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Characterization and Photoluminescence Properties of Alumina Nanowires Elaborated by Arc-Plasma

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Journal of Materials Science & Technology 2006年第1期22卷 127-129页

作者： C.Arnoult X.Devaux H.Rinnert M.Vergnat laboratoire de Physique des materiaux UMR CNRS 7556Ecole des MinesCS14234F54042 Nancy cedexPrance

Ultrafine powders containing alumina nanowires are synthesized by DC arc plasma from pure aluminium metal. Nanowires grow only when reactive gases are composed of nitrogen and less than ten percent of oxygen. Nanowires have the diameters ranging from 20 to 80 nm and lengths ranging from hundreds nanometers to tens of micrometers. A first assumption of the mechanism process is proposed, in which nanowires grow starting directly from the aluminium. Photoluminescence measurements show that the powders have three emission peaks around 435, 530 and 750 nm resulting from different kinds of defects such as oxygen vacancies, aluminium interstitial ions and surface defects.

关键词： Nanowires Alumina Arc plasma Photoluminescence

X-ray and DFT Crystal Structure Determination and Conformational Analysis of a Pyrethroid Compound

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Chinese Journal of Structural Chemistry 2013年第10期32卷 1544-1552页

作者： YAHIAOUI Salem CHOUAIH Abdelkader HAMZAOUI Fodil laboratoire de Structure Elaboration et Applications des Materiaux Moleculaires(SEA2M)University of Mostaganem27000 MostaganemAlgeria

The structure of （E）-N-[（E）-3-[（lR,2R）-2-（3,4-dibromo-phenyl）-l-fluro-cyclopropyl]- allylidene]-2-0-tolyl-acetamide （C21HIsONFBrz, Mr = 479.18） has been determined by X-ray single- crystal diffraction and theoretical calculations to establish the configuration, stereochemistry and a stable conformation of the molecule. The compound crystallizes in the monoclinic space group P21/c, a = 28.3452（10）, b = 4.9311（10）, c = 14.257（2） A, fl = 102.7654（10）, V = 1943.5（5） A3 and Z = 4. The structure has been refined to the final R = 0.05 for the observed structure factors with 1 〉 30（/）. Theoretical calculations in the ground state have been carried out for the compound studied using the Hartree-Fock （HF） and density functional theory （DFT）（B3LYP） with 6-31G（d,p） basis sets. The results show that the studied compound prefers the keto form. The compound involves intra- and intermolecular hydrogen bonding of C-H.-.O and C-H-..F types, which further stabilize the structure and display a trans configuration for the C=N and C=C double bonds. The calculated results show that the predicted geometry can well reproduce the structural parameters.

关键词： X-ray diffraction crystal structure insecticide

Naked Eye and Selective Detection of Copper(II) in Mixed Aqueous Media Using a Cellulose-based Support

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Chemical Research in Chinese Universities 2019年第4期35卷 598-603页

作者： FETTOUCHE Souad BOUKHRISS Aicha TAHIRI Mohamed CHERKAOUI Omar BAZI Fathallaah GMOUH Said laboratoire Recherche sur les materiaux Textile(REN4TEX) Ecole Supeneure des Induseries de Textile et de L'habillement(ESITH)CasablancaBP 7731Maroc laboratoire Hydrogeochimie et Bassin versant Faculte des Sciences Ain ChockUniversite Hassan IICasablancaB. P 5366Maroc Laboratore Chimie Analytique et Physico-chimie des materiaux Faculte des Sciences Ben M'sik Universitie Hassan II CasablancaBP 150Macro laboratoire d'lngeniene et materiaux(LIMAT) Faculte des Sciences Ben MsikUniv er site Hassan IICasablanceBP 150Maroc

