Issue 02, 2018 · metamaterial, the phase at the end is the same as the phase before entering. This is why the wave appears to be continuous and undistorted. Moreover, the wave can

SRESEARCHKorea Research Institute of

Standards and Science

kgINSTITUTEKorea Research Institute of


mSTANDARDSKorea Research Institute of

Standards and Science ASCIENCEKorea Research Institute of


K KOREAKorea Research Institute of


mol

cd

Issue 02, 2018

KRISSNewsletter

http://www.kriss.re.kr/eng

Research HighlightsDiscrimination of single nucleotide mismatches enables early cancer diagnosis

Underwater stealth technology becomes possible

KRISS commercializes an interferometric sensor to detect defective glasses

Development of trimer atom based gas field ion source for ion microscopy

Towards realization of invariant resistance standard at mega-ohm level

News and EventsKRISS attends the 16th NMIJ-KRISS SUMMIT in Japan

President of INMETRO visits KRISS

KRISS holds the International Symposium of Standard Reference Data (ISSRD) 2018

KRISS holds the Emerging Scientist Workshop 2018

Issue 02, 2018 _ 2

Research HighlightsKRISS Newsletter

Research Highlights

Discrimination of single nucleotide mismatches enables earlycancer diagnosis- Low-cost, high-sensitivity miRNA sensor developed -

RNA molecules in the human body express protein

according to genetic information in DNA. A microRNA

(miRNA) is a small RNA molecule that suppresses protein

expression of other RNA, thereby playing a key role in all

stages from cell birth to death.

A research team of KRISS developed a low-cost, high-

sensitivity sensor capable of accurately detecting miRNA

in human tissues.

Led by principal research scientist Tae Geol Lee of the

Center for Nano-Bio Measurement, the team succeeded in

developing an LSPR*-based highly-sensitive miRNA

sensor through simple enzyme reactions. The sensor allows

quantitative analysis, distinguishing between sequences

with single nucleotide differences, and is expected to have

diverse applications in cancer diagnostics and evaluation of

anti-cancer drugs.

miRNAs are RNA molecules with short sequences (about

22 nucleotides), and there are many kinds of miRNAs in

human cells and they are known to play various roles.

miRNAs do not contain genetic information but bind with

RNAs to suppress protein expression. They are closely

related to various biological phenomena since they affect

protein expression.

Recently, the academia has been focusing on early

diagnosis of diseases based on the unique miRNA

properties. For instance, cancer patients have an excessive

number of miRNAs, which bind to tumor suppressing

genes in the body. These miRNAs inhibit the production of

proteins that interfere with the growth of cancerous cells.

The detection of specific miRNAs can be used as an

indicator for early diagnosis of diseases.

Quantitative analysis and accuracy with high sequence

specificity are essential for miRNA sensor as miRNAs

assume completely different functions with a single

nucleotide substitution. Currently, PCR is a widely used

method to analyze miRNAs. However, PCR requires gene

amplification and additional labeling, and such

modifications lead to less accurate results.

By utilizing LSPR technology, Lee and his team succeeded

in developing a highly-sensitive miRNA sensor that does

not require labeling or gene amplification. Thanks to its

high sequence specificity, the device can distinguish

between sequences with only a single nucleotide

substitution.

To overcome the weak wavelength shift, which is an issue

with current LSPR technology, the team induced selective

enzyme reactions on the gold nanostructure surface of the

sensor. Reproducible signal changes with high sensitivity

were obtained by generating wavelength changes larger

than the current standard by several dozen times.

* Localized Surface Plasmon Resonance (LSPR): An opticalphenomenon resulting from the interactions between aplasmonic nanoparticle or nanostructure and light of aspecific wavelength.

Lee(back) and his team developing the highly-sensitivemiRNA sensor


Issue 02, 2018 _ 3

SEM images of the nanostructure surface before (left) and after (right) enzyme reactions

Wavelength shift is not significant before enzyme reactions(left), but becomes more pronounced after enzymereactions(right), allowing easier miRNA detection

Lee said, “The sensitive and sequence-specific miRNA

sensor developed by KRISS can be applied to various

analytical platforms in the medical industry as it is highly

efficient and reproducible. The sensor can be produced at

half the cost and on a larger scale, thus showing promise in

commercialization.”

