size of a grain of rice.

*Coupling: Unwanted signals or disturbances caused by electromagnetic coupling, which increases as the distance between metals decreases.

▲ 6G antenna performance measurement sensor developed by KRISS

The distance between the sensor and the antenna during measurement has decreased from several meters to a few millimeters, with measurement time reduced by more than 1/10. Moreover, unlike previous measurements that required very large, fixed facilities such as anechoic chambers, the measurement equipment developed by KRISS is lightweight, similar in size and weight to a computer tower, making it portable and suitable for use in standard laboratories.

KRISS has transferred this technology to East Photonics Co., Ltd., a company specializing in fiber optic communication and repeaters, for a royalty of KRW 300 million, and a signing ceremony was held on April 8 at the KRISS administrative building.

▲ KRISS principal researchers Young-Pyo Hong (left) and Dong-Joon Lee (right) are testing the performance of a 6G antenna prototype using the new measurement system

Young-Pyo Hong, a principal researcher at KRISS, stated, "Currently, domestic research related to 6G is concentrated only in the materials and components fields, and studies have yet to be conducted on measurement equipment. Learning from the disappointing experiences with 28 GHz 5G communication, we plan to prioritize the establishment of 6G infrastructure, with the development of measurement equipment being a crucial part."

Ho-Joon Seok, president and CEO of East Photonics Co., Ltd., said, "All smartphone and base station antenna measurement equipment is expensive and foreign-made, but commencing now we will take the lead in domesticating 6G antenna measurement equipment in close collaboration with KRISS. Unlike existing measurement equipment, our lightweight and mobile measurement equipment will be a strong point as we steadily plan for commercialization."

- World's first reference material for medical imaging systems expected to improve the accuracy of body fat measurement -

- Improves diagnostic reliability of medical imaging systems, and facilitates multi-center clinical trials involving new drug development -

The Korea Research Institute of Standards and Science (KRISS) has developed the world’s first reference material to improve the accuracy of body fat measurements conducted through MRI and CT scans.

This newly developed reference material for medical imaging systems is an emulsified substance created by mixing water and fat. When inserted into a phantom and applied to medical imaging systems, it can serve as a reference for fat measurement. The principle is to analyze the water content within the reference material to calculate the fat amount.

* Phantom: A tool used to evaluate, analyze, and calibrate the performance of medical imaging systems. It is inserted into equipment instead of the human body, and serves as a reference for measurements, similar to a "dummy" used in automobile crash tests.

▲ Emulsified reference material and phantom developed by KRISS for medical imaging devices

Medical imaging systems like MRI and CT are widely utilized for diagnosing chronic conditions such as fatty liver disease as they can non-invasively assess body fat levels, unlike invasive biopsies.

The issue has been the variability in fat measurement values from medical imaging systems, differing by hospital, manufacturer, and model. Since there are no calibration standards, diagnosis relies on the experience and intuition of physicians, posing challenges for multi-center clinical trials and big data research that require consistent measurements from various imaging systems.

Phantoms that mimic body fat have been introduced and are being used. However, they are unstable because they contain around ten additives, including artificial surfactants, and there is a lack of objective verification procedures for the amount of substances.

The reference material developed by KRISS is free of additives that affect measurement values, ensuring precise fat content measurement. It also offers high stability and homogeneity. This development is the result of collaborative research across three departments within KRISS, integrating chemical water measurement technology and ultrasonic emulsification techniques in the field of medical imaging.

▲ Emulsified reference material applied to MRI device in form of phantom

The newly developed reference material and phantom are expected to be distributed to medical institutions, improving the validity of medical imaging system measurements and the reliability of diagnostic results. In addition, they can serve as reference points for multi-center and multi-device data in clinical trials for new drug development, including obesity treatments. Currently, Siemens Healthineers, the leading company in the domestic MRI market, is utilizing this new technology in research on measuring fat content with MRI equipment.

▲ The photography for the phantom and corresponding PDFF map image

Hyo-Min Cho, principal research scientist of the KRISS Medical Metrology Group, said, "The significance of our interdisciplinary study lies in addressing clinical needs in the medical field. We will continue to contribute to public health by developing technologies that bridge the medical and scientific communities."

Professor Dong Wook Kim from the Department of Radiology at Asan Medical Center, who supported the validation of the reference material, stated, "We will use this reference material in future clinical trials and patient-specific disease diagnosis to obtain more accurate and consistent data."

KRISS plans to conduct follow-up research to distribute additional reference materials with refined concentrations, and contribute to establishing a next-generation performance evaluation system for medical imaging devices based on multi-center data.

###

As a national metrology institute (NMI) of Korea founded in 1975, KRISS (Korea Research Institute of Standards and Science) has developed measurement standards technology and played a pivotal role in upgrading Korea’s main industries to the global level.

This research, supported by the Ministry of Trade, Industry, and Energy's Commercial Reference Materials Development and Distribution Program and KRISS's basic program, was published in the international journal Metrologia (IF: 2.4) in January.

- KRISS develops metamaterial to trap and amplify vibrations in small areas -

- Accelerating the commercialization of “Energy Harvesting” technology to collect and convert wasted vibration energy into electricity -

# Energy Harvesting is a green technology that captures (or “harvests”) wasted energy and converts it into electricity. The ubiquitous vibrations that surround us are one of the promising sources for energy harvesting. In particular, vibration energy harvesting has recently gained significant attention as a next-generation power supply technology because it can generate power consistently, unaffected by weather or terrain conditions.

The Korea Research Institute of Standards and Science (KRISS) has developed a metamaterial that traps and amplifies micro-vibrations in small areas. This innovation is expected to increase the power output of energy harvesting, which converts wasted vibration energy into electricity, and accelerate its commercialization.

Energy harvesting refers to technology that converts wasted energy in the form of heat, light, and vibration into electrical energy. While solar power generation, which utilizes sunlight as its energy source, is commonly used, it poses limitations such as inconsistent output and the inability to generate power under certain weather and terrain conditions.

In contrast, utilizing ubiquitous vibrations as an energy source enables stable power generation without surrounding environmental constraints. This is why vibration energy harvesting continues to gain attention as a future source of power for Internet of Things (IoT) sensors that require a constant 24/7 power supply and wearable medical devices that should measure blood pressure and sugar levels in real time.

▲ Metamaterial developed by KRISS

The main issues impeding vibration energy harvesting are that it has lower power output and higher production costs, making it a poor candidate for practical application. While the amount of power produced is proportional to the magnitude of the harvested vibration, most vibrations we encounter in daily life are tiny. To overcome this significant issue, numerous conversion devices, such as piezoelectric elements, should be installed in multiple locations that are exposed to relatively large vibrations.

The metamaterial developed by KRISS traps and accumulates micro-vibrations within it and amplifies them by more than 45 times. This allows the generation of large-scale electrical power relative to the small number of piezoelectric elements that are utilized. By applying vibration harvesting with the developed metamaterial, the research team has succeeded in generating more than four times more electricity per unit area than conventional technologies.

▲ A conceptual illustration demonstrating the vibration amplification performance of the metamaterial developed by KRISS.

The metamaterial can amplify typically discarded micro-vibrations by more than 45 times

In particular, the newly developed metamaterial has a thin, flat structure roughly the size of an adult’s palm, allowing it to be easily attached to any surface where vibration occurs. As its structure can be easily modified to fit the object to which it will be attached, its range of applications is diverse, from diagnostic sensors that check for damage in high-rise buildings or large bridges to small biosensors that monitor health conditions of individuals.

▲ Metamaterial Development Team

“This research is the first in the world to successfully accumulate and amplify vibrations using a surface metamaterial that temporarily traps vibrations,” said Senior Researcher Lee Hyung Jin of the Acoustics, Ultrasound and Vibration Metrology Group at KRISS.

Senior Researcher Seung Hong Min of the Non-Destructive Metrology Group also expressed his interest, commenting, “Metamaterials can be used to develop next-generation high-precision and high-sensitivity sensors by greatly amplifying ultra-fine vibrations that were difficult to measure with conventional sensors.”

###

As a national metrology institute (NMI) of Korea founded in 1975, KRISS (Korea Research Institute of Standards and Science) has developed measurement standards technology and played a pivotal role in upgrading Korea’s main industries to the global level.

The research was conducted in collaboration with Professor Kim Miso’s research team at the School of Advanced Materials Science and Engineering, Sungkyunkwan University. It was supported by the National Strategic R&D Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, the Basic Science Research Program through a National Research Foundation of Korea grant funded by the Korean Government (MEST), the Korea Ministry of Environment funded by the Project for Developing Innovative Drinking Water and Wastewater Technologies by the Korea Environment Industry & Technology Institute, and the Fundamental Project of KRISS. The findings were published in the international journal Mechanical Systems and Signal Processing(IF: 8.4) in February 2024.

- Development of world’s first organoid culture method using liver cells to accurately assess toxicity of nanomaterials-

- Animal replacement test expected to be introduced more rapidly to safety assessment of nanomaterials and nanomedicine-

The Korea Research Institute of Standards and Science (KRISS) has developed the world’s first organoid culture method capable of accurately assessing human toxicity of nanomaterials. Overcoming the limitations of the conventional culture method, this new technology is expected to bring forward the commercialization of organoid-based safety assessment of nanomaterials and nanomedicine.

An organoid is a miniaturized version of an organ produced by culturing human stem cells in vitro. Since an organoid effectively simulates the human body, organoids are attracting much attention as a means of next-generation toxicity assessment, replacing animal tests; however, they have a drawback: the standardization is difficult due to limitations in the culture method.

▲ The organoid culture method in a floating manner developed by KRISS

In the conventional organoid culture method, cells are embedded in the extracellular matrix and solidified in the shape of a dome to form a three-dimensional structure; then a culture medium is added to culture the cells. In this method, the thickness of the extracellular matrix dome varies at the center and the edge, causing an oxygen supply imbalance. As a result, the organoids fail to grow uniformly; instead, they aggregate in the dome like bubbles and thus are difficult to divide. The biggest problem is that nanomaterials cannot penetrate into the dome, so their impact on the organoids canot be accurately confirmed.

In the newly developed organoid culture method, the extracellular matrix is directly mixed with the culture solution to culture organoids in a floating manner. This method is suitable for commercialization because organoids can be produced in a relatively uniform size and can be easily divided into identical numbers. Uniform preparation and division are essential because high-throughput screening is performed in actual industrial sites by placing a maximum of 1,000 organoids into each container to simultaneously test their reactions to nanomaterials.

Another great benefit of the new method is that, unlike the conventional culture method, the absence of the extracellular matrix dome allows each nanomaterial to reach the organoids. The nanomaterial penetration rate is the same as that in the two-dimensional cell model currently used in industrial sites. The newly developed culture method is the world’s first to allow confirmation of nanomaterial penetration into organoids.

The KRISS’ Nanobio Measurement Group initially cultured organoids for three days using the conventional method. After removing the extracellular matrix dome, they carried out floating culture of the organoids in a culture solution mixed with the extracellular matrix at a concentration of 5% (v/v) to test the toxicity of nanomaterials. The organoids were treated with zinc oxide nanoparticles (ZnO NPs), which are a liver toxic material, and nontoxic gold nanoparticles (AuNPs). The comparison showed that the toxicity of each material could be accurately observed, in contrast to the conventional method.

▲ KRISS researchers are observing nanomaterial penetration into dome-shaped extracellular matrix using dark-field microscope

Ahruem Baek, a senior researcher at KRISS, said, “Based on our results, we will establish standard nanomaterial and nanomedicine safety assessment procedures using organoids, contributing to the advancement of Korea’s nano-industry.”

The results from this study may allow for rapid and accurate safety assessment of nanomaterials and nanomedicine using organoids, contributing to the safe utilization of nanomaterials in various strategic technical fields. Tae Geol Lee, the head of the Nanosafety Metrology Center at KRISS, emphasized, “As the need for animal replacement testing, required by the Ministry of Food and Drug Safety and the US FDA, is continuously growing, it is very meaningful that we have developed the world’s first organoid-based nanomaterial safety assessment technology through convergent and cooperative research with a hospital.”

###

As a national metrology institute (NMI) of Korea founded in 1975, KRISS (Korea Research Institute of Standards and Science) has developed measurement standards technology and played a pivotal role in upgrading Korea’s main industries to the global level.

This study, conducted in collaboration with the CHA University School of Medicine, was supported by the Nanosafety Metrology Center Program and the Science Challenge Convergent R&D Program, funded by the Ministry of Science and ICT, the Commercialization of 3D Multifunction Tissue Mimetics Based Drug Evaluation Platform Program, funded by the Ministry of Trade, Industry & Energy, and the Basic R&D Program, funded by the Korea Research Institute of Standards and Science. The results were published in Nano Letters (IF: 10.8), an internationally renowned journal in nanotechnology, in January.

- Achieves high-performance, low-power, precision optimal measurement in the infrared band with undetected-photon sensing -

- Opens up possibilities for applications in other sensing technologies, including non-destructive measurement of 3-dimensional structures, bio-measurements, and spectroscopic gas sensing -

The Korea Research Institute of Standards and Science (KRISS) has developed a novel quantum sensor technology that allows the measurement of perturbations in the infrared region with visible light by leveraging the phenomenon of quantum entanglement. This will enable low-cost, high-performance IR optical measurement, which previously accompanied limitations in delivering quality results.

When a pair of photons, the smallest unit of light particles, are linked by quantum entanglement, they share an associated quantum state regardless of their respective distance. The recently developed undetected photon quantum sensor is a remote sensor that utilizes two light sources that recreate such quantum entanglement.

An undetected photon (idler) refers to a photon that travels to the target of measurement and bounces back. Instead of directly measuring this photon, the undetected photon sensor measures the other photon of the pair that is linked by quantum entanglement to obtain information about the target.

Quantum sensing based on undetected photons is a nascent technology that has only been realized in the last decade. With the technology still at its early stages, the global research community continues to engage actively in the development race. The undetected photon quantum sensor developed by KRISS is differentiated from previous studies in its core photometric devices, the photodetector and interferometer.

A photodetector is a device that converts light into an electrical signal output. Existing high-performance photodetectors were largely limited in their applications to the visible light bandwidths. While wavelengths in the infrared region are useful for measurements in diverse applications across many fields, there were either no available detectors or only detectors with poor performance. This latest KRISS research has allowed the use of visible light detectors to measure the light states in the infrared band, enabling efficient measurement without requiring costly and power-consuming equipment. It can be used in a wide range of applications, including the non-destructive measurement of three-dimensional structures, biometry, and the analysis of gas compositions.

▲ A composite interferometer experiment device for the undetected photon quantum sensor

Another critical element in precision optical measurement is the interferometer, a device that obtains signals by integrating multiple rays of light that travel through separated paths. Conventional undetected photon quantum sensors mainly use simple Michelson interferometers that adopt simple light paths, restricting the number of targets that can be measured. The sensor developed by KRISS implements a hybrid interferometer that can flexibly change the light paths depending on the target object, greatly improving scalability. Thus, the sensor is suitable for adaptation to various environmental requirements as it can be modified based on the size or shape of the measured object.

The Quantum Optics Group at KRISS has presented a theoretical analysis of the factors that determine the key performance metrics of the quantum sensors and empirically demonstrated their effectiveness by using a hybrid interferometer. The research team reflected light in the infrared band onto a three-dimensional sample to be measured and measured the entangled photons in the visible bandwidth to obtain the sample image, including its depth and width. The team has successfully reconstructed a three-dimensional infrared image from measurements made in the visible range.

▲ Researchers performing optical alignment with the pump laser of the composite interferometer experiment device

Park Hee Su, Head of the Quantum Optics Group at KRISS, said, “This is a breakthrough example that has overcome the limits of conventional optical sensing by leveraging the principles of quantum optics.” He added that KRISS “will continue with follow-up research for the practical application of the technology by reducing its measurement time and increasing sensor resolution.”

###

As a national metrology institute (NMI) of Korea founded in 1975, KRISS (Korea Research Institute of Standards and Science) has developed measurement standards technology and played a pivotal role in upgrading Korea’s main industries to the global level.

This research, led by KRISS in collaboration with KAIST’s Department of Physics, has been supported by the KRISS Project, the Creative Convergence Research Project of the National Research Council of Science & Technology, and by the Quantum Information Science R&D Ecosystem Creation Program of the Ministry of Science and ICT. The research was reported in the January 2024 issue of the international journal Quantum Science and Technology, IF: 6.70.

- Improves usability with a portable design and evaluates 6G antenna performance with distortion-free non-metallic sensors -

- Technology transfer to domestic company completed, accelerating 6G commercialization -

# In April 2019, South Korea ambitiously launched the world's first 5G mobile communication service. While 5G in the 3.5 GHz band was commercialized, the communication quality did not meet consumer expectations. The installation of base stations in the 28 GHz band, which would provide true 5G service, was slow due to profitability concerns. Consequently, the government reclaimed the frequency bands from all three major telecommunications companies last year. As countries around the world prepare for the 6G era, it is time to reflect on the disappointing experiences of 5G commercialization and focus on building the 6G infrastructure.

Korea Research Institute of Standards and Science (KRISS) succeeded in developing domestically produced equipment to evaluate the performance of 6G communication antennas.

As the frequency band increases, communication speed typically improves, but the communication range shortens. Since 6G communication (planned for 7–24 GHz) has a higher frequency band than the current 5G communication (3.5 GHz), antenna-related technologies* are needed to address the issue of shortened communication range.

