基金supported by a grant from National Natural Science Foundation of China(10901003)NSF of Anhui Educational Bureau(KJ2009A128)Anhui Normal University Young Scientific Foundation(2008xqn44)
基金Supported by the National Natural Science Foundation of China(11201004 and 11271020)the Key Project of Chinese Ministry of Education(211077)the Anhui Provincial Natural Science Foundation(10040606Q30 and 1208085MA11)