• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.10b
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• pp.167-168
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• 2002

In this study, the effects of oxide layer formed on the wear tracks of TiN coated silicon wafer on friction characteristics were investigated. Silicon wafer was used for the substrate of coated disk specimens, which were prepared by depositing TiN coating with $1\;{\mu}m$ in coating thickness. AISI 52100 steel balls were used for the counterpart. The tests were performed both in air for forming oxide layer on the wear track and in nitrogen to avoid oxidation. This paper reports characterization of the oxide layer effects on friction characteristics using X-ray diffraction (XRD). scanning electron microscopy (SEM) and friction force microscope (FFM).

• 한국신재생에너지학회:학술대회논문집
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• 2010.11a
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• pp.41.1-41.1
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• 2010

전기수력학적 분무를 이용한 액적 미립화 기술은 나노사이즈의 액적 형성, 쿨롱 반발력에 의한 균일한 액적 형성, 그리고 향상된 액적 타겟팅을 가능하게 한다. 따라서 이를 이용하여 매우 균일한 박막 코팅이 가능하다. 이러한 점에 힘입어 현재 진공 공정으로 제작되고 있는 CIGS태양전지의 광흡수층을 비진공 공정중 하나인 전기수력학적 미립화를 이용하여 실험하였다. Ethanol-based 의 CIGS나노 입자를 포함하는 콜로이드 상태의 전구체를 이용하여 적절히 가열된 몰리브덴 배면 전극위에 적용하였다. 미립화한 액적은 접지된 몰리브덴 층에 부착되는 즉시 증발하여 CIGS입자를 남긴다. 여기서 가장 중요하게 다루어야 할 조건은 기판의 온도, 인가 전압, 전구체의 유량이다. 분사 모드는 Cone-jet을 적용하였으며 5~15kV의 인가 전압에서 1ml/hr내외의 유량을 공급하여 3분 이내에 적절한 광흡수층 두께인 1마이크론 내외에 도달할 수 있다. 이와같은 조건으로 형성된 박막층에 관한 SEM image를 통해 다른 비진공 코팅 방식과 비교하였다.

• ETRI Journal
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• v.25 no.6
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• pp.517-522
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• 2003

This investigation confirms that silver stearate consists of an infinite-sheet, two-dimensional, nonmolecular layered structure. Scanning electron microscopy, X-ray diffraction, and infrared spectroscopy reveal the following: plate-like morphology is identified from the SEM image, XRD peaks can be indexed to the (0k0) reflections of a layered structure, and infrared peaks show that alkyl chains are present in an all-trans conformational state with little or no significant gauche population. Based on these structural characteristics, we demonstrate that silver stearate, a prototype of layered organic-inorganic hybrid material, can be grown not only in a designed two-dimensional pattern but also in three-dimensionally ordered ways by using carboxyl-group terminated nanoparticles as a template.

• Proceedings of the Korean Vacuum Society Conference
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• 2015.08a
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• pp.239.2-239.2
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• 2015

Graphene is a most interesting material due to its unique and outstanding properties. However, semi-metallic properties of graphene along with zero bandgap energy structure limit further application to optoelectronic devices. Recently, many researchers have shown that band gap can be induced in the Bernal stacked bilayer graphene. Several methods have been used for the controlled growth of the Bernal staked bilayer graphene, but it is still challenging to control the growth process. In this paper, we synthesize the large area Bernal stacked bilayer graphene using multi heating zone low pressure chemical vapor deposition (LPCVD). The synthesized bilayer graphenes are characterized by Raman spectroscopy, optical microscope (OM), scanning electron microscopy (SEM). High resolution transmission electron microscopy (HRTEM) is used for the observation of atomic resolution image of the graphene layers.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2002.05b
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• pp.103-106
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• 2002

