• Korean Journal of Materials Research
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• v.8 no.1
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• pp.71-79
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• 1998

RTCVD법으로 증착된 다결정 Si$_{1-x}$Ge$_{x}$박막에서 Ge조성 증가에 따른 결정립크기변화가 표면거칠기 및 cluster크기에 미치는 영향에 대해 알아본결과, Ge조성 증가에 따라 결정립크기가 증가했으며 증가된 결정립에 의해 Cluster 크기와 표면거칠기값(RMS)들이 증가함을 알 수 있었다. 또한 증착된 다결정 Si$_{1-x}$Ge$_{x}$박막을 RF power와 온도변화에 따라 Ar/H$_{2}$플라즈마를 이용한 수소화처리를 행하여, 수소화 효과와 표면거칠기값 그리고 비저항값 변화에 대해 조사하였다. 수소화처리 후 cluster크기와 표면거칠기값은 기판온도와 RF power 증가에따라 감소함을 알 수 있었으며 특히 기판온도 30$0^{\circ}C$에서는 비저항값이 상당히 증가하였다.

• Applied Chemistry for Engineering
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• v.19 no.4
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• pp.432-438
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• 2008

Hydrogenation reactions of p-toluidine over Ru/C were performed while varying reaction temperature, the hydrogen pressure, catalyst loading, solvent, and alkali additive and the effects on the reaction rates and product distribution were examined. 4-Methylcyclohexylamine was generated as a main product and bis(4-methyl cyclohexyl)amine was obtained as a resentative side-product for the hydrogenation reaction of p-toluidine. The selectivity of MCHA decreased with reaction temperature and the hydrogen pressure while increased with catalyst loading. IPA was the best solvent for MCHA. A mechanism of hydrogenation reaction of p-toluidine was suggested from the results. It was found that the presence of alkali salt increased MCHA by reducing BMCHA and rates of hydrogen reaction increased.

• Proceedings of the Korean Vacuum Society Conference
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• 2014.02a
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• pp.489.1-489.1
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• 2014

Plasma Enhanced Chemical Vapor Deposition (PECVD) 장치를 통하여 증착된 수소화된 질화막(SiNx:H)은 결정질 태양전지의 반사방지막과 패시베이션 층으로 널리 사용되고 있다. 본 연구에서는 PECVD 장치내에 플라즈마를 형성하는 무선주파수(Radio Frequency)를 다양하게 변화시켜 수소화된 실리콘 질화막의 경향성을 알아보고 각 무선주파수에서 최적화된 패시베이션층을 태양전지에 적용하여 그 특성들을 분석하였다. 다양한 무선주파수 범위는 고주파(High Frequency: 13.56 MHz), 저주파 (Low Frequency: 440 kHZ) 그리고 혼합주파(Dual Frequency: 13.56 MHz + 440 kHz)를 각각 이용하여 수소화된 질화막을 증착 하였으며 $156{\times}156mm$ 대면적 결정질 실리콘 태양전지를 제작하여 비교하였다.

• Resources Recycling
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• v.10 no.3
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• pp.60-65
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• 2001

The PVC powder was treated at $200~250^{\circ}C$, in 0~2 M NaOH solutions for 0~5 h to study the kinetics of dehydrochlorination. In the case of water, the dehydrochlorination of PVC powder proceeded by the zero order reaction with X(the degree of dehydrochlorination), and the apparent activation energy was about 46 kcal/mol. The rate of dehydrochlorination increased with con-centration to 0.5 M NaOH, and proceeded by the first order reaction with X. And, the kinetics of dehydrochlorination was almost equal above 0.5 M NaOH. The apparent activation energies of dehydrochlorination in 0.1 M and 0.5 M NaOH was about 46 kcal/mol, respectively.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.36 no.1
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• pp.75-81
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• 2012

Autoignited lifted flames in laminar jets with hydrogen-enriched methane fuels have been investigated experimentally in heated coflow air. The results showed that the autoignited lifted flame of the methane/hydrogen mixture, which had an initial temperature over 920 K, the threshold temperature for autoignition in methane jets, exhibited features typical of either a tribrachial edge or mild combustion depending on fuel mole fraction and the liftoff height increased with jet velocity. The liftoff height in the hydrogen-assisted autoignition regime was dependent on the square of the adiabatic ignition delay time for the addition of small amounts of hydrogen, as was the case for pure methane jets. When the initial temperature was below 920 K, where the methane fuel did not show autoignition behavior, the flame was autoignited by the addition of hydrogen, which is an ignition improver. The liftoff height demonstrated a unique feature in that it decreased nonlinearly as the jet velocity increased. The differential diffusion of hydrogen is expected to play a crucial role in the decrease in the liftoff height with increasing jet velocity.

