C1-C4 알칸에 대한 자발화된 부상화염의 안정화

최병철(B. C. Choi),정석호(S. H. Chung) 한국연소학회 2010 KOSCOSYMPOSIUM논문집 Vol.- No.40

The autoignition characteristics of laminar lifted flames of methane, ethane, propane and n-butane fuels have been investigated experimentally in coflow air with elevated temperature over 800 K. The lifted flames were categorized into three regimes depending on the initial temperature and fuel mole fraction; (1) non-autoignited lifted flame, (2) autoignited lifted flame with tribrachial (or triple) edge, and (3) autoignited lifted flame with mild combustion. For the non-autoignited lifted flames for relatively low temperature, the existence of lifted flame depended on the Schmidt number of fuel, such that only the fuels with Sc > 1 exhibited stationary lifted flames, similar to the case with atmospheric temperature. The balance mechanism between the propagation speed of tribrachial flame and local flow velocity stabilized the lifted flames. At relatively high initial temperatures, either autoignited lifted flames having tribrachial edge or autoignited lifted flames with mild combustion existed regardless of the Schmidt number of fuel. The adiabatic ignition delay time played a crucial role for the stabilization of autoignited flames. Especially, heat loss during the ignition process should be accounted for, such that the convection time, defined by the autoignition height divided by jet velocity was correlated well with the square of the adiabatic ignition delay time for the critical autoignition conditions. The liftoff height was also correlated well with the square of the adiabatic ignition delay time.

HC Adsorber 를 이용한 가솔린 엔진의 냉시동시 탄화수소 저감기술에 관한 연구

최병철(B.C.Choi),이남석(N.S.Lee),손건석(G.S.Son) 한국자동차공학회 1998 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1998 No.11_1

Experiments were carried out to investigate the characteristics of the hydrocarbon emissions and cold start hydrocarbon reduction in gasoline engine. The adsorber used was Pd/Rh catalyst-loaded zeolite monolith type. Experiments of the hydrocarbon emissions reduction were conducted in the adsorber temperature of 50, 100, 200 and 300℃ It was found that the hydrocarbon emissions were efficiently trapped during the adsorber temperature below 1001 by physisorption, and were reduced gradually by the catalytic activation of Pd/Rh catalysts in the adsorber temperature above 1001. Methane, ethylene and n-butane concentration in the middle of C1 to C6 increase as the fuel/air mixture to be rich and as the engine speed decreases. The medium size hydrocarbon emissions from C4 to C6 were significantly reduced as the adsorber temperature increases, but the small size hydrocarbon emissions from Cl to C3 were increased because of molecules cracking phenomenon.<br/>

인공심장판막 실패에 대한 재치환술의 임상적 고찰

최병철,유환국,안욱수,허용,김병열,이정호,유회성,Choi, B.C.,Yoo, H.K.,Ahn, W.S.,Hur, Y.,Kim, B.Y.,Yoo, H.S. 대한심장혈관흉부외과학회 1991 Journal of Chest Surgery (J Chest Surg) Vol.24 No.7

To evaluate risks, complications and mortality of reoperations on heart valve prosthesis, we reviewed clinical records of 53 patients who underwent reoperation because of prosthetic valve failure[PVF], from Jan 1959 through Jun. 1991. They had undergone 48 mitral, 10 aortic valve rereplacement Primary tissue failure was the main cause of reoperation : it occurred in 51 valves at a mean postoperative interval of 58 months. Calcification and collagen disruption of prosthesis were main causes of primary tissue failure in macro and micropathology, In 3 failing mechanical prostheses, paravalvular leak was in 2 cases, another one case had the thrombi at the hinge portion. If conditions such as emergency operation with or without endocarditis, thromboembolism and advanced NYHA functional class are prevented, we think that reoperative valve replacement has similar morbidity and mortality to initial valve replacement surgery. But our sturdy represents higher mortality [22.6%] because of late surgical intervention failing the prevention of conditions leading to myocardial damage. In conclusion if the tearing, calcification, and a new murmur were detected the early reoperation should be considered to increase late survival.

