• 보존과학회지
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• 제28권4호
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• pp.377-385
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• 2012

박물관에서 문화재 해충의 살충을 위해 사용되어 온 메틸브로마이드는 오존층 파괴물질로써 2015년 사용이 금지됨에 따라 대체법으로써 아르곤이나 질소를 사용한 저산소 농도 살충법이 도입되었다. 국립민속박물관에서는 국내 최초로 저산소 농도 살충법의 적용이 가능한 저산소 농도 살충 챔버 시스템을 시제작하여 설치하였다. 저산소 농도 살충 챔버 시스템은 챔버 내부 용량이 $0.5m^3$이며, 아르곤, 질소, 이산소탄소의 사용이 가능하다. 이 시스템은 산소 농도 0.01~20%, 온도 $10{\sim}50^{\circ}C$, 습도 30~80%를 자동적으로 제어가 가능하며, 산소 농도 제어는 설정값 이상으로 상승할 때마다 가습 가스와 건조 가스를 혼합하여 주입하는 방법을 채택하였다. 시운전을 위해 30일 동안 가동 결과, 산소 농도, 온도 및 습도가 일정하게 유지되었다. 그리고 권연벌레 애벌레와 성충, 애알락수시렁이 애벌레 대해 아르곤 가스를 사용하여 산소 농도 0.01%, 온도 $25^{\circ}C$ 및 습도 50% 환경에서 살충 성능을 평가한 결과, 권연벌레 성충은 3~5일, 애벌레는 7일, 애알락수시렁이 애벌레는 3일이 소요되어, 시제작된 저산소 농도 살충 챔버 시스템의 살충 성능을 확인할 수 있었다. 평가 결과로부터 저산소 농도 살충 챔버 시스템은 박물관에서 메틸브로마이드 대체법인 저산소 농도 살충법의 기술을 개발하는데 충분히 활용이 가능함을 확인하였다.

• 한국화재소방학회논문지
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• 제29권6호
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• pp.20-25
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• 2015

2-Ethylhexanoic acid는 플라스틱의 충격보강제를 제조하는 물질로서 공정 중에 폭발위험성을 고찰하기 위하여 산소농도 변화에 따른 폭발범위, 폭발압력, 최대폭발압력상승속도를 실험한 결과 실험온도 $100^{\circ}C$에서, 산소농도 40~70%에서 폭발하한농도 3.2%를 구하였으며, 산소농도 21%에서 폭발하한 농도는 4.0%, 폭발상한 농도는 4.5%를 구하였다. 또한, 2-ethylhexanoic acid의 폭발압력은 산소농도 70%에서 1.4161 MPa의 최대폭발압력을 나타내었으며, 최대폭발압력상승속도를 구한 결과 산소농도 70%에서 62.692MPa/s를 구하였다.

• Journal of Microbiology and Biotechnology
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• 제21권9호
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• pp.988-994
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• 2011

A significant amount of nitrous oxide ($N_2O$), which is one of the serious greenhouse gases, is emitted from nitrification and denitrification of wastewater. Batch wastewater nitrifications with enriched nitrifiers were carried out under oxygen-limited condition with synthetic (without organic carbon) and real wastewater (with organic carbon) in order to find out the effect of ammonium concentration on $N_2O$ emission. Cumulated $N_2O$-N emission reached 3.0, 5.7, 6.2, and 13.5 mg from 0.4 l of the synthetic wastewater with 50, 100, 200, and 500 mg/l ${NH_4}^+$-N, respectively, and 1.0 mg from the real wastewater with 125 mg/l ${NH_4}^+$-N. The results indicate that $N_2O$ emission increased with ammonium concentration and the load. The ammonium removal rate and nitrite concentration also increased $N_2O$ emission. Comparative analysis of $N_2O$ emission from synthetic and real wastewaters revealed that wastewater nitrification under oxygen-limited condition emitted more $N_2O$ than that of heterotrophic denitrification. Summarizing the results, it can be concluded that denitrification by autotrophic nitrifiers contributes significantly to the $N_2O$ emission from wastewater nitrification.

• 한국결정성장학회지
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• 제6권1호
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• pp.1-10
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• 1996

초크랄스키법에 의한 8언치 실리콘 단결정 성장시 커스프자장의 영향에 관한 수치 해석적 연구를 행하였다. 액상실리콘의 유동에 대한 모렐은 저레이놀즈수 모렐을 사용하였다. 대칭커스프자장은 유션의 강도를 감쇄하였고, 특히 도가니 벽면 근처에서의 유동의 감쇄효과가 현저하였다. 결정으로 혼업되는 산소의 농도는 인가되는 커스프자장의 증가에 따라 감소하였다. 그리고, 결정으로 혼업되는 산소농도의 균일성은 향상되었다. 비대칭커스프 자장은 결정으로 혼 입되는 산소의 농도를 중가시켰지만, 반경방향의 산소농도의 분포는 일정하게 유지되었다. 대칭 과 비대청 커스프자장의 적절한 조합을 행하면 축방향으로 일정한 산소의 분포를 갖는 적절한 조업조건이 도출될 것으로 예상된다.

