1. School of Power and Energy, Northwestern Polytechnical University, 127 West Youyi Road, Xi'an Shaanxi 710072, China
2. Graduate School of Science and Technology, Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan
3. School of Power and Energy,Northwestern Polytechnical University, 127 West Youyi Road, Xi'an Shaanxi 710072, China; Faculty of Engineering,Shizuoka University, 3-5-1 Johoku, Naka-ku, Hamamatsu 432-8561, Japan