1. School of Electronic and Information Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
2. School of Mechanical and Electrical Engineering, Lanzhou Jiaotong University, Lanzhou 730070, China
3. Engineering Research Center of Integrated Circuit Packaging and Testing, The Ministry of National Education, Tianshui 741000, China
4. School of Electronic Information and Electrical Engineering, Tianshui Normal University, Tianshui 741000, China