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RTCVD 법으로 성장한 Si1-xGex 에피막의 특성
정욱진,군영규,배영호,김광일,강봉구,손병기 ( W . J . Chung,Y . K . Kwon,Y . H . Bae,K . I . Kim,B . K . Kang,B . k. Sohn ) 한국센서학회 1996 센서학회지 Vol.5 No.2
The growth and characterization of heteroepitaxial Si_(l-x)Ge_x films grown by the RTCVD (Rapid Thermal Chemical Vapor Deposition) method were described. For the growth of Si_(l-x)Ge_x heteroepitaxial layers, SiH₄/ GeH₄ / H₂ gas mixtures were used. The growth conditions were varied to investigate their effects on the Si / Ge composition ratios, the interface abruptness and crystalline properties. The experimental data shows that the misfit threading dislocation in Si_(l-x)Ge_x / Si heteroepitaxial film of about 400 A thickness was not observed at the growth temperature of as low as 650℃, and the composition ratios of Si / Ge changed linearly with SiH₄ / GeH₄ gas mixing ratios in our experimental ranges. In the in-situ boron doping experiments, the doping abruptness would be controlled within several hundreds Å/decade.
Removal of NH3, H2S and Toluene by Biofilters Packed with Rock Wool-Compost Media
정욱진,Melvin Maaliw Galera,Eulsaeng Cho Enkhdul Tuuguu,Shin-Jung Park,Danvir Mark Farnazo,Chankyu Jee,Nam Jong Yoo 한국공업화학회 2007 Journal of Industrial and Engineering Chemistry Vol.13 No.6
Biofiltration is carried out in packing materials where attached microorganisms degrade the passing contaminant. In this work, a new packing material was introduced and evaluated for the treatment of malodorous gases-ammonia and hydrogen sulfide and a volatile organic compound-toluene in three biofilters, BF1, BF2, and BF3, respectively. The new composite rock wool-compost media consisted of rock wool and compost in 70:30 weight ratios. Above 95 % removal efficiencies were obtained as the inlet concentrations of ammonia, hydrogen sulfide and toluene were increased up to 155, 150 and 260 ppmv, respectively in the biofilters at an empty bed residence time of ∼65 s. The removal efficiencies in the hydrogen sulfide (BF2) and toluene (BF3) biofilters immediately decreased when the frequency of water irrigation was reduced. However, hydrogen sulfide removal in the BF2 could be improved in some extent by maintaining pH of above 5. Parameters such as pH, microbial count, and pressure drop along the biofilters were also evaluated. The highest elimination capacities obtained from the study were 6.4 g-NH3/m3/h, 12.1 g-H2S/m3/h, and 57.6 g-toluene/m3/h, indicating that the rock wool-compost media can be suitably and effectively applied for biofiltration.
CFD-DEM 연동을 통한 함정용 채프운의 시공간 분포 해석
정욱진,김문홍,손동우,Uk Jin Jung,Moonhong Kim,Dongwoo Sohn 한국전산구조공학회 2023 전산구조공학 Vol.36 No.2
Warships widely spread numerous chaffs using a blast, which form chaff clouds that create false radar cross-sections to deceive enemy radars. In this study, we established a numerical framework based on a one-way coupling of computational fluid dynamics and discrete element method to simulate the spatiotemporal distribution of chaff clouds for warships in the air. Using the framework, we investigated the effects of wind, initial chaff cartridge angle, and blast pressure on the distribution of chaff clouds. We observed three phases for the chaff cloud diffusion: radial diffusion by the explosion, omnidirectional diffusion by turbulence and collision, and gravity-induced diffusion by the difference in the fall speed. The wind moved the average position of the chaff clouds, and the diffusion due to drag force did not occur. The direction of radial diffusion by the explosion depended on the initial angle of the cartridge, and a more vertical angle led to a wider distribution of the chaffs. As the blast pressure increased, the chaff clouds spread out more widely, but the distribution difference in the direction of gravity was not significant.
CFD-DEM 연동을 통한 함정용 채프운의 시공간 분포 해석
정욱진,김문홍,손동우 한국전산구조공학회 2023 한국전산구조공학회논문집 Vol.36 No.2
수많은 함정용 채프들은 폭발에 의해 확산되어 채프운을 형성하며, 채프운은 허위 레이더 반사 단면적을 생성하여 적의 레이더를 기만한다. 본 논문에서는 전산유체역학-이산요소법 단방향 연동 기법을 기반으로 공기 중에 분포하는 함정용 채프운의 시공간 분포를 해석하는 수치적 프레임워크를 구축하고 바람의 방향과 속도, 채프 카트리지의 초기 각도와 폭발 압력이 채프운 분포에 미치는 영향을 분석하였다. 채프운의 확산은 폭발에 의한 방사형 확산, 난류와 충돌에 의한 전 방향 확산, 낙하 속도 차이에 의한 중력 방향 확산과 같이 세 단계로 구분되는 것을 확인하였다. 바람은 채프운의 평균 위치를 이동시켰으며, 항력에 의한 확산 효과는 나타나지 않았다. 카트리지 초기 각도에 따라 폭발에 의한 방사형 확산 방향이 달라졌으며, 각도가 지면과 수직에 가까울수록 더 넓게 확산되었다. 폭발압력이 증가할수록 채프운은 더 넓게 확산되었으나 중력 방향으로는 분포 차이가 작았다.