*Extreme massive multiple-input multiple-output, beamforming technology, reconfigurable intelligent surface technology, etc.

To ensure the proper functioning of these advanced 6G antennas, accurate performance evaluation is essential. Precise performance measurements can help identify and correct causes of malfunction in the prototype stage, improve quality, and shorten the time to mass production.

▲Mobile 6G antenna measurement system developed by KRISS

The research team from the KRISS Electromagnetic Wave Metrology Group has developed 6G antenna measurement system based on a non-metallic sensor using an optical method.

To evaluate antenna performance, the sensor is placed at a certain distance to measure the electromagnetic waves generated by the antenna. Previously, metallic sensors were used. This caused coupling* effects due to the electromagnetic wave reflection properties of metal, resulting in distorted measurements. This problem was easily resolved by replacing them with non-metallic sensors the size of a grain of rice.

*Coupling: Unwanted signals or disturbances caused by electromagnetic coupling, which increases as the distance between metals decreases.

▲6G antenna performance measurement sensor developed by KRISS

The distance between the sensor and the antenna during measurement has decreased from several meters to a few millimeters, with measurement time reduced by more than 1/10. Moreover, unlike previous measurements that required very large, fixed facilities such as anechoic chambers, the measurement equipment developed by KRISS is lightweight, similar in size and weight to a computer tower, making it portable and suitable for use in standard laboratories.

KRISS has transferred this technology to East Photonics Co., Ltd., a company specializing in fiber optic communication and repeaters, for a royalty of KRW 300 million, and a signing ceremony was held on April 8 at the KRISS administrative building.

▲KRISS principal researchers Young-Pyo Hong (left) and Dong-Joon Lee (right) are testing the performance of a 6G antenna prototype using the new measurement system.

Young-Pyo Hong, a principal researcher at KRISS, stated, "Currently, domestic research related to 6G is concentrated only in the materials and components fields, and studies have yet to be conducted on measurement equipment. Learning from the disappointing experiences with 28 GHz 5G communication, we plan to prioritize the establishment of 6G infrastructure, with the development of measurement equipment being a crucial part."

Ho-Joon Seok, president and CEO of East Photonics Co., Ltd., said, "All smartphone and base station antenna measurement equipment is expensive and foreign-made, but commencing now we will take the lead in domesticating 6G antenna measurement equipment in close collaboration with KRISS. Unlike existing measurement equipment, our lightweight and mobile measurement equipment will be a strong point as we steadily plan for commercialization."

- KRISS develops metamaterial to trap and amplify vibrations in small areas -

- Accelerating the commercialization of "Energy Harvesting" technology to collect and convert wasted vibration energy into electricity -

# Energy Harvesting is a green technology that captures (or “harvests”) wasted energy and converts it into electricity. The ubiquitous vibrations that surround us are one of the promising sources for energy harvesting. In particular, vibration energy harvesting has recently gained significant attention as a next-generation power supply technology because it can generate power consistently, unaffected by weather or terrain conditions.

The Korea Research Institute of Standards and Science (KRISS) has developed a metamaterial that traps and amplifies micro-vibrations in small areas. This innovation is expected to increase the power output of energy harvesting, which converts wasted vibration energy into electricity, and accelerate its commercialization.

▲ Metamaterial Development Team

Energy harvesting refers to technology that converts wasted energy in the form of heat, light, and vibration into electrical energy. While solar power generation, which utilizes sunlight as its energy source, is commonly used, it poses limitations such as inconsistent output and the inability to generate power under certain weather and terrain conditions.

In contrast, utilizing ubiquitous vibrations as an energy source enables stable power generation without surrounding environmental constraints. This is why vibration energy harvesting continues to gain attention as a future source of power for Internet of Things (IoT) sensors that require a constant 24/7 power supply and wearable medical devices that should measure blood pressure and sugar levels in real time.

The main issues impeding vibration energy harvesting are that it has lower power output and higher production costs, making it a poor candidate for practical application. While the amount of power produced is proportional to the magnitude of the harvested vibration, most vibrations we encounter in daily life are tiny. To overcome this significant issue, numerous conversion devices, such as piezoelectric elements, should be installed in multiple locations that are exposed to relatively large vibrations.

▲Metamaterial developed by KRISS

▲A conceptual illustration demonstrating the vibration amplification performance of the metamaterial developed by KRISS. The metamaterial can amplify typically discarded micro-vibrations by more than 45 times.

The metamaterial developed by KRISS traps and accumulates micro-vibrations within it and amplifies them by more than 45 times. This allows the generation of large-scale electrical power relative to the small number of piezoelectric elements that are utilized. By applying vibration harvesting with the developed metamaterial, the research team has succeeded in generating more than four times more electricity per unit area than conventional technologies.

In particular, the newly developed metamaterial has a thin, flat structure roughly the size of an adult’s palm, allowing it to be easily attached to any surface where vibration occurs. As its structure can be easily modified to fit the object to which it will be attached, its range of applications is diverse, from diagnostic sensors that check for damage in high-rise buildings or large bridges to small biosensors that monitor health conditions of individuals.

“This research is the first in the world to successfully accumulate and amplify vibrations using a surface metamaterial that temporarily traps vibrations,” said Senior Researcher Lee Hyung Jin of the Acoustics, Ultrasound and Vibration Metrology Group at KRISS.

Senior Researcher Seung Hong Min of the Non-Destructive Metrology Group also expressed his interest, commenting, “Metamaterials can be used to develop next-generation high-precision and high-sensitivity sensors by greatly amplifying ultra-fine vibrations that were difficult to measure with conventional sensors.”

The research was conducted in collaboration with Professor Kim Miso’s research team at the School of Advanced Materials Science and Engineering, Sungkyunkwan University. It was supported by the National Strategic R&D Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science and ICT, the Basic Science Research Program through a National Research Foundation of Korea grant funded by the Korean Government (MEST), the Korea Ministry of Environment funded by the Project for Developing Innovative Drinking Water and Wastewater Technologies by the Korea Environment Industry & Technology Institute, and the Fundamental Project of KRISS. The findings were published in the international journal Mechanical Systems and Signal Processing(IF: 8.4) in February 2024.

- World's first reference material for medical imaging systems expected to improve the accuracy of body fat measurement -

- Improves diagnostic reliability of medical imaging systems, and facilitates multi-center clinical trials involving new drug development -

The Korea Research Institute of Standards and Science (KRISS) has developed the world’s first reference material to improve the accuracy of body fat measurements conducted through MRI and CT scans.

This newly developed reference material for medical imaging systems is an emulsified substance created by mixing water and fat. When inserted into a phantom and applied to medical imaging systems, it can serve as a reference for fat measurement. The principle is to analyze the water content within the reference material to calculate the fat amount.

* Phantom: A tool used to evaluate, analyze, and calibrate the performance of medical imaging systems. It is inserted into equipment instead of the human body, and serves as a reference for measurements, similar to a "dummy" used in automobile crash tests.

▲ Emulsified reference material and phantom developed by KRISS for medical imaging devices

Medical imaging systems like MRI and CT are widely utilized for diagnosing chronic conditions such as fatty liver disease as they can non-invasively assess body fat levels, unlike invasive biopsies.

The issue has been the variability in fat measurement values from medical imaging systems, differing by hospital, manufacturer, and model. Since there are no calibration standards, diagnosis relies on the experience and intuition of physicians, posing challenges for multi-center clinical trials and big data research that require consistent measurements from various imaging systems.

Phantoms that mimic body fat have been introduced and are being used. However, they are unstable because they contain around ten additives, including artificial surfactants, and there is a lack of objective verification procedures for the amount of substances.

▲Emulsified reference material applied to MRI device in form of phantom

▲The photography for the phantom and corresponding PDFF map image.

The reference material developed by KRISS is free of additives that affect measurement values, ensuring precise fat content measurement. It also offers high stability and homogeneity. This development is the result of collaborative research across three departments within KRISS, integrating chemical water measurement technology and ultrasonic emulsification techniques in the field of medical imaging.

The newly developed reference material and phantom are expected to be distributed to medical institutions, improving the validity of medical imaging system measurements and the reliability of diagnostic results. In addition, they can serve as reference points for multi-center and multi-device data in clinical trials for new drug development, including obesity treatments. Currently, Siemens Healthineers, the leading company in the domestic MRI market, is utilizing this new technology in research on measuring fat content with MRI equipment.

Hyo-Min Cho, principal research scientist of the KRISS Medical Metrology Group, said, "The significance of our interdisciplinary study lies in addressing clinical needs in the medical field. We will continue to contribute to public health by developing technologies that bridge the medical and scientific communities."

Professor Dong Wook Kim from the Department of Radiology at Asan Medical Center, who supported the validation of the reference material, stated, "We will use this reference material in future clinical trials and patient-specific disease diagnosis to obtain more accurate and consistent data."

KRISS plans to conduct follow-up research to distribute additional reference materials with refined concentrations, and contribute to establishing a next-generation performance evaluation system for medical imaging devices based on multi-center data.

This research, supported by the Ministry of Trade, Industry, and Energy's Commercial Reference Materials Development and Distribution Program and KRISS's basic program, was published in the international journal Metrologia (IF: 2.4) in January.

- Development of world's first organoid culture method using liver cells to accurately assess toxicity of nanomaterials -

- Animal replacement test expected to be introduced more rapidly to safety assessment of nanomaterials and nanomedicine -

The Korea Research Institute of Standards and Science (KRISS) has developed the world’s first organoid culture method capable of accurately assessing human toxicity of nanomaterials. Overcoming the limitations of the conventional culture method, this new technology is expected to bring forward the commercialization of organoid-based safety assessment of nanomaterials and nanomedicine.

An organoid is a miniaturized version of an organ produced by culturing human stem cells in vitro. Since an organoid effectively simulates the human body, organoids are attracting much attention as a means of next-generation toxicity assessment, replacing animal tests; however, they have a drawback: the standardization is difficult due to limitations in the culture method.

In the conventional organoid culture method, cells are embedded in the extracellular matrix and solidified in the shape of a dome to form a three-dimensional structure; then a culture medium is added to culture the cells. In this method, the thickness of the extracellular matrix dome varies at the center and the edge, causing an oxygen supply imbalance. As a result, the organoids fail to grow uniformly; instead, they aggregate in the dome like bubbles and thus are difficult to divide. The biggest problem is that nanomaterials cannot penetrate into the dome, so their impact on the organoids canot be accurately confirmed.

▲The organoid culture method in a floating manner developed by KRISS

In the newly developed organoid culture method, the extracellular matrix is directly mixed with the culture solution to culture organoids in a floating manner. This method is suitable for commercialization because organoids can be produced in a relatively uniform size and can be easily divided into identical numbers. Uniform preparation and division are essential because high-throughput screening is performed in actual industrial sites by placing a maximum of 1,000 organoids into each container to simultaneously test their reactions to nanomaterials.

Another great benefit of the new method is that, unlike the conventional culture method, the absence of the extracellular matrix dome allows each nanomaterial to reach the organoids. The nanomaterial penetration rate is the same as that in the two-dimensional cell model currently used in industrial sites. The newly developed culture method is the world’s first to allow confirmation of nanomaterial penetration into organoids.

The KRISS’ Nanobio Measurement Group initially cultured organoids for three days using the conventional method. After removing the extracellular matrix dome, they carried out floating culture of the organoids in a culture solution mixed with the extracellular matrix at a concentration of 5% (v/v) to test the toxicity of nanomaterials. The organoids were treated with zinc oxide nanoparticles (ZnO NPs), which are a liver toxic material, and nontoxic gold nanoparticles (AuNPs). The comparison showed that the toxicity of each material could be accurately observed, in contrast to the conventional method.

▲KRISS researchers are observing nanomaterial penetration into dome-shaped extracellular matrix using dark-field microscope.

Ahruem Baek, a senior researcher at KRISS, said, “Based on our results, we will establish standard nanomaterial and nanomedicine safety assessment procedures using organoids, contributing to the advancement of Korea’s nano-industry.”

The results from this study may allow for rapid and accurate safety assessment of nanomaterials and nanomedicine using organoids, contributing to the safe utilization of nanomaterials in various strategic technical fields. Tae Geol Lee, the head of the Nanosafety Metrology Center at KRISS, emphasized, “As the need for animal replacement testing, required by the Ministry of Food and Drug Safety and the US FDA, is continuously growing, it is very meaningful that we have developed the world’s first organoid-based nanomaterial safety assessment technology through convergent and cooperative research with a hospital.”

This study, conducted in collaboration with the CHA University School of Medicine, was supported by the Nanosafety Metrology Center Program and the Science Challenge Convergent R&D Program, funded by the Ministry of Science and ICT, the Commercialization of 3D Multifunction Tissue Mimetics Based Drug Evaluation Platform Program, funded by the Ministry of Trade, Industry & Energy, and the Basic R&D Program, funded by the Korea Research Institute of Standards and Science. The results were published in Nano Letters (IF: 10.8), an internationally renowned journal in nanotechnology, in January.

 - Achieves high-performance, low-power, precision optimal measurement in the infrared band with undetected-photon sensing -

- Opens up possibilities for applications in other sensing technologies, including non-destructive measurement of 3-dimensional structures, bio-measurements, and spectroscopic gas sensing -

The Korea Research Institute of Standards and Science (KRISS) has developed a novel quantum sensor technology that allows the measurement of perturbations in the infrared region with visible light by leveraging the phenomenon of quantum entanglement. This will enable low-cost, high-performance IR optical measurement, which previously accompanied limitations in delivering quality results.

When a pair of photons, the smallest unit of light particles, are linked by quantum entanglement, they share an associated quantum state regardless of their respective distance. The recently developed undetected photon quantum sensor is a remote sensor that utilizes two light sources that recreate such quantum entanglement.

An undetected photon (idler) refers to a photon that travels to the target of measurement and bounces back. Instead of directly measuring this photon, the undetected photon sensor measures the other photon of the pair that is linked by quantum entanglement to obtain information about the target.

Quantum sensing based on undetected photons is a nascent technology that has only been realized in the last decade. With the technology still at its early stages, the global research community continues to engage actively in the development race. The undetected photon quantum sensor developed by KRISS is differentiated from previous studies in its core photometric devices, the photodetector and interferometer.

A photodetector is a device that converts light into an electrical signal output. Existing high-performance photodetectors were largely limited in their applications to the visible light bandwidths. While wavelengths in the infrared region are useful for measurements in diverse applications across many fields, there were either no available detectors or only detectors with poor performance. This latest KRISS research has allowed the use of visible light detectors to measure the light states in the infrared band, enabling efficient measurement without requiring costly and power-consuming equipment. It can be used in a wide range of applications, including the non-destructive measurement of three-dimensional structures, biometry, and the analysis of gas compositions.

▲ A composite interferometer experiment device for the undetected photon quantum sensor

Another critical element in precision optical measurement is the interferometer, a device that obtains signals by integrating multiple rays of light that travel through separated paths. Conventional undetected photon quantum sensors mainly use simple Michelson interferometers that adopt simple light paths, restricting the number of targets that can be measured. The sensor developed by KRISS implements a hybrid interferometer that can flexibly change the light paths depending on the target object, greatly improving scalability. Thus, the sensor is suitable for adaptation to various environmental requirements as it can be modified based on the size or shape of the measured object.

The Quantum Optics Group at KRISS has presented a theoretical analysis of the factors that determine the key performance metrics of the quantum sensors and empirically demonstrated their effectiveness by using a hybrid interferometer. The research team reflected light in the infrared band onto a three-dimensional sample to be measured and measured the entangled photons in the visible bandwidth to obtain the sample image, including its depth and width. The team has successfully reconstructed a three-dimensional infrared image from measurements made in the visible range.

▲ Researchers performing optical alignment with the pump laser of the composite interferometer experiment device

Park Hee Su, Head of the Quantum Optics Group at KRISS, said, “This is a breakthrough example that has overcome the limits of conventional optical sensing by leveraging the principles of quantum optics.” He added that KRISS “will continue with follow-up research for the practical application of the technology by reducing its measurement time and increasing sensor resolution.”

This research, led by KRISS in collaboration with KAIST’s Department of Physics, has been supported by the KRISS Project, the Creative Convergence Research Project of the National Research Council of Science & Technology, and by the Quantum Information Science R&D Ecosystem Creation Program of the Ministry of Science and ICT. The research was reported in the January 2024 issue of the international journal Quantum Science and Technology, IF: 6.70.

- New hybrid nano-microscope by KRISS allows simultaneous measurement of optical and electrical properties -

- Expected to accelerate nano-scale research on advanced equipment and materials such as bilayer graphene -

The Korea Research Institute of Standards and Science (KRISS, President Dr. Ho Seong Lee) has developed a hybrid nano-microscope capable of simultaneously measuring various nano-material properties. This nano-microscope is essential for researching the properties of nano-composite materials and is also suitable for commercialization. It is expected to promote the development of industries for related materials and equipment.

▲ KRISS research team

The newly developed microscope is a hybrid nano-microscope combining the functions of atomic force microscopy, photo-induced force microscopy, and electrostatic force microscopy. Instead of using lenses, it employs a fine functional probe to tap the sample, allowing simultaneous measurement of the optical and electrical properties as well as the shape of nano-materials with a single scan.

