• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.7
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• pp.689-696
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• 2010

The Because of its high thermal efficiency, the direct injection (DI) diesel engine has emerged as a promising potential candidate in the field of transportation. However, the amount of nitrogen oxides ($NO_x$) increases in the local high-temperature regions and that of particulate matter (PM) increases in the diffusion flame region during diesel combustion. In the de-$NO_x$ system the Lean $NO_x$ Trap (LNT) catalyst is used, which absorbs $NO_x$ under lean exhaust gas conditions and releases it in rich conditions. This technology can provide a high $NO_x$-conversion efficiency, but the right amount of reducing agent should be supplied to the catalytic converter at the right time. In this research, the emission characteristics of a diesel engine equipped with a micro-reformer that acts as a reductants-supplying equipment were investigated using an LNT system, and the effects of the exhaust-gas temperature were also studied.

• Fire Science and Engineering
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• v.30 no.3
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• pp.1-6
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• 2016

More than five thousands transportation fires occurannually in Korea and the resulting destruction of property and loss of life is huge and results in traffic and environmental pollution. The recent development of automobile technology such as the hybrid concept and use of bio fuels makes fire protection even more difficult due to a lack of understanding of the new adapted system including vehicle engines. In this study, a numerical simulation was performed on a PSR (perfectly Stirred Reactor) to simulate an automobile engine and to clarify the effect of gasoline/ethanol surrogates as a fuel. The temperature, NOx and soot emissions were predicted to decrease with increasing ethanol content, but that of unburned hydrocarbons was found to increase dramatically. The result will provide not only the basic thermal characteristics for engines and their after-treatment systems, but also make it possible to assess the potential for fire events in these systems when an ethanol mixed fuel is used in gasoline vehicles.

• Proceedings of the KAIS Fall Conference
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• 2006.05a
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• pp.580-581
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• 2006

본 연구의 목적은 DTP 폐수를 나노여과막으로 여과하여 처리하는 공정에서 발생하는 농축수를 처리하는 공정의 개발에 있다. 특히 DTP 장치의 특성상 발생 폐수를 별도의 폐수처리장으로 수집, 이동 하지 않고 현장에서 처리하는 소규모 패키지 시스템을 개발하고자 하였다. 아런 목표를 달성하기 위해 효율적인 여과공정인 나노여과를 적용하였고, 이 때 발생하는 농축수는 오존이나 과산화수소와 같은 산화제를 이용하여 일부 처리하고 나머지는 감압농축 및 감량화를 농한 농축수 관리 방안을 연구 하였다.

• Transactions of the Korean hydrogen and new energy society
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• v.11 no.3
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• pp.119-125
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• 2000

To improve the photochemical energy conversion efficiency and the stability of CdS particulate film electrode which is used to produce hydrogen from the aqueous $H_2S$ solution photoelectrochemically, surface treatment of this film was carried out using $TiCl_4$ solution. CdS particles for preparation of the films were synthesized by precipitation reaction of $Cd({NO_3})_2{\cdot}9H_2O$ and $Na_2S{\cdot}4H_2O$. Then, the CdS sol was hydrothermally treated for 12hr in an autoclave with the variation of treatment temperature to control the crystalline phase of particles. CdS film electrode was thus prepared by annealing at $400^{\circ}C$ for 12hr of the wet-film cast at room temperature, and subsequently surface treated with $TiCl_4$ solution. The electrodes were characterized using XRD, SEM, and the photocurrent meter. The photocurrents of Cds film electrodes prepared with surface treatment were up to two times higher than the electrodes without surface treatment, indicating about $4.0mA/cm^2$. Hydrogen production rate in a continuous flow system using photoelectrochemical or photochemical cells prepared with surface treatment also increased in proportion to the increase of photocurrents.

• Journal of Wetlands Research
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• v.25 no.4
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• pp.291-296
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• 2023

DIWS system was employed to treat hydrochloric acid gas from cold rolling mill process of iron and steel industry. Chlorine gas generated from the acid regeneration system was combined with hydrogen gas and hydrogen chloride gas was increased to 50%. After the injection of Na₂S₂O₃ to remove chlorine gas, the removal of hydrogen chloride was stably kept 87.5~88.8%, where the inflow was 13.1~13.4ppm and the outflow was 1.5~1.7ppm. DIWS system can be recommended for the real iron and steel plant because it was stably maintained not only the air emission standards but also the reduction of chemical usage.

