1. College of Physics
2. Qingdao University
3. Qingdao 266071
4. China
5. College of Microtechnology & Nanotechnology
6. Electronic Ceramics Center
7. DongEui University
8. Busan 614-714
9. South Korea
10. School of Information Science and Engineering
11. Shandong University
12. Qingdao 266237