• Membrane Journal
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• v.21 no.4
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• pp.367-376
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• 2011

Huge amount of $CH_4$ mixtures has been emitted from landfills and organic wastes via anaerobic digestion. The recovery of high purity $CH_4$ from these gases has two merits: reduction of green house gases and production of renewable fuels. Membrane technology based on polymeric materials can be used in this application. In this study, asymmetric gas separation hollow fiber membranes were fabricated to develop the membrane-based bio-gas purification process. Polyethersulfone (PES) was chosen as a polymer materials because of high $CO_2$ permeability of 3.4 barrer and $CO_2/CH_4$ selectivity of 50[1]. Acetone was used as a non-solvent additive because of its unique swelling power for PES and highly volatile character. The prepared PES hollow fiber showed excellent separation properties: 36 GPU of $CO_2$ permeance and 46 of $CO_2/CH_4$ selectivity at optimized preparation conditions: 9wt% acetone content, 10cm air-gap and 4wt% PDMS coating processes. With the PES hollow fiber membranes developed, mixed $CO_2/CH_4$ test was done by changing various operating conditions such as pressures and feed compositions to meet the highest recovery of CH4 with 95% purity. High $CH_4$ recovery of 58 wt% was observed at 10 atm feed pressure for the 50 vol% of $CO_2$ in $CO_2/CH_4$ mixture.

• Korean Journal of Food Science and Technology
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• v.53 no.5
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• pp.634-639
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• 2021

This study investigated the effects of cold plasma (CP) treatment on the properties of biopolymer films prepared with defatted mustard meal (DMM films). CP treatments using N₂, O₂, He, Ar, and dry air did not affect the tensile properties, water vapor permeability, color, and morphology of DMM films, whereas the treatments using He and Ar improved their printability. The tensile strength (TS) of O₂- or air-CP-treated DMM films and the elastic modulus (EM) of O₂-, He-, Ar-, or air-CP-treated films were lower than those of the untreated films. An increase in the power of Ar-CP treatment resulted in an increase in EM. The optimum treatment power and time for minimizing yellowness changes by Ar-CP treatment were 420 W and 40 min, respectively. The results demonstrated the potential application of CP treatment to improve the film properties of DMM films and possibly other agricultural by-product-based biopolymer films, making the films more applicable to food packaging.

• Journal of Korean Society of Environmental Engineers
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• v.22 no.7
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• pp.1233-1241
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• 2000

The purpose of this study is to see the remediability and pilot system operating condition on diesel contaminated areas. Air permeability(k) and trend of gas phase ($O_2/CO_2/VOCs$) concentration to determine the remediation rate of the contaminated sites are very important. So we tested air permeability and trend of gas phase concentration. Throughout soil vapor extraction(SVE) and bioventing hybrid pilot test on different conditions, the range of air permeability(k) was 1985~1194 darcy. The tests result in soil vapor extraction and bioventing hybrid system was appropriate on this test sites, and the suitable injection air flow rate was $3.5m^3/hr$.

• 한국신재생에너지학회:학술대회논문집
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• 2009.11a
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• pp.382-382
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• 2009

염료감응형 태양전지의 구성체 중 전극으로 연구 되어 지고 있는 $TiO_2$는 기존에 대량 생산이 가능한 spin coating법, screen printing법, spray법의 연구가 이루어져 왔으나 고 효율 태양전지에 쓰이는 전극 시스템에 비해 고 분산성을 지닌 $TiO_2$페이스트를 제조 하는데 어려움이 있다. 그리고 플렉시블 디스플레이 소자의 응용을 위해서는 소자 공정 온도인 $250^{\circ}C$ 이하의 공정 온도가 요구 되어 지므로 고온공정인 CVD법은 이에 적합하지 않다. 이에 본 연구는 진공 증착 방법인 광원자층증착법을 이용하여 $150^{\circ}C$이하의 저온공정온도에서도 적용이 가능한 $TiO_2$ 박막을 185nm의 UV light를 조사하여 glass 기판위에 제조 하고 그에 따른 박막의 물성 분석을 하였다. Mo source로는 titanium tetraisopropoxide(TTIP)와 reactant gas 로는 $H_2O$를 사용하였으며 불활성 기체인 Ar 가스는 purge 가스로 각각 사용하였다. $100^{\circ}C{\sim}250^{\circ}C$ 공정온도를 변수로 $TiO_2$ 박막을 제조 하였으며 제조된 $TiO_2$ 박막의 물성 분석을 위해 FESEM, TEM을 이용하여 표면 및 두께를 분석하였다. 또한 $100^{\circ}C$ 400 cycles에서 약 12nm 막 두께를 관찰 할 수 있었으며 그 결과 박막의 성장률이 $0.3{\AA}$/cycle 임을 확인 할 수 있었다. 그리고 UV-VIS을 이용하여 박막의 좌외선에 대한 흡수도 및 투과도 분석을 하였다. 또한 XPS 성분 분석을 통하여 $100^{\circ}C$의 저온 공정에서 형성된 박막이 $TiO_2$임을 확인 하였다. 이러한 결과에서 185nm의 UV light에 의한 광원자층 증착법으로 $100^{\circ}C$의 저온에서도 $TiO_2$ 박막이 증착 되는 것을 확인 할 수 있었다.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.196-196
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• 2011

