High resolution neutron diffraction patterns of BaCex Zr1−x O3 (x = 0, 0.1, 0.4,0.8) were obtained at various temperatures. The phase diagram that was deduced from Raman measurements has been confirmed. Structural transitions occur in a fixed order Pnma-Imma- R $\bar{3}$ c-Pm3m as a function of temperature or composition. For BaCeO3, the large volume change that has been previously claimed at the Imma-R $\bar{3}$ c transition has been revisited and found inconsistent. For a given composition, the cell volume increases when temperature increases, but the MO6 (M=Ce-Zr) octahedron volume decreases. It is shown that the ratio of the cell volume to the octahedron volume is a good indicator of the phase transitions. Transitions occur at fixed values (5.77, 5.80 and 6 for the Pnma-Imma, Imma-R $\bar{3}$ c and R $\bar{3}$ c-Pm3m transitions respectively) independently of composition.

The evolution of the passivating layer (during the firstreduction/reoxidation cycle, in function of the number of reduction/reoxidationcycles and with the storage of the electrode in the electrolyte) formed at thesurface of a lithiated carbon electrode in LiCF3SO3/carbonates mixture electrolytehas been followed by using 1 MeV 4He+ induced Rutherford BackscatteringSpectrometry (RBS). Two RBS simulation codes "RUMP" and "PERM" , whose approachesare different, have been applied to the treatment of the RBS data and have allowedto obtain informations about the structure (thickness and atomic elementalcomposition) of the passivating layer. These two codes provide similar results. Thepassivating layer has a thickness in the range 20-30 nm. Its structure appears tobe complex with the presence of two different sublayers respectively composed of thereduction products of the salt in the inner sublayer (with the main presence offluorine and sulphur indicating the possible existence of LiF and Li2S) andreduction products of the solvents in the outer sublayer (with a high concentration in oxygen indicating the presence of Li2CO3 and RCO3Li where R is an alkylradical).

A luminescent study under selective photonic excitation has established thepresence of three different kinds of Ce3+ centres in SrS atomic layerepitaxy thin films: one in a regular sulfur octahedral sites and two others inlower symmetry. These last sites shift the emission spectra towards the green.High thermal annealing up to 750 °C improves the crystallinity of theSrS:Ce layer by converting low symmetry Ce3+ sites in regular octahedralsites and decreasing the density of defects. These two effects lead to efficientPL layers with a good blue chromaticity.

Dielectric and noise measurements versus frequency have been performed on a liquidcrystal in the paraelectric S A and ferroelectric $S^*_{\rm C}$ phases. A confrontation ofthese measurements is presented on the basis of the fluctuation-dissipation theoremwhich shows that these techniques both give similar results linked to theobservation of the classical soft mode and Goldstone mode in the S A and $S^*_{\rm C}$ phasesrespectively.

A pulse is solution of a boundary-initial value problem for the wave equation.We investigate the propagation in the z-direction of a Maxwell-Hopkinson dielectric of three kinds of pulses launched from the z = 0 plane at some time: harmonic plane wave, Bessel wave, distortion-free progressing wave. We prove that at high frequency, and as soon as the transient state has died out, these pulses propagate with an exponential attenuation factor in the direction of propagation.

The Dulkyn interferometer in Kazan is an active ring laser where the lightpropagates along two different paths. It has been developed with the ideathat it could detect low frequency gravitational waves on Earth.Considering Dulkyn as a detector of periodic strains of order of h ~ 10−22 at low frequencies (10−3 Hz−10−5 Hz) wecalculate that 30 W is the order of magnitude of the optical powernecessary to beat the photon noise in the case of a long observation time (T = 4 months) and a reasonable signal to noise ratio (r = 3). We estimatethat the displacement noise of the mirrors must not exceed 5×10−19m/ $\sqrt{{Hz}}$ .Dulkyn is also sensitive to accelerations and rotations. The accelerationnoise does not seem to be troublesome ( $\widetilde{g}\lesssim 0.1{m}{s}^{-2}/\sqrt{{Hz}}$ ), but the angular velocity noise must beless than 5×10−11 s−1/ $\sqrt{{Hz}}$ . The maximum strain (10−22) is obtained with free (pendulous) mirrors.Out of resonance, the strain is many orders of magnitude smaller when themirrors are fixed on a rigid support. Such a case would rule out thepossibility of a detection. As a conclusion we emphasize that the Dulkyndesign does not bring any decisive improvement for the detection of lowfrequency gravitational waves on Earth.

