主题：On the Isotropic-Nematic Phase Transition for the Liquid Crystal
In this talk, we study the isotropic-nematic phase transition for the nematic liquid crystal based on the Landau-de Gennes Q-tensor theory. We justify the limit from the Landau-de Gennes flow to a sharp interface model: in the isotropic region, Q=0; in the nematic region, the Q-tensor is constrained on the manifolds N, and the evolution of alignment vector field obeys the harmonic map heat flow; while the interface separating the isotropic and nematic regions evolves by the mean curvature flow. This problem can be viewed as a concrete but representative case of the Rubinstein-Sternberg-Keller problem. This is a joint work with Professor Wei Wang in ZJU, Professor Pingwen Zhang and Professor Zhifei Zhang in PKU.