u-IT 기술혁신과 산업변화

최병철,박기식,Choi, B.C.,Park, K.S. 한국전자통신연구원 2006 전자통신동향분석 Vol.21 No.2

최근 컨버전스가 하나의 트렌드로 정착해 감에 따라, 그 동안 기기 및 기능 중심으로진행되던 디지털컨버전스가 이제는 인간, 사물, 공간을 유기적으로 통합하는 차원에서인간과 사물, 그리고 공간과 IT가 한데 어우러지는 유비쿼터스 양상으로까지 발전하고있다. 유비쿼터스 컴퓨팅 기술의 발달과 더불어 이제 유비쿼터스는 단순한 개념정립단계를 넘어 u-City, u-Health, u-교통, u-교육, u-유통/물류 등 수많은 분야에서 현실에 접목되면서 점점 더 구체화되고 있다. 유비쿼터스 기술이 가져오게 될 소위 유비쿼터스 IT 혁명은 소리없이 우리에게 다가오고 있으나, 그것이 몰고 올 변화는 우리 생활양식의 변화를 포함하여 실로 막대할 것으로 예측되고 있다. 이에 본 고에서는 u-IT시대를 향한 기술발전의 방향과 함께 그에 따른 관련 산업의 변화되는 모습을 예측해보고, 나아가서는 u-IT 사회를 조기에 구현하기 위해 해결되어야 할 주요한 과제들은 무엇인지를 간단하게 살펴보고자 한다.

지능형 차량 보안 기술 동향

최병철,한승완,정병호,김정녀,Choi, B.C.,Han, S.W.,Chung, B.H.,Kim, J.N. 한국전자통신연구원 2007 전자통신동향분석 Vol.22 No.1

국내외적으로 지능형 차량 및 텔레매틱스/ITS 연구 개발을 통해서 차량에 IT 기술 접목을 위한 노력을 가속화하고 있다. 우리나라의 경우 산업자원부가 미래 10대 전략품목으로 자동차 부분에서 지능형 차량을 선정하였으며, 정보통신부는 u-IT839의 핵심서비스로 텔레매틱스/ITS 서비스를 추진하고 있다. EU는 i2010 Flagship에서 intelligentcar initiative 프로젝트를 통해 지능형 차량 및 보안을 위한 전략 수립과 세부과제를 수행하고 있다. 또한, IEEE 802.11p/P1609(WAVE)와 ISO TC204/WG16CALM에서는 차량 통신 보안 및 서비스에 대해서 고려하고 있다. 현재 지능형 차량과 관련하여서는 다양한 사업 모델이 제시되고 있으며, 자동차 업계의 BM과 이동통신 업계의 AM이 동반 성장하고 있다. 본 기고문은 지능형 차량 및 텔레매틱스/ITS와 관련한 보안 기술 동향을 살펴본다.

SO2 가스에 의한 철 - 알루미늄 합금의 고온 황화 부식에 미치는 탄소의 영향

최병철,강성군 ( B . C . Choi,S . G . Kang ) 한국부식방식학회 1988 Corrosion Science and Technology Vol.17 No.1

스트립을 이용한 요분석시스템의 개발과 퍼지추론에 의한 검사결과 평가에 관한 연구

전계록,이승진,최병철,안시훈,하광,김주열,김재형,Jun, K. R.,Lee, S. J.,Choi, B. C.,An, S. H.,Ha, K.,Kim, J. Y.,Kim, J. H. 대한의용생체공학회 1998 의공학회지 Vol.19 No.5

