• Title/Summary/Keyword: bulk superconductor

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Development of the Fabrication Technology of High Tc Superconductor for Electrical Energy Storage (전기 에너지 저장을 위한 초전도 나노 합성 기술)

  • Lee, Sang-Heon
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.9
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    • pp.442-445
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    • 2006
  • In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBaCuO bulk superconductor with high mechanical strength and critical current density. In this project, the establishment of fabrication condition and additive effects of second elements were examined so as to improve the related properties to the practical use of YBaCuO superconductor, and we reported the production of the YBaCuO high Tc superconductor by the pyrolysis method.

A Femtosecond Laser Metrology on the Thermal Conductivity of a Nanoscale Superconductor Material (펨토초 레이저를 이용한 나노 스케일 초전도 재료의 열전도율 평가)

  • Kim, Yun Young
    • Journal of the Korean Society for Nondestructive Testing
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    • v.35 no.5
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    • pp.314-320
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    • 2015
  • The present study investigates the thermal characteristics of a nanoscale superconductor material. A thin-film of $YBa_2Cu_3O_7-x$ was deposited on a $SrTiO_3$ substrate by using a pulsed-laser deposition technique and characterized using an ultrafast laser system. In order to extract a thermal conductivity value, a numerical solution for a transient one-dimensional heat conduction equation was obtained using a finite-difference method. The curve-fit shows a value 1.2 W/mK, which is relatively lower than those of bulk materials. This research provides a material property of superconductor thin-film required for the thermal design of micro or nanodevices.

Development of Ceramic Superconductor Bulk for Electric Energy resonance (초전도 화합물 세라믹 벌크 개발)

  • Lee, Sang-Heon;Choi, Yong
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.42-43
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    • 2008
  • The numerous application of ceramic superconducting bulk such as magnetic levitation train flywheel energy, levitation transpormation, magnetic bulk magnet etc. To obtain YBaCuO materials in the form of large single crystals are necessary. A refreshment and uniform distributon of the superconducting particle in the sample. The enhancement of the critical density was ascribe to a fine dispersion of the superconducting particle.

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Fabrication of the Bulk Superconductor by Thermal Diffusion Process (열확산 프로세스에 의한 초전도 벌크 합성)

  • Lee, Sang Heon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.6
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    • pp.461-465
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    • 2021
  • A diffusion heat treatment process for YBa2Cu3O7-y bulk superconductor in a Gd2O3 powder was attempted. As a result of measuring the critical temperature of the superconducting bulk, there was no change in the superconducting transition temperature as the Gd particles diffused into the YBa2Cu3O7-y lattice, resulting in dense microstructure. As a result of measuring the critical current, the critical current density (Jc) of the superconducting bulk having treated by the Gd thermal diffusion treatment at 0 T increased to 3×104 A/cm2 at 0 T, which was higher than that of the superconducting bulk without thermal diffusion treatment. The surface magnetic force of the superconducting bulk with Gd thermal diffusion treatment was observed at the center of the superconducting bulk with the maximum trapped magnetic force (Hmax) of 1.51 kG. This result means that the Gd thermal diffusion treatment contributes to improving the critical current density Jc of YBa2Cu3O7-y, and it is believed that Gd particles migrating into the superconducting bulk through thermal diffusion either fill the surface pores of YBa2Cu3O7-y superconductors or act as a flux pinning center.

Fabrication Technology of high Tc Superconductor for Electrical Equipment (전력기기 초전도 합성기술)

  • Lee, Sang-Heon
    • The Transactions of the Korean Institute of Electrical Engineers C
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    • v.55 no.7
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    • pp.364-366
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    • 2006
  • In order to realize the commercial application of HTSC materials, it is necessary to develop the fabrication process of high Tc oxide superconductor materials with desired shape and for practical application and high critical current density as well as good mechanical strength which can withstand high lorenz force generated at high magnetic field. Much studies have been concentrated to develop the fabrication technique for high critical current density but still there are a lot of gap which should be overcome for large scale application of HTSC materials at liquid nitrogen temperature. Recently some new fabrication techniques have been developed for YBaCuO bulk superconductor with high mechanical strength and critical current density. In this project, the establishment of fabrication condition and additive effects of second elements were examined so as to improve the related properties to the practical use of YBaCuO superconductor, and we reported the production of the YBaCuO high Tc superconductor by the pyrolysis method.

