• 멤브레인
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• 제19권1호
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• pp.72-82
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• 2009

A mathematical model was written for simulating the removal of phenol from wastewater in enzyme-loaded membrane reactor (EMR). The numerical simulation program was developed so as to predict the degradation of phenol through an EMR. Numerical model proves to be effective in searching for optimal operating conditions and creating an optimal microenvironment for the biocatalyst in order to optimize productivity. In this study, several dimensionless parameters such as Thiele Modulus (${\phi}^2$, dimensionless Michaelis-Menten constant ($\xi$), Peclet number (Pe) were introduced to simplify their effects on system efficiency. In particular, the study of phenol conversion at different feed compositions shows that low phenol concentrations and high Thiele Modulus values lead to higher reactant degradation.

• Korean Membrane Journal
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• 제8권1호
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• pp.13-20
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• 2006

The production of CO-free hydrogen streams for feeding PEM-Fuel Cells using catalytic zeolite membrane reactors was analysed by means of selective oxidation. Tubular FAU (Na-Y) zeolite membranes, prepared by a secondary growth method and Pt-loaded, were used in a flow-through MR configuration. The catalytic tests were carried out at $200^{\circ}C$ and at different pressures with a simulated dry reformate shifted gas mixture ($H_2$ ca. 60%, CO 1 %, plus $O_2,\;N_2,\;CO_2$). The operative $O_2/CO$ stoichiometric equivalent feed ratio was ${\lambda}= 2$. These catalytic tests, reducing the CO concentration down to $10{\sim}50$ ppm, verified the possibility of MR integration after using a low temperature water-gas shift unit of a fuel processor to convert hydrocarbons into hydrogen-rich gas.

• 한국발생생물학회:학술대회논문집
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• 한국발생생물학회 2005년도 제20차 학술대회 논문집
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• pp.34-34
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• 2005

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.924-927
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• 2003

Aluminium-doped ZnO (ZnO:Al) films were grown by atomic layer-controlled deposition on glass substrates at temperature of 200 $^{\circ}C$ using diethylzinc($Zn(C_{2}H_{2})_{2}$; DEtZn), water($H_{2}O$) and trimethylaluminium ($Al(CH_{3})_{3}$; TMA) as precursors. As the cycle ratio of TMA to DEZn(TMA/DEZn) increased, the resistivity of the films decreased and the roughness increased. In the case of TMA/DEZn pulse ratio of 1 to 10, the film had a resistivity of $9.7{\times}l0^{-4}{\Omega}{\cdot}cm$ and a roughness of 2.25nm(rms), while in the case of only DEZ injection the film had a resistivity of $3.5{\times}10^{-3}{\Omega}{\cdot}cm$ and a roughness of 1.07nm(rms)

• Korean Membrane Journal
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• 제5권1호
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• pp.68-74
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• 2003

Methane steam reforming (MSR) reaction for hydrogen production was studied in a membrane reactor (MR) using two tubular membranes, one Pd-based and one of porous alumina. A higher methane conversion than the thermodynamic equilibrium for a traditional reactor (TR) was achieved using MRs. The experimental temperature range was 350-500$^{\circ}C$; no sweep-gas was employed during reaction tests to avoid its back-permeation through the membrane and the steam/methane molar feed ratio (m) varied in the range 3.5-5.9. The best results (the difference between the MR conversion and the thermodynamic equilibrium was of about 7%) were achieved with the alumina membrane, working with the highest steam/methane ratio and at 450$^{\circ}C$. Silica membranes prepared at KRICT laboratories were characterized with permeation tests on single gases (N$_2$, H$_2$ and CH$_4$). These membranes are suited for H$_2$ separation at high temperature.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.65-68
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• 2003

The paper discusses the use of stable emulsion, prepared by membrane emulsification technology, to improve the enantiocatalytic performance of immobilised lipase in multiphasic membrane reactors. The production of optical pure (S)-naproxen from racemic naproxen methyl ester has been used as model reaction system. The enzyme was immobilised in the sponge layer (shell side) of capillary polyamide membrane with 50 kDa cut-off, The O/W emulsion, containing the substrate in the organic dispersed phase, was fed to the enzyme membrane reactor from shell-to-lumen. The results evidenced that lipase maintained stable activity during all the operation time (more than 250 hours), showing an enantiomeric excess (96 $\pm$2%) comparable to the free enzyme (98 $\pm$ 1%) and much higher compared to similar lipase-loaded membrane reactors used in two-separate phase systems (90%). The study showed that immobilised enzymes can achieve high stability as well as high catalytic activity and enantioselectivity.