The bilayer graphene is one of the typical nano-materials that benefit from using the hybrid nano-microscope. It has great potential for applications because of its superior mechanical strength, flexibility, and high thermal conductivity compared to monolayer graphene. Depending on the voltage applied to each layer or the twisted angle between two layers, the bilayer graphene exhibits various properties, including superconductivity.

▲ Hybrid nano-microscope developed by KRISS

▲ Schematic diagram of hybrid nano-microscope

The KRISS Material Property Metrology Group has elucidated the principles of the unique infrared absorption response observed in bilayer graphene with the hybrid nano-microscope. The KRISS researchers confirmed that this phenomenon is caused by the charge imbalance between the two layers of graphene. They also experimentally demonstrated the ability to control infrared absorption through intentionally inducing and adjusting the charge imbalance.

Conventional nano-microscopes could only measure a single property of a material at a time, making it challenging to measure and analyze composite properties. Although there were some cases of measuring two properties simultaneously, its commercialization was still restrictive because it was demanding to manufacture the equipment.

The novel nano-microscope developed by KRISS can be easily applied to industrial settings as it can be manufactured without significant changes to the structure of the existing atomic force microscope. The KRISS research team, therefore, is the first to develop a hybrid nano-microscope that can be commercialized.

By expanding its measurement properties to the magnetic properties besides the optical and electrical properties, it will be possible to observe all three properties simultaneously on the nano-scale. This is expected to accelerate research on the properties of various nano-composite materials, including quantum materials, contributing to the development of nano-materials, parts, and equipment.

▲ Hybrid nano-imaging results of bilayer graphene

Another strength of this technology is the ability to induce localized changes in properties. By using the microscopic probe to scratch the sample surface and adjusting the amount of applied electrons, it is possible to simultaneously control the optical and electrical properties of the component like a switch. This can be useful for the design of circuits and sophisticated devices applying composite properties.

Dr. Eun Seong Lee, a principal researcher from the KRISS Material Property Metrology Group, said, “This achievement is the culmination of our research experience in nano-measurement since 2015. We hope to secure a leading position in the research on new materials by developing nano-measurement technology for composite properties.”

The results of this study, supported by the Fundamental Project of KRISS and the Outstanding Young Scientist Research Program as well as the Nanosafety Technology Support Program by the Ministry of Science and ICT, were published online in Light: Science & Applications (IF: 20.257) in November 2023. Technology transfer and applications for overseas patents are also underway.

- Mechanism behind fibrosis shows that controlling the microenvironment of biological tissues can promote wound healing and regeneration -

- Expected to contribute to the development of wound healing medication and research on fibrotic diseases and cancer -

The Korea Research Institute of Standards and Science (KRISS, President Dr. Ho Seong Lee) has unveiled a new principle for controlling the microenvironment of biological tissues to promote wound healing and regeneration. This discovery holds significant promise for the development of wound healing medication as well as research on fibrotic diseases and cancer.

▲ KRISS research team

The KRISS Nanobio Measurement Group elucidated the mechanism of fibrosis in wound healing and regeneration through research using skin cells. In addition, they proposed a method of mechanically controlling the microenvironment of biological tissues surrounding wounds to regulate fibrosis at the local level.

Fibrosis is a phenomenon in which the extracellular matrix surrounding cells secretes substances such as collagen, leading to the stiffening of biological tissues. One of the typical examples is the formation of scar tissue in wounds. When this occurs normally, it plays a crucial role in wound healing and regeneration. However, excessive fibrosis can lead to conditions where organs, such as the liver, lungs, and heart, become rigid or can result in autoimmune diseases such as scleroderma.

Fibrosis occurs as fibroblasts differentiate into myofibroblasts. To control fibrosis, therefore, it is essential to understand the conditions within the body that trigger this differentiation.

According to the KRISS research team’s observation using optical microscopy, fibroblast differentiation is most active when the elastin content of the skin extracellular matrix reaches 20 %. The normal level of elastin is 10 %, and an increase in this value enhances the elasticity of biological tissue. The results validate the importance of compositional changes in the surrounding microtissues for controlling fibrosis.

▲ Analysis results of the cellular microenvironment where fibrosis occurs

▲ Mechanism of wound healing elucidated through control of the microenvironment

Furthermore, the research team identified proteins involved in regulating the elasticity of biological tissues using the high-precision protein analysis and proved that regulating these proteins can promote fibroblast differentiation through experiments.

Conventional research on fibrosis control has employed chemical methods, which is adding growth factors such as EGF to cells to promote fibroblast differentiation. In contrast, the new accomplishment by KRISS involves changing the elasticity of biological tissues in the local area to regulate fibroblast differentiation. This is considered safer than the previous method as it prevents unexpected chain reactions that growth factors might induce within cells.

▲ KRISS researchers are performing nonlinear optical imaging.

This achievement was made by the integration of KRISS's unique technologies for nonlinear optical imaging and protein analysis. Nonlinear optical imaging technology enables the observation of collagen within samples without staining, which prevents the damage to minute samples during the staining process. Protein analysis technology, which is for the accurate quantification of proteins present in biological samples, provides information on cellular proteins based on elastin content.

This achievement can be applied not only to the development of supplemental medication for wound healing by controlling the cellular microenvironment but also to additional research on treatments for related diseases such as liver fibrosis, lung fibrosis, and heart fibrosis. Since the quantity of elastin is known to influence the proliferation of cancer cells, the findings are also expected to contribute to research on controlling cancer growth.

▲ KRISS researchers are analyzing changes in biological tissues.

Dr. Se Hwa Kim, a principal researcher from the KRISS Nanobio Measurement Group, stated, “The convergence of advanced bio-measurement technologies by KRISS led to this achievement. We plan to expand research into various fibrosis mechanisms using organ cells as well as skin cells.”

The results of this study, supported by the Fundamental Project of KRISS, the Nano Material Technology Development Program of the Ministry of Science and ICT, as well as the Postdoctoral Fellowship Program for Young Scientists of the National Research Council of Science & Technology, were published online in the international journal Biomaterials Research (IF: 15.86) in October 2023.

- Pipeline damage prevention system enables early warning by detecting the timing and location of the damage -

- Field validation and technology transfer completed; useful for smart monitoring of water, gas, oil, and heat pipelines -

The Korea Research Institute of Standards and Science (KRISS, President Dr. Ho Seong Lee) has developed a damage prevention and early detection system for buried pipelines, preventing pipeline failures caused by third-party interference (TPI) and other threats.

▲ The KRISS research team

TPI is one of the main causes of damage to buried pipelines used for transporting water, petroleum, gas, and other substances. Leaks in damaged pipelines not only lead to environmental contamination but also present risks such as explosions, fires, and sinkholes. However, the prevention still has been challenging for pipeline management entities to detect TPI in advance.

The Non-Destructive Metrology Group at KRISS has developed a real-time monitoring system that identifies actual damage activities before buried pipelines are damaged. When TPI or other threats make a critical impact just around pipelines, the system recognizes it as a risk and gives early warnings to prevent incidents.

▲ Scenario for damage prevention and early detection system for buried pipelines

The core technology is based on precise measurement and analytical models of the elastic wave propagated upon impact to the pipelines. With a pair of sensors several hundred meters apart along the pipeline, the system enables the real-time monitoring of impact signals between the sensors. This provides immediate calculation of the time and location of the impact, similar to seismological centers that detect vibrations and localize source position of an earthquake using arrival time of seismic waves.

▲ Sensors attached to buried pipelines

The sensors can be easily attached to accessible parts exposed from buried pipelines, such as valve chambers or manholes. Moreover, the system incorporates precise analytical algorithms that effectively reduce and filter out unnecessary signals like noise from surroundings: traffic, daily life noise, and so on.

▲ Results of damage analysis and source location

The research team conducted tremendous field experiments to validate the system's practical applicability to real buried pipelines in operation spanning several kilometers in South Korea. The results demonstrated that the system successfully detected impacts over about 20 kN with an accuracy of over 95 %. Given that typical force causing pipeline damage often in the range of several hundreds kN or more, the system was found to be suitable for the prevention and early warning of pipeline damage incidents.

Conventional monitoring technologies for buried pipelines usually have only focused on detecting leaks after damages occur. This accomplishment by KRISS, therefore, represents the world’s first early detection system for long-distance pipeline damage. The research team completed technology transfers to companies in South Korea and filed patent applications in both the United States and Europe.

The novel system can be applied not only to water pipelines but also to various types of pipelines, including those for oil and gas transportation as well as heat supply. It can be utilized in smart monitoring systems for the online detection and management of abnormal conditions in buried pipelines.

▲ The KRISS team is generating virtual pipeline impact signals for measurement and analysis.

Dr. Dong-Jin Yoon, a principal researcher from the Non-Destructive Metrology Group, said, “Despite the serious risk of major accidents and loss of life due to pipeline breaks, we have had to rely on leakage reports from informants. This technology will contribute to public safety and social cost savings.”

The results of this study, funded by the Advanced Water Management Research Project of the Ministry of Environment, the Fundamental Project of KRISS, and the Innopolis Promotion Project of the Ministry of Science and ICT, has been published in four international journals, including the August issue of Structural Health Monitoring (IF: 6.6).

- KRISS develops a sensor with advanced materials for monitoring nitrogen dioxide in the atmosphere with the world’s highest sensitivity -

- With high efficiency in time and cost, it can be applicable to research on atmospheric conditions and various sensors/catalysts -

The Korea Research Institute of Standards and Science (KRISS, President Dr. Ho Seong Lee) developed a toxic gas sensor with the world's highest sensitivity. This sensor can precisely monitor nitrogen dioxide (NO2), a toxic gas in the atmosphere, at room temperature with low power consumption and ultra-high sensitivity. It can be applied to diverse fields, such as detection of residual gases during semiconductor manufacturing process and research on electrolysis catalysts.

▲ The KRISS research team

NO2, produced by the high-temperature combustion of fossil fuels and primarily emitted through automobile exhaust or factory smoke, contributes to an increase in mortality due to air pollution. In South Korea, the annual average concentration of NO2 in the air is regulated to be 30 ppb* or lower by presidential decree. Highly sensitive sensors, therefore, are required to accurately detect gases at extremely low concentrations.

* ppb: parts per billion

In recent times, the use of toxic gases which are potentially fatal to humans has been on the rise due to the development of high-tech industries, including semiconductor manufacturing. While some laboratories and factories have adopted semiconductor-type sensors for safety, the challenge lies in their low response sensitivity, making them unable to detect toxic gases that may even be perceptible to the human nose. To increase the sensitivity, they consume a lot of energy in the end because they must operate at high temperatures.

▲ Materials for the ultra-sensitive gas sensor developed by KRISS

(left) Synthetic target substrate (Si/SiO2), (center) 3D MoS2 nano-branch advanced material, (right) ultra-sensitive gas sensor

The newly developed sensor, a next-generation semiconductor-type toxic gas sensor based on advanced materials, exhibits significantly improved performance and usability compared to conventional sensors. With its outstanding sensitivity to chemical reactions, the new sensor can detect NO2 much more sensitively than previously reported semiconductor-type sensors, a sensitivity that is 60 times higher. Moreover, the novel sensor consumes minimal power operating at room temperature, and its optimal semiconductor manufacturing process enables large-area synthesis at low temperatures, thereby reducing fabrication costs.

▲ Performance evaluation results of the ultra-sensitive gas sensor developed by KRISS

(a), (b): Measurement results of NO2 with different concentrations demonstrate excellent measurement resolution.

(c): Consistent measurement results were observed when the measurement of NO2 with the same concentration was repeated, which indicates high reproducibility and measurement reliability.

(d): The sensor exhibited excellent ability to selectively detect NO2 among several interference gases.

The key to the technology lies in the MoS2 nanobranch material developed by KRISS. Unlike the conventional 2D flat structure of MoS2, this material is synthesized in a 3D structure resembling tree branches, thereby enhancing the sensitivity. Besides its strength of uniform material synthesis on a large area, it can create a 3D structure by adjusting the carbon ratio in the raw material without additional processes.

▲ Tidal process for creating 3D MoS2 nano-branches

The structural transformation of MoS2 into a 3D tree- branch shape can be observed over the synthesis time.

The KRISS Semiconductor Integrated Metrology Team has experimentally demonstrated that their gas sensor can detect NO2 in the atmosphere at concentrations as low as 5 ppb. The calculated detection limit of the sensor is 1.58 ppt**, marking the world's highest level of sensitivity.

** ppt: parts per trillion

This achievement enables precise monitoring of NO2 in the atmosphere with low power consumption. The sensor not only saves time and cost but also offers excellent resolution. It is expected to contribute to research on improving atmospheric conditions by detecting annual average concentrations of NO2 and monitoring real-time changes.

Another characteristic of this technology is its ability to adjust the carbon content in the raw material during the material synthesis stage, thereby altering the electrochemical properties. This can be utilized to develop sensors capable of detecting gases other than NO2, such as residual gases produced during the semiconductor manufacturing processes. The excellent chemical reactivity of the material can also be exploited to enhance the performance of electrolysis catalysts for hydrogen production.

Dr. Jihun Mun, a senior researcher of the KRISS Semiconductor Integrated Metrology Team, said, “This technology, which overcomes the limitations of conventional gas sensors, will not only meet government regulations but also facilitate precise monitoring of domestic atmospheric conditions. We will continue follow-up research so that this technology can be applied to the development of various toxic gas sensors and catalysts, extending beyond the monitoring of NO2 in the atmosphere.”

The results of this study, supported by the fundamental project of KRISS and the Nanomaterial Technology Development Project of Ministry of Science and ICT, were published in the August issue of Small Structures (IF: 15.9), a prestigious academic journal in the field of materials science.

- New CRM enables accurate measurement of nutritional and harmful components in coffee beans -

- Expected to enhance quality control of coffee beans and contribute to related basic studies through international cooperation -

# Coffee is an indispensable beverage in the daily lives of Koreans. In Korea, the per capita coffee consumption of the adult population is 2.7 times higher than the global average, and coffee imports (raw and roasted beans) reached a record high of 200,000 tons, amounting to approximately 1.7 trillion won last year. For food items like coffee, which are closely tied to daily routines, stringent quality control is crucial because they are highly sensitive to the reliability. The key to rigorous food quality management lies in the development of reference materials that assist in accurate component analysis.

The Korea Research Institute of Standards and Science (KRISS, President Dr. Ho Seong Lee) has developed the world’s first CRM(Certified Reference Material) capable of accurate measurement of the nutritional and harmful elements in coffee beans.

▲ The KRISS research team

A CRM, which provides accurate measurement values certified by an authoritative body, serves as a standard providing a reference for verifying the accuracy of measurement results and analysis methods. The newly developed coffee bean CRM allows for the accurate measurement of five nutritional elements (calcium, magnesium, iron, zinc, copper) and three harmful elements (lead, mercury, cadmium) within coffee beans.

According to domestic regulations, the permissible limit for the total lead content in roasted coffee, instant coffee, and other coffee products is 2 mg/kg or less. In Europe, the cadmium content in dried edible coffee beans is regulated to be 0.05 mg/kg or less, and the lead content is restricted to 1 mg/kg or less. The lead, mercury, and cadmium content in this CRM are all approximately 0.1 mg/kg, which meets the standards for both domestic and European regulations.

▲ The Coffee bean CRM for elemental analysis

To develop this CRM, the Inorganic Metrology Group at KRISS freeze-dried a large quantity of raw coffee beans and obtained a homogeneous sample through multiple grinding and mixing processes. The sample was then sterilized through irradiation, producing a CRM with outstanding stability and homogeneity.

To provide certified measurement values with the world’s highest level of accuracy, this CRM employs isotope dilution mass spectrometry for measurement, one of the most reliable measurement methods in the field of chemistry. With this method, KRISS achieved an accuracy which is more than three times better than that of the conventional measurement methods used by food testing institutions.

▲ The KRISS research team is measuring elemental components using isotope dilution mass spectrometry.

While coffee is widely favored with a substantial volume of international trade, a CRM for elemental analysis of coffee beans, allowing their quality control, has been absent. The newly developed coffee bean CRM by KRISS, however, is expected not only to enhance the measurement reliability and evaluation system of domestic food testing institutions but also to contribute to various fundamental coffee-related research through international collaboration such as overseas distribution.

Dr. Kyoung Seok Lee, the director of Division of Chemical and Biological Metrology, said, “This achievement represents a technological advancement that can significantly improve the quality control level of coffee, a popular beverage as well as heavily imported product. KRISS will continue to develop CRMs for foods such as Korean cabbage, blueberry, and pork, so as to make healthy and safe dining table for the nation.

The coffee bean CRM, developed with support from the fundamental project of KRISS, is currently available on the KRISS Measurement Service website (eshop.kriss.re.kr).

- KRISS-ETRI-KAIST establishes the Convergence Research Center for Meta-Touch; 12 participating institutions for six years -

- Aiming to lead the metaverse market through haptic standardization and development of related devices/software -

The Korea Research Institute of Standards and Science (KRISS, President Dr. Ho Seong Lee) is partnering government-funded research institutes and universities to create a hyper-realistic metaverse that can be touched.

 ▲ The signboard of the Convergence Research Center for Meta-Touch is being unveiled

▲ Group photo at signboard hanging ceremony of the 

Convergence Research Center for Meta-Touch

On 13th December 2023, KRISS held a signboard hanging ceremony to announce the establishment of the Convergence Research Center for Meta-Touch at its headquarters in Daejeon. The event provided various programs such as progress reports about the Center, gatherings of researchers, a signboard hanging, and visits to research sites. It attracted over 50 key figures, including representatives from the Electronics and Telecommunications Research Institute (ETRI), the Korea Advanced Institute of Science and Technology (KAIST), and the National Research Council of Science and Technology (NST).

