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, Northwest New Village No. 1., P. R. China
2. College of Petrochemical Technology, Lanzhou University of Technology, Langongping road No. 287, P. R. China