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International audience; In this work, we propose an optimization scheme based on a multi-objective Genetic Algorithm (GA) for the design of orthogonal filter banks for speech compression. A parameterization is adopted to assure that the resulting filter banks satisfy perfect reconstruction and have at least two vanishing moments. We search for a parameter set that optimizes the coding gain and the frequency selectivity. As the objectives are conflicting, we investigate the solution that realizes the best compromise between the objectives criteria using the Non-dominated Sorting Genetic Algorithm (NSGAIII). Experimental results have shown that the optimized filter banks provide a significant gain in coding performances when comparing with the Daubechies orthogonal filter banks for test speech signals.

International audience; Un-doped, Zn-doped, and Al–Zn co-doped CdO thin films were deposited onto glass substrates at 350 °C by spray pyrolysis. X-ray diffraction (XRD) analysis was conducted to investigate the structural properties of the films. The XRD patterns confirmed that all the films crystallize in a cubic structure and that the addition of Zn and Al did not alter the CdO crystal structure. Energy-dispersive X-ray spectroscopy analysis further confirmed the successful incorporation of Zn and Al into the CdO films. Theoretical calculations based on first-principles were performed, and crystallographic information files (CIF) were obtained for optimized theoretical supercells in space group Pm3-m. The CIF files were used as input for experimental XRD spectra Rietveld refinement, to determine the Wyckoff positions of the dopants and their occupation rates. The optical properties of the films were characterized using transmittance measurements in the wavelength range of 300–1700 nm. The optical data indicated an increase in the average transmittance from 60 to 70% within the wavelength range of 600–1700 nm upon Al–Zn co-doping. The estimated direct optical band gap of the un-doped, doped, and co-doped CdO thin films is varied between 2.41 and 2.50 eV. All the samples exhibited n-type conductivity with low electrical resistivity of about 1.32 × 10–4 Ω⋅cm. Co-doped CdO thin films with 1% Al and 3% Zn exhibited higher carrier concentration (4.39 × 10+20 cm−3) than the other samples.

International audience

This research aimed to assess the adsorption properties of raw walnut shell powder (WNSp) for the elimination of methylene blue (MB) from an aqueous medium. The initial MB concentration (2–50 mg/L), the mass of the biomaterial (0.1–1 g/L), the contact time (10–120 min), the medium’s pH (2–12), and the temperature (25–55 °C) were optimized as experimental conditions. A maximum adsorption capacity of 19.99 mg/g was obtained at an MB concentration of 50 mg/L, a medium pH of 6.93 and a temperature of 25 °C, using 0.2 g/L of WNSp. These conditions showed that the MB dye elimination process occurred spontaneously. Different analytical approaches were used to characterize the WNSp biomaterial, including functional groups involved in MB adsorption, the surface characteristics and morphological features of the WNSp before and after MB uptake, and identification of WNSp based on their diffraction pattern. The experimental isotherm data were analyzed by the Langmuir and Freundlich models for the adsorption of MB dye. The corresponding values of parameter RL of Langmuir were between 0.51 and 0.172, which confirmed the WNSp’s favorable MB dye adsorption. The experimental kinetic data were examined, and the pseudo-second-order model was shown to be more suitable for describing the adsorption process, with an excellent determination coefficient (R2 = 0.999). The exchanged standard enthalpy (H° = −22.456 KJ.mol−1) was calculated using the van ‘t Hoff equation, and it was proven that the adsorption process was exothermic. The spontaneous nature and feasibility of the MB dye adsorption process on WNSp were validated by negative standard enthalpy values (G°) ranging from −2.580 to −0.469 at different temperatures. It was established that WNSp may be employed as a novel, effective, low-cost adsorbent for the elimination of methylene blue in aqueous solutions.

International audience; Strengthening concrete beams by prestressed or not prestressed composite plates has become one of the widely used techniques in civil engineering with the aim of improving the durability of infrastructures, specifically against seismic solicitations. However, this type of reinforcement is quite new for prestressed concrete beams. Before using a composite plate for strengthening prestressed concrete beams, it is important to know its dynamic characteristics. In this paper, an analytical model based on the high-order theory and the laminate theory is proposed in order to well determine the free vibration characteristics of presetressed composite plate. The presence of prestressing tension effort in the composite plate, which was not taken into consideration in earlier studies for slender composite plates, is the main innovation of the current research. Parametric studies varying prestressing effort and fiber orientations are carried out in aim to find the best way to use the composite plate in the reinforcing of prestressed concrete beams. For comparative purposes, a finite element model is carried out in order to explore the behavior of the composite plate under several boundary conditions (B.Cs). As an important result, this research reveals that prestressing effort stiffens the composite plate and makes it a strong choice for reinforcing prestressed concrete beams by increasing natural frequencies and reducing deflexion. © 2023 Elsevier Ltd

The simple random walk on $\mathbb{Z}^p$ shows two drastically different behaviours depending on the value of $p$: it is recurrent when $p\in\{1,2\}$ while it escapes (with a rate increasing with $p$) as soon as $p\geq3$. This classical example illustrates that the asymptotic properties of a random walk provides some information on the structure of its state space. This paper aims to explore analogous questions on space made up of combinatorial objects with no algebraic structure. We take as a model for this problem the space of unordered rooted trees endowed with Zhang edit distance. To this end, it defines the canonical unbiased isotropic random walk on the space of trees and provides an efficient algorithm to evaluate its escape rate. Compared to Zhang algorithm, it is incremental and computes the edit distance along the random walk approximately 100 times faster on trees of size 500 on average. The escape rate of the random walk on trees is precisely estimated using intensive numerical simulations, out of reasonable reach without the incremental algorithm.

International audience; Non-orthogonal multiple access (NOMA) has been identified as a potential fundamental shift for the design of multiple access systems. Over a high Doubly Selective (DS) channel scenario, this paper considers the use of NOMA system based on Multi-Carrier Modulation (MCM) with various waveforms, with Orthogonal Frequency Division Multiplexing (OFDM) and Filter Bank Multicarrier Modulation (FBMC) as special cases. Furthermore, we investigate the Imperfect Successive Interference Cancellation (I-SIC). NOMA users are affected by intra-user interference and inter-user interference in this situation. To this end, an adaptive receiver scheme that combines one-tap equalization and a joint iterative interference cancellation, proposed in literature, is introduced. The receiver selects the appropriate data detection mechanism based on the power allocation factor and hence the channel constraints. The One-Tap equalizer is so useful in practice. Unfortunately, once the DS channel and NOMA induced interference begin to dominate the noise, a one-tap equalization under-performs. On the other hand, by using the joint iterative interference cancellation approach, performance will be greatly improved at the cost of computational complexity. Moreover, numerical simulations are carried out to illustrate the efficacy of the suggested combined strategy in contrast to the theoretical Perfect-SIC (PSIC) condition.

