supported by the National Natural Science Foundation of China(No.21172024 to L.-M.Li);the Key Project of Chinese Ministry of Education(No.212151);the NSFC-Joint Foundation of Yunnan Province(No.U0832602 to H.-D. Sun);the Major State Basic Research Development Program of China(Nos. 2009CB522300 and 2009CB940900);the Science and Technology Program of Yunnan Province(Nos. 2008IF010 and 2008CD162);the Major Direction Projection Foundation of CAS Intellectual Innovation Project(No.2010KIBA05 to J.-X.Pu)~~