• Proceedings of the Korean Vacuum Society Conference
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• 2011.08a
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• pp.343-343
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• 2011

저온에서의 Thin Film Transistor (TFT) 혹은 Nonvolatile memory (NVM) 등의 MOS 구조 소자들의 높은 전기적 특성에 관한 연구들이 진행 되면서 mobility와 stability 그리고 구조화의 용이성에 대한 연구가 진행됨에 따라 amorphous silicon의 결정화를 통해 전기적 특성을 향상 시킨 Nanocrystalline silicon (nc-Si)/Microcrystalline silicon (${\mu}c$-Si)에 대한 연구가 관심을 받고 있다. 본 논문에서는 ${\leq}300^{\circ}C$에서 Inductively coupled plasma chemical vapor deposition를 이용한 TFT을 제작하였다. 가스비, 온도, 두께에 따른 결정화 정도를 Raman spectra를 통해 확인한 후 Bottom gate와 Top gate 구조의 TFT를 제작 하고 결정화에 따른 전기적 특성 향상과 그의 덧붙여 플라즈마 처리를 통한 특성 향상을 확인 하였다.

• Journal of the Korean Institute of Gas
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• v.2 no.1
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• pp.99-106
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• 1998

In order to investigate the impact properties of structural materials for LNG tank, instrumented Charpy impact tests were carried out at cryogenic temperatures. $9\%$ Ni steel showed a superior fracture resistance because of less degradation in toughness until 77 K. From the load-deflection curve obtained by an instrumented methods it was found that with the decrease of temperature from 173 K to 77 K, the peak load in the curve increased, but the total absorbed energy decreased. In addition, the energy absorbed during the crack growth was larger than one absorbed in the process of crack initiation. In SUS304L material, the energy absorbed in the process of the crack initiation was relatively large, but the energy absorbed in the process of crack growth was small, the behavior of absorbed energy was well agreed with the observations of the fracture surface which showed a relatively smooth fracture surface. The absorbed Charpy impact energy in the case of A5083 alloy was lower as compared with other steels, and some cracks were observed along the crack propagation direction at the fracture surface of 77 K.

• Proceedings of the Korean Institute of Industrial Safety Conference
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• 1999.06a
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• pp.115-120
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• 1999

현재 소방법 기술기준 소방대상물 및 위험물별 소화설비의 적용성에 의하면 전산실, 전기실, 통신기기실에 모두 설치가 허용된 소화선비는 이산화탄소 소화설비, 할로겐화 소화설비 및 가스계 소화설비 뿐이다. 이러한 이유에서 불연성 가스인 이산화탄소 소화설비는 설치비용이 저렴하고 소화 후 증거 보존이 양호하고 그 청결성 등으로 인하여 화재의 소화뿐만 아니라 화재예방, 인화폭발의 예방에도 적당한 것으로서 많이 이용되고 있다. (중략)

• Clean Technology
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• v.20 no.3
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• pp.218-225
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• 2014

Catalytic gasification of raw coals at mild condition is not realized yet mainly due to deactivation of catalysts via their irreversible interaction with mineral matters in coal. In this work, the gasification behavior of ash-free coal (AFC) was compared with that of the parent raw coal. In order to modify the gasification conditions, the raw coal gasified with fixed variables (water supply, space velocity, temperature, catalysts) in a fixed bed reactor. When catalysts are added by physical mixing method with coal, $K_2CO_3$ was the most effective additives for steam gasification of coal. However, the activity of ash-free coal (AFC) was much less reactive than raw coal due to high temperature extraction in a 1-methylnaphthalene under 30bar at $370^{\circ}C$ for 1 h, almost removed oxygen functional groups, and increased carbonization. The addition of $K_2CO_3$ in AFC achieved higher conversion rate at low temperature ($700^{\circ}C$). At that time, the molar ratio of gases ($H_2/CO$ and $CO_2/CO$) was increased because of water-gas shift reaction (WGSR) by addition of catalysts. This shows that catalytic steam gasification of AFCs is achievable for economic improvement of gasification process at mild temperature.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1999.10a
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• pp.1-1
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• 1999

2유체 동축인젝터(coaxial twin fluid injector)는 액체산소와 액체수소를 추진제로 사용하는 SSME(Space Shuttle Main Engine)이나 유럽의 Arian 5 Vulcain 엔진과 같은 저온추진제 엔진에 널리 사용되고 있다. 추진제를 미립화 시키는 장치로서 사용하는 다른 여러 형태의 인젝터에 비교할 때 저속의 액체산화제 주위에 고속의 가스연료가 분사됨으로서 발생되는 전단력에 의해 추진제가 미립화되는 특징을 가지며, 이러한 메카니즘은 매우 복잡하여 아직까지 정확히 규명되지 못하고 있는 실정이다.

• Journal of Energy Engineering
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• v.19 no.4
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• pp.215-220
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• 2010

Hydrogen is a clean and efficient energy source and is expected to take an important role in future energy demand. A possibly good route to produce hydrogen is by using biomass and organic wastes as a source through thermo-chemical conversion technology. In this study, pyrolysis of wood Pellet(Oregon pine) has been carried out in batch type fixed-bed reactor in $N_2$ atmosphere during 20 minutes to determine the optimum hydrogen generating conditions. At the influence of temperature, hydrogen yield was increased with increasing temperature. For the influence of Steam/Biomass Ratio(SBR), hydrogen yield was increased by steam addition at low temperature condition. However, effect of steam addition was insignificant over at SBR = 1. The hydrogen yield was increased with increasing SBR at high temperature condition. From result of $H_2$/CO and $H_2/CH_4$ ratio, dominant reaction was steam reforming in this experimental condition. The optimum condition for hydrogen production was determined as follows: $H_2$ yield = 38.3 vol.% (56.01 L/min kg) at $900^{\circ}C$, SBR=3.