Background The importance of apolipoprotein E (APOE) in lipid and lipoprotein metabolism is well established. However, the impact of APOE polymorphisms has never been investigated in an Algerian population. This study assessed, for the fist time, the relationships between three APOE polymorphisms (epsilon, rs439401, rs4420638) and plasma lipid concentrations in a general population sample from Algeria. Methods The association analysis was performed in the ISOR study, a representative sample of the population living in Oran (787 subjects aged between 30 and 64). Polymorphisms were considered both individually and as haplotypes. Results In the ISOR sample, APOE ϵ4 allele carriers had higher plasma triglyceride (p=0.0002), total cholesterol (p=0.009) and LDL-cholesterol (p=0.003) levels than ϵ3 allele carriers. No significant associations were detected for the rs4420638 and rs439401 SNPs. Linkage disequilibrium and haplotype analyses confirmed the respectively deleterious and protective impacts of the ϵ4 and ϵ2 alleles on LDL-cholesterol levels and showed that the G allele of the rs4420638 polymorphism may exert a protective effect on LDL-cholesterol levels in subjects bearing the APOE epsilon 4 allele. Conclusion Our results showed that (i) the APOE epsilon polymorphism has the expected impact on the plasma lipid profile and (ii) the rs4420638 G allele may counterbalance the deleterious effect of the ϵ4 allele on LDL-cholesterol levels in an Algerian population.

International audience; A model of two microbial species in a chemostat competing for a single resource in the presence of an internal inhibitor is considered. The model is a four-dimensional system of ordinary differential equations. Using general growth rate functions of the species, we give a complete analysis for the existence and local stability of all steady states. We describe the behavior of the system with respect to the operating parameters represented by the dilution rate and the input concentrations of the substrate. The operating diagram has the operating parameters as its coordinates and the various regions defined in it correspond to qualitatively different asymptotic behavior: washout, competitive exclusion of one species, coexistence of the species, bistability, multiplicity of positive steady states. This bifurcation diagram which determines the effect of the operating parameters, is very useful to understand the model from both the mathematical and biological points of view, and is often constructed in the mathematical and biological literature.

International audience; Density functional calculations in periodic boundary conditions (PBCs) were performed to investigate the structural and electronic properties of neutral and charged M@C60 (M = Li, Na, or K). Minimal energy structures for each compounds were obtained. The structural analysis shows that the geometrical shape of the endohedral fullerenes is not perfectly spherical. In the periodic boundary conditions, only K and K+ retain their position in the center of fullerene while (Li) and (Na) are shifted from the center by 1.53 and 0.89 Å respectively. Mulliken population analysis indicated that the M-C60 bond may be purely ionic in the case of encapsulated K and Na, and partly ionic in the case of Li. For all compounds, the highest occupied cluster orbitals (HOCOs), the lowest unoccupied cluster orbitals (LUCOs) and the Gap energy were calculated and compared with literature.The results obtained using PBCs approach show that the simulation model used in this study is indeed appropriate, it not only agrees very well with other theoretical methods but also is consistent with experimental results for C60. Furthermore, this model provide new Gap values for (M@C60) compound (M = Li, Na, or K) that can be used by the scientific community for deriving other electronic properties.

International audience; In this paper, buckling and free vibration of imperfect, functionally graded beams, including porosities, are investigated, using a higher order shear strain theory. Due to defects during the manufacturing process, micro porosities may appear in the material, hence the appearance of this imperfection in the structure. The material properties of the beams are assumed to vary regularly, with power and sigmoid law, in the direction of thickness. A novel porosity distribution affecting the functionally graded volume fraction is presented. For the compact formulation used for cementite-based materials and already used in P-FGM, we have adapted it for the distribution of S-FGM. The equations of motion in the FG beam are derived using Hamilton's principle. The boundary conditions for beam FG are assumed to be simply supported. Navier's solution is used to obtain the closed form solutions of the FG beam. The numerical results of this work are compared with those of other published research to verify accuracy and reliability. The comparisons of different shear shape functions, the influence of porosity, thickness and inhomogeneity parameters on buckling and free vibration of the FG beam are all discussed. It is established that the present work is more precise than certain theories developed previously. Copyright © 2022 Techno-Press, Ltd.

In this paper, two Schottky structures of Au/n-GaAs (sample A) and Au/0.8 nm-GaN/n-GaAs (sample B) were fabricated and electrically characterized by current–voltage measurements at different temperatures. Two models, a classical one and another previously proposed named Helal model ref (Helal et al. Eur Phys J Plus, 135:1–14, 2020). Both the models show that the ideality factor n grows as the temperature decreases, and the second model shows higher values especially at low temperatures. The barrier height $$\Phi_{b}$$ Φ b calculated using the second model decreases when temperature increases for both structures, according to the temperature-dependent band gap, and in contrast to the results obtained by the classical model. Moreover, the second model gives a homogeneous Schottky barrier height and the best resolution of Richardson constant $$A^{*}$$ A ∗ , for both structures. On the other hand, the classical model shows an inhomogeneity of the barrier height and very far values of $$A^{*}$$ A ∗ from the theoretical one, in both structures. The findings of this study support the validity and dependability of the proposed alternative model. Furthermore, it may give a new insight into the electrical behavior of the Schottky structures.

International audience; Three plants adopted by nomads at Tassili n’ajjer (south Algeria) in traditional medicine namely,Cymbopogon schoenanthus, Anabasis articulata and Salvia chudaei, were analysed for theirs antibacterial, antibiofilm and antioxidant properties. Total flavonoid and phenolic contents were measured with 2% AlCl3 and Folin-Ciocalteu’s reagent method, respectively. The antibacterial propertie was investigated by measurement of MIC of plants extract inhibing bacterial proliferation. The antibiofilm propertie was calculated by fluorescent quantization of the DAPI labeled bacterial biomass fixed on the surface and by COMSTAT analysis of confocal scanning laser microscopy (CSLM) images. DPPH radical scavenging and β-carotene/linoleate bleaching methods were used to determine the antioxidant activities of the plants. Total phenolic content was ranged from 21.98 to 2.51 (gallic acid equivalents mg/g methanolic extracts) and the total flavonoid content ranged from 19.27 to 1.65 (catechin equivalent mg/g methanolic extracts). Antibacterial activity against four Gram positive bacteria was shown with plants extracts. The biofilm inhibition concentration of extracts decreasing 50% of biofilm cell density (BIC50) for Salvia chudaei and Cymbopogon schoenanthus extracts ranges from 1 to 10 μg/mL. CSLM images analysis revealed that both surface covering by germ and three dimensional development of the biofilm were reduced with plants extracts. For antioxidant activities, the methanol extracts of the plants evaluated showed low antioxidant activity, with a IC50 between 1.94 and 6.16 mg/ml. Thus, Our systematic research showed that this three common plants of Sahara desert has diversified phytochemicals possessing satisfying extent of antimicrobial, antibiofilm and antioxidant activities.