• Journal of the Korean Chemical Society
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• v.45 no.4
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• pp.351-356
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• 2001

Planarization of the free-standing diamond film surface as smooth as possible could be obtained by using the hydrogen plasma etching with the diffusion of the carbon species into the metal alloy (Fe, Cr, Ni). For this process, we placed the free-standing diamond film between the metal alloy and the Mo substrate like a metal-diamond-molybdenum (MDM) sandwich. We set the sandwich-type MDM in a microwave-plasma-enhanced chemical vapor deposition (MPECVD) system. The sandwich-type MDM was heated over ca. 1000 $^{\circ}C$ by using the hydrogen plasma. We call this process as the hydrogen plasma etching with carbon diffusion process. After etching the free-standing diamond film surface, we investigated surface roughness, morphologies, and the incorporated impurities on the etched diamond film surface. Finally, we suggest that the hydrogen plasma etching with carbon diffusion process is an adequate etching technique for the fabrication of the diamond film surface applicable to electronic devices.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.28-33
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• 2020

In this study the possibility of hydrogen as a fuel in a small-sized two-stroke SI (Spark ignition) engine was investigated. For this purpose, experimental setup including an engine, a dynamometer, equipments for hydrogen and lubricant oil supply was prepared. And then preliminary experiments for the hydrogen-fueled engine combustion were conducted. In the case of hydrogen-fueled engines comparing to gasoline backfire occurs when the excess air ratio is lower than a specific value. This can cause engine power reduction and damage to the engine parts. The engine was controlled to operate at lean conditions to prevent backfire. Through the control of excess air ratio, the maximum engine brake power output of 3 kW was achieved in a 210 cc engine, while it was 6 kW in case of gasoline fuel.

• Proceedings of the KIEE Conference
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• 2008.04c
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• pp.233-235
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• 2008

본 논문에서는 신 재생에너지원 중 큰 축을 이루고 있는 태양광과 연료전지 발전시스템을 연계하여 하이브리드 발전시스템에 대하여 제안하였다. 태양광으로부터 발생되는 전력을 이용하여 부하에 공급함과 동시에 수전해장치를 구동시키고, 수전해장치는 전기분해시 필요한 전력을 태양광으로부터 공급받아 수소를 생산하게 된다. 본 시스템은 앞으로 가정에 적용될 수 있는 분산전원용 발전시스템의 기초 연구로써 신 재생에너지의 보급확대에 큰 기여를 할 것으로 사료된다.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2001.11a
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• pp.340-341
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• 2001

대기중의 악취물질의 분석은 현행 우리나라 악취공정시험법에 고시되어 있으나 복잡한 농축장치를 필요로하고 조작법이 복잡하고 시간이 많이 소요된다. 주요 악취물질로서 암모니아, 메틸머캅탄, 황화수소, 이황화메틸, 아세트알데히드등은 극미량에서(pub) 악취를 발생시키는 악취 주요물질이다. 그러나 이 물질들은 흡착, 반응성이 커서 정확한 분석이 어렵다. 본 연구에서는 간단한 장치로서 시료농축이 가능하며, 간단히 GC injection에 주입, 분석할 수 있는 SPME법을 이용하여 악취물질을 신속하게 분석할 수 있는 분석법을 개발하고저 하였다. 분석방법에 대한 분석재현성, 분석한계를 조사하였으며, 이 분석방법이 앞으로 악취물질분석방법으로 활용될 수 있도록 기본 분석법을 확립하고자 하였다. (중략)

• Journal of IKEEE
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• v.17 no.4
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• pp.398-406
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• 2013

Nuclear medicine imaging devices such as PET diagnose disease after injecting radiopharmaceuticals in human body for diagnosis. Radiopharmaceuticals should maintain the proper pH for human body safety. In general, pH paper is used to measure the pH of the radiopharmaceutical. pH of the sample compared with the standard color chart is used for measurement. However, the pH reading difference according to the experience of a rater can be generated. Also, a pH meter for measuring pH has a high sensitivity and contamination of the sensor must be avoided. In this paper, we developed the new hardware device for pH reading method and software was developed with vision algorithm to measure pH easily and simply.