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Synthesis,structural and dielectric properties of Ho-doped SrBi_2Nb_2O_9 prepared by Co-precipitation method

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Science China Materials 2016年第11期59卷 921-926页

作者： Mohamed Afqir Amina Tachafine Didier Fasquelle Mohamed Elaatmani Jean-Claude Carru Abdelouahad Zegzouti Mohamed Daoud Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications Facultédes Sciences SemlaliaUniversitéCadi AyyadMarrakechMaroc Unitéde Dynamique et Structure des Matériaux Moléculaires Universitédu Littoral Côte d’OpaleCalaisFrance

This paper reported the synthesis of Ho-doped SBN(SrBi_(2-x)Ho_xNb_2O_9:x = 0 and 0.4) by a co-precipitation method and investigated the synthesized material with X-ray diffraction analyses,infrared spectroscopy,and electrical *** results show that the Ho-doped SBN has low loss values at higher frequencies and the flattening of dielectric constant which are very desirable in nonvolatile ferroelectric random access memory applications.

关键词： Co-precipitation XRD FTIR Dielectric properties

Prediction model for the diffusion length in silicon-based solar cells

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Journal of Semiconductors 2009年第7期30卷 3-6页

作者： Cheknane A Benouaz T Laboratoire d'etude et Dveloppement des Matriaux Semiconducteurs et Dilectrques Universit Amar Telidji de Laghouat Laboratoire de Modlisation UniversitAbou BakarBelkaid de Tlemcen Algrie

A novel approach to compute diffusion lengths in solar cells is presented. Thus, a simulation is done; it aims to give computational support to the general development of a neural networks （NNs）, which is a very powerful predictive modelling technique used to predict the diffusion length in mono-crystalline silicon solar cells. Furthermore, the computation of the diffusion length and the comparison with measurement data, using the infrared injection method, are presented and discussed.

关键词： diffusion length minority-cartier lifetime infrared injection solar cell prediction modelling

Extraction and Characterization of Aucoumea klaineana Pierre (Okoume) Extractives

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Journal of Renewable Materials 2019年第6期7卷 517-522页

作者： Engozogho Anris Starlin Peguy Bikoro Bi Athomo Arsene Vidal Marcia Denaud Louis Safou Tchiama Rodrigue Charrier Bertrand CNRS/Univ Pau&Pays Adour Institut des Sciences Analytiques et de Physico-Chimie pour l’Environnement et les Matériaux-XylomatUMR525440004Mont de MarsanFrance Laboratoire de Recherche et de Valorisation du Matériau Bois(LaReVa Bois).Ecole Normale Supérieure d’Enseignement Technique(ENSet).BP.3989 LibrevilleGabon Laboratoire des Substances Naturelles et de Synthèses Organométalliques(LASNSOM).Unitéde Recherche en Chimie(URChi).BP.941 Universitédes Sciences et Techniques de Masuku.Franceville Gabon Laboratoire Bourguignon des Matériaux et Procédé ClunyFrance Ecole Catholique d'Arts et Métiers(ECAM) 40 Montée Saint Barthéllemy69321Lyon cedex O5France-Lyon

In order to promote convenient strategies for the utilization of wood wastes from aucoumea klaineana pierre(okoume)timber industry,various chemical analysis were carried out on samples from different *** extractives content of the bark,sapwood and heartwood of okoume were *** analyses were performed and the stiasny number was *** was found that the bark was richer in fatty acid of high molecular weight while the sapwood was rich in fatty acid of low molecular *** condensed tannins content varied according to the origin and the part of the *** new findings should be useful for green okoume based tannin adhesives.

关键词： Extractibles fatty acids tannins polyphenols stiasny number TGA

Degradation of direct azo dye by Cucurbita pepo free and immobilized peroxidase

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Journal of Environmental Sciences 2013年第6期25卷 1235-1244页

作者： Nabila Boucherit Mahmoud Abouseoud Lydia Adour Université Mouloud Mammeri Laboratoire de Biomatériaux et de Phénomènes detransports Université Dr.Yahia Fares Laboratoire de Biomatériaux et de Phénomènes de Transports Université Dr.Yahia Fares Laboratoire de Génie de la Réaction Faculté de Génie Mécanique et Génie des ProcédésUniversité Houari Boumediene Laboratoire des Biotechnologies environnementales et Génie des Procédés

Enzymatic decolourization of the azo dye, Direct Yellow （DY 106） by Cucurbita pepo （courgette） peroxidase （CP） is a complex process, which is greatly affected by pH, temperature, enzyme activity and the concentrations of H202 and dye. Courgette peroxidase was extracted and its performance was evaluated by using the free-CP （FCP） and immobilized-CP （ICP） forms in the decolourization of DY106. Immobilization of peroxidase in calcium alginate beads was performed according to a strategy aiming to minimize enzyme leakage and keep its activity at a maximum value by optimizing sodium alginate content, enzyme loading and calcium chloride concentration. The initial conditions ~it which the highest DY106 decolourization yield was obtained were found at pH 2, temperature 20~C, H202 dose 1 mmol/L （FCP） and 100 mmol/L （ICP）. The highest decolourization rates were obtained for dye concentrations 50 mg/L （FCP） and 80 mg/L （ICP）. Under optimal conditions, the FCP was able to decolorize more than 87% of the dye within 2 min. While with ICP, the decolourization yield was 75% within 15 rain. The decolourization and removal of DY106 was proved by UV-Vis analysis. Fourier transform infrared （FF-IR） spectroscopy analysis was also performed on DY106 and enzymatic treatment precipitated byproduct.

