1. School of Physics
and Electronics, State Key Laboratory of Advanced Design and Manufacturing
for Vehicle Body, Hunan University, Hunan 410082, P. R. China
2. State Key Laboratory of Advanced Design
and Manufacturing for Vehicle Body, National Engineering Research
Center for High Efficiency Grinding, College of Mechanical and Vehicle
Engineering, Hunan University, Hunan 410082, P. R. China
3. College of Optoelectronic Science and Engineering, National University of Defense Technology, Changsha 410073, P. R. China
4. College of Physics and Electronic Engineering, Northwest Normal University, Lanzhou 730070, P. R. China