Search

SmCo5 thin films with different thicknesses were prepared by electron beam evaporation on Kapton substrates. The out-of-plane hysteresis loops for different thicknesses reveal a maximum coercive field when the thickness is 15 nm. Using random magnetic anisotropy model, the thickness dependence of magnetic properties was studied in SmCo5 nanocrystalline films and several fundamental magnetic parameters were extracted. We have determined the local magnetic anisotropy constant K 1 which is found to increase with increasing film thickness except for t = 7 nm which is thought to arise from the structural imperfection of the SmCo5 films.

In this study, SmCo-based films with different thicknesses were grown on a Kapton substrate by ultra-high vacuum (UHV) evaporation process. Two effects on magnetic properties of SmCo films have been investigated: the effect of the variation of the magnetic layer thickness and the effect of the substrate temperature. The morphology and the structure were explored by atomic force microscopy and X-ray diffraction. It has been shown that the film morphology and its crystallographic orientation changed significantly with increasing thickness. Magnetic measurements reveal a strong correlation between magnetic and structural properties. The highest magnetic squareness ratio M r/ M s (0.8) and a maximum coercive field at room temperature, of about 2 kOe, are obtained when the SmCo layer thickness is 15 nm.

In the current study, we aim at simulating via a detailed Monte Carlo code, the electron penetration in a semi-infinite indium medium for incident energies ranging from 0.5 to 5 keV. Electron range, backscattering coefficients, mean penetration depths as well as stopping profiles are then reported. The results may be seen as the first predictions for low-energy electron penetration in indium target.

Based on a home-made Monte Carlo simulation, the electron backscattering coefficient, mean penetration depth, transmission probability, and transmission energy distribution of 1–5 keV electron normally incident penetrating in indium thin film targets have been computed. The trend of all features of interest as a function of the indium film thickness at both nanometric scale region and bulk material region has been examined and discussed. The present predictions may be seen as the first investigation regarding 1–5 keV electrons impinging on indium thin film targets. Copyright © 2016 John Wiley & Sons, Ltd.

Analytical expression of the target atomic number dependence of the numerical coefficient in the Nigam atomic screening factor is proposed here to approximate the Rutherford elastic scattering cross sections for slow electron beams impinging on selected solid targets (from Be to Au) in the primary energy range 1–4 keV. Applications are then proposed in terms of Monte Carlo calculation of backscattering coefficient. In this respect, tabulations of backscattering coefficients are here reported for slow electrons in solid targets of interest pointing out a reasonable agreement with the data available in the literature. Analytical expressions of the target atomic number dependence of the electron backscattering coefficient is also suggested for selected electron primary energies ranging from 1 to 4 keV allowing thus an accurate determination of backscattering coefficients for low-energy electrons in solid targets without any resort in Monte Carlo type calculations.

The aim of this work is to study the dielectric properties of thin films of tungsten trioxide. WO3 is an interesting material in the field of gas sensors. Here, we investigate the dependence of the electrical conductivity with temperature as well as the effect of the pressure on the thermal activation energy. For this purpose, we have used Impedance Spectroscopy (IS) to study the dielectric properties of RF sputtered WO3 thin films. Particularly, we have emphasized the effect of oxygen pressure on the surface conductivity.

On sait qu’une courbe algébrique standard d'équation f(x, y) =0 admet un nombre fini de branches (nombre inférieur à l'ordre de f ), dont les paramètrages peuvent être obtenus en particulier à partir de la décomposition de Goze itérée. On aimerait calculer leur courbure généralisée sans les déterminer explicitement, la notion de courbure généralisée ayant fait l’objet d’un travail, publié dans les comptes rendus de l’Université de Cagliari (Italie) [12]. Dans cet article, on se propose d'établir à cet effet un algorithme qui donnera à partir seulement des coefficients de f, la liste exhaustive des courbures généralisées de toutes les branches réelles. L’article se termine par la donnée d’un exemple pour montrer l’efficacité de l’algorithme proposé.

L'objet de cet article est l'étude du comportement local d'une cubique dans le halo d'un point régulier ou singulier. Pour cela, on utilisera le fait que tout point limité deadmet un développement fini (décomposition de Goze). Ceci nous permettra d'étudier la géométrie tangentielle en ce point et le comportement analytique de la cubique autour de ce même point en donnant un paramétrage dans une direction tangentielle. Cette approche est faite dans le cadre des ensembles internes (Analyse Non Standard).

The present study investigates the formulation and use of solid-shell finite element models which are able to model thin and thick, isotropic and multilayered composite structures using a purely 3D formulation based only on displacement dof. The second part of the paper deals with the optimization of composite structures, using a specific response surface method. This technique has been shown to be more efficient than classical gradient based methods. Several applications combining our solid-shell finite element model and the specific response surface method are shown in order to assess current procedure capabilities.

The benefits of surgical correction of mitral incompetence were assessed in 51 patients by comparing pre and postoperative catheter and quantitative angiographic results. The mean age of the patients was 43.5 +/- 12.3 years. The mitral lesions were elongation or ruptured chordae (27 cases), valvular perforation due to endocarditis (1 case) and the usual rheumatic disease in 23 cases. Hemodynamic investigation was carried out on average 2 months before operation and 29 +/- 22 months after surgery. The following angiographic parameters were measured : indexed end diastolic and end systolic volumes (EDV and ESV), ejection fraction (EF), myocardial mass (MM) and its ratio to EDV (hypertrophy coefficient : HC) and the geometry of the ventricle as assessed by diastolic and systolic coefficients of excentricity (DE and SE). Surgery comprised 13 mitral valvuloplasties and 38 valve replacements. Patients who suffered perioperative myocardial infarction or who had a residual valvular lesion were excluded from the study. After surgery, the hemodynamic state was considerably improved with a significant decrease in pulmonary capillary pressures (11 +/- 5 compared to 17 +/- 6 mmHg, p less than 0.09) and mean pulmonary artery pressures (19 +/- 7 compared to 27 +/- 11, p less than 0.01) and increase in cardiac index (2.8 +/- 0.7 compared to 2.3 +/- 0.6 l/min/m2, p less than 0.01). There was an associated decrease in ventricular volumes (EDV : 115 +/- 44 compared to 165 +/- 43, p less than 0.01) (ESV : 60 +/- 39 compared to 77 +/- 22, p less than 0.001). The reduction in myocardial mass was less spectacular (129 +/- 40 compared to 148 +/- 32, p less than 0.01) with a resulting increase in the HC (1.10 +/- 0.26 compared to 0.88 +/- 0.17, p less than 0.001). The geometry of the LV was less spherical in diastole (DE 0.76 +/- 0.08 compared to 0.70 +/- 0.08, p less than 0.001) and in systole (SE = 0.83 +/- 0.06 compared to 0.77 +/- 0.08, p less than 0.001). The EF fell slightly but this was not statistically significant (0.51 +/- 0.13 compared to 0.53 +/- 0.09 NS). The surgical result of 14 patients with PCP greater than or equal to 13 mmHg was considered hemodynamically incomplete, and this was confirmed by a lower cardiac index than in the remaining 37 patients (2.4 +/- 0.5 compared to 3.0 +/- 0.7, p less than 0.01).(ABSTRACT TRUNCATED AT 400 WORDS)