We have developed a model for the calculation of the induced current due to an electron beam with anextended generation profile. Added to the absorbed and diffuse electrons in the depth distribution, thegeneration profile takes into account the lateral diffusion. The analytical expression of the electron beam induced current (EBIC) is obtained by solving the continuityequation in permanent regime by the Green function method. The induced current profile, obtained in the case of a ternary component(Ga0.7Al0.3As:N+/Ga0.7Al0.3As:P) sulfur doped and prepared by organometalliccompounds phase vapor epitaxy method, is compared to the theoretical profiles whose analytical expressionsare given by Van Roosbroeck and Bresse. The experimental current profile, measured by S.E.M provided us to calculate the diffusion length of theminority carriers: L p = 1 µm in the N region and L n = 1.80 µm in the Pregion of the ternaire component. The theoretical curve obtained from the proposed model is in goodagreement with the experimental one for a surface recombination velocity of 106 cm s−1. Our resultsare found to be consistent compared to those obtained by other experimental techniques using the samesamples.

We have tried to understand the role of cellular tone (or internal tension mediatedby actin filaments) and interactions with the microenvironment on cellular stiffness. Forthis purpose, we compared the apparent elasticity modulus of a 30-element tensegritystructure with cytoskeleton stiffness measured in subconfluent and confluent adherent cellsby magnetocytometry, assessing the effect of changing cellular tone by treatment with cytochalasin D. Intracellular and extracellular mechanical interactions were analyzed on the basis of the non-dimensional relationships between the apparent elasticity modulus of the tensegrity structure normalized by Young's modulus of the elastic element versus: (i)element size, (ii) internal tension, and (iii) number of spatially fixed nodes, for smalldeformation conditions. Theoretical results and rigidity measurements in adherent cellsconsistently showed that higher cellular tone and stronger interdependencies with cellularenvironment tend to increase cytoskeleton stiffness. Visualization of the actin latticebefore and after depolymerization by cytochalasin D tended to confirm the geometrical andmechanical assumptions supported by analysis of the present model.

Temperature is an important parameter for industrial process control. With the usual methods we obtain only an invasive or superficial information about temperature. Microwave radiometry is a non-invasive way to determine the temperature within dissipative body. This paper presents the design of a new radiometer. With this system, the radiometric temperature is independent of the reflection coefficient of the sensor. A simplified calibration takes into account insertion losses of the microwave elements and the frequency bandwidth has been greatly reduced to eliminate the unwanted electromagnetic noise.

This article presents an application of a speckle interferometry technique with videodoubling, called "shearography". This technique can be used for near real time imaging of Lamb waves in continuous or burst modes, revealing the presence of delaminations in a carbon epoxy plate. The amplitude of the displacements is measured with a typical uncertainty of the order of 1 nm. The nominal Lamb wave can be suppressed from the shearographic image by optical filtering, to show only the wave interaction with any defects that may exist in the plate. This method is especially advantageous for non-destructive testing.

The study concerns remote controlled sensors, associating micro-mechanical and microwave data communicationfunctions. A radio link can be used to transmit information from the sensor as well as to provide internalpower supply. Applications include Wireless Sensor Networks projects. An important operation is performedthrough a passive microwave frequency shifter used for retransmission. Two structures of this frequencyshifter using silicon membrane micro-mechanical capacitors are described, with further details concerning the optimisation of the dimensions using electro-mechanical modellisation, the problems in technologicalsilicon implantation, and some first experimental results.

The characteristics of the various modes of acoustic waves (velocity, attenuation, efficiency) radiated towards the focused sensor of an acoustic microscope are related to the acoustic properties of the coupling fluid. The aqueous solutions of electrolytes are suitable as coupling fluids because their acoustic properties can be adjusted owing to the choice of the nature and of the concentration of the dissolved ions. By adjusting the properties of the couplant, the performances of the sensors of the acoustic microscopes can be extended. The image contrasts and the accuracy of measurements of the acoustic waves velocity are improved, the radiation of the chosen modes are enhanced and very high frequencies can be used.