关键词： Cucurbita pepo peroxidase immobilization decolourization azo dye

Fragrant Microcapsules Based onβ-Cyclodextrin for Cosmetotextile Application

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Journal of Renewable Materials 2019年第12期7卷 1347-1362页

作者： Maroua Ben Abdelkader Nedra Azizi Ayda Baffoun Yves Chevalier Mustapha Majdoub Laboratoire des Interfaces et Matériaux Avancés(LIMA) Facultédes SciencesUniversitéde Monastirbd de l’Environnement5019 MonastirTunisia Laboratoire d’Automatique de Génie des Procédés et de Génie Pharmaceutique(LAGEPP)UniversitéClaude Bernard Lyon 1UMR CNRS 500743 bd du 11 Novembre 191869622 Villeurbanne CedexFrance Unitéde Recherche Matériaux et Procédés Textiles Universitéde MonastirÉcole Nationale d’Ingénieurs de Monastirav.Ibn Eljazzar5019 MonastirTunisia

Microencapsulation of neroline inside microcapsules having a polyurethane shell based onβ-cyclodextrin(β-CD)and hexane diisocyanate was performed by interfacial *** polyol nature ofβ-CD caused tight crosslinking of microcapsules *** of neroline were characterized for their chemical composition and structure of the polyurethane shell by FTIR spectroscopy,thermogravimetric analysis,optical and electron microscopy,light scattering and electrophoresis *** content and encapsulation yield were 15%and 60%,*** microcapsules of mean diameter 29μm were slightly cationic with an isoelectric point of ***-loaded microcapsules were fixed on cotton fabric using an impregnation *** functionalized fabric showed improved resistance to washing cycles in comparison with previously reported diol-based *** microcapsules display great potential for the long-lasting release of fragrance in the framework of cosmetotextile.

关键词： Microcapsules interfacial polycondensation β-cyclodextrin neroline cosmetotextile

Geochemistry, mineral paragenesis and geothermal conditions of oreforming fluids from the Ain El Bey Cu–Fe deposit: potential occurrence of native gold and precious metal traces (North African orogenic belt, Northern Tunisia)

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Acta Geochimica 2024年第2期43卷 366-384页

作者： Rania Ben Aissa Wiem Ben Aissa Said Tlig Lassaad Ben Aissa Abdessalem Ben Haj Amara Faculty of Science of Bizerte University of Carthage7021 ZarzounaBizerteTunisia Laboratoire de Recherche Ressources Materiaux et EcosystemesUniversity of Carthage7021 ZarzounaBizerteTunisia Department of Geology University Claude Bernard Lyon 169622 VilleurbanneFrance Faculty of Science of Tunis University of Tunis-El ManarRommana1068 TunisTunisia

The Ain El Bey abandoned mine, in North-West Tunisia, fits into the geodynamic context of the European and African plate boundary. Ore deposit corresponds to veins and breccia of multiphase Cu–Fe-rich mineralization related to various hydrothermal fluid circulations. Petromineralogical studies indicate a rich mineral paragenesis with a minimum of seven mineralization phases and, at least, six pyrite generations. As is also the case for galena and native silver, native gold is observed for the first time as inclusion in quartz which opens up, thus, new perspectives for prospecting and evaluating the potential for noble metals associated with the mineralization. Scanning Electron Microscope--Energy Dispersive Spectroscopy and Transmission electron microscopy analyses show, in addition, a large incorporation of trace elements, including Ag and Au, in mineral structures such as fahlores(tetrahedrite-tennantite) and chalcopyrite ones. The mineral/mineral associations, used as geothermometers, gave estimated temperatures for the mineralizing fluids varying from 254 to 330 ℃ for phase Ⅲ, from 254 to 350 ℃ for phase Ⅳ, and from 200 to 300 ℃ for phases Ⅴ and Ⅵ. The seventh and last identified mineralization phase, marked by a deposit of native gold, reflects a drop in the mineralizing fluid’s temperature(etal research and the revaluation of the Cu–Fe ore deposit at the Ain El Bey abandoned mine, as well as at the surrounding areas fitting in the geodynamic framework of the Africa-Europe plate boundary.

