Non destructive observation by X-ray diffraction on a berlinite crystal

For the characterisation of a crystal, several non destructive observations can be made by X-Ray diffraction. The crystal may be studied either as a block as grown from the autoclave or as a cut or a finished resonator. Once the crystal is placed on a special piezogoniometer its orientation may be measured and its orientation matrix calculated. Then, the most useful lattices planes are chosen, some of them allow the determination of the lattice parameters, others the detection of defects as twins or a mosaic structure. Illustrations are made on a berlinite crystal showing some macroscopic defects

Restauration hydraulique et écologique du Rhône : problématique, méthodologie et indicateurs d'évolution post-restauration

International audiencePrésentation de la restauration physique du fleuve et de ses effets

Modèles de sélection des micro-habitats aquatiques: nouvelles méthodes prenant en compte la surdispersion des abondances

International audienceA novel approach of fish and macroinvertebrates micro-habitat selection models: how to deal with spatial and temporal variations of overdispersed abundance data