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온실가스 고려 유무에 따른 근해어업의 업종별 생산성 변화 비교분석
전용한(Yong-Han Jeon),남종오(Jong-Oh Nam) 한국해양비즈니스학회 2021 해양비즈니스 Vol.- No.49
As carbon neutral has emerged as a new paradigm for climate change globally, this study aims to analyze productivity changes in offshore fisheries with or without consideration of greenhouse gas(GHG) emissions and to present policy implications. As an analysis method, the Global Malmquist Luenberger productivity index and the Global Malmquist productivity index were used to analyze and compare the productivity by year and by fishery for offshore fisheries. In addition, the Mann-Whitney U test was adopted to see if the difference in productivity was statistically significant. As a result of the analysis, firstly the cumulative productivity increased by 4.3% excluding GHG emissions, but decreased by 3.89% including GHG emissions. Second, the cross-period average productivity rose 0.85% except for GHG emissions, but fell 0.79% containing GHG emissions. Third, the productivity of 13 gears in offshore fisheries decreased by 0.03∼7.3% including GHG emissions, and the differences in each gear’s productivity with or without consideration of GHG emissions were statistically significant within 10% significance level. Based on the analysis results, it was suggested that the new fishing vessel project, development of electric hybrid fishing vessels, and fishing vessel reduction project should be implemented to improve the productivity of offshore fisheries.
전용현(Yong-Hyun Jeon),박일한(Il-Han Park),김영선(Young-Sun Kim),김홍정(Hong-Jung Kim) 대한전기학회 2009 대한전기학회 학술대회 논문집 Vol.2009 No.7
본 논문은 매입형 영구자석 동기모터(IPMSM)의 제어 파라미터에 관한 것으로, 종래의 IPMSM의 제어는 120˚ 통전방식의 인버터로 구동되는 구형파 제어를 적용하여 왔으나, 최근 정음화, 저진동화 및 고속 운전영역의 확대 등의 시장의 요구, 제어 기술의 발전으로 정현파 제어 (또는 벡터 제어) 방식이 점차로 확대되는 추세이다. 본 논문에서는 정현파 제어방식에 요구되는 IPMSM의 모터 파라미터에 대해 FEM 해석 결과와 측정 장치에 의한 실측의 결과를 비교 분석하여, IPMSM의 제어 파라미터 도출의 기초 연구 자료로 활용하고자 한다.
비등 열전달 시스템의 안정성 향상을 위한 탄소나노튜브 코팅의 열전달 및 내구성에 대한 연구
전용한,김영훈,김남진,Jeon, Yong-Han,Kim, Young-Hun,Kim, Nam-Jin 대한안전경영과학회 2017 대한안전경영과학회지 Vol.19 No.1
In this study, we investigated to the heat transfer performance of coating nano-structure with various shapes and patterns on the heat transfer surface. As a result of the measurement of the 3D nano shape, it was confirmed that the roughness generally increases when the adhesive is sprayed on the coating surface and finished durability experiment. In the case of TEOS adhesive, the roughness increased by $0.074{\mu}m$, $0.012{\mu}m$ and $0.015{\mu}m$, and the contact angle decreased $12.64^{\circ}$, $1.31^{\circ}$, $9.84^{\circ}$ at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of PVA adhesive, the roughness increased by $0.069{\mu}m$, $0.056{\mu}m$ and $0.03{\mu}m$, and the contact angle decreased $2.85^{\circ}$, $4.82^{\circ}$, $6.96^{\circ}$ at the coating time of 120 seconds, 180 seconds and 240 seconds, respectively. In the case of DGEBF adhesive, the roughness increased by $0.042{\mu}m$, $0.053{\mu}m$ and $0{\mu}m$, and the contact angle decreased $0.81^{\circ}$ at the coating time of 120 seconds, increased $4.82^{\circ}$, $6.96^{\circ}$ at the coating time of 180 seconds and 240 seconds, respectively. As a result, the durability tends to decrease as more nano-structures are deposited, and 3D nano shapes, contact angles and SEM photographs showed that the performance of the PVA adhesive was superior among the three adhesives.
