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Issue 01, 2019

KRISSNewsletter Research HighlightsDevice for extreme environments... key lies in single material diode

Laboratory generated atmosphere increases accuracy of meteorological observations

Development of Korean genome reference materials

Detecting flexible display defects with one-shot image

The Making of “Warm Ice”

News and EventsKRISS celebrates World Metrology Day 2019

KRISS holds the 17TH KRISS-NMIJ Summit

KRISS holds the 42nd Meeting of ISO/REMCO

Director of VMI visits KRISS

Director of NMCC-SASO visits KRISS

Director of NIST visits KRISS

Issue 01, 2019 _ 2

KRISS Newsletter Research Highlights

Research HighlightsDevice for extreme environments... key lies in single materialdiode- High performance 2D diode made from a single material -

# A diode, which makes current flow in only one direction, is the most

important device in modern electronic engineering. Usually, diodes are

fabricated by heterojunctions between two different semiconductors,

one p-type and the other n-type. Semiconductors are normally given p-

type or n-type characteristics through a process called doping, which

introduces impurities into the material. The devices attain various

characteristics according to device structures and operation modes.

A high performance 2D diode with minimal energy loss thatcould work in extreme environments has been developed atthe Korea Research Institute of Standards and Science.

Dr. Suyong Jung, a principal research scientist of the KRISSQuantum Technology Institute, and his team havesuccessfully developed a vertical diode using just a single twodimensional semiconductor material of tungstendiselenide(WSe2)*, avoiding the conventional p-type and n-type heterojunction method. The technology has resolvedproblems in existing 2D devices, to offer outstandingperformance and stability. In particular, it provides the bestcurrent density among currently existing 2D-basedsemiconductor devices, which means that it can transportthe largest possible amount of charge carriers per unit area.

Lately, active research fields have been focused on using 2D-layered semiconducting materials, which retain theirsemiconductor properties even at a single atomic layerthickness, aiming for high eff icient electronic andoptoelectronic devices.

Until now, conventional p-type and n-type heterojunctionshave been implemented to build 2D layered semiconductordiodes. However, given the nature of 2D materials that aredirectly exposed to external disorders, the imperfectheterojunctions become one of the most crit icalcomponents undermining 2D-based electronic deviceperformances, resulting in lowering operation current partlydue to enhanced Schottky barriers*, contact resistance due

to physical/chemical defects, and unwanted dopings byincomplete junctions.

Dr. Suyong Jung and his team successfully built a stable highperformance diode using only tungsten diselenide(WSe2), a2D layered semiconductor material. Although conventionalmethods are based on forming a heterojunction with twodifferent materials, p-type and n-type semiconductors, thecurrent study utilizes a metal-induced doping method to asingle WSe2 crystal : introduce p-type and n-typesemiconducting properties through direct metal depositionson the two respective ends of the WSe2 material.

The vertical diode developed by Jung’s team features aninsulation layer that retains the original properties of WSe2,sandwiched between the p region and n region. By adjustingthe length of the insulation layer, i.e. the thickness of the thinfilm, diodes with varying device characteristics can becreated.

Another strength of this technology is that the underlyingprinciple of charge transport in the diode relies on quantumtunneling*, which could be used in high-speed electronicdevice applications.

“The vertical diode structure that we’ve developed has asimple device composition, and can be applied to not justWSe2, but a wide range of 2D materials,” says Dr. SuyongJung, adding “the diode can be used in sub-miniature devicesthat can withstand extreme environments, such as extremeheat, extreme cold, and extra high voltage, while minimizingenergy loss. This makes it highly useful for future industrialapplications such as ultrasensitive photodetectors”.

This study and its findings were published in the leadingjournal “Nature Communications” (IF: 12.124) in December,2018.

* Tungsten diselenide(WSe2): A transition metal dichalcogenide, which isa two dimensional layered material that can be separated into monolayerform. It possesses semiconductor properties, with the Fermi level locatedin the middle of its energy bandgap, making it relatively easy to induce p-type or n-type semiconductor characteristics through external doping.

* Quantum tunneling: a quantum physics phenomenon, in which tinyparticles such as electrons or atomic nuclei can pass through barriers offorce fields.

* Schottky barrier: Potential energy barrier occurring in the junctionwhen a metal and a 2D semiconductor, or two different kinds of 2Dsemiconductors, are joined.

Detailed description of research

- Dr. Suyong Jung and his team have built an experimentalsingle crystal WSe2-based vertical diode using the WSe2doping effect at the junction between the contact metaland WSe2, and have determined the WSe2 thin filmthickness dependent quantum charge transport effect.

