• Title/Summary/Keyword: PowerInte

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AFastComputationAlgorithmfortheImpedancecalculationofthePowerDistributionPlaneUsingtheTransmissionMatrix (전송선로행열을이용한전력배분기판에대한빠른임피던스계산방법)

  • Suh Young-Suk
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.54 no.6
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    • pp.251-254
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    • 2005
  • Animpedancecalculationmethodfortheirregularshapedpowerdistributionnetworksispresented.Theirregularshapedmetal-dielectric-metalboardissplitintothreepieceofsegmentstocalculatetheimpedancebetweenthetwoseparatedpointsontheboard.Transmission-matrixdescriptioncorrespondingtotheunitcolumnofboardandtheconnectionofunitcolumnboardareintroduced.Thenthetransmission-matrixfortheeachsegmentiscalculatedandreducedtothe2-portsimpedancematrix.Theproposedalgorithmisveryfastcomparingtheexistingmethods.Appliedtothe6inchby5inchsizeirregularshapedboard,theproposedmethodshows15timesfasterthantheelectromagneticorcircuitanalysismethod.

Active Optical Logic Devices Using Surface-emitting Microlasers (표면광 마이크로 레이저를 이용한 능동형 광 논리 소자의 동작 특성)

  • 유지영
    • Korean Journal of Optics and Photonics
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    • v.4 no.3
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    • pp.294-300
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    • 1993
  • Monolithic NOR and INVERTER active optical logic devices inte- grated with surface-emitting microlasers, heterojunction photo- transistors(HPT) in parallel and resistors in series are characterized. The differential quantum efficiency of the typical AlGaAs superlattice microlaser integrated in the active optical logic devices is 15%. Current gain of the HPT is 57, when emitter-collector voltage and input optical power are 4 V and $50{\mu}W$, respectively. $57{\mu}W$ of output power from the active optical logic device decreases to zero when $47{\mu}W$ of input optical power is incident on the HPT part of the active logic device.

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Large-eddy simulation on gas mixing induced by the high-buoyancy flow in the CIGMAfacility

  • Satoshi Abe;Yasuteru Sibamoto
    • Nuclear Engineering and Technology
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    • v.55 no.5
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    • pp.1742-1756
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    • 2023
  • The hydrogen behavior in a nuclear containment vessel is a significant issue when discussing the potential of hydrogen combustion during a severe accident. After the Fukushima-Daiichi accident in Japan, we have investigated in-depth the hydrogen transport mechanisms by utilizing experimental and numerical approaches. Computational fluid dynamics is a powerful tool for better understanding the transport behavior of gas mixtures, including hydrogen. This paper describes a Large-eddy simulation of gas mixing driven by a high-buoyancy flow. We focused on the interaction behavior of heat and mass transfers driven by the horizontal high-buoyant flow during density stratification. For validation, the experimental data of the Containment InteGral effects Measurement Apparatus (CIGMA) facility were used. With a high-power heater for the gas-injection line in the CIGMA facility, a high-temperature flow of approximately 390 ℃ was injected into the test vessel. By using the CIGMA facility, we can extend the experimental data to the high-temperature region. The phenomenological discussion in this paper helps understand the heat and mass transfer induced by the high-buoyancy flow in the containment vessel during a severe accident.