Supported by the Natural Science Foundation of China(11071001);the Program of Natural Science Research in Anhui Colleges and Universities(KJ2010ZD02,KJ2011A020);the Scientific Research Starting Fund for Dr of Anhui University;the Research Fund for Doctoral Program of Higher Education of China(20093401110001);the 211 Project of Anhui University(KJT-D002B, KJQN1001)