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A previous analysis of the average intensity and mean-square intensity difference of Friedel opposites, confined to the space group P1 [Flack & Shmueli (2007). Acta Cryst. A63, 257–265], is here extended to all the noncentrosymmetric space groups. The prese ...
The superspace concept is a new crystallographic approach for the generalisation of symmetry, structural models and structure dependent properties. Although the original motivation for the superspace was intended to describe symmetry of aperiodic crystals, ...
The theories used up to now to model theoretically and numerically nanostructures, and more specifically semiconductor heterostructures, do not allow to include efficiently at the envelope function level, in a k · p approach, the effects imposed by a possi ...
A new method for space-group determination is described. It is based on a symmetry analysis of the structure-factor phases resulting from a structure solution in space group P1. The output of the symmetry analysis is a list of all symmetry operations compa ...
The pyroelectric coefficients of 0.72Pb(Mg1/3Nb2/3)O-3-0.28PbTiO(3) (PMN-28PT), 0.67Pb(Mg1/3Nb2/3)O-3-0.33PbTiO(3) (PMN-33PT), and 0.92 Pb(Zn1/3Nb2/3)O-3-0.08PbTiO(3) (PZN-8PT) single crystals, oriented and poled along three different crystallographic dire ...
We present a symmetrization algorithm for geometric objects. Our algorithm enhances approximate symmetries of a model while minimally altering its shape. Symmetrizing deformations are formulated as an optimization process that couples the spatial domain wi ...
Strontium barium niobate (SrxBa1-xNb2O6, shortly SBN) is a solid solution system with tetragonal tungsten bronze crystal structure. It exhibits a ferroelectric phase with only one polar axis and a transition temperature depending on the Sr/Ba ratio. This t ...
The incommensurately modulated twinned crystal structure of lazurite from the Baikal region is presented for the first time. The orthorhombic structure was solved in a pseudo cubic unit cell, a(cub) = 9.077(1) Angstrom, and in the (3 + 2)D superspace group ...
[Rh-4 (CO)(6) (mu-Me2PCH2PMe2)(3)], the first example of a hexasubstituted derivative of Rh-4(CO)(12), has a ground state geometry in the solid state and in solution of C-s symmetry with four edge-bridging carbonyls and with each diphosphine ligand bridgin ...
As observed by variable-temperature and -pressure C-13 NMR, intramolecular carbonyl scrambling in Ir2Rh2(CO)(12) and Ir-4(CO)(11)(mu-SO2) proceeds via a 'change of basal face' mechanism. In both cases the site exchange process has a positive activation vol ...
