[1] Queen Mary Univ London, Sch Engn & Mat Sci, London E1 4NS, England
[2] Queen Mary Univ London, Nanoforce Technol Ltd, London E1 4NS, England
[3] Acad Sci Czech Republ, Inst Phys Mat, Brno 61662, Czech Republic
[4] Politecn Torino, Inst Mat Phys & Engn, Dept Appl Sci & Technol, I-10129 Turin, Italy
[5] Chinese Acad Sci, NIMTE, Ningbo 315201, Zhejiang, Peoples R China
[6] Oak Ridge Natl Lab, Oak Ridge, TN 37831 USA