• 폴리머
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• 제26권3호
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• pp.335-343
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• 2002

블렌드 (PET/PETG 70/30 블렌드) 수지는 폴리에틸렌테레프탈레이트 (PET)와 폴리에틸렌테레프탈레이트 글리콜 (PETG)을 무게 비 70/30으로 혼합하여, 이축 압출기를 사용하여 제조하였다. 미연신 필름은 이 블렌드와 순수 PETG 수지를 압축성형기로 각각 용융 압축시켜 제조하였고 연신 필름은 미연신 필름을 모세관 레오메타를 사용하여 연신시켜 제조하였다. 제조된 블렌드 연신 필름과 PETG 연신 필름의 결정성, 수축율, 열적, 동역학적 및 기계적 특성을 X-선 회절분석기, 오븐기, DSC, 및 인장시험기를 사용하여 조사하였다. 블렌드와 PETG필름의 결정화도와 밀도는 연신비와 연신 속도의 증가와 더불어 증가하였으나 반면 연신 온도 증가와 더불어 감소하였다 또한 블렌드 필름의 결정화도와 밀도는 PETG 필름보다 높게 나타났다. 두 필름의 인장강도와 인장탄성률은 연신비 및 연신 속도 증가와 더불어 증가하였고 연신온도 증가에 따라 감소하였다. 또한 블렌드 필름의 인장강도와 인장탄성률이 PETG 필름 보다 높게 나타났다. 두 필름의 수축율은 연신비와 연신 속도가 증가할수록 감소하였고 미연신 블렌드 필름의 수축율이 순수 PET 필름보다 600% 증가함을 보였다.

• Transactions on Electrical and Electronic Materials
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• 제14권3호
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• pp.133-138
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• 2013

Acrylonitrile-butadiene-styrene (ABS) plastic is a polymer material extensively used in electrical and electronic applications. Nickel (Ni) thin film was deposited on ABS by electroless plating, after its surface was treated and modified with atmospheric plasma generated by means of dielectric barrier discharges (DBDs) in air. The method in this study was developed as a pre-treatment for electroless plating using DBDs, and is a dry process featuring fewer processing steps and more environmentally friendliness than the chemical method. After ABS surfaces were modified, surface morphologies were observed using a scanning electron microscope (SEM) to check for any physical changes of the surfaces. Cross-sectional SEM images were taken to observe the binding characteristics between metallic films and ABS after metal plating. According to the SEM images, the depths of ABS by plasma are shallow compared to those modified by chemically treatment. The static contact angles were measured with deionized (DI) water droplets on the modified surfaces in order to observe for any changes in chemical activities and wettability. The surfaces modified by plasma showed smaller contact angles, and their modified states lasted longer than those modified by chemical etching. Adhesion strengths were measured using 3M tape (3M 810D standard) and by 90° peel-off tests. The peel-off test revealed the stronger adhesion of the Ni films on the plasma-modified surfaces than on the chemically modified surfaces. Thermal shock test was performed by changing the temperature drastically to see if any detachment of Ni film from ABS would occur due to the differences in thermal expansion coefficients between them. Only for the plasma-treated samples showed no separation of the Ni films from the ABS surfaces in tests. The adhesion strengths of metallic films on the ABS processed by the method developed in this study are better than those of the chemically processed films.

• 한국진공학회지
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• 제20권1호
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• pp.63-69
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• 2011

본 연구에서는 기존 실리콘 반도체 기술 기반의 포토 및 이빔 리소그래피 공정을 통하여 유기 반도체 소자를 패터닝하였다. P3HT나 PEDOT 등의 유기 반도체는 용매에 녹기 때문에 MIMIC (micro-molding in capillaries)이나 inkjet printing 기술을 이용하여 마이크로미터 크기의 소자 제작이 가능하였으나, 펜타신은 용매에 녹지 않기 때문에 매우 복잡한 방법으로 마이크로미터 크기의 소자를 제작하여왔다. 그러나, 본 연구에서는 원자층 증착 방법으로 증착한 산화 알루미늄막을 펜타신의 보호층으로 이용하여 기존의 포토 및 이빔 리소그래피 방법으로 마이크로미터크기의 펜타신 소자를 제작하였으며 그 전기 특성을 확인하였다.