Supported by the NST, the Convergence Research Center for Meta-Touch will invest 39 billion KRW until 2029 in the development of haptic standards and haptic systems to create a hyper-realistic metaverse. The Center, led by KRISS, with KAIST and ETRI as the main organizers, will carry out five convergence research projects. Participating universities include Sungkyunkwan University, Korea National University of Transportation, Ajou University, Pohang University of Science and Technology, and Kyung Hee University.

Traditional metaverse environments, focusing on audiovisual technologies, have limitations in enhancing realism and immersion because they do not reflect the physical contact occurring in real life. As an alternative, haptic interfaces, which enable natural interactions in the virtual world, are currently gaining attention as an essential technology for the hyper-realistic metaverse.

The development of devices that can measure and display tactile sensations is still in its early stages compared to auditory devices. Due to the monopoly of fundamental technology for haptic interaction by certain countries, including the United States of America, and the absence of related standards, the game or metaverse creators are developing technologies confined to specific haptic devices. This results in lowering the device compatibility and restricting market entry.

The Convergence Research Center for Meta-Touch aims to address these issues by establishing haptic standards and developing high-performance haptic devices and software. This includes materials and devices of haptic sensor, actuators reproducing hyper-realistic tactile sensations, and rendering technology for hyper-realistic haptic experiences. Their ultimate goal is to organically integrate these technologies to create a combined haptic system that enhances immersion in metaverse and gaming environments.

The Center will operate as a sunset organization, dissolving after achieving its research objectives. Researchers from the 12 participating institutions will collaborate at the KRISS headquarters to maximize research efficiency, and they will return to their respective organizations when the project concludes.

Dr. Min Seok Kim, the head of the Convergence Research Center for Meta-Touch, said, “By securing fundamental technology for haptic interaction and leading related standard technologies, we will enhance the national competitiveness in the metaverse industry and contribute to the preoccupancy of the haptic market. We aim to achieve outstanding results by cooperating with various industries, universities, and research institutes.”

Commercialization of Next-Generation Secondary Batteries

The research team, led by Dr. Hosun Shin from the Interdisciplinary Materials Measurement Institute at the Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park), and Professor Jae Yong Song’s team from the Department of Semiconductor Engineering at Pohang University of Science and Technology (POSTECH, President Seong Keun Kim), developed a long-life organic electrode that has potential to expedite the commercialization of next-generation secondary batteries.

Electrodes in lithium-ion secondary batteries, commonly used in electric vehicles and other applications, are predominantly composed of inorganic materials such as nickel, cobalt, manganese, and aluminum. These mineral resources have limited reserves, and their supply can become unstable depending on the international geopolitical situation.

Organic-based electrodes are considered a key technology for next-generation secondary batteries, capable of addressing the aforementioned drawbacks. Organic materials can be synthesized in large quantities, offering excellent cost competitiveness compared to inorganic materials which require the mining of finite resources. Additionally, they have the advantage of being lightweight and flexible in relation to their capacity.

▲ Researchers from the KRISS Smart Devices Team are conducting experiments on the fabrication of long-life organic electrodes and charge/discharge performance.

However, organic electrodes easily dissolve in the electrolyte solution within the battery when ionized* during charging and discharging, leading to the rapid degradation of the battery’s lifespan. To address this issue, a solution involving the chemical optimization of the structure of organic molecules was proposed. Its complicated process and low yield, however, render it impractical as an alternative.

 * Ionization: A reaction in which a neutral molecule or atom acquires an electric charge through the movement of electrons

▲ Long-life organic electrode developed by the KRISS-POSTECH joint research team

The long-life organic electrode developed by the KRISS-POSTECH joint research team has significantly enhanced the lifespan of batteries using nano-composite materials. Its key advantage lies in production method; being produced by physical mixing makes it more practical for commercialization than previously proposed chemical approaches.

▲ Flexible pouch-type secondary battery with long-life organic electrodes (left)

/ LED illumination powered by the developed organic cell (right)

The key to this technology is the fabrication of the nanocomposite material. Among the candidate materials for the organic electrodes, the research team chose DMPZ, a material with high energy density, and PTCDA, a material with excellent electrochemical stability. The research team carried out an experiment with this composite made by cryo-milling, and the results showed that the mutual charge transfer of the two materials helped maintain electrically neutral state. Approximately 90% of the initial capacity was retained after 650 cycles of charge and discharge, and outstanding performance was observed even during high-speed charging and discharging. On the other hand, the DMPZ-only electrode exhibited a 20% decrease in lifespan within the first five charge and discharge cycles.

▲ The research team is mixing cryo-milled materials to create a long-life organic electrode material.

▲ The research team is testing the charge/discharge performance of the pouch-type battery made with long-life organic electrodes.

Furthermore, the research team has successfully developed a pouch-type battery using the long-life organic electrode, demonstrating the potential contribution of their work to the commercialization of flexible lithium secondary batteries.

In addition to its application to secondary batteries, this new achievement can contribute to various fields, for example, water electrolysis and gas sensors by enhancing the electrochemical stability and lifespan of organic-based electrodes.

Dr. Hosun Shin, the leader of the KRISS Smart Devices Team, stated, “For a successful transition to green energy, it is crucial to drive innovation in materials to surpass the limitations of existing secondary batteries. We anticipate that our work will expedite the commercialization of next-generation secondary batteries and encourage future research on organic electrodes across various fields.”

Supported by the Creative Materials Discovery Program of the National Research Foundation of Korea (NRF) under the Ministry of Science and ICT, the results of this study have been domestically and internationally patented. It was also published in the August issue of Energy Storage Materials (IF: 20.4), an international prestigious journal.

 - Impedance measurement standard has been developed in the sub-Terahertz frequency band for 6G, marking the first international comparison -

- Domestic device is expected to replace high-cost imported calibration device, laying the foundation for the growth of Korea’s 6G industry -

# The Korean government aims to commercialize 6G by 2028, with a total investment of 1 trillion KRW in the related research, leading to increased interest in the frequencies intended for 6G. However, the lack of electromagnetic wave measurement standards in the sub-Terahertz frequency range, a promising candidate for 6G, makes it challenging to verify technological reliability.

The Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) has developed an electromagnetic wave measurement standard for a candidate frequency band of 6G.

▲ KRISS Guided Wave Research Team of Electromagnetic Wave Metrology Group

The newly developed standard pertains to the electromagnetic impedance* of the D-band (110–170 GHz), which shows promise as a 6G candidate frequency band. This is one of the essential standards among electromagnetic wave measurement standards, serving as a criterion for peformance evaluation in fields where electromagnetic waves are utilized, such as communication and defense.

 * Impedance: A fundamental value in electromagnetic wave measurement that indicates the degree of resistance encountered as electromagnetic waves propagate.

The frequency range to be used for 6G has not been decided yet. However, the high-frequency range is considered suitable for the fast transmission of large-capacity data because the higher the frequency range, the broader the communication bandwidth in general. It is akin to how the 16-lane roads can handle more traffic than the two-lane roads. The D-band frequency, corresponding to the sub-Terahertz** range among high-frequency bands, has come under the spotlight as a candidate frequency for 6G. This is because it experiences minimal losses due to water vapor or oxygen and can transmit a large number of signals over a wide bandwidth, both distantly and uniformly.

 ** Sub-Terahertz: A frequency range of 100–300 GHz, drawing attention as a candidate frequency for 6G that enables 1 TB transmission per second.

▲ Electromagnetic impedance measurement system developed by KRISS researchers

The Electromagnetic Wave Metrology Group at KRISS has established an electromagentic wave impedance measurement standard for the D-band, becoming the third in the world after Japan and Germany. Moreover, the international equivalence has been secured through the comparison with Germany. This marks the first international comparison for impedance measurement standards above 110 GHz.

The primary frequency range for 5G communication is below 30 GHz, and the established electromagnetic wave measurement standards have been confined to frequencies below 110 GHz. Even if 6G-related components or parts usable above the D-band are developed, there has been a lack of standards for performance evaluation.

▲ Results of comparison of D-band impedance with PTB, Germany

The development of new standard, however, enables the verification of the performance of various 6G-related components and parts with high reliability. This standard is applicable not only to 6G but also to all fields where electromagnetic waves at D-band frequencies are utilized, including defense radar systems.

▲ Impedance calibration device developed by KRISS 

KRISS has developed its own D-band impedance calibration device to distribute the newly developed electromagnetic wave standard to the industrial sector. Previously, circuit analyzers used for impedance measurements had to be calibrated with expensive imported device. However, with this domestication, more precise measurement standards can now be provided to the industry at significantly reduced costs.

Dr. Jae-Yong Kwon, a head of the Electromagnetic Wave Metrology Group, said, “The development of the new standard and the domestication of calibration device will help Korea secure international credibility for domestic 6G technology. We will establish additional electromagnetic wave measurement standards for RF power, attenuation, antennas, and more, and continue follow-up research up to the 300 GHz frequency band, allowing stable adaptation to 6G.”

Such follow-up research has not yet been explored internationally, and the Electromagnetic Wave Metrology Group at KRISS has received collaboration proposals from leading countries such as Germany and the United States. KRISS expects to continue research for securing Korea's leadership in 6G technology by working closely with its industrial and academic partners, including LG Electronics and KAIST.

Supported by KRISS, the results of this study were published in the international journal IEEE Transactions on Instrumentation and Measurement (IF: 5.6) in July 2023.

The Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) has embarked on a mission to enhance the emergency preparedness and response capabilities of member countries of the Association of Southeast Asian Nations (ASEAN) for nuclear and radiological accidents.

▲ KRISS Radioactivity Metrology Team

In late May, KRISS successfully completed the development of educational materials designed to prepare and respond to emergencies, such as the Fukushima Nuclear Accident, for the benefit of 10 ASEAN member countries. Consisting of three instructional videos and two handbooks on radioactivity measurement, the materials are aimed at facilitating rapid responses to nuclear or radiological emergencies.

▲ Handbooks on Radioactivity Measurement

To effectively manage nuclear and radiological accidents, there is an urgent need for trained personnel and infrastructure capable of producing and analyzing environmental radioactivity measurement data not only swiftly but also accurately. ASEAN countries, including the Philippines and Vietnam, are expanding the use of nuclear energy by planning to build nuclear power plants. Although the countries possess different levels of technology development and related infrastructure, they share common development needs and issues. Capacity building of experts can fill the gap in advancement and contribute to solving their common problems.

These educational materials were developed in response to a request for cooperation from the RCA* Regional Office (RCARO), established under the auspices of International Atomic Energy Agency (IAEA).

 * RCA: Regional Cooperative Agreement for Research, Development and Training Related to Nuclear Science and Technology for Asia and the Pacific

▲ Instructional Video of Analysis Procedure

As one of the partner countries collaborating with the ASEAN Network of Regulatory Bodies on Atomic Energy (ASEANTOM), Korea has been actively involved in various joint initiatives aimed at enhancing nuclear safety in the ASEAN region.

Since the 2010s, the Global Metrology Academy (GMA) of KRISS has been providing education on precise measurement of radiation to standards organizations in developing countries including those in ASEAN. Given its experience in creating instructional videos for training emergency responders, KRISS was chosen as a partner in the RCA's project to strengthen radioactivity emergency preparedness and response capabilities in ASEAN.

The educational materials recently distributed to the 10 ASEAN countries were developed based on KRISS’s expertise in radiation measurement education and further refined with input from domestic experts in environmental radiation analysis. These materials comprehensively cover procedures for environmental sampling, pre-processing, analysis, and data generation in the event of a radiological accident. Handbooks are structured to guide workers through the necessary steps, and key contents are presented in video format to enhance practical usability.

Dr. Byoung-Chul Kim, a senior researcher from Radioactivity Metrology Team of KRISS, stated, "Korea realized the importance of readily deployable experts in environmental radioactivity during emergencies following the Fukushima Nuclear Accident in 2012. Through the development of these educational materials, our goal is to transfer Korea’s outstanding radiation measurement capabilities to ASEAN countries."

In August, KRISS invited the related organizations to Korea and hosted training sessions for them, as part of its ongoing efforts to foster expertise in environmental radiation measurement within the ASEAN region.

- New CRM capable of analyzing low levels of acrylamide in infant formula -

- Boosting reliability of measurement and alleviating public concerns by meeting recommended standards for infant food -

The Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) has developed a Certified Reference Material (CRM)* for the accurate analysis of low levels of acrylamide in infant formula.

 * CRM: A reference material that serves as a standard in determining the accuracy of measurements and analytical methods

Acrylamide is recognized as a probable carcinogen by the International Agency for Research on Cancer (IARC), an agency affiliated with the World Health Organization (WHO). It forms during the high-temperature cooking of carbohydrate-rich foods and is commonly found in items such as French fries, snacks, and coffee. Notably, acrylamide is also present in infant formula, making accurate quantifiaction and management imperative.

In Europe, regulations targeting the reduction of acrylamide in food were initiated in 2017, and further strengthening of these regulations is anticipated this year. In South Korea, the Ministry of Food and Drug Safety established recommended standards for acrylamide levels in various foods in 2021 and has been overseeing compliance.

▲ Infant formula CRM developed by KRISS for acrylamide analysis

KRISS has achieved a significant breakthrough with the development of the CRM designed for the analysis of low-concentration acrylamide. It enables the precise examination of low-concentration acrylamide in food matrix, marking a pioneeirng achievement as the world’s first CRM to improve the calibration and quality control of the analytical procedure.

KRISS has been at the forefront of the research related to international comparison of the acrylamide measurement since 2007, with a notable milestone being the development of a CRM for acrylamide analysis in potato chips in 2008.

▲ KRISS researchers are measuring acrylamide content in the infant formula CRM using mass spectrometry.

The concentration of acrylamide in the new CRM is merely one-tenth of that found in the previously developed potato chip CRM, which allows for the precise measurement of trace amounts of acrylamide in food. Moreover, the new CRM was developed in accordance with the regulations by the European Commission (EC) for foods intended for infants and young children.

The infant formula CRM can be used to verify the analytical method for the acrylamide analysis at low levels of concentration. It is expected to enhance the measurement reliability of analytical laboratories and contribute to the refinement of evaluation systems.

Dr. Sunyoung Lee, a principal researcher at KRISS, said, “Given the high sensitivity to safety associated with infant foods, acrylamide benchmark levels are even stricter than those applied to other food categories. Consequently, thorough preventive management and heightened reliability of analysis are necessary. The distribution of this CRM aligns with the demand for establishing measurement standards in the food industry and will help alleviate public concerns regarding food safety.”

The outcomes of this research, supported by the fundamental project of KRISS, were published in Analytical and Bioanalytical Chemistry (IF: 4.478), an international academic journal, in June 2023.

Supported by the fundamental project of KRISS, the outcomes of this research were published in Analytical and Bioanalytical Chemistry (IF: 4.478), an international academic journal, in June 2023.

- Defects on the metal separator of fuel cells are three-dimensionally measured for real-time inspection during the production process -

- Measurement is carried out by pattern projection based on deep learning to inspect surfaces with low reflectivity or various patterns -

# Fuel cells, integral components of hydrogen fuel cell electric vehicles(FCEVs), serve as eco-friendly energy conversion systems that generate electric power and heat through the chemical reaction of hydrogen and oxygen. Korean local governments are enthusiastic about investing in relevant equipment to expand the FCEV market, but they often face opposition from local residents. To alleviate citizens’ concerns, it is necessary to establish infrastructure that can ensure both the productivity and safety of hydrogen fuel cells.

The Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) has developed a technology for real-time detection of micro defects on the fuel cell surface during the production process.

▲ KRISS Reserach Team

The newly developed technology is based on deep learning and enables real-time 3D measurement. It can detect defects on the surface shape in a single shot, allowing continuous monitoring of product quality without interrupting the manufacturing process.

A single-shot pattern projection method is employed for the real-time 3D measurement of the surface shape. The light with dense composite grid pattern is projected onto the surface of an object, and then the deformed pattern upon reflection is analyzed to obtain 3D information about defects or damages.

However, one limitation of this methodology is that it cannot measure surfaces with low reflectivity or various mixed patterns. For instance, the metal separator, which is a core component of fuel cells, is challenging to be inspected using real-time 3D measurement because it is made of stainless steel (SUS) with an uneven surface.

▲ DYnet++, the newly developed deep learning network by KRISS

▲ The 3D shapes predicted by the trained DYnet++ network

To apply this technology to fuel cell samples, the research team further trained the AI algorithm using data on metal separators with surface defects. The 3D morphology measurement results shows that dents and scratches on the sample surfaces, which are difficult to be determined through conventional 2D inspection, are successfully detected in a single shot because the AI algorithm acquired the application capabilities even with a small amount of data.

▲ Measurement results of a fuel cell sample with a rough surface and low reflectivity

Thousands of image data with arbitrary complex patterns and their corresponding 3D shapes are acquired and used to train the designed DYnet++ network. Transfer learning* is employed for the analysis of data obtained under the new environmental conditions, which requires only one-tenth of the amount of data to modify the trained model compared to what was used to build the initial algorithm. Based on the modified model, the 3D measurement results for various complex patterns can be predicted.