International audience

International audience; The Internet of Things (IoT) allows communication between devices, things, and any digital assets that send and receive data over a network without requiring interaction with a human. The main characteristic of IoT is the enormous quantity of data created by end-user’s devices that needs to be processed in a short time in the cloud. The current cloud-computing concept is not efficient to analyze very large data in a very short time and satisfy the users’ requirements. Analyzing the enormous quantity of data by the cloud will take a lot of time, which affects the quality of service (QoS) and negatively influences the IoT applications and the overall network performance. To overcome such challenges, a new architecture called edge computing — that allows to decentralize the process of data from the cloud to the network edge has been proposed to solve the problems occurred by using the cloud computing approach. Furthermore, edge computing supports IoT applications that require a short response time and consequently enhances the consumption of energy, resource utilization, etc. Motivated by the extensive research efforts in the edge computing and IoT applications, in this paper, we present a comprehensive review of edge and fog computing research in the IoT. We investigate the role of cloud, fog, and edge computing in the IoT environment. Subsequently, we cover in detail, different IoT use cases with edge and fog computing, the task scheduling in edge computing, the merger of software-defined networks (SDN) and network function virtualization (NFV) with edge computing, security and privacy efforts. Furthermore, the Blockchain in edge computing. Finally, we identify open research challenges and highlight future research directions.

Electrostatic adhesion (EA) technique have been used recently for the electrostatic sorting of metal/polymer granular material mixture. The action seat on the materials is an EA actuator composed of an interposed electrodes network covered by a dielectric barrier and powered by polyphase voltages. The sorting principle consists of attaching the metal particles by EA, and of moving the polymer particles larger than 500 μm, mainly by gravity and vibration. The purpose of this paper is to optimize the EA mechanism for electrostatic sorting. The first part consists of evaluating the behavior of materials (Cu, PE, and PVC) on the EA actuator surface using a 180°-rotating system. The results showed that the metal attaches to the actuator surface while the polymer does not; they also indicate the optimal factors contributing to the adhesion process. In the second part related to sorting application, the granular materials behavior and the influencing factors are explored in an inclined vibrating system to process a Cu/PVC mixture. For an inclination of 10°, Cu recovery on the actuator exceeds 98% with a purity of about 99%.

International audience; The nature of H-bonds in κ-carrabiose⋯Y (Y = HF, HCl, HBr, NH3, H2O, and H2S) complexes was studied. For this aim, the structure of isolated κ-carrabiose was optimized using three global hybrids functional: B3LYP, PBE0, and M06-2X combined with 6-311G** basis set. Subsequently, the κ-carrabiose in the presence of HF, HCl, HBr, NH3, H2O, and H2S was optimized using the CBS-4 M method. NBO analyses were then carried out at the MP2/6-311G** level of theory. A particular interest was focused on C(18)―H(34)⋯Y bond. The results reveal that the C(18)―H(34)⋯Y bond is an improper H-bond since a significant contraction of C(18)―H(34) was observed during the complexation leading to a significant blueshifted stretching frequency. The NBO analyses have shown that the formation of the improper H-bonds C(18)―H(34)⋯Y (Y = F, Cl, Br, N, O, and S) is principally due to the increase of the s-character of the hybrid orbital in carbon atom (rehybridization) in κ-carrabiose⋯Y complexes. Regarding the polarization, it was proved that more the H-bond center (carbon in C(18)―H(34)⋯Y) becomes less positive, the hydrogen more positive, and Y more negative; more the contraction of the C(18)―H(34) bond is important. It was also confirmed for intramolecular H-bonds in κ-carrabiose⋯Y complexes that the rehybridization is responsible for H-bonds nature either proper or improper.

International audience; The efficiency of electrical energy has become the most important elements in the part of electrical and electronic systems partially in the lighting systems, for this reason the light-emitting diode (LED) lamps are widely used in recent years. Nevertheless, LED is a non-linear load which causes a very high harmonic current, and a low power factor PF, thus a poor power quality. Research is focused on reducing current harmonics and improving the power factor (PF) has intensified. In this paper, a comparative study between Passive Power Factor Corrector (PPFC) with different topologies and Active Power Factor Corrector (APFC). These types were modeled using the LTspice software and the input power factor (PF) and total harmonic distortion (THD) of each type is determined and analyzed.

International audience; Electromagnetic interference (EMI) represents one of the biggest problems facing the production of any electronic device. The impact on the performance of the device caused such unwanted interference must be carefully measured to understand and quantify the electromagnetic compatibility (EMC) of the instrument under test. The electrical power conversions are among the sources of electromagnetic pollution, they provide a low power factor and generate electromagnetic interference (EMI). The white light emitting diode (LED) has attracted a lot of attention from industry and scientific researchers due to its high efficiency, easy of driving, and long life. Nevertheless, LED driver can interfere with the electronic device system due to rapid voltage variation and current. In this paper we simulate some LED driver topology on LTspice software in order to measure the electromagnetic disturbances using LISN (line impedance stabilizer network) device.

International audience; In this paper, we propose an experimental and numerical model to study the creep behavior of the unidirectional Alfa fiber composite strength by the photoelasticity method. To have better mechanical properties, chemical treatment is made for Alfa fibers. Tensile tests are made to predict the Young modulus and tensile strength. These tests confirm that the chemical treatment during 48 Hours of Alfa fibers collected from the south region gives the best results. After that, specimens are made in Medapoxy STR resin and treated Alfa fibers of the south region. All fibers of specimens are arranged approximately in multiple hexagonal clusters embedded in the matrix. For the micromechanical fiber stress redistribution or load sharing theory to be applied, clusters must minimally contain one broken fiber. Consequently, we have a stress perturbation due to a fiber fracture, which propagates to the nearest-neighbor fibers. This perturbation enables us the photoelastic visualization of the fracture events during the creep tests. The contour diagram and fringe values give us the accurate distribution of stress near broken fibers showing local shear stress concentrations during the time. To simulate the creep response and failure mechanism, the Tsai–Wu failure criterion was applied on ANSYS explicit dynamic software. Because it merges between experimental tests and numerical simulation, the present study offers a real scientific contribution in the creep behavior of biobased composite strength by the photoelasticity method.

