1. a School of Chemistry and Chemical Engineering, Hunan University of Science and Technology, Key Laboratory of Theoretical Chemistry and Molecular Simulation of Ministry of Education, Hunan Province College Key Laboratory of QSAR/QSPR , P. R. China
2. c State Key Laboratory of Powder Metallurgy, Central South University , Changsha , P. R. China
3. b Hunan Province Key Laboratory of Coal Resources Clean-utilization and Mine Environment Protection , Xiangtan , P. R. China