*Transfer learning: A machine learning technique that involves applying a pre-trained model to a new problem, particularly useful when there is limited data or time for training.

The technology developed through this research can be easily applied to the production line, regardless of the shape or size of the subject to be measured. It enables automatic inspection of defects even during a manufacturing process with external vibrations and significant temperature changes. This technology can contribute to the introduction of smart factories in various areas of the manufacturing industry, including fuel cells, by increasing productivity, improving product quality, and reducing costs.

Dr. Young-Sik Ghim, the leader of the Optical Imaging and Metrology Team, stated, “This technology can be used for real-time inspection of various faults and defects in fuel cell metal separators. It can not only maximize performance but also improve the durability and safety of the fuel cells that are currently being produced.”

KRISS will continue to conduct further studies to apply this technology to various industrial sites.

Supported by the Technology Innovation Program of the Ministry of Trade, Industry & Energy, the results of this research were published online in IEEE Transactions on Industrial Electronics (IF: 8.162), an internationally renowned journal in the field of electromagnetics, in March 2023.

- KRISS-NCAM joint research team proposes method of correcting methane emissions from rice paddy soil -

- Results validate emissions of greenhouse gases and enhance reliability of greenhouse monitoring for agriculture, forestry and livestock industries -

The joint research team of Dr. Namgoo Kang from the Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) and Dr. Minseok Kang from the National Center for Agro Meteorology (NCAM, Chairperson Jong-ho Park) developed a novel technology that enhances the reliability of measurement of methane emissions from rice paddy fields.

△ Dr. Namgoo Kang, a team leader of the Measurement Instrumentation and Data Verification Research Team, is developing technology to correct the measurement of methane emissions from the rice paddy soil.

Methane is a greenhouse gas with 25 times the greenhouse effect per unit material compared to carbon dioxide. Since methane accounts for about 30% of greenhouse gas emissions in the domestic agriculture sector, accurate measurement of methane emissions from rice paddy soil is essential to establish effective policies in response to climate change.

The world’s most widely used method for measuring methane emissions from rice paddy soil is a chamber method. This method involves installing box-shaped chambers at regular intervals on the soil and calculating the amount of methane collected per unit area and time. However, emission levels may be distorted as continuous monitoring is not possible, and the results are limited to the confined areas within chambers.

The eddy covariance method*, which addresses the limitations of the chamber method, allows continuous measurement of methane emissions from rice paddy soil in open and wide spaces. The problem is that although the measurement results may be affected by the height of installed measurement equipment depending on soil conditions, the related research and guidelines are not enough. That’s why the chamber method is still being used to calculate country-specific emission factors for registration in the database of the United Nations Framework Convention on Climate Change (UNFCCC).

* Eddy covariance method: A method for measuring and calculating vertical turbulent fluxes of trace gases (carbon dioxide, methane, etc.) in the atmosphere at high speed (10 times per second)

△ Methane flux observation system based on the eddy covariance method installed at the rice paddy field in Cheorwon, Gangwon-do Province

Using eddy covariance data collected from rice paddy soil in Cheorwon, Gangwon-do Province in 2020 and 2021, the KRISS-NCAM joint research team identified the difference in measurement results due to changes in observation height for the first time and proposed a method for correction.

The basis of this achievement is the technology of using methane reference gas developed by KRISS for precise calibration of both the chamber method and the eddy covariance method. This is the first research to which the internationally recognized standard was applied for measuring methane emissions from the rice paddy soil.

△ The rice paddy field with the methane flux observation system installed based on both the chamber method and the eddy covariance method

The results can be applied to verify the data on national greenhouse gas emissions and enhance data reliability through a mutual comparison of the chamber method and the eddy covariance method. In addition, it can contribute to improving measurement accuracy and integrating data in various greenhouse gas observation networks around the world.

Dr. Namgoo Kang, a team leader of the Measurement Instrumentation and Data Verification Research Team and a professor of Precision Measurement Major in the University of Science and Technology, said, “The eddy covariance method is a core strategic technology that will establish itself as a global standard technology supplementing the chamber method. Our results will contribute to the establishment and the implementation of plans to achieve carbon neutrality across agriculture, forestry, and livestock industries at the national level by 2050.”

△ Dr. Namgoo Kang is inspecting the correction system for methane emissions from the rice paddy soil.

The joint research team plans to continue their research, focusing on the potential of the eddy covariance method in forestry, horticultural and livestock industries. Specifically, they will develop a customized quality management technology for smart agriculture in order to enable accurate monitoring of greenhouse gases.

Supported by KRISS as well as the Rural Development Administration’s Low-Carbon Green Rice Production Technology Development Program and New Agriculture and Climate Response Program, the study was published in Agricultural and Forest Meteorology (IF 6.424), a leading international journal in the field of agrometeorology, on March 15.

- KRISS demonstrated carrier transport mechanism of photoanode with protective film to optimize green hydrogen production -

The development can contribute to the realization of carbon-free green hydrogen and artificial photosynthesis -

Hydrogen has been gaining attention as a clean and efficient energy source. However, is hydrogen really environmentally friendly? Most hydrogen commonly used now is “grey hydrogen” derived from fossil fuels. Since its production process accompanies generation of green house gas, it can be said that grey hydrogen is not environmentally friendly in the strict sense. The era of “green hydrogen” without carbon emissions has not yet begun.

The Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) has demonstrated the key to the longevous and efficient photoanode with protective film, which is used to produce hydrogen via water splitting using solar energy. This is expected to bring forward the era of environment-friendly “green hydrogen.”

Green hydrogen is produced without carbon emissions by using renewable energy sources. A representative method to produce green hydrogen is photoelectrochemical water splitting using photoanode which is directly immersed in electrolyte and can absorb sunlight. As a result, the photoanode directly splits contacting water into hydrogen and oxygen using absorbed solar energy. However, as the photoanode is in direct contact with electrolyte, it is prone to surface corrosion. Surface protective coatings were deposited on the surface to prevent surface corrosion.

Typically, oxide materials such as titanium dioxide (TiO2) are used as protective films for photoanodes. Although oxide materials are poor conductors of electricity, their conductivity can be modulated when oxygen defects, serving as a channel for charge transport, are formed. The key to extending the lifespan of photoanodes is to develop a protective film durable enough to prevent electrode corrosion and capable of maintaining optimal electrical conductivity.

▲  Highlighting a study on a mechanism of photoelectrochemical water splitting on Si photoanode passivated with TiOx layer with various defect density from the laboratories of Dr. Ansoon Kim at KRISS (Published on the back cover of Journal of Materials Chemistry A)

KRISS has developed the world’s first technology for systematically modulating the levels of oxygen defects in a titanium dioxide (TiO2) protective film of photoanode to maximize hydrogen production efficiency. In order to explore the role of oxygen defects in the charge transfer mechanism, the research team determined the optimal levels of defects that maximize photoanode lifespan and hydrogen production by using X-ray photoelectron spectroscopy and electrochemical analysis.

 ▲  For the efficient PEC water splitting, it is crucial to balance two factors by systematically controlling the defect density in TiOx passivation layer of n-Si photoanode, which are (1) accessible density of state for carrier transportation in forbidden gap and (2) favorable interface energetics.

Unlike past studies that relied on spontaneously formed oxygen defects in the protective film during manufacturing process, this research proposes a direct method of production that controls the levels of oxygen defects, enabling mass production. According to the experimental results, the photoanode without a protective film showed a rapid degradation in lifespan within an hour, causing the hydrogen production efficiency to fall below 20 % compared to the initial state. On the other hand, the photoanode with optimized protective film maintained a hydrogen production efficiency of over 85 % even after 100 hours.

This achievement has the potential to enhance the efficiency and lifespan of photoanodes and can be applied to other clean technologies that rely on photoanodes. The artificial photosynthesis technology that captures carbon dioxide and converts it to a chemical energy source using solar energy is one of the examples.

Dr. Ansoon Kim, a principal researcher at KRISS Interdisciplinary Materials Measurement Institute, said, “This approach can improve photoanode lifespan by approximately 10 times and significantly contribute to the commercialization of green hydrogen.”

KRISS plans to conduct further research to unveil the optimal levels of oxygen defects and underlying principles that maximize the lifespan of photoanodes.

Supported by mainly KRISS and partly the Technology Innovation Program of NRF (National Research Foundation of Korea), the study was published on the back cover of Journal of Materials Chemistry A (IF=14.511), an international journal in the field of materials chemistry, on 28th February 2023.

- KRISS paves the way for spintronics technology revolution by implementing the world’s first skyrmion transistors -

- Skyrmion flow control is expected to accelerate development of next-generation ultra-low-power devices -

In an era marked by an escalating energy crisis, the world stands on the precipice of a transformative revolution in spintronics technology, promising ultra-low power consumption paired with superior performance. To illustrate the potential, consider this: the power consumed by AlphaGo during its famous Go game in 2016 equaled the daily power use of 100 households. By 2021, Tesla's autonomous driving AI required over ten times that amount of power for learning.

In response to this growing demand, the Korea Research Institute of Standards and Science (KRISS, President Hyun-min Park) has pioneered the world's first transistor capable of controlling skyrmions. This breakthrough paves the way for the development of next-generation ultra-low-power devices and is anticipated to make significant contributions to quantum and AI research.

  ▲ KRISS Quantum Spin Team

Skyrmions, arranged in a vortex-like spin structure, are unique because they can be miniaturized to several nanometers, making them movable with exceptionally low power. This characteristic positions them as a crucial element in the evolution of spintronics applications.

The explosive growth of electronic engineering in the 21st century can be traced back to the 1947 invention of the transistor at Bell Laboratories in the United States. Acting as an amplifier and switch for electrical currents, the transistor has been pivotal in the field of electronic engineering. The discovery of the skyrmion in 2009 sparked widespread research into a skyrmion-based transistor, but the absence of essential technology to control skyrmion movement thwarted these efforts.

This bottleneck has been overcome with KRISS's newly developed skyrmion transistor, which leverages proprietary technology to electronically manage the movement of skyrmions created in magnetic materials. This innovative solution enables the precise control of skyrmion flow or halting, akin to how conventional transistors modulate electric current.

A critical aspect of managing magnetic skyrmion movement lies in controlling magnetic anisotropy, which influences the energy of skyrmions. Previous research endeavored to regulate magnetic anisotropy through oxygen movement within devices but failed to achieve uniform control. Overcoming this challenge, the KRISS Quantum Spin Team developed a groundbreaking method for uniform control of magnetic anisotropy by leveraging hydrogen within aluminum oxide insulators, marking a world-first in the experimental implementation of skyrmion transistors.

 ▲ Operation of a skyrmion transistor

This milestone represents yet another foundational technology for spintronic devices, following the institute's 2021 achievement in the generation, deletion, and movement of skyrmions. The advent of the spintronics transistor is set to expedite the development of spintronics-based devices, such as neuromorphic and logic devices, which offer substantial advantages in power consumption, stability, and speed over traditional electronic devices.

Dr. Chan Yong Hwang, a director of the KRISS Quantum Technology Institute, expressed, "Major Korean companies are pivoting their focus to next-generation semiconductors that utilize spintronics to transcend the constraints of current silicon semiconductors. We plan to advance spintronics-related technology further and incorporate them into next-generation semiconductor devices and quantum technology."

Reflecting on the significance of the achievement, Dr. Seungmo Yang, a senior researcher at KRISS, stated, "The transistor ignited the digital revolution of the 20th century. Now, the skyrmion transistor is poised to catalyze a similar transformation, propelling the spintronics technology revolution of the 21st century."

This study was supported by various programs of the National Research Foundation of Korea(NRF) and was jointly conducted by the Quantum Spin Team of the Quantum Technology Institute, Prof. Bae Ho Park’s team at Konkuk University, Prof. Sungkyun Park’s team at Pusan National University, and Dr. Hee-sung Han of UNIST. The results were published as a frontispiece in the world-renowned journal Advanced Materials (IF: 32.086) in December last year.

- Improved performance with less time and cost to accelerate advances in domestic quantum research -

- Higher scalability and integration capacity than single-photon sources; mass production supported by existing infrastructure -

The Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) and Korea Advanced Institute of Science and Technology (KAIST, President Kwang-Hyung Lee) developed a new type of single-electron source that can be utilized in quantum information technology. The source, which offers better performance compared to existing sources while saving time and cost, is expected to accelerate advances in quantum computing and quantum information technology in Korea.

▲ KRISS-KAIST Joint Research Team

(From the left) KRISS Principal Research Scientist MinKy Seo, KAIST Ph.D. student WanKi Park, KRISS Principal Research Scientist Bum-Kyu Kim, Myung-Ho Bae, and Nam Kim.

A single-electron source is a device that emits electrons one by one based on semiconductor technologies. This ability to control individual particles is essential to realize quantum states for quantum information technology and quantum computing.

Quantum technology research based on moving particles has mostly relied on single photons, not single electrons while single-electron sources have been developed to realize the definition of ampere. This is because the electron’s energy generated from single-electron sources is too high to observe quantum phenomena, or too low  to separate electrons from holes* have been difficult.

*Hole: the lack of an electron at a position where one could exist in an atom or atomic lattice.A hole behaves like an electron with a positive charge.

▲ Single-electron source and an output current map

▲ Development process of single-electron sources using two-dimensional semiconductors

The single-electron source is basically operated with a quantum well (or quantum dot) defined by applying local electric fields in a two-dimensional compound semiconductor. The quantum well synchronized with an external signal periodically absorbs and emits certain number of electrons from an electron reservoir. Finally, only one electron flows into the desired channel using an energy filter under a high magnetic field. It combines the advantages of existing single-electron sources, and thus can be applied to quantum computing and quantum information technologies without complex techniques or expensive equipment.

Quantum technologies with single-electron sources based on two-dimensional semiconductors allow us to manipulate quantum states, compared to the quantum optics with single-photon sources. Thanks to the high scalability and integration capacity, it is possible to fabricate multiple electron sources on a single wafer and pack dozens of qubits* in small areas. Another advantage is that the industrial infrastructure for mass production is already available.

* Qubit: a basic unit of quantum information.

▲ Myung-Ho Bae, a principal research scientist at KRISS, and WanKi Park, a Ph.D. student at KAIST, are measuring the electrical characteristics of devices with the single-electron  measurement system.

Myung-Ho Bae, who leads the Single Electron Quantum Devices Team at KRISS, said, “Our results will significantly save time and cost for future research on quantum computing and quantum information technology. If applied to quantum computing, single-electron sources can achieve faster operation speed than superconducting or spin-based quantum computing.”

The team plans to establish a qubit system using the single-electron source to further boost quantum information technology.

Funded by the Ministry of Science and ICT’s Science Research Center Program and KRISS, the study was published in the leading journal Nano Letters (IF: 12.262) in November.

- Recognized for establishing national measurement standards in fluid flow and contributions to international activities in the Asia-Pacific region -

Seok Hwan Lee, a senior research scientist of the Flow Rate Measurement Team at Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park), received the APMP Young Metrologist Prize at the 38th Asia Pacific Metrology Programme (APMP) held in Tokyo, Japan on December 2.

▲ Seok Hwan Lee, a senior research scientist of the Flow Rate Measurement Team at KRISS

Lee has not only established national measurement standards in fluid flow, but also contributed to international activities in the Asia-Pacific region. In particular, he developed a system for micro flow rate and viscosity measurements, and enhanced the reliability of measurement standards through international comparisons. He recently published a paper on non-contact flow sensors for medical and semiconductor processes, and has actively fostered talent in measurement standards under various collaboration programs.

APMP is an international non-governmental organization established in 1977 for the development of metrological capability in the Asia-Pacific region. Every year, experts in related fields gather to discuss regional issues and measures for research cooperation.

Launched in 2006, the APMP Young Metrologist Prize is awarded to young scientists aged 40 or below who have outstanding research achievements in metrology and contributed to the development of APMP. 

- The first experimental realization of probing the high-energy spin-dependent electronic structures of two-dimensional quantum magnetic materials -

- Lay the foundation for commercializing low-dimensional quantum devices with next-generation quantum materials -

# Since the discovery of “dream-material” graphene in 2004, extensive research efforts have been focused on searching and characterizing new two-dimensional (2D) van der Waals (vdW) materials, including spin-polarized 2D magnetic materials that have been widely explored over the past few years.

A local research team* has successfully measured the spin-dependent electronic structures of 2D magnetic materials, which were previously limited in theoretical expectations.

* KRISS, Sejong University, Pohang University of Science and Technology (POSTECH), Seoul National University, Institute for Basic Science (IBS), Korea Basic Science Institute

▲ KRISS Low-Dimensional Materials Team

(Clockwise direction from left in back row) Suyong Jung, principal researcher; Duk Hyun Lee, post-doc researcher; Dong Han Ha, principal researcher; In-Ho Lee, principal researcher; Keun-Hong Min, student researcher

Two-dimensional magnetic materials are considered essential for realizing next-generation quantum information and memory devices. To exploit them in future device applications, it is imperative to assess the spin-dependent properties of the 2D magnets accurately.

Until now, measurements of the spin-dependent structures were possible only for a limited energy range, with most material characterizations relying on theoretical estimates instead. In addition, spin information is susceptible to the physical and chemical environment, so even a slight disturbance can result in a loss of spin information.

This study is the world’s first experimental realization of directly probing the high-energy spin-dependent electronic structures of 2D vdW magnetic material Fe₃GeTe₂ (FGT).