• 한국산업융합학회 논문집
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• 제4권1호
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• pp.61-69
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• 2001

Polycarbonate(PC) membranes for oxygen enrichment from air were prepared by the wet phase inversion method. In order to improve oxygen separation performances of the PC membrane, the effect of the added ethanol(nonsolvent) and $CuCl_2$(metal salt) concentration in the casting solution on morphology, oxygen permeability ami $O_2/N_2$ separation factor of the membrane was studied. In addition, tensile strength and elongation at break of the membrane were investigated. An asymmetric membrane with a dense top layer and a porous sublayer was obtained. The thickness of the dense top layer decreased with increasing amount of nonsolvent additive. Compared with pure PC membrane without additive(metal salt), the oxygen permeability and $O_2/N_2$ separation factor of the $PC/CuCl_2$ membrane are significantly improved. The oxygen permeability and $O_2/N_2$ separation factor is $5.25{\times}10^{-9}cm^3(STP){\cdot}cm/cm^2{\cdot}sec{\cdot}cmHg$ and 4.5, respectively. This improvement might be due to good interaction between metal salt and oxygen.

• 한국수소및신에너지학회논문집
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• 제20권3호
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• pp.245-255
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• 2009

Effect of CO$_2$ concentration on reduction reactivity of oxygen carrier particles for chemical-looping combustor were investigated. Four particles, NiO/bentonite, OCN601-650, OCN702-1100, OCN702-1250, were used as oxygen carrier particles and two kinds of gases (CH$_4$, 5%, N$_2$ balance and CH$_4$ 5%, CO$_2$ balance) were used as reactants for reduction. For all oxygen carrier particles, higher maximum conversion, reduction rate, oxygen transfer capacity, and oxygen transfer rate were achieved when we used N$_2$ balance gas. OCN601-650 particle showed higher oxygen transfer rate for all gases than other particles, and therefore we selected OCN601-650 particle as the best candidate. For all particles, lower carbon depositions were observed when we used CO$_2$ balance gas.

• 조명전기설비학회논문지
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• 제29권3호
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• pp.54-60
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• 2015

There are 5 purification plants with the adopted advanced water purification treatment process in Korea. Annual operating costs were 8,990 million won including purchase cost of oxygen and power usage charges. We need research to optimize, in the future, when considering the direction of domestic water treatment continues to adopt advanced water treatment process. In this paper, calculate the optimal operating costs by injected the oxygen gas, used power cost. approximately 25% of the operating costs can be reduced when injected the ozone gas is 1.0ppm than 2.0ppm, the necessary amount of oxygen is increased then power is lower. so operating costs are decided according to oxygen costs. On the other hand, high ozone concentration 2.0ppm, the necessary power is increased then amount of oxygen is lower. Therefore, in the case of G purification plant, the controlling factor of the input ozone concentration 2ppm, PID control operation by setting the concentration of over 10Wt% is efficient. The installed capacity is the more little the more better when considering on Ozone injection rate in the process of water treatment.

• 한국산학기술학회논문지
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• 제13권6호
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• pp.2479-2483
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• 2012

본 논문은 휴대 및 이동이 가능한 개인용 소형 산소발생기 개발에 관한 것이다. 소형 산소발생기는 소형 진공펌프에 의해 진공흡착방식으로 작동된다. 각 구성품을 소형화와 경량화에 맞춰 구성하였으며 토출펌프 회전속도, 노즐 직경, 3-way 밸브 작동시간을 변화시키면서 산소농도와 유량을 최적화하였다. 노즐 직경 0.5mm에서 발생된 산소농도는 약 37%이며 유량은 $1{\ell}$/min이다. 노즐로부터 30cm 떨어진 위치에서 약 0.5%의 농도증가 효과가 나타났다.

• 한국기계가공학회지
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• 제16권3호
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• pp.88-93
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• 2017

In the present study, the ignition characteristics of liquid fuel were experimentally investigated. To quantify its ignitability as ignition characteristics, the minimum ignition energy (MIE) of liquid fuel was defined and measured under at the elevated oxygen concentrations and reduced atmospheric pressures which that are the most probable conditions likely to be encountered during operation of the space launch vehicle's operating process. The experimental results demonstrate that the measured MIE decreased with the increasing the oxygen concentration at given atmospheric pressures. When the atmospheric pressure was reduced from 1 atm to 0.2 atm at a fixed oxygen concentration, the measured MIE was found to vary with $P^{-2}$ but the lowest MIE was observed at 0.8 atm.

• JSTS:Journal of Semiconductor Technology and Science
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• 제3권2호
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• pp.96-101
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• 2003

Direct evidence on the incorporation of high concentration of oxygen into undoped AlGaN layers for the AlGaN/GaN heterostuctures is provided by scanning photoemission microscopy using synchrotron radiation. In-situ annealing at $1000^{\circ}C$ resulted in a significant increase in the oxygen concentration at the AlGaN surface due to the predominant formation of Al-O bonds. The oxygen incorporation into the AlGaN layers resulting from the high reactivity of Al to oxygen can enhance the tunneling-assisted transport of electrons at the metal/AlGaN interface, leading to the reduction of the Schottky barrier height and the increase of the sheet carrier concentration near the AlGaN/GaN interface.