基金supported by the National Natural Science Foundation of China(No.51077018)the Heilongjiang Provincial Natural Science Fundation(No.F201219)the Program for Young Teachers Scientific Research in Qiqihar University(No.2012k-Z12),China
基金Supported by the National Natural Science Foundation of China (Grant No .50575191)the Scienceand Technology Programof Xiamen (Grant No .3502Z20063006)