1. Associate Professor, Dept. of Thermal Science and Energy Engineering, Univ. of Science and Technology of China, Hefei, Anhui 230026, P.R. China (corresponding author).
2. Professor, Dept. of Thermal Science and Energy Engineering, Univ. of Science and Technology of China, Hefei, Anhui 230026, P.R. China.
3. PhD Student, Dept. of Thermal Science and Energy Engineering, Univ. of Science and Technology of China, Hefei, Anhui 230026, P.R. China.
4. PhD Student, Dept. of Operations Research and Financial Engineering, Princeton Univ., Princeton, NJ 08540.