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Effect of Titania Additive on Structural and Mechanical Properties of Alumina–Fluorapatite Composites

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Journal of Materials Science & Technology 2012年第12期28卷 1130-1136页

作者： Awatef Guidara Kamel Chaari Jamel Bouaziz Laboratoire de chimie industrielle Ecole Nationale d'Ingnieurs de SfaxBP 1173 3038 Tunisie

Mechanical properties of alumina-fluorapatite composites with different titania additive amounts （0, 0.5, 1, 1.4, 2, 3, 4 and 5 wt%） have been investigated between 1200 and 1600℃. The optimum values of densification and mechanical properties of composites have been reached with 1.4 wt% of titania after the sintering process at 1500℃ for 1 h. Thus, the rupture strength of alumina-26.52 wt% Fap-1.4 wt% TiO2 reaches 75 MPa. At higher temperature and beyond 1.4 wt% TiO2 ,the densification and mechanical properties were hindered by the formation of both intergranular porosity and secondary phase. X-ray diffraction （XRD） analysis of alumina-Fap-TiO2 composites shows the formation of aluminium titanate （Al2O3-TiO2：Al2TiO5 ）. The 27Al magic angle scanning nuclear magnetic resonance analysis of Al2O3-Fap-TiO2 composites reveals the presence of octahedral and pentahedral aluminium and novel environment relative to tetrahedral aluminium sites.

关键词： Sintering Fluorapatite Alumina Titania Composites Biomedical applications

Epitaxial Growth of Gd_(0.67)Ca_(0.33)MnO_3 Thin Films by Laser Ablation

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Journal of Rare Earths 2004年第6期22卷 739-742页

作者：马衍伟 Guilloux Viry M Barahona P Pea O Moure C Applied Superconductivity Laboratory Institute of Electrical Engineering Chinese Academy of Sciences Beijing 100080 China Chimie du Solide et Inorganique Moléculaire UMR 6511 CNRS - Université de Rennes 1 Institut de Chimie de Rennes 35042 Rennes France chimie du Solide et Inorganique Moléculaire UMR 6511 CNRS - Université de Rennes 1 Institut de Chimie de Rennes 35042 Rennes France Instituto de Ceramica y Vidrio CSIC Campus de Cantoblanco 28049 Madrid Spain

Gd_(0.67)Ca_(0.33)MnO_3(GCMO)thin films grown by laser ablation on SrTiO_3(100)(STO)substrates was studied. Films are highly crystallized, very well epitaxial and single-phased. The ordering magnetic temperature(T_c)of the films is much higher than the value of bulk samples of similar composition. It is found that the GCMO film exhibits a reversal of its magnetization at low temperature when cooled under a magnetic field. The negative magnetization is a consequence of the rapid increase(～1/T)with decreasing temperature of the magnetization of a sublattice aligned antiparallel to the local field, relative to the magnetic contribution of a second sublattice which is aligned parallel to the applied field.

关键词： pulsed laser deposition Gd_(0.67)Ca_(0.33)MnO_3 thin films magnetic properties

Adsorption properties of Rosmarinus officinalis oil as green corrosion inhibitors on C38 steel in 0.5 M H_2SO_4

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Acta Metallurgica Sinica(English Letters) 2010年第1期23卷 13-20页

作者： E.El Ouariachi J.Paolini M.Bouklah A.Elidrissi A.Bouyanzer B.Hammouti J-M.Desjobert J.Costa Laboratoire de chimie Appliqu'ee et Environnement Facult'e des SciencesUniversit'e Mohamed PremierBP71760000 OujdaMorocco UMR CNRS 6134 Laboratoire de Chimie des Produits NaturelsUniversit'e de CorseFrance

Rosmarinus officinalis essential oil obtained by hydrodistillation was tested as corrosion inhibitor of steel in 0.5 M H2SO4 using weight loss measurements, and electrochemical .polarisation methods. Results obtained indicate that the corrosion rate is reduced and R. officinalis oil adsorbs on the metal surface and then inhibits corrosion process. Its inhibition efficiency increases with oil increasing content to reach 61% at 1 g/L. Polarisation curves indicate that RO acts as a cathodic inhibitor. The inhibition efficiency of naturally oil remains slightly constant with the rise of temperature. Chemical analysis of R. officinalis essential oil was carried out using capillary GC and GC/MS. The oil composition was characterized by high amount of oxygenated monoterpene （77%） with 1,8-cineol （52.1%） as main component. Discussion of adsorption was investigated on the the isotherm adsorption of essential oil on basis of essential oil composition. Finally the steel has been also reported.

