基金Supported by the National Natural Science Foundation of China under Grant Nos.6057307470471003(国家自然科学基金)+1 种基金the Natural Science Foundation of Shanxi Province of China under Grant No.2007011040(山西省自然科学基金)the Foundation of Doctoral Program Research of the Ministry of Education of China under Grant No.20050108004(高等学校博士学科点专项科研基金)