• 자원환경지질
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• 제45권2호
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• pp.89-104
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• 2012

본 연구에서는 제주도 토양 중 화산쇄설암과 현무암을 모재로 발달하는 두 Andisol 토양의 Al 용해도 특성을 규명하고자 하였다. 토양 A층은 높은 유기물함량과 $Al_{pyrophosphate}/Al_{oxalate}$ 비를 나타내는 반면, 토양 Bo층은 낮은 유기물함량과 $Al_{pyrophosphate}/Al_{oxalate}$ 비를 나타낸다. 이는 반응성 Al이 A층에서는 대부분이 유기물과 결합한 형태로 존재하고 있는 반면, 토양 Bo층에서는 무기질의 광물과 결합하고 있음을 지시한다. Acid-oxalate 용해처리, 그리고 150 및 $350^{\circ}C$ 열처리 전후의 FT-IR 스펙트럼 비교, 투과전자현미경(TEM)을 이용한 관찰결과, 토양 Bo층에 상당량의 이모골라이트(Imogolite)가 존재함을 확인하였다. 이들 시료에 대한 Al-용해도 특성규명을 위한 Batch 평형실험결과, 토양 Bo층에서의 Al-용해도는 ITM(Imogolite-type material)과 Al hydroxy-interlayered aluminosilicate에 의한 Simultaneous equilibrium보다는 ITM의 Congruent dissolution model을 따르는 것으로 나타났다. 투석과 Aging과정 후의 용해도 특성 변화는 PI(Proto imogolite) sol의 생성이 되고, 이들의 이모골라이트로의 상전이가 Al-용해도에 영향을 주었음을 지시한다. 이러한 결과는, 실내실험 결과를 보완해주는 것으로, 제주도 Andisol토양에서의 Al-용해도 특성이 ITM에 의한 Congruent dissolution에 의해 조절되고 있음을 지시한다.

• 한국막학회:학술대회논문집
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• 한국막학회 2003년도 The 4th Korea-Italy Workshop
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• pp.21-24
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• 2003

Methane steam reforming (MSR) was studied in a membrane reactor (MR) with a Pd-based and a porous alumina membranes. MRs showed methane conversion higher than that foresaw by the thermodynamic equilibrium for a traditional reactor (TR). Silica membranes prepared at KRICT were characterized with permeation tests on single gases ($N_2$, $H_2$ and $CH_4$). These silica membranes can be also used for high temperature applications such as $H_2$ separation $CO_2$ hydrogenation for methanol production is another reaction where $H_2O$ selective removal can be performed with these silica membranes.

• 지역연구
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• 제34권4호
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• pp.61-74
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• 2018

본 연구의 목적은 스마트시티 산업의 융합변화를 분석하는 것이다. 스마트시티의 연관 산업은 정보통신기술 및 지식 기반의 건설 산업으로 정의할 수 있다. 본 연구는 1980년, 2014년 한국은행에서 발표한 산업연관표를 이용하여 투입산출분석과 구조경로분석을 수행하였다. 산업연관표 자료는 2개년도 비교분석을 위해 국내총생산 가격수정인자(GDP Deflator)가 적용되었다. 산업의 분류는 403개 산업을 기준으로 27개 그리고 8개 산업으로 분류되었다. 분석 결과는 다음과 같다. 첫째, 투입산출계수 분석에 따르면, 정보통신 서비스 산업(ITS)과 에너지 공급 산업(EnS)은 건설 산업에 투입량이 증가되었다. 반면에 지식 서비스 산업(KS)과 기타 서비스 산업(EtS)은 감소하였다. 둘째, 생산유발계수 분석 결과, 건설 산업(C)은 정보통신 서비스 산업(ITS), 에너지 공급 산업(EnS), IT 제조 산업(ITM) 그리고 비 IT 제조 산업(NITM) 순으로 직 간접적인 영향을 미쳤으며, 가장 큰 변화량을 보인 산업은 정보통신 서비스 산업(ITS)으로 분석되었다. 셋째, 구조경로분석 결과, 스마트시티 산업은 117개의 새로운 생산경로를 만들었으며, 구조적 세분화를 이끌어내고 있었다. 산업의 융합변화는 정보통신 서비스 산업(ITS), 에너지 공급 산업(EnS), 비 IT 제조업(NITM), IT 제조업(ITM)을 중심으로 진행되고 있었다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.45-49
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• 2001

We have investigated physical and electrical properties of the Hf $O_2$/HfS $i_{x}$/ $O_{y}$ thin film for alternative gate dielectrics in the metal-oxide-semiconductor device. The oxidation of Hf deposited directly on the Si substrate results in the H $f_{x}$/ $O_{y}$ interfacial layer and the high-k Hf $O_2$film simultaneously. Interestingly, the post-oxidation N2 annealing of the H102/H1Si70y thin films reduces(increases) the thickness of an amorphous HfS $i_{x}$/ $O_{y}$ layer(Hf $O_2$ layer). This phenomenon causes the increase of the effective dielectric constant, while maintaining the excellent interfacial properties. The hysteresis window in C-V curves and the midgap interface state density( $D_{itm}$) of Hf $O_2$/HfS $i_{x}$/ $O_{y}$ thin films less than 10 mV and ~3$\times$10$^{11}$ c $m^{-2}$ -eV without post-metallization annealing, respectively. The leakage current was also low (1$\times$10-s A/c $m^2$ at $V_{g}$ = +2 V). It is believed that these excellent results were obtained due to existence of the amorphous HfS $i_{x}$/ $O_{y}$ buffer layer. We also investigated the charge trapping characteristics using Fowler-Nordheim electron injection: We found that the degradation of Hf $O_2$/HfS $i_{x}$/ $O_{y}$ gate oxides is more severe when electrons were injected from the gate electrode.e electrode.e.e electrode.e.