关键词： Ore-formingﬂuids Mineral geochemistry Mineral geothermometers Native silver-gold Ain El Bey Ore deposit North Tunisia

Existence results for unilateral contact problem with friction of thermo-electro-elasticity

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Applied Mathematics and Mechanics(English Edition) 2015年第7期36卷 911-926页

作者： H.BENAISSA EL-H.ESSOUFI R.FAKHAR Laboratoire de Recherche en Mathématique Informatique et Sciences de l’Ingénieur (MISI) Laboratoire de Science des Matériaux des Milieux et de la Modélisation (LS3M)Université Hassan 1

This work studies a mathematical model describing the static process of contact between a piezoelectric body and a thermally-electrically conductive foundation. The behavior of the material is modeled with a thermo-electro-elastic constitutive law. The contact is described by Signorini＇s conditions and Tresca＇s friction law including the electrical and thermal conductivity conditions. A variational formulation of the model in the form of a coupled system for displacements, electric potential, and temperature is de- rived. Existence and uniqueness of the solution are proved using the results of variational inequalities and a fixed point theorem.

关键词： static frictional contozt thermo-piezoelectric material Signorini's condi-tion Tresca's friction frictional heat generation variational inequality fixed point process

Effect of the synthesis route on the structural and dielectric properties of SrBi1.8Y0.2Nb2O9 ceramics

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International Journal of Minerals,Metallurgy and Materials 2018年第11期25卷 1304-1312页

作者： Mohamed Afqir Amina Tachafine Didier Fasquelle Mohamed Elaatmani Jean-Claude Carru Abdelouahad Zegzouti Mustapha El Hammioui Laboratoire des Sciences des Matériaux Inorganiques et leurs Applications Facultédes Sciences SemlaliaUniversitéCadi AyyadMarrakech 40000Maroc Unite de Dynamique et Structure des Materiaux Moleculaires Universite du Littoral-Cote d’OpaleCalais 62100France Laboratoire de recherche sur la réactivitédes matériaux et l’optimisation des procédés Facultédes Sciences SemlaliaUniversitéCadi Ayyad 40000MarrakechMaroc

This work is devoted to the synthesis and characterization of yttrium-doped SrBi_2Nb_2O_9 ceramics prepared by three methods: solid state reaction, co-precipitation, and hydrothermal. Multiple characterizations, specifically scanning electron microscopy(SEM), X-ray powder diffraction(XRD), and Fourier transform infrared spectroscopy(FTIR), were used to validate the structural feature. The crystallite size was estimated by Scherrer's formula and the Williamson–Hall plot. The effect of the process on the band intensities of the FTIR spectra was investigated. The crystallite size and microstructure of ceramics prepared from different synthesis processes were strongly influenced by the sinterability. SEM images revealed nanograin ceramics for materials prepared by co-precipitation and hydrothermal methods and micrograin ceramics prepared by the solid state method. The synthesized compounds underwent phase transitions at 480–465°C. The dielectric and electrical properties of these Y-doped SrBi_2Nb_2O_9 ceramics appear to be dependent on the grain size.

关键词： Aurivillius,synthesis routes crystallite size microstructure dielectric

TiO_2 nanotubes as solid-phase extraction adsorbent for the determination of polycyclic aromatic hydrocarbons in environmental water samples

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Journal of Environmental Sciences 2011年第5期23卷 860-867页

作者： Bochra Bejaoui Kefi Latifa Latrous El Atrache Hafedh Kochkar Abdelhamid Ghorbel Laboratoire des Matériaux Utiles Institut National de Recherche et d'Analyse Physico-chimiqueple technologique Sidi-Thabet 2020 Tunis Tunisia Laboratoire de Chimie Analytique et Electrochimie Département de Chimie Facultédes Sciences de TunisCampus Universitaire2092 EL Manar TunisTunisia Laboratoire de Chimie des Matériaux et Catalyse Facultédes Sciences de TunisCampus Universitaire2092 EL Manar Tunis Tunisia

An analytical method based on TiO2 nanotubes solid-phase extraction （SPE） combined with gas chromatography （GC） was established for the analysis of seven polycyclic aromatic hydrocarbons （PAHs）： acenaphtylene, acenaphthene, anthracene, fluorene, phenanthrene, fluoranthene and pyrene. Factors affecting the extraction efficiency including the eluent type and its volume, adsorbent amount, sample volume, sample pH and sample flow rate were optimized. The characteristic data of analytical performance were determined to investigate the sensitivity and precision of the method. Under the optimized extraction conditions, the method showed good linearity in the range of 0.01-0.8 μg/mL, repeatability of the extraction （RSD were between 6.7% and 13.5%, n = 5） and satisfactory detection limits （0.017-0.059 μg/mL）. The developed method was successfully applied to the analysis of surface water （tap, river and dam） samples. The recoveries of PAHs spiked in environmental water samples ranged from 90% to 100%. All the results indicated the potential application of titanate nanotubes as solid-phase extraction adsorbents to pre-treat water samples.

关键词： Ti02 nanotubes hydrothermal treatment solid phase extraction gas chromatography polycyclic aromatic hydrocarbons