• 한국신재생에너지학회:학술대회논문집
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• 2007.11a
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• pp.264-267
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• 2007

It is important to reduce optical losses from front surface reflection to improve the efficiency of crystalline silicon solar cells. Surface texturing by isotropic etching with acid solution based on HF and $HNO_3$ is one of the promising methods that can reduce surface reflectance. Anisotropic texturing with alkali solution is not suitable for multicrystalline silicon wafers because of its various grain orientations. In this paper, we textured multicrystalline silicon wafers by simple wet chemical etching using acid solution to reduce front surface reflectance. After that, surface morphology of textured wafer was observed by Scanning Electron Microscope(SEM) and Atomic Force Microscope(AFM), surface reflectance was measured in wavelength from 400nm to 1000nm. We obtained 29.29% surface reflectance by isotropic texturing with acid solution in wavelength from 400nm to 1000nm for fabrication of multicrystalline silicon solar cells.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.04b
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• pp.64-67
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• 2004

본 논문에서는 DNA를 이용한 나노 소자에 응용하기 위하여, photo-lithograpy를 사용하여 나노크기(<100)의 간격을 갖는 금 전극을 제작하였다. 그리고 제작되어진 되어진 나노 전극위에 2-Amino ethanthiol(AET)를 코팅하여 AET와 $\lambda$-DNA 사이의 정전기적 상호 작용을 이용, 금 나노전극 사이에 간단하고 고착율을 높이는 실험을 하였다. SEM(Scanning Electron Microscope) 분석을 통해 나노 크기의 전극 간격을 확인하였고, 두 전극사이에 연결되어진 $\lambda$-DNA는 AFM(Atomic force microscope)을 확인하였다.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.48.1-48.1
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• 2010

Cu has been used for metallic interconnects in ULSI applications because of its lower resistivity according to the scaling down of semiconductor devices. The resistivity of Cu lines will affect the RC delay and will limit signal propagation in integrated circuits. In this study, we investigated the characteristics of electroplated Cu films according to the variation of concentration of organic additives. The plating electrolyte composed of $CuSO_4{\cdot}5H_2O$, $H_2SO_4$ and HCl, was fixed. The sheet resistance was measured with a four-point probe and the material properties were investigated with XRD (X-ray Diffraction), AFM (Atomic Force Microscope), FE-SEM (Field Emission Scanning Electron Microscope) and XPS (X-ray Photoelectron Spectroscopy). From these experimental results, we found that the organic additives play an important role in formation of Cu film with lower resistivity by EPD.

• Proceedings of the Materials Research Society of Korea Conference
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• 2010.05a
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• pp.51.2-51.2
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• 2010

본 연구에서 우리는 casting기법을 통해 생산된 각종 귀금속 제품의 결함 및 강도 향상을 위해 다양한 조건에서 열처리를 실시하였다. casting시 일정하지 못한 온도로 냉각되어 생성된 시료내부의 결함들을 제거하기 위해 진공분위기에서 각 온도 및 시간별 조건을 달리하여 강도 및 grain의 변화를 관찰하였다. 모든 시료는 열처리 후 불안정한 grain 들이 안정화되어 경도 및 강도가 향상되는 경향을 보였으나, 특정 온도 및 시간에서는 오히려 경도가 감소하는 경향을 나타내었다. 열처리 후 모든 시료의 표면특성변화를 관찰하기 위해 OM (Optical microscope), SEM (scanning electron microscope)을 통해 분석하였고, Vickers경도계를 통해 경도 및 강도 변화를 관찰하였다. 또한 XRF(X-ray fluorescence) 분석을 통해 원소별 합금비를 정량적으로 분석하였다. 본 연구 결과를 통해 casting기법으로 생산된 귀금속 제품의 강도, 경도, 표면특성을 향상시킬 수 있는 최적조건을 얻을 수 있었다.