- The WSe2 optical-electronic device platform built using justa single 2D semiconductor material is not only simple tomanufacture, but also resolves issues associated withexisting p-n type semiconductor heterojunction devicecompositions, achieving measurement reliability andimprovement for precise analysis of device characteristics.

- The team also found that the electron transport propertiesof the vertical WSe2 diode depended on a series ofquantum charge transport phenomena such as directtunneling, Fowler-Nordheim tunneling and Schottkyemission effect, according to the thickness of WSe2.

- The vertical WSe2 diode developed in this study has deviceproperties that can be controlled using just changes to thethickness of the WSe2 single crystals, while utilizing thestrengths of both the Schottkey diode with high currentcapacity, and p-i-n diode with outstanding rectificationproperties, presenting the possibility of a highly efficienthigh performance semiconductor-based diode.

What sets this achievement apart?Using just the singular WSe2 crystal semiconductor material,physical and chemical problems that arise in existing devicesbased on physical heterojunctions of p and n-typesemiconductors are resolved.

As the device works on charge transport based on thequantum tunneling effect, it operates effectively even inextreme conditions such as ultrahigh vacuum and extremecold.

What are its applications?1. Demand for electronic devices that work under extreme

conditions such as extreme heat, extreme cold, extra highvoltage and high radioactivity will keep growing. Thestructurally stable vertical diode with quantum mechanics-based charge transport is expected to be more durableunder extreme conditions compared to existingsemiconductor-based electronic devices.

2. Solar power is a clean and renewable energy source, inwhich electricity is generated through light energyconversion. Solar cells are typically made using p-nsemiconductor junctions. With this technology, solar cellswith a sufficiently large light incident area but minimalenergy loss through metal-semiconductor andsemiconductor-semiconductor contact resistance can befabricated, which presents a wide range of applicability tofuture industries.

Issue 01, 2019 _ 3


▲ Schematic diagram of the tungsten diselenide(WSe2)-basedvertical diode

- (figure on left) Final schematic diagram of WSe2-based verticaldiode /

(figure on right) Singular WSe2-based vertical diode: upper regionhas n-type properties; lower region has p-type properties; between

the two regions is a length-adjustable insulating layer(i).

▲ Dr. Suyong Jung (upper right) and his team are testing theelectron transport properties of the diode.

▲ The KRISS team is preparing to conduct measurements of thevertical diode’s electron transport properties.

Issue 01, 2019 _ 4


# How do meteorologists observe phenomena high up in the sky? They

use radiosondes, which are telemetry instruments that float high up in

the sky on balloons, reaching approximately 35 km above the ground,

to measure meteorological conditions such as temperature, humidity,

and atmospheric pressure. A radiosonde comprises a sensor and a

transmitter, and has the advantage of low cost and weather and

daylight independent observation.

A team at the Korea Research Institute of Standards andScience has successfully developed technology for evaluatingmeteorological observation systems in an environmentidentical to the actual atmosphere, to improve the accuracyof observations.

The KRISS upper air measurement team* has developed anaerological simulation system that can simulate and preciselycontrol meteorological elements such as temperature,humidity, air pressure, solar radiation, and wind speed. Inaddition, the team has also developed technology forevaluating a radiosonde’s temperature measurementcapability to an accuracy of 0.1 ℃ based on the simulationsystem. Using this technology, accurate temperaturemeasurements can be taken from the stratosphere up to 35km above ground. This means that the biggest uncertainty inclimate change forecasting, directly associated with globalwarming and fine dust pollution, can be eliminated.

Temperature is a key primary indicator directly related toclimate change. Temperatures in the troposphere up to 10km ~ 15 km above ground, where air circulates, are used toforecast short term weather trends, while temperatures inthe stratosphere remain stable, and are used in long termclimate change monitoring.

Stratospheric meteorological observations are usually madeby attaching radiosondes to balloons. However, unlike onground, the wind and solar radiation in the stratosphereinterfere with the accuracy of temperature measurement.This is why temperature sensors have to be calibrated sothat the reading matches the actual measured value.

Unti l now, it was diff icult to evaluate radiosondemeasurements accurately, as there was no internationally

recognized method or standard to calibrate the sensorswhile considering the various meteorological factors. Thebiggest challenge when calibrating sensors in the lab wasgenerating constant wind. In the low temperature andpressure conditions of the upper air, the desired windventilation speed cannot be generated by the use of simplefans alone.

