1. Research Assistant, China-Canada Energy and Environmental Research Center, North China Electric Power Univ., Beijing 102206, China.
2. Professor, MOE Key Laboratory of Regional Energy and Environmental Systems Optimization, Resources and Environmental Research Academy, North China Electric Power Univ., Beijing 102206, China.
3. Professor, Graduate Studies Advisor, Dept. of Civil and Resource Engineering, Dalhousie Univ., 1360 Barrington St., Bldg.D, Rm. D215, P.O. Box 15000, Halifax, NS, Canada B3H 4R2 (corresponding author).
4. Research Assistant, School of Mechanical Engineering, Univ. of Science and Technology Beijing, Beijing 100083, China.