http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
GaN-on-Si 기술을 위한 탄화텅스텐 버퍼층의 성장에 관한 연구
조성민,최정훈,최성국,조영지,이석환,장지호,Cho, Sungmin,Choi, Junghoon,Choi, Sungkuk,Cho, Youngji,Lee, Seokhawn,Chang, Jiho 한국전기전자재료학회 2017 전기전자재료학회논문지 Vol.30 No.1
Tungsten carbide (WC) has been suggested as a new buffer layer for the GaN-on-Si technology. We have investigated and optimized the sputtering condition of WC layer on the Si-substrate. We confirmed the suppression of the Si melt-back phenomenon. In addition, surface energy of WC/Si layer was measured to confirm the possibility as a buffer layer for GaN growth. We found that the surface energy(${\gamma}=82.46mJ/cm^2$) of WC layer is very similar to that of sapphire substrate(${\gamma}=82.71mJ/cm^2$). We grow GaN layer on the WC buffer by using gas-source MBE, and confirm that it is available to grow a single crystalline GaN layer.
태양동기-지상반복 궤도를 활용한 군 정찰용 초소형 위성군 설계
조성민,조남석,Cho, Sungmin,Cho, Namsuk 한국군사과학기술학회 2020 한국군사과학기술학회지 Vol.23 No.2
One of the most important steps to consider in utilizing micro-satellites for surveillance or reconnaissance operations is the design of the satellite constellation. The Walker-Delta constellation which is commonly used in designing satellite constellations is not ideal for this operation in which military satellites are required to monitor specific regions continuously in a stable manner. This study aims to discuss the methodology for designing a satellite constellation that is capable of monitoring the fixed region at the fixed time each day by using the Sun synchronous Orbit. The BB(Beach Ball) constellation that we propose outperforms the Walker-Delta constellation in terms of robustness and it holds the merit of being simple in its design, thereby making future expansions more convenient. We expect the BB constellation will have a high applicability as the operational concept of military surveillance satellites is established in the near future.
조성민(Cho Sungmin),김주형(Kim Juhyong),김명모(Kim Myoungmo) 대한토목학회 2007 대한토목학회논문집 C Vol.27 No.3
연약한 점성토 지반에 연직배수재를 설치하고 성토 시공을 진행한 국내 서남해안 연약지반에서 수행한 다양한 지반조사 결과와 현장계측 자료의 분석, 그리고 기존 이론과 수치해석기법 등에 의한 해석을 통해, 성토 재하로 발생하는 연약 점성토 지반의 침하와 횡방향 변형 특성을 정량적으로 규명하였다. 침하량 예측의 경우 Barron의 횡방향 압밀이론과 1차원 유한변형률 압밀이론을 이용하여 예측한 침하량이 실측침하량과 유사하게 나타났으며, 재하 단계별로 지반의 침하와 횡변위간의 관계와 변위속도의 변화 경향을 분석한 결과 소성지수가 증가함에 따라 최대횡변위변화량(ΔY<SUB>max</SUB>)과 침하변위변화량(Δs)의 비가 증가함을 알 수 있었다. 또한, 간극수압 소산곡선을 이용하여 구한 평균압밀도(U<SUB>u</SUB>)보다 침하 곡선을 이용하여 구한 평균압밀도(U<SUB>s</SUB>)가 더 큰 값을 나타냈으며, 실내시험으로 산정한 압밀계수와 현장 압밀계수를 비교한 결과 간극수압을 이용하는 것보다 침하를 이용하여 역산한 압밀계수가 더 큰 값을 나타냈다. Theoretical and numerical analyses on the field data obtained by geotechnical investigations and field instrumentations at several sites where vertical drains were installed in Korea were performed to investigate the deformation characteristics of domestic soft clayey grounds. This study focuses on the quantitative trends of ground displacements, excess pore pressure, and relationship between settlements and lateral displacements. Barron's radial consolidation and 1-dimensional finite strain theory for predicting settlements produced similar results with measured field settlements. The ratio of maximum lateral displacements (Δy<SUB>max</SUB>) to settlements (Δs) increased with increasing plasticity index. Back-calculated average degree of consolidation and coefficient of consolidation using settlements were greater than those using pore pressures.