• 신재생에너지
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• 제2권2호
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• pp.50-59
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• 2006

An experimental and numerical study is carried out to investigate the performance and the efficiency humidifying Membrane Electrolyte Assembly and having the double-layered catalyst in a fuel cell system which is taken into account the physical and thermal concept. Based on the principals of the problem, the equation of electronic charge conservation equation, gas-phase continuity equation, and mass balance equation are used for the numerical calculation. A unit cell for $200cm^2$ MEA is assembled and measured for finding better operational situation. After finding the optimal condition, 10 cell stacked PEMFC is fabricated. For the performance evaluation, V-I and power curves are examined in detail by changing the condition of humidity, temperature, pressure, thickness of catalyst and oxidant. It is found that the power is maximized around 500W at 80A.

• 한국농공학회:학술대회논문집
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• 한국농공학회 2002년도 학술발표회 발표논문집
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• pp.249-252
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• 2002

This model is the daily streamflow model of the Korean watersheds has been developed to simulate the daily streamflow with the data of daily rainfall and pan evaporation. Parameters of this model are the water balance parameters composed Umax, Lmax, FC, CP, and CE and the routing parameters composed $U_i,\;k_1\;and\;k_2$. Among these parameters, CE value is applied one fixed value during the year and coefficient of initial ion K is empirically determined by 0.2. The object of this research is to improve the DAWAST model by application of the monthly value of CE for evapotranspiration and the revised K value for the initial abstraction.

• 한국재료학회지
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• 제12권8호
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• pp.676-681
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• 2002

Microstructure, mechanical properties, and oxidation resistance of TiAIN thin films deposited on quenched and tempered STD61 tool steel by arc ion plating were studied using XRD, XPS and micro-balance. The TiAIN film was grown with the (200) orientation. The grain size of TiAIN thin film decreased with increasing Al contents, while chemical binding energy increased with Al contents. When hard coating films were oxidized at $850^{\circ}C$ in air, oxidation resistance of both TiN and TiCN films became relatively lower since the surface of films formed non-protective film such as $TiO_2$. However, oxidation resistance of TiAIN film was excellent because its surface formed protective layer such as $_A12$$O_3$ and $_Al2$$Ti_{7}$$O_{15}$, which suppressed oxygen intrusion.

• BMB Reports
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• 제44권5호
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• pp.312-316
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• 2011

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) and its toxic metabolite 1-methyl-4-phenylpyridium ion (MPP$^+$) have been shown to induce Parkinson's disease-like symptoms as well as neurotoxicity in humans and animal species. Recently, we reported that maintenance of redox balance and cellular defense against oxidative damage are primary functions of the novel antioxidant enzyme cytosolic NADP$^+$-dependent isocitrate dehydrogenase (IDPc). In this study, we examined the role of IDPc in cellular defense against MPP$^+$-induced oxidative injury using PC12 cells transfected with IDPc small interfering RNA (siRNA). Our results demonstrate that MPP$^+$-mediated disruption of cellular redox status, oxidative damage to cells, and apoptotic cell death were significantly enhanced by knockdown of IDPc.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.51-54
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• 2003

We investigated the quench characteristics of thin film type SFCLs with shunt layers of various thickness. The SFCLs ware based on 2 inch diameter YBa$_2$Cu$_3$O$_{7}$ thin films coated in-situ with a gold shunt layer. The shunt layer thickness was varied by Ar ion milling. The limiters were tested with simulated fault currents at various source voltages. The thinner the shunt layer was, the slower was the rise of SFCL temperatures. This means SFCLs of thinner shunt layers had higher voltage ratings. The voltage rating was approximately inversely proportional to the square root of the shunt layer thickness. This result could be understood through the concept of heat balance.e.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2003년도 학술대회 논문집
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• pp.242-245
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• 2003

We investigated the quench characteristics of thin film type SFCLs with shunt layers of various thickness. The SFCLs ware based on 2 inch diameter YBa$_2$Cu$_3$3O$_{7}$ thin films coated in-situ with a gold shunt layer. The shunt layer thickness was varied by Ar ion milling. The limiters were tested with simulated fault currents at various source voltages. The thinner the shunt layer was, the slower was the rise of SFCL temperatures. This means SFCLs of thinner shunt layers had higher voltage ratings. The voltage rating was approximately inversely proportional to the square root of the shunt layer thickness. This result could be understood through the concept of heat balance.e.

