1. Key Laboratory of Coal Methane
and Fire Control, Ministry of
Education, China University of Mining and Technology, Xuzhou, Jiangsu 221116, China
2. State Key
Laboratory
of Coal Resources and Safe Mining, Xuzhou, Jiangsu 221116, China
3. Department of Energy and Mineral
Engineering, G3 Center
and Energy Institute, Pennsylvania State University, University Park, Pennsylvania 16802, United States