1. Key Laboratory of Materials Modification by Laser, Ion, and Electron Beams (Ministry of Education), School of Physics, Dalian University of Technology 1 , Dalian 116024, China
2. School of Electrical Engineering, Dalian University of Technology 2 , Dalian 116024, China
3. College of Sciences, Liaoning Petrochemical University 3 , Fushun 113001, China