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Lateral ring compression test applied to a small caliber steel jacket:Identification of a constitutive model

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Defence Technology（防务技术） 2024年第6期36卷 133-148页

作者： Yann Coget Yael Demarty Christophe Czarnota Anthony Bracq Jean-Sebastien Brest Alexis Rusinek French-German Research Institute of Saint-Louis 5 Rue Du General Cassagnou68300 Saint-LouisFrance laboratoire d'Etude des Microstructures et de Mecanique des materiaux(LEM3) CNRSUniversite de LorraineArts&Metiers ParisTechF-57000 MetzFrance

The evolution of threats and scenarios requires continuous performance improvements of ballistic protections for armed *** a modeling point of view,it is necessary to use sufficiently precise material behavior models to accurately describe the phenomena observed during the impact of a projectile on a protective *** this context,the goal of this paper is to characterize the behavior of a small caliber steel jacket by combining experimental and numerical *** experimental method is based on the lateral compression of ring specimens directly machined from the thin and small *** speeds and temperatures are considered in a quasi-static regime in order to reveal the strain rate and temperature dependencies of the tested *** Finite Element Updating Method(FEMU)is *** results are coupled with an inverse optimization method and a finite element numerical model in order to determine the parameters of a constitutive model representative of the jacket *** of the present model are verified against experimental results and a parametric study as well as a discussion on the identified material parameters are *** results indicate that the strain hardening parameter can be neglected and the behavior of the thin steel jacket can be described by a modeling without strain hardening sensitivity.

关键词： Full metal jacket ammunition Lateral ring compression Inverse identification Numerical simulation

Electrodeposition and characterization of Cu2O thin films using sodium thiosulfate as an additive for photovoltaic solar cells

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Chinese Journal of Chemical Engineering 2018年第2期26卷 421-427页

作者： Hassiba Rahal Rafiaa Kihal Abed Mohamed Affoune Samia Rahal laboratoire d'Analyses lndustrielles et Genie des materiaux Departement de Genie des ProcedesFaculte des Sciences et de la TechnologieUniversite 8 Mai 1945 GuelmaBP 401 Cuelma 24000Algeria Universite 20 Aout 1955 Skikda BP 26Route El-Hadaiek21000Algeria Universite Abbes Laghrour Khenchela BP 1252Rue de BatnaKhenchela 40004Algeria laboratoire d'Etude des Surfaces et Interfaces de la Matiere Solide LESIMS Departement de PhysiqueFaculte des SciencesBadji Mokhtar UniversiteAnnabaAlgeria

Cuprous oxide （Cu2O） thin films have been grown by electrodeposition technique onto ITO-coated glass substrates from aqueous copper acetate solutions with addition of sodium thiosulfate at 60 ℃ The effects of sodium thiosulfate on the electrochemical deposition of Cu2O films were investigated by cyclic voltammetry and chronoamperometry techniques. Deposited films were obtained at - 0.58 V vs. SCE and characterized by X-ray diffraction （XRD）, Fourier transform infrared spectroscopy （FrIR）, scanning electron microscopy （SEM）, and optical, photoelectrochemical and electrical measurements. X-ray diffraction results indicated that the synthesized Cu2O films had a pure cubic phase with a marked preferential orientation peak along （200） plane and with lattice constants a = b = c = 0.425 rim. FFIR results confirmed the presence of Cu2O films at peak 634 cm 1. SEM images of Cu2O films showed a better compactness and spherical-shaped composition. Optical properties of Cu2O films reveal a high optical transmission （〉80%） and high absorption coefficient （α 〉 104 cm- 1 ） in visiblelight region. The optical energy band gap was found to be 2.103 eV. Photoelectrochemical measurements indicated that Cu2O films had n-type semiconductor conduction, which confirmed by Hall Effect measurements. Electrical properties of Cu2O films showed a low electrical resistivity of 61.30 Ω. cm-1, carrier concentration of-4.94×1015cm -3andmobility of20.61cm2.V 1,*** Cu2O thin films with suitable properties are promising semiconductor material for fabrication of photovoltaic solar cells,

关键词： Electrodeposition Cuprous oxide Thin films Semiconductor Cyclic voltammetry Photoelectrochemical measurements

Numerical modeling of centrifuge cyclic lateral pile load experiments

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Earthquake Engineering and Engineering Vibration 2009年第1期8卷 61-76页

作者： Nikos Gerolymos Sandra Escoffier George Gazetas Jacques Garnier Civil Engineering National Technical UniversityAthens Greece laboratoire Central des Ponts et Chaussées Nantes France Lecturer laboratoire Central des Ponts et Chaussées Nantes France