关键词： Rosmarinus officinalis oil Adsorption Corrosion Inhibition Steel 1,8-cineol

Tunable UCST thermoresponsive copolymers based on natural glycyrrhetinic acid

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Chinese Chemical Letters 2021年第1期32卷 548-552页

作者： Yiran Zhao Jingyao Ma Xia Yu Min-Hui Li Jun Hu Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China Institut de Recherche de chimie Paris Chimie ParisTechPSL Research UniversityCNRSParis 75005France

Water-soluble thermoresponsive polymers present either upper critical solution temperature(UCST) or lower critical solution tempe rature(LCST) depending on the location of their miscibility range with water at high temperatures or at low *** with LCST polymers,the water-soluble UCST polymers are still less explored until *** this work three copolymers of P(AAm-co-GAA) were synthesized by copolymerizing two acrylamide monomers,acrylamide(AAm) and acrylamide functionalized with natural glycyrrhetinic acid(GAA),using reversible addition-fragmentation chain transfer(RAFT) *** copolymers exhibited the typical UCST thermoresponsive behavior,and their phase transition temperatures could be easily tuned to around 37℃ for potential biological ***,the UCST of P(AAm-co-GAA) can be adjusted not only by the content of glycyrrhetinic acid(GA) and polymer concentrations,but also by the host-guest interactions between GA and cyclodextrins(β-and γ-CD).The suitable value of UCST and the biocompatible nature of GA and CDs may endow these copolymers with practical applications in biomedical chemistry.

关键词： Thermo-responsive polymer UCST Glycyrrhetinic acid Natural product Cyclodextrin

Comparison of reduced point charge models of proteins: Molecular Dynamics simulations of Ubiquitin

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Science China Chemistry 2014年第10期57卷 1340-1354页

作者： LEHERTE Laurence VERCAUTEREN Daniel P. Unité de chimie Physique Théorique et Structurale Laboratoire de Physico-Chimie Informatique Namur MEdicine & Drug Innovation Center (NAMEDIC) Department of Chemistry University of Namur Rue de Bruxelles 61 B-5000 Namur Belgium

Reduced point charge models of amino acids are used to model Ubiquitin （PDB： 1UBQ）. They are designed （i） from local ex- tremum positions in charge density （CD） distribution functions built from the Poisson equation applied to smoothed molecular electrostatic potential functions, or （ii） from local maximum positions in promolecular electron density distribution （ED） func- tions. Charge values are fitted versus all-atom Amber99 molecular electrostatic potentials. The program GROMACS is used to generate molecular dynamics trajectories of the protein, under various implementation schemes, solvation, and temperature conditions. Point charges that are not located on atoms are considered as virtual sites with a null mass and radius. The results illustrate that secondary structure is best preserved with the CD-based model at low temperatures and in vacuum. This indi- cates that local potential energy wells are consistent with the all-atom model. However, at room temperature, the structure is best conserved when point charges are forced to be located on atoms, due to a better description of the Coulomb l-4 energy terms. The ED-based model, generated at a lower resolution, led to the largest discrepancies versus the all-atom case. The CD-based model allows the formation of protein-water H-bonds with geometrical properties similar to the all-atom ones. Con- trarily, intra-molecular H-bonds are not well described. Structural, thermodynamical, and dynamical properties of proteins modelled with reduced point charge models are also significantly affected by the choice of the solvent force field.

关键词： molecular electrostatic potential electron density smoothing of molecular fields critical points point charge model protein Ubiquitin

PYRIDINATION OF POLY(VINYL CHLORIDE) via A HOMOLYTIC PATHWAY

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Chinese Journal of Polymer Science 2007年第3期25卷 297-302页

作者： Sad Moulay Zakia Zeffouni Laboratoire de chimie-Physique Moléculaire et Macromoléculaire Faculté des Sciences de l'Ingénieur Département de Chimie IndustrielleUniversité Sad Dahlab de BlidaRoute de SoumaB. P. 270Blida 09000Algeria

PVC was subjected to a chemical modification aiming at replacing the chlorine atoms by pyridine groups via a homolytic route. Pyridine groups were peculiarly affixed to the PVC matrix via a carbon-carbon bond rather than a carbonnitrogen one. PVC was first iodinated using the Conant-Finkelstein reaction, followed by the application of the homolytic conditions of Minisci to generate pyridinated PVC with a varying degree of substitution. The extent of substitution was not high; the reaction on 30% iodinated PVC afforded a degree of modification no greater than 3%.

