Penser la relation d’aide et de soin à partir du handicap: enjeux et ambivalences.

International audienceCet article est l'éditorial d'un premier numéro spécial de la revue Alter sur la thématique "Care et handicap". Un deuxième numéro suivra. Ces deux numéros spéciaux de la revue Alter autour de la thématique « care et handicap » ont pour objectif de prolonger le débat et le dialogue initiés entre différents courants de pensée sur la nature de la relation d’aide, sur ses effets en termes de qualification et de définition des personnes (aidantes comme aidées), sur ses ambivalences et tensions inhérentes. Ils reviennent notamment sur le débat entre Disability Studies et Ethique du care

Analysis of thermal detrapping of holes created by electron irradiation in high purity amorphous SiO2 using the induced and secondary current measurements

International audienceIsothermal detrapping of holes after electron irradiation (using a SEM) in high purity amorphous SiO2 is evaluated at different temperatures (in the range 300-663 K) by means of the induced and secondary current measurements. In order to single out the hole detrapping, the specific charging conditions (1 keV defocused electron beam of low density) leading to positive charging are adopted. The thermal detrapping, which stems from a single trap, begins at 523 K and is completed at 663 K. After annealing in air at 973K during 48h, two detrapping stages are revealed: the former is connected with an additional shallow trap, while the latter requires temperatures above 663 K for a complete detrapping. The first order kinetics describes reasonably well the detrapping process. The frequency factors (near 10(10) s(-1)) and the activation energies (about 1.6 eV) deduced from this analysis could be assigned, respectively, to the relaxation connected to detrapping and to the trap energy level of the charged oxygen vacancy. (C) 2015 Elsevier B.V. All rights reserved

Analytical description of mirror plot in insulating target

A method has been developed to link the geometry of the trapped charge distribution within irradiated insulators to the mirror plot shape, in a scanning electron microscope. We give a detailed analysis of the geometrical optic approximation which is used to evaluate the mirror image formation. We establish then analytical mirror relations obtained for diverse trapped charge distributions such as homoïdal charge distribution, bipunctual and cylindrical ones. Knowledge of the charge distribution first moments enables us to investigate then their effect on the first terms of the mirror expression limited development. Finally, we apply these analytical expressions to evaluate certain characteristics of the charge distribution from an experimental mirror plot

Modeling of secondary electron emission and charge trapping in an insulator under an electronic beam

International audienceCharge accumulation in an insulator, as achieved by electron irradiation in a SEM, is governed by complex phenomena. The understanding of the relevant processes (the generation of free carriers, transport and trapping/de-trapping) is a prerequisite for the design of materials having improved breakdown strengths. A simple modeling, which meets the planar geometry conditions, is proposed. The predictions of the evolution of secondary electron emission yield (as function of the quantity of trapped charges) agree well with the experimental results at room temperature, in pure amorphous SiO2. The agreement is obtained with trapping cross-sections near 10-10 cm2, which are much higher than the typical values (about 10-16 cm2). Trapping appears as an “effective” process that reflects the Brownian motion of secondary electrons

Charge injection modeling and initial SE yield by two fluxes method; New source term of secondary electron generation by Monte Carlo simulation

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