École normale supérieure de Cachan

About: École normale supérieure de Cachan is a education organization based out in Cachan, Île-de-France, France. It is known for research contribution in the topics: Decidability & Finite element method. The organization has 2717 authors who have published 5585 publications receiving 175925 citations.

Competition for attention in the Information (overload) Age

Abstract: Limited consumer attention limits product market competition: prices are stochastically lower the more attention is paid. Ads compete to be the lowest price in a sector but compete for attention with ads from other sectors: equilibrium ad shares follow a CES form. When a sector gets more proÞtable, its advertising expands: others lose ad market share. The "information hump" shows highest ad levels for intermediate attention levels. The Information Age takes off when the number of viable sectors grows, but total ad volume reaches an upper limit. Overall, advertising is excessive, though the allocation across sectors is optimal.

Nanocavitation in Carbon Black Filled Styrene–Butadiene Rubber under Tension Detected by Real Time Small Angle X-ray Scattering

Abstract: Nanocavitation was detected for the first time in carbon black filled styrene–butadiene rubber (CB-SBR) under uniaxial loading by real time small-angle X-ray scattering (SAXS) using synchrotron X-ray radiation. A three phase model was developed to calculate the void volume fraction from the scattering invariant Q determined from the observed SAXS patterns. The normalized scattering invariant Q/Q0, where Q0 is the invariant before deformation, greatly increased above a critical extension ratio λonset which we attribute to the formation of nanovoids. Analysis of the 2D scattering patterns show that voids formed are 20–40 nm in size and elongated along the tensile direction. Cavities formed beyond λonset are smaller as λ increases. Results from the scattering experiments are strongly supported by macroscopic volume change measurements on the samples under similar uniaxial strain. A nearly constant nanocavitation stress σonset (25 MPa) was observed when the filler volume fraction ϕCB was larger than 14%. This...

Particularities of surface plasmon–exciton strong coupling with large Rabi splitting

Abstract: This paper presents some of the particularities of the strong coupling regime occurring between surface plasmon (SP) modes and excitons. Two different active materials were deposited on a silver film: a cyanine dye J-aggregate, and a two-dimensional layered perovskite-type semiconductor. The dispersion relations, which are deduced from angular resolved reflectometry spectra, present an anticrossing characteristic of the strong coupling regime. The wavevector is a good parameter to determine the Rabi splitting. Due to the large interaction energies (several hundreds of milli-electron-volts), the calculations at constant angle can induce an overestimation of the Rabi splitting of more than a factor of two. Another property of polaritons based on SP is their nonradiative character. In order to observe the polaritonic emission, it is thus necessary to use particular extraction setups, such as gratings or prisms. Otherwise only the incoherent emission can be detected, very similar to the bare exciton emission.

A Study of Large Plastic Deformations in Dual Phase Steel Using Digital Image Correlation and FE Analysis

Abstract: Large plastic deformation in sheets made of dual phase steel DP800 is studied experimentally and numerically. Shear testing is applied to obtain large plastic strains in sheet metals without strain ...