四川省学术和技术带头人培养基金25727502;西南民族大学研究生学位点建设项目批准号:2015XWD-S0805资助的课题.* Project supported by the Sichuan Provincial Foundation for Leaders of Disciplines in Science and Technique, ChinaGrant 25727502;the Foundation for Graduate Degree of Southwest University for Nationalities, ChinaGrant 2015XWD-S0805