International audience; Domesticated cereals (wheat, rice, corn, barley) contribute considerably to human nutrition providing energy, protein, micronutrients, vitamins, and antioxidants. In wheat, starch and protein accumulate in the endosperm whereas most of the phytonutrients are found in the aleurone layer (AL). The AL is the outermost layer of the endosperm and is removed with the bran in conventional milling. Many studies have been devoted to analyze this living tissue in cereal seeds, particularly in wheat. However, breeders still need to consider genetic and environmental factors that influence its properties and composition. The present survey focuses on recent advances achieved through proteomic and transcriptomic studies on the aleurone tissue. The origin of the AL in cereals, its mineral composition, antioxidants, nutrients and vitamins, the accumulation of globulins, and its major functions have been particularly highlighted. Studies dealing with the genetic factors involved in the variability of the AL components have also been emphasized. Improving the nutritional and health value of wheat for consumers is primordial. The present review proposes some approaches that could be developed through the AL traits breeding to improve the nutritional and health value of future wheat.

In the present paper, we investigate the existence, uniqueness, regularity and continuous dependence of mild solutions to a fractional diffusive logistic equation with memory in Bessel potential spaces, through Banach fixed point theorem and Gronwall inequality.

International audience; No abstract available

Epoxy/ITO nanocomposites containing various filler ITO concentrations by weight were successfully fabricated. Using Differential Scanning Calorimetry (DSC), a thermo-analytical technique used to study the glass transition temperatures, we expected to find a restriction in the molecular mobility of the polymer chains that might confirm the influence of incorporating ITO contents into the epoxy material. Several complementary techniques were investigated, such as dielectric relaxation spectroscopy (DRS) at the range of frequency (10−1–106) Hz and over the temperature range from − 80°C to 240°C, and time-domain spectroscopy (TDS) with frequency domain (10−5–10−1) Hz. The experimental data were investigated and interpreted in terms of various dielectric formalisms. For TDS results, the neat epoxy is affected by the added ITO nanoparticles. In the low-frequency domain of TDS measurements, the depolarization current curves of the nanocomposites are precisely fitted in a parallel circuit (RiCi) association model. The obtained dielectric data of TDS analysis shows two interfacial relaxation processes. The first wide peak was mainly ascribed to the charge accumulations ITO-polymer interfaces and the additional peak can be related to the charge accumulated at the interface material-electrodes. Impedance evaluated data were analyzed using a consistent electrical circuit formalism. From − 80°C to 60°C, the nanocomposites exhibited an ohmic behaviour within the added ITO nanofiller. Between 60°C and 120°C, the nanocomposites exhibit a capacitive contribution behavior which makes the material suitable for capacitors devices. Above 120°C, the Nyquist design illustrations [(− Z″) versus (Z′)] are well theoretical fitted to an equivalent circuit model achieved by impedance with designed parameters: resistance (Rb) and constant phase element (CPE) combinations.

International audience; Collected by honeybees, Bee pollen is a flower pollen gathered from selected flower species by special pollen traps, therapeutic qualities and reproductive performance of bee pollen are given from biologically active substances. Lead is a heavy metal, which induce reproductive intoxication, comes in the high levels from human activities. The aim of the present study was to evaluate the impact of bee pollen hydro-ethanolic extract on adult Wistar rat tes-tis exposed to lead acetate sub-acute intoxication (15 days), highlighted using histological technics in situ. The biochemical and biometric measurement were conducted to verify any eventual toxicity of hydro-ethanolic extract in vivo. Animals were divided into four equal groups: first control group was treated orally with distillated water (1 ml) by gavage. The second group was administered 100 mg/kg/bw/day of a hydro-ethanolic extract of bee pollen, the third group was administered 30 mg/kg/bw/day lead acetate, the fourth group was given the both treatments in the same levels. The results showed that the relative organs weight indicates that only left kidney (p=0.001) and spleen (p=0.001) were attenuated without a considerable difference of the liver (p=0.07). the same was shown for relative weight of sexual organs. In addition, no significant difference, was marked, in serum biochemical parameters except for: Blood urea nitrogen, Alanine aminotransferase, Total biliru-bin and Direct bilirubin. furthermore, ameliorative effect was shown after lead-induced alteration after histological stain of seminiferous tubules, indicating low lumen of seminiferous tubules with presence of spermatogonia and wide height of seminiferous epithelium. Biologic activities of bee pollen extract, alleviate the lead induced toxicity on rat testis, marked by a complete spermatogenesis and prevention of Sertoli cells destruction.; Rassemblé par les abeilles, le pollen d'abeille est un pollen de fleur recueilli à partir d'espèces de fleurs sélectionnées par des pièges à pollen spéciaux, les qualités thérapeutiques et les performances de reproduction du pollen d'abeille sont données à partir de substances biologiquement actives. Le plomb est un métal lourd, qui induit une intoxication reproductive, provient à des niveaux élevés des activités humaines. Le but de la présente étude était d'évaluer l'impact de l'extrait hydro-éthanolique de pollen d'abeille sur les testicules de rats Wistar adultes exposés à une intoxication subaiguë à l'acétate de plomb (15 jours), mis en évidence à l'aide de techniques histologiques in situ. Les mesures biochimiques et biométriques ont été effectuées pour vérifier toute toxicité éventuelle d'un extrait hydro-éthanolique in vivo. Les animaux ont été divisés en quatre groupes égaux : le premier groupe témoin a été traité par voie orale avec de l'eau distillée (1 ml) par gavage. Le deuxième groupe a reçu 100 mg / kg / pc / jour d'un extrait hydro-éthanolique de pollen d'abeille, le troisième groupe a reçu 30 mg / kg / pc / jour d'acétate de plomb, le quatrième groupe a reçu les deux traitements dans le même les niveaux. Les résultats ont montré que le poids relatif des organes indique que seuls le rein gauche (p = 0,001) et la rate (p = 0,001) étaient atténués sans différence considérable du foie (p = 0,07). Il en a été de même pour le poids relatif des organes sexuels. De plus, aucune différence significative n'a été marquée dans les paramètres biochimiques sériques, à l'exception de : l'azote uréique sanguin, l'alanine aminotransférase, la bilirubine totale et la bilirubine directe. En outre, un effet améliorateur a été montré après une altération induite par le plomb après coloration histologique des tubules séminifères, indiquant une faible lumière des tubules séminifères avec présence de spermatogonies et une grande hauteur d'épithélium séminifère. Les activités biologiques de l'extrait de pollen d'abeille, atténuent la toxicité induite par le plomb sur les testicules de rat, marquée par une spermatogenèse complète et la prévention de la destruction des cellules de Sertoli.

