1. Department of Materials Physics and Chemistry
2. School of Materials Science and Engineering
3. Northeastern University
4. Shenyang
5. P. R. China
6. Department of Physics and Biophysics
7. School of Fundamental Sciences
8. China Medical University
9. Institute of Nano Science and Physical Engineering
10. Kim Chaek University of Technology
11. Pyongyang
12. Democratic People's Republic of Korea