1. Department of Materials Science and Engineering
2. College of Engineering
3. Key Laboratory of Polymer Chemistry and Physics of Ministry of Education
4. Peking University
5. Beijing 100871
6. State Key Laboratory for Mechanical Behavior of Materials
7. Xi'an Jiaotong University
8. Xi'an 710049
9. P. R. China
10. Advanced Light Source
11. Laurence Berkeley National Laboratory
12. Berkeley
13. USA