1. College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070 (P.R. China)
2. State Key Laboratory of Advanced Technology for Materials Synthesis and Processing, Wuhan University of Technology, Wuhan 430070 (P.R. China)
3. Department of Physics, Faculty of Science, King Abdulaziz University, Jeddah 21589 (Saudi Arabia) http://www.researcherid.com/rid/G‐4317‐2010