▲ Optical microscopic image of FGT device with defect-free vdW interfaces

The team applied a spin-dependent electron tunneling spectroscopy method to measure the high-energy spin-dependent electronic structure of FGT, and validated the experimental data with theoretical estimates. FGT is a well-known metallic ferromagnet that maintains its magnetic properties down to the single atomic layer and is considered an essential material in developing next-generation quantum spin and information device applications.

˚ Electron tunneling spectroscopy is an experimental technique that measures the electronic structures of condensed matter systems. Since the tunnel junction is susceptible to physical and chemical disturbances, spin-dependent electron tunneling spectroscopy is limited to a narrow energy range. Using atomically clean van der Waals* assemblies, however, the research team has extended the energy range without any loss of spin information and measured the high-energy spin-dependent electronic structures of FGTs.

* Physical forces causing push or pull between atoms and molecules.

▲ FGT-based magnetic tunnel junction device with defect-free van der Waals interfaces

Accurately assessing spin-dependent material properties of 2D magnetic materials with proper materials metrology approaches is crucial to develop next-generation quantum phase and information devices. In addition, 2D heterostructures with defect-free vdW couplings can provide an ideal device platform for realizing next-generation spintronic devices such as quantum memory and probabilistic memory.

Suyong Jung, principal researcher of the KRISS Low-Dimensional Material Team said, “Our research achievements are in line with the extensive research efforts on quantum magnetic materials in Korea. Furthermore, thanks to the strong collaborations with other research teams in Korea, we can expand the scope of quantum materials research and present the possibilities for commercializing low-dimensional spintronic devices with the 2D quantum magnets.”

The study was funded by KRISS, the Basic Science Research Program under the National Research Foundation of Korea, IBS Center for Artificial Low Dimensional Electronic Systems, and IBS Center for Correlated Electron Systems, and was published in the top-tier research journal in materials science, Nature Materials (IF: 47.656) on August 5.

- Accurately measures discharge amount of epoxy resin used in cellphone assembly -

- Improves yield and safety by keeping the process active and preventing clogged nozzles -

Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) developed a non-contact flow sensor capable of measuring the amount of epoxy used in the semiconductor fabrication process in real time. Through accurate monitoring of the discharge amount during the dispensing process, the sensor can enhance semiconductor yield.

▲ (From the left) Sung-hyuk Im and Seok Hwan Lee, Senior Researcher Scientist and Woong Kang, Principal Research Scientist at the KRISS flow measurement team

The dispenser used in the fabrication of electronic products plays the role of discharging epoxy. Epoxy is used as an adhesive in cellphone assembly due to its high viscosity and hardening property, or as an underfill resin to protect chips from stress. Devices are growing smaller thanks to the advances in semiconductor technology, and the accurate dispensing of resins in smaller volumes has become increasingly important. 

 ▲ Infrared Absorption-Based Non-contact Flow Sensor Developed by KRISS

Before introducing dispensers into the electronic packaging process, the discharge amount is checked using a balance. This prevents issues such as epoxy hardening, inaccurate discharge amount, and blockage of nozzles. Non-contact flowmeters are required for real-time monitoring of discharge amount without stopping the process, but small traces can be difficult to measure with existing ultrasonic flowmeters.

The sensor developed by the KRISS Flow Rate Measurement Team is based on the infrared absorption method, which allows real-time measurement of flow rate without cutting tubes or stopping the fabrication process. A local spot of the epoxy supply tube is heated using infrared, and an infrared absorption-based temperature sensor measures the flow from outside the tube.

▲ Non-contact Flow Sensor connected to epoxy dispenser

By comparing real-time measurements of discharge amounts to weights obtained using a balance, the team showed that the new sensor is capable of measuring small traces up to an accuracy of 1 µg (microgram; one millionth of a gram) for shots dispensed at 300 Hz. The sensor can be used to measure discharge amounts in the range of 10 µg to tens of mg in the actual semiconductor fabrication process.

The team is the first to develop a sensor capable of measuring discharge amounts of a dispenser during the semiconductor fabrication process in a non-contact manner and in real time. The advantages include higher yield from improved accuracy and non-interference of processes by clamp-on mounting.

▲ Experimental setup (left) for measuring dispenser discharge volume and enlarged image of sensor unit (right)

Currently, the team is conducting follow-up research aimed at commercialization. Korea has relied on foreign-made ultrasonic flowmeters for non-contact measurements of flow rate. If commercialization is successful, the Korean market will see the launch of non-contact flow sensors using domestic technology alone.

Seok Hwan Lee, Senior Research Scientist of the Flow Rate Measurement Team at KRISS, said, “Our technology can be applied to measure the flow rate of sulfuric acid and other liquid chemicals used in cleaning and etching in a non-contact manner. We hope to improve semiconductor yield while enhancing safety and efficiency.”

This study, funded by the joint research support program between the Ministry of Science and ICT and the European Union, was published online in the international journal Optics and Lasers in Engineering (IF: 5.67) in October.

- Expected to improve accuracy of toxicity assessment in the fields of medicine, chemistry, and food –

# Silica nanoparticles, which help in pore care by adjusting sebum secretion, are widely used in cosmetic products. The reactions of human body cells should be examined to assess the safety of nanomaterials.

The Korea Research Institute of Standards and Science (KRISS, President Hyun Min Park) revealed the limitations of cell culture systems used in assessing the toxic effects of nanomaterials on the human body.

▲ KRISS researchers (from the left of the back row to the clockwise direction, Principal Research Scientist Min Beom Heo, Vice President Tae Geol Lee, student researcher Jae Won Choi and post-doc researcher In Young Kim)

Nanomaterials have vast applications in medicine, chemistry, and food. Specifically, silica nanoparticles (silicon dioxide, SiO2) are widely used in cosmetics, food additives, and drug delivery systems. Since nanomaterials can cause various diseases when accumulated in the human body, toxicity assessments must be carried out to ensure they are used in safe amounts.  

While toxicity assessments can be performed through animal experiments, growing concerns over the ethical use of animals have led to cell culture systems becoming more widespread. In a cell culture system, cells originating from humans are cultured in an environment similar to the human body, and nanomaterials are processed to determine toxicity effects.

▲ Min Beom Heo, Principal Research Scientist at KRISS, is exposing nanomaterials to cells.

Two-dimensional cell culture systems have been the norm, but three-dimensional systems are being rapidly adopted as they offer an environment more similar to the human body. Three-dimensional systems are composed of human body cells, an extracellular matrix that surrounds and supports such cells, and essential nutrients for growth. A good example is organoids, which are derived from stem cells and mimic the structure and function of human organs.

The Nano-safety Team of the KRISS Safety Measurement Institute showed that the extracellular matrix used in a three-dimensional culture interferes with the penetration of nanomaterials, making it difficult to accurately assess toxicity.

▲ Results of nanomaterial toxicity assessment using 3 types of extracellular matrix

▲ Results of Permeability Analysis of Fluorescent Silica Nanomaterials

The research team established a three-dimensional cell culture system using three extracellular matrices, namely, Matrigel, alginate, and collagen type I, and exposed the system to silicon dioxide. Microscopic observations revealed that the silicon dioxide adhered to the scaffolds without reaching the cells. In addition, the results of toxicity assessments were different depending on the scaffold type.

The team’s study is the first to reveal the limitations of nanomaterial toxicity assessment using a three-dimensional cell culture system. With ISO’s recent development of a standard safety assessment method for nanomaterials using three-dimensional cell culture systems, the results are expected to have useful applications in the future.

 ▲ KRISS researchers are confirming the results of adsorption analysis of nanomaterials and extracellular matrix.

Principal Research Scientist Min Beom Heo said, “Our findings will serve as a useful reference in nanomaterial toxicity assessment using three-dimensional cell culture systems. We will conduct further research to develop more accurate and reliable methods of toxicity assessment.”

Funded by the Ministry of ICT and KRISS, the study was published in Sensors and Actuators B: Chemical (IF: 9.221), a leading journal in the field of chemical sensors, in October.

- Successful demonstration of energy analyzer using novel technology permits performance evaluation of electron microscopes -

- Electron microscope performance evaluation service to be provided to support local equipment industry -

Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) has succeeded in developing a high-performance energy analyzer, which is a key technology for determining the performance of electron microscopes. The service will be made available to local equipment companies, to foster the advanced microscope industry.

▲ KRISS Scientific Instruments Performance Evaluation Team

(From left) Junhyeok Hwang, doctoral student of UST-KRISS School; Takashi Ogawa, principal researcher; In-Yong Park, team leader; Ha Rim Lee, post-doc researcher

The performance of electron microscopes depends on the characteristics of the electron sources that produce the electron beams. This is because electron beams are focused on a lens to observe specimens. To allow precise focusing the energy distribution of the electron particles must be uniform, even when observing extremely small specimens. As such, it is important to accurately measure the energy width, an indicator of the uniformity of energy distribution, in order to develop high-performance electron microscopes.

▲ In-Yong Park, team leader of the Scientific Instruments Performance Evaluation Team prepares to measure the energy width of an electron beam.

Many local companies have successfully developed electron microscopes, but have had to rely on numbers available in the literature instead of actual measurements, because there has been no energy analyzer capable of measuring energy width. The conventional approach does not allow comprehensive performance validation, as slight differences in performance across individual microscopes are overlooked. For companies to enter the high-performance electron microscope market, they must be able to obtain accurate measurements of energy width.

The KRISS research team developed design technology from simulations performed in 2019, and successfully developed a pre-lens retarding field energy analyzer. The production cost was relatively cheap at around a few million won, and the device can measure an energy distribution broadening of 13.8 meV. This energy analyzer can be utilized to perform evaluations of advanced research equipment, including scanning electron microscopes. It is only 60 mm in size, making it useful as an independent analyzer, or it can be attached inside existing equipment, for microscopes with an integrated electron beam performance evaluation function.

▲ Principle of the pre-lens retarding field energy analyzer

Energy analyzers can be mainly divided into two types. The hemispherical electron energy analyzer offers outstanding energy resolution, but is expensive and much larger in size (700 mm). The grid-type retarding field energy analyzer is compact and affordable, but is inadequate for performance evaluation as its energy resolution exceeds 300 meV.

In addition to using the existing measurement test of angular current density, KRISS established an energy width measurement platform, and launched a testing service for local companies in August. By the end of this year KRISS plans to establish an energy resolution performance evaluation platform to assess the influence of magnetic field, noise and vibration.

In-Yong Park, team leader of the KRISS Scientific Instruments Performance Evaluation Team, said, “Previously, Korea lacked technological self-reliance for high-performance electron microscopes despite their importance in materials, parts, and biotechnology. The new platform for comprehensive performance evaluation, ranging from individual microscope parts to the entire system, will pave the way for local companies to enter the high-performance microscope market.”

The results of the study, funded by KRISS and the Basic Science Research Program under the National Research Foundation of Korea, were published in Microscopy and Microanalysis (IF: 4.099) in September.

- KRISS develops high-precision measurement technology for thermal properties of materials that withstand temperatures over 3,000 K -

- Expected to enhance new materials development and safety and efficiency of major industries exposed to extreme conditions, such as aerospace, aviation, national defense, and energy -

Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) developed high-precision technology to measure the thermal properties of molten refractory metals in ultra-high temperature environments over 3,000 K*, by using electrostatic levitator.

* K (Kelvin): Unit of temperature. 3,000 K is equivalent to 2,727 °C. In general, the temperature of a furnace in a steel mill is 1,773 K, and the surface temperature of the sun is 6,000 K.

 ▲ KRISS Frontier of Extreme Physics Team

(From left: Le Huu Nhat, UST student researcher; Yong Chan Cho, senior researcher; Sangho Jeon, post-doc researcher; Joohyun Lee, principal researcher)

On June 21, Korea succeeded in the test launch of the Nuri rocket, propelled through fuel combustion reaching a temperature as high as 3,773 K. Even with a cooling device, the metal alloys used in launch vehicles must be able to withstand high temperatures above 3,000 K.

Heat-resistant metals such as titanium and tungsten are commonly used in space launch vehicles, aircraft engines, and nuclear fusion reactors. Their efficiency improves with operating temperature, but for design stability, it is essential to accurately determine their thermal properties as metals expand in volume at high temperatures.

Commercially available instruments used to measure thermal properties rely on the traditional contact method, and support temperatures up to 2,000 K. Since high temperature environment causes unwanted contamination and reaction with surroundings with the traditional contact methods, non-contact methods, such as levitation techniques, should be required for samples under higher temperature condition. Electrostatic levitator (ESL) can provide a way measuring the high temperature thermophysical properties. ESL is owned by leading countries in the aerospace sector, such as the United States, Germany, China, Japan, and Korea.

▲ Main cause of inconsistency in thermal property measurements over 3,000 K based on the KRISS research team’s findings

While thermal property measurements using an electrostatic levitator have been relatively consistent for temperatures below 2,000 K, they are less reliable at higher temperatures with largely scattered data.

The KRISS Frontier of Extreme Physics Team identified the cause of inconsistency in past research based on measurements of thermal properties above 3,000 K, and developed a method of obtaining precise, reliable measurements. The team is the first in the world to conduct high-precision analysis on uncertainties related to thermal property measurements over 3,000 K.

▲ The KRISS Frontier of Extreme Physics Team is measuring the thermal properties of heat-resistant metals under ultra-high temperatures using an electrostatic levitator.

(From left: Joohyun Lee, principal researcher; Yong Chan Cho, senior researcher)

The team levitated samples of niobium (2750 K), molybdenum (2896 K), and tantalum (3290 K) using an electrostatic levitator, and melted them with high-output lasers. They succeeded in repeatedly obtaining precise measurements of liquid density and thermal expansion at temperatures over 3,000 K.

The results provide reference values not only for alloys used in space launch vehicles, aircraft engines, and gas turbines of nuclear reactors, but also enhance the safety and efficiency of metal 3D printing processes.

Geun Woo Lee, principal researcher of KRISS, said, “It was essential to secure novel technology at the national level for aerospace, aviation and defense industries, which have mostly relied on imports. Our results will help raise the standards of local industries that are exposed to extreme conditions.”

KRISS will conduct follow-up research at higher temperatures up to 4,000 K, and based on the findings, develop heat-resistant materials for use in extreme conditions.

Supported by KRISS, the research was approved for online publication in the June issue of Metrologia (IF: 3.157), a prestigious journal in measurement standards.

-  KRISS-POSTECH joint research team develops physics-informed AI acoustic simulation technology -

- Developed technology is useful for real-time detection of sound, noise, and vibration as well as optimization of environmental systems, and thereby applicable to smart factories and digital twins -

The joint research team between Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) and Pohang University of Science and Technology (POSTECH, President Moo Hwan Kim) became the first in Korea to develop an AI technology that directly learns the acoustic physics.

▲ KRISS-POSTECH joint research team

(From left: Seungchul Lee, associate professor of the Department of Mechanical Engineering at POSTECH; Hyung Jin Lee, KRISS senior researcher; Soo Young Lee, POSTECH MS/PhD integrated program researcher)

The new AI acoustic simulation technology can play a pivotal role in predicting real-time changes of sound, noise, and vibration inside a certain system and resolving involved problems. By using the technology, one can conduct the sound/vibration monitoring of various mechanical products, such as household appliances and vehicles, as well as large-scale structures, such as buildings and bridges, and optimize their performances by reflecting decisions derived from the AI simulations. 

The developed AI simulator can be applied to a digital twin technology, which shows great promise in the industrial field. A Digital twin is a virtual replica of an object in reality, existing for simulations of various environmental conditions. Proper moments for repair and maintenance of an actual equipment or system can be efficiently determined by monitoring the performance of a digital twin in the virtual world. A smart factory, which is operated solely by an AI technology covering data collection and factory control, clearly highlight the need of a digital twin.

▲ The joint research team is reviewing experimental results obtained from the AI acoustic simulation technology.

There are two technologies that can be utilized for acoustic simulations of a digital twin at present; one is the conventional AI technology and the other is the engineering simulation technology based on the finite element method. The former works fast and accurately for trained scenarios, but it is significantly weak for unexpected problems. The latter, on the other hand, works accurately, but it is not appropriate for real-time applications due to slow performance. 

The proposed AI acoustic technology overcomes the aforementioned current issues in simulation of a digital twin. The proposed technology shows superiorities over the conventional AI technology in the aspects of a computational accuracy and a handling capability for unexpected problems. Furthermore, the proposed technology achieves an ultra-fast computational performance, which is 450 times superior to the engineering simulation technology.. With the outstanding performances in terms of accuracy and speed even for unexpected problems, the proposed technology is expected to accelerate the commercialization of a digital twin. 

The core mechanism of the proposed AI technology is a physics-informed deep-learning algorithm, which trains the AI neural network to directly learn the physics. The proposed technology derives an accurate analysis even in unexpected circumstances because it can cope with the problems based on the knowledge of physical theories.

▲ KRISS-POSTECH joint research team

Hyung Jin Lee, a senior researcher of KRISS, said, “We can learn a new language through experience, but with an additional training of grammatical rules we can learn it more accurately and efficiently. Our proposed physics-informed mechanism corresponds to the training of grammatical rules. Our proposed technology will create a new paradigm in the AI deep–learning regime specifically for acoustic problems.”

Professor Seungchul Lee of POSTECH said, “Synergy was achieved between KRISS and POSTECH, which specialize in acoustics and AI, respectively. We are now continuing the research to accomplish the actual application of our technology into a digital twin.” 