The KRISS team has developed an ‘upper air simulationsystem’ and ‘temperature calibration technology’ that allowprecise calibration of radiosondes for various ventilationspeeds and solar irradiance under a wide range ofmeteorological conditions. For the f irst t ime inmeteorological simulations, the team introduced the sonicnozzle*, which sends air flowing at a constant speed underspecific conditions to generate wind.

The system comprises a large chamber installed with a sonicnozzle and air pressure control device to control thetemperature and air ventilation speed. Using the system,radiosondes can be precisely calibrated for altitudes up to 35km and a minimum temperature of -70℃, to an accuracy of0.1℃. This is a high level of precision never before reachedin any country around the world or even by the WorldMeteorological Organization(WMO).

“Radiosondes, which are widely used by the meteorologicaladministration and air force, can now be evaluated accordingto a national standard,” says Dr. Yong-Gyoo Kim who leadsthe team, adding, “this will not only improve the reliability ofmeteorological observation in the country, but also create afoundation for the domestic production of radiosondes,allowing Korea to achieve advanced nation status inmeteorology.”

This research was funded by the KRISS institutional programand the Ministry of Trade, Industry and Energy’s CoreIndustrial Technology Development Project. Its outcomeswere presented at the WMO CIMO-TECO* conference.

Laboratory generated atmosphere increases accuracy ofmeteorological observations- Development of earth atmospheric temperature measurement accuracy assessment

technology -

* KRISS upper air measurement team: A transdisciplinary research teamcomprising Dr. Yong-Gyoo Kim, a principal research scientist of theKRISS Center for Thermometry and Fluid Flow Technology and 10experts in the fields of temperature, humidity, flow, and photometry.

* Sonic nozzle: Specific pressure conditions can be created by making theoutlet of the tube, through which air flows, smaller than the inlet. Sonicnozzles are used to keep the amount air being released through the tubeflowing at a constant rate.

* WMO CIMO-TECO: Biannual conference held by the WMO, with theparticipation of Meteorological Administrations and meteorologistsaround the world.

Issue 01, 2019 _ 5


Radiosonde- Meteorological observation device that can transmit upper

air essential climate variables such as temperature, humidity,air pressure, wind direction, wind speed, ozoneconcentration, etc., to the ground via radio frequencytelecommunication. It is composed of variousmeteorological observation sensors such as temperaturesensors and a GPS module. It is sent up into the sky on alarge balloon about 2 m in diameter, and reaches amaximum altitude of 35 km at a speed of 5 m/s, where ittakes a wide range of meteorological readings.

- The entire observation system comprises a radiosonde,balloon, and wireless ground receiver.

- All WMO member states take regular radiosonde readingsand share them internationally, and the Koreanmeteorological administration takes round-the-clockmeasurements from the Pohang weather station.

What sets this achievement apart?This is the world’s first system to simultaneously simulate thelow temperature low pressure atmosphere of thestratosphere, heating from solar radiation, and air movementfrom the rising balloon. This means that the team hassuccessfully developed the world’s only technology that cancorrect for radiosonde wind and temperature changes fromsolar radiation in the stratosphere.

What are its applications?1. National standard traceable system for meteorological

radiosondes: The performance of radiosondes, which are used constantlyby the meteorological administration and air force, can nowbe verified according to a national standard.

2. Enhanced accuracy of meteorological observations: As temperature readings from radiosondes become moreaccurate, climate forecasts based on these will become morereliable. This means that data relevant to global warming andfine dust pollution will also be more reliable.

3. A new international standard of solar radiation correction: With this technology, it has become possible to basetemperature corrections for solar radiation on accuratemeasurements, rather than correction values provided by themanufacturer. If this technology is accepted by the WMO, allupper air measurements from meteorological administrationsaround the world from the past decades could be corrected.

4. Development of a new radiosonde concept : The findings from this study will be used to develop a newadvanced concept radiosonde that can correct temperatureincreases from daytime solar radiation and temperaturedeclines from nighttime radiation in real time. Currently, astudy to enhance the accuracy of upper air observations usingthe new radiosonde concept with two temperature sensors(DTR, Dual Thermometer Radiosonde) is underway at KRISS.

▲ The KRISS team is conducting joint research with the GermanMeteorological Service (DWD) for radiosonde evaluation.

▲ The KRISS team is operating the upper air simulation system forradiosonde calibration. (From left, Dr. Yong-Gyoo Kim, Dr. Inseok

Yang, and Senior Technician Sunghun Kim)▲ The KRISS team is operating the upper air simulation system for

radiosonde calibration.