팔라듐-구리 합금 분리막은 세륨산화물로 전처리된 다공성 니켈 지지체 위에 마그네트론 스퍼터 공정과 구리리플로우 공정에 의해 제조되었다. 스퍼터 공정은 얇고 치밀한 팔라듐 합금 분리막 증착을 위해 아주 효과적이다. 본 연구에서는 고온 스퍼터 공정에 의해 증착된 팔라듐 상부에 유동성과 열적확산이 우수한 구리를 코팅한 후, 반도체 분야에서 기가 패턴 매립시 사용하는 구리리플로우 공정을 도입하였다. 구리리플로우 공정은 치밀하고 미세기공이 존재하지 않는 표면을 구현하고 무한대의 수소 투과도를 가능하게 한다. 이로써 마그네트론 스퍼터에 의해 $200^{\circ}C$에서 팔라듐과 구리를 순차적으로 코팅한 후, $700^{\circ}C$에서 2시간 구리리플로우 공정을 실시하여 $7.5{\mu}m$ 두께의 팔라듐-구리 합금 분리막이 제조되었다. 세륨산화물(CeO2)은 고온에서 장시간 운전하는 동안 다공성 니켈 지지체의 금속성분이 팔라듐 합금층으로 확산하는 금속의 확산 문제를 개선하고자 지지체와 코팅층 사이에 확산방지막으로 도입되었으며, 균일한 스퍼터 증착을 위해 평탄한 표면의 지지체를 구현하였다. 투과도 테스트는 100-400kPa 의 압력차, 673-773K 의 온도 조건에서 순수한 수소가스로 실시하였다. 표면 미세기공이 없는 치밀한 팔라듐-구리 합금 분리막은 혼합가스에서 질소의 투과 없이 수소만을 투과하는 무한대의 우수한 분리도를 나타내었으며, 상용온도 $500^{\circ}C$에서 12.6ml/$cm^2{\cdot}min{\cdot}atm$의 수소 투과 능력을 보였다. 본 연구에 의해 제조된 팔라듐-구리 합금 분리막은 표면 미세기공이 없는 치밀한 분리막 제조를 가능하게 하였으며 열팽창계수가 팔라듐과 매우 비슷한 세륨산화물($CeO_2$)로 인해 지지체층과 코팅층과의 접합력이 향상되고 수소취성에 강하고 높은 열적 안정성을 갖는다.

• Journal of Veterinary Clinics
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• v.20 no.3
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• pp.286-293
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• 2003

The cardiopulmonary and antagonistic effects of atipamezole, to medetomidine (30 ug/kg, IM)-tiletamine/zolazepam (10 mg/kg, IV) were determined. Twelve healthy mongrel dogs ,(4.00$\pm$0.53 kg, mean$\pm$SD) were randomly assigned to the four experimental groups (control, A30; atipamezole 30 ug/kg, A60; atipamezole 60 ug/kg, A150; atipamezole 150 ug/kg) with 3 dogs in each group. Atropine (0.03 mg/kg, IM), medetomidine, and tiletamine/zolazepam (TZ) were injected 10 minute intervals. Atipamezole was injected intravenously 15 minutes after TZ injection. Mean arousal time (MAT) was 52.50$\pm$4.98, 43.06$\pm$2.60, 32.83$\pm$8.13, and 14.36$\pm$1.60 minutes in control, A30, A60, and Al50 groups respectively. In Al50 group, MAT was significantly reduced (P < 0.05). but mean walking time (MWT) was similar to that in control group. In recovery period, the higher doses of atimapezole, the rougher recovery including head rocking, hypersalivation, and muscle twitching. Five of twelve dogs vomited within 5 minutes after medetomidine injection. In Control group, heart rate significantly decreased in all recording stages except 15 minutes after TZ injection, 10 minutes after medetomidine injection in all groups, and 40 minutes after atipamezole injection in A30 group (P < 0.05). In Al50 group, atipamezole reversed the respiratory depression induced by medetomidine. Arterial blood pressure was significantly decreased 10minutes after medetomidine injection and 15 minutes after TZ injection in almost dogs in this study (P < 0.05). From 10 minutes after atipamezole injection to arousal time, arterial blood pressure was progressively increased in A60 and A150 group. Any value of blood gas analysis and CBC, and serum chemistry values were not significantly changed except pH of Al50 at 10 minutes after medetomidine injection. As shown in present study, atipamezole(150 ug/kg) is considered to exert a useful reversal effect in dogs anesthetized with medetomidine-tiletamine/zolazepam combination.

