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Kim, Hae-Joon;Cho, Jeon-Wook;Sim, Ki-Deok;Kim, Jae-Ho;Kim, Seok-Ho;Jang, Hyun-Man;Lee, Soo-Gil
- Progress in Superconductivity and Cryogenics
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- v.9 no.4
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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.
https://doi.org/10.9714/psac.2007.9.4.041 인용 PDF KSCI

Zhang P.;L., Qi S.;Z., Wang R.
- Progress in Superconductivity and Cryogenics
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- v.10 no.4
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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.
https://doi.org/10.9714/psac.2008.10.4.001 인용 PDF KSCI

Sohn, Hyung-Hwan;Min, Chi-Hyun;Lee, Eon-Yong;Sim, Ki-Deok;Kim, Seok-Ho;Seong, Ki-Chul
- Proceedings of the KIEE Conference
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- 2006.07b
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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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