National Natural Science Foundation of China No.31371979;Doctoral Foundation of Ministry of Education of China No.20120031110019;Tianjin Natural Science Foundation No.12JCYBJC198000国家自然科学基金项目No.31371979;教育部博士点基金项目No.20120031110019;天津市自然科学基金项目No.12JCYBJC198000