Supported by the Biomedical Technology Development

Project of the Ministry of Science and ICT, the study was

published in Biosensors and Bioelectronics on May 1.


Issue 02, 2018 _ 4

Underwater Objects, which cannot be reached by

electromagnetic waves or radar, are detected based on

reflected acoustic waves. Acoustic waves are reflected off

the surface of an object. However, there is a new material

that allows acoustic waves to pass through, remaining safe

and undetected.

A research team composed of Wonjae Choi, a principal

research scientist at the Center for Safety Measurement of

KRISS and Semyung Wang, a professor in the Department

of Mechanical Engineering of Gwangju Institute of Science

and Technology (GIST, President Seung Hyeon Moon),

developed a double-zero-index metamaterial and

successfully conducted experiments in a water tank.

Recently, metamaterials have come under the spotlight as

they exhibit properties that cannot be obtained by natural

materials. A good example is metamaterial cloaking.

Invisibility cloaks control light refracted in the positive

direction, and can even achieve negative or zero refractive

index.

The above can also be applied to acoustic waves. Similar to

how invisibility is achieved by controlling the refraction of

light, underwater stealth capabilities can be attained

through acoustic waves having zero refractive index.

However, underwater acoustic waves with double-zero

refractive index have only been realized in computer

simulations. This is because of the hypothesis that

refractive index can only be controlled when the matrix is

the slowest material.

The team, composed of members of KRISS and GIST,

presented results that overturn the slow material hypothesis.

Double-zero-index phononic crystals* were obtained

through arrays of copper, which is three times faster than

water with regard to transmission rate. The proposed "fast

material hypothesis" is not in complete opposition to the

existing hypothesis, and can be explained through the

symmetry of the lattice structure. The results are expected

to serve as a theoretical basis for future studies on zero

refractive index.

When an acoustic wave passes through a zero-index

metamaterial, the phase at the end is the same as the phase

before entering. This is why the wave appears to be

continuous and undistorted. Moreover, the wave can

converge or diverge depending on the end shape of the

metamaterial.

Choi said, "By using metamaterials for the surface of

submarines, we can create stealth submarines that cannot

be detected using acoustic wave sensors." Professor Wang

of GIST said, "Since sound can be controlled in the desired

directions, the process can be applied to not only

mechanical and medical industries, but also to solve noise

pollution caused by construction sites."

Supported by the Creative Fusion Research Project of the

National Research Council of Science and Technology, the

study was published in the leading journal Scientific

Reports (IF: 4.259) in May.

* Phononic crystal: A periodic arrangement of a unit celldesigned for the purpose of acoustic control

Underwater stealth technology becomes possible- Double-zero-index metamaterial passes acoustic waves without reflection -

Choi (bottom) and his team conducting the double-zero-index metamaterial experiment in a water tank


Issue 02, 2018 _ 5

Research applications

1. Logistics: Stealth submarines

·Acoustic waves are used to detect the location of fish or

submarines underwater. Stealth submarines, which

allow acoustic waves to pass through instead of being

reflected, can be designed using zero-index

metamaterials.

2. Acoustics: Design of optimal sound source

·Standard sound sources, in the form of square or plane

waves, are required to test acoustic systems and sensors.

Ideal sound sources can be produced using zero-index

metamaterials and utilized as standard sound sources.

3. Construction/machinery: Noise and vibration control

·The level of noise in buildings or machines should be

minimal. Using zero-index metamaterials, noise and

vibration can be diverted to other directions. Energy

harvesting can be employed to capture energy while

reducing vibration at the same time.

Double-zero-index metamaterial experimental setup andresults.

- (a) Experimental setup (b) Simulation and experimentalresults with and without the metamaterial

: Plane waves having the same phase generated withmetamaterial

Schematic of phase of plane waves-ex) When the phase of a wave entering a metamaterial is 1,

the phase when existing the end of the zero-indexmetamaterial is also 1.

(Wave shows no changes if there is no metamaterial)


Issue 02, 2018 _ 6

Flat-panel displays sold in the Republic of Korea have

grown by an average of 10 inches over the past seven years.

As manufacturing process becomes more complicated

along with unexpected variables, it is quite difficult to

maintain low level of a defect rate of large glass panels. For

this reason, strict inspection is required during the whole

manufacturing processes.

