• 제목/요약/키워드: Microstructure Nonuniformity

검색결과 7건 처리시간 0.023초

Nonuniformity of Energy Absorption Capabilities of ZnO Varistors

  • He, Jin-Liang;Han, Se-Won;Cho, Han-Goo;Kang, Hyung-Boo
    • The Korean Journal of Ceramics
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    • 제4권1호
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    • pp.47-52
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    • 1998
  • The nonuniformity of energy absorption capability of ZnO varistor is systematically discussed in this paper. The nonuniformity of electrical characteristics and microstructure leads to decrease the energy absorption capability of ZnO varistor. The energy absorption capabilities were measured under different current waves, the experimental results stated that they have highly scattered phenomena. The influences of varistor surface area and nonuniformity of electrical characteristics to the energy absorption capability and the nonuniformity of commercial ZnO varistors were analyzed. There is a high nonuniformity existing in the energy absorption capability of commercial ZnO varistors.

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The Effect of Microstructure Nonuniformity on the Electrical Characteristics of ZnO Varistors with $Al_2$O$_3$ doping

  • Han, Se-Won;Cho, Han-Goo
    • KIEE International Transactions on Electrophysics and Applications
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    • 제3C권4호
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    • pp.140-145
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    • 2003
  • The influence of microstructure nonuniformity on the electrical characteristics of ZnO varistors was analyzed with the added amount of $Al_2$O$_3$ dopants. $Al_2$O$_3$ doping can effectively inhibit grain growth. When $Al_2$O$_3$ content is in the range between 0-0.1 %, the average grain size and the standard deviation decrease quickly and the grain growth is strongly inhibited. Therefore, it is possible to increase the microstructure uniformity by accurate addition of $Al_2$O$_3$ to the ZnO varistor. The breakdown voltage increases with the decrease of standard deviation. The greater the uniformity of the Zno varistor means the higher the global breakdown voltage. The $Al_2$O$_3$ dopants having about 0-0.023 wt% content can effectively improve the voltage ratio, and the voltage ratio reaches a minimum value of 2.32 at an $Al_2$O$_3$ content of 0.005 wt%.

Microstructure Characteristics of ZnO of ZnO Varistors Simulated by Voronoi Network

  • Han, Se-Won;He, Jin-Liang;Hwang, Hui-Dong;Kang, Hyung-Boo
    • The Korean Journal of Ceramics
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    • 제3권4호
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    • pp.239-244
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    • 1997
  • The Voronoi network can be used to effectively simulate the microstructure of ZnO varistors. The nonuniformity in microstructure of simulated ZnO varistor can be changed by setting different disorder degree of Voronoi network. In the region of disorder degree larger than 3 where the simulated microstructures are similar to those the actual ones of ZnO varistors, a chaotic phenomenon exists in the microstructure characteristics. This chaotic property can simulate the original behavior of nonuniformity of electrical characteristics caused by microstructures of ZnO varistors.

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The Effect of Additives on Twining in ZnO Varistors

  • Han, Se-Won;Kang, Hyung-Boo
    • The Korean Journal of Ceramics
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    • 제4권3호
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    • pp.207-212
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    • 1998
  • By comparison of the experimental results in two systems of ZnO varistors, it's appear that Sb2O3 is the indispensable element for twining in ZnO varistors and the Zn7Sb2O12 spinel acts as the nucleus to form twins. Al2O3 is not the origin of twining in ZnO varistor, but it was found that Al2O3 could strengthen the twining and form a deformation twining by ZnAl2O4 dragging and pinning effect. The inhibition ratios of grain and nonuniformity of two systems ZnO varistors increase with the increase of Al2O3 content. The twins affect the inhibition of grain growth, the mechanism could be explained follow as: twins increase the mobility viscosity of ZrO grain and grain boundary, and drag ZrO grain and liquid grain boundary during the sintering, then the grain growth is inhibited and the microstructure becomes more uniform.

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Uniformity Optimization of TFTs Fabricated on 2-shot SLS-Processed Si Films

  • Turk, Brandon A.;Wilt, P.C. Van Der;Crowder, M.A.;Voutsas, A.T.;Limanov, A.B.;Chung, U.J.;Im, James S.
    • 한국정보디스플레이학회:학술대회논문집
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    • 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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    • pp.1750-1755
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    • 2006
  • Nonoptimal placement of short-channel-length TFTs in large-grained polycrystalline Si films with a periodic microstructure, as for instance obtained via 2-shot SLS, can potentially lead to degradation in the overall uniformity of the resultant devices. In this paper, we explain and demonstrate that by simply introducing a well-defined misorientation between the devices and the periodic microstructure, it is possible to significantly reduce (and potentially entirely eliminate) the device nonuniformity problem that can arise from such a cause.

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ZnO 바리스터에서 첨가물이 쌍정에 미치는 영향 (The Effect of Additives on Twins in ZnO Varistors)

  • 한세원;조한구;강형부
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2001년도 하계학술대회 논문집
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    • pp.1057-1060
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    • 2001
  • By comparison of the experimental results in two systems of ZnO varistors, its appear that Sb$_2$O$_3$is the indispensable element for twinning in ZnO varistors, and the Zn$_{7}$Sb$_2$O$_{12}$ spinel acts as the nucleus to form twins. A1$_2$O$_3$is not the origin of twinning in ZnO varistor, but it was found that A1$_2$O$_3$could strengthen the twinning and form a deformation twinning by ZnA$_{12}$O$_4$-dragging and pinning effect. The inhibition ratios of grain growth and nonuniformity of two systems ZnO varistors increase with the increase of A1$_2$O$_3$content. The twins affect the inhibition of grain growth, the mechanism could be explained follow as : twins increase the mobility viscosity of ZnO grain and grain boundary, and drag ZnO grain and liquid grain boundary during the sintering, then the grain growth is inhibited, and the microstructure becomes more uniform.orm.m.

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Y$Ba_2$$Cu_3$$O_7$ 모서리 죠셉슨 접합의 균일성 (Uniformity of $YBa_2$$Cu_3$$O_7$ Step-edge Josephson Junctions)

  • 이순걸;황윤석;김진태
    • Progress in Superconductivity
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    • 제2권2호
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    • pp.81-85
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    • 2001
  • Uniformity of critical currents of YBa$_2$Cu$_3$O$_{7}$ step-edge Josephson junctions on SrTiO$_3$(100) substrates have been studied at various step-line angles. 15 identical junctions were made in series on each substrate that has a long straight step-edge line. Step-line angles studied were 0$^{\circ}$, 15$^{\circ}$, 30$^{\circ}$, and 45$^{\circ}$with respect to the crystal major axes of the substrate. Scattering of junction critical currents among the junctions on the same substrate increased with the step-line angle. Current-voltage curves showed standard resistively-shunted-junction (RSJ) characteristics in most of the 0$^{\circ}$junctions. However, the number of junctions showing RSJ behavior decreased with increasing step-line angle. Variations of detailed microstructure of the step-edge among junctions, which are coupled with the d-wave symmetry of YBa$_2$Cu$_3$O$_{7}$, are believed to be the main cause for the nonuniformity in the critical current.ent.

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