본 연구에서는 요분석용 스트립을 이용하여 요의 상태를 정량적·정성적으로 측정할 수 있는 요분석시스템을 구현하였다. 요분석시스템의 분석 알고리듬은 온도 변화, 전원 노이즈 통의 외란에 강인한 특성을 나타내기 위하여 퍼지 논리를 적용하였다. 강인하고 안정적인 요분석시스템을 설계하기 위하여 스트립 9가지 패드의 분강학적 특성을 검토하였다. 요분석시스템 하트웨어와 소프트웨어로 구성되었다. 요분석시스템의 하드웨어는 단일칩 마이크로프로세서를 사용하였고, 주변장치들로는 광하부, 트레이 제어, 전치증폭부, PC와의 통신, 열전사 프린터 및 동작 상태 표시기로 구성하였다. 요분석시스템의 소프트웨어는 시스템 프로그램과 분류 프로그램으로 구성하였다. 시스템 프로그램은 시스템 제어와 데이터 취득 및 분석을 수행하도록 하였다. 분규 프로그램은 퍼지추론부와 멤버쉽함수 발생기로 구성되었다 멤버쉽함수 발생기는 정도관리의 통계학적 방법을 이용하여 삼각형 멤버쉽함수를 생성하였다. 측정된 데이터는 PC로 전송되고, 전송된 데이터는 C++로 작성된 데이터 관리 및 취득 프로그램에 의해 저장된다. 요분석시스템의 정확도와 퍼지분류기의 안정성은 표준시료를 이용하여 평가하였다. 실험결과는 검사항목과 만족한 일치를 보였다. In this paper, we implemented the urine analysis system capable of measuring a qualitative and semi-quantitative and assay using strip. The analysis algorithm of urine analysis was adopted a fuzzy logic-based classifiers that was robust to external error factors such as temperature and electric power noises. The spectroscopic properties of 9 pads In a strip were studied to developing the urine analysis system was designed for robustnesss and stability. The urine analysis system was consisted of hardware and software. The hardware of the urine analysis system was based on one-chip microprocessor, and Its peripherals which composed of optic modulo, tray control, preamplifier, communication with PC, thermal printer and operating status indicator. The software of the urine analysis system was composed of system program and classification program. The system program did duty fort system control, data acquisition and data analysis. The classification program was composed of fuzzy inference engine and membership function generator. The membership function generator made triangular membership functions by statical method for quality control. Resulted data was transferred through serial cable to PC. The transferred data was arranged and saved be data acquisition program coded by C+ + language. The precision of urine analysis system and the stability of fuzzy classifier were evaluated by testing the standard urine samples. Experimental results showed a good stability states and a exact classification.

[가솔린엔진부문] 저공해 자동차용 신 삼원촉매의 개발에 관한 연구

최병철(B.C.Choi),임명택(M.T.Lim),명광재(K.J.Myong),정종우(J.W.Jung),정명근(M.G.Jung) 한국자동차공학회 1999 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1999 No.11_1

The research was conducted to develop a new three-way catalyst which has better low temperature activity and durability than current ones. Honeycomb type catalysts with different Rh/Pd, Rh/Pd/Pt loading ratios were tried in this experiment Conversion effectiveness of each catalyst was measured as a function of temperature and redox ratio using a model gas test bench. In addition, a single cylinder gasoline engine was used to find the conversion characteristics for THC, CO and CO2. The conversion characteristics for LIHCs(CI-C6) were also analyzed. Catalyst with Rh/Pd=1/18 loading ratio showed the best conversion effectiveness among the eight catalysts, and the light-off temperature of this catalyst was 26℃ for 50% THC conversion

자동차 배관기용 다공성산화티탄 적용 단열재의 열전도 특성

최병철(B.C. Choi),정우남(W.N. Juhng),김종호(J.H. Kim),김대석(D.S. Kim),정민철(M.C. Jeong),노승천(S.C. Ro),링펑(L. Feng) 한국자동차공학회 2013 한국자동차공학회 지부 학술대회 논문집 Vol.2013 No.5-1

공연비 변화에 따른 천연가스 자동차용 촉매의 정화 특성

최병철(B.C.Choi),정종우(J.W.Jeong),임명택(M.T.Lim),김영길(Y.K.Kim) 한국자동차공학회 1997 한국자동차공학회 춘 추계 학술대회 논문집 Vol.1997 No.11_2

In this study. purification chracteristics has been investigated on the catalystic reaction of methane from the simulated natural gas vehicle (NGV) exhaust on a palladium catalysat. Parameters that effect the catalytic reaction of methane considered were exhaust gas components such as O₂. NO. CO. H₂O. Two kinds of Pd catalyst used were different from additives. The conversion efficiency of methane in the three-way catalysts was sharply reduced in the range of redox ratio from 1.0 to 0.7. It was found that CH₄ was oxidized by O₂ in the lean region and by a simultaneous reaction at NO and O₂ in the rich region. At a higher concentration of H₂O. the mehtane conversion efficiency was rapidly reduced in the range of redox ratio from 1.5 to 1.2.