The study received grants from KRISS and the Institute of Civil Military Technology Cooperation funded by the Defense Acquisition Program Administration and Ministry of Trade, Industry and Energy. The results were published online in Engineering with Computers (IF: 7.963, JCR Top 2.63%), one of the leading journals in mechanical engineering, on April 9.

- KRISS and Sungkyunkwan University develop an electric adhesive patch that allows real-time measurements of ECG and temperature on skin -

- Can be worn for 24 hours without adverse effects, and shows promise for use in medical wearable devices -

Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) and Sungkyunkwan University (President Dong Ryeol Shin) developed a medical silicon electric patch that measures biosignals when attached to the skin.

The key features of this patch are excellent adhesion without the use of chemical adhesives and stretchable electrodes based on carbon nanofibers. It can be used in medical wearable devices for 24-hour monitoring of biosignals, such as body temperature and ECG. 

▲ KRISS-Sungkyunkwan University joint research team

(From left: Da-wan Kim, KRISS visiting researcher at KRISS; Seung-hwan Jeon, SKKU integrated master’s and doctoral program student; Min-Seok Kim, KRISS principal researcher; Gui-won Hwang, SKKU integrated master’s and doctoral program student; Hyeongho Min, KRISS student researcher; Jinhyung Kim, SKKU integrated master’s and doctoral program student)

Medical wearable devices are seeing a growing demand due to population aging, increase in cardiovascular diseases, and expansion of on-line healthcare services. In particular, real-time biosignal monitoring via wearable devices is essential for early detection of symptoms associated with cardiovascular diseases such as myocardial infarction, angina, and arrhythmia.

Currently available electric patches do not stay attached when their adhesive force weakens due to wets and oils on the skin. Chemical adhesives can address this issue, but may cause skin irritations or allergic reactions. Conductive materials are used to deliver biosignals, but conductivity is easily degraded by their low chemical and thermal durability.

▲    Silicon electric patch fabricated with carbon nanofiber electrodes for high stretchability

 To improve upon the aforementioned issues, the joint research team developed an electric patch material with enhanced adhesion even during movement and water penetration by mimicking the microstructure of the forelegs of male diving beetles. The silicon patch can be safely used for long periods on human skin as it is air-permeable and has the ability to drain excess water.

▲ Conceptual diagram of the adhesive patch, inspired by the foreleg structures of male diving beetles

The stretchable electrode of the proposed carbon nanofiber material maintains conductivity even when skin is folded or stretched. The team enhanced durability by embedding the roots of carbon nanofibers into the silicon surface. The patch does not easily separate from the electrode, ensuring stretchability, conductivity, as well as durability.

The team combined the bio-mimic adhesive material, stretchable electrode, and temperature sensor to fabricate a wearable patch. The demonstration showed that the patch remained stably attached after exercise with sweat, and was capable of real-time monitoring of ECG signals and temperature.

The proposed patch is expected to simplify the manufacturing process, lower costs, and facilitate mass production.

Min-Seok Kim, the head of the KRISS Mechanical Metrology Group, said, “Existing medical electric patches were foreign products, and had limited applications in terms of performance. The proposed patch will contribute to remote diagnostics and healthcare, propelling the wearable medical device industry in Korea.”

Professor Changhyun Pang of Sungkyunkwan University said, “We will conduct follow-up research to develop wearable sensors capable of comprehensive diagnostics based on real-time measurements of the four main vital signs—pulse rate, blood pressure, respiration rate, and body temperature—and oxygen saturation.”

Supported by KRISS and the National Research Foundation of Korea, the research outcomes were published in the international journal Chemical Engineering Journal (IF: 13.273), and featured on the back cover of Advanced Functional Materials (IF: 18.808).

▲ Featured on the back cover of Advanced Functional Materials

- Expected to benefit high-performance nanosensors making precise mass measurements -

Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) has developed a technique of generating microwave frequency combs using a superconducting nanoelectromechanical transducer developed in 2021. The frequency combs can be utilized in high-performance sensors that require precise molecular-level mass measurements.

▲ Principal researcher Junho Suh (left) and senior researcher Jinwoong Cha (right) of the KRISS Hybrid Quantum Systems Team

The KRISS Hybrid Quantum Systems Team developed a technique to produce frequency combs by introducing microwave signals into a superconducting nanoelectromechanical device*. A frequency comb is a phenomenon where multiple frequency signals are equally spaced, exhibiting a comb-like appearance. The frequency combs generated by the research team equals to the resonant frequency of the nanomechanical device, and measuring the comb-frequency spacing could allow for precise tracking of frequency changes.

* Superconducting nanoelectromechanical device: A nanoscale device, made of a superconducting material, that allows electrical measurements of mechanical vibration

▲ Microwave frequency combs obtained from the superconducting nanoelectromechanical device

The team placed the device in a liquid-helium freezer to provide a low-temperature environment needed for superconducting performance. A microwave signal generator was used to transmit a single frequency microwave signal to the device, and frequency combs were successfully formed. 

The typical method to measure the frequency of a nanomechanical device is based on optical interference caused by light waves reflected from the device. The frequency of the interference signals from the nanomechanical device must be compared against electrical signals of a certain frequency for real-time tracking. However, this approach requires complex optical and electrical equipment, resulting in poorer measurement performance due to the various noise sources.

▲ Schematic showing the generation of microwave frequency combs in a superconducting nanoelectromechanical device

The principle behind the frequency comb generation is that the resonant frequency of the nanomechanical device can be measured by introducing single-frequency microwave signals, even without the use of complex sets of equipment.

The technique has vast applications in areas requiring precise measurements such as high-performance nanosensors. For instance, the resonant frequency of a nanomechanical device changes when protein molecules are adsorbed because of the change in the mass of the device. It is possible to estimate the mass of the adsorbed material by analyzing frequency comb signals.

Jinwoong Cha, senior researcher of the Hybrid Quantum Systems Team, said, “The frequency comb generation technique will lead to enhancement of the precision by at least a few dozen times that of existing nanomechanical sensors.”

Junho Suh, the principal researcher who also participated in the project, said, “Although this experiment was conducted at ultra-low temperatures to maximize device performance, we aim to realize frequency combs at the room temperature to utilize this technique in industrial applications.”

This study, funded by KRISS, National Research Council of Science and Technology, and National Research Foundation of Korea, was published in the world-leading journal Nano Letters (IF: 12.262) in June.

- Wrinkled graphene adds stretchability to graphene, a dream material, enabling various material applications -

- The study shows promise for industrial applications such as flexible/wearable devices, solar cells, energy devices, sensors, and filters -

The Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) has developed a technique for transferring large-area wrinkled graphene onto polymeric substrates. The transfer of wrinkled graphene was previously limited to specific materials, and the proposed large-area transfer method has broadened the scope of industrial applications.

 ▲ KRISS researchers, examining the wrinkled graphene structure.

(Left: Seong-Gu Hong, principal researcher / Right: Prashant Narute, doctoral student of UST-KRISS School)

Graphene is called the material of dreams because of its outstanding electrical and thermal conductivity and high durability. When a wrinkled structure is formed, it improves various properties, including stretchability, surface area per volume, optical transmittance, wettability, and electrochemical stability, broadening the scope of applications.

Existing methods for fabricating wrinkled graphene involved the use of elastomers with large elastic deformability, or thermoplastic substrates. The substrates are stretched out, and wrinkles form when they contract back to their original size.

This method is difficult to commercialize since it is almost impossible to separate the wrinkled graphene from substrates. The only solution is to dissolve the substrate using toxic chemicals, but this does not work for elastomers. Moreover, it takes at least two days to dissolve a small piece of thermoplastic film. After this process, the wrinkled graphene is no longer suitable for industrial use because of the presence of residual contaminants and damaged structure.

The KRISS research team developed a method of easily separating wrinkled graphene from substrates without damage, and validated the performance of the separated wrinkled graphene after transfer onto polymeric substrates such as PET and PDMS.

▲ Winkled graphene fabrication and transfer onto PET and PDMS

The key idea of this new technique is to add a water-soluble film between the wrinkled graphene and substrate. After coating the substrate with the water-soluble film, the graphene is transferred by the roll-based process. Strong adhesion forms between the graphene and the substrate, which enables control of the wrinkled graphene structure, even for large areas. To separate the wrinkled graphene from the substrate, the film can then be dissolved using water, for transfer onto other substrates.

Using a water-soluble film, the team transferred wrinkled graphene onto PET and PDMS substrates, and then validated its performance. The wrinkled structure was not damaged on either substrate, and no traces of contaminants were found. The resulting films exhibited outstanding optical transmittance, electrical and mechanical properties, and durability. This is the first-ever attempt to transfer wrinkled graphene onto a PET film, which has small elastic deformability.

The applications of wrinkled graphene include smartphones and wearable devices that require flexible transparent electrodes, sensors and filters with high electrochemical reactivity and efficiency, energy storage devices, and solar cells.

▲ Prashant Narute, doctoral student of UST-KRISS School, shows a sample of wrinkled graphene that was transferred onto a PET substrate.

Seong-Gu Hong, principal researcher of the Interdisciplinary Materials Measurement Institute, said, “By employing the roll-based process, which is commonly used in manufacturing, we made the low-cost, large-area utilization of wrinkled graphene in various applications possible.”

This study, funded by KRISS, was published in the international journal ACS Nano (IF=18.027) in June. Patent applications have been filed for the results in Korea and the United States. The first author is Prashant Narute, a doctoral student of the UST-KRISS School, and the corresponding author is Seong-Gu Hong, a principal researcher.

- First Certified Reference Materials targeting diagnostic markers of inherited metabolic disorders in newborn screening -

- Enhanced reliability of dried blood spot samples expected to expand remote diagnosis applications -

# A’s baby underwent a newborn screening test for inherited metabolic disorders within seven days of birth. The test checks for risk factors such as hypothyroidism, phenylketonuria, maple syrup urine disease, which can lead to developmental disabilities if not detected in their early stage. Every year, one in every 1,000 newborns are diagnosed with inherited metabolic disorders.

The Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) has developed Certified Reference Materials (CRMs)* that can enhance the reliability of using dried blood spot testing for newborn screening.

* CRM: A reference material that serves as a standard in determining the accuracy of measurements and analytical methods

▲ KRISS Biodiagnostics Analysis Team 

(From left: Seohyun Choi, master’s student of UST-KRISS School; Ji-Seon Jeong, principal researcher; Ha-Jeong Kwon, principal researcher; Nordiana Rosli, doctoral student of UST-KRISS School)

DBS is a sample obtained by drying a drop of blood from the finger or heel on a piece of filter paper. This approach is used for screening rather than actual diagnosis, as it is less accurate than venous blood sample tests. Its common applications include newborn screening for inherited metabolic disorders and doping control during Olympics. 

▲ DBS CRM for metabolites analysis

The proposed CRM provides eight certified values and 10 reference values for amino acids, glucose, galactose, and acylcarnitines, which are diagnostic markers of inherited metabolic disorders in newborns. This allows accurate measurement of the amount of target compounds in the DBS.

▲ Overview of development of DBS CRMs

The lack of reference values has made it difficult for DBS testing to be considered reliable for medical decision. In addition, there has been a problem with measurement bias caused by the need to retrieve portions of blood spots using a paper puncher.

The KRISS Biodiagnostics Analysis Team found that a 0.4 mm bias in diameter led to a 0.78 μL (one millionth of a liter) difference in sample volume.

▲ A researcher is fabricating the proposed DBS CRM for metabolites analysis.

The research team controlled the sample volume to 50 μL during the CRM manufacturing stage, and proposed bias-free measurements as certified values, thereby successfully creating CRMs with complete measurement traceability to the International System of Units. This is the first-ever development of DBS CRMs.

Dr. Ji-Seon Jeong, a principal researcher at KRISS, said, “DBS has come under the spotlight as a convenient way of blood sampling, which satisfies the high demand for remote healthcare and home sampling in the days of the pandemic. Our study has laid the foundation to improve the reliability in DBS sample measurement, opening the door for DBS to become an effective tool not only in screening but also diagnosis.”

KRISS plans to develop more CRMs for other diagnostic markers used in newborn screening. 

Funded by KRISS, the study was published in the world-leading journal Analytical Chemistry (IF: 8.008) in July.

- KRISS finds the cause of the decrease in damage-containing DNA fragments produced in response to UV and carcinogens -

- Highly sensitive technique for measuring DNA fragments will help research on personalized cancer treatments -

The Korea Research Institute of Standards and Science (KRISS, President Hyun-Min Park) found that the TREX1 protein identified in a genetic screen degrades damage-containing DNA fragments, successfully proving this in vitro.

▲ KRISS researchers who identified the TREX1 enzyme as a major regulator of damage-containing DNA oligonucleotides in vivo (from left: Yunju Song, student researcher; Jun-Hyuk Choi, principal researcher; Geun Hoe Kim, UST student researcher)

DNA damage occurs every day due to UV radiation and due to chemical carcinogens as well. Genetic information is preserved in cells despite such damage because cells have a repair mechanism for damaged bases. DNA damage accumulates if DNA repair is not effective, leading to aging or serious diseases such as cancer.

Damage-containing DNA oligonucleotides are inevitably produced from the DNA repair process. These DNA fragments decrease gradually over time in human cells. If they are not properly regulated, it can cause diseases through inflammation or inappropriate immune reactions. In earlier research, there was no technology capable of analyzing small traces of DNA fragments, and the causes of related decreases remained unknown. The KRISS research team found that the TREX1 protein contributes to the degradation of damage-containing DNA fragments, becoming the world’s first team to prove this in vitro.

▲ Measuring damage-containing DNA fragments produced during the DNA repair process

The research team altered the expression of specific target genes in human cells and then analyzed the abundance of damage-containing DNA fragments. They showed that increasing amounts of TREX1 significantly reduced the amounts of damage-containing DNA fragments. They also purified large amounts of damage-containing DNA along with recombinant TREX1 and showed that TREX1 degrades the damage-containing DNA in vitro.

Jun-Hyuk Choi, principal researcher of the KRISS Biometrology Group, said, “DNA fragments will cause aging and diseases if not properly regulated. The persistent presence of DNA fragments in cancer cells is associated with the development of resistance to cancer therapeutics. This study of the degradation of DNA fragments will be very useful for anti-cancer researchers.”

The team’s success was made possible by KRISS’ highly sensitive techniques for measuring damage-containing DNA fragments in small numbers of cells. In 2015, KRISS developed a novel in vivo assay capable of detecting DNA fragments containing a wide spectrum of causes of DNA lesions (UV damage, chemical carcinogens, and chemotherapeutic drugs). The measurement technique has since been improved to allow high-precision analysis within three minutes of DNA damage. The sample amounts required for detection were also reduced to one-tenth of the original level, which is equivalent to roughly 10 picograms.

* Picogram: A unit of mass equal to 10^-12 grams. An E.coli bacterium has a mass of approximately 1 picogram, and the DNA in the cells of humans in general weighs 6 picograms.

 ▲ KRISS researchers examined DNA damage after exposing cells to various carcinogens.

The unique technique allows for direct comparisons of individual DNA repair activities and thus facilitates personalized cancer treatments by accessing cancer risks or anticancer drug efficacy rates. KRISS plans to develop the technique further for measuring trace amounts of DNA repair products. Thus, the technology for measuring DNA repair activity in individuals will lay the foundation for future clinical applications.

Funded by KRISS and the National Research Foundation of Korea, the research outcomes were published in the prestigious journal Nucleic Acids Research (IF 16.97, first/corresponding author) on April 22. The paper was selected as a Hanbitsa (People Glorifying Korea) paper by the Biological Research Information Center (BRIC). The primary authors are Seon Hee Kim and Geun Hoe Kim, UST master’s students advised by Dr. Jun-Hyuk Choi, and the co-corresponding author is Professor Michael G. Kemp of Wright State University.

and Temperature with Quantum Diamond Sensor

- Multiplexed sensing technology operating in daily environment has wide applicability. -

KRISS has developed a quantum diamond sensor capable of precisely measuring magnetic field and temperature changes.

Unlike other types of quantum sensors, the diamond sensor operates without cryogenic and magnetic shielding, namely in a living environment. Also, it can image the distribution of magnetic field and temperature in microscale. This new technology is expected to make contributions to the cutting-edge industries in Korea. 

▲KRISS Researcher is conducting the self-imaging experiment with the quantum diamond censor.  

A ‘nitrogen-vacancy defect,’** has quantum spin*. When they are produced in a pure diamond, the diamond functions as a quantum sensor. The precise control of the quantum spin in the ‘nitrogen-vacancy defect’ enables sensing small changes of the external environment.

*Quantum spin: Spin is a physical quantity of an electron. The classical analogy of spin is a magnet. Spin-up state can be represented as “0” while spin-down “1”. Quantum mechanics can explain the time-dependent change of the spin states.

**Nitrogen-vacancy defect: Nitrogen is the most common impurity in diamonds. For some reasons, a carbon atom consisting of a diamond lattice may fail to occupy its right location, which is named vacancy. When a vacancy mates with a nitrogen, a ‘nitrogen-vacancy defect’ is formed.

The property of diamond is crucial for a highly-sensitive sensor. The research team investigated the diamonds produced under various conditions, and only the diamonds that has nitrogen concentrations below a certain level were selected. For the optimal performance out of the selected diamonds, the research team devised optical and microwave technologies that are more advanced than the previous studies.