KRISS developed a robust technology detecting defects of

large glass panels, and then has commercialized a thickness

measuring sensor successfully by transferring the

technology to a company specializing in optical inspection.

A team led by Jonghan Jin, principal research scientist of

the Center for Optical Metrology at KRISS, developed a

sensor capable of measuring physical thickness and

refractive index of large glass substrates in real-time, even

under the strong vibration conditions.

As customers prefer ultra-large screens of their flat-panel

displays, the demand on large bare glasses has been

increasing, which leads the expansion of the related market.

Owing to size of the large bare glasses over several meters,

the production of the glasses having uniform thickness is

not an easy work. Irregular form of the glasses caused by

thickness variation may damage image pixels and distort

images.

Under harsh environmental conditions with strong

vibration, however, conventional inspection machines have

been rarely worked in production lines.

The team led by Jin developed a sensor capable of

measuring physical thickness and refractive index of large

glass substrates in real-time, which works based on optical

interferometry. With the adoption of transmissive

configuration, the sensor achieves the world's best technical

performance in terms of vibration insensitivity without

degradation of measurement accuracy.

Another novelty of this developed technology is to measure

the refractive index of bare glasses. Since optical

interferometers provides only optical thickness, the

conventional interferometric techniques need to know the

refractive index in advance to extract the physical thickness

from the optical thickness. On the other hands, the newly

developed sensor can measure physical thickness and

refractive index at the same time.

Jin said, “The measurement technology is optimized to

apply for the manufacturing process of glass substrates

being used in a wide range of IoT-based products. We have

realized simultaneous measurements of physical thickness

and refractive index under strong vibration conditions,

which is not possible with other conventional sensors.”

In 2017, KRISS transferred the technology to Novitec

specializing in optical inspection. Novitec has succeeded in

commercialization, and signed a product supply agreement

with a global glass manufacturer in July 2018.

Junyoung Lee, the CEO of Novitec, said, “We have

developed an outstanding product thanks to technology

developed by KRISS, and supplied it to a global company.

We are planing to expand our business territories and go

into global markets, not only for glass substrates, but also

solar panels and silicon wafers.”

KRISS commercializes an interferometric sensor to detectdefective glasses- Development of a sensor for measuring thickness and refractive index of large glass panels -

Jin (far right) and his team measuring the physicalthickness and refractive index of a large glass panel


Issue 02, 2018 _ 7

In the world of microscopy, quality depends on beams such

as light, electrons, and ions. How such sources are utilized

determine the performance of microscopes. Higher-

resolution images can be obtained when beams are

concentrated to a small area and then emitted.

KRISS developed novel ion beam* technology for helium

ion microscopes, which are recognized as next-generation

microscopy.

The research team led by In-Yong Park of the Photon and

Electron Instruments Team at KRISS designed an ion

source device*, and succeeded in generating ion beams

with a trimer atom probe.

Helium ion microscopy not only offers sub-nanometer

resolution, but is also suited for precision manufacturing of

dimensions less than 10 nanometers. For this reason,

helium ion microscopes have diverse applications in

various fields including nanoprocess technology, materials

science, and biology.

Ion sources must be precisely designed to achieve high

resolution in helium ion microscopy. The area over which

ion beams are emitted is made smaller by sharpening the

probe tip. The key to a sharp probe tip is to leave a minimal

number of atoms at the tip.

High-performance ion beam technology is very important

in ion microscopy, but commercial microscopes with trimer

atom probes are made by only a handful of international

companies due to their technical complexity.

A major element that interferes with probe tip fabrication is

the oxide film. When the probe is exposed to air before

Development of trimer atom based gas field ion source for ionmicroscopy- Advances in ion beam technology with reverse use of oxide film -

Park (back) and his team performing the trimer atom etching test

* Ion beam: A charged particle beam comprised of ion. An ionmicroscope uses an ion beam as its source.

* Ion source device: A device that generates ion beams by ionizing inactivegases surrounding the probe when a strong positive voltage isapplied after introducing inactive gases such as helium, neon,and xenon

A sensor capable of measuring physical thickness and refractive index of large glass substrates at real-time, which is commercialized based on measurement technology developed by KRISS

entering the vacuum environment, an oxide film forms on

the tungsten surface. In the past, this oxide film was

removed through heat treatment of the probe.

