Mechanical coupled vibrations in an individual double-walled carbon nanotube Mourad Boutahir, Abdelhai Rahmani, Hassan Chadli and Abdelali Rahmani Eur. Phys. J. Appl. Phys., 74 2 (2016) 24605 Published online: 03 May 2016 DOI: 10.1051/epjap/2015150329