To gain insight into the inelastic behavior of piles, the response of a vertical pile embedded in dry sand and subjected to cyclic lateral loading was studied experimentally in centrifuge tests conducted in laboratoire Central des Ponts et Chaussees. Three types of cyclic loading were applied, two asymmetric and one symmetric with respect to the unloaded pile. An approximately square-root variation of soil stiffness with depth was obtained from indirect in-flight density measurements, laboratory tests on reconstituted samples, and well-established empirical correlations. The tests were simulated using a cyclic nonlinear Winkler spring model, which describes the full range of inelastic phenomena, including separation and re-attachment of the pile from and to the soil. The model consists of three mathematical expressions capable of reproducing a wide variety of monotonic and cyclic experimentalp-y curves. The physical meaning of key model parameters is graphically explained and related to soil behavior. Comparisons with the centrifuge test results demonstrate the general validity of the model and its ability to capture several features of pile-soil interaction, including： soil plastification at an early stage of loading, ＂pinching＂ behavior due to the formation of a relaxation zone around the upper part of the pile, and stiffness and strength changes due to cyclic loading. A comparison of the p-y curves derived from the test results and the proposed model, as well as those from the classical curves of Reese et al. （1974） for sand, is also presented.

关键词： centrifuge test Winkler model p-y curves cyclic loading pile-soil separation/gapping nonlinear response experimental validation

Structural and Electronic Properties of Bixo<sub>3</sub>(X = Mn, Fe, Cr)

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Journal of Modern Physics 2011年第7期2卷 642-650页

作者： Djillali Bensaid Nour-Eddine Benkhettou Ali Kourdassi laboratoire des materiaux Magnetiques Faculty of Sciences University of Sidi Bel Abbes

The candidate multiferroic BiCrO3 and its chemical neighbors BiMnO3 and BiFeO3 are known to be ferromagnetic and ferroelectric respectively. With structural distortions driven by the strongly polarizable Bi ions, we present results of the first-principles density functional calculations using the (FP-LMTO) method with the spin-orbit coupling for those materials in the pseudo-cubic perovskite phase. The results showed that the valence bands in these compounds are formed by the 6p orbitals of bismuth and 3d orbital’s of the transition metals. Our results indicate that these materials have metallic behavior for spin-up polarization but being a clear tandance for semiconductor spin-down BiMnO3.

关键词： Multiferroics Perovskite Density Functional Theory ABO3 Oxide Perovskites

Numerical Study of Natural Convection in an Inclined Porous Cavity

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Fluid Dynamics & Materials Processing 2022年第5期18卷 1389-1397页

作者： Saad Adjal Sabiha Aklouche-Benouaguef Belkacem Zeghmati laboratoire des Transports Polyphasiques et Milieux Poreux LTPMPALGER16111ALGERIE laboratoire des Mathématiques et Physique des Systèmes LAMPSPerpignan66860France

Two-dimensional transient laminar natural convection in a square cavity containing a porous medium and inclined at an angle of 30°is investigated *** vertical walls are differentially heated,and the horizontal walls are *** effect of Rayleigh number on heat transfer and on the road to chaos is *** natural heat transfer and the Darcy Brinkman equations are solved by using a finite volume method and a Tri Diagonal Matrix Algorithm(TDMA).The results are obtained for a porosity equal to 0.45,a Darcy number and a Prandtl respectively equal to 10^(-3)and 0.71;they are analyzed in terms of streamlines,isotherms,phase portrait,attractors,and spectra amplitude as a function of the Rayleigh *** is found that,as Rayleigh number increases,the natural convection changes from a steady state to a time-periodic state and finally to a chaotic condition.

关键词： Natural convection porous medium finite volumes chaos attractors

Pyrolysis of olive residue/low density polyethylene mixture：Part Ⅰ Thermogravimetric kinetics

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燃料化学学报 2008年第6期36卷 672-678页

作者： ABOULKAS A E1 HARFI K El BOUADILI A laboratoire de Recherche sur la Reactivites des materiaux et l Optimisation des Procedes ＂REMATOP＂ Departement de chimie Faculte des Sciences Semlalia Universite Cadi Ayyad BP 2390 40001 Marrakech Maroc Departement de chimie Faculte polydisciplinaire de Beni-Mellal Universite Sultan Moulay Slimane BP 592 23000 Beni-Mellal Maroc laboratoire de Chimie Organique et Analytique Departement de chimie Faculte des Sciences et Techniques de Beni-Mellal Universite Sultan Moulay Slimane BP 523 23000 Beni-Mellal Maroc

This paper demonstrates the thermal pyrolysis of olive residue,low density polyethylene(LDPE) and olive residue/LDPE mixture in an inert atmosphere of N2 using thermogravimetric analysis(TGA).Measurements were carried out in the temperature range 300K^973K at heating rates of 2K/min,10K/min,20K/min and 50K/*** on the results obtained,three temperature regimes were selected for studying the non-isothermal kinetics of olive residue/LDPE *** first two were dominated by the olive residue pyrolysis,while the third was linked to the LDPE pyrolysis,which occurred at much higher *** between the experimental and calculated TG/DTG profiles were considered as a measurement of the extent of interactions occurring on *** maximum degradation temperatures of each component in the mixture were higher than those the individual components;thus an increase in thermal stability was *** kinetic parameters associated with thermal degradation were determined using Friedman isoconversional method.

