• Korean Chemical Engineering Research
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• v.45 no.4
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• pp.384-390
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• 2007

In this study, electroless plating of copper was performed on PET film by using the blend of supercritical $CO_2$ and plating solution. The optimum volumetric ratio of supercritical fluid and plating solution was found to be 1:9 and dispersion property was poor at $CO_2$ vol% langer than 10%. Electroless plating of copper was best at $25^{\circ}C$ and 15 MPa. Role of added supercritical $CO_2$ is not to increase solubility but to disperse and maintain Cu-particles as the 1st particles.

• Proceedings of the Materials Research Society of Korea Conference
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• 2003.11a
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• pp.145-145
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• 2003

자성유체는 암 치료와 질병진단 등과 같은 다양한 분야에서 유용한 응용의 가능성을 갖는다 [1]. 생리적 염도인 중성 pH에서 생체조직과 잘 교합하고, 높은 안정성을 가지는 자성유체는 자성 나노입자 표면에 화학적으로 흡착된 계면활성제 종류에 따라 달라진다 [2]. 본 실험에서는 화학적 공침법을 이용하여 Fe$^{2+}$와 Fe$^{3+}$ 의 몰비가 1:2인 수용액에 pH 12 이상의 과잉 알칼리(NH$_4$OH 12ml)를 첨가시켜 마그네타이트 콜로이드 용액을 제조하였다. 광감제로는 hematoporphyin을 사용하였으며 투입량은 1$\times$$10^{-3}$mol/l 였다. 또한 1차 및 2차 계면활성제로는 decanoic acid와 starch, citric acid, oleic acid 등이 각각 사용되었다. 각 계면활성제가 코팅된 자성미립자의 특성을 조사하기 위해 동결 건조 후 VSM, FT-IR 및 TEM 분석을 수행하여 자기적 특성과 코팅표면의 결합구조 및 미시적 구조를 분석하였다. 그리고, 각각의 계면활성제가 코팅된 자성유체의 독성을 조사하기 위해 rat를 이용한 생체실험이 병행되었다.

• Nuclear Engineering and Technology
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• v.25 no.2
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• pp.233-236
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• 1993

For one-dimensional two-phase flow without phase change and without axially-temporally rapid change of pressure, the interrelationship between the drift-flux model and the two-fluid model is studied. It is derived on the basis of the fact that the vapor conservation equation is related to the momentum equation by the drift flux. Starting from the two-fluid model, we obtain the interfacial friction expressed in terms of drift-flux parameter. Also, by deriving the void propagation equation, the drift-flux is shown to have jnterrelationship with forces in the two-fluid model.

• 유체기계공업학회:학술대회논문집
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• 2006.08a
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• pp.145-146
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• 2006

Recently, the next-generation advanced flow visualization techniques such as holographic PIV, dynamic PIV, echo-PIV, micro/nano-PIV, and X-ray PIV have been introduced. These advanced measurement techniques have a big potential as the core technology for analyzing outmost thermo-fluid flows in future. These would be indispensable in solving complicated thermo-fluid flow problems not only in the industrial fields such as automotive, space, electronics, aero- and hydro-dynamics, steel, and information engineering, but also in the research fields of medical science, bio-medical engineering, environmental and energy engineering etc. Especially, NT (Nano Technology) and BT (Bio Technology) strongly demand these advanced measurement techniques, because it is impossible for conventional measurement methods to observe most complicated nano- and bio-fluidic phenomena. In this presentation, the basic principle of these high-tech flow visualization techniques and their practical applications which cannot be resolved by conventional methods, such as blood flows in a micro-tube, in vivo analysis of micro-circulation, and flow around a living body will be introduced as a blue ocean strategy.

• 한국전산유체공학회:학술대회논문집
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• 2007.10a
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• pp.27-31
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• 2007

Glass particle distribution in a stirred solid/liquid systems was investigated using computational fluid dynamics(CFD). The numerical results were compared to experimental data from the available literature which investigated the local dispersed phase volume fraction by means of an endoscope technique. Eulerian multi-phase model and applications considered high loading of solid particle was used to investigate the influence of the particle concentration and mixing tank size on the solid distribution. A good agreement was obtained between the experimental data and simulation results. The results showed different solid particle distribution in an agitator by particle concentration and mixer size.

