国家自然科学基金资助项目81641150;陕西省科技厅社会发展项目2015SF242;陕西省教育厅专项科研计划项目No.16JK1659.Supported by the National Natural Science Foundation of China81641150;the Tackling Project of Scientific and Technological Social Development from Science and Technology Department of Shaanxi Province2015SF242;the Special Research Project of Education Department of Shaanxi Province16JK1659