• 대한기계학회논문집A
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• 제23권7호
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• pp.1173-1181
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• 1999

In X-ray stress measurements for uni-directionally deformed surfaces such as grinding, a strongly curved $sin^2{\Psi} diagram, so called $\Psi-splitter, has been observed recently. It has been known that this is caused by the residual shear stress induced in the deformed layer by external forces. In this case it is necessary to consider this enough for ceramics and composite materials with tri-axial stress analysis. However, sufficient studies have not been done about the tri-axial stress analysis of the macro stress and micro. stress on each phase of the composite materials. The result of obtaining is as follows. 1. $\Psi-splitter does not appear in the vertical direction though $\Psi-splitter appears in grinding direction in WC-Co cemented carbides. The reversal of $\Psi-splitter to each phase does not appear. 2. $\Psi-splitter caused in WC-Co cemented carbides has a close relation in dislocation which accumulates in WC phase and phase transformation caused in Co phase. 3. The residual stress on the surface of grinding of each phase is in the state of the compression stress.

• 한국표면공학회지
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• 제54권6호
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• pp.302-306
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• 2021

SnO₂ 30/Ag 15/SnO₂ 30 nm(SAS) tri-layer films were deposited on the glass substrates with RF and DC magnetron sputtering and then electron beam is irradiated on the surface to investigate the effect of electron bombardment on the opto-electrical performance of the films. electron beam irradiated tri-layer films at 1000 eV show a higher figure of merit of 2.72×10^-3 Ω^-1 than the as deposited films due to a high visible light transmittance of 72.1% and a low sheet resistance of 14.0 Ω/☐, respectively. From the observed results, it is concluded that the post-deposition electron irradiated SnO₂ 30/Ag 15/SnO₂ 30 nm tri-layer films can be used as a substitute for conventional transparent conducting oxide films in various opto-electrical applications.

• 한국표면공학회:학술대회논문집
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• 한국표면공학회 2012년도 춘계학술발표회 논문집
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• pp.169-169
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• 2012

Molybdeum oxide-doped 4,4',4"-tris(2-naphthyl(phenyl)amino)tri- phenylamine (2-TNATA) layer 의 도핑농도가 75%일 때 OLED 소자의 성능이 향상되었다. Hole transport layer (HTL) 로 사용된 MOOX-doped 2-TNATA layer는 hole-injection barrier height를 낮추어서 효율적인 홀주입특성을 보였다. 그러나 도핑농도가 75%이하일 때는 소자 특성이 나빠짐을 알 수 있었다.

• Journal of Electrochemical Science and Technology
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• 제12권2호
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• pp.225-229
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• 2021

Commercially available continuous glucose sensors require the operation stability for more than two weeks. Typically, the sensor comprises a sensing layer and an over-coating layer for the stable operation inside the body. In the sensing layer, enzymes and mediators are cross-linked together for the effective sensing of the glucose. The over-coating layer limits the flux of glucose and works as a biocompatible layer to the body fluids. Here, we report the simple preparation of the flux-limiting layer by the condensation of polyethyleneimine (PEI), tri-epoxide linker, and trimethylolpropane triglycidyl ether (PTGE). The sensor is constructed by a layer-by-layer drop-coating of the sensing layer containing glucose dehydrogenase and the PEI-derived blocking layer. It is stable for more than 14 days, which is enough for the sensor in the continuous monitor glucose monitoring (CGM) system.

• 한국자기학회:학술대회 개요집
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• 한국자기학회 2013년도 자성 및 자성재료 국제학술대회
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• pp.116-117
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• 2013

• 한국산학기술학회논문지
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• 제18권1호
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• pp.216-221
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• 2017

폴리머 안경렌즈를 제조할 때 가시광선 영역에서 투과되는 빛을 증가시키고, 안경렌즈 표면에 형성되는 허상을 방지하는 반사방지 기능은 매우 중요하다. 본 연구에서는 굴절률 1.56, 1.60 및 1.67을 갖는 안경렌즈를 폴리머 렌즈 모노머 및 이염화 이부틸 주석 촉매제, 알킬 인산 에스터 이형제 등의 혼합물을 인젝션 몰드 방법으로 열중합 공정을 적용하여 제조하였다. 폴리머 안경렌즈 표면에서의 반사방지 효과를 조사하기 위하여 다층 박막 반사방지 코팅 구조(양면 또는 단면 코팅), 3층 박막의 Gaussian gradient-index profile 불연속 근사 반사방지 코팅 구조, 3층 박막의 quarter-wavelength 근사 반사방지코팅 구조 등 다양한 반사방지 코팅 구조를 설계하였고, E-beam 증착 시스템을 이용하여 열중합공정으로 제조된 폴리머 안경렌즈에 각각 코팅하였다. 폴리머 안경렌즈의 광학적 특성은 UV-visible spectrometer로 분석하였다. 반사방지 코팅 층을 구성하는 박막의 굴절률, 표면 거칠기 등의 소재 특성은 Ellipsometer와 원자힘 현미경(AFM)으로 분석하였다. 분석결과, 굴절률 1.56의 낮은 굴절률을 갖는 폴리머 안경렌즈에서 가장 효과적인 반사방지 코팅 구조는 다층 박막 반사방지 코팅 구조의 양면코팅이었다. 하지만 굴절률 1.67의 고굴절률 안경렌즈에 대해서는 3층 박막의 Gaussian gradient-index profile 불연속 근사반사방지 코팅 구조의 양면 코팅도 다층박막 반사방지 코팅구조의 양면코팅에 상응하는 반사방지 효과를 나타내었다.

