• BMB Reports
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• v.31 no.2
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• pp.170-176
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• 1998

Phosphatidylethanolamine N-methyltransferase (PEMT) is known to be a membrane-associated protein. However, cytosolic PEMT was detected when sufficient amounts of exogenous phospholipids were added in the incubation media. The methylation of phospholipids was measured by the incorporation of the $[^3H]-methyl$ group from S-adenosylmethionine and the methylated phospholipids were analyzed by thinlayer chromatography. The essence of the assay condition for the cytosolic enzyme was the inclusion of 200 ${\mu}g$ of each substrate, phosphatidylethanolamine (PE), phosphatidyl N-monomethylethanolamine (PME) and phosphatidyl N,N-dimethylethanolamine (PDE), in the reaction mixture of 100 ${\mu}l$. The subcellular fractionation of brain PEMT activities revealed that approximately 38.1 % for PME, 39.5% for PDE, and 22.4% for PC formation was present in the cytosolic fraction. The general properties of cytosolic PEMT were characterized and compared with those of neuronal nuclei PEMT.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.05a
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• pp.471-472
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• 2006

High aspect ratio of nano hairs on a plastic substrate is molded using thermoplstic materials including COC, PP, PC and PMMA. As a template for molding nano hairs, AAO membrane is adopted, which is 60um thick and 13mm in diameter. This membrane has about 109 of through-holes of which diameter is around 200nm. This AAO membrane and the pellet of materials are stacked in the mold and pressed to mold after heating up to be melted. The AAO membrane is removed using KOH to obtain the molded nano hairs. As a result, the diameter of the molded hairs is around 200nm and the length is $2um{\sim}60um$ depending on the molding conditions and materials.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.65.1-65.1
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• 2011

결정질 실리콘 웨이퍼의 전면 재결합 속도, 비저항은 태양전지 특성에 영향을 끼치는 중요한 요소이다. 태양전지의 최종목표인 효율에 미치는 영향을 알아보기 위해 패시베이션 처리된 n-형 웨이퍼를 사용한 태양전지에서 웨이퍼의 비저항과 전면 재결합 속도를 조절하였고 그에 따른 변환 효율과 기본 파라미터 값의 변화를 확인하였다. PC1D를 사용하여 시뮬레이션을 수행하였으며 이론적으로 비저항 = $0.06557{\Omega}{\cdot}cm$, 전면 재결합 속도 = 100cm/s에서 18.46%의 효율을 얻을 수 있었다.

• Corrosion Science and Technology
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• v.8 no.6
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• pp.227-231
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• 2009

Mg and Mg alloys have been used for lots of applications, including automobile industry, aerospace, mobile phone and computer parts owing to low density. However, Mg and Mg alloys have a restricted application because of poor corrosion properties. Thus, improved surface treatments are required to produce protective films that protect the substrate from corrosive environments. Environmental friendly Plasma Electrolytic Oxidation (PEO) has been widely investigated on magnesium alloys. PEO process combines electrochemical oxidation with plasma treatment in the aqueous solution. In this study, AZ91 Mg alloys were treated by PEO process in controlling the current with PC condition and treated time, concentration of NaF, NaOH, and $Na_2SiO_3$. The surface morphology and phase composition were analyzed using SEM, EDS and XRD. The potentiodynamic polarization tests were carried out for the analysis of corrosion properties of specimen. Additionally, salt spray tests were carried out to examine and compare the corrosion properties of the PEO treated Mg alloys.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2003.11a
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• pp.494-497
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• 2003

We report the dark spots in organic light emitting diodes by using a near-field scanning microwave microscope. Devices structure was glass / indium-tin-oxide(ITO) / copper-pthalocyiane(Cu-Pc) / tris-(8-hydroquinoline)aluminum(Alq3) / aluminum(Al). We made artificial dark spots by using a etching technique on a ITO substrate. Near-field scanning microwave microscope images and reflective coefficient of dark spots were measured and compared by the change of various applied voltage changes 0-15V.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2004.07a
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• pp.349-352
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• 2004

The $CdS_{1-x}Se_x$ thin films were grown on the GaAs(100) wafers by a Hot Wall Epitaxy method(HWE). The temperatures the source and the substrate temperature are $580^{\circ}C\;and\;440^{\circ}C$ respectively. The crystalline structure of thin films was investigated by double crystal X-tay diffraction(DCXD). Hall effect on the sample was measured by the van der Pauw method and studied on the carrier density and mobility dependence on temperature. In order to explore the applicability as a photoconductive cell, we measured the sensitivity($\gamma$), the ratio of photocurrent to darkcurrent(pc/dc), maximum allowable power dissipation(MAPD), spectral response and response time.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.145-146
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• 2005

Cadmium sulphide (CdS) films have been prepared on polycarbonate (PC), polyethylene terephthalate (PET), and Coming 7059 substrates by r.f. magnetron sputtering technique at room temperature. A comparison of the properties of the films deposited on polymer and glass substrates was performed. In addition, the effect of the sputter pressure on the structural and optical properties of these films was evaluated.

