Zhi-Min Liao*, Chong Hou, Li-Ping Liu and Da-Peng Yu*
* Corresponding authors: Zhi-Min Liao liaozm@pku.edu.cn - Da-Peng Yu yudp@pku.edu.cn
Nanoscale Research Letters 2010, 5:926-929 doi:10.1007/s11671-010-9585-2