关键词： Conditions of Minisci Iodinated PVC Pyridinated PVC

Adsorption recovery of Ag(Ⅰ) and Au(Ⅲ) from an electronics industry wastewater on a clay mineral composite

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International Journal of Minerals,Metallurgy and Materials 2019年第6期26卷 673-680页

作者： Youness Rakhila Abdellah Elmchaouri Allal Mestari Sophia Korili Meriem Abouri Antonio Gil UniversitéHassan II de Casablanca Facultédes Sciences et TechniquesLaboratoire de Chimie Physique et de Chimie BioorganiqueBP 146Mohammedia 20650Morocco INAMAT-Science Department Los Acebos BuildingPublic University of NavarraCampus of ArrosadiaPamplona E-31006Spain

The aim of this work is to investigate the ability of an adsorbent of a clay mineral composite to remove and recover gold and silver ions from *** composite was prepared by mixing phosphogypsum(PG),obtained from an industrial waste,and a natural clay *** materials were characterized before and after use in adsorption by several *** adsorption experiments were carried out,and the effects of the contact time and the pH and temperature of solution on the removal processes were *** optimum pH for the adsorption was found to be *** adsorption of these metal ions reached equilibrium after 2 h of *** pseudo-first-and the pseudo-second-order kinetic models,as well as the Freundlich and the Langmuir isotherm equations,were considered to describe the adsorption *** maximum adsorbed amount of 85 mg·g^-1 Ag(I)and 108.3 mg·g?1 Au(III)was *** recovery of the adsorbed gold and silver ions from the adsorbent was also *** acids appeared to be the best desorption agents to recover gold and silver *** use of aqua regia gave regeneration rates close to 95.3%and 94.3%for Ag(I)and Au(III),***,the removal of gold and silver ions from an industrial wastewater was tested in batch experiments,and percentage recoveries of 76.5%and 79.9%for Ag(I)and Au(III),respectively,were *** carry out the industrial application of the proposed methodology,an economic viability study is required.

关键词： adsorption clay composite industrial wastewater gold silver

A mini review： Shape memory polymers for biomedica applications

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Frontiers of Chemical Science and Engineering 2017年第2期11卷 143-153页

作者： Kaojin Wang Satu Strandman X. X. Zhu Departement de chimie Universite de Montreal Montreal QC H3C 3J7 Canada

Shape memory polymers （SMPs） are smart materials that can change their shape in a pre-defined manner under a stimulus. The shape memory functionality has gained considerable interest for biomedical applications, which require materials that are biocompatible and sometimes biodegradable. There is a need for SMPs that are prepared from renewable sources to be used as substitutes for conventional SMPs. In this paper, advances in SMPs based on synthetic monomers and bio-compounds are discussed. Materials designed for biomedical applica- tions are highlighted.

关键词： shape memory polymer biodegradability biocompatibility biomedical application bile acids

Investigation of structural parameters and self-aggregation of Algerian asphaltenes in organic solvents

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Petroleum Science 2015年第3期12卷 509-517页

作者： Asma Larbi Mortada Daaou Abassia Faraoun Laboratoire de Synthèse organique Physico-chimieBiomolcules et Environnement (LSPBE)Department of Industrial Organic ChemistryFaculty of ChemistryUniversity of Sciences and Technology of Oran Laboratoire de chimie Physique Macromoléculaire (LCPM) Department of ChemistryFaculty of SciencesUniversity of Oran

Elemental analysis, Fourier transform infrared （FTIR）, 1H-NMR, fluorescence spectroscopy, and surface tension methods have been used to characterize the molecular structure and the aggregation behaviors of two asphaltenic fractions derived, respectively, from an Alge- rian petroleum well and a corresponding storage tank deposit. Elemental analysis, FTIR, ~H-NMR, and fluores- cence spectroscopy were used to investigate the chemical composition and structural parameters of asphaltenes, while the surface tension method was used to measure the critical micelle concentration （CMC） in organic solvents with different solubility parameters and polarities in order to characterize the asphaltenes＇ aggregation behaviors. Results show that the unstable asphaltenes fraction extracted from the storage tank deposit possesses a higher polarity （higher heteroatoms content） and a lower aro- maticity than stable asphaltenes from the petroleum well. The CMC results indicate that asphaltenes with high polarity and low aromaticity have a high solubility in polar solvents such as nitrobenzene, whereas asphaltenes with low polarity and high aromaticity are more soluble in solvents with weak polarity, like toluene. It is concludedthat the difference of structure of asphaltene samples and polarity of solvents can lead to difference of aggregation behaviors.

关键词： Asphaltenes Algerian petroleum Structural parameters - CMC