3 research outputs found

    Single- and multi-walled carbon nanotubes viewed as elastic tubes with Young's moduli dependent on layer number

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    The complete energy expression of a deformed single-walled carbon nanotube (SWNT) is derived in the continuum limit from the local density approximation model proposed by Lenosky {\it et al.} \lbrack Nature (London) {\bf 355}, 333 (1992)\rbrack and shows to be content with the classic shell theory by which the Young's modulus, the Poisson ratio and the effective wall thickness of SWNTs are obtained as Y=4.70Y=4.70TPa, ν=0.34\nu=0.34, h=0.75A˚h=0.75{\rm \AA}, respectively. The elasticity of a multi-walled carbon nanotube (MWNT) is investigated as the combination of the above SWNTs of layer distance d=3.4A˚d=3.4 {\rm \AA} and the Young's modulus of the MWNT is found to be an apparent function of the number of layers, NN, varying from 4.70TPa to 1.04TPa for N=1 to ∞\infty.Comment: 4 pages, 1 figur

    La multiplication végétative chez les végétaux vasculaires

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    NUTRITION, GROWTH AND MORPHOGENESIS OF PLANT EMBRYOS

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