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김형진,박병선,전성현 한국정보사회진흥원 2005 정보화정책 Vol.12 No.3
IT 환경의 급격한 변화와 소프트웨어 위기 이후 기업의 정보화에 대한 요구는 다양화게 대두되어 왔으며, 최근에는 정보화의 성과가 기대에 미치지 못한다는 불만과 함께 정보화에 대한 투자를 다시 생각해보려는 시각이 일부에서 일고 있다. 이러한 정보화 및 정보화투자에 대한 문제점을 새롭게 해결하려는 노력이 바로 정보기술아키텍처(ITA) 또는 Enterprise Architecture(EA)이다. ITA/EA에 대한 효용성은 미국을 비롯하여 해외 선진국에서 이미 입증되었으며, 현재 국내에서도 ITA/EA에 대한 관심이 날로 높아져 시범사업을 비롯하여 법제화까지 이르게 되었다. 하지만 ITA/EA가 확산되기 위해서는 많은 어려움과 시간을 필요로 하는 것이 현실이다. 향후 국내 ITA/EA 도입 및 활용시 위험부담 최소화와 투자 극대화의 일환으로써 본 연구는 국내 ITA/EA 구축 및 도입기관의 담당자를 대상으로 국내 ITA/EA 도입 환경, 도입 목적, 도입 과정, 도입 결과로 나누어 국내 ITA/EA 도입현황 조사를 통하여 향후 활성화 방안에 대한 연구를 수행하였다.
Kim, Hyoung-Juhn The Membrane Society of Korea 2003 Korean Membrane Journal Vol.5 No.1
1,3,5-Sustitituted polyphenylene type dendrimers were synthesized. The dendrimer was heated in cone. H$_2$SO$_4$ at 120$^{\circ}C$. The reaction mixture was precipitated to ether after simple filtration to get para-sulfonated dendrimer as the chief product. To give mechanical properties to the sulfonated dendrimer, it was partially cross-linked with phenyl ether in the medium of P$_2$O$\sub$5/ and CH$_3$SO$_3$H.
Kim, GyeongHee,Eom, KwangSup,Kim, MinJoong,Yoo, Sung Jong,Jang, Jong Hyun,Kim, Hyoung-Juhn,Cho, EunAe American Chemical Society 2015 ACS APPLIED MATERIALS & INTERFACES Vol.7 No.50
<P>The membrane electrolyte assembly (MEA) designed in this study utilizes a double-layered cathode: an inner catalyst layer prepared by a conventional decal transfer method and an outer catalyst layer directly coated on a gas diffusion layer. The double-layered structure was used to improve the interfacial contact between the catalyst layer and membrane, to increase catalyst utilization and to modify the removal of product water from the cathode. Based on a series of MEAs with double-layered cathodes with an overall Pt loading fixed at 0.4 mg cm<SUP>–2</SUP> and different ratios of inner-to-outer Pt loading, the MEA with an inner layer of 0.3 mg Pt cm<SUP>–2</SUP> and an outer layer of 0.1 mg Pt cm<SUP>–2</SUP> exhibited the best performance. This performance was better than that of the conventional single-layered electrode by 13.5% at a current density of 1.4 A cm<SUP>–2</SUP>.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/aamick/2015/aamick.2015.7.issue-50/acsami.5b07346/production/images/medium/am-2015-07346t_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/am5b07346'>ACS Electronic Supporting Info</A></P>
PBI Derivatives : Polymer Electrolyte Fuel Cell Membrane for High Temperature Operation
Kim, Hyoung-Juhn,Lim, Tae-Hoon 한국공업화학회 2004 Journal of Industrial and Engineering Chemistry Vol.10 No.7
To replace Nafion type perfluorosulfonated polymers, non-sulfonated hydrocarbon-based polybenzimidazole (PBI) derivatives have been prepared for a polymer electrolyte fuel cell (PEFC) membrane. The PBI membranes are easily doped with strong inorganic acid to get proton conductivity. They perform as a PEFC membrane at high temperature (120~200℃) under non-humidified condition. The PBI derivatives are very promising materials for proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC).
Hydrolytic Stability of Sulfonic Acid-Containing Polyimides for Fuel Cell Membranes
Kim Hyoung-Juhn,Litt Morton H.,Shin Eun-Mi,Nam Sang Yong The Polymer Society of Korea 2004 Macromolecular Research Vol.12 No.6
The long-term stability of sulfonic acid-containing polyimides has been investigated. The hydrolytic degradation of homopolyimide and the block copolyimide comprising $27\;mol\%$ of 2,2'-bis(trifluoromethyl)benzidine and $9\;mol\%$ of m-phenylenediamine (BTFMB27mPl0[7/(3+1)]), was quantified through viscosity measurements and FT-IR spectroscopic analyses. The viscosity decrease with respect to time and the degradation rate were similar. The degrees of degradation with respect to time under ambient conditions and at elevated temperature in water were monitored by FT-IR spectroscopy. A new absorption peak was observed at $1786\;cm^{-1},$ which we corresponds to the presence of anhydride end groups formed by hydrolytic scission of the imide rings.