Park and his team succeeded in developing a trimer atom

probe by making use of the oxide film, which was

previously removed by applying heat to the insulating

layer. The team used the oxygen in the insulating layer for

etching, allowing the probe to have a sharper tip.

The significance of this study is that it lays a foundation to

develop more advanced microscopes without relying on

exports. Since heat treatment is no longer necessary, ion

beams can be generated more conveniently and efficiently.

Park said, “The ion beam technology reduces the number of

steps involved compared to existing equipment. It is

expected to significantly enhance the competitiveness of the

local market, which is dominated by imports. Our ultimate

goal is to develop a single atom probe that uses only a single

atom to achieve three times greater brightness.”

Supported by the Nanotechnology Development Project of

the National Research Foundation of Korea, the study was

published online in the June issue of the leading journal,

Ultramicroscopy.


Issue 02, 2018 _ 8

Comparison of multi-atom ion source (left) and trimer atom ion source device (right)

- The multi-atom probe before etching (left) emits ion beamsin various directions over a large area,

while the proposed probe (right) emits high-brightness ionbeams over a very small area (three atoms).

Fabrication of the trimer atom probe using the ion sourcedevice

- Etching of the probe to the size of three atoms using oxygenin the insulating layer

Towards realization of invariant resistance standard at mega-ohmlevel- National competitiveness in metrology demonstrated through Korea-Japan collaboration -

KRISS has played a pivotal role in the realization of

invariant high resistance, which may serve as a standard at

MΩ-level.

A team led by principal research scientist, Dong-Hun Chae

of the Center for Electromagnetic Metrology at KRISS has

contributed significantly through precision measurements

of quantum Hall resistance array to the realization of 1 MΩΩ*

quantum resistance. The study, conducted jointly with

Japanese researchers at the National Metrology Institute of

Japan (NMIJ), verified for the first time that high resistance

values derived from a quantum Hall resistance array remain

unchanged over time.

Resistance, the basic element of any electronic circuit, is

required for the operation of electronic devices. Resistance

* 1 M : 1,000,000 ohm (Ω). Ohm (Ω) is the unit of electricalresistance.

standards ensure that resistance values are accurate and

reliable. Many industries have adopted resistance standards

because deviation from required resistance affects both

current and voltage, leading to fatal functional problems in

products.

The standard of resistance is based on the Quantum Hall

effect* discovered by German scientist, Klaus von Klitzing

in 1980.

Advances in science and technology, however, presented

another challenge. Despite the increased demand for MΩ-

level resistance, the quantum Hall resistance at 12.9 KΩwas inadequate as a standard for high resistance. For this

reason, artifactual metal resistors are used for high

resistance standards.

To realize an invariant high resistance, NMIJ fabricated a 1

MΩquantum Hall resistance array by connecting about 90

resistors in series and parallel. They faced challenges in the

precise validation of the 1 MΩ array resistance due to the

100 times smaller applied current for precision

measurements compared with the quantum Hall resistance

standard. NMIJ requested KRISS, which is capable of the

resistance metrology in the top flight, to participate in a

joint study to overcome this issue.

Chae and his team succeeded in experimental

demonstration that the array resistance is invariant with

time within the relative measurement uncertainty of 10-8

using a Cryogenic Current Comparator. Similar to the act

of placing two loads on a weighing scale, the team directly

compared the proposed quantized Hall array resistance with

the quantum Hall resistance standard.

The MΩ-level invariant quantum-mechanical resistance

opens up new possibilities in science and across industries.

This is because a quantum mechanical high resistance is

needed for the precision measurement of a small current

source and its stable generation. It is expected to drive

technological innovation in precision measurements over

various areas including, for instance, the determination of

density of particulate matter and the radiometry in cancer

treatment.

Chae said, “Quantum Hall array resistance can be utilized in

various industries and research areas directly related to the

lives of citizens. It can be also applied to the precision

evaluation of single electron current sources, which may play

an important role in a realization of the new SI ampere (A).”

The study was published in the October issue of

Metrologia, the leading international journal on metrology

published by the International Bureau of Weights and

Measures in Paris.


