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자기적 방법에 의한 0.85% 탄소강의 열처리에 따른 미세조직 및 기계적 성질 평가
변재원,권숙인,Byeon, Jai-Won,Kwun, S.I. 한국재료학회 2003 한국재료학회지 Vol.13 No.2
Microstructures and mechanical properties of variously heat treated 0.85% carbon steel(eutectoid steel) were evaluated by magnetic property measurements. Microstructural analysis (pearlite interstellar spacing), measurement of mechanical properties(Rockwell hardness, yield stress, fracture stress) and magnetic properties(coercivity, remanence, hysteresis loss, saturation magnetization) were performed to clarify mutual relationships among these parameters. Water quenched specimens with martensite structure showed much higher coercivity and remanence than air cooled or furnace cooled specimens with pearlite structure. The linear dependence of coercivity and remanence on pearlite interlamellar spacing as well as on Rockwell hardness, yield stress and fracture stress was observed in the pearlitic steel. Hysteresis loss and saturation magnetization showed no distinct trend with pearlite interlamellar spacing.
Integrated strategy for concurrent production of furfuryl alcohol and glycerol oxygenates
변재원,김동인,이대원,김형주,한지훈 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.73 No.-
This paper develops an integrated strategy that combines two conversion technologies to concurrentlyconvert biomass-derived feedstocks (furfural (FF) and glycerol (Gly)) to furfuryl alcohol (FFA) andglycerol derivatives respectively. Effective utilization of H2 is a key challenge for techno-economicfeasibility of this integrated strategy. Catalytic hydrogenation of FF requires H2 which can be supplied byelectrocatalytic oxidation of Gly. This integration of processes yields FFA at lower cost than the currentmarket price and a stand-alone FFA-production strategy. This strategy of integrating technologies toproduce different products from different feedstocks may be widely applicable for production of bioderivedchemicals.
변재원,한지훈 한국공업화학회 2021 Journal of Industrial and Engineering Chemistry Vol.104 No.-
In terms of circular economy (CE), the coproduction of biofuels and bio-based chemicals could be a feasiblestrategy to improve the biorefinery economics. However, this approach is significantly affected bythe variation of the techno-economic parameters. Thus, we evaluated the techno-economic feasibilityof an integrated strategy through deterministic and stochastic models for the coproduction of biofuels(jet fuel range alkenes (JFA)) and bio-based chemicals (pentanediols and pentane) to identify the impactof uncertainty in technological cycle on the CE action plan. The deterministic analysis estimated the minimumJFA selling price (MJSP) expressed per gasoline gallon equivalents (GGE) and led to the identificationof six major techno-economic parameters having a significant impact on the economics. Stochasticanalysis was performed based on the Monte Carlo simulation, leading to probabilistic results on the economicfeasibility of the integrated strategy, taking into account the uncertainty in the six identifiedparameters. In five of the six scenarios developed considering each uncertainty, the chances of MJSP beinglower than the maximum biofuel price (USD 3.10 GGE 1) in the last three years (2017–2019) were higherthan 50% (53.2–88.1%), implying that, despite the uncertainties reflected in the major techno-economicparameters, the integrated strategy could be a risk-averse investment.
보자력 측정에 의한 아공석강 및 공석강의 열처리에 따른 미세조직 평가
변재원,김정석,권숙인,Byeon Jai Won,Kim C. S.,Kwun S. I. 한국재료학회 2004 한국재료학회지 Vol.14 No.8
The microstructures of variously heat treated hypoeutectoid($0.45\%$ carbon) and eutectoid($0.85\%$ carbon) steel were characterized by magnetic coercivity measurement. The effect of spheroidization of cementites on the coercivity was investigated for $0.45\%$ carbon steel. In case of $0.85\%$ carbon steel, microstructural parameters such as prior austenite grain size, phase and pearlite interlamellar spacing were measured along with coercivity to investigate the relationships between them. Prior austenite grain size had little effect on the measured coercivity. Coercivity was observed to be high in order of martensite, pearlite and ferrite phases. The linear decrease of coercivity with increasing pearlite interlamellar spacing was found. The effect of each microstructural factor on the coercivity and the potential of coercivity as a nondestructive evaluation parameter for assessing microstructures of steel products are discussed.