• Korean Chemical Engineering Research
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• v.45 no.3
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• pp.219-225
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• 2007

The equilibrium solubilization capacity of pure hydrocarbon oils by 2.5 wt% $C_{12}E_8$ nonionic surfactant solution was measured at $30^{\circ}C$ by gas chromatography (GC) analysis. Experimental results indicated that the molar solubilization ratio (MSR) for pure alkanes was found to decrease almost linearly with the alkane carbon number (ACN) of the hydrocarbon oil. For the binary mixture systems of the hydrocarbon oils both selective and nonselective solubilization behaviors were observed depending on the difference in carbon number of the two hydrocarbon oils. Equilibrium solubilization tests for the two n-octane/n-nonane and n-nonane/n-decane mixture systems in $C_{12}E_8$ surfactant solutions suggest slightly selective solubilization in favor of n-octane, but the small difference in solubilization rates between two hydrocarbon oils does not allow ruling out non-selective solubilization for these particular systems. This is certainly not the case for the n-octane/n-decane mixture, for which selective solubilization was conclusively demonstrated by GC analysis data.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.255-260
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• 1998

Metal hydrides, $LaNi_5$ and $LaNi_{4.5}Al_{0.5}$, were prepared using chemical synthetic method, and their physical properties were examined using various analytic techniques such as TGA, XRD, SEM and EDX. The activation of the chemically prepared $LaNi_5$ and $LaNi_{4.5}Al_{0.5}$ was achieved by two hydriding/dehydriding cycles only. The miasurements of P-C-T curves revealed that 6 and 5.5 hydrogen atoms were stored in LaNi5and $LaNi_{4.5}Al_{0.5}$, respectively. The hydriding reaction rated for $LaNi_{4.5}Al_{0.5}$ were measured by the method of initial rates. It was found that the shrinking unreacted core model could be applied for the analysis of hydriding kinetics of $LaNi_5$. The rate controlling step of this reaction was the dissociative chemisorption of hydrogen molecules on the surface of $LaNi_5$. The activation energy was $9.506kcal/mol-H_2$. The rates measured in the temperature range from 273 to 343K and in pressure difference ($P_o-P_{eq}$) range form 0.25 to 0.66atm could be expressed as the following equation ; $\frac{dX}{dt}=4.636(P_o-P_{eq})$ exp($\frac{-9506}{RT}$).

• Membrane Journal
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• v.21 no.3
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• pp.290-298
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• 2011

The influence of co-existing gases on the hydrogen permeation was studied through a Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane. The hydrogen permeation characteristics of Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane have been investigated in the pressure range 1-3 bar under pure hydrogen and hydrogen mixture gas with carbon dioxide and carbon monoxide at $450^{\circ}C$. Preliminary hydrogen permeation experiments have been confirmed that hydrogen flux was $5.36mL/min/cm^2$ for a Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane (thick: 0.5 mm) using pure hydrogen as the feed gas. In addition, hydrogen fluxes were 4.46, 5.20, $3.91mL /min/cm^2$ for$V_{53}Ti_{26}Ni_{21}$ alloy membrane using $H_2/CO_2$, $H_2/CO$ and $H_2/CO_2/CO$ as the feed gas respectively. Therefore, the hydrogen permeation flux decreased with decrease of hydrogen partial pressure irrespective of temperature and pressure when $H_2/CO_2$, $H_2/CO$ and $H_2/CO_2/CO$ mixture applied as feed gas respectively and permeation fluxes were satisfied with Sievert's law in different feed conditions. It was found from XRD results after permeation test that the Pd-coated $V_{53}Ti_{26}Ni_{21}$ alloy membrane had good stability and durability for various mixtures feeding condition.

• 한국전기화학회:학술대회논문집
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• 2004.04a
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• pp.56-56
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• 2004

• Journal of the Korean Institute of Gas
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• v.27 no.1
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• pp.1-12
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• 2023

Coal gasification is a process of incomplete coal combustion to produce a syngas composed of hydrogen and carbon monoxide. It is one of methods to utilize coal cleanly because the process does not emits nitrogen oxides or sulfur oxides and particulate matters. In addition, chemicals can be produced using syngas. Coal gasification is classified as IGCC (Integrated Gasification Combined Cycle), Plasma coal gasification and UCG (Underground Coal Gasification). Recently, WGS (Water Gas Shift) reactor and carbon capture system have been combined to gasifier to produce hydrogen from coal. In this study, the coal gasification and method of hydrogen production from syngas was summarized, and the hydrogen production from coal gasification project was investigated.