• Journal of the Korean Society of Clothing and Textiles
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• v.22 no.7
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• pp.843-850
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• 1998

The purpose of this study is the investigation of chemical properties of wool treated with oxidants and protease at low temperature. The chemical degradation of the fibers were investigated by measuring $\alpha$-amimo acid contents and FT-IR analysis. In addition, urea-hydrogensulfite solubility was measured to compare to the oxidation and protease treated wool. The results were as follows. 1) By the oxidation of wool, cystine is oxidised to cysteic acid by way of the intermediate oxides, cystine-S-monooxide and cystine-S-dioxide, in the case hydrolysis catalysed by the protease catalyse. Also, $\alpha$-amimo acid contents is increased, and urea-hydrogensulfite solubility was lower than that of untreated wool. This chemical degradation of wool was occurred due to oxidate hydrolysis in the order of permonosulfate>dichloroisocyanuric acid$\geq$chlorine. 2) The chemical degradation of wool was accelerated by the protease treatment of oxidized wool. Oxidation of wool is considered to make the fiber more susceptibled to enzymatic attact by opening disulphide bond within wool. Enzymatic attact was effectively directed to the wool oxidised by permonosulfate.

• Journal of Korea Foundry Society
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• v.18 no.4
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• pp.389-397
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• 1998

회주철 모재의 표면에 감압 플라즈마 용사법으로 실리콘 분말을 피복시킨 후 $CO_2$ 레이저를 이용하는 표면 합금화로 고온 내스케일성이 향상된 표면 개질층을 제조하였다. 실리콘의 표면 합금층에는 응집상의 흑연(chunky graphite)이 $Fe_5Si_3$로 구성된 망상의 화합물 기지속에 정출하는 조직특성을 보였다. 대기 분위기에서 18.0ks동안 열중량측정(TG)한 결과 실리콘 표면 합금층의 무게 증가율은 회주철 모재에 비하여 923K에서는 약 1/3, 1098K에서는 약 1/10을 나타내었다. 그리고 1098K에서 18.0ks동안 유지시킨 주철모재 시편에서 원래의 모재표면을 기준으로 다공성의 외부스케일과 편상흑연을 따라 생성된 내부스케일로 구성된 두께 $60{\sim}70\;{\mu}m$의 두꺼운 산화스케일이 생성되었으나, 실리콘의 표면 합금층에서는 두께 $3{\sim}5\;{\mu}m$의 치밀한 외부 산화스케일만이 생성되었다. 실리콘 합금층의 단면 미소경도값은 MHV $300{\sim}1100$으로 그 변동폭이 심하였으나, 진공분위기에서 열처리(1223K, 18.0ks)한 경우 미소경도값의 편차는 MHV $300{\sim}500$으로 개선되었다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 1999.10a
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• pp.103-106
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• 1999

본 연구에서는 펜톤산화반응에서 과산화수소의 분해촉매로 일반적으로 쓰이는 Fe(II) 형태의 철염대신 Fe$^{\circ}$형태의 분말 철을 이용한 펜톤유사반응(Fenton-like oxidation)에 의한 매립지 침출수(sCODcr 1,100 mg/L, pH 8)의 CODcr 제거특성에 관한 회분식 처리실험을 수행하였다. 실험조건으로는 상온, 상압조건에서 Jar tester를 사용하여 분말 철의 주입 량과 산 세척도, 초기 반응 pH, 과산화수소의 주입 량을 변화시켜가며 침출수의 CODcr 제거효율 의 변화를 관찰하였으며, 이때 과산화수소의 분해 특성과 반응 중 pH의 변화도 함께 분석하였다. 반응은 모든 조건에서 대부분 약 30분 이내에 종료되었으며 그 이후의 반응변화는 미미하였다. 산 세척에 의한 분말 철 표면의 개질로 반응성의 향상을 관찰할 수 있었으며, 분말 철 주입 량을 증가함에 따라 반응속도가 일정하게 증가함을 알 수 있었다. 본 연구에 서 CODcr의 제거 효율에 가장 큰 영향을 보여준 실험변수는 pH 였으며, 원수의 pH(8)를 2-4까지 조절하여 반응을 시켰을 때 최대 75%의 CODcr 제거효율을 얻을 수 있었다. 반응중 pH는 모든 조건에서 시간에 따라 증가하여 약 pH 9에서 더 이상 변화하지 않았다. 용액내 과산화수소의 잔류농도의 곡선은 반응 중 CODcr의 곡선과 유사한 변화를 나타내었다.

