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收集所有交通大學研究人員與學生個人或團體所發表之各項學術著作，涵蓋期刊論文、教師專書、學位論文等項。;;Collections of Publications of NCTU Researchers and Students Like Journal Papers and Thesis.

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🏛️國立陽明交通大學機構典藏

Subject: search.filters.subject.NEMATIC LIQUID CRYSTAL

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Now showing 1 - 3 of 3
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    DISCONTINUOUS RADIAL TO AXIAL TRANSFORMATION OF DIRECTOR CONFIGURATION IN A CYLINDRICAL NEMATIC CAVITY
    (1991-11-15)
    LIANG, BJ
    ;
    CHEN, SH
    ;
    交大名義發表
    ;
    電子物理學系
    ;
    National Chiao Tung University
    The optical patterns of a nematic liquid crystal confined to a closed cylindrical cavity are observed through crossed polarizers. This optical pattern exhibits an annular phenomenon when the radius of the cylinder is varied. The minor dependence of the width of the bright annulus on the radius of the cavity is presented. The formation of the disclination ring is numerically studied and found to be the physical mechanism of the annular phenomenon. The characteristic length defined as the distance from the ring defect to the laterally cylindrical boundary is nearly invariant and is characterized to be the width of the bright annulus.
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    Item type:Item,
    STABILITY OF AN UMBILICAL DIRECTOR FIELD OF NEMATIC LIQUID-CRYSTAL IN A CLOSED CONICAL CAVITY
    (1994-05-01)
    WEI, JG
    ;
    CHEN, SH
    ;
    交大名義發表
    ;
    光電工程學系
    ;
    National Chiao Tung University
    This letter studies the stability of a single umbilical director field of nematic liquid crystal (NLC) in a closed cavity with external electric field. To form the single umbilic structure, we filled NLC with negative dielectric anisotropy in a closed conical cavity and made molecules align perpendicular to the cavity wall. Electric field was applied along the symmetry axis of the cavity. Using the continuum theory, we show that an umbilical director field will transform to a director field of a hyperbolic singular point with disclination ring instead of a Poincare structure at a critical voltage.
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    Item type:Item,
    ELECTRIC-FIELD-INDUCED DIRECTOR-FIELD TRANSITION OF NEMATIC LIQUID-CRYSTAL IN A CLOSED CONICAL CAVITY
    (1994-11-01)
    WEI, JG
    ;
    CHEN, SH
    ;
    交大名義發表
    ;
    光電工程學系
    ;
    National Chiao Tung University
    Continuum theory and numerical method are utilized in this study to report the dependence of director-field transition induced by electric field on the elastic constants of nematic liquid crystal (NLC) with negative dielectric anisotropy in a closed conical cavity with perpendicular boundary conditions of NLC. Normal umbilic structure (NU), twisted umbilic structure (TU), normal hyperbolic point structure with a disclination ring (NH), twisted hyperbolic point structure with a disclination ring (TH), and normal Poincare structure (NP) are found to be stable structures in electric-field-induced transitions. Moreover, five typical sequences of transition, T-NU-->TU-->TH, T-NU-->TU-->NH-->TH, T-NU-->TU-->NH, T-NU-->NH, and T-NU-->NP-->NH are found in the range of applied voltage less than 10 V. The transition sequences and the transition voltages are strongly dependent on the ratios of elastic constants K-11/K-33 and K-22/K-33.