关键词：高温分解反应低密度聚乙烯动力学 LDPE

Effect of Water Quality on Heavy Metal Redistribution and Mobility in Polluted Agricultural Soils in a Semi-Arid Region

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Pedosphere 2019年第6期29卷 730-739页

作者： Rim AZOUZI Abdelkrim CHAREF Lamia AYED Samia KHADHAR laboratoire Géoressources Centre des Recherches et Technologies des EauxSoliman 8020(Tunisia) laboratoire d’Analyse Traitement et Valorisation des Polluants de l’Environnement et des ProduitsFacultéde PharmacieRue AvicenneMonastir 5000(Tunisia)

Mornag Plain is a coastal area of the Mediterranean basin, which has undergone an agricultural industrial boom. The aim of this study was to investigate the different water qualities used for irrigation on heavy metal mobility in these polluted agricultural soils. The geo-accumulation indices for heavy metals (Ni, Cr, Pb, Cd, Cu, and Zn) revealed that industrial activities and used treated wastewater (TWW) contributed to soil pollution, and water irrigation always decreased this contamination. After long-term use of different water types, high perturbation of heavy metal redistribution has occurred. Groundwater use altered all heavy metal redistributions in the irrigated soil among various soil-solid and soil-solution fractions, as compared to the unirrigated soil. Slight acid water use transferred some metals from different solid phase components into water-soluble and exchangeable fractions. However, TWW use transformed some Ni, Cr, Cd, Cu, and Zn from water-soluble and exchangeable fractions to less labile fractions, particularly into organically bound fractions. Reuse of conventional water within the same soil decreased the whole soil redistribution index values, indicating tendency to return to the pattern of distribution of groundwater-irrigated soil.

关键词： Exchangeable fraction Geo-accumulation index Labile fraction Mobility factor Organically bound fraction Redistribution index Treated wastewater Water-soluble fraction

Energy Filtering and Coaxial Detection of the Backscattered Electrons in Scanning Electron Microscope

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Chinese Physics Letters 2000年第9期17卷 637-639页

作者： JIANG Chang-Zhong P.Morin N.Rosenberg Department of Physics Wuhan UniversityWuhan 430072 Departement de Physique des materiaux Universite Claude Bernard Lyon I69622 Villeurbanne CedexFrance

A new detection system in scanning electron microscope,which filters in energy and detects the backscattered electrons close to the microscope axis,is *** technique ameliorates the dependence of the *** tering coefficient on atomic number,and suppresses effectively the relief contrast at the same *** this new method is very suitable to the composition analysis.

关键词： Electron scattered system

Surface morphology and electrochemical characterization of electrodeposited Ni-Mo nanocomposites as cathodes for hydrogen evolution

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Chinese Physics B 2015年第10期24卷 559-563页

作者： Elhachmi Guettaf Temam Hachemi Ben Temam Said Benramache laboratoire de Physique des Couches Minces et Applications Université de Biskra

In this work, we study the influences of current density on surface morphology and electrochemical characterization of electrodeposited Ni-Mo. The Ni-Mo composite coatings are deposited on pretreated copper substrates by electrolytic deposition. The Ni-Mo solution is taken from nickel sulfate fluid and ammonium heptamolybdate with 10 g/l. The Ni-Mo composite coatings are deposited at a temperature of 303 K with an applied current density of j dep= 10 A/dm2-30 A/*** find that the corrosion resistance is improved by incorporating Mo particles into Ni matrix in 0.6-M Na Cl solution. From the potentiodynamic polarization curve of electrodeposited Ni-Mo it is confirmed that the corrosion resistance decreases with increasing applied current density. The x-ray diffraction（XRD） analyses of Ni-Mo coatings indicate three phases of Mo Ni4, Mo1.24Ni0.76, and Ni3 Mo phases crystallites of nickel and molybdenum. The scanning electronic microscopy（SEM） tests indicate that Ni-Mo coatings present cracks and pores.

关键词： Ni-Mo electrolytic deposition corrosion resistance potentiodynamic polarization plating current density