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보강재에 도금된 Cu층이 Al/SiC복합재료의 젖음성에 미치는 영향
이경구,조규종,이도재,Lee, Gyeong-Gu,Jo, Gyu-Jong,Lee, Do-Jae 한국재료학회 2001 한국재료학회지 Vol.11 No.5
SiC 보강재 표면에 도금된 Cu금속층이 Al/SiC복합재료의 젖음성에 미치는 영향을 검토하였다. 보강재에 대한 금속층의 도금은 무전해도금법을 이용하였으며, Al/SiC 복합재료의 제조는 텅스텐 발열체 진공로의$ 670^{\circ}C$~$900^{\circ}C$에서 제조하여 보강재와 기지간의 접촉부위를 촬영하여 젖음성을 측정하였다 젖음성 측정 결과 보강재에 도금된 Cu층은 젖음성을 향상시켰고, 젖음성의 개선은 보강재에 도금된 금속층과 기지간의 반응에 의해 계면에너지를 변화시킴으로서 나타난 결과이며. 반응을 통한 산화피막의 배제도 영향을 미친 것으로 판단된다 Effects of coating treatment of metallic Cu film on SiC for Al/SiC composite were studied. The Copper was deposited on SiC by electroless plating method. Al/sic composite was fabricated at temperature range of $670^{\circ}C$ to 90$0^{\circ}C$ under vacuum atmosphere. The wetting behavior of Al/SiC composite were analysed by SEM and XRD. The coating treatment on SiC improved wettability of Al melt on SiC considerably comparing to the non coated SiC. This improved wettability seems strongly concerned to the increase of chemical reactivity between coated layer and Al matrix. The improvement of wettability of Al melt on the Cu coated SiC was closely related to in the initial stage of reaction. The metallic film played an important role in reducing the interfacial free energy and breaking down the aluminum oxide film through the reaction with Al melt. The wetting behavior of the as-received SiC with Al melt was not uniform, indicated by the contact angles from less than $97^{\circ}$to more than $97^{\circ}$.
한국과 중국, 대만, 일본의 전통약 임상시험 현황에 대한 연구
이경구,배순희,신현규,Lee, Kyun-Goo,Bae, Sun-Hee,Shin, Hyeon-Kyoo 한국한의학연구원 2006 한국한의학연구원논문집 Vol.12 No.1
Background and Aims: Herbal drugs and traditional medicines have lately attracted considerable attention by global pharmaceutical corporations because the conventional chemical drugs didn't work well for many chronic diseases or intractable diseases. The government of Korea is also supporting to develop the new drug which is high value added product, and the natural medicine including herbal medicine(or Traditional Korean Medicine) have a significant presence in this field. non-clinical pharmacology/toxicology study and clinical trial are the two major criteria which estimate efficacy and safety for registration of new drugs. All of the pharmaceutical companies producing herbal medicine and the academic and the academic world of Tradition Korean Medicine have the will to develop new herbal drugs, but there are obstacles that they have neither experience nor guideline about clinical trial. Therefore for developing new herbal drugs, it is necessary to research the present conditions and comprehensive systems about clinical trial in Northeast Asian countries China, Taiwan and Japan because they have the common background with Korea in traditional medicine fields. Methods : The present state of clinical trial for herbal medicine in Korea was investigated. And then, those in China, Taiwan, Japan was also investigated. Results and conclusions : There are significant differences among 4 Southeast Asian countries Korea, China, Taiwan and Japan each in present condition, purpose, involved comprehensive system including legislation, and actual operation of clinical trial for traditional medicine.
이경구,김태진,김은석,김진구 대한건축학회 2007 大韓建築學會論文集 : 構造系 Vol.23 No.7
Many buildings throughout the world have experienced severe damage due to blast during past several decades. Local failure of a primary structural component induced by direct air-blast loading may be itself a critical damage and lead to the partial or full collapse of the building. This paper presents behavior of H-section steel columns under a blast loading, such as bomb attack, using a computational fluid dynamic nonlinear finite element analytical approach. Parametric studies have been conducted to observe the effect of column section shape on blast pressure, local damage of weak or strong-axis section column against blast wave, and the effect of blast wave reflected by ground on pressure on a column. This study shows that the analytical approach is reasonable and effective to understand the nature of blast wave and complex interaction between blast loading and steel column behavior.