1. State Key Laboratory of Biochemical Engineering Institute of Process Engineering Chinese Academy of Sciences Beijing 100190 P. R. China
2. Department of Radiology Peking Union Medical College Hospital (Dongdan Campus) Beijing 100730 P. R. China
3. Biological Physics Group Department of Physic and Astronomy The University of Manchester Manchester M13 9PL UK
4. School of Chemical Engineering University of Chinese Academy of Sciences Beijing 100049 P. R. China
5. Center for Mesoscience Institute of Process Engineering Chinese Academy of Sciences Beijing 100049 P. R. China