The authors would like to thank the editors and the anonymous reviewers for their constructive comments and suggestions. In addition, this research was financially supported by the National Natural Science Foundation of China (Nos. 71501080 , 71501054 , 71671060 , 71420107026 and 71331002 ), the Major Project of the National Social Science Foundation of China (No. 13&ZD183 ), and the specific funding for education science research by self-determined research funds of CCNU from the colleges’ basic research and operation of MOE (Nos. CCNU16JYKX35 , CCNU16JYKX38 ).