1. School of Materials Science and Engineering, Lanzhou Jiaotong University, Lanzhou 730070, P. R. China
2. Key Laboratory of Optoelectronic Technology and Intelligent Control of Education Ministry, Lanzhou Jiaotong University, Lanzhou 730070, China
3. Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China
4. Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201204, China