1. School of Mathematics and Statistics, Xi'an Jiaotong University, Xi'an Shaanxi, People's Republic of China
2. School of Mechatronic Engineering and Shaanxi Key Laboratory of Non-Traditional Machining, Xi'an Technological University, Xi'an Shaanxi, People's Republic of China
3. School of Science, Chang'an University, Xi'an Shaanxi, People's Republic of China