• 한국전산유체공학회:학술대회논문집
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• 2010.05a
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• pp.524-529
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• 2010

In the present study, a CFD program is developed for the Fluid-Structure Interaction(FSI) analysis. The non-staggered, non-orthogonal, and unstructured grid system was also used to handle the complicated geometries in the program. In order to validate the capabilities of the developed CFD program, various models are investigated by using unstructured and nonorthogonal meshes. The predicted results are a good agreement with analytic solution, experimental data and commercial software. And also PISO algorithm is applied for transient flow analysis. The cyclic boundary condition and baffle cell are developed in order to improve the effectiveness of the calculation for complex geometry.

• 한국전산유체공학회:학술대회논문집
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• 2008.03a
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• pp.181-185
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• 2008

In this study, we attempted to quantify the relative importance of assumptions regarding blood rheology. Three patient-specific carotid bifurcation geometries and time-varying flow rates were obtained using magnetic resonance imaging. For each subject, CFD simulations were carried out assuming two different non-Newtonian rheology models Carreau and Ballyk models) and rescaled Newtonian viscosities based on characteristic shear rates to account for the shear-thinning property of blood. The sensitivity of WSS and oscillatory shear index (OSI) were contextualized with respect to the reproducibility of the reconstructed geometry and to assumptions regarding the inlet boundary conditions. We conclude that the assumption of Newtonian fluid is reasonable for studies aimed at quantifying the distribution of WSS-based extrema in an image-based CFD model of carotid bifurcation.

• 한국전산유체공학회:학술대회논문집
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• 2008.10a
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• pp.181-185
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• 2008

In this study, we attempted to quantify the relative importance of assumptions regarding blood rheology. Three patient-specific carotid bifurcation geometries and time-varying flow rates were obtained using magnetic resonance imaging. For each subject, CFD simulations were carried out assuming two different non-Newtonian rheology models (Carreau and Ballyk models) and rescaled Newtonian viscosities based on characteristic shear rates to account for the shear-thinning property of blood. The sensitivity of WSS and oscillatory shear index (OSI) were contextualized with respect to the reproducibility of the reconstructed geometry and to assumptions regarding the inlet boundary conditions. We conclude that the assumption of Newtonian fluid is reasonable for studies aimed at quantifying the distribution of WSS-based extrema in an image-based CFD model of carotid bifurcation.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.152-152
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• 2014

최근 반도체의 고집적화로 high dose implant 도입과 소자의 동작 특성 향상을 위한 low-k 물질 도입에 따라 다양한 주변 공정의 변화를 이끌고 있다. 이에 따라 반도체 제조의 핵심 공정 단계 중 하나인 ashing 단계에서 기존 성능 이상의 장비를 기대하고 있으며, 그것을 평가하기 위한 중요 요소로 uniformity와 fast stripping이 있다. 본 연구에서는 유체해석 시뮬레이션을 통해 450 mm ashing 챔버에서의 gas inlet baffle과 wafer stage 사이의 최적 거리를 예측했다. 우선적으로 시뮬레이션의 신뢰도를 높이기 위해 실험으로 측정한 300 mm ashing 결과와 유체해석 결과 molecular flux의 상관관계를 파악하여, 450 mm ashing 챔버의 최적 구조를 예측하였다. 선행 연구한 300 mm 시뮬레이션 결과를 바탕으로 이상적인 450 mm ashing 챔버를 설계하였다. 유체해석 결과는 동일한 형태의 수직형 구조 장비에서 baffle과 wafer stage 사이의 거리가 35 mm에서 60 mm일 때, 450 mm wafer surface 위에서 더욱 균일한 density 분포를 나타내었다. Reactant flux 분포는 거리가 60 mm에서 80 mm 사이일 경우 더 균일하게 나타났다. 그러므로, 450 mm 챔버에서 gas inlet baffle과 wafer stage 간격이 60 mm일 때 최적의 구조로 판단된다.

• Journal of ILASS-Korea
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• v.13 no.1
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• pp.16-21
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• 2008

In the present study, the 2-fluid nozzle and 3-fluid nozzle to atomize the diesel and water with air for the fuel reformer of SOFC system were experimentally examined. In the 2-fluid nozzle, the diesel and water were alternately atomized due to bislug flow pattern, and it implies that the mixing of both liquids strongly affects the atomization pattern. On the other hand, in the 3-fluid nozzle, the diesel and water were atomized simultaneously due to the separated injection channels without mixing problem. Therefore, compared to the 2-fluid nozzle, the 3-fluid nozzle is suitable for the stable operation of the fuel reformer. In case of the 3-fluid nozzle, Type A where the air was supplied through the central channel was the most efficient.