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Transformée en ondelettes : applications aux propriétés diélectriques et mécaniques de nanostructures carbonées

Abstract : In order to model the response of a gas sensor containing carbon nanotubes to various polarizable gases (A. M. Rao, Clemson University), we use a renormalized dipolar interaction model with anisotropic polarizabilities localized on the carbon atoms. This model, calibrated to find the experimental polarizabilities of fullerenes, gives plausible phenomenologic laws for the polarizabilities of carbon nanotubes. Moreover, it reproduces very well the results of Rao et al., which points towards the development of a sensor both very sensitive and selective. Then, we model the deflection at equilibrium of single-walled carbon nanotubes fixed at one end and subjected to a static and uniform electric field. A cylindrical beam model with localised constraint fits well the curves obtained for weak deflections, with however an effective Young's modulus lower than the experimental values, contrary to a good agreement in the case of the purely mechanical deflection of the tubes. This shows the interest of an atomistic simulation for the study of the Nano ElectroMechanical Systems. Finally, we develop an algorithm to solve the matrix system describing the dipolar interactions of a nanotube by wavelet transform, and an algorithm specific for sparse matrices. Thus we show that for a maximal decomposition level, results are much better than for the standard algorithm in term of computing time or RAM size used. Indeed, this opens new possibilities to deal with bigger systems closer to experiment.
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https://tel.archives-ouvertes.fr/tel-00009019
Contributor : Rachel Langlet <>
Submitted on : Thursday, April 14, 2005 - 2:16:18 PM
Last modification on : Tuesday, October 27, 2020 - 2:34:06 PM
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Rachel Langlet. Transformée en ondelettes : applications aux propriétés diélectriques et mécaniques de nanostructures carbonées. Physique [physics]. Université de Franche-Comté, 2004. Français. ⟨tel-00009019⟩

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