• Solar Energy
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• v.12 no.3
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• pp.107-115
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• 1992

An experiment was performed to study solidification of binary mixture with double-diffusive convection in the liquid. A rectangular enclosure was filled with ammonium chloridewater solution. The phase change and convection process were studied through shadowgraph. Becasuse of the double-diffusive convection, the temperature field and concentration filed were stratified very rapidly. Correlation between solidified mass fraction and the dimensionless numbers was found; solidified mass concentration can be expressed as a linear function of $(Ste{\cdot}Ra^{1/4})^{2-Ste}{\cdot}Fo^{1/2}$.

• Transactions of the Korean Society of Mechanical Engineers
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• v.19 no.4
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• pp.1095-1101
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• 1995

Numerical analysis of vertical solidification process allowing solid-liquid density change is performed by a hybrid method between a winite volume method (FVM) and a finite element method (FEM). The investigation focuses on the influence of solid-liquid density change and cooling rates on the motion of solid-liquid interface, solidified mass fraction, temperatures and thermal stresses in the solid region. Due to the density change of pure aluminium, solid-liquid interface moves more slowly but the solidified mass fraction is larger. The cooling rate of the wall is shown to have a significant influence on the phase change heat transfer and thermal stresses, while the density change has a small influence on the motion of the interface, solidified mass fraction, temperature distributions and thermal stresses. As the cooling rate increases, the thermal stresses become higher at the early stage of a solidification process, but it has small influence on the final stresses as the steady state is reached.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.54.2-54.2
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• 2011

야금학적 정련 공정 중 슬래그 처리, 일방향 응고, 플라즈마-전자기유도용해 공정을 적용한 태양전지용 실리콘 제조 기술에 관한 연구를 수행하였다. 원소재인 금속급 실리콘을 제조하기 위해원재료로 규석, 코크스(Cokes), 숯, 그리고 우드칩(Wood chip)을 사용하였으며, 150kW급 DC 아크로(Arc furnace)를 이용하여 순도 99.8% 금속급 실리콘을 제조하였다. 제조된 용융 상태의 금속급 실리콘은 슬래그와 반응시켜 불순물을 제거하였다. SiO2-CaO-CaF2 계의 슬래그를 이용하였으며, 금속급 실리콘과 슬래그의 질량비 및 반응 시간에 따른 실리콘 불순물 특성을 평가하였다. 이후 고액 계면이 제어 가능한 일방향 응고 장치를 이용하여 금속불순물을 제거하였다. 고액상태의 온도 조건 및 응고 시간에 따른 불순물 농도 변화를 평가하였으며, 순도 6N급의 실리콘을 제조하였다. 마지막 공정으로 스팀 플라즈마 토치와 냉도가니가 적용된 전자기 유도 용해장치를 이용하여 붕소와 인을 제거하였다. 플라즈마 토치 가스로는 아르곤, 스팀, 수소를 이용하였다. 붕소와 인의 제거율은 각각 94%와 96%를 달성하였으며, 최종 순도 6N급의 실리콘을 제조하였다.

• Korean Journal of Clinical Laboratory Science
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• v.51 no.2
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• pp.260-264
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• 2019

An 84-year-old woman presented to the emergency department with a chief complaint of pressure sores of the anus. She had a urine catheter when she showed pyuria three times but had no fever. A microscopic examination revealed many grapevine-like Gram positive strains and neutrophils. After 24 hours of urine culture on blood agar, non-hemolytic mucous colonies were found and further enlarged after 48 hours of culture. The capsules were identified after India ink stain. The catalase was positive, but the tube coagulase and latex coagulase were both negative. The S. aureus was identified by Vitek-2 and mass spectrometer Vitek MS V-3 IVD. The strain was confirmed by 16S rRNA gene sequencing and multilocus sequence typing (MLST). The phenotypically atypical MRSA found in the tube coagulase and latex coagulase were both negative. MRSA often show no beta hemolysis as in this case but are rarely latex coagulase-negative. We report a woman whose urine culture showed non-hemolytic, tube coagulase-negative, and latex coagulase-negative MRSA.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.44 no.10
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• pp.887-894
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• 2016

The thermal control device using solid-liquid phase change material (PCM) is designed, manufactured, and experimented in thermal environment chamber. The n-Hexadecane is selected as a PCM and its melting point is placed within the component working temperature range. The PCM container is made of Al6061 and has the thermal spreading fins inside. To simulate the working condition for on-orbit satellite the heat pipes are used to connect the heater and radiator and the PCM thermal control device (PCMTD) is installed at the middle portion of heat pipes. The thermal buffer mass (TBM), which is same configuration and volume with PCMTD, is also manufactured to compare the thermal control performance. As a result, the PCMTD is not only more efficient than TBM in their temperature control features but both mass and power of compensation heater are reduced.