International audience; Novel functional Schiff base ligands bearing pyrrole moieties in their structures, L1:1-(3-Pyrrole-1-yl-propylimino-methyl)-naphtalen-2-ol, L2:1-(3-Pyrrole-1-yl-propylimino-methyl)-phenol and L3: 1-(3-Pyrrole-1-yl-phenylimino-methyl)-naphtalen-2-ol as well as their Cu(II) complexes, have been synthesized and characterized by means of common spectroscopic analysis methods such as FTIR, UV-Vis, 1H NMR, 13C NMR, GC-MS and thermogravimetric analysis (TGA). The complexes, along with their metallic centres, were electropolymerized by the cyclic voltammetry method on platinum (Pt) and indium tin oxide (ITO) substrates, so that new and original modified electrodes (MEs) could be obtained, i.e. ME Poly(Li-Cu)Pt and ME Poly (Li-Cu)ITO (i=1-3). MEs obtained on ITO were characterized by FTIR spectroscopy and their morphology was investigated using scanning electron microscopy (SEM) and elemental composition by EDX analysis. The catalytic activity of these modified electrodes was successfully evaluated using electroreduction reactions in aqueous media of organic substrates. The efficiently of acetophenone reduction was significantly improved by increasing the quantity of added substrate. The value of cathodic current intensity ipc goes up from 7 to 42μA for substrate volume values varying from 0 to 40 μL, respectively. In addition, a significant increase of current values from -70μA to 175μA was observed in the presence of a saturated solution of CO2.

In this paper, a stable optofluidic Fabry-Perot (FP) resonator consisting of silicon cylindrical Bragg mirrors combined with a central capillary-tube is investigated. The cylindrical Bragg mirrors provides an in-plane confinement of light while the central capillary tube full of fluid improves the out-of-plane light confinement. Through the Finite-Difference Time-Domain (FDTD) technique with perfectly matched layers (PMLs) absorbing boundary conditions, a sensitivity of 592 nm per refractive index unit (RIU) with a detection limit (DL) of less than 10−3 RIU is obtained for liquid refractometry. For gas refractometry, a sensitivity of 1053 nm per refractive index unit (RIU) with a detection limit (DL) of 5 × 10−4 RIU is achieved. Such sensitivity is, to our knowledge, the highest ever reported for an RI gas refractometer based on stable optofluidic FP resonator. The proposed device has promising performances which suggest its potential use in future sensing applications.

International audience; (SnS)m(Sb2S3)n thin films were prepared by thermal evaporation using the glancing angle deposition technique (GLAD). The incident angle between the particle flux and the normal to the substrate was fixed at 80°. The Raman and XRD characterization revealed the amorphous character of the films due to the columnar structure as shown by the SEM characterization and AFM analysis. A strong change of the surface morphology of the films was observed and it depends on the composition. Optical properties were extracted from transmittance T and reflectance R spectra. (SnS)m(Sb2S3)n thin films exhibit high absorption coefficients (104–2 × 105 cm−1) in the visible range and the higher values were obtained for Sn3Sb2S6 and it has the highest photocurrent values. The direct band gap (Eg dir) was in the range 2.11–1.67 eV. The refractive indices are calculated from optical transmittance spectra of the films. The Sn3Sb2S6 sample exhibits a lower refractive index. All the dispersion curves of refractive index match well with the Cauchy dispersion formula and they were analyzed using Wemple-DiDomenico model. The Bruggeman effective medium approximation EMA was used to calculate the packing density of different compositions, and SnSb4S7 sample has the highest value. The so-called Verdet coefficient was evaluated from refractive index dispersion, and it was enhanced near the band gap.

In this paper, we consider an Euler-Bernoulli beam equation with time-varying internal fluid. We assume that the fluid is moving with non-constant velocity and dynamical boundary conditions are satisfied. We prove the existence and uniqueness of global solution under suitable assumptions on the tension of beam and on the parameters of the problem. Afterwards, we establish the exponential stability of the solution by introducing a suitable Lyapunov functional., 15 pages, 1 figure

International audience; In this work, Aliquat 336 ([Aliquat+]) based ionic liquids containing the fluorinated anion bis(trifluoromethylsulfonyl)imide [NTf2−] was successfully prepared by the anionic exchange replacement of the chloride anion. The reaction of lithium bis(trifluoromethylsulfonyl)imide with N-Methyl-N,N,N-trioctylammonium chloride ([N1,8,8,8][Cl] in water lead to the corresponding IL, namely ([Aliquat+][NTf2−]). The obtained ionic liquid was characterized by using infrared and Raman spectra and its structure was confirmed by 1H-NMR, 13C-NMR, and 19F-NMR. The thermal properties were investigated by two complementary thermal analysis techniques: TGA and DTA. A hexadentate coordination mode between cation-anion was predicted by atoms in molecules (AIM) studies for the [Aliquat+][NTf2−] IL by using B3LYP/6-31G* calculations where three O atoms of the anion in Cis conformation are linked to six H atoms of cation by S-O•••H interactions. Changes in the bond orders of S and O atoms of the cation supported such observations. The predicted cation-anion distances were in the range 2.30-2.60 Å. The harmonic force fields of cation and anion were calculated and the complete assignments were performed for both species while the most important bands observed in the infrared and Raman spectra of the IL were assigned. In addition, the scaled force constants of cation and anion of the IL were also reported.

International audience; Egg shell (ES) is a biological macromolecule mainly containing calcite embedded in proteins and polysaccharides, while shell membrane predominantly contains proteins. Thus ES with membrane (ESM) possesses richer protein contents than ES. In the present work, ES and ESM have been separately modified using mono-and di-cationic imidazolium ionic liquids, [C 5 mim + ][Br-] (IL) and [Bis-(PhCH 2 MIm) + ][2Cl-] (DIL). Thus four modified products have been obtained namely ES-IL, ES-DIL, ESM-IL and ESM-DIL. In order to determine physico-chemical modifications of the ES due to the interactions with the ionic liquids, the structural, spectroscopic and thermal properties of all products were investigated by means of XRD, FTIR and TG/DTA. The IR spectra display significant changes in the 1400-1550 and 2800-3100 cm-1 regions confirming the insertion of IL and DIL into the ES and ESM layers. Furthermore, the XRD results indicate that this modification process influence the crystal structure of the ES. Thermal analysis suggests that the chemical modification increases the thermal stability of the ES and ESM. It has also been ascertained that presence of proteins in the shell membrane is responsible for increasing thermal stability in the order ES < ESM < ES-IL < ESM-IL < ES-DIL < ESM-DIL.

International audience; In this paper hyperbolic shear deformation plate theory is presented for bending and the free vibration of functionally graded plates with considering porosities that may possibly occur inside the functionally graded materials (FGMs) during their fabrication. Four different porosity types are used for functionally graded plates. Equations of motion are derived from Hamilton's principle. In the solution of the governing equations, the Navier procedure is implemented. In the numerical examples, the effects of the porosity parameters, porosity types and geometry parameters on the bending and free vibration of the functionally graded plates are investigated. It was found that the distribution form of porosity significantly influence the mechanical behavior of FG plates, in terms of deflection, normal, shear stress and frequency. © 2021 Techno-Press, Ltd. All Rights Reserved.