[ $YBa_2Cu_3O_x$ ] Superconductor by Adding with Non-superconducting Additives

  • Soh, Dea-Wha;Cho, Yong-Joon;Natalya, Korobova
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2004.11a
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    • pp.349-352
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    • 2004
  • The improvement of critical temperature $(T_c)$, critical magnetic field $(H_c)$, and critical current density $(J_c)$ of superconductor is important for practical applications. In this study, the additives such as metal oxides were used to improve the preparation conditions of $YBa_2Cu_3O_x$ superconducting bulk samples and depending on additives the properties of $YBa_2Cu_3O_x$ superconductor were studied. The effects of additives to the density, grain alignment, and porosity of samples that affect the critical current density of superconductor also have been investigated.

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A parameter study on the pre-heat treatment for the fabrication of a large grain YBCO bulk superconductor without intermediate grinding step

  • Hong, Yi-Seul;Kim, Chan-Joong;Lee, Hee-Gyoun
    • Progress in Superconductivity and Cryogenics
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    • v.22 no.1
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    • pp.1-6
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    • 2020
  • This is a parameter study for the direct fabrication of a large grain YBCO bulk superconductors using Y2O3, BaCO3 and CuO powders without any grinding step. The cracks, which have been formed due to volume contraction during calcination step, have been prevented by controlling the heating rate at 930~950 ℃. It has been observed that multi-grain growth has occurred due to the dissolution of Sm123 seed due to the retention of carbon in Ba-Cu-O melt. In order to accelerate the carbon release in prior calcination heat treatment, the reduction of pellet thickness and the drilling of artificial holes have been applied. Single-grain YBCO bulk superconductor has been successfully fabricated by stacking multiple thin slab. However, the crack formation has been rather prominent for the compact with artificial holes. The use of buffer pellet, which is supposed to act as diffusion barrier, has prevented the dissolution of Sm123 seed crystal and has led to the growth of single grain of high content of carbon containing specimen.

Quasi-static Characteristics in Radial Direction of 100 kWh Class Superconductor Bearing (100 kWh급 초전도 베어링의 지름방향 준정적 특성)

  • Jung, S.Y.;Park, B.J.;Han, Y.H.;Park, B.C.;Lee, J.P.;Han, S.C.
    • Progress in Superconductivity
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    • v.12 no.1
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    • pp.27-31
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    • 2010
  • A superconductor flywheel energy storage system (SFES) is an electro-mechanical battery which transforms electrical energy into mechanical energy for storage, and vice versa. Many aspects of the quasi-static behavior of flywheel rotors still need to be studied closely, and the rotors require a stable and highly efficient supporting system such as high temperature superconductor (HTS) bearings, which offer dynamic stability without the use of active control. Quasi-static properties of HTS bearings in the radial direction provide data to solve problems which may occur in a running system. Since stiffness in countering rotor vibration is the main parameter for designing an HTS bearing system, we investigated the quasi-static properties of the magnetic force between permanent magnets(PMs) and HTS bulks in the radial direction. We measured radial stiffness, and discovered that bearing stiffness varied greatly depending on the number of active HTS bulks. This is valuable data for predicting the change in stiffness during partial HTS bearing failure. The quasi-static test results are used for optimal design and performance prediction for the 100 kWh class superconductor bearing.

Neutron Irradiation Effect of YBa2Cu3O7-y Superconductor (YBa2Cu3O7-y 초전도 벌크의 중성자 조사 효과)

  • Lee, Sang Heon
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.34 no.6
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    • pp.438-441
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    • 2021
  • The electrical characteristics of single-crystal composite superconductors produced by a melting process were studied by neutron irradiation. In order to improve the current characteristics of the YBa2Cu3O7-y superconductor, it is necessary to form an effective flux pinning center inside the superconductor. In this study, an increase in flux pinning was attempted through neutron irradiation onto YBa2Cu3O7-y superconductors. The neutron irradiation was performed at 30 MeV for 500 sec, The electrical properties of the superconductors were measured in a magnetic field of 5 Tesla at 50 K using a magnetic properties measurement system (MPMS). After neutron irradiation, the critical current density of the YBa2Cu3O7-y superconductor in a 1 Tesla magnetic field was 1×105 A/cm2. Once neutrons were irradiated at 30 MeV and 10 μA for 500 sec, the critical current density was observed to increase significantly. When neutrons are irradiated to a superconductor, micro-defects are created in the superconductor, and they act as flux pinning centers that hold the magnetic field generated when an electric current flows.