• Journal of the Korean institute of surface engineering
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• v.45 no.6
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• pp.278-283
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• 2012

This investigation evaluated the effect of cavitation condition on electrochemical characteristics of 304 stainless steel, which is widely used for marine environment. The cavitation test with time were conducted on 304 stainless steel in seawater solution. Surface morphologies of specimen were observed by scanning electron microscope (SEM) and 3D microscope. Pitting depth, weight loss and damage rate were analyzed after each cavitation experiment. The surface damage was more severe as the current density increased. A dramatical increase in the damage depth and weight loss was observed after 7 hours of cavitation experiment.

• 정보저장시스템학회:학술대회논문집
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• 2005.10a
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• pp.179-183
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• 2005

Particles in the HDD can cause serious damages such as scratches and thermal asperity(TA) at the head/disk interface(HDI). Accordingly, particles cause data loss including physical and electrical damages. To improve the reliability of head-disk interface, understanding the damage characteristics at the HDI due to particle interactions is required. The materials such as $A1_2O_3$, TiC and aluminum were used in this experiment. The size and hardness of particles injected into the HDI are closely relevant to surface damage caused the data loss on the disk and head. In this paper, a variety of scratches were analyzed using scanning electron microscope(SEM) and atomic force microscope(AFM). In order to analyze defects of very small size on the disk, optical surface analyzer(OSA) was also used.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2014.11a
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• pp.186-186
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• 2014

In this study, corrosion behaviors of Ti-xNb alloys for biomaterials. The Ti-xNb binary alloys contained from 10 wt. % to 50 wt. % contents were manufactured by vacuum arc-melting furnace. Microstructures of the alloys were examined by optical microscope (OM) and field emission scanning electron microscope (FE-SEM). In order to identify the phase constitutents of the Ti-xNb alloys, X-ray diffractometer (XRD) with a Cu K radiation was used. The corrosion behaviors were investigated using potentiostat (Model2273,EG & GCo, USA) in NaCl solution at $(36.6{\pm}1.0)^{\circ}C$.

• Animal cells and systems
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• v.10 no.4
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• pp.219-225
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• 2006

As a result of the faunistic survey of the free-living marine nematodes from coastal algal beds and sublittoral sands in South Korea, we report a meiobenthic species, Desmoscolex cosmopolites Timm, 1970, for the first time from the western Pacific as well as Korean waters. Among 17-ring Desmoscolex species, D. cosmopolites is represented by the following combination of characters: absence of subventral setae on 10th and 14th main rings and the presence of subdorsal setae with large angular lance-shaped tip. A detailed morphological redescription is provided using a scanning electron microscope and a differential interference contrast microscope. Character comparison between D. cosmopolites and its allied congeneric species is also analysed.

• Journal of Welding and Joining
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• v.32 no.2
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• pp.9-13
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• 2014

Friction stir welding (FSW) was successfully performed about 900MPa grade Twinning Induced Plastisity (TWIP) steel. A PCBN tool with convex-type shoulder was applied. Optimal process conditions were deduced. Microstructure and mechanical properties such as hardness, tensile strength and impact absorbed energy were observed and evaluated, respectively. An optical microscope (OM) and a field emission scanning electron microscope (FE-SEM) was selected for observing the grain structure.

• Journal of the Korean institute of surface engineering
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• v.30 no.6
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• pp.365-373
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• 1997

316L and 420 Stainless steels were deposited onto AZ9ID commercial magnesium alloy by plasma spray process with various gas flow rate of, TEX>$H_2$ secondary gas. And hardness as well as were track volume, coefficient of friction also had been measured. wear and hardness were measured by using reciprocal configuration tribometer and microghardness tester, respectively. Also, the microstructure of the coatings surface the cross sectional area of coating surface and cross sectional area of coaing/Substrate interface had been analyzed with Scanning Electron Microscope(SEM) and Optical microscope(OM). Finally, optimal process parameters for the improvement of coating efficiency such as mechanical property and wear behavior were examined.