• 제목/요약/키워드: Kim Sang-Ik

검색결과 1,125건 처리시간 0.03초

Three Dimensional Analysis of Device Cell Structure

  • Hyung-Ho ppark;Hyung-Mun Kim;Hee-Tae Lee;Sahn Nahm;Sang-Gi Kim;Joong-Whan Lee;Byong-Hwa Koak;Kyoung-Ik Cho;Young-Il Kang
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 1993년도 제5회 학술발표회 논문개요집
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    • pp.89-90
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    • 1993
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Effect of Mechanical Alloying on Combustion Densification of MoSi$_2$

  • Park, Hyung-Sang;Park, Jin-Seong;Ka, Mi-da;Shin, Kwang-Seon;Kim, Yong-Seong
    • 한국분말재료학회지
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    • 제5권4호
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    • pp.312-318
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    • 1998
  • The effect of the mechanical alloying of elemental Mo and Si powders on the combustion densification behavior of MoSi$_2$ was investigated. The ignition temperature of the combustion reaction of the mechanically alloyed powder was measured to be significantly lower than that of the powder mixture prepared by the low energy ball milling process. The densification of the products after the combustion reaction under compressive pressure from the mechanically alloyed powders, however, was found to be poorer than that of the products from the ball milled powder.

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배전전주의 봉상 접지전극 형태별 임피던스 특성의 모델링 (Modeling of Impedance Characteristics of Grounding Electrode for Distribution Line Pole)

  • 심건보;김경철;이형수;박재덕;최종기;박상만
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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    • pp.694-696
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    • 2005
  • Although DC ground resistance is a good index of grounding performance for grounding electrodes, it does not reflect the grounding performance during transient state. Besides, impulse ground impedance, which is defined by a ratio of the peak value of transient ground potential rise to the peak value of impulse current, cannot be an absolute index due to its dependence on impulse current shape. In this paper, ground impedance characteristics of ground electrodes has been measured in frequency domain ranging from 1 Hz to hundreds of kHz. Equivalent circuit models and transfer function models of the ground rod have been identified from the measured values of ground impedance in frequency domain.

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세라믹 패키지를 이용한 표면실장형 다이오드의 제작과 특성평가 (Manufacture of Surface Mounted Device Type Fast Recovery Diode with Ceramic Package)

  • 전명표;조상혁;한익현;조정호;김병익;유인기
    • 한국전기전자재료학회논문지
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    • 제20권5호
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    • pp.415-420
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    • 2007
  • Generally, a diode package consists of the synthetic resin that has good durability but low thermal conductivity. The surface mounted type fast recovery diode was fabricated by using ceramic package. Its main manufacture processes are composed of soldering, sillicon coating and side termination. And it has various advantages that diode is small, easy manufacture and fast cooling. The electric characteristics of the diode such as reverse recovery time, breakdown voltage, forward voltage, and leakage current were 5.28 ns, 1322 V, 1.08 V, $0.45\;{\mu}A$, respectively.

초고압 GIS 접지시스템에서 낙뢰 및 고장에 의한 과도특성 해석 (Transient Characteristics of GIS Grounding Systems by Lightning and Fault)

  • 이형수;심건보;김정훈;정상진
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 1995년도 추계학술대회 논문집 학회본부
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    • pp.77-79
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    • 1995
  • In performing lightning and fault studies in GISs, it is of great importance to accurately model the conductor network consisting of the grounding systems and overhead conductor structures. In particular, the overhead grounded pipe enclosures of the GIS should be appropriately modelled. In this paper, the overhead pipe enclosures of a 500 kV $SF_6$ breaker and substation grounding system are presented in detail. During a phase-to-ground fault, scalar potentials and electromagnetic fields are computed at different frequencies for various conductor network configurations is defined by varying the number of conductors used to represent the pipes at different frequencies are obtained. Such knowledge will be very useful in reducing computation time for a transient ground potential rise study which will be performed in the future.

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