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Lactobacillus casei YIT 9018 의 세포내 단백질 분해효소에 관한 연구
백영진,윤쾌병,윤영호,김현욱 ( Young Jin Back,Kyai Byung Yoon,Young Ho Yoon,Hyun Uk Kim ) 한국축산학회 1983 한국축산학회지 Vol.25 No.1
Proteinase of lactic acid bacteria plays an important role in the development of the flavor and texture in cheese and in other fermented milk products. This study was carried out to obtain the informations on the intracellular proteinase of L. casei YIT 9018. Crude proteinase from L. casei YIT 9018 was isolated and characterized. The proteinase production was markedly increased during the logarithmic growth phase. The best proteinase production of L. casei YIT 9018 was obtained in the medium containing 2% of casein. The maximum proteinase production was observed at 37℃ and at pH 7.0. The proteolytic enzyme retained 74% of its original activity after heating at 60℃ for 60 min and 58% at 90℃ after 60 min. A metal chelating agent (EDTA) evidenced vity, but monoiodoacetic acid induced about 20% inhibition. Divalent Ni, Cu, Zn and Mg ions Caused 20-30% enzyme inhibition, while manganese ions enhanced the enzyme activity slightly. Further studies are needed for purification and characterization of the proteinase of L. casei YIT 9018. In addition, studies are needed to elucidate the proteolysis of milk protein by this proteinase during manufacture and ripening of fermented dairy products.
저온 열원 HFC-134a 유기랭킨사이클의 출력 극대화
백영진(Young-Jin Baik),김민성(Minsung Kim),장기창(Ki-Chang Chang),이영수(Young-Soo Lee),나호상(Ho-Sang Ra) 대한기계학회 2011 大韓機械學會論文集B Vol.35 No.1
본 연구에서는 지열발전 등과 같은 저온 열원을 에너지원으로 하는 발전에 응용될 수 있는 HFC-134a 유기랭킨사이클의 출력 극대화를 수행하였다. 기존의 연구와는 달리, 본 연구에서는 열교환기 해석에 유한체적법을 적용함으로써 작동유체의 열전달 및 압력강하 특성을 고려하였다. 또한, 열원과 냉각수의 입구온도 및 유량, 그리고 사이클을 구성하는 열교환기들의 총 전열면적을 구속 조건으로 함으로써, 기존 연구들에 비해 보다 현실적인 결과를 얻을 수 있도록 하였다. 사이클의 출력은 3 개의 설계인자를 이용하여 최적화 하였다. 시뮬레이션 결과, 출력을 극대화 시킬 수 있는 설계인자들의 최적조합이 존재함을 보였다. 또한, 출력 향상을 위해서는 증발과정의 개선이 우선적으로 필요함을 보였다. In this study, an organic Rankine-cycle system using HFC-134a, which is a power cycle corresponding to a lowtemperature heat source, such as that for geothermal power generation, was investigated from the view point of power optimization. In contrast to conventional approaches, the heat transfer and pressure drop characteristics of the working fluid within the heat exchangers were taken into account by using a discretized heat exchanger model. The inlet flow rates and temperatures of both the heat source and the heat sink were fixed. The total heat transfer area was fixed, whereas the heat-exchanger areas of the evaporator and the condenser were allocated to maximize the power output. The power was optimized on the basis of three design parameters. The optimal combination of parameters that can maximize power output was determined on the basis of the results of the study. The results also indicate that the evaporation process has to be optimized to increase the power output.
백영진(Baik, Young-Jin),이승호(Lee, Seung Ho),김민성(Kim, Minsung),이영수(Lee, Young-Soo),장기창(Chang, Ki-Chang),나호상(Ra, Ho-Sang) 한국태양에너지학회 2012 한국태양에너지학회 학술대회논문집 Vol.2012 No.11
In this study, an annual heating performance of a seawater-source heat pump and an air-source heat pump, assumed installed in Gangneung city near the East Sea in Korea, was simulated. An annual heating load for a typical Korean-style apartment house, which has an effective area of about 85 ㎡, was modeled by using TRNSYS program. The seawater temperature was calculated from the regression equation based on the measurement. A heat pump performance at full-load was calculated from the regression equation, which involves refrigerant"s evaporating and condensing temperatures, based on a commercial compressor performance map. A part-load performance was also considered. Simulation results show that an annual heating coefficient of performance (COPH) of the seawater-source heat pump is 8.5% greater than that of an air-source heat pump.
백영진(Young-Jin Baik),장기창(Ki-Chang Chang),박성룡(Seong-Ryong Park),나호상(Ho-Sang Ra),김지영(Ji-Young Kim) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
Performance of a sea water heat source heat pump system was investigated in this study. The system was designed to perform a single stage operation in summer, as well as a cascade operation in winter to ensure the high temperature lift. A steady-state simulation model was developed to analyze and optimize its performance. The model contains compressors, expansion valves and heat exchangers. The compressors were analyzed by map-based model, while a condenser, an evaporator and a cascade heat exchanger were modeled by UA-LMTD method with a counter-flow assumption. Simulations were carried out for single stage operation together with cascade operation. The simulation results show that the sea water heat source heat pump system exhibits a COP of 4.8~5.5 in summer season along with a heating COP of 3.0~3.5 in winter season.