Computer vision is defined as a field of computer science that enable automatic systems to identify visual inputs. These systems are usually used to perform recommendation tasks. In recent years, the amount of digital data, such as images and videos, have largely increased. In this regard, the exploitation of computer vision systems became essential to maintain these volumes and also to extract relevant information. Computer vision systems are based on machine learning (ML) and deep learning (DL) methods. Many factors, such as the growing volumes of data and the availability of powerful graphical processing units (GPU) have encouraged the computer vision community to exploit DL methods. These techniques are characterized by their efficiency on large volumes of data and also by their capacity to extract features from non-structured data. DL methods have been exploited in different applications in computer vision to perform several tasks: classification, localization, detection, and segmentation.In this study, we are particularly interested in the classification of histopathological images by convolutional neural networks (CNN). In this context, we have proposed several pipelines to solve the different issues related to the application of DL methods on these types of images. The proposed frameworks are based mainly on regularization methods, ensemble learning techniques, and transfer learning and fine-tuning strategies. We should note that ensemble learning techniques are used to solve the different issues related to the high variance, overfitting, and the sensevity of neural networks to data changes. On the other hand, transfer learning and fine-tuning strategies are used to solve the overfitting problem on limited volumes of data; La vision par ordinateur est un champ d’étude qui permet aux systèmes automatiques à reconnaitre les entrées visuelles pour les exploiter dans des tâches de recommandation. Dans ces dernières années, la quantité des images et des vidéos a largement augmenté. L’exploitation des systèmes de vision par ordinateur pour l’analyse de cette quantité d’informations devient importante afin d’extraire de l’information pertinente. Les systèmes de vision par ordinateur sont basés essentiellement sur les méthodes d’apprentissage automatique (ML) et d’apprentissage profond (DL). Avec l’augmentation de la quantité de données et la disponibilité du matériel puissant, les méthodes DL ont connu un grand intérêt en raison de leur bonne performance sur les grands volumes de données et leur capacité d’extraction de caractéristique dans le cadre des données non structurées. Ces techniques étaient exploitées dans différents sous domaines en vision par ordinateur pour effectuer plusieurs tâches : classification, localisation, détection, et segmentation. Dans le contexte de la présente étude, nous nous intéressons à la classification des images histopathologiques par les méthodes DL, précisément par les réseaux de neurones convolutifs (CNN). Dans ce cadre, nous avons proposé plusieurs approches pour répondre aux différents problèmes liés à l’application des techniques DL en classification de ce type d’images. Les approches proposées sont basées essentiellement sur les techniques de régularisation, les méthodes ensemblistes, et les stratégies d’apprentissage transféré et de fine tuning. Il est intéressant de noter que les méthodes ensemblistes sont exploitées afin de résoudre les différents problèmes liés à la variance élevée, le sur-apprentissage, et la sensibilité des réseaux DL au changement de données. En plus, elles permettent de combiner les prédictions de plusieurs modèles, et cela génère des décisions plus robustes et stables au changement de données. D’autre part, les techniques d’apprentissage transféré et de fine tuning sont utilisés afin de résoudre le problème de sur-apprentissage sur les volumes limités de données.

Computer vision is defined as a field of computer science that enable automatic systems to identify visual inputs. These systems are usually used to perform recommendation tasks. In recent years, the amount of digital data, such as images and videos, have largely increased. In this regard, the exploitation of computer vision systems became essential to maintain these volumes and also to extract relevant information. Computer vision systems are based on machine learning (ML) and deep learning (DL) methods. Many factors, such as the growing volumes of data and the availability of powerful graphical processing units (GPU) have encouraged the computer vision community to exploit DL methods. These techniques are characterized by their efficiency on large volumes of data and also by their capacity to extract features from non-structured data. DL methods have been exploited in different applications in computer vision to perform several tasks: classification, localization, detection, and segmentation.In this study, we are particularly interested in the classification of histopathological images by convolutional neural networks (CNN). In this context, we have proposed several pipelines to solve the different issues related to the application of DL methods on these types of images. The proposed frameworks are based mainly on regularization methods, ensemble learning techniques, and transfer learning and fine-tuning strategies. We should note that ensemble learning techniques are used to solve the different issues related to the high variance, overfitting, and the sensevity of neural networks to data changes. On the other hand, transfer learning and fine-tuning strategies are used to solve the overfitting problem on limited volumes of data, La vision par ordinateur est un champ d’étude qui permet aux systèmes automatiques à reconnaitre les entrées visuelles pour les exploiter dans des tâches de recommandation. Dans ces dernières années, la quantité des images et des vidéos a largement augmenté. L’exploitation des systèmes de vision par ordinateur pour l’analyse de cette quantité d’informations devient importante afin d’extraire de l’information pertinente. Les systèmes de vision par ordinateur sont basés essentiellement sur les méthodes d’apprentissage automatique (ML) et d’apprentissage profond (DL). Avec l’augmentation de la quantité de données et la disponibilité du matériel puissant, les méthodes DL ont connu un grand intérêt en raison de leur bonne performance sur les grands volumes de données et leur capacité d’extraction de caractéristique dans le cadre des données non structurées. Ces techniques étaient exploitées dans différents sous domaines en vision par ordinateur pour effectuer plusieurs tâches : classification, localisation, détection, et segmentation. Dans le contexte de la présente étude, nous nous intéressons à la classification des images histopathologiques par les méthodes DL, précisément par les réseaux de neurones convolutifs (CNN). Dans ce cadre, nous avons proposé plusieurs approches pour répondre aux différents problèmes liés à l’application des techniques DL en classification de ce type d’images. Les approches proposées sont basées essentiellement sur les techniques de régularisation, les méthodes ensemblistes, et les stratégies d’apprentissage transféré et de fine tuning. Il est intéressant de noter que les méthodes ensemblistes sont exploitées afin de résoudre les différents problèmes liés à la variance élevée, le sur-apprentissage, et la sensibilité des réseaux DL au changement de données. En plus, elles permettent de combiner les prédictions de plusieurs modèles, et cela génère des décisions plus robustes et stables au changement de données. D’autre part, les techniques d’apprentissage transféré et de fine tuning sont utilisés afin de résoudre le problème de sur-apprentissage sur les volumes limités de données.

International audience

International audience; Three new substituted dicationic ionic liquids (DILs) based on biphenylenedimethylene linked bis-1-methylimidazolium ionic liquids [Bis-(PhCH 2 MIm) + ],combined with three anions, namely dichloride[Cl] 2 , di(hexafluorophosphate) [PF 6-] 2 and di(bis(trifluoromethylsulfonyl)Imide) [(CF 3 SO 2) 2 N-] 2 were synthesized. The three synthesized dicationic ionic liquids were characterized by Nuclear Magnetic Resonance and Fourier transform infrared (FTIR) and Raman spectroscopy in the region 4000-600 cm −1 and 4000-45 cm −1 , respectively. A complete vibrational assignments have been performed; the biphenylene linkage spacer is confirmed by the presence of strong Raman band at 1616 cm-1 related to the C=C vibration in all our investigated DILs. Moreover, a conformational investigation of the cation was performed by means of DFT calculations using the 6 31G** basis set and the B3LYP theory. The comparison of the computed and experimental Raman spectra further corroborate the structure of the cation. Finally, the thermal stability of the DILs was investigated by TGA and DTA measurements. The DILs with Cl-, PF 6-and [(CF 3 SO 2) 2 N-] anions decompose at 252, 323 and 420 °C, respectively.

