Posez n’importe quelle question sur les cours, conférences, exercices, recherches, actualités, etc. de l’EPFL ou essayez les exemples de questions ci-dessous.
AVERTISSEMENT : Le chatbot Graph n'est pas programmé pour fournir des réponses explicites ou catégoriques à vos questions. Il transforme plutôt vos questions en demandes API qui sont distribuées aux différents services informatiques officiellement administrés par l'EPFL. Son but est uniquement de collecter et de recommander des références pertinentes à des contenus que vous pouvez explorer pour vous aider à répondre à vos questions.
During plasma excitation by high power Alfven waves at TCA, signals at harmonics of the generator frequency are observed in the plasma scrape-off layer. In this paper, experimental investigations of the sheath effect and the excitation efficiency and dispe ...
Pseudopotential calculations within density-functional theory for a few selected solids (Si, GaAs, and Al) are used to assess the validity of two generalized-gradient approximations (GGA's), the one proposed by Becke and Perdew (BP) and the more recent one ...
Longitudinal velocity measurements above a uniform dry lakebed were carried out to investigate the applicability of the random sweeping decorrelation hypothesis to thermally stratified turbulent flow. The higher order velocity structure functions of order ...
Aspects of shaped selective pulses and their applications in assignment and structure determination by NMR are considered. Specifically, strategies for the design of selective pulses for in-phase excitation are covered. In the simplest case, 270-degrees Ga ...
We develop a general quantum mechanical method to calculate the dispersion relations of polariton modes for a quantum well embedded in a semiconductor planar microcavity. The method is based on the properties of the Green's function;of the electromagnetic ...
Low-frequency losses in weakly anharmonic cubic centrosymmetric crystals as a function of permittivity are estimated using phonon kinetics approach. It is shown that very steep dependencies up to the fifth power of permittivity (epsilon'' is-proportional-t ...
We report on a transparent analysis of the luminescence spectra of dense electron-hole plasmas confined in GaAs/(Ga,Al)As quantum wells. We fit the spectra using the fact that the total number of particle states does not depend on collision broadening. Fur ...
The polariton Hamiltonian for a quantum well embedded in a cavity of finite width is derived. The exciton-light interaction is formulated in second quantization and the photon self-interaction term A2 is included. The importance of the A2 term turns out to ...
Frequency-modulated chirp pulses, for exciting multiple-quantum coherences over large bandwidths, can be considered as an alternative to composite pulses to combat the effects of large offsets and tilted effective fields. Refocusing of the phase dispersion ...
(Spectrospin A.-G., Switz.; Bruker Analytische Messtechnik G.m.b.H.).1992
Poloidal asymmetries in the electron density profiles and limiter diagnostics suggest that poloidal and toroidal flows exist in the SOL and edge plasma of the TEXTOR tokamak. A fast reciprocating probe located at the outer midplane provides profiles of the ...