▲The quantum diamond sensor measures magnetic field and temperature. 

The developed quantum diamond sensor is capable of measuring magnetic field at a precision of tens of pT (pico Tesla), which is about 1 millionth of the Earth’s magnetic field, and measuring temperature at a precision of tens of μK (micro Kelvin), which is a millionth of the human body temperature. In addition, with the multiplexed sensing technology, implemented by the research team, magnetic field and temperature change can be sensed simultaneously by using a single sensor. 

The developed sensor can be highly useful in the diagnosis of an object that undergoes a composite change of magnetic field and temperature. Representative examples may include semiconductor devices and lithium-ion batteries; The migration of electrons and ions induces heat and magnetic field production. The damage to the membrane in a battery is invisible from the outside. So, early detection of the heat or the magnetic field caused by the membrane damage using the quantum diamond sensor will help prevent safety accidents.

▲KRISS Researchers are conducting the experiment 

to test the performance of an electron microscope applied the quantum diamond censor. 

The diamond sensor was developed by the Quantum Magnetic Imaging Team at KRISS. Nanophotonic analysis was performed in collaboration with Professor Kwang-Geol Lee’s group at Hanyang University and the theoretical analysis with the QTC (Quantum Technology Center) research group at University of Maryland, US.

Dr. Shim, the leader of the Quantum Magnetic Imaging Team at KRISS, explains, “The precision of the diamond quantum sensor that we developed through the research is close to the world’s highest level. We will conduct further research for a miniaturized diamond sensor suitable for commercialization.”

The research was supported by the Key Research Program of KRISS and the Quantum Sensor Core Technology Development Program funded by the Institute for Information & Communication Technology Planning & Evaluation. The results of the research were published in Physical Review Applied, in last January.

for the analysis of particulate matters (PMs) 

representing urban environmental characteristics of Korea

- The urban PM CRM developed by KRISS is expected 

to allow reliable and traceable measurements of various analytes in PMs or related samples.-

▲The urban particulate matters(PMs) certified reference material(CRM) developed by KRISS 

 KRISS has successfully developed the urban particulate matters (PMs) certified reference material (CRM)* for the analysis of 7 chemical components in the PMs, including harmful elements. The CRM will be used for the quality control and validation of the measurement procedure in the analysis of the PMs, which also allows subsequent use of the data for reliable risk assessment, and source tracking.

▲ (Left) The interdisciplinary research team to develop the urban PM CRM

(Right) The research team members are conducting experiments using the developed urban PM CRM 

The CRM was developed by the interdisciplinary research team** of KRISS. The team procured a large amount of PM raw materials in the Greater Seoul area for two years. The raw materials were processed to obtain homogeneous samples with confined particle size distribution and packaged in an inert condition to guarantee stabilities of the characterized properties. Currently, a few urban PM CRMs are commercially available from the NIST, USA, and the JRC, EU. However, the raw materials of those CRMs were collected in 1970s in USA or Europe with local origins and environmental conditions of the period during the material collection. One of the distinguishing characteristics of the KRISS urban PM CRM is that it better represents current environmental characteristics of the Greater Seoul, Korea.

PMs are small airborne particulates that are invisible to human eyes. Although they have been generated naturally on Earth since ancient times, increasing contamination of various harmful chemicals caused by the industrial activities in the modern era has deteriorated air pollution by PMs and seriously threatened ecological public health. Therefore, reliable measurement of various chemical components in PMs is essential for the evaluation of PM toxicity and the establishment of efficient strategies to minimize PM releases in the environment. Because PMs consist of complex ingredients including elements, organic compounds, and ions of diverse geological/anthropogenic origins, it is challenging to accurately measure individual chemicals in the material. The urban PM CRM developed by KRISS is expected to allow reliable and traceable measurements of various analytes in PMs or related samples by providing efficient means for the quality control of measurement results and the validation of measurement methods. It currently provides the certified values for 7 elements; antimony, calcium, copper, lead, magnesium, tin and zinc. For more extensive coverage of analytes related to PM toxicity and origin identification, more analytes will be included as certified or reference values in the near future.

The Air Quality Intensive Monitoring Stations of the Ministry of Environment periodically monitor the representative harmful components in PMs. The newly developed CRMs can be used for the quality control of the measurement results to improve the reliability of the field measurements. In addition, the chemical composition information obtained from the urban PM CRMs as well as the isotope ratios that will be characterized later can be utilized as a fingerprint for PM sources. The research for the identification of PM sources using the CRMs will be conducted on a full scale after PM CRMs of various origins are completely developed, wherein the origins include roads, subways and incineration plants.

Yong-Hyeon Yim, the leader of the project, commented, “The demand for PM CRMs is drastically increasing in relation to the researches on the toxicology of PMs. We’d like to develop PM CRMs more useful for the toxicology and origin identification researches as well as the environmental monitoring for public health. Our interdisciplinary team will continue our efforts to increase the coverage of characterized properties of the CRMs including harmful organic components, ions, isotope ratios, microbiome information, and the complex patterns of multiple organic components.”

The research was supported by the Internal Research Program of KRISS, and the newly developed urban PM CRM is available in the KRISS E-Shop (https://eshop.kriss.re.kr) from March. /fin./

* Certified Reference Material (CRM): A certified reference material that is the reference material with sufficient homogeneity and 

  stability, characterized by a metrologically valid procedure, which is used for calibrating instruments, performance evaluation or 

  validation of measurement procedures. 

** The interdisciplinary team consists of the Inorganic Metrology Group, Organic Metrology Group, Biometrology Group, Gas Metrology      Group of the Division of Chemical and Biological Metrology, and the Climate Watch and Hydrogen Quality Metrology Team of the 

    Advanced Instrumentation Institute.

Exporting Korean-Made Hydrogen-Powered Electric Vehicles 

- KRISS developed a technology for measuring hydrogen embrittlement in a high-pressure, low-temperature hydrogen environment.

- The technology is expected to help to secure the international certified technology for hydrogen-powered electric vehicles and increase the export to the US and EU.

▲Jaeyeong Park, a senior research scientist of the Safety Measurement Institute at KRISS (left), 

and Un Bong Baek, a principal research scientist of the same Institute, are evaluating the material performance

by using the hydrogen embrittlement measurement system.

The Safety Measurement Institute at KRISS developed a core technology that can facilitate the export of hydrogen-powered electric vehicles manufactured by large companies in Korea.

The Research Team of Material Compatibility to Hydrogen Facility of the Safety Measurement Institute at KRISS developed a system for measuring the hydrogen embrittlement of the metallic materials used for hydrogen-powered electric vehicles in a high-pressure, low-temperature hydrogen environment, and successfully evaluated the performance of the materials.

With the US, Japan and Germany, KRISS has completed international comparison of the technologies for evaluating hydrogen compatibility of metallic materials. Securing the internationally certified technologies for evaluating the performance of the materials for hydrogen-powered electric vehicles will significantly facilitate the export of the hydrogen-powered electric vehicles manufactured by using the Korean-made materials to other countries, including the US and EU.

Materials in contact with hydrogen gas undergo hydrogen embrittlement damage. Hydrogen embrittlement refers to the embrittlement caused by the infiltration of hydrogen to a material, such as a metal, and it causes a fatal damage to the products using hydrogen energy. Safe utilization of hydrogen energy requires sufficient verification of the performance of a material under its utilization environment.

With the recent introduction of environment-friendly hydrogen-powered electric vehicles around the globe, there is an emerging issue about the methodology for preventing hydrogen embrittlement and managing the relevant problems. In particular, since hydrogen embrittlement is directly related with the safety of hydrogen-powered electric vehicles, it is necessary to carry out international performance evaluation and certification.

To preemptively address the issue, the Research Team of Material Compatibility to Hydrogen Facility at KRISS developed system for measuring the hydrogen embrittlement of the metallic materials that are used for hydrogen-powered electric vehicles under low-temperature, high-pressure environmental conditions, and successfully evaluated the material performance.

▲The Research Team of Material Compatibility to Hydrogen Facility at KRISS is evaluating the performance of a material 

by using the hydrogen embrittlement measurement system.

○ In the new technology, a metallic material is pulled in a hydrogen gas environment at –50 ℃ and 875 bar, and the results are compared with the results obtained in the air to measure the hydrogen embrittlement, which is the susceptibility of the material to hydrogen gas. Based on the measurements, the compatibility of the material in a hydrogen environment can be determined.

To internationally compare the testing capability and accuracy, KRISS participated in the international comparison led by the IPHE (International Partnership for Hydrogen and Fuel Cells in the Economy), and conducted international comparison with the US (SNL), Japan (Kushu Univ.) and Germany (MPA Stuttgart).

Recently, US is discussing the legislation of UN GTR 13,* a regulation for securing the safety of hydrogen-powered electric vehicles. The Research Team of Material Compatibility to Hydrogen Facility at KRISS is participating in the discussion as a representative of Korea to present relevant opinions based on the research results. In addition, the Team has completed the research service commissioned by the Ministry of Land, Infrastructure and Transport for the amendment of the relevant standards.

*UN GTR 13 (UN-Global technical regulation No. 13 - Global technical regulation on hydrogen and fuel cell vehicles): An international organization for legislating safety regulations for hydrogen-powered electric vehicles so that anyone can confidently purchase the vehicle around the world and anyone can feel relieved when using a vehicle that conforms to the regulations, seeking the international unification of the relevant laws and regulations.

Un Bong Baek, a principal research scientist of the Research Team of Material Compatibility to Hydrogen Facility at KRISS, said, “We were unable to know if the materials of the hydrogen-powered electric vehicles manufactured by the Korean companies satisfy the relevant standards. Our new technology can secure the relevant basis to remove the obstacle that can be used by the advanced countries, such as Japan, as a technological barrier. This will facilitate the export of the hydrogen-powered electric vehicles manufactured in Korea.”

The research was supported by the Key Research Program of KRISS, and the Program for ‘Development of hydrogen material compatibility evaluation technologies for the pressure vessel & parts of FCEV’ funded by the Ministry of Land, Infrastructure and Transport.

- The thickness and shape of a device are measured 

in a nanometer scale by a nondestructive measurement method. -

- The technology is readily applicable to production sites. As the technology has already been transferred to a Korean company, commercialization of the technology is anticipated. -

▲Dr. Young-sik Ghim, a principal research scientist of the Advanced Instrumentation Institute at KRISS, 

is measuring a 3D nano device. 

The Optical Imaging and Metrology Team at KRISS successfully performed one-shot, real-time inspection of internal device structure, including the structure of semiconductors, displays and sensors.

The highlight of the newly developed technology is that it allows for the measurement of both the thickness and shape of individual internal layers in a nondestructive measurement method without cutting a device. While the real-time nano-device measurement technology, developed by KRISS in 2020, employed a point measurement method and thus could be limitedly applied to thickness measurement, the newly developed technology allows for real-time measurement of both thickness and shape and thus is expected to have higher applicability.

The new technology can be used for accurate single-shot measurement in nanometer resolutions as if directly looking into the cross-section of a device. The new system is less affected by the external environmental conditions such as vibration and temperature and the system configuration is not complicated. Therefore, the system can be easily installed at a production site to perform rapid real-time inspection.

A multi-layered film structure, formed by laminating 10 or more sheets of film, is used as an essential component in the cutting-edge industries, including semiconductor, display and new energy industries, to overcome the limitations related with the high speed and high capacity.

However, the lack of measurement technology for supporting the complicated and advanced manufacturing technologies and processes has caused productivity problems, including the quality issues. The conventional measurement methods have been used limitedly because they can be used to measure either the shape or the thickness. In addition, the measurement methods of directly cutting the device cross-section to observe the internal structure require that the production should be stopped. Therefore, the method could hardly be applied to real-time inspection.

One representative example is the semiconductor process in which highly integrated semiconductors are prepared by laminating various layers. This process requires CMP (Chemical Mechanical Polishing or Chemical Mechanical Planarization) to make each layer planar.

If CMP is not performed appropriately, there is a height variation between the layers with different pattern densities inside the device, decreasing the quality of the semiconductors. Until now, the surface shape has been measured after CMP by a stylus-type contact method. However, the application of the method has been limited due to the scratches generated during the measurement, the risk of breakage, and the long measurement time.

To overcome these limitations of the conventional method, the Optical Imaging and Metrology Team of the Advanced Instrumentation Institute at KRISS developed a new technology for simultaneously obtaining the thickness and shape of the individual layers of a device through a one-shot measurement by simplifying the complicated measurement process. Once the measurement is performed like shooting a photo, it can provide 3D information of the thickness and shape of each layer of a device. Therefore, the technology can readily be applied to industrial sites.

In this technology, a pixelated polarizing camera is used to obtain four different images according to polarizations, and the phase and reflectance of the measurement specimen are calculated from the images. An imaging spectrometer is mounted at the front end of the pixelated polarizing camera to additionally obtain the information at different wavelengths. The measured phase and reflectance information at different wavelengths is put into an independently developed algorithm to separately obtain the film thickness and shape information of each layer. In this way, the internal film structure is prepared as a 3D image.

Young-Sik Ghim, a principal research scientist of the Advanced Instrumentation Institute at KRISS, commented, “We are so happy that we were able to promptly respond to the demand of the industry, including the local production of semiconductor equipment, based on the long-studied source technology of KRISS.” He added, “Our technology for measuring the thickness and shape simultaneously in real time will significantly help to improve the productivity of semiconductors and display devices.”

The new technology was transferred to Nexensor Inc., a company specialized in optical measurement instruments and modules, and the results of the study were published in Optics Express (IF: 3.894), a globally acclaimed journal.

Successful Development of Outreach Mobile Radon Calibration System

- The new system lowered the calibration fee 

and shortened the calibration period to several days.

- The new system allows schools and hospitals 

to use the radon detectors more accurately.

▲KRISS Researchers are operating a mobile radon calibration system   

The Ionizing Radiation Metrology Group of the Division of Chemical and Biological Metrology at KRISS successfully developed a mobile radon calibration system that can reduce the calibration fee to half of the current amount and shorten the calibration period from one month to several days.

Securing the measurement reliability of a radon detector requires calibration, and KRISS is the only institution in Korea that provides the calibration service. The biggest feature of the newly developed mobile radon calibration system is its mobility that allows the calibration service, which used to be carried out only at the calibration laboratory at KRISS, to be performed at the sites where the detector is installed

Radon is an odorless and colorless radioactive isotope that was designated by WHO as one of the Group 1 carcinogens. Since the radon bed incident that occurred in 2018 drew people’s attention to the indoor radon concentration, various radon detectors have been used in the spaces for daily life.

The radon calibration system at KRISS has the world’s highest radon sensitivity and so it allows for precise calibration. Based on the cryogenic solid angle method,* KRISS has an independent primary radon standard.** Through a recent international comparison, the KRISS system has secured international measurement equivalence and maintained the world’s highest measurement uncertainty.

*Cryogenic solid angle method: Measuring alpha particles emitted from radon by adsorbing radon gas to a tip cooled down to 30 K.

**Primary radon standard: A standard for realizing Bq (number of decays per unit time), which is a unit for measuring radioactivity.

Until now, however, a radio detector should be transported to KRISS to receive the calibration service. Due to the high radioactivity of the certified reference material of radon, the calibration service used to take more than one month and required calibration fee over 2.5 million KRW. Another limitation of the service was that a new radon detect could not be added during the calibration.

The Ionizing Radiation Metrology Group of the Division of Chemical and Biological Metrology at KRISS developed a mobile radon calibration system that can reduce the calibration fee and shorten the calibration period. The system, consisting of a radon measurement instrument, a radon source, and a calibration chamber, can reduce the calibration period, while keeping the accuracy as high as before.

This new system enables one to visit a publicly used facility, such as school or hospital, where dozens of radon detectors are installed in a building. The convenience of the on-site calibration service and the reduced calibration period will save the calibration cost and decrease the burden of calibration works. KRISS will implement the new calibration service in the second half of this year to improve the efficiency of radon calibration.

Through the research, the Ionizing Radiation Metrology Group at KRISS acquired Korea’ first source technology for nuclide spectroscopic radon detectors that can distinguish the nuclides of radon and thoron. The technology was transferred in last October, and commercialization is being carried out.

▲The schematic diagram of a mobile radon calibration system

The conventional radon detectors measure radon and thoron together without distinguishing the nuclides. However, the methods for responding to the nuclides are different, because the half-life of radon is about 3.8 days and that of thoron is about 55 seconds. Thoron, having a short half-life, can be reduced by wrapping a plastic bag, while radon can be reduced through ventilation.

Sang-Hoon Hwang, a principal research scientist of the Ionizing Radiation Metrology Group at KRISS, said, “Our new system, which can be used to perform calibration of many detectors at a reasonable price, will contribute to the measurement quality assurance of radon detectors.” He added, “We will develop Korea’s first nuclide spectroscopic radon detector based on the transferred technology transfer to relieve the citizens’ anxiety regarding radon.”

The results of the present study, supported by the Key Research Program of KRISS, were published in Journal of Radioanalytical and Nuclear Chemistry, an international journal in the field of radiation and nuclear chemistry.

- A technology for precisely measuring the internal temperature distribution of 

a material included in a focused ultrasound therapeutic device. -

▲ Yong Tae Kim, a principal research scientist of the Ultrasound Standard Team (left),