Issue 01, 2019 _ 6


# The genome is often likened to a book, comprising the complete set

of genetic information for a living organism. The genome book is made

up of genes, which are comparable to ‘sentences’ in a book, while

genes comprise DNA sequences, which act like letters. An important

feature of the genome books is that they exhibit similar traits within

population groups such as race and nations. This is why we need to

analyze genomes by groups, just as we classify books by genres.

A joint research team between the Korea Research Institute

of Standards and Science and Seoul National University have

developed Asia’s first reference materials, which can be used

to enhance the accuracy of genome analysis.

A joint research team led by Dr. Young-Kyung Bae, a senior

research scientist and Dr. In Chul Yang, a principal research

scientist of the KRISS Center for Bioanalysis, and Dr. Joohon

Sung, a professor of the SNU Graduate School of Public

Health have successfully developed Korean genome

reference materials and built a database of the

corresponding sequence information. The Korean genome

reference materials can be used for customized genome

analysis, which could potentially enable the early diagnosis of

various genetic diseases.

Since 2003, when with the success of the genome project

the secret of the human genome was unlocked, the time and

cost of decoding vast genomic data have been greatly

reduced by next generation sequencing (NGS)* technology.

Currently, individual genome analysis plays a decisive role in

the prevention and treatment of various genetic diseases

from cancer to Alzheimer’s.

In essence, NGS technology involves fragmenting DNA into

small pieces, analyzing them many times, and then

reassembling them according to the genome map. However,

due to differences in testing methods or reassembly

processes, small errors exist between results obtained by

various test centers. Considering that even slight errors can

negatively affect the diagnosis, there has to be a standard for

evaluating the accuracy of NGS.

Reference materials are useful standards for evaluating the

accuracy of a test center, acting like a solution sheet to a

math problem. When a test center is provided with genome

reference materials and sequencing results containing

accurate data, the center can use the information to calibrate

its equipment and improve the accuracy of analysis.

The joint KRISS-SNU team has successfully developed

genome reference materials by standardizing DNA materials

from Koreans. This entails the extraction of DNA from the

cells of Korean subjects, analyzing of the cells, and verifying of

the results using the most advanced technologies. Genome

reference materials have the advantage of being able to

provide not just quantitative DNA data but also qualitative

sequencing data.

With the development of the Korean genome reference

materials, Korean test centers no longer have to import

Caucasian genome reference materials from the US National

Institute of Standards and Technology (NIST). The Korean

genome reference materials are not only more affordable,

they contain over 30% more validated sequence data to

improve the reliability of genomic analysis in Korea.

“The Korean genome reference materials have a wider

validation range than the existing reference materials, being

based on the ‘Korean standard genome map’ developed by

Korean scientists and recognized worldwide,” Dr. Young-

Kyung Bae says, adding, “It will help make genomic analysis

more accurate not just for Koreans but for Asians in general

as well.”

According to Dr. Joohon Sung, “Korean genomic data is

absolutely necessary for the development of preventative

measures and treatments for Koreans,” and “this technology

will contribute to the development of customized diagnostics

for Korean patients by improving the genomic testing

accuracy of domestic test centers.”

Development of Korean genome reference materials- Customized diagnosis for improved accuracy -

* Next Generation Sequencing(NGS): Genome sequence analysis basedon large-scale parallelization to increase data generation. As vastquantities of DNA pieces are parallelized for faster analysis, nextgeneration sequencing has dramatically reduced the cost of genomicanalysis and is being used in a wide range of applications.

Issue 01, 2019 _ 7


This study was conducted with funding from the Ministry of

Trade, Industry and Energy and Korea Evaluation Institute of

Industrial Technology’s “Korean Standard Genome Mapping:

Genome Daedongyeojido Project”.

What are its applications?1. Improved accuracy and quality management in genome

analysis

: Genomic analysis data plays a key role in disease

susceptibility (an individual’s tendency to develop the

condition) prediction, early diagnosis, treatment selection,

prognosis evaluation, etc. Korean genome reference

materials can be used to validate new methods of genomic

analysis and bioinformatic algorithms to improve the

reliability of genomic analysis, which in turn will make

diagnosis more accurate in clinical practice. There could also

be applications in policies for quality management in genome

analysis.

2. Import substitution, increased exports and leadership in

genomic research standards

: The Korean genome reference materials are the first

genome reference materials developed in Asia. Not only is it

a significant step to no longer being reliant on Caucasian

genome reference materials, the Korean materials contain

over 30% more validated sequence data at 70% of the cost.

This also means that they have excellent export potential as

representative Asian genome reference material.

▲ Dr. Young-Kyung Bae is working on Korean genome referencematerial.

▲ The KRISS-SNU team is observing the Korean genomereference material.