천연가스 고체수송 및 저장을 위한 가스 하이드레이트 상평형 조건에 대한 연구
전용한(Yong-Han Jeon),김종윤(Jong-Yoon Kim),김종보(Chong-Bo Kim),김남진(Nam-Jin Kim) 대한설비공학회 2008 설비공학 논문집 Vol.20 No.4
Natural gas hydrates are ice-like solid substances, which are composed of water and natural gas, mainly methane. They have three kinds of crystal structures of five polyhedra formed by hydrogen-bonded water molecules, and are stable at high pressures and low temperatures. They contain large amounts of organic carbon and widely occur in deep oceans and permafrost regions. Therefore, they are expected as a potential energy resource in the future. Especially, 1 ㎥ natural gas hydrate contains up to 172 N ㎥ of methane gas, depending on the pressure and temperature of production. Such large volumes make natural gas hydrates can be used to store and transport natural gas. In this study, three-phase equilibrium conditions for forming natural gas hydrate were numerically obtained in pure water and single electrolyte solution containing 3 wt% NaCl. The results show that the predictions match the previous experimental values very well, and it was found that NaCl acts as an inhibitor. Also, help gases such that ethane, propane, i-butane, and n-butane reduce the hydrate formation pressure at the same temperature.
전용한(Jeon, Yong-Han),김종윤(Kim, Jong-Yoon),김남진(Kim, Nam-Jin),임경범(Lim, Kyung-Bum),서영호(Seo, Young-Ho),김기환(Kim, Ki-Hwan) 한국산학기술학회 2011 한국산학기술학회논문지 Vol.12 No.8
본 연구에서는 가스터빈과 증기터빈, 열회수증기 발생 장치와 지역난방 열교환기로 열병합 발전 시스템을 구성하여 복수기가 없이 증기 터빈 중압단에서 추기된 증기와 배기 증기를 지역난방 열교환기의 열원으로 사용하는 추기 배압식을 적용하였다. 구성된 시스템에 대하여 필요로 하는 열부하량과 발전 출력 조건을 만족 시키기 위한 최 적 설계 성능 해석을 하였으며, 이와 함께 겨울철 외기 온도 조건의 변화에 대한 시스템의 부분부하 해석을 하였다. 해석을 위해 상용 프로그램인 Thermoflex를 사용하였다. 시스템의 해석 결과, 기준 조건에서 수요처의 요구를 만족 시키는 최적 설계를 기준으로 각 외기 온도 변화에 대한 부분부하 성능 해석의 결과를 얻을 수 있었다. 그 결과 열부하량이 고정된 상태에서, 가스터빈과 전체 시스템의 출력 은 외기온도가 감소함에 따라서 증가하였지만, 열원인 배기가스의 온도 감소로 인하여 증기터빈의 출력은 이와 반대 로 감소하는 경향을 나타내었다. 그러나 전체 시스템에서 가스터빈의 차지하는 비중이 크기 때문에 전체 시스템의 출 력의 경향은 가스터빈과 동일한 결과를 얻을 수 있었다. The co-generation system consisted of gas a turbine, a steam turbine, heat recovery steam generator and a heat exchangers for district heating was investigated in the present study. A back-pressure steam turbine (non-condensing type) was used. A partial load analysis according to the outdoor temperature in winter was conducted and optimal thermal load and power conditions was examined using the commercial computing software Thermoflex. As a result, under a constant thermal load, the power outputs of gas turbine and overall system increased as an outdoor temperature decreased. On the other hand, the reduction in exhaust gas temperature led to the decrease in output of steam turbine. Considering the portion of gas turbine in overall system in terms of the power output, it can be known that the tendency in power output of overall system was similar to that of the gas turbine.
도로터널 화재시 반횡류식 균일배기 환기방식에서의 최적배연 연구
전용한(Yong-Han Jeon),유지오(Oh-Ji Yoo),김남진(Nam-Jin Kim),서태범(Tae-Boem Seo),김종윤(Jong-Yoon Kim) 대한설비공학회 2009 설비공학 논문집 Vol.21 No.3
In this study it is intended to review the moving characteristics of smoke by performing visualization for calculation of the optimal smoke exhaust air volume in case a fire occurs in tunnels where transverse ventilation is applied, and to obtain basic data necessary for design of the smoke exhaust systems by deriving optimal smoke exhaust operational conditions under various conditions. As a result of this study, if it was assumed 0 critical velocity in the tunnel, the smoke exhaust air volume was limited within 250 meter in the road-tunnel disaster prevention indicator and the exhaust efficiency was from 55.1% to 95.8% in the result of this study. In case of oversized exhaust ports, the generated smoke is more than the case of uniform exhaust. When the critical velocity in the tunnel is 1.75 ㎧ and 2.5 ㎧, the optimal smoke exhaust air volume has to be more than 173 ㎥/s, 236 ㎥/s for the distance of the moving smoke which can limit the distance to 250m.