• 한국가스학회지
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• 제18권1호
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• pp.25-30
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• 2014

수소와 압축천연가스의 혼합연료 HCNG의 가스공급 및 충전을 위해 혼합장치 제작 및 충전실험을 수행하였다. 비율제어방식 개념으로 수소와 압축천연가스는 30 : 70의 비율로 혼합된다. HCNG 충전방법으로는 탱크의 압력을 이용하여 충전할 수 있는 FULL충전, 일정량을 충전할 수 있는 정량충전 방식이 있다. Full충전과 정량충전 결과 모두 혼합비율 30 : 70에 오차 제한범위인 수소$30{\pm}2%$ 조건을 만족시켰다. 탱크에 충전된 HCNG의 조성을 Gas Chromatography로 분석한 결과도 오차제한범위를 만족시켜 충전탱크에서도 30 : 70의 비율을 확인하였다.

• Journal of Welding and Joining
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• 제27권3호
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• pp.38-43
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• 2009

The optimization of the welding parameters was studied to maximize the weldability and minimize the amount of spatter in the MAG welding of automotive steel sheets under different shielding gas composition ratio. JS-EFSC, JS-SPHC steel plates and Ar mixture gases were used as a substrate and shielding gas for welding respectively. The five welding parameters were selected through preliminary experiments and their effects on the weldability were analyzed. Experiments were performed using the Taguchi experimental method. As results, appropriate range for welding could be achieved. Amount of spatter in 80%Ar+20%$CO_2$ shielding gas was 20% of that of $CO_2$welding. Therefore, in terms of high productivity and welding cost, Ar mixture gas(80%Ar+20%$CO_2$) was recommended as a shielding gas for application of MAG process, indicating the low spatter and good weld quality.

• Applied Biological Chemistry
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• 제39권4호
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• pp.255-259
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• 1996

된장의 발효 숙성 과정중 경시적으로 분리친 180주의 효모를 동정한 결과 Candida rugosa, Candida zelyanoides, Pichia farinosa, Sacccharomyces cerevisiae, Zygosaccharomyces rouxii 등 4속 5종으로 분리 동정되었다. 이들 효모 중 가스 및 알콜 생성능이 높은 효모는 S. cerevisiae와 Z. rouxii였으며, 특히 Z. rouxii는 속성 14일째 26%, 30일째는 76%의 분리빈도를 보여 된장의 발효숙성에 주로 분포되는 효모로 나타났다. 된장 발효숙성중의 효모수는 숙성초기부터 서서히 증가하여 숙성 14일 경과시 초기보다 약 30배 증가하여 최고수준에 이르렀으며, 이후 감소하기 시작하여 숙성 60일째는 숙성초기 효모수 보다 낮게 나타났다. 발효 속성중 에탄올은 숙성 30일째 1.87%가 생성되었고, 이후 60일째 까지 2.19%로 완만히 증가하였다. 가스생성은 숙성 14일의 시료 된장에서 가장 많았으며 보존중 최대 가스 생성량은 9.75ml/g이었으며 30일째의 시료 된장에서는 4.5ml/g로 가스 생성이 감소되었고, 숙성 45일과 60일째의 시료에서 가스생성이 억제된 것은 발효숙성시 생성된 에탄올로부터 기인되는 것으로 생각된다.

• 폴리머
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• 제37권5호
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• pp.553-556
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• 2013

본 연구에서는 고분자 수화젤 비드 내부에 아세트산을 탑재시킨 후, 분무와 함께 수화젤로부터 방출된 아세트산이 아염소산나트륨과 반응하여, 저농도의 이산화염소 기체를 장시간 지속적으로 발생시킬 수 있는 장치를 개발하였다. 폴리아크릴아미드 수화젤 비드에 탑재시킨 아세트산의 함량과 부직포에 코팅한 아염소산나트륨의 함량을 변화시키면서 발생하는 이산화염소 기체의 생성량을 측정한 결과, 수화젤로부터 아세트산이 방출된 후 반응을 하기 때문에 직접반응에 의한 것보다 반응시간이 지연되어 저농도의 이산화염소 기체가 지속적으로 생성되도록 제어하는 것이 가능하였다. 이러한 결과는 본 연구가 목적으로 하는 저농도의 이산화염소를 장시간에 걸쳐서 지속적으로 생성할 수 있는 장치를 고분자 수화젤을 이용하여 구현할 수 있음을 보여준다.