• 한국신재생에너지학회:학술대회논문집
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• 2010.06a
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• pp.219.2-219.2
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• 2010

가스하이드레이트(gas hydrate)는 고압과 저온 조건에서 물분자간의 수소결합으로 형성되는 3차원 격자구조에 동공(cavity)이라는 빈 공간이 생기고 이 동공에 가스가 물리적으로 포획되어 생성되는 것으로, 수소결합을 하는 물의 격자(Host) 내에 메탄등의 저분자가스(Guest)가 포획된 결정체이다. 가스 하이드레이트는 미량의 물을 첨가, 가압하면 부피비로 약 200배의 가스를 고상의 형태로 저장할 수 있으며, 열역학적으로 안정된 결정체이기 때문에 하이드레이트로 존재하기 위한 최소한의 온도, 압력조건이 충족되면 고상으로 항구적인 존재가 가능할 수 있어 가스의 수송 및 저장에 높은 경제성을 가지는 방법이다. 현재 운영중인 전국의 242개소 매립지 중에서 발전 및 연료로 활용가능한 조건을 같춘 자원화 대상 매립지는 약 14곳에 불과한 형편이고 이들 중 대부분 시설은 자원화 시설을 운영하고 있으나. 중소규모 매립지에서 발생하는 LFG에 대하여 효율적인 이용 및 처리 방안이 없어 태워 없어지거나 방치하는 등 매립가스를 활용하는 기술은 미흡한 실정이다. 이러한 LFG는 많은 환경적인 문제를 야기하지만, 50vol% 이상의 고농도 메탄이 함유되어 있어 이를 대체에너지원으로 이용할 경우 환경적인 문제를 해결함과 동시에 신재생에너지원으로 활용 가능하다. 본 연구에서는 중소규모 매립지에서 발생하는 LFG를 활용하기 위하여 하이드레이트 형성/해리 Pilot plant의 제작을 통하여 $CH_4$와 $CO_2$(단일, 복합가스의 실험)의 하이드레이트화 연구를 진행 중이다.

• Journal of Bio-Environment Control
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• v.28 no.2
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• pp.166-171
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• 2019

This study was conducted to investigate the effect of gaseous chlorine dioxide ($ClO_2$) concentration and treatment method for maintaining marketability in strawberries 'Maehyang' for export. After harvesting strawberry colored with $60{\pm}5%$ of the skin, and the gaseous $ClO_2$ was applied as four treatments in the cold store set with $10^{\circ}C$ which were as follows: i) non-treatment (Control), ii) $0.2mg{\cdot}L^{-1}$ for 30 minutes, iii) $0.4mg{\cdot}L^{-1}$ for 30 minutes, and iv) continuously exposed at $0.4mg{\cdot}L^{-1}$ during the storage period. Weight loss, firmness, soluble solids content, color, incidence of gray mold, and quality grade of strawberries were investigated every 3 days during 16 days storage in cold store. The weight loss was consistently high at $0.2mg{\cdot}L^{-1}\;ClO_2$ treatment, and the weight loss was lower than other treatments when gaseous $ClO_2$ was continuously treated. Firmness was significantly higher at 0.2 and $0.4mg{\cdot}L^{-1}$ $ClO_2$ treatment on the 13th day of storage. Soluble solids content tended to below in continuous gaseous $ClO_2$ treatment. The colors showed no tendency as affected by concentrations and treatment methods of gaseous $ClO_2$. No gray mold was observed in the continuous gaseous $ClO_2$ treatment until the 13th day of storage. The quality grade was lower in gaseous $ClO_2$ treatment group than in the control. As a result, it was possible to decrease the weight loss and the incidence of gray mold by continuously treating the gaseous $ClO_2$ to strawberry 'Maehyang' for export during the storage period after harvest. However, further research is needed on method to maintain quality grades of fruits.

• Applied Chemistry for Engineering
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• v.17 no.4
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• pp.414-419
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• 2006

Effects of water vapor, hydrocarbons, and CO, which are inevitably included in exhaust gases of combustion, on a combined $De-NO_{x}$ process of non-thermal plasma and $NH_{3}$ SCR (Selective Catalytic Reduction) have been investigated. Test results showed that fast SCR reaction enhanced $De-NO_{x}$ rate under the low temperature conditions, $150{\sim}200^{\circ}C$ The present test, however, showed that the role of the fast SCR reaction can be significantly suppressed by addition of hydrocarbons in a non-thermal plasma reactor. Detailed investigation verified that such suppressed role of the fast SCR reaction could be caused by the $NO_{2}/NO_{x}$ ratio modified by aldehydes produced from hydrocarbons in a non-thermal plasma reactor. In addition, the present study was confirmed that the effects of water vapor and CO were not noticeable compared with the hydrocarbon effects.

• Applied Chemistry for Engineering
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• v.17 no.1
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• pp.1-11
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• 2006

Non-thermal plasma technology for air pollution control, which are NOx, SOx, VOCs, soot, etc., is reviewed. In the early parts of the paper, generation of non-thermal plasma and plasma chemical process are introduced to provide an appropriate plasma condition (electron energy density) for treating air pollutions. Recent results on numerical simulation, optical diagnostics, and gas treatment are provided to characterize an optimal design of plasma generation and plasma chemical process. These data are also helpful to understand unique features of non-thermal plasma process that is achieved with relatively low temperature conditions, i.e. low enthalpy conditions of the treated gas molecules. In the later parts of the paper, several examples of recently developed non-thermal plasma techniques are illustrated, in which technical and economical assessments of the present techniques are provided.