• Korean Chemical Engineering Research
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• 제44권4호
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• pp.393-398
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• 2006

고농도의 1-부텐을 생산하기 위하여 흡착 분리제의 개발이 필수적인데, 본 연구에서는 메조포러스 실리케이트인 MCM-41을 지지체로 하여 $AgNO_3$를 함침시켜 흡착제를 제조한 후, 1-부텐과 n-부탄의 흡착 특성을 연구하였다. 또한, 열처리 조건에 따른 $Ag^+$ 이온의 형성 비율과 1-부텐의 결합 능력을 알아보았다. MCM-41 흡착제의 경우, 13X 제올라 이트에 비하여 매우 높은 흡착량을 보여주었으며, 은이 담지되었을 때, n-부탄의 흡착량은 감소하는 반면에 1-부텐의 흡착량은 증가함으로써 1-부텐과 n-부탄의 흡착 분리에 매우 좋은 성능을 갖음을 확인할 수 있었다. 또한, 진공 분위기에서 373 K로 열처리한 Ag/MCM-41의 경우 가장 높은 1-부텐/n-부탄 흡착비를 보였으며, 특히 저압에서 매우 높은흡착비를 보여주었다.

• Archives of Pharmacal Research
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• 제26권12호
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• pp.1036-1041
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• 2003

Two chitosanases produced by Aspergillus fumigatus KB-1 were purified by ion exchange and size exclusion chromatographies. Molecular weights of chitosanases were 111.23 kDa (chitosanase I) and 23.38 kDa (chitosanase II). The N-terminal amino acid sequence of chitosanase II was determined as follows: YNLPNNLKQIYDKHKGKXSXVLAKGFTN. The optimum pH of the chitosanase I and II was 6.5 and 5.5, respectively. The optimum temperatures were $60^{\circ}C$ for chitosanase land $70^{\circ}C$ for chitosanase II. Hydrolysis products of two chitosanases were analyzed by HPLC and GPC. Chitosanase I hydrolyzed substrate to glucosamine. Chitosanase II produced chitooligosaccharides.

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.145-148
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• 2011

The thermal behavior of lithiated Si anodes has been investigated using differential scanning calorimetry (DSC). In particular, the effect of Si particle size on the thermal stability of a fully lithiated Si electrode was investigated. For DSC measurements, a lithiated Si anode was heated in a hermetically sealed high-pressure pan with a polyvinylidene fluoride (PVDF) binder and a 1 M $LiPF_6$ solution in an ethylene carbonate (EC)-diethyl carbonate (DEC) mixture. The thermal evolution around $140^{\circ}C$ increases with lithiation and with decreasing particle size; this phenomenon is attributed to the thermal decomposition of the solid electrolyte interface (SEI) film. Exothermic peaks, following a broad peak at around $140^{\circ}C$, shift to a lower temperature with a decrease in particle size, indicating that the thermal stability of the lithiated Si electrode strongly depends on the Si particle size.

• Food Science and Biotechnology
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• 제18권3호
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• pp.667-671
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• 2009

Extract of water-soluble polysaccharide (CFWx), showing inhibiting activity on ${\alpha}-glucosidase$, was prepared from the fruiting bodies of Cordyceps militaris by hot-water extraction, and ethanol precipitation. Chemical characteristics of CFWx were as follows: carbohydrate content 30% including 16% of uronic acid; 51% protein content; monosaccharide composition, Man:Glu:Gal (30:43:27); molecular weight $3-5{\times}10^4$. CFWx was further purified by ion-exchange, gel-permeation, and affinity chromatography and $CFWx-AH-{\alpha}$ fraction was isolated. Fundamental structure of $CFWx-AH-{\alpha}$ was deduced as ${\alpha}-(1{\to}4$)-D-glucan with ${\alpha}-(1{\to}3$)- and/or ${\alpha}-(1{\to}6$)-D-glycosidic side chains based on methylation analysis.