백영진 대한기계학회 2018 대한기계학회 춘추학술대회 Vol.2018 No.5
초임계 이산화탄소(sCO2) 발전기술의 미래 비젼 고효율, 컴팩트, Low-cost발전 시스템 구현 잠재력 재생에너지 분산발전/소형화력 분야, 석탄/가스/원자력/Syngas 등 다양한 응용분야 -> 현재의 스팀발전 및 가스발전 대체 초임계 이산화탄소 발전시스템의 기술 이슈 고속 터보기기 기술, low-leakage shaft end seals, bearings 고온/고압, low-cost 열교환기 기술 고압(300 bar)순산소 연소기술 (Direct-fired sCO2) 소재(Oxidation/corrosion performance) 기술 국내외 sCO2 발전기술 연구 추진 현황 STEP program(미국) KIER(에너지연), KIMM(기계연), KERRI(전력연), KAERI(원자력연), IAE(고기연) 등
선박 폐열 회수를 위한 초임계 이산화탄소 동력 사이클 시뮬레이션
백영진(Young-Jin BAIK),장재철(Jeachul JANG),조준현(Junhyun CHO),나호상(Ho-Sang RA),김민성(Minsung KIM) 대한기계학회 2014 대한기계학회 춘추학술대회 Vol.2014 No.11
본 연구에서는 초임계 이산화탄소 동력 사이클이 선박 주기관 폐열 회수 목적으로 적합한지를 살피기 위한 기초 연구로서, 단순 초임계 이산화탄소 브레이튼 사이클 (simple supercritical CO₂ Brayton cycle)과 캐스케이드 초임계 이산화탄소 브레이튼 사이클 (cascade supercritical CO₂ Brayton cycle)을 모델링하고, 선박 주기관 폐열 회수 조건에서 다변수 최적화 기법을 이용하여 각 사이클들의 출력을 극대화시켰다. 그 결과, 본 연구의 시뮬레이션 조건하에서 cascade cycle은 simple cycle에 비해 약 16.7% 향상된 출력을 가짐을 확인하였다. In recent years, there has been growing interest in s-CO2 (supercritical carbon dioxide) power cycle technology because of its compactness and superior efficiency. It has been also known that the s-CO2 Brayton cycle is promising in the area of renewable energy such as CSP (Concentrating Solar Power) and geothermal power generation as well as in the area of waste heat recovery, fossil fuel-fired power generation, and nuclear applications. By utilizing carbon dioxides property changes near the critical point, the compression work can be reduced, which results in a significant efficiency improvement. In this study, s-CO2 Brayton cycles for a shipboard waste heat recovery were investigated by simulation method. Both a simple and a cascade s-CO2 Brayton cycles were modeled and optimized to maximize the power. The results show that the power of a cascade s-CO2 Brayton cycle is about 16.7% greater than that of a simple s-CO2 Brayton cycle under the simulation conditions considered in the present study.
백영진,정동효,김상교,신정걸,허재관 한국낙농학회 1992 韓國酪農學會誌 Vol.14 No.4
농후발효유를 시판하고 있는 11개 회사의 28품목 중 19품목에서 분리한 효모를 가지고 Kreger-van Rij(1984), Lodder(1971) 그리고 Barnett 등(1983)의 분류방법에 따라 Candida guilliermondii, C. hellenica, C. krusei, C. lusitaniae, C. parapsilosis, C. pseudotropicalis, C. tropicalis, Hanseniaspora occidentalis, Hansenula anomala, Kluyveromyces marxianus, Pichia ohmeri, Saccharomyces cerevisiae, Sacch. dairensis, Tolulopsis candida, Torulaspora delbrueckii, T'spora. globosa의 8속, 16종으로 분류 동정하였다. In order to identify yeasts in stirred yogurts, 57 colonies of yeast were isolated from the 1.9 brands among 28 brands those were purchased from supermarket in Seoul area. Those colonies were studied on their morphological, cultural and physiological properties according to the methods of Lodder, Barnett et al., and Kreger-van Rij. Sixteen species of eight genera were identified as follows: Candida guilliermondii, C. hellenica, C. krusei, C. lusitaniae, C. parapsilosis, C. pseudotropicalis, C. tropicalis, Hanseniaspora occidentalis, Hansenula anomala, Kluyveromyces marxianus, Pichia ohmeri, Saccharomyces cerevisiae, Sacch. dairensis, Tolulopsis candida, Torulaspora delbrueckii, T'spora. globosa.