Thin films of cadmium selenide (CdSe) were grown by the chemical bath deposition (CBD) technique. The effects of the common grain growth promoter, cadmium chloride (CdCl2) and annealing on the films were investigated. X-ray diffraction (XRD), high-resolution scanning electron microscopy (HRSEM), atomic force microscopy (AFM) and energy dispersive X-ray spectroscopy (EDS) measurement techniques are used to determine the crystalline structure, surface morphology and composition of the as-deposited and annealed films. Noticeable changes in XRD patterns were observed on the annealed films. The as-deposited films of poor crystalline quality are transformed into crystalline hexagonal phase of CdSe. The annealing and CdCl2 treatment affects the grain growth, which is stronger for the CdCl2 treated samples. The optical properties of the films were investigated by optical transmittance and photoluminescence (PL) spectroscopy. The optical band gaps of the films are estimated using the optical transmittance measurements. A decrease in the band gap is observed for the annealed films with or without CdCl2 addition. Photoluminescence peak intensity due to the near band edge luminescence is found to increase with annealing and it increases pronouncedly by annealing with CdCl2 treatment. This effect can be attributed to the enhancement of the crystallinity of the films. Nevertheless, films annealing after CdCl2 treatment resulted in selenium vacancies, which display a band emission centred at 1.4 eV.

Benefits from laser Peening have been demonstrated several times in fields like fatigue, wear or stress corrosion cracking. However, in spite of recent work on the calculation of residual stresses, very few authors have considered a finite element method (FEM) approach to predict laser-induced mechanical effect. This comes mainly from the high strain rates involved during LP (106 s−1), that necessitate the precise determination of dynamic properties, and also from the possible combination of thermal and mechanical loadings in the case of LP without protective coatings. In this paper, we aim at presenting a global approach of the problem, starting from the determination of loading conditions and dynamic yield strengths, to finish with FEM calculation of residual stress fields induced on a 12% Cr martensitic stainless steel and a 7075 aluminium alloy.

Barium metaplumbate thin films were deposited in situ by pulsed laser deposition on Si/SiO2/Ti/Pt substrates with a high deposition rate. The temperatures used ranged between 400 °C and 700 °C. As the deposition temperature was increased, the films assumed a strong (222) preferential orientation. This orientation of the electrodes was reflected on the PZT films, having a very big influence on their ferroelectric behavior. The PZT films made over BPO deposited at high temperature presented high values of remanent polarization (43 μC/cm2) but indications of high leakage currents could be observed in the hysteresis loops. By using BPO bottom electrodes, a 30% improvement in the fatigue behavior of PZT capacitors when compared with the normal platinum electrodes was observed.

The matching method is used to analyse the scattering of elastic waves by a structural defect made up several atomic chains surmounting an infinite lattice plane. The vibrational dynamics of the structure is considered within the harmonic approximation framework. The propagating continuum associated to the two vibrational eigenmodes of the perfect lattice is determined and discussed. The localised states induced by the defect are calculated and analysed for heavy and light adatom masses. Their interest appears during the investigation of the diffusion spectra. These localised states allow the interpretation of some observed structures in terms of Fano resonances. It is shown that the resonance number decrease in transmission spectra of light adatom case. The Fano resonances can be absent in the transverse mode, but are always present in the longitudinal one. Their position shifts slightly towards the high frequencies when the number N of perturbating chains increases. When N is higher than the unity, oscillations of Fabry-Perot type appear in the transmission spectra. The number of these oscillations is directly related to the number of adatomic linear chains, in the light and heavy mass cases, in both eigenmodes. We also observe the existence of zeros transmission in the spectra. Because of the large size of the dynamical matrices and complicated graphical resolution spectra, we have limited our study to eight perturbating adatomic linear chains.

In this paper a new method of stator-core lamination characterization, aimed at studying magnetic field in the vicinity of a machine, is proposed. This characterization, made with small signals over a wide frequency range, is useful to study high frequency magnetic behavior of motors fed by PWM static converters. Small minor hysteresis loops of magnetic steel are assimilated to ellipses and, neglecting anisotropy, any point of a stator-core lamination is characterized by two local parameters: the relative permeability and the resistivity. The proposed method consists in measuring the impedance of a test coil over a wide frequency range by an impedance analyzer and in comparing experimental results to theoretical predictions based on magnetic field diffusion equation. An algorithm yields values of local relative permeability and resistivity from inductance measurements and experimental values of resistances are used to control the result quality.

Co3O4 thin films were prepared via the Pechini method using spin-coating and sintering processes. X-ray diffraction (XRD), atomic force microscopy (AFM), and Raman spectroscopy were employed to characterize the films. The XRD pattern from the prepared films can be indexed based on a spinel structure. Ordered crystalline columns and high quality surfaces are observed via the AFM images. It is found out that the grain size increases with the sintering temperature. Minimum roughness of the film can be obtained at PEG content 60 mg/ml. Raman spectroscopy confirms that the films are crystallized in the spinel structure. A red shift observed in all bands shows that the cohesive energy is lower in the film than in the bulk crystal.

We present a systematic analysis, within the scope of electromagnetic theory, of the spectral moments method (SMM) and develop several ways to compute the linear response of any type of system. We show that the method can be used in diffraction studies regardless of the number, nature and form of the diffracting objects. Multiple diffraction is naturally taken into account in the computation. The method can thus be applied to determine propagation through any type of media. It is based on the computation of Green functions, solutions of discretized Maxwell's equations. Fourier transforms of Green functions are developed in continued fraction. Two approaches will be presented. In the first “global” approach, all space is discretized, the coefficients of continued fractions are computed directly from the dynamic matrix obtained by the discretization of Maxwell's equations and from sources and receivers. In the second “local” approach, only the diffracting system is discretized. This paper is devoted to the global approach. We study two important problems in electromagnetism, i.e. propagation of a plane wave through a heterogeneous layer and scattering of an isolated object. We present two computation techniques for plane wave propagation: one uses a small grid, is very rapid but the results are approximate; the other uses a large grid, is less rapid but the results are exact. We show that computing the reflectivity and/or transmissivity of photonic lattices is now a very simple problem. For scattering, we mainly report a series of tests on some canonical systems, such as cylinders or spheres, showing that SMM results are in very good agreement with the analytical results. Several types of absorbing boundary conditions are tested. We report results on backscattering cross-sections and the impulsional response of different one-, two- and three-dimensional systems.

The aim of this paper is to provide data on the influence of the geometry of the fins on the acceleration performance of a ram accelerator projectile in the subdetonative mode. The data that are presented in this paper are derived from a non reacting computation performed at the French Research Institute (ISL) with the commercial numerical code TascFlowTM from AEA Technology. This code calculates the pressure and temperature profiles in a non-reactive flow around the ram accelerator projectile. Three types of projectiles were studied with respectively three, four and five fins. Furthermore, different fin geometries were studied. The wall temperature behavior was investigated, in order to explain the high erosion of the projectile that is observed as the projectile comes out of the tube. Moreover, the high temperatures that were derived from the calculation explain the initiation process of the reactive at some point of the projectile, which, in turn, explains the unstart process. These calculations were conducted during ram accelerator operations at ISL and were used to explain some effects observed on the experimental data obtained in both the 30-mm and 90-mm caliber facilities.