1. School of Chemical Engineering, University of Science and Technology Liaoning, Anshan 114051, China
2. Department of Physics, The University of Texas at Arlington, Arlington, Texas 76019-0059, USA
3. State Key Laboratory of Organic–Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, P. R. China
4. Fine Separation Center, University of Science and Technology Liaoning, Anshan 114051, China