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미생물의 유전자(Genome) 해석과 임상세균학에 이용
김성광 영남대학교 의과대학 2002 Yeungnam University Journal of Medicine Vol.19 No.1
With the establishment of rapid sequence analysis of 16S rRNA and the recognition of its potential to determine the phylogenetic position of any prokaryotic organism, the role of 16S rRNA similarities in the present species definition in bacteriology need to be clarified. Comparative studies clearly reveal the limitations of the sequence analysis of this conserved gene and gene product in the determination of relationship at the pathogenic strain level for which DNA-DNA reassociation experiments still constitute the superior method. Since today the primary structure of 16S rRNA is easier to determine than hybridization between DNA strands, the strength of the sequence analysis is to recognize the level at which DNA pairing studies need to be performed, which certainly applies to similarities of 97% and higher.
김성광,Wanlin Wang,강윤배 대한금속·재료학회 2015 METALS AND MATERIALS International Vol.21 No.4
Surface tension of multicomponent liquid steel was calculated based on the concept proposed by Butler, which assumes a chemical equilibrium between a bulk phase and a surface phase of a monolayer. Requirement for the calculation of the surface tension was categorized as: 1) accurate description of partial excess Gibbs energies of solutes in the liquid steel, in particular for those of non-metallic solutes such as S, C, etc., 2) physical properties of pure components, such as surface tension and molar volume, and 3) possibility of solving a series of Butler equations for multicomponent liquid steel. In the present study, it is proposed to use the Modified Quasichemical Model in order to describe the partial excess Gibbs energies of solutes, and to use the Constrained Gibbs Energy Minimization in order to solve equilibrium between the bulk and the surface phases of the multicomponent liquid steel. Physical properties of non-stable pure components such as S, C, were treated as variables to reproduce known experimental data in binary systems. The proposed method can be easily extended into multicomponent liquid steel. Examples of the surface tension calculations are presented.
좁은 공간내의 밀폐형 장치 냉각시스템에 대한 열평형 평가
김성광,안석환,남기우 한국해양공학회 2007 韓國海洋工學會誌 Vol.21 No.3
In this study, the heat balance test of an engine was conducted, and the heat released to coolant is measured and corrected using a power adjustment factor for high fuel temperature to simulate heat rejection of the engine. An engine-converter matching simulation program which can compute the engine speed, transmission output speed, transmission input and output power is developed from the vehicle, transmission and engine performance curve. With this information and the engine heat rejection characteristics, the engine and transmission heat rejection rates can be determined at given condition. In analyzing the air mass flow, a sub program computing the air mass flow rate from the equation of the pressure balance between cooling fan static pressure rise and pressure losses of cooling components is developed.1. 서 론 최근 고출력 디젤엔진을 장착한 밀폐형차량은 냉각 요구조건은 점점 가혹해지고 있는 반면, 설치공간은 작아지고 복잡해 지고 있어 제한된 공간에서 적절한 냉각용량을 확보하는 것은 어려운 일이며 이에 따라 좁은 공간내에서 차량에 알맞은 냉각용량을 설계는 매우 중요한 인자가 된다(Corbel, 1987). 따라서 엔진 및 차량 제조업체에서는 차량의 사용조건을 고려하여(-32℃~+50℃) 과열 및 과냉 방지와 엔진의 열효율을 극대화할 수 있는 적절한 냉각용량을 결정하여 가능한 한 실제 차량에 적용한 조건에 유사한 상태로 차량 냉각시험을 실시하여 적합성을 검토하고 최종적으로 차량시험을 실시하여 시스템을 증명할 필요가 있다. 특히 밀폐형차량의 경우 차량 냉각을 시킬수 있는 열교환기 및 휀의 설계가 무엇보다도 중요하다. 압축착화방식을 사용하는 디젤엔진의 냉각 손실은 대략 20~30(%) 정도이며 엔진의 내구성 및 열효율을 높이기 위한 방안으로 고온의 연소가스와 접촉하는 연소실을 일정한 온도범위 이내로 유지시켜 주어야 한다(Xu et al., 1984; Chiang et al., 1982; 1982; Nutt and Poehlma, 1982). 차량냉각시스템에 대한 요구성능의 증가에 따라 방열기의