• Journal of the Korean Crystal Growth and Crystal Technology
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• v.6 no.3
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• pp.341-350
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• 1996

The CdS thin films are grown on quartz plate by hot wall epitaxy. The source and substrate temperature is $590^{\circ}C$ and $400^{\circ}C$ respectively, and thickness of the film is $2.5\;\mu\textrm{m}$. Using extrapolation method of X-ray diffraction patterns for the CdS thin film, it was found hexagonal structure whose lattice constant a and c were $4.137\;{\AA}$ and $6.713\;{\AA}$, respectively. Hall effect on this sample was measured by the method of van der Pauw and studied on cattirer density and mobility depending on temperature. From hall data, the mobility was likely to be decreased by piezoelectric scattering in the temperature range 30 K to 200 K and by polar optical scattering in the temperature range 200 K to 293 K. In order to explore the applicability as a photoconductive cell we measured the sensitivity ($\gamma$), the ratio of photocurrent to darkcurrent (pc/dc), maximum allowable power dissipation (MAPD), spectral response and response time. The results indicated that for the samples annealed in Cu vapor the photoconductive characteristics are the best. Then we obtained the sensitivity of 0.99, the value of pc/dc of $9.42{\times}10^{6}$, the MAPD of 318 mW, and the rise and decay time of 10 ms and 9 ms, respectively.

• Journal of fish pathology
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• v.21 no.1
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• pp.1-11
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• 2008

We report the existence of new type of phosphatidylcholine-hydrolyzing phospholipase D (PLD), which has been characterized and partially purified in the scuticociliate, Uronema marinum. The enzyme from partial purification showed that it was existed in membrane fraction and was a neutral PLD, which catalyzed both transphosphatidylation and hydrolysis reaction. The activity of partially purified membrane-bound PLD was also found to be optimal at pH 7.0-7.5 for 2 hours at 37℃ and depended strictly on the presence of Ca2+ (2.5 mM) and Mg2+ (1.6 mM). Immunoblot analysis indicated that the enzyme was distinct from hPLD1 (human PLD1) and hPLD2 (human PLD2) because it was not recognized by a polyclonal antibody raised to the 12 terminal amino acid of these enzymes. We also found that the membrane-bound PLD is a PIP2-dependent PLD and that GTP-binding proteins are not implicated in the regulation of this enzyme: This enzyme activity is markedly stimulated by phosphatidylinositol 4,5-bisphosphate (PIP2) but not by the small G-protein Arf and GTPrS. In addition, this enzyme was capable of hydrolyzing phosphatidylcholine (PC) but not phosphatidylethanolamine (PE), implying that PC was a preferred substrate.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.377-377
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• 2011

Organic solar cells (OSCs) with low cost have been studied to apply on flexible substrate by solution process in low temperature [1]. In previous researches, conventional organic solar cell was composed of metal oxide anode, buffer layer such as PEDOT:PSS, photoactive layer, and metal cathode with low work function. In this structure, indium tin oxide (ITO) and Al was generally used as metal oxide anode and metal cathode, respectively. However, they showed poor reliability, because PEDOT:PSS was sensitive to moisture and air, and the low work function metal cathode was easily oxidized to air, resulting in decreased efficiency in half per day [2]. Inverted organic solar cells (IOSCs) using high work function metal and buffer layer replacing the PEDOT:PSS have focused as a solution in conventional organic solar cell. On the contrary to conventional OSCs, ZnO and TiO2 are required to be used as a buffer layer, since the ITO in IOSC is used as cathode to collect electrons and block holes. The ZnO is expected to be excellent electron transport layer (ETL), because the ZnO has the advantages of high electron mobility, stability in air, easy fabrication at room temperature, and UV absorption. In this study, the IOSCs based on poly [N-900-hepta-decanyl-2,7-carbazole-alt-5,5-(40,70-di-2-thienyl-20,10,30-benzothiadiazole)] (PCDTBT) : [6,6]-phenyl C71 butyric acid methyl ester (PC70BM) were fabricated with the ZnO electron-transport layer and MoO3 hole-transport layer. Thickness of the ZnO for electron-transport layer was controlled by rotation speed in spin-coating. The PCDTBT and PC70BM were mixed with a ratio of 1:2 as an active layer. As a result, the highest efficiency of 2.53% was achieved.