A new colorimetric sensor based-azo dye for Cu^2+ detection was synthesized and characterized by FTIR and NMR spectroscopies. The results showed that the azo dye had a high selective and sensitive recognition toward Cu^2+. The solution containing the sensor changed color from pink to pale yellow with a hypsochromic shift in the presence of Cu^2+. The sensor selectivity and sensitivity toward Cu^2+ ions were investigated by colorimetry and UV-Vis spectroscopy. For practical applications, a cellulosic textile test strip for high-selectivity detection of Cu^2+ ions in aqueous solution was developed using the synthesized azo dye as chromogenic chemosensor molecule, while using a solid cellulose textile as a substrate. As a result, a spectacular color change of the test strip was observed do pending on the amount of copper ions in contact with the strip, which allows an estimation of Cu^2+ concentration by naked eye.

关键词： Copper(II) ions detection Azo dye Chromogenic chemosensor Cellulose-based probe

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

Cotunneling transport in ultra-narrow gold nanowire bundles

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Nano Research 2013年第9期6卷 644-651页

作者： Anais Loubat Walter Escoffier Lise-Marie Lacroix Guillaume Viau Reasmey Tan Julian Carrey Benedicte Warot-Fonrose Bertrand Raquet laboratoire National des Champs magnetiques Intenses CNRS-INSA-UJF-UPS UPR3228 143 avenue de Rangueil F-31400 ToulouseFrance Universite de Toulouse INSA UPS LPCNO (Laboratoire de Physique et Chimie des Nano-Objets) F-31077 Toulouse France CNRS UMR5215 LPCNO F-31077 Toulouse France Centre d'Elaboration de materiaux et d'Etudes Structurales CNRS 29 rue Jeanne Marvig F-31077 Toulouse France

We investigate the charge transport in close-packed ultra-narrow （1.5 nm diameter） gold nanowires stabilized by oleylamine ligands. We give evidence of charging effects in the weakly coupled one-dimensional （1D） nanowires, monitored by the temperature and the bias voltage. At low temperature, in the Coulomb blockade regime, the current flow reveals an original cooperative multi-hopping process between 1D-segments of Au-NWs, minimising the charging energy cost. Above the Coulomb blockade threshold voltage and at high temperature, the charge transport evolves into a sequential tunneling regime between the nearest- nanowires. Our analysis shows that the effective length of the Au-NWs inside the bundle is similar to the 1D localisation length of the electronic wave function （of the order of 120 nm _＋ 20 nm）, but almost two orders of magnitude larger than the diameter of the nanowire. This result confirms the high structural quality of the Au-NW segments.

关键词： ultra-narrow goldnanowires 1D nano-objects electronic transport variable cotunneling Coulomb blockade

Ultra-long-working-distance spectroscopy of single nanostructures with aspherical solid immersion microlenses

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Light(Science & Applications) 2020年第1期9卷 1561-1571页

作者： Aleksander Bogucki Lukasz Zinkiewicz Magdalena Grzeszczyk Wojciech Pacuski Karol Nogajewski Tomasz Kazimierczuk Aleksander Rodek Jan Suffczynski Kenji Watanabe Takashi Taniguchi Piotr Wasylczyk Marek Potemski Piotr Kossacki Faculty of Physics University of Warsawul.Pasteura 502-093 WarsawPoland National Institute for Materials Science TsukubaIbaraki 305-0044Japan laboratoire National des Champs magnetiques Intenses CNRS-UJF-UPS-INSAavenue des Martyrs 2538042 GrenobleFrance

In light science and applications,equally important roles are played by efficient light emitters/detectors and by the optical elements responsible for light extraction and *** latter should be simple,cost effective,broadband,versatile and compatible with other components of widely desired micro-optical ***,they should also operate without high-numerical-aperture ***,we demonstrate that all these requirements can be met with elliptical microlenses 3D printed on top of light ***,the microlenses we propose readily form the collected light into an ultra-low divergence beam(half-angle divergence below 1°)perfectly suited for ultra-longworking-distance optical measurements(600mm with a 1-inch collection lens),which are not accessible to date with other spectroscopic *** microlenses can be fabricated on a wide variety of samples,including semiconductor quantum dots and fragile van der Waals heterostructures made of novel two-dimensional materials,such as monolayer and few-layer transition metal dichalcogenides.

