1. Center for Nanochemistry Beijing Science and Engineering Center for Nanocarbons Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular Engineering Peking University Beijing 100871 P. R. China
2. Department of Engineering Mechanics School of Civil Engineering Wuhan University Wuhan Hubei 430072 P. R. China
3. School of Material Science and Engineering Peking University Beijing 100871 P. R. China