• Title/Summary/Keyword: Choi Chang Hak

검색결과 278건 처리시간 0.027초

A Development and Performance Assessment of On-Line Monitoring System for Optical Fiber Composite Underground Distribution Network using DTS (DTS를 활용한 광복합 지중 배전계통 실시간 감시시스템 개발 및 성능평가)

  • Cho, Jin-Tae;Kim, Ju-Yong;Lee, Hak-Ju;Cho, Hwi-Chang;Choi, Myeong-Ho
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • 제25권6호
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    • pp.115-121
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    • 2011
  • Intelligent distribution equipment is inevitable to realize self-healing which is one of smart grid functions in distribution network. Therefore, most of distribution equipment have been developed with self diagnostic sensors. However, it is not effective to construct on-line monitoring system for underground distribution cable because of high cost and low sensitivity. Recently, optical fiber composite cable is being considered for communication and power delivery in order to cope with increasing communication in distribution network. This paper presents the design and performance assessment results of underground cable on-line monitoring system using DTS(Distributed Temperature Sensing) and optical fiber composite underground cable.

Effect of Molecular Structure on Liquid Crystalline Properties (1); 1,10-Bis(p-2-,3-,4,-halogenophenoxycarbonyl)phenoxydecane (액정성에 대한 분자 구조의 효과 (1); 1,10-Bis(p-2-,3-,4-halogenophenoxycarbonyl)phenoxydecane)

A Study on the Energy Saving Strategy in Electric Railway System (직류 전기철도 에너지 절감방안 연구)

  • Choi Byung-Woon;Chang Sang-Hoon;Kim Hak-Ryun
    • Proceedings of the KSR Conference
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    • 한국철도학회 2005년도 추계학술대회 논문집
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    • pp.676-681
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    • 2005
  • The regenerative braked cars are being introduced in DC electric railway for energy saving. There has been a recent tendency for DC traction substation with regenerative inverter to increase in number. This is strongly related to the desire for effective utilization of electric power regenerated by DC electric cars and to the aim ensuring stable operation of regenerative braking system. The regenerative inverters DC power feed back from a generative car into AC power at a substation and supplies it to distribution lines. This paper suggest the result of characteristic analysis and capacity simulation. economical analysis in the regenerative inverter system.

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Designing Electronics for High Frequency Shock (고주파 충격에 의한 전자부품 고장 방지 설계)

  • Lee, Jong-Hak;Kang, Dong-Seok;Choi, Ji-Ho;Kang, Young-Sik;Lee, Chang-Min
    • Transactions of the Korean Society for Noise and Vibration Engineering
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    • 제25권10호
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    • pp.700-706
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    • 2015
  • In this study, stability designing electronics mounted on launch vehicle for shock load(low/high frequency band) could be derived. For the low-frequency shock loads, CCA(circuit card assembly) has secured the structural integrity over the best natural frequency techniques. For the high-frequency shock load, the structural integrity could be ensured with applying device such as the insulation pad. When the EAR is applied, insulation effect of part application is good more than whole application.

The Energy Production of Offshore Wind Farm Using WindPRO (WindPRO를 이용한 해상풍력단지 발전량 예측)

  • Jeong, Moon-Seon;Moon, Chae-Joo;Kwak, Seung-Hun;Choi, Man-Su;Chang, Young-Hak
    • Proceedings of the KIPE Conference
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    • 전력전자학회 2010년도 추계학술대회
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    • pp.267-268
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    • 2010
  • 본 논문에서는 풍력발전단지 설계를 목적으로 사용되고 있는 EMD사의 WindPRO2.6을 이용하여 서남해안에 설치된 50m 높이의 Met mast에서 1년 동안 관측된 풍황자원을 분석하고, 특정 풍력발전기를 적용하여 40MW급 해상풍력발전단지를 설계했을 경우 연간 생산되는 발전량을 예측하였다.

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Crosslinking of Electrospun Poly (VDF-co-HFP) Nanofibrous Membranes by Gamma-ray Irradiation

  • Kim, Yun-Hye;Lim, Youn-Mook;Choi, Jae-Hak;An, Sung-Jun;Park, Jong-Seok;Nho, Young-Chang
    • Journal of Radiation Industry
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    • 제2권3호
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    • pp.105-110
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    • 2008
  • Poly (VDF-co-HFP)/PEGDMA nanofibrous membranes (NFMs) have been prepared by an electrospinning process. Since electrospun NFMs have a nanoporous structure, they have a potential application for a polymer electrolyte or a separator. Poly (VDF-co-HFP) is a polymer electrolyte binder. In order to improve their mechanical properties, poly (VDF-co-HFP)/PEGDMA NFMs were crosslinked by a gamma-ray irradiation. Then the crosslinked NFMs were characterized through an electrolyte uptake, IR structural analysis, and SEM morphological investigation.

Surface Functionalization of a Fluoropolymer by Ion Beam-induced Graft Polymerization of 4-Vinyl Pyridine

  • Jung, Chan-Hee;Hwang, In-Tae;Choi, Jae-Hak;Nho, Young-Chang
    • Journal of Radiation Industry
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    • 제4권4호
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    • pp.341-345
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    • 2010
  • The surface functionalization of a fluoropolymer by ion beam-induced graft polymerization was described in this research. The surface of poly(tetrafluoroethylene) (PTFE) films were irradiated by a 150 keV $H^+$ ions, and 4-vinyl pyridine (4VP) as a functional monomer was then thermally graft polymerized on the irradiated surface. The surface properties of poly(4-vinyl pyridine) (P4VP)-grafted PTFE films were investigated in terms of grafting degree, wettability, chemical structure, and morphology. The results revealed that the surface of PTFE films was successfully functionalized by ion beam-induced graft polymerization of 4VP.

The Radiation Resistance Evaluation of Electrically Insulating Polymers

  • Lee, Dong-Hoon;Jung, Chan-Hee;Hwang, In-Tae;Choi, Jae-Hak;Im, Don-Sun;Kim, Ki-Yup;Nho, Young-Chang
    • Journal of Radiation Industry
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    • 제5권3호
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    • pp.237-242
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    • 2011
  • In this research, the radiation resistance of ethylene propylene rubber (EPR) and chlorosulfonated polyethylene (CSPE) which can be used as a insulating materials of for electrical cable in the nuclear power plant were investigated. EPR and CSPE were irradiated by ${\gamma}$-ray at various doses ranging from 50 to 500 kGy at room temperature in air. The irradiated EPR and CSPE was investigated in terms of activation energy, mechanical properties, and oxidation stability. The experimental results revealed that CSPE exhibited the higher radiation resistance in comparison to that of EPR.