• 제목/요약/키워드: cryogenics

검색결과 1,657건 처리시간 0.018초

AC loss comparison of Bi-2223 and coated conductor HTS tapes under bending

  • Kim, Hae-Joon;Cho, Jeon-Wook;Sim, Ki-Deok;Kim, Jae-Ho;Kim, Seok-Ho;Jang, Hyun-Man;Lee, Soo-Gil
    • 한국초전도ㆍ저온공학회논문지
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    • 제9권4호
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    • pp.41-45
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    • 2007
  • Superconductor is developed for applications in high-power devices such as power-transmission cables, transformers, motor and generators. In such applications, HTS tapes are subjected to various kinds of stress or strain. AC loss is also important consideration for many large-scale superconducting devices. In the fabrication of the devices, the critical current $(I_c)$ of the high temperature superconductor degrades due to many reasons including the tension applied by bending and thermal contraction. These bending or tension reduces the $I_c$ of superconducting wire and the $I_c$ degradation affects the AC loss of the wire. The $I_c$ degradation and AC loss (self field loss) of Bi-2223 HTS and Coated conductor were measured under tension and bending conditions at 77K and self-field.

Flow boiling of liquid nitrogen in narrow annular channels

  • Zhang P.;L., Qi S.;Z., Wang R.
    • 한국초전도ㆍ저온공학회논문지
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    • 제10권4호
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    • pp.1-5
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    • 2008
  • Flow and heat transfer characteristics of liquid nitrogen in narrow annular channels are very important for many practical applications. In the present study, the experimental investigation of flow boiling of liquid nitrogen in narrow annular channels with gap size of 0.2 and 0.5 mm is carried out. The pressure drop and heat transfer coefficients are experimentally measured. The comparison of the theoretical models for the pressure drop and the correlations of the flow boiling to the experimental results are carried out.

고온초전도 접합도체들의 I-V 특성에 관한 연구 (I-V Characteristics of HTS Conductors with Joints)

  • 손명환;민치현;이언용;심기덕;김석호;성기철
    • 대한전기학회:학술대회논문집
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    • 대한전기학회 2006년도 제37회 하계학술대회 논문집 B
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    • pp.679-680
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    • 2006
  • Various different types of joining between High Tc superconducting(HTS) tapes were prepared and current-voltage(I-V) characteristic curves were investigated at 77 K, liquid nitrogen temperature. Two typos of HTS tapes wore used, one is no laminated tape(Sumitomo high strength type tape) and the other stainless steel laminated tape(AMSC(American Superconductors Inc.) 3ply tapes) Sample joints were lap-jointed with indium or solder. Joint resistances between Sumitomo tapes with 4-10 mm in length were estimated from I-V curves and in the range of $4-8n{\Omega}$ at 77 K. Joint resistances of AMSC tapes were in the range of $140-170n{\Omega}$, much higher than them of Sumitomo samples. The n-values of jointed HTS tapes were 50% of them with no joint. In AMSC tapes, indium is better than solder as the jointing material.

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맥동관 냉동기

  • 남관우
    • 한국초전도저온공학회지:초전도와저온공학
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    • 제9권1호
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    • pp.19-25
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    • 2007
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