Jun Zhang, Su-Qing Zhao*, Kun Zhang, Jian-Qing Zhou and Yan-Fei Cai*
* Corresponding authors: Su-Qing Zhao sqzhao@gdut.edu.cn - Yan-Fei Cai yanfeicai@scau.edu.cn
Nanoscale Research Letters 2012, 7:405 doi:10.1186/1556-276X-7-405