An EFTEM/HRTEM high resolution study of the near surface of labradorite feldspar altered at acid pH: evidence for interfacial dissolution-reprecitation.

International audienc

Hybrid material for electromagnetic absorption

L'invention concerne un matériau hybride (10) destiné à absorber un rayonnement électromagnétique (60) et un procédé de fabrication d'un tel matériau. Le matériau hybride (10) comprend au moins un panneau formant grille (20) ayant une épaisseur t 1 et comportant des trous (25) traversant ladite épaisseur t 1 , au moins un matériau composite polymère (30) ayant une épaisseur t 2 remplissant au moins partiellement les trous (25) dudit panneau formant grille (20), ledit matériau composite polymère (30) comprenant une matrice polymère (40) et des particules conductrices (50) dispersées au sein de ladite matrice polymère (40), et est caractérisé en ce que la surface interne des trous (25) dudit panneau formant grille (20) est métallique

Multifunctional Hybrids for Electromagnetic Absorption

Electromagnetic (EM) interferences are ubiquitous in modern technologies and impact on the reliability of electronic devices and on living cells. Shielding by EM absorption, which is preferable over reflection in certain instances, requires combining a low dielectric constant with high electrical conductivity, which are antagonist properties in the world of materials. A novel class of hybrid materials for EM absorption in the gigahertz range has been developed based on a hierarchical architecture involving a metallic honeycomb filled with a carbon nanotube-reinforced polymer foam. The waveguide characteristics of the honeycomb combined with the performance of the foam lead to unexpectedly large EM power absorption over a wide frequency range, superior to any known material. The peak absorption frequency can be tuned by varying the shape of the honeycomb unit cell. A closed form model of the EM reflection and absorption provides a tool for the optimization of the hybrid. This designed material sets the stage for a new class of sandwich panels combining high EM absorption with mass efficiency, stiffness and thermal management