国家自然科学基金61370083,61073043,61073041,61370086;国家教育部博士点基金20112304110011,20122304110012资助@@@@Supported by National Natural Science Foundation of China61370083,61073043,61073041,61370086;National Re-search Foundation for the Doctoral Program of Higher Educa-tion of China20112304110011,20122304110012