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♠ POSTECH 개교20주년 기념사업 석학초청 강연 안내

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2006.10.11 / 543

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POSTECH 개교20주년 기념사업의 일환으로 석학초청 강연을 아래와 같이 실시합니다.

  
  연사 : Prof. David R. Nelson
           (Lyman Laboratory of Physics , Harvard University)

  
  [강연-01( technical lecture (at the level of a physics colloquium))]

  일시 : 2006년 11월 27일(월) , 오후 3시 ~ 4시
  장소 : 무은재기념관 5층 512호 (APCTP 세미나실)
  강연제목 : Crystallography on Curved Surfaces: Virus Buckling and
                 Grain Boundary Scars
  강연내용 : 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 he sphere in an ill-fated attempt to explain the periodic table.  One set
of solutions to thisThomson 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.



    [강연-02(public lecture)]

  일시 : 2006년 11월 28일(화) , 오전11시 ~ 12시30분
  장소 : 정보통신연구소 중강당
  강연제목 : Polymers, Biophysics and Crumpling
  강연내용 : The past decade has witnessed a revolution in polymer science and biophysics, as scientists use exquisitely sensitive tools such as laser tweezers, novel linking agents and magnetic micro-beads to probe polymeric ingredients of thecentral dogma of biology, such as DNA and RNA, one molecule at a time.  We discuss the role played by entropic elasticity, and describe experiments with force-induced unzipping of DNA.  
Flexible polymerized ortethered membranes, which are natural generalizations of these linear polymer chains, are treated next.  We again turn to biology, and discuss the spectrin skeleton of red blood cells.  Theory predicts a remarkable flat phase, with anomalous roughness and singular elastic constants, caused by a delicate interplay between thermal fluctuations and the Gaussian curvature.  Related issues associated with thefractal dimension of a crumpled piece of paper will be discussed as well.

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