• Advances in nano research
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• 제5권3호
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• pp.193-201
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• 2017

ZnO, ZnO: Cu, Ga, and ZnO: Cu, Ga, Ag thin films were obtained by oxidization of ZnS and ZnS: Cu, Ga films deposited onto glass substrates by electron-beam evaporation from ZnS and ZnS: Cu, Ga targets and from ZnS: Cu, Ga film additionally doped with Ag by the closed space sublimation technique at atmospheric pressure. The film thickness was about $1{\mu}m$. The oxidation was carried out at $600-650^{\circ}C$ in air or in an atmosphere containing water vapor. Structural characteristics were investigated by X-ray diffraction (XRD) and atomic force microscopy (AFM). Photoluminescence (PL) spectra of the films were measured at 30-300 K using the excitation wavelengths of 337, 405 and 457.9 nm. As-deposited ZnS and ZnS: Cu, Ga films had cubic structure. The oxidation of the doped films in air or in water vapors led to complete ZnO phase transition. XRD and AFM studies showed that the grain sizes of oxidized films at wet annealing were larger than of the films after dry annealing. As-deposited doped and undoped ZnS thin films did not emit PL. Shape and intensity of the PL emission depended on doping and oxidation conditions. Emission intensity of the films annealed in water vapors was higher than of the films annealed in the air. PL of ZnO: Cu, Ga films excited by 337 nm wavelength exhibits UV (380 nm) and green emission (500 nm). PL spectra at 300 and 30 K excited by 457.9 and 405 nm wavelengths consisted of two bands - the green band at 500 nm and the red band at 650 nm. Location and intensities ratio depended on the preparation conditions.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.1038-1041
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• 2003

In the paper, we investigated silicon surface microstructures formed by reactive ion etching in hollow cathode system. Wet anisotropic chemical etching technique use to form random pyramidal structure on <100> silicon wafers usually is not effective in texturing of low-cost multicrystalline silicon wafers because of random orientation nature, but High density hollow cathode plasma system illustrates high deposition rate, better film crystal structure, improved etching characteristics. The etched silicon surface is covered by columnar microstructures with diameters form 50 to 100nm and depth of about 500nm. We used $SF_{6}$ and $O_{2}$ gases in HCP dry etch process. This paper demonstrates very high plasma density of $2{\times}10^{12}$ $cm^{-3}$ at a discharge current of 20 mA. Silicon etch rate of 1.3 ${\mu}s/min$. was achieved with $SF_{6}/O_{2}$ plasma conditions of total gas pressure=50 mTorr, gas flow rate=40 sccm, and rf power=200 W. Our experimental results can be used in various display systems such as thin film growth and etching for TFT-LCDs, emitter tip formations for FEDs, and bright plasma discharge for PDP applications. In this paper we directed our study to the silicon etching properties such as high etching rate, large area uniformity, low power with the high density plasma.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2008년도 추계학술대회 논문집 Vol.21
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• pp.259-259
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• 2008

The LTCC (Low Temperature Co-fired Ceramic) technology meets the requirements for high quality microelectronic devices and microsystems application due to a very good electrical and mechanical properties, high reliability and stability as well as possibility of making integrated three dimensional microstructures. The wet process, which has been applied to the etching of the metallic thin film on the ceramic substrate, has multi process steps such as lithography and development and uses very toxic chemicals arising the environmental problems. The other side, Plasma technology like ion beam sputtering is clean process including surface cleaning and treatment, sputtering and etching of semiconductor devices, and environmental cleanup. In this study, metallic multilayer pattern was fabricated by the ion beam etching of Ti/Pd/Cu without the lithography. In the experiment, Alumina and LTCC were used as the substrate and Ti/Pd/Cu metallic multilayer was deposited by the DC-magnetron sputtering system. After the formation of Cu/Ni/Au multilayer pattern made by the photolithography and electroplating process, the Ti/Pd/Cu multilayer was dry-etched by using the low energy-high current ion-beam etching process. Because the electroplated Au layer was the masking barrier of the etching of Ti/Pd/Cu multilayer, the additional lithography was not necessary for the etching process. Xenon ion beam which having the high sputtering yield was irradiated and was used with various ion energy and current. The metallic pattern after the etching was optically examined and analyzed. The rate and phenomenon of the etching on each metallic layer were investigated with the diverse process condition such as ion-beam acceleration energy, current density, and etching time.

