Guotao Duan, Fuhai Su*, Wen Xu*, Cunlin Zhang and Weiping Cai
* Corresponding authors: Fuhai Su fhsu@issp.ac.cn - Wen Xu wenxu_issp@yahoo.cn
Nanoscale Research Letters 2012, 7:657 doi:10.1186/1556-276X-7-657