• 환경위생공학
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• 제10권3호
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• pp.124-130
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• 1995

Air pollution problem by air craft was reviewed from emission gas components from air craft and pollutants amount generated in airport with the compareness of domestic transportation data by airplane and foreign data. It is reported that concentration of emission gas from air craft is lower than that of pollutants from automobile and factory. But transportation frequency is increasing rapidly in Korea. It is recommended that concerns should be taken on long- term of counterplan device about it.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2002년도 ICCAS
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• pp.69.6-69
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• 2002

The optimal byproduct gas supply system was developed for the optimal management of the byproduct gases in the iron and steel making process based on EXCEL environment. It supplies optimal byproduct gas distribution result as well as analysis including expected electricity generation, holder level change, amount of oil consumption, energy distribution to each boiler, and efficiency of energy resource. To reflect the changing environment of the plant such as maintenance, the system was developed to easily change the optimization model for changing configuration of the system. To verify the performance of the system , case studies for various situation was performed with the developed system, a...

• 한국분말야금학회:학술대회논문집
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• 한국분말야금학회 2006년도 Extended Abstracts of 2006 POWDER METALLURGY World Congress Part 1
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• pp.391-392
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• 2006

Sintered materials have been applied widely in Valve Seat Inserts (VSI). The amount of wear on VSIs increases when used in gas (LPG, CNG) engines because of their dry environments. In this paper, two newly developed high performance VSI materials for gas engines are introduced. These materials applied new techniques, which are both high performance hard particle and new distribution method of solid lubricant, to increase wear resistance.

• Bulletin of the Korean Chemical Society
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• 제33권3호
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• pp.901-905
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• 2012

In this study, we investigated the pure geometrical effect of porous materials in gas adsorption using the grand canonical Monte Carlo simulations of primitive gas-pore models with various pore geometries such as planar, cylindrical, and random pore geometries. Although the model does not possess atomistic level details of porous materials, our simulation results provided many insightful information in the effect of pore geometry on the adsorption behavior of gas molecules. First, the surface curvature of porous materials plays a significant role in the amount of adsorbed gas molecules: the concave surface such as in cylindrical pores induces more attraction between gas molecules and pore, which results in the enhanced gas adsorption. On the contrary, the convex surface of random pores gives the opposite effect. Second, this geometrical effect shows a nonmonotonic dependence on the gas-pore interaction strength and length. Third, as the external gas pressure is increased, the change in the gas adsorption due to pore geometry is reduced. Finally, the pore geometry also affects the collision dynamics of gas molecules. Since our model is based on primitive description of fluid molecules, our conclusion can be applied to any fluidic systems including reactant-electrode systems.

• International Journal of Air-Conditioning and Refrigeration
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• 제6권
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• pp.56-66
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• 1998

The absorption process of water vapor in a liquid film is an important process in LiBr-Water absorption system. The composition of the gas phase, in which a non-absorbable gas is combined with the absorbate, influences the transport characteristics. In the present work, the absorption processes of water vapor into aqueous solutions of lithium bromide in the presence of non-absorbable gas are investigated. The continuity, momentum, energy and diffusion equations for the solution film and gas are formulated in integral forms and solved numerically. It is found that the mass transfer resistance in gas phase increases with the concentration of non-absorbable gas. However the primary resistance to mass transfer is in the liquid phase. As the concentration of non-absorbable gas in the absorbate increases, the interfacial temperature and concentration of absorbate in solution decrease, which results in the reduction of absorption rate. The reduction of mass transfer rate is found to be significant for the addition of a small amount of non-absorbable gas to the pure vapor, especially at the outlet of tube where the non-absorbable gas accumulates. At higher non-absorbable gas concentration, the decrease of absorption rate seems to be linear to the concentration of non-absorbable gas.

• 한국수소및신에너지학회논문집
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• 제27권2호
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• pp.230-235
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• 2016

The purpose of this study is to evaluate the gas leakage for a 30-inch ball valve. The ball valve was designed and manufactured for a natural gas transportation through a long-distance pipeline mainly installed in the permafrost region. The gas leakage assessment is based on the pressure testing criteria of international standards. Pressure conditions of the gas leakage test was employed 70 bar, 100 bar, and 110 bar. The amount of the gas leakage at each pressure condition was small and had a value under the pressure testing criteria, ISO 5208. Gas leakage with respect to the test pressure was predicted by the polynomial curve fitting using the experimental results. It is found that the gas leakage rate according to the pressure is proportion to a second order curve.