Kim, Eun‐,Ki,Lee, So Young,Nam, Sang Yong,Yoo, Sung Jong,Kim, Jin Young,Jang, Jong Hyun,Henkensmeier, Dirk,Kim, Hyoung‐,Juhn,Lee, Jong‐,Chan Published for SCI by Elsevier Applied Science 2017 Polymer international Vol.66 No.12
<P><B>Abstract</B></P><P>An isophthalaldehyde bisulfite adduct (IBA) was synthesized using a reaction between sodium sulfite and isophthalaldehyde. Isophthalaldehyde monosulfite adduct (IMA) was inevitably synthesized during the reaction. Because IBA and IMA have similar solubility in water, it is difficult to separate them through a recrystallization process. In order to obtain pure IBA, an excess of sodium sulfite was used. Highly pure IBA was subsequently obtained without the need for recrystallization. The IBA was then used as the starting monomer for the synthesis of poly[2,2′‐(<I>m</I>‐phenylene)‐5,5′‐bisbenzimidazole] (PBI). Previous isolation methods for IBA hindered the synthesis of high molecular weight PBI. This new synthetic procedure produces high‐purity IBA, which can be used to synthesize high molecular weight PBI. © 2017 Society of Chemical Industry</P>
Effects of anode flooding on the performance degradation of polymer electrolyte membrane fuel cells
Kim, Mansu,Jung, Namgee,Eom, KwangSup,Yoo, Sung Jong,Kim, Jin Young,Jang, Jong Hyun,Kim, Hyoung-Juhn,Hong, Bo Ki,Cho, EunAe Elsevier 2014 Journal of Power Sources Vol.266 No.-
<P><B>Abstract</B></P> <P>Polymer electrolyte membrane fuel cell (PEMFC) stacks in a fuel cell vehicle can be inevitably exposed to harsh environments such as cold weather in winter, causing water flooding by the direct flow of condensed water to the electrodes. In this study, anode flooding was experimentally investigated with condensed water generated by cooling the anode gas line during a long-term operation (∼1600 h). The results showed that the performance of the PEMFC was considerably degraded. After the long-term experiment, the thickness of the anode decreased, and the ratio of Pt to carbon in the anode increased. Moreover, repeated fuel starvation of the half-cell severely oxidized the carbon surface due to the high induced potential (>1.5 V<SUB>RHE</SUB>). The cyclic voltammogram of the anode in the half-cell experiments indicated that the characteristic feature of the oxidized carbon surface was similar to that of the anode in the single cell under anode flooding conditions during the long-term experiment. Therefore, repeated fuel starvation by anode flooding caused severe carbon corrosion in the anode because the electrode potential locally increased to >1.0 V<SUB>RHE</SUB>. Consequently, the density of the tri-phase boundary decreased due to the corrosion of carbons supporting the Pt nanoparticles in the anode.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Anode flooding can occur by direct flow of condensed water in humidified fuel. </LI> <LI> Anode flooding induces local fuel starvation and high potential in the anode. </LI> <LI> High potential locally present in the anode results in anode carbon corrosion. </LI> <LI> Anode carbon corrosion plays a key role in MEA degradation by anode flooding. </LI> </UL> </P>
Kim, Hoyoung,Hwang, Eunkyoung,Park, Hyanjoo,Lee, Byung-Seok,Jang, Jong Hyun,Kim, Hyoung-Juhn,Ahn, Sang Hyun,Kim, Soo-Kil Elsevier BV 2017 Applied Catalysis B Vol.206 No.-
<P><B>Abstract</B></P> <P>Electrodeposited Cu<I> <SUB>x</SUB> </I>Mo<SUB>100− <I>x</I> </SUB> catalysts were prepared on a Ti substrate for the hydrogen evolution reaction (HER) in acidic medium. By varying the electrolyte composition for electrodeposition, the atomic concentration of the Cu<I> <SUB>x</SUB> </I>Mo<SUB>100− <I>x</I> </SUB> electrocatalysts could be controlled, and the Mo content ranged between 0.8 and 6.9%. In the first cyclic voltammetry scan in a 0.5M H<SUB>2</SUB>SO<SUB>4</SUB> electrolyte, the recorded HER current densities of the Cu<I> <SUB>x</SUB> </I>Mo<SUB>100− <I>x</I> </SUB> electrocatalysts at −0.50V<SUB>RHE</SUB> increased on increasing the Mo content to 3.8%; then, a further increase in Mo to 6.9% led to a saturation in the HER activity. The maximum value of the normalized current density with respect to the electrochemical surface area and the loading mass was found for the Cu<SUB>99.2</SUB>Mo<SUB>0.8</SUB> electrocatalyst. Characterization of the prepared catalysts revealed that the enhancement of catalytic activity originates from changes in the grain size and electronic structure. To operate a single cell of the proton exchange membrane water electrolyzer (PEMWE), we electrodeposited CuMo catalyst on carbon paper, and this was used as the cathode, while IrO<SUB>2</SUB> electrodeposited on carbon paper was used as the anode. The cell performance was normalized with respect to the metal mass loading and was found to be 3.4A/mg<SUB>metal</SUB> at 1.9V, a 2.2–10.8 times better catalyst cost-activity relationship compared to that of currently reported PEMWEs using Pt-based cathodes. Consequently, the results presented here show that non-noble metal cathodes can be used for PEMWE operation.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Cu<SUB>x</SUB>Mo<SUB>100−x</SUB> catalysts are prepared for hydrogen evolution reaction in acidic medium. </LI> <LI> Small amount of Mo enhances catalytic activity of Cu<SUB>x</SUB>Mo<SUB>100−x</SUB> catalysts. </LI> <LI> Water electrolyzer with non-precious catalyst demonstrates reasonable performance. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>[DISPLAY OMISSION]</P>