(From left, Dr. Joohon Sung from SNU, Dr. Young-Kyung Bae andDr. In Chul Yang from KRISS)

▲ Asia’s first Korean genome reference materials developedby joint research between KRISS and SNU

Issue 01, 2019 _ 8


Detecting flexible display defects with one-shot image- 3D measurement technology to test complex curved surfaces in real time -

# Optical components used in flexible displays, a core component of

foldable phones, as well as smart glasses and VR devices are ‘freeform

surfaces’ with complex forms. With such complex surface forms,

products have to be inspected thoroughly, but defects still occur

frequently, causing concern to the consumer.

A measurement technology that can inspect the form of

complex curved surface components in real time during the

production process has been developed at the Korea

Research Institute of Standards and Science.

Dr. Young-Sik Ghim, a principal research scientist of the

KRISS Advanced Instrumentation Institute is the researcher

behind the 3D freeform surface measurement technology

that can detect surface changes and defects on advanced

components such as flexible displays, automobile exteriors,

ultrathin films for next generation secondary batteries, etc.,

using just a single image. This technology is unaffected by the

shape and size of the object being measured, and can be

installed directly into industrial production lines thanks to the

simplicity of its composition.

Freeform surfaces* are surfaces that are not just flat or

round, but are asymmetrical about all axes. Freeform

surfaces are being applied to numerous products in our daily

lives, as they evolve to become smaller, lighter, and more

aesthetically pleasing from the design perspective.

Freeform surfaces, which previously were mainly used in

large components such as outer shells for aircraft, spacecraft

and vehicles, are now being expanded to high precision

component parts such as displays and semiconductors with

improved fabrication technologies.

However, this means that the problem of defects such as

surface flaws and damage has become more frequent, but

such defects are very difficult to detect using conventional

measurement technologies, which only work on simple

structures and do not have the sub-nanometer level of

accuracy required by freeform surfaces. Another huge

problem is that the measurements take too much time,

making it impossible to respond immediately to various

defects occurring in real time.

Now, Dr. Young-Sik Ghim has developed a ‘real-time 3D

freeform surface measurement technology’ that successfully

resolves these issues and goes beyond the limitations of

conventional technology. With this, real-time surface

inspection of freeform surfaces at highly precise nanometer-

level resolution can be achieved using just a single image. As

the process is not complicated or time consuming, it can be

conducted in real time, making it resistant to changes in the

external environment and thus more accurate.

The process consists of casting an optimized composite grid

pattern on the target, and analyzing the resulting image using

an independently developed algorithm. When the composite

grid pattern is cast on the surface of a product, surface

defects such as flaws and damage are highlighted, making

them easy to detect.

“The technology has been perfected to a high degree with

automation and modularization, so that it can be applied at

any stage in actual production processes,” Dr. Young-Sik

Ghim explains, adding “we hope it will be used as a key

inspection equipment technology in various advanced

industries.”

This technology was transferred to Nexensor, an optical

measurement equipment and module company, for a fixed

royalty of KRW 110 mil. and a running royalty of 2% revenue.

It was also published in the international journal “Scientific

Reports” (IF:4.122).

* Freeform surface: A free curved surface that is asymmetric to everyaxis. Freeform surface technology offers greatly enhanced opticalperformance compared to spherical or aspherical optical surfaces, whilefacilitating smaller and lighter devices that are also aesthetically pleasing.

Images related to the study

What sets this achievement apart?The 3D freeform surface measurement technology

independently developed at KRISS requires only a single

composite pattern image to take measurements, making it

resistant to external environmental noises, and able to take

real-time measurements of even dynamic objects.

Furthermore, it can take precise measurements of various

freeform surfaces at nanometer-level resolution. The KRISS

team also developed an algorithm that corrects for the

distortion of the composite pattern due to changes in

reflectance of the specimen, as well as non-linear response

error of the measurement device, improving the precision by

over 30%.

What are its applications?1. High value-added advanced industries - surface defect

detection in flexible displays, next generation secondary

batteries etc.

: The technology enables ultra-high-speed detection of a

wide range of opaque surface defects that were not

detectable in existing equipment, such as marks, protrusions,

scratches etc. for flexible substrates and next generation

secondary batteries etc. This could be used in the

development of testing/measurement devices for newly

arising market needs in the future.

2. Automobile and shipbuilding industries - visual inspection

: Visual inspection of automobile and ship parts that had to

Issue 01, 2019 _ 9


▲ Result of surface defect detection in ultrathin films forsecondary batteries using 3D freeform surface measurement

technology

▲ 3D freeform surface measurement equipment developed byDr. Young-Sik Ghim

-(top) Testing equipment for small-scale area measurement /(bottom) Robot arm based testing equipment for large-scale area

measurement

▲ Detection of defects in ultrathin films for secondary batteries:Comparison of image from conventional technology (left) and image from KRISS-developed new technology (right)

- Surface defects show more prominently, making them mucheasier to detect.

