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전자재료에 응용되는 공정조성 Solders 의 크리프 강도
이성민 대한금속재료학회(대한금속학회) 1994 대한금속·재료학회지 Vol.32 No.8
In view of the importance of Pb-Sn eutectic alloy in soldered interconnection, the creep phenomena in eutectic bulk solders with microstructures similar to the solder joints have been investigated. A variety of loading paths (tensile, fatigue, load relaxation, and creep) along with microstructural examination were employed to characterize constitutieve behavior and identify potential creep mechanisms(e.g. grain boundary sliding) that might have an impact on fatigue. The experimental work was directed as a clearer description of what some of these phenomena might actually be and how they might be related to the underlying creep mechanisms. The mechanisms of grain boundary sliding and creep strengthening in a wavy eutectic alloy were proposed and the creep strength can be explained based on the stabilized subgrain boundaries caused by the two-phase microstructure.
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Tubulin Polymerization에 대한 Podophyllotoxin의 영향
이성민,권기량,임규,황병두 충남대학교 의과대학 지역사회의학연구소 1991 충남의대잡지 Vol.18 No.1
Although the inhibition of microtubule assembly by podophyllotoxin is well established, the mediatory effect of some microtubule associated proteins for inhibition by podophyllotoxin is not clear. The microtubule(MADBP^+) was prepared from rabbit brain through 2 cycles of polymerization-depolymerization and the tubulin without DNA binding protein(MADBP^-) was prepared from MADBP^+ using double strand DNA-cellulose column chromatography and the properties of these tubulin preparation were compared with those of MADBP^+ being sigmoidal and MADBP^- being hyperbolic. MADBP^+ polymerization could he inhibited by podophyllotoxin, whereas MADBP^- polymerization could not. In the various concentration of podophyllotoain, there was little difference in colchicine binding activity between MADBP^- and MADBP^-. In the 2μM concentration of podophyllotoxin, the colchicine binding to MADBP^+ and MADBP^- were competitively inhibited with same extension. From the above results, the possible existence of some proteins which mediates the inhibitory effect of podophyllotoxin for tubulin polymerization was discussed.
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李成民 한국사립대학교 도서관협의회 2002 사대도협회지 Vol.3 No.-
본 연구는 한성대학교 중앙도서관의 구성요소에 대하여 현황을 살펴보고 2004년 재학생 10,000명 시대를 대비하는 장서개발은 주제전문사서제와 자료의 현장구입방식, 인력은 사서배치기준의 50%, 공간은 목적건물로 신축하는 도서관의 공간을 효율적으로 배치하고, 학술정보시스템은 최첨단도서관의 유지발전을 위하여 지속적인 투자 등의 대안을 제시하고자 한다.
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IMT-2000 단말기용 2단 전력증폭기 설계 및 제작
이성민,김창우 경희대학교 레이저공학연구소 2000 레이저공학 Vol.11 No.-
A 2-stage Power Amplifier for IMT-2000 handsets has been developed using InGaAs/AlGaAs/GaAs PHEMT's. The equivalent circuit elements of the Statz-Pucel's nonlinear model of PHEMT's have been extracted by a fitting method. Using the model, the amplifier has been designed through nonlinear simulations with the Libra tool(nonlinear microwave circuit simulator) of HP-EEsof. Based on the circuit scheme obtained from the simulation, the 2-stage power amplifier has been fabricated. To obtain maximum output power, the amplifier has been tuned with ГL=Г(power). The amplifier exhibits 25 dBm output power and 33% power added efficiency with 21 dB linear power gain in 1.92∼1.98GHz band(a uplink frequency band of IMT-2000).
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이성민,허명 이화여자대학교 교과교육연구소 1998 교과교육학연구 Vol.2 No.2
본 연구는 실험실에서 이루어지는 실험 과정 중 중학생들의 태도 평가를 위한 도구를 개발하고, 적용해 봄으로써 간편하면서도 타당도 높은 실험 실습 태도 평가 도구로의 일반화 가능성을 검토하는 데 그 목적이 있다. 연구의 방법은 중학교 1학년 생물 단원 중에서 실험을 선정하고, 선정된 실험의 목표를 진술하고, 그 목표로부터 태도 평가 문항을 추출하였으며 Likert식 평가 도구를 개발하기 위해 평균, 표준편차, 문항-총점 상관계수, 신뢰도를 산출하였다. 그 결과 55개 문항이 선정되었으며, 개발된 도구의 Cronbach alpha 계수는 0.865로 산출되었다. 본 평가 도구를 중학교 1학년 여학생 157명에게 적용하여 얻은 결과는 다음과 같다. 1. 학생들의 태도 정균 점수는 76.0점으로, 학생들의 과학에 대한 태도에 관한 선행 연구에서 얻어진 태도 점수에 비해 높았다. 2. 문항-총점 상관계수의 산출 결과, 실험설 1개~4개 문항을 제외하고는 대부분의 문항들이 문항 변별력이 있는 것으로 나타났다(r>0.02). 3. 평가 문항들은 4개 범주(적극성 , 객관성 , 비판성, 협조성)로 나누어지는데 , 각 범주간에는 유의미한 상관관계는 없는 것으로 나타났다(p>0.05). 4. 학생들의 태도 점수와 과학 성취도 사이에는 유의미한 상관관계가 있었다(p<0.05). 곧 학생들의 과학 성적이 실험실습에서의 학생 태도 점수를 4%-45.7% 정도 설명하여 주었다. A commonly voiced belief among educators is that affective evaluation is as important as cognitive evaluation in science education. But, in school affective evaluation is overlooked for many difficulties. therefore, the purpose of this work was to develop an instrument evaluating middle school students' attitudes in laboratory work. For evaluating students' attitude in laboratory work, the evaluation instrument which is simple and appropriate measure was developed. (1) Materialization of the objectives for experiment (2) Sampling the evaluation items from the experiment objectives (3) The instrument's development and its application To evaluate students' attitude used the Likert-type scales, and its propriety which was calculated by an expert was 83.1%. As a result, 55 statements were composed. This evaluation instrument was applied to the first grader of the middle school(total number of subjects was 157). As results of this work, mean, the standard deviation, the correlation among the items, and the coefficient of correlaton was calculated. The Cronbach alpha coefficient of the evaluation instrument is .865. The following sentences are the results of this work. 1. The students' average points in this work is 76.02. This points are higher than other studies. 2. As a result of the coefficient of correlation, the evaluation items have the sharp distinctions(r>.20). 3. The items split up into 4 categories : enterprising spirit, objectivity, criticism and cooperation. There are no significant correlations among these categories(p>.05). 4. This study showed that there was a significant correlation between the attitudes and students' science achievement(p<.05).
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