国家自然科学基金项目51277067,71271082;中央高校基本科研业务费专项资金资助2015XS37;国家软科学研究计划项目2012GXS4B064.Project Supported by National Natural Science Foundation of China51277067,71271082;The Fundamental Research Funds for the Central Universities2015XS37;National Soft Science Research Project2012GXS4B064