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The heteronuclear cross-polarization efficiency in the rotating frame can be improved by sweeping the radiofrequency amplitude adiabatically through the Hartmann-Hahn condition. The enhancement is particularly significant for strongly coupled IS spin syste ...
This work is dedicated to the study of Dynamical Systems, depending on a slowly varying parameter. It contains, in particular, a detailed analysis of memory effects, such as hysteresis, which frequently appear in systems involving several time scales. In a ...
In the scope of the study of low-frequency electrostatic microinstabilities in tokamak plasmas, attention has been focused on the effect of trapped ions. The ballooning transform has been applied to the gyrokinetic equation, for the case of a large aspect ...
The electron states of weakly-one-dimensional quantum wires are computed using the adiabatic approximation in the framework of the k . p theory and the envelope-function approximation. The computed transition rates of electrons from one confined state to a ...
A weakly-onedimensional heterostructure is a quantum wire structure tailored so that the carriers are tightly confined in a direction, weakly confined in another and free to move in the third. The electronic bound states are computed using the envelope fun ...
A fully two-dimensional study of the electronic sub-bands in crescent-shaped quantum wires is presented. The confinement energies and the wave functions are compared by means of an aspect ratio to those produced by the adiabatic approximation. Guidelines f ...
The second law of thermodynamics is often expressed as the fact that the entropy of an isolated system increases when a spontaneous change takes place. While this statement is true, a more general formulation can easily be presented to students. Starting f ...
We consider the transition probability for two-level quantum-mechanical systems in the adiabatic limit when the Hamiltonian is analytic. We give a general formula for the leading term of the transition probability when it is governed by N complex eigenvalu ...