The applicability of models based on fractal morphology to characterize $(Ba\;Sr)TiO_{3}$ thin film surfaces was investigated. The fractal morphology of coated barium strontium titan oxide thin film surfaces was described using fractal dimension from scanning electro microscopy image. The $(Ba\;Sr)TiO_{3}$ coating were deposited on silicon wafers using $(Ba\;Sr)TiO_{3}$ solution and spin coater. BST solution was composited by mol ratio, and then spin-coated from 3 times to 5 times coating on $Pt/SiO_{2}/Si$ substrate. Qualitative thin film analysis was performed with scanning electro microscopy (SEM), and surfaces parameters such as average grain diameter, roughness exponent and fractal dimension were determined.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.466-471
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• 2004

In focused-ion-beam (FIB) application of micromachining and device transplantation, four kinds of FIB processes, namely FIB sputtering, FIB-induced etching, redeposition, and FIB-induced deposition, are well utilized. As with FIB systems, scanning electron microscopes(SEMs) were extensively used in the semiconductor industry. They are the tools of choice for defect review and providing the image resolution needed for process monitoring. The enhanced capabilities of a dual-column on one chamber system are quickly becoming realized by the nano industry for performing a wide range of application.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2002.05a
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• pp.310-316
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• 2002

In this study, the effects of oxide layer formed on the wear tracks of TiN coated silicon wafer on friction and wear characteristics were investigated. Silicon wafer was used for the substrate of coated disk specimens, which were prepared by depositing TiN coating with $1{\mu}m$ in coating thickness. AISI 52100 steel ball was used for the counterpart. The tests were performed both in air for forming oxide layer on the wear track and in nitrogen to avoid oxidation. This paper reports characterization of the oxide layer effects on friction and wear characteristics using X-ray diffraction (XRD). Auger electron spectroscopy (AES), scanning electron microscopy (SEM) and sliding tests.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2004.10a
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• pp.921-924
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• 2004

This paper is to investigate a crack for plasma sprayed MCrAlY coated material by acoustic emission method in 4-point bending test. The CoNiCrAlY is coated on Inconel-718 by vacuum plasma spray process. Micro-hardness measurement was conducted by means of Micro Vickers-hardness indentor. The porosity of coating layer was measured using a SEM and Image Analyzer. AE monitoring system is composed of PICO type sensor, a wide band preamplifier(40dB), a PC and AE DSP(16/32 PAC) board. The AE count, Hit and energy of coating specimens is measured according to coating thickness.

• Journal of Korea Technical Association of The Pulp and Paper Industry
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• v.32 no.2
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• pp.35-39
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• 2000

Refining is very important process of fibers treatment for proper paper properties. An extent of refining is usually measured by freeness, although freeness gives complicated meanings. One of a direct way of studying the refining effects on pulp fibers is making photomicrographs of beaten fibers. The conventional microscopy like light microscopy(LM) and scanning electron microscopy(SEM) require to preserve the wet structure of pulp fibers morphologically since most of papermaking process is carried out almost entirely in water. Recently developed microscopy, especially confocal laser scanning microscopy(CLSM), offers the possibility of examining fully hydrated pulp fibers. Cross-sectional images of wet pulp fibers are also generated using optical sectioning by CLSM and image analysis in order to verify and quantify the extent of fiber wall swelling indicating the internal fibrillation. At low beating load such as 2.5 kgf, in the same freeness, breaking length is higher than that of high beating load such as 5.6 kgf. fiber wall thickness at low beating load is greater than that at high beating load. This result is accounted for the fact that internal fibrillation in the low beating load was high.

• Structural Engineering and Mechanics
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• v.15 no.3
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• pp.367-378
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• 2003

The magnitude of the plastic zone around the crack tip of DENT (Double Edge Notched Tension) specimen and the crack growth length under cyclic loading were measured by ESPI (Electronic Speckle Pattern Interferometry) system. The measured magnitude of plastic zone was compared with the proposed by Irwin and calculated by a nonlinear static method of MSC/NASTRAN. The measured crack growth length by ESPI system was also compared with the obtained data by the image analysis system. From the study, it is confirmed that the plastic zone and crack growth length can be measured accurately with the high-tech equipment (ESPI System).