1. School of Material Science and Engineering, Lanzhou University of Technology
2. Lanzhou 730050
3. P. R. China
4. Lanzhou Chemical Research Center of PetroChina Co Ltd
5. Lanzhou 730060
6. College of Life Science and Engineering, Lanzhou University of Technology
7. College of Petrochemical Technology, Lanzhou University of Technology
8. State Key Laboratory of Advanced Processing and Recycling of Non-ferrous Metals, Lanzhou University of Technology