Enseigner Maeterlinck, La Princesse Maleine

Adapté aux exigences de l’enseignement d’aujourd’hui, le « parcours didactique » que nous présentons ici vise à développer chez des étudiants de cinquième ou de sixièmeannée de l’enseignement général différentes « compétences terminales » relatives à la connaissance et à la compréhension de la littérature. En l’occurrence, à travers l’étude de La Princesse Maleine de Maurice Maeterlinck, nous voudrions favoriser l’acquisition de compétences génériques par l’étude d’une pièce de théâtre, de co..

Evidence for transition from polaron to bipolaron conduction in LixCr0.11V2O5.16: a dynamic study from 10 to 10^10 Hz

LGEP 2011 ID = 840International audienceThis paper presents a study on the electrical transport properties of lithiated Cr0.11V2O5.16, which can be used as a rechargeable cathodic material in lithium batteries. Dielectric and conductivity spectra of Li,Cr0.11V2O5.16 powders (x=0, 0.05, 0.40 and 1.20) were recorded in a broad frequency range of 10-1010 Hz at temperature varying between 300 and 400 K. Complex resistivity diagrams have enabled to obtain thermal behaviors of bulk dc-conductivity. Dielectric relaxations were found, attributed to small polarons and (intersite) bipolarons hopping. The transport properties are shown to be consistent with small polaron and bipolaron conduction models. The change from polaronic to bipolaronic conduction has been evidenced with the increase of the lithium content x from 0.40 to 1.20. This work opens up new prospects for a more fundamental understanding of the electronic transport in relation with the electrochemical properties of Cr0.11V2O5.16

Dynamic homogenization of split-ring metamaterials by Floquet-Bloch decomposition

International audienceWe apply a novel dynamic homogenization technique to determine the frequency-dependent effective permeability of split-rings arrays. The Floquet-Bloch decomposition of Maxwell equations in this metamaterial is applied when the wavelength is much bigger than the material's period. We replace the inclusion with a closed ring, and numerically simulate the model by nodal finite elements and a reasonable number of tetrahedral mesh elements. Our results show a good agreement with an analytical permeability law for 2D structures. This work also proposes an accurate method to model the magnetic field in the unit cell

Application of microwave reflectometry to disordered petroleum multiphase flow study

International audienceMicrowave reflectometry is applied to multiphase flow metering in the context of oil extraction. Our sensor consists of two open-ended coaxial probes operating at complementary frequencies (at 600 MHz and around 36 GHz) and was designed to resist harsh field conditions. This paper presents and comments on results obtained in realistic dynamic conditions, on a triphasic flow loop (water-oil-gas). The main conclusions are the following: Bruggeman-Hanai's mixing rule applies to natural emulsions and can be used to determine the composition of the water-oil liquid phase; results obtained for annular flows are very sensitive to small perturbations such as bubbles or waves at the liquid-gas interface; in the case of triphasic slug flows, the composition of the liquid phase can be estimated by proper filtering of the data