• 한국신재생에너지학회:학술대회논문집
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• 2011.11a
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• pp.91.1-91.1
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• 2011

고체산화물 연료전지(Solid Oxide Fuel Cell이하 SOFC)는 연료가 갖는 화학에너지를 연소과정 없이, 공기와 H2, CO, CH4와 같은 환원성 가스를 공급받아 $600{\sim}1000^{\circ}C$에서 전기화학적 반응을 통하여 직접 전기를 얻는 방식이다. SOFC는 $700^{\circ}C$ 이상의 고온에서 고체산화물이 연료와 공기가 반응하여 전기와 열을 동시에 생산하기 때문에 carnot cycle의 제한을 받지 않아 발전효율이 40% 이상으로 고효율이고, NOx 및 SOx를 배출하지 않아 무공해이며, moving parts가 없어 소음이 나지 않고, 건설과 증설이 지역이나 기후 조건에 제약 없이 용이하고, 다양한 용량이 가능하며, 고가의 백금 촉매를 사용하지 않으며, 수소, 석탄가스, 천연가스 등의 연료를 사용할 수 있는 장점이 있음, 또한 다향한 형태로 제작할 수 있으며 전해질이 고체에서 전해질 손실 및 보충에 문제가 없고 타 연료전지에 비해 개질기가 필요 없어 발전시스템이 간단하고 경량화가 가능하다. 전사법은 paste를 제작하여 전사용지에 Screen printing하여 건조 후 coating하는 방법으로 기존의 여러 coating 방법보다 제작이 용이하고 소재의 크기, 두께조절이 간편하며, 구성층의 표면조도나 굴곡에 대응이 용이한 방법이다. 본 실험에서는 paste 제조, 전사법을 이용하여 Anode, AFL, Electrolyte, CFL, Cathode전사지를 제작하고 이를 세라믹 평관형 지지체에 변수로 두께 조건별 Coating 한 후 $1400^{\circ}C$ 소결을 진행하여 SEM 분석으로 미세구조 관찰, 출력특성 및 Impedance을 확인하였다.

• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2144-2148
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• 2008

Kerosene-driven solid oxide fuel cell (SOFC) system with reformer, desulfurizer and after-burner was mainly developed for this study. Originally the system was developed for 1kW class SOFC system for residential power generation (RPG) application. As a preliminary study of 1kW class SOFC system operation, a short stack was applied to the system. The short stack consists of 7 cells of $10cm{\times}10cm$ area and was operated at $720^{\circ}C$. The effect of anode inlet gas composition to stack performance was investigated. Firstly, I-V characteristics of SOFC with different fuel of kerosene and hydrogen were studied. Secondly $CH_4$ internal reforming was performed at various anode inlet gas compositions of $H_2$, $CH_4$ and $H_2O$. Through these experiments the effects of each anode inlet gas component to stack performance were analyzed and the significant operating parameters were iscussed.

• Elastomers and Composites
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• v.37 no.1
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• pp.49-56
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• 2002

Polypropylene is oxidized with UV/ozone as a function of UV treatment time and ozone flow rate and its surface characteristics are investigated using contart angle measurements and XPS. The aging behavior of oxidized surface is investigated under air, water and ethylene glycol as the aging media. Adhesion strength is also investigated using a lap shear test. Polar surface energy increases with increasing UV/ozone treatment time as well as ozone flow rate. No polar surface energy change is observed under water aging, while under air aging it decreases significantly within 2-3 days and reaches the close value as that of the untreated PP. Adhesion strength increases with increasing UV/ozone treatment time as well as ozone flow rate.

