Measurements of the complex susceptibility, $\chi(\omega)=\chi'(\omega)-{\rm i}\chi''(\omega)$, as a function of the frequency (100 Hz–18 GHz) and polarizing field (0–90 kA m−1) at room temperature together with static magnetic measurements over the temperature range 4–300 K, are reported for a colloidal suspension of cobalt nanoparticles. The transition of the cobalt particles to the superparamagnetic state are supported by the temperature dependencies of field cooling (FC) and zero field cooling (ZFC) magnetization measurements. From these measurements, which show a typical blocking behaviour of an assembly of superparamagnetic particles with a wide distribution of blocking temperatures, the exponential pre-factor $\tau_0$ of Brown's equations for Néel relaxation, is found to be equal to 9.2 × 10−10 s. Measurement of the complex susceptibility $\chi(\omega)$ over this broad frequency range, with an upper frequency value corresponding to three times that previously reported in our measurements on cobalt, has enabled the presence of both resonance and Néel relaxation mechanisms to be identified. From the Néel component, a further value for $\tau_0$ was evaluated and shown to be in close agreement with that obtained from the ZFC data. Data on the after-effect function, realised by Fourier transformation of the $\chi''(\omega)$ component, is also presented.

An analytical model for the effective magnetic properties of a thin film consisting of a few layers of particles with arbitrary permeability and the stochastical initial magnetization is presented. The model is magnetostatic and implies the explicit averaging of the true field. It is shown that it works for all possible thicknesses of the film (arbitrary number of particles across the film) and there is no need for surface-to-bulk transition. The surface effect leading to the change of the reflective properties of the thin film compared to the prediction of the traditional theory is significant for a sparse arrangement of the grains and vanishes when these are touching. The method is verified by comparison with the model of the lattice of magnetic scattering centers.

The reflection and transmission of optical videopulses incident axially upon a slab of a chiral sculptured thin film (STF) is studied using a finite-difference simulation in the time domain. Videopulse bleeding is shown to occur when the handedness of the carrier plane wave matches the structural handedness of the chiral STF and the carrier wavelength lies in the Bragg regime.

The eddy current sensor method is widely used to evaluate conductive parts. The eddy current measurements are very sensitive to the variations of the sensor positioning relatively to the part under evaluation, which can disturb consequently such evaluation. The effect of the variation of the positioning of a sensor having an U-shaped magnetic core has been studied by 3-D finite element computations. The results show that the tilt and the lift-off of the sensor relatively to the part under evaluation induce similar straight lines in the normalized impedance plane. Consequently their effect can be corrected fairly thanks to a single processing. This notably allows to reduce the sensor handling during its calibration as well as the calibration time.

The magneto-thermo-mechanical behavior of metals in inductive heating devices is investigated by means of numerical calculations. The goal of this paper is to attract attention to necessity of mechanical problems solution for inductive heating technology and to develop three-dimensional and two-dimensional (axisymmetrical) mathematical models, coupling algorithm and software for such computations. The paper presents a finite element formulation, based on an indirect coupling model of electromagnetic, thermal and static elastic-plastic mechanical processes in treated workpieces in inductive heating devices. The effect of electromagnetic, thermal and mechanical material properties depending on temperature is taken into account. The presented numerical technique is applied for technological problems of practical interest.

We have simulated the experimental spectroscopic charge pumping technique by the implementation of a model in the electrical simulator SPICE3F4. This model takes into account the temperature effect on the geometrical and electrical parameters of the studied transistor. The simulated results are in a good agreement with recent and different experimental results.

The purpose of this paper is to highlight the impact of thinning on low and high levels DC characteristics of SmartMOS LDMOS devices. Both subthreshold and saturation current voltage deviations are discussed.

In this paper we have studied the contribution of reversed shear in reducing the anomalous transport in a Tokamak using both an analytical approach and simulations. We have used a special model for the drift wave fields. Comparison between particles trajectories for normal and negative shear is carried out. The diffusion coefficient of particles for the two cases; normal and reversed shear is evaluated.

From the Helmholtz free energy, the pressure, the mole fraction, the internal energy and the specific heat capacity at constant volume in temperature range of 1 000 to 20 000 K in the plasma formed of insulator vapours of PC and POM for various densities (0.05 kg/m3 to 5 kg/m3) and at LTE are calculated. The virial and Debye-Hückel corrections on pressure are discussed. The graphite formation is studied.

The purpose of the present study was to apply knowledge of structural properties to perform numerical simulations with models of bones and knee ligaments exposed to dynamic tensile loading leading to tissue damage. Compact bones and knee ligaments exhibit the same geometrical pattern in their different levels of structural hierarchy from the tropocollagen molecule to the fibre. Nevertheless, their mechanical behaviours differ considerably at the fibril level. These differences are due to the contribution of the joints in the microfibril-fibril-fibre assembly and to the mechanical properties of the structural components. Two finite element models of the fibrous bone and ligament structure were used to describe damage in terms of elastoplastic laws or joint decohesion processes.

With a laboratory built X-ray microscope, analysis of a thermal diffusion process in a KBr solution has been performed. A solution of a salt submitted to a constant temperature gradient gives rise to a stationary concentration gradient of the species after a few hours: this is the so called Soret effect. From the digital image of the liquid, acquired in the steady state of the process, it is easy to obtain the concentration map of the species in the solution. The average concentration profile then deduced permits to reach the value of the Soret coefficient and the heat of transport of the binary compound. X-ray radiography is an alternative powerful technique to analyse this kind of complicated phenomenon where composition matter fluxes are driven by both temperature and composition gradient.

A simple EDXRF technique to obtain the relative concentrations of different elements present in a sample is described here. Only those elements have been considered whose characteristic X-rays fall within the sensitivity range of the X-ray detector that we used. A small computer program where the fundamental parameters such as photoionisation cross sections, fluorescence yields, Coster-Kronig transition rates, etc. have been used as inputs was written to calculate the relative concentrations of the elements. The technique used here requires only a single run with the sample and does not require any knowledge of the incoming X-ray flux or geometry of the experimental arrangement. Using this method, three alloys have been analysed in our existing EDXRF system.