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    Subject Crystallography on Curved Surfaces: Virus Buckling and Grain Boundary Scars (Crystallography on Curved Surfaces: Virus Buckling and Grain Boundary Scars)
    TYPE 특별 강연
    DATE/TIME 2006-11-27 ~ 2006-11-27
    PLACE APCTP Seminar Room (APCTP Seminar Room)
    SPEAKER Prof. David R. Nelson (Prof. David R. Nelson)
    AFFILIATION Harvard University (Harvard University)
    * 연  사 : Prof. David R. Nelson (Harvard Univ.)
    * 일  시 : 2006년 11월 27일(월) 오후 3시 
    * 장  소 : APCTP 세미나실(무은재기념관 5층 512호) 
    * 주  최 : 아시아태평양 이론물리센터(APCTP), 포스텍 이론물리연구소(PCTP) 

    * Speaker : Prof. David R. Nelson (Harvard Univ.)
    * Date : 2006년 11월 27일(월) 오후 3시 
    * Place : APCTP 세미나실(무은재기념관 5층 512호) 
    * Hosted by APCTP, POSTECH 
    Ordered states on spheres require a minimum number of topological defects. The difficulty of constructing ordered states was recognized by J. J. Thomson, who discovered the electron and then attempted regular tilings of the sphere in an ill-fated attempt to explain the periodic table.  One set of solutions to this "Thomson problem" requires that regular triangular lattices be interrupted by an array of at least 12 five-fold disclination defects, typically sitting at the vertices of an icosahedron.  For R>>a, where R is the sphere radius and a is the particle spacing, the energy associated with these defects is very large. This energy can be lowered, however, either by buckling, as appears to be the case for large viruses, or by introducing unusual finite length grain boundary scars.  The latter have been observed recently for colloidal particles adsorbed onto water droplets in oil.  Related problems involving crystalline and liquid crystal patterns on other curved surfaces will be discussed as well.

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