1. Key Laboratory of Coal Science and Technology of Ministry of, Education and Shanxi Province; Taiyuan University of Technology; Taiyuan 030024 Shanxi P.R. China
2. Department of Chemical Engineering and Department of, Petroleum Engineering; University of Wyoming; Laramie WY 82071 USA
3. College of Chemistry and Chemical Engineering; Taiyuan University of Technology; Taiyuan 030024 Shanxi P.R. China
4. State Key Laboratory of Fine Chemicals; School of Chemical Engineering; Dalian University of Technology; Dalian 116024 Liaoning P.R. China
5. Department of Civil and Environmental Engineering; Stanford University; Stanford CA 94305 USA
6. School of Civil and Environmental Engineering; Georgia Institute of Technology; Atlanta GA 30332 USA