1. School of Mechanical Engineering
2. Dongguan University of Technology
3. Dongguan 523808
4. P. R. China
5. School of Materials Science and Engineering
6. Shanghai Institute of Microsystem and Information Technology
7. Chinese Academy of Sciences
8. Shanghai 200050
9. Department of Physics
10. South University of Science and Technology of China
11. Shenzhen 518055
12. Nanchang University
13. Nanchang 330031
14. The University of New South Wales
15. Sydney
16. Australia
17. Department of Applied Physics and Materials Research Center
18. The Hong Kong Polytechnic University
19. Hung Hom
20. Kowloon