통합 검색 | Korea Science

강준선;이준호;나완수;박일한;권영길;손명환;김석환
- 한국초전도저온공학회:학술대회논문집
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- 한국초전도저온공학회 2002년도 학술대회 논문집
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- pp.274-276
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- 2002
To enhance the critical current of superconducting coil, the magnetic field experienced by superconductors in a coil should be minimized. This is true for both low $T_{c}$ and high $T_{c}$ superconductors, and the difference between the two lays in their isotropic/an-isotropic characteristics. In this paper, we propose a shape optimization algorithm to reduce radial magnetic field components in HTS solenoid to enhance the critical current of a solenoid. In the algorithm, finite element method and continuum shape design sensitivity formula were employed. The objective function is to minimize the maximum radial magnetic fields in a solenoid with a constraint of constant solenoid volume condition. In this paper, the details on algorithm are introduced and the calculated optimized shapes are presented.
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홍인기;황현석;한영희;성태현;노광수
- 한국초전도저온공학회:학술대회논문집
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- 한국초전도저온공학회 2002년도 학술대회 논문집
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- pp.17-19
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- 2002
Melt textured YBCO superconductors were fabricated by the top seeding method using Sml.8($Sm_{1.8}$ $Ba_{2.4}$ $Cu_{3.4}$$O_{7-Y}$) seed. We investigated the twin structures using the optical microscope, SEM and TEM. The twin structures formed during the tetragonal to orthorhombic transition which occurred at $450^{\circ}C$ in sample oxygen annealing. The twin structures were clearly observed by SEM due to the chemical etching effects. The lengths of twin structures were increased as the oxygenation heat treatment time increased from 1hr to 10hr. We investigated twin structure by TEM. The twin spaces were considered to be related to the oxygen contents. The results suggested an oxygen diffusion model for the formation of the twin lengths.
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