1. State Key Laboratory of Chemical Resource Engineering, Beijing University of Chemical Technology, Beijing 100029, P. R. China
2. Beijing Laboratory of Biomedical Materials, Key Laboratory of Biomedical Materials of Nature Macromolecules, Ministry of Education, Beijing University of Chemical Technology, Beijing 100029, P. R. China
3. School of Chemistry and Chemical Engineering, Ningxia University, Yinchuan 750021, P. R. China