• Title/Summary/Keyword: 상부 임계 자장

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Numerical Analysis on the Heat Transfer Characteristics of Benard Flow in a Magnetic Fluids (자성유체의 Benard 유동에서 열전달특성에 관한 수치적 연구)

  • Park, J.W.;;Seo, L.S.;Jun, C.H.;Kim, Y.S.
    • Journal of the Korean Magnetics Society
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    • v.13 no.1
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    • pp.41-46
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    • 2003
  • This study deals with the Benard flow of magnetic fluids in a rectangular cavity. The ratio of height to length of the cavity is 1 : 4 and the bottom of the cavity is assumed to be a heating face while the other sides are to be cooling faces. When magnetic field was equally impressed, considering the internal rotation of the elementary ferromagnetic particle, we found the following result from the numerical analysis of the GSMAC algorithm applied to the equations for the magnetic fluid. Benard flow was controled by the intensity and the direction of magnetic fields, and a critical point was appeared when the magnetic field near H=-7000 was applied.

Microstructure and Critical Current Density of $Nb_3$Sn wire processed by Internal Tin Method (내부확산법으로 제조한 $Nb_3$Sn선재의 미세조직 및 임계전류밀도특성)

  • 김상철;오상수;하동우;하홍수;류강식;권해웅
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.11 no.11
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    • pp.1022-1026
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    • 1998
  • The mutifilamentary $Nb_3$Sn wire containing 135 Nb filaments was manufactured by the internal tin method. The critical current density ($J_C$) in magnetic fields for the wires heat-treated at $660^{/circ}C$ and $700^{/circ}C$ were investigated. The Non-Cu $J_C$ and n-value of 0.82 mm$\phi$ $Nb_3$Sn wire heat-treated at $700^{/circ}C$ for 240 hours was approximately 450 A/$mm^2$ at 12T, 4.2K and 14, respectively. Also the $B_{C2}$ of $Nb_3$Sn wire extrapolated by Kramer plot was 27.2T. The wire heat-treated at $700^{/circ}C$ for 240 hours showed smaller residual tin concentration in the matrix and the larger area of $Nb_3$Sn layer as comparison with the wire heat-treated at $660^{/circ}C$.

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