[1] Univ Paris 06, Phys & Mecan Milieux Heterogenes Lab, Ecole Super Phys & Chim Ind Ville Paris, CNRS,UMR 7636, F-75231 Paris 5, France
[2] Univ Paris 07, Phys & Mecan Milieux Heterogenes Lab, Ecole Super Phys & Chim Ind Ville Paris, CNRS,UMR 7636, F-75231 Paris 5, France
[3] CNRS, LIMSI, UPR 3251, F-91403 Orsay, France