1. Engineering Research Center in Biomaterials, Sichuan University, Chengdu, Sichuan 610065, P. R. China
2. Analytical & Testing Center, Sichuan University, Chengdu, Sichuan 610065, P. R. China
3. Metrology Research Centre, National Research Council Canada, Ottawa, Ontario K1A 0R6, Canada
4. Institute of Atomic and Molecular Physics, Sichuan University, Chengdu, Sichuan 610065, P. R. China
5. Laboratory of Ethnopharmacology, West China School of Medicine, West China Hospital, Sichuan University, Chengdu, Sichuan 610065, P. R. China