关键词： versatile latter optics

High Temperature Stability of Platinum Nanoparticles on Few-Layer Graphene Investigated by In Situ High Resolution Transmission Electron Microscopy

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Nano Research 2011年第5期4卷 511-521页

作者： Izabela Janowska Maria-Simona Moldovan Ovidiu Ersen Herve Bulou Kambiz Chizari Marc J. Ledoux Cuong Pham-Huu laboratoire des materiaux Surfaces et ProcEdEs pour la Catalyse （LMSPC UMR 7515 CNRS） 25 rue Becquerel F-67087 Strasbourg Cedex 02 France Institut de Physique et Chimie des materiaux de Strasbourg （IPCMS UMR 7504 CNRS） 23 rue du Loess F-67037 Strasbourg Cedex 08 France

Heterogeneous catalytic reactions involve the use of highly dispersed active phases such as metal, metal oxide, or metal sulphide nanoparticIes on thermally stable supports. Fluctuations of the reaction temperature during the reactions can induce sintering of the particles. The stability of such small particles represents a crucial parameter in the development of new families of catalysts with high activity in many fields. Here we report the stability of platinum nanoparticles （2-3 nm） on a few-layer graphene （FLG） surface as studied by in situ high temperature transmission electron microscopy.

关键词： Graphene platinium nanoparticles diffusion catalysis TEM annealing

Numerical Study of Greenhouse Nocturnal Heat Losses

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Journal of Thermal Science 2011年第4期20卷 377-384页

作者： F.Berroug E.K.Lakhal M.El Omari M.Faraji H.El Qarnia laboratoire d'Automatique de l'Environnement et Procédés de Transfert UniversitéCadi AyyadFacultédes Sciences Semlalia-Département de PhysiqueMarrakech-MarocAffiliéau CNRSTURAC 28 laboratoire de Physique des materiaux MicroelectroniqueAutomatique et TechniqueDepartement de PhysiquesFaculte des Sciences Ain ChockUniversite Hassan IICasablanca-Maroc

In this study we quantify and analyze different components of nocturnal losses from a heated greenhouse with the presence of vegetation for typical winter weather conditions in Marrakesh-Morocco,using a non linear model,based on the greenhouse heat and mass *** was found that 12% of the total input heat was dissipate as a sensible and latent leakage losses,66% was lost by convective exchange through air-inner *** gain of energy at the inner-cover is dissipated at the outer-cover by radiation(66%)and convection(34%).This results point toward some practical measures to reduce heat losses:increasing air tightness,using covering materials with low-emissivity in the long wave band or putting up an external thermal curtain should provide significant energy savings.

关键词： Greenhouse energy balance heat losses numerical analysis.

Numerical investigation of Ar–NH3 mixture in homogenous DBDs

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Plasma Science and Technology 2018年第3期20卷 72-77页

作者： Barkahoum LAROUCI Soumia BENDELLA Ahmed BELASRI laboratoire de Physique des Plasmas materiaux Conducteurs et leurs Applications Faculte de PhysiqueUniversite des Sciences et de la Technologie d'Oran Mohamed Boudiaf USTO-MB El M'Naoeur B.P.1505 31 000 Oran Algeria

In this paper, a study of homogenous dielectric barrier discharge Ar–NHwas made in order to investigate the electrical and the physical characteristics of homogenous discharge at atmospheric pressure. The discharge model includes the electrical module and the chemical kinetic module. The results obtained by the present model were compared with experimental work. The evolution of the plasmas voltage, the species densities, and the concentration of charged species are analyzed and discussed.

关键词： plasma simulation dielectric barrier discharge Ar-NH3 mixture