国家自然科学基金71373204;陕西省教育厅哲学社会科学重点研究基地科学研究计划资助项目13JZ036;陕西省普通高校重点学科专项资金建设资助项目107-5X1302Supported by the National Natural Science Foundation of China71373204;the Shaanxi Provincial Education Department of Philosophy and Social Science Research Base of Scientific Research Projects13JZ036;the Special Foundation for Construction of Key Discipline in Shaanxi University107-5X1302