* Quantum Hall effect :A phenomenon in which the Hall resistance is quantizedwith respect to the magnetic field arising from the quantummechanical wave nature of electron. This effect is distinctlydifferent from the linear magnetic field dependance of theclassical Hall resistance stemming from the Lorentz force.Quantized Hall resistance is used as the resistance standardbecause it is reproducible and can be calculated with onlythe electron charge and the Planck constant.

Professor Klaus von Klitzing mentioning the precisionmeasurement data acquired at KRISS in the Conference

on Precision Electromagnetic Measurements (CPEM)held in Paris, France last July

Chae preparing the precision measurements of thequantized Hall array resistance

Issue 02, 2018 _ 9

News and EventsKRISS Newsletter

News and Events

Issue 02, 2018 _ 10

KRISS attends the 16th NMIJ-KRISS SUMMIT in JapanKRISS attended the 16th NMIJ-KRISS Summit on July 10 in Sapporo, Hokkaido, Japan. Seven delegates from KRISS

including Dr. Sang-Ryoul Park, President of KRISS, participated in this summit.

KRISS and NMIJ shared current status, R&D activities, and strategic plans of each institute. KRISS presented the research

highlights in the field of advanced instrumentation and quantum technology. Also they discussed cooperation package

regarding common research interest and the way of promoting the redefinition of the SI unit.

KRISS and NMIJ have had annual summit since 2003 in order to share the views on global metrology issues and discuss the

future strategy for bringing advancement as well as harmony in metrology community in globe.

President of INMETRO visits KRISSProf. Carlos Augusto de Azevedo, the President of INMETRO (Instituto Nacional de Metrología, Qualidade e Tecnologia) and

its director of International Cooperation visited KRISS on August 31.

KRISS and INMETRO have collaborated on the exchange of technical information, nanometrology, and other fields of mutual

interest since the MoU between KRISS and INMETRO in 2011, and for further cooperation they discussed the renewal of this

MoU in this meeting. Also, they discussed how to actively enhance the research cooperation between institutes and then visited

three laboratories in KRISS, which are the center for optical metrology, electromagnetic metrology and Watt Balance team.

Based on the visit in August, KRISS and INMETRO signed the MoU on November 14 during the 26th CGPM and agreed to

widen the cooperation including the areas of life science.

News and EventsKRISS Newsletter

Issue 02, 2018 _ 11

KRISS holds the International Symposium of Standard Reference Data (ISSRD) 2018KRISS held the International Symposium of Standard Reference Data (ISSRD) 2018 from September 11 to 12 in Seoul, Korea.

At this year's ISSRD, under the main theme "For the Value of Reliable Data", over 100 experts in standard reference and data

science were invited to discuss the value expansion through improvement of data reliability and the role of reference standard

and measurement standard.

Especially in the plenary session on first day, Dr. Anne. L. Plant and Dr. Rober Hanisch from NIST delivered invited talks on

data science. Also, there was a round-table conference on data standard with NIST, NCSRD(National Center for Standard

Reference Data), KISTI(Korea Institute of Science and Technology Information), NIA(National Information society Agency)

and KDATA(Korea DATA Agency) in order to share further related issues and policies.

KRISS holds the Emerging Scientist Workshop 2018KRISS hosted the 4th Emerging Scientist Workshop (ESW) from September 12 to 14 at KRISS, Daejeon, Korea. ESW, which

started in 2015, is an annual international event that aims for sharing knowledge and experiences and deepening the cooperation

between young researchers of NMIs in APMP region. This year, about 40 young researchers from KRISS(Korea), NIM(China),

and NMIJ(Japan) participated in this workshop.

On its first day, KRISS invited Dr. Anne Plant and Dr. Robert Hanisch from NIST(USA) and they delivered invited talks on the issue

of the importance of data reliability and the data science which was very informative for young metrologist. In addition, there were

flash presentation and poster session which lead ESW participants to actively introduce and discuss their up-to-date research activities.

On the following day, ESW participants got a chance to visit three labs in KRISS in accordance with their respective research interest

which are Watt Balance, Quantum Electrical Standard, and LINAC, and had time to seek for deepening research cooperation.

On its final day, participants got some time for in-depth discussion as well as field trip including visit to industries & research

institutes which are closely related to KRISS activities.

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

Better Standards, Better Life

Documents

Issue 02, 2018 · metamaterial, the phase at the end is the same as the phase before entering. This is why the wave appears to be continuous and undistorted. Moreover, the wave can