Grenoble Institute of Technology

About: Grenoble Institute of Technology is a education organization based out in Grenoble, France. It is known for research contribution in the topics: Hyperspectral imaging & Geology. The organization has 3427 authors who have published 5345 publications receiving 137158 citations. The organization is also known as: Grenoble INP.

High-pressure effect on PbTiO3: an investigation by Raman and x-ray scattering up to 63 GPa.

Abstract: We report a room-temperature high-pressure x-ray and Raman scattering investigation of lead titanate (PbTiO3) up to 63 GPa. Three continuous phase transitions at 13, 20, and 45 GPa between tetragonal-like phases occur. As a result, no evidence is found for a pressure-induced morphotropic phase boundary. Our study provides experimental evidence that PbTiO3 presents a complex sequence of phases accommodating pressure through mechanisms involving oxygen octahedra tilting and reentrance of ferroelectricity.

On the validity of simple precipitate size measurements by small-angle scattering in metallic systems

Abstract: This paper assesses how simple small-angle scattering particle size evaluation models, such as Porod or Guinier radii, which have a normally limited validity range, may see this range extended to larger q values. This is shown to be particularly true for metallic systems, where the dispersion in particle size is always large. Because of the size dispersion, the relationship between the average particle size and the Guinier radius is shown to change. For systems with relatively large size dispersion, the paper shows that the Porod and Guinier radii, and simple extensions thereof, give valuable information on particle size and particle size distribution. This is demonstrated to be valid for particles with moderate aspect ratios. These simple evaluations are quick and very well adapted to large data sets, such as those originating from time-resolved or scanning small-angle experiments.

How does adhesion induce the formation of telephone cord buckles

Abstract: Compressively stressed thin films with low adhesion frequently buckle and delaminate simultaneously into telephone cords. Although these buckles have been studied for decades, no complete understanding of their propagation has so far been presented. In this study, we have coupled a nonlinear plate deformation with a cohesive zone model to simulate the kinematics of a propagating telephone cord buckle in very close agreement with experimental observations. Proper inclusion of the dependence of an adhesion upon the mode mixity proved to be central to the success of the approach. The clarification of the mechanism promises better understanding of buckle morphologies.