Zhi-Long Chen*, Yun Sun, Peng Huang, Xiao-Xia Yang and Xing-Ping Zhou*
* Corresponding authors: Zhi-Long Chen zlchen1967@yahoo.com - Xing-Ping Zhou xpzhou@dhu.edu.cn
Nanoscale Research Letters 2009, 4:400-408 doi:10.1007/s11671-009-9254-5