1. National & Local Joint Engineering Research Center for Applied Technology of Hybrid Nanomaterials; Henan University; Kaifeng 475004 P.R. China
2. Department of Chemistry; University College London; 20 Gordon Street London WC1H 0AJ UK
3. School of Computer Science; University of Birmingham; Birmingham B15 2TT UK
4. Nanoengineered Systems Laboratory; UCL Mechanical Engineering; University College London; London WC1E 7JE UK