1. Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
2. Materials Science Division, Argonne National Laboratory, Lemont, Illinois 60439, USA
3. University of Chinese Academy of Sciences, Beijing 100049, China
4. Institute of Physics, Chinese Academy of Sciences, Beijing 100190, China
5. X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Lemont, Illinois 60439, USA