• 대한화학회지
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• 제13권4호
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• pp.309-312
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• 1969

A series of metal ion-2, 5-diamine 1, 4-dihydroxybenzene polymers containing copper(II), nickel(II) or cobalt (II) have been prepared. The structure was postulated on the basis of elementary analysis of polymers. It was found that copper polymer is most likely the coordination polymers by X-ray powder pattern studies. The thermal stability of the polymers was also studied by a simple method, utilizing a thermogravimetric balance. The order of thermal stabilities is Cu(II) > Ni(II) > Co(II). The polymers start to decompose at a relatively low temperature.

• 한국대기환경학회지
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• 제19권3호
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• pp.333-343
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• 2003

The aerosol ionic composition of P $M_{2.5}$ measured at Gosan, Jeju Island, Korea, for 4 years between March 1998 and February 2002 are presented and discussed. The annual mean concentration of non- sea-salt sulfate (nss -S $O_4$$^{2-}$) and ammonium (N $H_4$$^{+}$) ions are high (0.094 $\mu$eq/㎥, and 0.085 $\mu$eq/㎥, respectively). Also, nss-S $O_4$$^{2-}$ and N $H_4$$^{+}$ show high correlation (0.892). The concentrations of most ions are high in springtime. As the result of factor analysis, Gosan area mainly affected by sea-salt, anthropogenic species, and crustal species.ies.

• 한국농림기상학회지
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• 제9권2호
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• pp.75-87
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• 2007

광릉 슈퍼사이트 내 원두부 소유역에서 지하수위변동법, 이온수지법, 수문곡선분리법 등 세가지 방법을 적용하여 지하수 함양률을 평가하고, 방법별 결과들을 비교하였다. 이를 위한 자료는 우기에 해당하는 2005년 6월부터 9월까지 취득하였다. 두 가지 다른 지하수위변동법으로는 각각 25.9%, 23.6%의 지하수 함양률이 산출되었고, 염소를 이용한 이온수지법은 평균 13.4%의 함양률이, 그리고 6개의 수문곡선과 염소 이온자료를 이용한 기저유출 분리법은 평균 14.0%의 순기저유출률이 산출되었다. 장기적으로 지하수 저장량의 변화가 없는 정류상태를 가정하는 이온수지법과 수문곡선 분리법에서 산출된 지하수 함양률이 지하수 함양으로 인해 지하수위의 상승과 저장량의 변화를 고려하는 지하수위변동법에서 산출된 지하수 함양률보다 작게 산정되었다. 따라서 수문순환의 동력학적 특성을 이해하는 측면에서는, 지하수위변동법에 의한 지하수 함양률 평가가 다른 방법들보다 우월함을 보인다.

• 한국환경농학회지
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• 제18권2호
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• pp.169-173
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• 1999

경기 남부지역 빗물의 화학적 특성을 알아보기 위하여 1998년 5월부터 10월까지 6개월 동안 수원과 안성지역에 내린 빗물을 채취하여 화학성분을 분석하였으며, 분석결과에 대한 신뢰성을 검토한 결과는 다음과 같다. 각 분석시료에 대한 양이온과 음이온의 균형과 전기전도도의 이론치와 실측치간의 관계를 조사한 결과, 고농도 시료를 제외하고는 분석의 신뢰성이 인정되었다. 조사기간중 빗물의 pH 분포는 수원과 안성지역 모두 pH $5.0{\sim}5.6$ 범위에서 각각 37.9%, 35.3%로 가장 많았으며, 강우량별 빗물의 이온함량과 pH 변화는 초기빗물(1mm 이하)가 그 이후의 빗물에 비해 높았다. 빗물의 조성은 $SO_4^{2-}$와 $NO_3^-$가 음이온의 약 85% 그리고 양이온은 $NH_4^-,\;Ca^{2+}$ 및 $Na^+$가 약 80%를 차지하고 있다. 월별 빗물의 pH는 8월과 9월에 수원지역은 4.5와 4.2 그리고 안성지역은 4.6과 4.7로 그외 조사시기 보다 낮았고 조사지역 빗물중 비해염(非海鹽) sulfate는 두 지역 모두 총sulfate 함량의 약 97%이었다. 빗물의 $nss-SO_4^{2-}/NO_3^-$은 평균 수원지역 2.2와 안성지역 빗물 2.9로 비해염 $SO_4^{2-}$에 의한 기여울은 안성지역이 수원지역보다 높았다.