• Transactions of the Korean Society of Mechanical Engineers
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• v.10 no.3
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• pp.367-375
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• 1986

On the hypothesis that the unstable intermediates yield by the pre-reaction of auxiliary fuel become an initiator or an explosive center which promotes the chain reaction of main fuel, various organic compounds below $C_{10}$ are injected as an auxiliary fuel prior to main injection. In the previous papers, the effects of the auxiliary fuel additions on the ignition delay period, the stability of flame, the NO concentrations in their exhaust gases have been investigated. In the present paper, to confirm where the most suitable location of lean pre-mixture for the combustion of main fuel is, and how the lean pre-mixture is contacted with main fuel, the effects of the injection timing of auxiliary fuel and the turbulence on combustion processes are investigated. Moreover, from the schlieren and color photographs of flame in the combution field, it could be found that the ignition nuclei are formed in a wider region of main spray, and that these ignition nuclei promote the development of flame, which results in the reduction of flaming duration.

• Polymer(Korea)
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• v.36 no.4
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• pp.525-530
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• 2012

In this study, silane-crosslinked organic/inorganic composite membranes were prepared by simultaneous irradiation grafting of binary monomer mixtures (styrene and 3-(trimethoxysilyl)propyl methacrylate (TMSPM)) with various compositions onto a poly(ethylene-alt-tetraethylene) (ETFE) film and followed by sol-gel processing and sulfonation to provide a silane-crosslinked structure and a proton conducting ability, respectively. The Fourier transform infrared spectroscopy (FTIR) and thermo gravimetric analysis (TGA) were utilized to confirm the crosslinking of ETFE-g-PS/PTMSPM films. The prepared membranes with similar ion exchange capacity but a different TMSPM content were selected and their membrane properties were compared. The ETFE-g-PSSA/PTMSPM membranes were characterized by water uptake, dimensional stability, and proton conductivity after sulfonation. The membrane electrode assemblies (MEA) of the prepared membranes were fabricated and their single cell performances were measured.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2009.05a
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• pp.365-368
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• 2009

A new concept of a small thruster for altitude control of a micro/nano class satellite is developed, which utilizes the pulsed laser energy. As the laser-based thruster does not require burning of any fuel, it gives promise of small satellite design criteria, namely light weight and cost effectiveness. In this paper, we develop gel-type material for generating strong plasma plume for enhancing thrust for propulsion. Moreover, we quantify the level of thrust via the momentum coupling coefficient measured by the pendulum system. We discover that the driving force is significantly improved via the gel-typed propellant for laser ablation.

• Transactions of the Korean hydrogen and new energy society
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• v.17 no.3
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• pp.241-247
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• 2006

The catalytic performances for CO preferential oxidation in hydrogen-rich fuels were investigated by varying the types of alumina supports, additives excluding platinum, and synthetic methods of impregnation and sol-gel synthesis. The reactions were conducted in the range of $25{\sim}300^{\circ}C$ over Pt, Co, and/or Na impregnated catalysts supported on commercial gamma-alumina, pseudoboehmite, or sol-gel derived xerogels. Catalytic activities were enhanced by cobalt addition due to strong Pt-Co interactions in the bimetallic phase. Additional sodium promoted not only the formation of the Pt-Co bimetallic interphase but also oxygen adsorption capability, giving rise to increase in the CO oxidation rate at lower temperatures. Moreover, chemical interaction between Pt and Co was considerably enhanced by sol-gel synthesis.

• Journal of the korean Society of Automotive Engineers
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• v.8 no.4
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• pp.24-35
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• 1986

현재 주요 가스상물질은 미국의 경우 규제전보다 일산화탄소가 96%, 탄화수소 96%, 질소산화물 76%가 개선되어 어느정도 안정단계에 들어 갔다고 볼 수 있다. 그러나, 입자상물질규제는 디이 젤자동차의 증가와 더불어 1986-1994기간동안 대폭적으로 강화되고 있다. 그러나 자동차 배출 가스중에는 수백가지의 화학물질이 존재하고 인체에 유독한 물질은 규제물질외에도 엄청나게 많다. 따라서 1977년 8월에 개정된 미국의 대기정정법(CAA, clean air act)에는 "신규 제작자동 차나 엔진에 사용되는 어떠한 방지장치, 시스템 또는 부품도 공중보건, 복지 및 안전에 부당한 위험을 일으키거나 일으키는 요인이 될 수 없다"(참조, CAA 202 (a) 및 CFR 86.084-5)고 규 정하고 있다. 이에 따라 미국환경청에서는 회람 등을 통하여 가능한 독성물질에 대하여 경우에 따라 측정할 것을 요구하고 있다. 국내 환경보전법에도 자동차연료첨가제 사용할 때 현저하게 유해한 물질이 배출된다고 인정하는 때에는 그 사용을 규제할 수 있게 되어있고 새로 제정될 자동차 배출가스 시험검사방법 및 절차에 관한 규정에 이에 관한 사항을 추가할 움직임이 있다. 물론 미규제물질의 규제하는 인체에 대한 피해정도나 측정방법 등의 여러 가지 문제가 수반되나 장기적인 국민보건과 환경보전 측면에서 신중하게 다루어져야 되리라 봐서 여러 가지 오염물질의 현황이나 분석방법 등에 대하여 기술코자 한다.여 기술코자 한다.

• Applied Chemistry for Engineering
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• v.24 no.5
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• pp.443-455
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• 2013

Electrochemical studies on charge transfer reactions across the interface between two immiscible electrolyte solutions (ITIES) have greatly attracted researcher's attentions due to their wide applicability in research fields such as ion sensing and biosensing, modeling of biomembranes, pharmacokinetics, phase-transfer catalysis, fuel generation and solar energy conversion. In particular, there have been extensive efforts made on developing sensing platforms for ionic species and biomolecules via gelifying one of the liquid phases to improve mechanical stability in addition to creating microscale interfaces to reduce ohmic loss. In this review, we will mainly discuss on the basic principles, applications and future aspects of various sensing platforms utilizing ion transfer reactions across the ITIES. The ITIES is classified into four types : (i) a conventional liquid/liquid interface, (ii) a micropipette supported liquid/liquid interface, (iii) a single microhole or an array of microholes supported liquid/ liquid interface on a thin polymer film, and (iv) a microhole array liquid/liquid interface on a silicon membrane. Research efforts on developing ion selective sensors for water pollutants as well as biomolecule sensors will be highlighted based on the use of direct and assisted ion transfer reactions across these different ITIES configurations.