[1] Rensselaer Polytech Inst, Dept Phys Appl Phys & Astron, Troy, NY 12180 USA
[2] Chinese Acad Sci, Inst High Energy Phys, CAS Key Lab Biomed Effects Nanomat & Nanosafety, Beijing 100049, Peoples R China
[3] Natl Ctr Nanosci & Technol, Beijing 100191, Peoples R China
[4] Natl Inst Nat Sci, Inst Mol Sci, Dept Theoret & Computat Mol Sci, Okazaki, Aichi 4448585, Japan