Most of NdBaCuO synthesis were realized under oxygen controlled melt growth (OCMG) which allows to avoid the solid solution formation. However, for industrial applications air synthesis is preferable due to its simplicity and its cost. In this work, different seeds and thermal cycles have been investigated in order to optimize the nucleation conditions for the obtention of a single domain. Several criteria have been defined for the choice of the seed. The solid solution Nd1+xBa2−xCu3Oy formed in these air synthesised samples appears in the range of x = 0.10 to 0.15, corresponding to $T_{\rm c_{onset}}$ between 60 K and 80 K. The nominal composition and the synthesis conditions (substrate, thermal treatments.) have to be accurately defined in order to avoid neodymium-rich solid solution formation.

Differential scanning calorimetry measurements under non-isothermal conditions were performed on the chalcogenide glasses Se98−x Sx Sn2 (x = 8, 18) and Se77 S20 X3 (X = Sn, Pb). The values of the glass transition temperature and crystallization temperature were found to depend on the heating rate. The activation energy for the glass transition and the activation energy for crystallization were calculated from the heating rate-dependence. The thermal stability and the glass forming tendency were calculated and they were found to have the same trend.

This work is concerned with the study of thermal expansion coefficient of Al-0.59 wt.% Mg-0.88 wt.% Si-0.30 wt.% Fe-0.44 wt.% Mn alloy. The presence of the anisotropy was concluded on the basis of the thermal expansion coefficient $\alpha(T)$ which depends up on the two directions: radial (1) and axial (2). However $\alpha(T)$ measured along the axial direction (2) appeared to be inferior to the measured one along the radial direction (1) in both as-cast and homogenised alloy.

We have performed atomic scale simulations of heteroepitaxial growth of thin films using the valence force field approximation and Monte Carlo techniques. The case of CdTe/(001)GaAs is considered. Our simulations indicate valley formation presenting (111) facets with unstable bottoms in the early stages of the growth. This roughening is a source of dislocation, as it appears to relax the elastic energy of the deposited layers by formation of V-grooves. We have used a calculated RHEED as an in situ control of deposited layers. Finally, we present the influence of an imperfect surface in the morphology of the deposited films.

The objective of the present study is to improve the modelling of heat transfer by elementary cells, aiming to increase the quality of their representation in the Laplace space. From the twoport representation and its connections with the classical nodal method, we show that the systematic increase of the order leads to improve the simulation results in transients. But, we would like to find a better reduced topology of the equivalent elementary network of heat conduction, closer to the analytical solution and verifying its terms for higher orders. The wall representation can be performed by an impedance network with “Π” or “T” shaped cells. The approximation of these impedances leads to define a new cell topology, which introduces capacitances with a negative value called "compensation capacitors". The value of these new elements only depends on the model nodal thermal capacitances in a wall. We study the transfer functions of these various equivalent networks as twoports that we will then compare to the analytical solution of the heat transfer equation. Some interesting values of the negative compensation capacitors are then obtained from transfer function; however, the optimal value would only be given from simulation results. All the established results will be confirmed by transient response simulations, which show the high performances of these new structures. These results are also validated by a modal analysis of these systems. The study of the model's accuracy show that the importance of the reduction for equivalent maximum errors corresponds to the square of the number of elementary cells.

An adaptive meshing technique is proposed. For a given number of nodes, the method allows a better precision, with a better repartition of the position of the nodes. It is based on the analysis of the influence of the node position and edge connection on the functional of the problem.

This paper presents two original types of SMES structures for energy storage. These two groups of SMES structures proceeded from an ideal structure: the full toroid, are modeled by the use of purely surface current densities. Their main advantage is to present no flux leakage, they give then satisfactory solution to the problem of energy storage.

In this paper we have studied the contribution of electrostatic and magnetic turbulence on particles anomalous transport in the tokamak. The diffusion coeffficient is evaluated. Comparison between diffusion magnetic field lines and particles is carried out. We also treat the effects of the reversed shear barrier in reducing the particles anomalous transport in the tokamak.

We have designed and built a liquid helium immersion insert which is magnetically shielded from the ambient magnetic field fluctuations by the use of a superconducting lead can. The insert has a variable temperature stage made of sapphire which is optically heated by the light guided from an external lamp via a glass rod. The temperature regulation is achieved by the use of a commercial PID controller: the temperature of the sapphire ranges from 50 K to 100 K with peak to peak fluctuations less than 20 mK over a 3 minutes observation period. The magnetic noise inside the insert has been measured with a low Tc dc-SQUID and the white noise level above 200 Hz is less than 4 fT/$\sqrt{\rm Hz}$. Furthermore, the magnetic attenuation factor due to the superconducting lead can is greater than 26 500 for frequencies above 15 Hz. This cryogenic insert is used for studying low frequency vortex noise in high Tc superconducting thin films at different temperatures and the field penetration in the films as a function of the applied magnetic field during its transition state.