A model of plasmid-bearing and plasmid-free organisms in a chemostat competing for a single resource in the presence of an external inhibitor and with different removal rates is considered. This model was previously introduced in the case where the growth rate functions and the absorption rate of inhibitor follows the Monod kinetics and removal rates are the same as the dilution rate. In this paper, we consider the general case of monotonic functions and different removal rates. Through the three operating parameters of the system, represented by the dilution rate, the input concentrations of the substrate and the inhibitor, we give necessary and sufficient conditions for existence and stability of all equilibria. By means of operating diagrams, we describe the asymptotic behavior of the model with respect to those operating parameters. Some examples are given to illustrate the mathematical results.

The first-principles computations of density functional theory are employed to characterize the structural properties, electronic structures, and ferromagnetism induced by Cr impurities in Ca1-xCrxO compounds at concentrations x = 0. 25, 0.5, and 0.75. The dynamic stability is performed by the phonon spectra calculations. The structural parameters are computed by using Wu-Cohen generalized gradient approximation, while the electronic and magnetic properties are determined by the accurate Tran–Blaha-modified Becke–Johnson exchange potential. The crystal field, direct and indirect exchange splittings were investigated to determine the origin and stability of ferromagnetic state configuration. The Ca1-xCrxO systems have right half-metallicities, which are verified by the spin polarization of 100% and the integer values of total magnetic moments. The Ca0.75Cr0.25O, Ca0.5Cr0.5O, and Ca0.25Cr0.75O are half-metallic ferromagnetic with flip-gaps of 1.495, 0.888, and 0.218 eV, respectively. Therefore, the Ca1-xCrxO materials are suitable candidates for possible applications of spin-injection in future semiconductors spintronics.

International audience; The emergence of a new generation of applications led to the appearance of new challenges that represent improvements in current communication technologies. For this, a new network paradigm's including edge computing that allows the process of data at the edge of the network. And the 5G network slicing that represents a new generation of communication increases the capacity of mobile networks by supporting the slicing technology that allows virtual “cutting” of a telecommunications network in several slices that provide high performance in terms of bandwidth and latency. Slice allocation and placement is an important networking optimization task that still painstakingly tune heuristics to get a sufficient solution. These algorithms use data as input and outputs near-optimal solutions. Thus, we are motivated by replacing this tedious process with the recent deep reinforcement learning algorithms. In this paper, we propose three approaches for Virtual Network Functions (VNFs) slices placement in edge computing (Integer linear programming (ILP), reinforcement learning (RL), and deep reinforcement learning (DRL)). Then they are implemented and evaluated. Several scenarios are considered to study the behavior of the algorithms and to quantify the impact of network size. The results show the feasibility and efficiency of the proposed techniques in terms of server utilization, placement time, and energy consumption.

International audience; The emerging of the internet of things (IoT) led to increasing the computation resources required to satisfy a large number of requests from the connected devices, for this the Cloud Computing (CC) allows the processing of requests in the cloud to guarantee the efficiency of services for end-users. The main problem of the current CC architecture is the latency in real-time applications such as video streaming, which require a distributed architecture to support the future generation of applications. The Mobile Edge Computing (MEC) provides a fully distributed architecture where a part of processing executed in the edge of network which supports the requirements of IoT applications. In this paper, we propose to use the connected devices as on-demand virtual edge servers to provide computation services close to endusers where each submitted task is divided into a set of sub-tasks, each one can be executed by any other device which is a part of the virtual edge server according to the available resources in the selected device. In this context, we have formulated the partitioned and the offloading problem in MEC environment using linear programming techniques. Optimal Partitioned and Offloading (OPO) algorithm that allocates network, storage and computing resources to user application sub-tasks with respect to MEC constraints and user quality requirements is modeled, implemented, and evaluated. Results show the feasibility and efficiency of the proposed algorithms.

International audience; Visual analysis of human behavior is a broad field within computer vision. In this field of work, we are interested in dynamic methods in the analysis of crowd behavior which consist in detecting the abnormal entities in a group in a dense scene. These scenes are characterized by the presence of a great number of people in the camera’s field of vision. The major problem is the development of an autonomous approach for the management of a great number of anomalies which is almost impossible to carry out by human operators. We present in this paper a new approach for the detection of dynamic anomalies of very dense scenes measuring the speed of both the individuals and the whole group. The various anomalies are detected by dynamically switching between two approaches: An artificial neural network (ANN) for the management of group anomalies of people, and a DensityBased Spatial Clustering of Application with Noise (DBSCAN) in the case of entities. For greater robustness and effectiveness, we introduced two routines that serve to eliminate the shades and the management of occlusions. The two latter phases have proven that the results of the simulation are comparable to existing work.

International audience; Un-doped, Al-doped, and Sn-Al co-doped ZnO thin films have been successfully synthesized by Spray Pyrolysis method. Zinc Nitrate (Zn(NO3)2), Tin Chloride (SnCl2) and Aluminum Nitrate (Al(NO3)3) were used as starting chemicals at different compositions. Films depositions were carried out on glass substrates at 350 °C. The X-ray diffraction confirmed that the Al-Sn co-doping did not change the ZnO Hexagonal Wurtzite structure. The obtained un-doped ZnO films were highly oriented along the preferential (002) crystallographic plane while the Sn- Al co-doped ZnO films were disoriented with slight loss of crystallinity. The optical measurement showed an increase of the average transmittance from 65 % to 81 % and the band gap energy (Eg) from 3.23 to 3.30 eV. The electrical conductivity has increased with the Al-Sn co-doping concentration to reach the value of 0.335 (Ω.cm)−1.

In remote sensing, for applications as environment monitoring, change detection based on image processing is one of the most important techniques. To reach high performance various techniques of fu...

International audience; We propose to utilize rideshare taxis as infrastructure for both communication and computation. Rideshare overlays become hence Mobile Edge Nodes. End-users utilize near rideshare taxis as edge servers to receive video chunks for live video streaming. The set cover problem (SCP) is used to formulate the rideshare taxis coverage optimization inside the city. It provides the maximum number of rideshare taxis that cover end-users routes which guarantee the efficiency of communication services. Simulation results show that the proposed architecture dramatically enhances the quality of service and the overall communication performance in terms of execution time and energy consumption.

