Three chemical cleaning procedures for InSb(111) wafers were studied. X-ray photoelectric spectroscopy, and scan electron microscope were used to assess their credibility for use in manufacturing the InSb detectors. It is shown, a suitable thermal treatment can remove In oxide and Sb oxide and therefore, all procedures approach to similar results from this point of view. But undulation and peel-like features has been observed on InSb(111) surface etched by all etchants except a modified CP4A etchant (HNO3:CH3COOH:HF:H2O at 2:1:1:10). Also control the etch rate and etching process can be done better in CP4A than the others.The XPS results show different spectra for SbOx and InOx when, InSb(111) is compared with InSb(100) and it means that, for different crystal orientation and different etchant there are different cleaning method for removing SbOx and InOx .Finally the effect of etchants on the performance of InSb detectors was shown.

Solar blind detectors based on AlGaN heterostructures grown on sapphire by Molecular Beam Epitaxy and with a dielectric interference filter deposited on the back side are demonstrated to provide record spectral selectivity. Rejection ratios of 2 × 104, and better than 5 × 104, measured between 280 and 320 nm, are achieved in Metal Semiconductor Metal detectors and Schottky diodes respectively. The whole detector process is fully compatible with low cost array fabrication.

The aims of this article is presentation of a numerical simulation of the six degrees of freedom evolution of an inertial flywheel with high speed rigidly bound to a permanent magnet close a multifilamentaries superconductors winding. The simulation starts immediately after injecting an initial current in the winding and short circuiting it. We studied two configurations. One qualified as pendulum type in which the magnet is `suspended' to the winding and the other as a top type, the magnet `resting' on the winding. The simulation leads to a steady state conditions only for the pendulum type.

This work is a contribution to the understanding of mechanisms controlling the Atmospheric Pressure Glow Discharge (APGD). The approach consists in developing an electrical model of the discharge based on electrical circuit compounds. This model takes into account the main phenomena of the discharge including the memory effect and the creation of the cathode fall. It allows to have a general view of the process and can be easily associated to the power supply with short computational duration; it is also an interesting tool for the optimization of the whole process.

The first purpose of this work is to design a new observation technique for the Direct Torque Control (DTC). We put emphasis on robustness especially at very low speed, which represents the basic problem of the DTC operating, and on the optimization of the time computing. The reduced order observer is defined by decoupling the full order one in $\alpha $ and $\beta $ axis. The second basic aim of this paper is to apply the DTC strategy to multi-machine multi-inverter industrial systems. Speed and tension controls are designed; their performances and parameter robustness are analyzed and compared with those obtained with a Flux Oriented Control (FOC). Mechanical and electrical couplings constitute the principal operation difficulty of these systems mainly when one of the machines is perturbed.

The purpose of this paper is to describe the development and the use of two measurement techniques especially adapted to the rapid determination of the thermophysical properties of evolutive porous media. The first technique exploits the method of the “heated and non-heated wires” and is validated on wet clay by comparison with previous works [Mounanga et al., Eur. Phys. J. Appl. Phys. 26, 65 (2004)]. It is then used to quantify the evolution of both thermal conductivity and volumetric heat capacity of hardening cement pastes maintained at 294 ± 1 K. The second technique is based on the classical method of the “heating film” and a data treatment using forward calculation. This technique is first used to measure the properties of well-known materials (hardened mortars, wet sand [Mounanga et al., Eur. Phys. J. Appl. Phys. 26, 65 (2004); Delacre, Ph.D. thesis, University of Artois, 2000] and glass [Bastian, Rev. Phys. Appl. 22, 431 (1987)] and then applied to media whose properties evolve both over time and through space (drying sand).

We report on the characterization of the behaviour of an anisotropic magnetoresistive sensor undergoing a 100 kHz flipping of the magnetic domains, i.e. at frequencies two/three orders of magnitude higher than conventionally recommended. The noise analysis allows for the optimal setting of the relevant parameters defining such high-frequency, and hitherto unexplored, operation regime. Precision and accuracy performance in static conditions have been assessed by keeping into account the role of the sensor temperature. This last parameter has been evaluated by suitably manipulating the signals occurring at the sensor itself. The used technique can provide the base for a temperature sensor conditioning to be employed in magnetometers using this kind of devices.

We present the calculation of the impedance variation using a half-analytical formulation based on coupled electromagnetic variables. Such a formulation concerns an axisymmetrical device constituted with a voltage supplied solenoïdal inductor and a conducting workpiece. In this field of modelling, authors have already developed a method [Maouche and Feliachi, J. Phys. III France 10, 1967 (1997)] that determines the current distribution inside inductor coil loops in the case of weak skin depth and a low number of these coil loops. In the proposed development, the number of loops is relatively large and the skin effect in these loops is negligible. This formulation uses a voltage excitation, which makes the source field depending on induced currents and permits to consider the real geometry of the inductor. The model is applied to study an eddy current non destructive testing (ECNDT) device. The variation of the system impedance is calculated in the case of an axisymmetrical device. The obtained modelling results are validated by comparison to measurements and finite element computations [Rémy, Ph.D. thesis, University of Compiègne, France, 1997; La et al., Rev. Prog. Quant. Non-Destructive Eval. 16A, 295 (1997)]. Once validated, the proposed model is applied to determine geometrical and physical characteristics of an ECNDT device. To assemble this interest, we visualise the evolution of the impedance variation according respectively to the air-gap, to the thickness of the workpiece and its electric conductivity. The model is implemented within a software tool (CECM: Coupling Electromagnetic Circuits Method) developed in Matlab environment.

The heating rate effects in simulated liquid Al2O3 have been investigated by Molecular Dynamics (MD) method. Simulations were done in the basic cube under periodic boundary conditions containing 3000 ions with Born-Mayer type pair potentials. The temperature of the system was increasing linearly in time from the zero temperature as $T(t)=T_0 +\gamma t$ , where $\gamma $ is the heating rate. The heating rate dependence of density and enthalpy of the system was found. Calculations show that static properties of the system such as the coordination number distributions and bond-angle distributions slightly depend on $\gamma $ . Structure of simulated amorphous Al2O3 model with the real density at the ambient pressure is in good agreement with Lamparter's experimental data. The heating rate dependence of dynamics of the system has been studied through the diffusion constant, mean-squared atomic displacement and comparison of partial radial distribution functions (PRDFs) for 10% most mobile and immobile particles with the corresponding mean ones. Finally, the evolution of diffusion constant of Al and O particles and structure of the system upon heating for the smallest heating rate was studied and presented. And we find that the temperature dependence of self-diffusion constant in the high temperature region shows a crossover to one which can be described well by a power law, $D\propto (T-T_c )^\gamma $ . The critical temperature T c is about 3500 K and the exponent $\gamma $ is close to 0.941 for Al and to 0.925 for O particles. The glass phase transition temperature T g for the Al2O3 system is at anywhere around 2000 K.