• 한국분말재료학회지
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• 제12권1호
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• pp.64-69
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• 2005

The copper oxide nano powders were synthesized by levitational gas condensation(LGC) method, and their high heterogeneous catalytic effects of oxidation of 2,3,5-trimethyl-1,4- hydroquinone (TMHQ) and catalase activity were studied. The observation of transmission electron microscopy (TEM) shows that most of these nano powders are uniform in size, with the average particle size of 35 nm. The nano powder consists of mainly $Cu_2O$, but it is aged to CuO phase. The catalytic effect which was clarified by oxidation of TMHQ and catalase depends on the amount of cuprite phase and the particle size.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.158-159
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• 2006

Ultrafine Au-Pb particles prepared by two method, (1) simultaneous evaporation of Au and Pb in inert gas and (2) subsequent vapor condensation of Pb in a differentially evacuated tube onto flying Au nanoparticles prepared by gasevaporation technique, were observed by electron microscopy. In the method (1), the particles that grew at the region where the two smoke masses converged, consisted of alloy phases. In the method (2), the particles consisted of two or three phases of Au, $Au_2Pb$, $AuPb_2$ and Pb phases in turn from the inner part, Pb-rich particles being composed of only two phases of $AuPb_2$ and Pb.

• Transactions on Electrical and Electronic Materials
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• 제5권4호
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• pp.161-165
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• 2004

In order to get oxidizing power enough for growth of a superconductive thin film with oxide gas, concentrated ozone was used. As a method for concentrating ozone, a method for concentrating ozone by adsorbing ozone selectively into silica-gel beads is adopted, and this concentration is analyzed by the ultraviolet absorption method, the thermal decomposition method and the Q-mass analyzing method. Thermal decomposition method is most effective for measurement of a high concentration of ozone. Ozone as concentrated by the adsorption method got to have a concentration of 97 mol % at the maximum, and it was identified that the concentration of the ozone gas was stable for the time while a thin film was formed.

• 한국입자에어로졸학회지
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• 제9권4호
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• pp.247-252
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• 2013

Removal of water contents in a gas is needed in industrial field of gas processing related on energy production/conversion, and environmental treatment. Inertial separators are economic devices for separating droplets from the gas stream. For design and incorporation of inertial pre-treatment separator, characteristics of removal of water contents with various operation conditions are needed. In this study, removal efficiency of water droplets at various flowrates (5-14 SCMM) and relative humidity (R.H.) conditions (40%, and 90%) has been investigated. At low R.H. condition, the removal characteristic is similar to the removal of solid particles. But, droplet growth resulting from the condensation of water vapor at high R.H. condition, is significant and it made increase in removal efficiency of droplet phase of water contents. For rapid removal of water contents, an effective method to enhancing condensation growth of water droplets is highly needed.

• 대한기계학회논문집B
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• 제27권12호
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• pp.1667-1672
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• 2003

In contrast to the high demand for MEMS devices, microflow analysis is not feasible even for single-phase flow with conventional Navier-Stokes equation because of non-continuum effect when characteristic dimension is comparable with local mean free path. DSMC is one of particle based DNS(Direct Numerical Simulation) methods that uses no continuum assumption. In this paper, gas flow in microchannel is studied using DSMC. Interfacial shear and flow characteristics are observed and compared with the results of gas flow that is in contact with liquid case and solid wall case. The simulation is limited to the case of equilibrium steady state and evaporation/condensation coefficient is assumed to be the same and unity. System temperature remains constant and the interfacial shear appears to be small compared to the result with solid wall. This is because particles evaporated and reflected from the liquid surface form high density layer near the interface with liquid flow.

• 한국자동차공학회논문집
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• 제20권6호
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• pp.140-145
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• 2012

Recently, various after-treatment systems, such as LP-EGR(Low Pressure-Exhaust Gas Recirculation), SCR(Selective Catalytic Reduction) and LNT(Lean NOx Trap), were developed to obey the stringent emission regulations of diesel engine. There are many researches on LP-EGR system because it has advantages of NOx reduction and low fuel consumption. But, condensation water is generated in internal of intercooler tube and it contains various types of anion that cause the corrosion of aluminium tube. In this study, it is examined that the condensation water effects on corrosion of aluminium tube. And method for improvement of corrosion characteristics is investigated using the dipping and electrochemical test.

• Fibers and Polymers
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• 제2권4호
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• pp.178-183
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• 2001

A pitch precursor for a general purpose carbon fiber was prepared by condensation of pyrolized fuel oil (petroleum residual oil) with bromine under nitrogen blowing. such a condensation raised the softening point of the pitch from 4$0^{\circ}C$ to $265^{\circ}$ with a yield of 43%. The pitch precurosr showed an enhanced aromaticity and enlarged molecular size, which led to a reduction in molecular mobility and optical isotropy. The precursor was spun into fibers of $20\mu\textrm{m}$ diameter at a take-up speed of 700m/min. The fiber was stepwise stabilized in air and carbonized in Ar gas to obtain an isotropic carbon fiber. The carbon fiber exhibited tensile strengths of 500-800 ㎫though the fiber was formed via a crude method. The electric conductivity of the carbon fiber was relatively high, 2.2$\times$$10^2$S/cm, sufficient to be used as electrode materials.

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 춘계학술강연 및 발표대회강연 및 발표논문 초록집
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• pp.21-21
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• 2006

• 한국대기환경학회:학술대회논문집
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• 한국대기환경학회 2000년도 추계학술대회 논문집
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• pp.215-216
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• 2000

대기 중에 존재하는 입자의 생성 및 변화를 모델링 하는데 있어서 가장 중요한 요소는 응축/휘발 (condensation/evaporation)과 같은 기체/입자간의 상호 과정을 어떻게 모사 하느냐 하는 것이다. 일반적으로 지금까지의 연구는 입자와 가스상의 농도가 순간적으로 평형을 이룬다고 가정해 왔으나 실제 대기상의 입자는 비 평형(non-equilibrium)상태의 응축/휘발 과정을 따르는 것으로 알려져 왔다. (중략)

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.432-432
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• 2006