Qu’est-ce donc que ce mot barbare? Sous ce terme scientifique se cache un phénomène assez connu, globalement celui des sables mouvants. On dit d’un matériau qu’il est thixotrope si, en réponse à une contrainte (agitation mécanique, ondes sismiques, cisaillment) sa … Lire la suite
NEW PUBLICATION IN SCIENCE The bulk of the comet 81P/Wild 2 (hereafter Wild 2) samples returned to Earth by the Stardust spacecraft appear to be weakly constructed mixtures of nanometer-scale grains, with occasional much larger (over 1 micrometer) ferromagnesian silicates, … Lire la suite
NEW PUBLICATION IN SCIENCE The Stardust spacecraft collected thousands of particles from comet 81P/Wild 2 and returned them to Earth for laboratory study. The preliminary examination of these samples shows that the nonvolatile portion of the comet is an unequilibrated … Lire la suite
NEW PUBLICATION IN AMERICAN MINERALOGIST The tetragonal hollandite structure (KAlSi3O8 hollandite) has been studied up to 32 GPa at room temperature using high-pressure in-situ X-ray diffraction techniques. A phase transformation from tetragonal I4/m phase to a new phase was found … Lire la suite
NEW PUBLICATION In situ X-ray diffraction measurements have been made on KAlSi3O8 hollandite using diamond anvil cell and multianvil apparatus combined with synchrotron radiation. Both of the measurements with different techniques demonstrated that K-hollandite transforms to a new highpressure phase … Lire la suite
NEW PUBLICATION IN PHYSCIS OF FLUIDS For materials assumed to be simple yield stress fluids the velocity of an object should continuously increase from zero as the applied force increases from the critical value for incipient motion. We carried out … Lire la suite