• Korean Journal of Food Science and Technology
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• v.15 no.2
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• pp.202-204
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• 1983

A strategy for the automation of glutamic acid fermentation has been developed by the use of $CO_2$ analyzer together with a controller. It was found that a linear relationship existed between growth and $CO_2$ level in the exit gas. Therefore penicillin addition at an appropriate biomass concentration to excrete glutamate could be achieved automatically. In addition, an automatic batch feeding method (fed-batch culture) provided a means of overcoming substrate inhibition effects on growth and glutamic acid production in batch culture, thereby increasing productivity and product yield.

• Journal of the Korean Geotechnical Society
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• v.16 no.1
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• pp.221-226
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• 2000

In this study, the characteristics of gas-water relative permeability curves in a single fractured-plate according to the various aperture size were analyzed by using the Hele-Shaw type glass plate model. The plate was made of glasses for the observation of the two-phase flow pattern, and seven cases were set up based on the aperture size in the range of field scale from 30 to $120\mum$. The experiment was conducted by steady-state method, and the water saturation was determined more accurately by the developed digital image process technique. The empirical equations of relative permeability to gas and water for single fractured-plate were correlated by using the aperture size which directly affects the two-phase flow pattern and critical saturation.

• YAKHAK HOEJI
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• v.41 no.6
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• pp.698-703
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• 1997

Recently, l-deprenyl (selegiline), a relative new antiparkinson`s drug, has been marketed in Korea. As its metabolites, l-methamphetamine and l-amphetamine, are the enantiomers of illicit drugs,d-methamphetamine and d-amphetamine, a method for analysis of enantiomers of methamphetamine and amphetamine in rat urine was investigated. The optical isomers of methamphetamine and amphetamine were analyzed with the chiral derivatizing reagent (S)-(-)-N-(trifluoroacetyl)-prolyl chloride (l-TFP), which was used to form the diastereomers of methamphetamine and amphetamine. And all diastereomers (l-TFP -l-AM, lTFP-d-AM, l-TFP-l-MA & l-TFP-d-MA) were well resolved by capillary gas chromatography. After administration of 10mg/kg l-deprenyl to rat, l-methamphetamine and l-amphetamine were detected without autoracemization to the d form in all urine samples collected during 24hrs, and the ratios of l-amphetamine/l-methamphetamine were 1.1~3.3. l-Amphetamine was detected in only 3 out of 8 urine samples collected during 24~48hrs where as no l-methamphetamine was detected in all cases.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.178.1-178.1
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• 2013

산화물 반도체는 가시광선영역인 380~780nm에서의 투과율이 80% 이상이고, 3.2eV 이상의 밴드갭과 높은 이동도를 가지는 물질로 투명하고 휘어지는 디스플레이에 전도유망한 물질로 연구되고 있다. $10cm^2/V{\cdot}s$ 이상의 이동도를 확보하기 위해 IGZO에서 Ga대신 Sn을 첨가한 ITZO 산화물 반도체에 대한 연구가 되고 있다. 본 연구에서 ITZO 산화물 반도체 박막 증착 시 가장 중요한 특성으로 알려진 산소의 영향에 따른 광학적 특성을 알아보기 위한 실험이다. RF 마그네트론 스퍼터링을 이용하여 산소 가스 분압에 따라 ITZO 박막을 증착하였다. $(Ar+O_2)$의 합을 20으로 고정하고 $O_2/(Ar+O_2)$의 비율을 0~40%까지 가변하였고, $O_2$의 비율이 증가함에 따라 증착율은 감소하는 경향을 보였다. 투명 소자로서의 가능성을 판단하기 위하여 밴드갭과 투과도를 측정하였다. 광학적 밴드갭은 증착 시 산소 분압이 0%에서 40%로 증가할수록 3.46eV에서 3.32eV로 감소하였고, 또한 투과도가 가시광 영역(380~770nm)에서 87%에서 85% 감소하였다. In, Sn, Zn 의 금속 원자와의 결합 과정에서 산소의 빈자리가 줄어들어 전도도가 감소하여 광학적 밴드갭이 감소함에 따라 투과도가 감소하는 것을 확인하였다.