International audience; This paper attempts to investigate the free vibration of functionally graded material beams with nonuniform width based on the nonlocal elasticity theory. The theoretical formulations are established following the Euler-Bernoulli beam theory, and the governing equations of motion of the system are derived from the minimum total potential energy principle using the nonlocal elasticity theory. In addition, the Differential Quadrature Method (DQM) is applied, along with the Chebyshev-Gauss-Lobatto polynomials, in order to determine the weighting coefficient matrices. Furthermore, the effects of the nonlocal parameter, cross-section area of the functionally graded material (FGM) beam and various boundary conditions on the natural frequencies are examined. It is observed that the nonlocal parameter and boundary conditions significantly influence the natural frequencies of the functionally graded material beam cross-section. The results obtained, using the Differential Quadrature Method (DQM) under various boundary conditions, are found in good agreement with analytical and numerical results available in the literature.

International audience; The [Aliquat+][Cl−] ionic liquid (IL) has been structural and vibrationally characterized combining experimental FT-IR, FT-Raman and 1H- and 13C-NMR spectroscopies with theoretical studies based on the hybrid B3LYP/6-31G* method. The theoretical determination of structure of IL in gas phase and aqueous solution by using that level of theory shows three ionic C-H···Cl bonds, as supported by atomic Merz-Kollman (MK) charges, bond orders, natural bond orbital (NBO) and atoms in molecules (AIM) calculations. Hence, a monodentate coordination between the [Aliquat+] cation and Cl anion has been proposed for IL because only one of three ionic C-H···Cl bonds presents higher energy and lower distance. The optimized structure confirmed by NMR measurements has allowed the assignments of 237 normal vibration modes to the bands observed in the infrared and Raman spectra with the aid of scaled quantum mechanical force field (SQMFF) methodology and the normal internal coordinates. The effect of Cl in the IL is the shifting of vibration modes corresponding to the CH2 and CH3 groups, as compared with the cation. The mapped MEP surface evidence a strong concentration of charges around the chloride anion compatible with nucleophilic sites in these regions while the frontier orbital analyses suggest that IL is most reactive than the cation probably due to the low values of both global electrophilicity and nucleophilicity indexes. The thermal stability shows that [Aliquat+][Cl−] start to decompose just above 200°C. Comparisons between [Aliquat+][Cl−] and [Aliquat+][NTf2−] ILs show that the IL containing chloride is most reactive than the other one while [Aliquat+] [NTf2−] is thermally more stable than [Aliquat+][Cl−]. These results suggest that the properties of an IL containing the [Aliquat+] cation are strongly dependent of anion. In addition, the scaled force constants for the [Aliquat+][Cl−] IL are also calculated and compared with the reported for the cation. The Cl anion modifies in notable form the properties of cation.

Оптимізація електричних характеристик електронних компонентів є основною метою більшості сучасних досліджень у цій галузі. У роботі проведено експериментальне дослідження діода Шотткі. Дослідження базується на застосуванні нового підходу вимірювання, який використовує контактний метод Шотткі при металізації золота. Досліджувана структура складається з підкладки InP обраного перерізу (1 см × 1 см), товщиною порядка 350 мкм, вирізаною в кристалографічній площині (100). На цій підкладці вигравіруваний тонкий шар InN (2 нм). Ми використовували золото для двох різних значень діаметрів, розміщених один біля іншого довільним чином; великий ( = 1,366038 мм) і малий ( = 0,815575 мм). Наша методика вимірювання дозволила отримати такі електричні характеристики діода Шотткі як I-V, C-V і G-V. Вимірювання дозволили обчислити коефіцієнт ідеальності ( 1,79, 2,58), струм насичення, потенційний бар'єр ( = 0,66 еВ, еВ) і послідовний опір ( Ω, Ω) для двох різних діаметрів. Результати вимірювань, отримані на нашому діоді InN/InP Au/n типу, показують оптимізовані електричні характеристики досліджуваного діода Шотткі. Ми порівняли отримані результати для кожного контакту з результатами інших нещодавніх робіт у тієї ж галузі досліджень. Порівняння показало гарне узгодження з точки зору числових значень, а також ефективності запропонованого нами методу вимірювання. Optimization of electrical characteristics for electronic components is a main objective for the majority of recent research in this field. In this work, an experimental study of the Schottky diode is realized. This study is based on the proposal of a new measurement approach which concerns the Schottky contact technique by metallization of gold. The structure studied is composed of the InP substrate of selected section (1cm × 1cm), thickness of the order of 350 μm and cut out in the crystallographic plane (100). On this substrate, a thin layer of InN (2 nm) is engraved. We have used gold (Au) for two different values of diameters placed one next to the other in an alternative way; large ( dL = 1.366038 mm) and small ( = 0.815575 mm). Our measurement technique has allowed us to obtain the electrical characteristics of the Schottky diode I-V, C-V and G-V. These measurements allowed us to calculate the ideality factor ( 1.79, 2.58), the saturation current ( IsL = 6.717x10-4mA, Issm = 6.84x10-4mA), the potential barrier (ФBL = 0.66 eV, ФBsm = 0.64 eV) and the series resistance (RsL = 271Ω, Rssm = 261Ω) of our diode for the two diameters. The measurement results obtained on our Au/n-type InN/InP diode show the optimized electrical characteristics of the studied Schottky diode. In the logic of comparison of our work, we compared the obtained results for each contact and also the important results of other recent works for the same field of research. This comparison showed us a good agreement from the point of view of numerical values as well as the effectiveness of our proposed measurement approach.

International audience; The main objective of this work is to present a numerical modeling of mixed-mode fracture in isotropic functionally graded materials (FGMs), under mechanical and thermal loading conditions. In this paper, the displacement-based method, termed the generalized displacement correlation (GDC) method, is investigated for estimating stress intensity factor (SIF). Using the ANSYS Parametric Design Language (APDL), the continuous variations of the material properties are incorporated by specified parameters at the centroid of each element. This paper presents various numerical examples in which the accuracy of the present method is verified. Comparisons have been made between the SIFs predicted by the GDC method and the available reference solutions in the current literature. A good agreement is achieved between the results of the GDC method and the reference solutions.

International audience

International audience; This study presents an analytical approach to investigate the thermodynamic behavior of functionally graded beam resting on elastic foundations. The formulation is based on a refined deformation theory taking into consideration the stretching effect and the type of elastic foundation. The displacement field used in the present refined theory contains undetermined integral forms and involves only three unknowns to derive. The mechanical characteristics of the beam are assumed to be varied across the thickness according to a simple exponential law distribution. The beam is supposed simply supported and therefore the Navier solution is used to derive analytical solution. Verification examples demonstrate that the developed theory is very accurate in describing the response of FG beams subjected to thermodynamic loading. Numerical results are carried out to show the effects of the thermodynamic loading on the response of FG beams resting on elastic foundation.