• 한국축산식품학회지
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• 제28권3호
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• pp.301-305
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• 2008

조제분유중의 요오드 및 염소를 신속하고 정확하게 분석하기 위해 이온선택성 전극을 이용한 분석을 실시하였다. 전극을 이용한 측정시 영향을 주는 간섭물질을 제거하기 위해 시료를 용해한 후 3% 아세트산 2 mL를 투입하고, 정제는 filter paper(No.541, Whatman, UK)를 이용하여 여과하는 방법을 선택하였다. 요오드 및 염소이온이 pH에 의해 영향을 받는 것을 확인할 수 있었으며, 0.1 N NaOH를 사용하여 pH를 7.0으로 보정하여 농도를 측정함으로써 요오드와 염소의 회수율 각각 $93.7{\pm}2.7%$와 $103.9{\pm}4.9%$의 결과를 얻을 수 있었다. 간단하고 신속한 간섭물질 제거와 정제를 통해 조제분유중의 요오드 및 염소이온의 농도를 이온전극으로 신속하고 정확하게 측정할 수 있었다.

• 한국자기학회지
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• 제17권4호
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• pp.152-155
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• 2007

다중강전자 상태의 $YMnO_3,\;ScMnO_3$의 전자구조와 자기구조를 국소스핀밀도근사(LSDA)를 이용하여 계산하였다. 강자성 상태이며 강유전 상태의 전자구조는 육방정계 구조로 인하여 Mn 3d 에너지띠가 분리되어 띠틈을 나타내었다. 이러한 에너지 띠틈과 작은 Y, Sc 이온의 반경으로 인하여 $YMnO_3,\;ScMnO_3$는 반강자성 강유전적 성질을 가지는 다중강전자 구조를 가지고 있음을 보았다. 또한 총에너지 계산을 통하여 반강자성, 강유전 상태가 가장 안정됨이 실험과 일치하였다.

• 한국우주과학회:학술대회논문집(한국우주과학회보)
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• 한국우주과학회 2004년도 한국우주과학회보 제13권1호
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• pp.100-100
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• 2004

Silicon Charge Detector is to measure the charge of incident cosmic-ray nuclei with a resolution of 0.2 charge unit for atomic number, Z=1-30 with energy range from 1 to 1000 TeV. It is one of detectors for CREAM (Cosmic Ray Energetics And Mass) experiment to test current models of source and acceleration mechanisms of ultra high energy cosmic rays. It's first flight will be with a NASA zero pressure balloon planned to be launched from McMurdo Station, Antarctica in December 2004. (omitted)

• Transactions on Electrical and Electronic Materials
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• 제1권1호
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• pp.6-11
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• 2000

The hydrogen plasma treatment of silicon wafers in the reactive ion-etching mode was studied for the application to silicon-on-insulator wafers which were prepared using the wafer bonding technique. The chemical reactions of hydrogen plasma with surface were used for both surface activation and removal of surface contaminants. As a result of exposure of silicon wafers to the plasma, an active oxide layer was found on the surface. This layer was rendered hydrophilic. The surface roughness and morphology were examined as functions of the plasma exposing time and power. In addition, the surface became smoother with the shorter plasma exposing time and power. The value of initial surface energy estimated by the crack propagation method was 506 mJ/㎡, which was up to about three times higher as compared to the case of conventional direct using the wet RCA cleaning method.

• 한국진공학회지
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• 제1권1호
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• pp.206-211
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• 1992

SIMOX SOI structures were formed by oxygen ion implantation with a dose of 2 1018 ions/cm2 at 180kev and post-implantation annealing at $1250^{\circ}C$ for 6 hours in nitrogen ambient. The oxygen redistribution process during post-implantation annealing was examined by AES and TEM. The electrical property of the structure was investigated by SRP method. We could find oxygen precipitates in SOI layer was discussed. And the limiting factor to the decrease of the precipitates during post-implantation annealing was discussed also.

• 대한금속재료학회지
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• 제47권6호
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• pp.349-355
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• 2009

In the solvent extraction of Ru(IV) with Alamine336, it was found that Ru took part in the reaction as $RuCl_{6}_^{2-}$ in the HCl concentration range of 1 to 5 M. Interaction parameter between hydrogen ion and $RuCl_{6}_^{2-}$ was estimated by applying Bromley equation to the extraction data. From the mixed solutions of Pd(II) and Ru(IV), the distribution coefficients of Pd were found to be higher than those of Ru in the experimental ranges. Separation factor between Pd and Ru rapidly increased with the decrease of Alamine336 concentration. About 60% of the Ru from the mixed solutions was extracted by TBP at 8.3 M HCl, while Pd was not extracted in the HCl concentration range of 1.6 to 8.3 M.