• 제목/요약/키워드: Intermediate phase

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Fabrication of BSCCO High Tc Superconducting Precursor (BSCCO 초전도 전구체의 합성)

  • Lee, Sang-Heon;Lee, Young-Hie
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.1964-1965
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    • 2005
  • A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_Y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at $400^{\circ}C$ and calcination at $840^{\circ}C$ for 4h, the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factro in determining whether it is easy to form the high Tc phase or not, because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Fabrication of BSCCO High Tc Superconducting Precursor (BSCCO 초전도 전구체의 합성)

  • Lee, Sang-Heon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.290-291
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    • 2005
  • A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_Y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at $400^{\circ}C$ and calcination at $840^{\circ}C$ for 4h. the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factor in determining whether it is easy to form the high Tc phase or not. because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Fabrication of High Tc Superconductor Using Thermal Pyrolysis (열분해법에 의한 고온 초전도 합성)

  • Lee, Sang-Heon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2006.06a
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    • pp.85-86
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    • 2006
  • A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at $400^{\circ}C$ and calcination at $840^{\circ}C$ for 4h, the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factro in determining whether it is easy to form the high Tc phase or not, because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Electric Perperties of Superconductor Using Pyrolysis Methods (열분해법에 의한 초전도체의 전기적 특성)

  • Lee, Sang-Heon;Lee, Young-Hie
    • Proceedings of the KIEE Conference
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    • 2005.11a
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    • pp.79-80
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    • 2005
  • The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important fact in determining whether it is easy to form the superconducting phase or not, because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Synthesis of YBCO Superconducting Precursor using Organic metal salts method for Electric power transmission (유기금속염을 이용한 전력 전송용 YBCO 초전도 전구체 합성)

  • Lee, Sang-Heon
    • Proceedings of the KIEE Conference
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    • 2005.07c
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    • pp.1966-1967
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    • 2005
  • The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important fact in determining whether it is easy to form the superconducting phase or not, because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Optical Phase Properties of Small Numbers of Nanoslits and an Application for Higher-efficiency Fresnel Zone Plates

  • Kim, Hyuntai;Lee, Seung-Yeol
    • Current Optics and Photonics
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    • v.3 no.4
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    • pp.285-291
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    • 2019
  • We have studied the behavior of light in the intermediate regime between a single nanoslit and an infinite nanoslit array. We first calculated the optical characteristics of a small number of nanoslits using finite element numerical analysis. The phase variance of the proposed nanoslit model shows a gradual phase shift between a single nanoslit and ideal nanoslit array, which stabilizes before the total array length becomes ${\sim}0.5{\lambda}$. Next, we designed a transmission-enhanced Fresnel zone plate by applying the phase characteristics from the small-number nanoslit model. The virtual-point-source method suggests that the proposed Fresnel zone plate with phase-invariant nanoslits achieves 2.34x higher transmission efficiency than a conventional Fresnel zone plate. Our report describes the intermediate behaviors of a nanoslit array, which could also benefit subwavelength metallic structure research of metasurfaces.

Particle Agglomerate Effect on Intermediate/Final Microstructure (입자 응집이 중기/말기 미구조에 미치는 영향)

  • 손영돈;전병세
    • Journal of the Korean Ceramic Society
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    • v.29 no.11
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    • pp.843-850
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    • 1992
  • The purpose of this study was to describe the heterogeneity effects on Intermediate/Final microstructure in isothermal liquid phase sintering. Several kinds of pore shapes were made by the different in the heterogeneity stress level during Intermediate/Final stage. Specimen with 48% green density especially showed that the local regions of a sintered compact were subject to more rapid shrinkage than the surroundings. This densification limiting factors generally inhibited sintering and made the large isolated crack-like pore in heterogeneous microstructures.

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A Study on the Fabrication of Superconductor Using Pyrolysis Methods for Electric power Machinery (열분해법에 의한 전력기기용 초전도 합성 기술에 관한 연구)

  • Lee, Sang-Heon;Lee, Young-Hie
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.11a
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    • pp.153-154
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    • 2005
  • A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_Y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at 120$^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at 400$^{\circ}C$ and calcination at 840$^{\circ}C$ for 4h, the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factro in determining whether it is easy to form the high Tc phase or not, because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

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Synthesis of high functional Superconducting Precursor using Organic metal salts method for Electric power transmission (유기금속염을 이용한 고효율 전력 전송용 초전도 전구체 합성)

  • Lee, Sang-Heon
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2005.07a
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    • pp.270-271
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    • 2005
  • A high Tc superconducting with a nominal composition of $Bi_2Sr_2Ca_2Cu_3O_Y$ was prepared by the citarte method. The solid precursor produced by the dehydration of the gel at $120^{\circ}C$ for 12h is not in the amorphous state as expected but in a crystalline state. X-ray diffraction peaks of nearly the same angular position as the peaks of high Tc phase were observed in the precursor. After pyrolysis at $400^{\circ}C$ and calcination at $840^{\circ}C$ for 4h, the (001)peak of the high Tc phase was cleary observed. Experimental results suggest that the intermediate phase formed before the formation of the superconducting phase may be the most important factro in determining whether it is easy to form the high Tc phase or not. because the nucleation barriers of the two superconducting phase may be altered by the variation of the crystal structures of those intermediate phase.

  • PDF