Issue 01, 2019 _ 10


The Making of “Warm Ice”- Development of ice controlling technology using pressure -

# Can water freeze at room temperature or even higher temperatures

at which ordinary water boils? Formation of so-called “Warm Ice”

maybe an unfamiliar phenomenon to the general public and yet can be

made possible by controlling the crystallization process in which liquid

turns into a solid. In principle, such manipulation could be achieved not

only by changing temperature but also pressure. However, the latter

requires exerting extreme level of pressure (10,000 times the

atmospheric pressure) on water.

The Center for Convergence Property Measurement,

Frontier in Extreme Physics Team at the Korea Research

Institute of Standards and Science succeeded in creating

room-temperature ice and controlling its growth behaviors

by dynamically compressing water up to pressures above

10,000 atmospheres. By systematical ly varying the

compression rates, the research team discovered a sudden

morphological crossover from 3-dimensional to 2-

dimensional ice. Rigorous investigation unveiled the

underlying mechanism of the anomalous growth transition

which is manifested in the forms of shape- and growth speed

changes of ice. Such high-pressure technology and

phenomena can have significant impact on a wide range of

practical applications - biology, foods, medical, and aerospace.

This technology is significant in that the size, shape, and

growth rate of ice can be artificially controlled regardless of

the temperature.

Ice observed in nature has more than 10,000 crystals

including hexagonal plates, columns, and dendrites. Such ice

crystals of various forms induce curiosity about nature as

well as having significant industrial applications. Especially,

controlling ice crystals with pressure rather than temperature

can resolve existing problems of ice, so there is great interest

in this endeavor.

A representative example is foods. When meat is frozen at

regular atmospheric pressure, hexagonal plate ice crystals

with needle-like corners are created, and cause damages of

the cells and tissue. This is why meat from the freezer is less

juicy and does not taste as good as unfrozen meat.

However, when meat is frozen at high pressure, ice crystals

of different shapes that are not sharp in corners are

produced, protecting the quality of the meat.

Ice formed on airplanes can cause aircraft defects and

accidents. On days with snow and at an altitude of 10,000 m,

where the temperature falls below 40 ℃ below zero, iceforms on aircraft wings. When ice crystals are formed

abnormally, the wing shape changes, degrading the lift. Thus,

control of the growth rate and form of ice crystals greatly

affects the safety and operation efficiency of aircraft.

be done manually due to the lack of measurement

technology can be automated.

3. Aerospace and national defense - high precision optical

component inspection

: It will become possible to take 3D surface measurements

of high precision optical components that play a crucial role

in future industries such as satellites and unmanned aerial

vehicles.

▲ Dr. Young-Sik Ghim (right) and his team are checking asmartphone cover glass panel.

Issue 01, 2019 _ 11


Dr. Yun-Hee Lee, Dr. Sooheyong Lee, and Dr. Geun Woo

Lee, principal research scientists of the KRISS Center for

Convergence Property Measurement developed a “real-time

dynamic diamond anvil cell” device that can apply pressures

up to 5,000,000 times that of atmospheric pressure per

second and applied the device to study ice growth under

high pressures. As a result, the research team succeeded in

compressing water at room temperature to produce high

pressure ice and succeeded in transforming 3-dimensional

octahedron ice into a 2-dimensional wing shape ice through

dynamic pressure control. This technology is an independent

technology that can simultaneously measure the pressure,

volume, image, and molecular structure of materials by

integrating driving control and molecular vibration

measurement technologies to the diamond anvil cell, which

implements an extremely high-pressure environment.

The focus of similar research has conventionally been on the

control of temperature and concentration; clear observation

of fast crystal growth was not possible due to time delay

from inevitable thermal and mass diffusion. On the other

hand, pressure al lowed for immediate and uniform

application and overcoming of existing limitations so that the

crystallization process of water molecules can be understood

in detail and controlled.

Dr. Yun-Hee Lee said, “application of high-pressure freezing

technology can lead to new forms of ice crystals and freezing

processes to maintain the taste and freshness of foods.

Applying this technology to the cold chain system currently

used in the logistics of fresh foods is expected to further

improve the marketability of foods.”