• 한국전기전자재료학회논문지
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• 제17권11호
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• pp.1149-1155
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• 2004

In this paper, novel methods for improvement of thermal stability of Ni-germano Silicide were proposed for nano CMOS applications. It was shown that there happened agglomeration and abnormal oxidation in case of Ni-germano Silicide using Ni only structure. Therefore, 4 kinds of tri-layer structure, such as, Ti/Ni/TiN, Ni/Ti/TiN, Co/Ni/TiN and Ni/Co/TiN were proposed utilizing Co and Ti interlayer to improve thermal stability of Ni-germano Silicide. Ti/Ni/TiN structure showed the best improvement of thermal stability and suppression of abnormal oxidation although all kinds of structures showed improvement of sheet resistance. That is, Ti/Ni/TiN structure showed only 11 ohm/sq. in spite of 600 $^{\circ}C$, 30 min post silicidation annealing while Ni-only structure show 42 ohm/sq. Therefore, Ti/Ni/TiN structure is highly promising for nano-scale CMOS technology.

• 한국표면공학회지
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• 제52권3호
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• pp.145-149
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• 2019

Transparent and conductive ZnO/Ag/SnO2 (ZAS) tri-layer films were deposited onto glass substrates at room temperature by using radio frequency (RF) and direct current (DC) magnetron sputtering. The thickness values of the ZnO and $SnO_2$ thin films were kept constant at 50 nm and the value for Ag interlayer was varied as 5, 10, 15, and 20 nm. In the XRD pattern the diffraction peaks were identified as the (002) and (103) planes of ZnO, while the (111), (200), (220), and (311) planes could be attributed to the Ag interlayer. The optical transmittance and electrical resistivity were dependent on the thickness of the Ag interlayer. The ZAS films with a 10 nm thick Ag interlayer exhibited a higher figure of merit than the other ZAS films prepared in this study. From the observed results, a ZAS film with a 10 nm thick Ag interlayer was believed to be an alternative transparent electrode candidate for various opto-electrical devices.

• The Korean Journal of Ecology
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• 제18권2호
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• pp.285-293
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• 1995

The relationships among the contents of Pb, Zn, Cd, Cu and microbial biomass and activity of soil were investigated in Kyongbu, Yongdong, and Chungbu highways. The heavy metal concentrations were the highest in Kyongbu highway with high traffic density. The levels of these metals in soil in three highway sites were much higher than Mt. Kwank as control site. The highest concentrations of heavy metals were found in the upper layer of soil adjacent to the roadside. Dehydrogenase activity (DHA) and adenosine tri-phosphate (ATP) contents were generally lowest at distance of 0.5 m from the roadside. Simple regression analysis indicated that DHA and ATP contents were highly negatively correlated with Pb and Zn concentrations.

• 비파괴검사학회지
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• 제26권2호
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• pp.69-76
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• 2006

차세대 원자로로 부각되고 있는 고온가스로에서는 윈자로에서는 고온 안정성 및 핵분열생성물 차단 성능이 우수한 TRISO(tri-isotropic) 핵연료를 사용하고 있다. TRISO 핵연료 입자는 직경이 약 1mm인 구 형태로 입자의 중심에는 직경 0.5mm의 핵연료 커널(kernel)이 포함되며 커널 외곽을 코팅 층이 에워싸고 있다. 이 코팅 층은 완충(buffer) PyC(pyrolytic carbon)층, 내부 PyC층, SiC층, 그리고 외부 PyC층으로 구성되어 있다. 각 코팅 층의 두께는 수십-백${\mu}m$ 범위이고 사양으로 정해져 있으며, 본 연구에서는 각 코팅 층의 두께를 비파괴적으로 측정하기 위하여 마이크로포커스 X-선 발생장치와 고해상도 X-선 평판(flat panel) 검출기초 구성된 정밀한 X-선 래디오그래피 장치를 개발하였다. 개발된 마이크로 X-선 래디오그래피 장치를 이용하여 $UO_2$ 핵물질 $ZrO_2$를 커널로 사용한 모의 TRISO 핵연료 입사에 대한 투과 영상을 획득한 후 디지털 영상처리 기술을 이용하여 코팅 층 사이의 경계선이 구분 가능하도록 영상을 개선하고 디지털 영상처리 알고리듬을 개발하여 코팅 층의 두께를 파동으로 측정하였다.