▎ 摘　　要

The roles of defects including monatomic vacancies and Stone-Wales dislocations in the mechanical and thermal properties of graphene are investigated here through molecular dynamics ( MD) simulations. The results show that Young's modulus of a defected graphene sheet has a gentle dependence with the concentration of defects, while the thermal conductivity is much more sensitive. Analysis based on the effective medium theory (EMT) indicates that this sensitivity originates from the scattering of phonons by defects and delocalized interaction between them, which leads to a transition from propagating to diffusive mode as the concentration increases. (C) 2011 American Institute of Physics. [doi:10.1063/1.3615290]