• Transactions of the Korean hydrogen and new energy society
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• v.27 no.5
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• pp.526-532
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• 2016

In this study, we synthesized a mediator immobilized biocatalyst([FCA/GOx]/PEI/CNT) by surface modification using ferrocene carboxylic acid(FCA), and evaluated its performance as anode catalyst for biofuel cell. Through the application of FCA on glucose oxidase (GOx), the free amine groups on the lysine residue of GOx surface reacted with carboxylic acid of FCA and make amide bond between GOx and FCA. As the result of that, the electron transfer of catalyst was increased up to 1.91 times($0.468mA{\cdot}cm^{-2}$) than the catalyst without surface modification (GOx/PEI/CNT), and high maxium power density of $1.79mA{\cdot}cm^{-2}$ was gained.

• Applied Chemistry for Engineering
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• v.20 no.4
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• pp.423-429
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• 2009

The purpose of this study is to investigate the optimal condition for the hydrogen-rich gas production and the CO removal by reforming of gliding arc plasma reforming system using biogas. The parametric screening studies were carried out according to changes of steam feed amount, catalyst bed temperature in water gas reactor and catalyst bed temperature, input air flow rate in preferential oxidation reactor. The standard condition is as follows. The steam/carbon ratio, catalyst bed temperature, total gas flow rate, input electric power and biogas composition rate ($CH_4$ : $CO_2$) were fixed 3, $700^{\circ}C$, 16 L/min, 2.4 kW and 6 : 4, respectively. The results are as follow, HTS optimum operating conditions were S/C ratio of 3 and reactor temperature of $500^{\circ}C$. LTS were S/C ratio of 2.9 and temperature of $300^{\circ}C$. Also, PROX I optimum conditions were input air flow rate of 300 mL/min and reactor temperature of $190^{\circ}C$. PROX II were 200 mL/min and $190^{\circ}C$ respectively. After having passed through each reactor, the results were as follows: 55% of $H_{2}$ yield, 0% of CO selectivity, 99% of $CH_4$ conversion rate, 27% of $CO_2$ conversion rate, respectively.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.125-131
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• 2024

In this study, synthesized Ni/Ce_xZr_1-xO₂ catalysts were coated on the surface of honeycomb metalic monoliths to investigate catalytic activity in steam reforming of methane reactions. Supports with varying Ce/Zr ratios were synthesized to observe their behavior in the reforming reaction, and catalysts with Ni contents ranging from 5 wt% to 20 wt% were prepared to analyze the effect of Ni loading contents on catalytic activity. The catalysts were characterized by XRD, BET, TPR, and SEM. The TPR analysis indicated the formation of Ni-Ce-Zr oxide with a strong interaction between the active metal Ni and CeO₂-ZrO₂ support. The 15 wt% Ni/Ce_0.80Zr_0.20O₂ catalyst exhibited the highest activity and stability in the steam reforming of methane reaction. Catalysts with enhanced activity and stability were synthesized by manufacturing composite materials using excellent oxygen storage and donor properties of CeO₂ and the thermal properties of ZrO₂.

• Journal of the Korean Electrochemical Society
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• v.5 no.2
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• pp.52-56
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• 2002

Tin oxide was coated on graphite particle by sol-gel method and an electrode with this material having microcrystalline structure for lithium ion battery was obtained by heat treatment in the range $400-600^{\circ}C$. The content of tin oxide was controlled within the range of $2.25wt\%\~11.1wt\%$. The discharge capacity increased with the content of tin oxide and also initial irreversible capacity increased. The discharge capacity of tin oxide electrode showed more than 350 mAh/g at the initial cycle and 300 mAh/g after the 30th cycle in propylene carbonate(PC) based electrolyte whereas graphite electrode without surface modification showed 140 mAh/g. When the charge and discharge rate was changed from C/5 to C/2, The discharge capacity of tin oxide and graphite electrode showed $92\%\;and\;77\%$ of initial capacity, respectively. It has been considered that such an enhancement of electrode characteristics was caused because lithium $oxide(Li_2O)$ passive film formed from the reaction between tin oxide and lithium ion prevented the exfoliation of graphite electrode and also reduced tin enhanced the electrical conduction between graphite particles to improve the current distribution of electrode.