基金This work was supported by the National Natural Science Foundation of China (10471151)National 863 Project(2003AA148040)the Educational Science Foundation of Chongqing,Chongqing of China(041302).
基金Supported by the National Natural Science Foundation of China(11071053)the Natural Science Foundation of Hebei Province(A2010001482)the Project of Science and Research of Hebei Education Department(the second round in 2010)