1. School of Energy and Power Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, Jiangsu, PR China.
2. School of Mechanical Engineering, Nanjing University of Science and Technology, Nanjing 210094, Jiangsu, China
3. George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, GA 30332 USA, and also with the Key Laboratory of Road Construction Technology and Equipment of MOE, Chang'an University, Xi'an 710064, Shanxi, China.