1. Materials Research Center
2. Institute of Modern Physics
3. Chinese Academy of Sciences
4. Lanzhou 730000
5. P. R. China
6. Department of Applied Physics
7. The Hong Kong Polytechnic University
8. Hong Kong
9. China
10. Materials Research Department
11. GSI Helmholtz Centre for Heavy Ion Research
12. 64291 Darmstadt
13. Germany
14. Materials Science
15. Shenzhen Research Institute