1. College of Chemical Engineering, Northwest Minzu University, Key Laboratory of Environment-Friendly Composite Materials of the State Ethnic Affairs Commission, Key Laboratory for Utility of Environment-Friendly Composite Materials and Biomass in University of Gansu Province, Gansu Provincial Biomass Function Composites Engineering Research Center, Lanzhou, Gansu 730030, P. R. China
2. Center of Experiment, Northwest Minzu University, Lanzhou, Gansu 730030, P. R. China