1. Department of Chemistry University of North Texas 1508 W Mulberry St Denton TX 76201 USA
2. School of Physical Science and Technology Lanzhou University No. 222 South Tianshui Road Lanzhou 730000, Gansu Province P.R. China
3. Department of Chemistry College of Science King Saud University Riyadh, 11451 Saudi Arabia
4. National Center for Nanoscience and Nanotechnology No.11 ZhongGuanCun BeiYiTiao 100190 Beijing P.R. China