Dr. Geun Woo Lee explained that “this technology can be

applied to analyze various crystalline structures; the range of

application fields is infinite.” Also, Dr. Sooheyong Lee

continued, “new material characteristics can be discovered

under extreme environments like those of extremely high

pressure, so science and technologies that have reached

limits can be pushed further towards new dimensions.”

Through support from the Ministry of Science and ICT, this

research accomplishment was published in the “Proceedings

of National Academy of Sciences” (PNAS, IF 9.661), which is

one of the three leading global academic journals.

Detailed description of research

- Real-time, dynamic-diamond anvil cell

High-speed actuation technology was combined with the

conventional technology (diamond anvil cell) to yield

dynamic high pressures by compressing a pair of diamond

anvils with the rate of 5,000,000 times atmospheric pressure

per second.

For the first time in the world, this technology enabled the

simultaneous measurement of pressure, volume, image, and

molecular structure information by integrating

interferometer-based driving control technology, high speed

video recording technology within microseconds time-

resolution, and real-time molecular vibration measurement

technology.

▲ Observation image of the growth formation change of an icecrystal with increasing pressure rate

▲ A magnified view of the diamond anvil cell to produce dynamichigh pressures

Issue 01, 2019 _ 12


What are its applications?1. Foods, bio, medical - high pressure refrigeration, high

pressure sterilization technologies, etc.

: The hexagonal ice crystal formed at low temperature is an

acicular structure that destroys the meat quality or tissues

when freezing meat or vegetables, but ice produced at high

pressure does not show such characteristics. Also, at high

pressure, sterilization is possible, so the quality of products

can be maintained and the transformation of proteins using

high pressure can contribute to drug development.

2. Aerospace field - aircraft icing phenomenon control

: At altitudes of 10,000 m, icing occurs on the wings of

aircraft and this abnormal ice crystal growth can lead to

changes in the aircraft wing shape, reducing the lift. So, the

ice crystal growth rate and shape control are important

factors in aircraft safety and operation efficiency.

3. Explorations of the deep parts of Earth and lifeforms on

alien planets

: Fish that live in ocean depths with high pressure and low

temperature such as the Mariana Trench, and organisms that

live in extremely cold environments like the tundra, continue

to live on without freezing in such extreme environments.

For exploration of Mars, an igloo or icehouse was proposed

to withstand the radiation and extreme temperatures.

Similarly, this research provides a method of predicting the

form of water or ice existing in the extreme environments

on Earth or alien planets.

▲ Dr. Yun-Hee Lee(right) and Dr. Geun Woo Lee(left) areadjusting the high-speed camera used to observe the ice growth in

real-time.

▲ Dr. Yun-Hee Lee is aligning a laser for measurement of thepressure and molecular vibration within the anvil cell.

Issue 01, 2019 _ 13

KRISS Newsletter News and Events

News and Events

On May 20, KRISS celebrated World Metrology Day2019 in the administration building of KRISS Campus.This year’s ceremony was to mark the redefinition and its

off icial enactment of 4 SI base units - ki logram(kg),

ampere(A), kelvin(K), and mole(mol) - which is expected to

bring further advancements in measurement science and

technology, so the theme of World Metrology Day 2019

was “The International System of Units -

Fundamentally better”.

Dr. Sang-Ryoul Park, the president of KRISS, put

an emphasis on KRISS’s role to realize and

disseminate the newly defined SI units at his

opening remarks. Also, many distinguished

guests, including Dr. Miock Mun, the 1st Vice

Minister of the Ministry of Science and ICT,

delivered congratulatory remarks to celebrate

this monumental event. In addition, KRISS made

a special video ‘Perfect Units’ and

commemorative stamps with Korea Post to raise

public attention.

For the last program of the ceremony, Dr. Sangwook Kim, a

professor in Physics at Kyunghee Univ. and Dr. Jinhan Kim, a

principal research scientist at KARI(Korea Aerospace

Research Institute) delivered invited talks on the interesting

story behind the SI units, and the new space era and

development of rocket engines.

KRISS celebrates World Metrology Day 2019

KRISS hosted the 17th summit with NMIJ(National

Metrology Institute of Japan) in Jeju on May 28. Dr.

Sang-Ryoul Park, the president of KRISS and Dr. Takashi

Usuda, the director general of NMIJ, and all the delegates

from both institutes discussed a wide range of

agenda items, including quantum electrical

standards, non-destructive measurement, strategy

and policy making process and activities, etc.

Especially, the two sides, taking the note of the

importance of their cooperation in the field of

quantum electrical standards, agreed to step up

substantive cooperation to make fruitful research

results. They also expressed expectations for the

active participations of their researchers in

upcoming events such as ACRM 2019 and

IMEKO 2021 World Congress which will be

held in Japan.