• 대한기계학회논문집B
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• 제41권1호
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• pp.21-28
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• 2017

물의 증발에 따른 냉각 효과를 이용하는 증발냉각방식은 기존 증기 압축식 방식에 비하여 냉방에 소요되는 에너지를 현저히 감소시킬 수 있고 CFC 냉매를 사용하지 않아 친환경적이다. 본 연구에서는 습채널의 물 퍼짐성이 개선된 플라스틱/종이 재질로 크기 $300mm{\times}300mm{\times}300mm$, 채널 핏치 $5mm{\times}5mm$, $5mm{\times}7mm$, $7mm{\times}7mm$의 직교류 간접증발소자를 제작하고 간접증발효율 및 압력 손실을 측정하였다. 간접증발효율은 채널 핏치가 가장 작은 $5mm{\times}5mm$ 소자의 가장 크게 나타났다. 이는 작은 $5mm{\times}5mm$ 소자의 전열 면적이 가장 크기 때문이다. 또한 간접증발소자 설치로 인해 절약되는 에너지도 $5mm{\times}5mm$ 소자에서 가장 크게 나타났다. 한편 습채널의 압력 손실은 건채널의 값보다 크게 나타났다. 이론 해석 모델은 간접증발효율과 압력손실을 과소 예측하였다.

• Progress in Superconductivity
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• 제7권1호
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• pp.58-63
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• 2005

We investigated the surface oxidation behavior of cube-textured polycrystalline nickel at various oxidation conditions. Cube-textured NiO film was formed on a cube-textured polycrystalline nickel regardless of oxidation conditions but different growth behavior of NiO crystals was observed depending on the oxidation conditions. The introduction of water vapor into $O_2$ did not affect the texture evolution, but rough and porous microstructure was developed. Microstructure of NiO film tends to be denser as the oxygen partial pressure increases. It is interesting that (111) peak of theta - two theta diffraction pattern started to get stronger in air atmosphere and (111) plane became the major texture in the substrate oxidized in high purity argon gas. Small amount of high index crystallographic plane NiO peak crystal was observed when $N_{2}O$ was used as an oxidant while only (200) plane crystal was formed in dry $O_2$ atmosphere. Flat and smooth surface was changed into rough faceted one when ramping rate to oxidation temperature was faster. The grain size of NiO was decreased when the oxygen partial pressure was low. It was also observed that the modification of nickel surface suppressed the development of (200) texture.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2004년도 춘계학술대회 논문집 반도체 재료 센서 박막재료 전자세라믹스
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• pp.5-8
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• 2004

전자빔 증착법 (e-beam evaporation)를 이용하여 $TiO_2$ 박막과 $Al_2O_3/TiO_2$ 이중박막을 제조한 후, $800^{\circ}C$ 공기 중에서 열처리하여, 알루미나 층의 유무에 따른 두 박막의 전기전도 특성과 100 ppm CO 가스에 대한 반응 특성을 고찰하였다. 알루미나 층이 증착되지 않은 순수한 $TiO_2$ 박막의 전기 전도도 (in dry air)는 $100^{\circ}C-500^{\circ}C$ 온도범위에서 온도가 증가함에 따라 증가하였으며 알루미나 층이 증착된 $Al_2O_3/TiO_2$ 이중막보다 높은 전도도를 나타내고 있으나, 약 $300^{\circ}C$이상의 온도에서는 $Al_2O_3/TiO_2$ 이중막의 전기 전도도가 급격히 증가하여 $TiO_2$ 박막의 전기전도도 보다 더 높은 값을 나타내었다. 또한 온도에 따른 CO 가스 감도(sensitivity)는 $TiO_2$ 박막의 경우 $400^{\circ}C$까지는 서서히 증가하여 그 이상의 온도에서 급격히 감소하였으나, $Al_2O_3/TiO_2$ 이중막은 $250^{\circ}C$에서 감도가 급격히 증가하여 최대값을 나타내었으며, $350^{\circ}C$에서 감도가 급격히 감소하는 특성을 나타내었다.

• 한국구조물진단유지관리공학회 논문집
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• 제21권1호
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• pp.83-90
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• 2017

NaCl과 $LiNO_2$의 첨가량에 따른 콘크리트에 매립된 철근의 부식거동을 전기화학적 임피던스 분광법을 이용하여 고찰하였다. 부식가속 방법중 하나인 건습반복법을 이용하여 단기간 내에 부식현상을 촉진하였으며, 측정된 임피던스 값을 통해 등가회로를 제안할 수 있었다. NaCl $1.2kg/m^3$이 첨가된 콘크리트에 매립된 철근의 부동태 피막이 빠르게 파괴되는 것을 확인할 수 있었으며, 염화물 첨가량 대비 0.6M의 $LiNO_2$를 첨가한 경우 부식진행속도가 크게 저하하는 것을 확인할 수 있었다. 또한 염화물 첨가량 대비 1.2M의 $LiNO_2$를 첨가한 경우 부동태 피막이 부식가속시간이 지나도 파괴되지 않고 성능이 유지되는 것을 확인할 수 있었다.