基金Supported by the Science Research Foundation of HunanProvincial Education Depart ment ( No 02C098)theScience Research Foundation of Hunan University of Artsand Science (No JJZD 0502)
基金Supported by the Youth Talent Foundation of Anhui Province(2010SQRL146)the Anhui Provincial NaturalScience Research Project of University(KJ2010B106)