KRISS-NMIJ Summit is seen to have served as a useful

opportunity to reaffirm a close cooperation between the

two NMIs and to explore more ways to strengthen it.

KRISS holds the 17TH KRISS-NMIJ Summit

Issue 01, 2019 _ 14


The 42nd Meeting of ISO/REMCO(International

Organization for Standardization/Committee on

Reference Materials) hosted by KATS(Korean Agency for

Technology and Standards) and organized by KRISS was held

in KRISS from June 10 to 13.

It was the very first time that the meeting of

ISO/REMCO was held in South Korea, and 38

scientists from more than 10 countries, including

Dr. Byung joo Kim, Dr. Ki Hwan Choi, Dr. Young

Kyung Bae, and Dr. Jonghwa Lee from KRISS,

participated in this meeting

This year’s meeting aimed for discussing how to

activate the application of reference materials

and to cooperate globally. They also discussed

the establishment and revision of the

international standard documents regarding the

production and application of reference

materials.

KRISS, along with KATS, will share the results of this meeting

with related organization and companies, and encourage

related industries to use reference materials in order to

secure reliability.

KRISS holds the 42nd Meeting of ISO/REMCO

Dr. Cao Xuan Quan, the director of VMI(VietnamMetrology Institute) and his colleagues visited KRISS onJune 10. This was the second consecutive year that the

director of VMI and its delegation visited KRISS.

This visit was arranged upon the request of VMI

to discuss the set-up of standards and facilities of

gas analysis in VMI modelled on the KRISS

system. In this regard, the delegation of VMI had

the laboratory tour of the Center for Gas

Analysis guided by Dr. Jin Seog Kim. They also

had in-depth discussions on the establishment

plan of gas analysis system and the staff training

plan for VMI.

Dr. Sang-Ryoul Park, the president of KRISS

expressed his high expectations that KRISS and

VMI would make a closer cooperative tie

through this cooperation. Dr. Cao Xuan Quan

also replied that further technical support should

be needed not only in set up of this gas analysis system but

in other fields of measurement standards systems.

Director of VMI visits KRISS

Issue 01, 2019 _ 15


Dr. Majed N. AlHarthi, the general director of NMCC-SASO(National Measurement and Calibration Center-Saudi Standards, Metrology and Quality Organization) and

his colleagues visited KRISS from June 26 to 27.

This visit was arranged to discuss the establishment of new

flow measurement laboratories in SASO in conjunction with

the technical support of KRISS. SASO is taking

steps to build the national primary level

laboratories in Saudi Arabia.

The delegation of NMCC-SASO engaged in an

intensive discussion on technical review of its

proposal and detailed specifications. They also

had the laboratory visit to the Center for

Thermometry and Fluid Flow Metrology in order

to look around relevant facilities which they are

trying to model on.

On the sidelines of their visit to KRISS, Dr. Saad

O. Al-Kasabi, the governor of SASO and Dr.

Sang-Ryoul Park, the president of KRISS, signed

the “Technical Cooperation Program concerning

Cooperation in the Field of Flow Measurements

Laboratories” in Seoul, on June 26.

The two sides agreed to continue working on this issue and

KRISS will conduct on-site consultations in SASO within this

year.

Director of NMCC-SASO visits KRISS

Dr. Walter Copan, the director of NIST(National Instituteof Standards and Technology), and his colleagues visitedKRISS on June 28 as the third leg of his visit to NMIs in East Asia.

The delegation of NIST and the KRISS management with Dr.

Sang-Ryoul Park, the president of KRISS, firstly shared the

current status of each institute and engaged in

discussion on their research cooperation on

quantum technology. NIST and KRISS have

cooperated in the standardization of

photocatalytic activity assay and the

development of advanced superconducting

Josephson. The delegations from the two sides

reviewed the progress in each research and

discussed further plans.

NIST delegates paid a visit to some labs

including Quantum Technology Institute, Center

for Mechanical Metrology, Center for Nano-Bio

Measurement, and Center for Gas Analysis. In

particular, Dr. Walter Copan gave high marks to the facility

of gas analysis and its technology.

In the wrap-up discussion, the two leaders agreed to step up

joint efforts to discover various issues of mutual interest and

expressed their hopes for promoting them.

Director of NIST visits KRISS

To subscribe, please contact: Ms. Jaewon KimPhone: +82-42-868-5445 Fax: +82-42-868-5444 E-mail: [email protected]: http://www.kriss.re.kr/eng Address: 267 Gajeong-ro, Yuseong-gu, Daejeon 34113, Republic of Korea

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