Effect of thermal exposure of 2.25Cr-1Mo steel on magnetic Barkhausen noise
변재원,권숙인 한국물리학회 2004 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.45 No.3
In this research, the eect of microstructural changes of 2.25Cr-1Mo steel due to long-time exposure to high temperature (thermal degradation) on magnetic Barkhausen noise was investigated. Isothermal degradation heat treatment was performed at 630 C for up to 4800 hours. Microstructural parameters (size and number of carbides per unit area) were measured, along with magnetic Barkhausen noise (rms voltage and frequency spectrum), in order to investigate the relationships between them. The rms voltage of magnetic Barkhausen noise (MBNrms) was observed to increase rapidly in the initial 1000 hours of thermal exposure time and then very slowly thereafter. The initial sharp increase of MBNrms was attributed to rapid disappearance of a large number of needle-shaped carbides. Peak amplitude of the frequency spectrum tended to increase with increasing thermal exposure time.
Devastating botulism outbreak in cattle, associated with contaminated soil
변재원,정병열,김하영,이경현,문운경,윤순식,박소영,이오수,이명헌,배유찬 한국예방수의학회 2013 예방수의학회지 Vol.37 No.2
We describe here cases of botulism at two dairy cattle farms where the soil was submerged by flooding from an adjacent river. All cattle at farms 1 and 2 (91 and 56 head, respectively) died or were euthanized with posterior flaccid paralysis and recumbency. Necropsy and histopathological examination showed no specific lesions. Botulinum toxin type B was detected in sera of the affected cattle, and type D toxin was found in ruminal contents and soil from cattle pens at both farms. A likely source of the botulinum toxin is the soil of the adjacent river, from which toxins were introduced during flooding. To our knowledge, these appear to be the first cases of bovine botulism associated with contaminated pen soil after flooding.
통합 바이오리파이너리 공정 개발 및 경제성 평가 : corn stover 및 글리세롤의 촉매전환 공정
변재원,안유찬,김주연,김동인,한지훈 한국공업화학회 2018 한국공업화학회 연구논문 초록집 Vol.2018 No.0
최근 저유가 상황으로 인해 바이오연료의 가격경쟁력이 하락함에 따라 이를 보완하기 위해 바이오연료와 고부가 화학제품을 동시에 생산하는 공정에 관한 연구가 활발히 수행되고 있다. 본 연구에서는 corn stover의 화학적 촉매전환을 통한 바이오연료 생산 공정(cCTF 공정)과 글리세롤의 전기화학적 촉매전환을 통한 화학제품 생산 공정(eGTC 공정)을 포함하는 통합공정을 개발하고 그 경제성을 평가하였다. 연간 701,000 톤의 corn stover와 127,000 톤의 글리세롤을 원료로 74,100 톤의 바이오연료(jet fuel range alkenes)와 83,000 톤의 화학제품(glyceric acid, glyceraldehyde, hydroxypyruvic acid)을 생산하는 상용규모의 통합공정 설계안을 제시한다. 전환과정에서 수소가 이용되고 다량의 폐열이 발생하는 cCTF 공정과 부산물로 수소가 발생하고 분리 공정에서 다량의 열에너지가 요구되는 eGTC 공정의 물질 및 에너지 통합으로 전체공정에서의 비용이 감소하며, 통합공정에서 생산되는 바이오연료의 최소판매가격은 gasoline gallon equivalent (GGE) 당 $3.13으로 최근 3년간 바이오연료 평균 가격 $3.29/GGE보다 낮음을 확인하였다.