Search results for "surface"

showing 10 items of 9345 documents

Biphasic dimerisation of methylacrylate--immobilisation and stabilisation of cationic Pd-catalysts in ionic liquids by an ammoniumphosphine ligand.

2002

The first continuous, biphasic, Pd-catalysed dimerisation of methylacrylate is described. The biphasic system has been realised by using a tetrafluoroborate ionic liquid as catalyst medium and an ammoniumphosphine ligand to immobilise and stabilise the Pd-catalyst.

TetrafluoroborateLigandInorganic chemistryMetals and AlloysCationic polymerizationGeneral ChemistryCatalysisSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsCatalysischemistry.chemical_compoundchemistryIonic liquidMaterials ChemistryCeramics and CompositesChemical communications (Cambridge, England)
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Conformation of a chain polyelectrolyte in solution with low molecular weight salt: small angle neutron scattering measurements

1986

Small angle neutron scattering measurements have been carried out on the tetramethylammonium salt of the polystyrenesulfonic acid withDP w =310 and 1060 in water solution with tetramethylammonium chloride with ionic strength between 0.02 M and 1.0 M. The scattering curves in the scattering vector range 0.05 nm−1≤Q≤1.8nm−1 have been fitted using the form factor of a worm-like chain of finite thickness. The conformational parameters mean square radius of gyration, statistic chain element, mass per unit length and mean square radius of the cross-section have been determined experimentally and used for describing the conformation of the coils. By these molecular weights and ionic strengths, exc…

TetramethylammoniumPolymers and PlasticsScatteringIonic bondingThermodynamicsNeutron scatteringSmall-angle neutron scatteringchemistry.chemical_compoundCrystallographyColloid and Surface ChemistrychemistryIonic strengthTetramethylammonium chlorideMaterials ChemistryRadius of gyrationPhysical and Theoretical ChemistryColloid & Polymer Science
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A 2,3-dialkoxynaphthalene-based naphthocage

2019

A 2,3-dialkoxynaphthalene-based naphthocage has been synthesized. This naphthocage prefers to bind small organic cations with its low-symmetry conformation, which is in contrast to 2,6-dialkoxynaphthalene-based naphthocages. Self-sorting of these two naphthocages with two structurally similar guests tetramethylammonium and tetraethylammonium was achieved as well. peerReviewed

TetramethylammoniumTetraethylammoniumMetals and AlloyskationitGeneral ChemistryContrast (music)Medicinal chemistryCatalysisSurfaces Coatings and FilmsElectronic Optical and Magnetic Materialschemistry.chemical_compoundchemistryMaterials ChemistryCeramics and Compositessupramolekulaarinen kemia
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Ion Pair Recognition of Quaternary Ammonium and Iminium Salts by Uranyl-Salophen Compounds in Solution and in the Solid State

2007

Efficient ditopic receptors for quaternary ammonium and iminium salts have been obtained upon functionalization of the uranyl-salophen unit with conformationally flexible side arms bearing phenyl or beta-naphthyl substituents. Binding affinities in chloroform solution have been measured for a large number of quaternary salts comprising tetramethylammonium (TMA), tetrabutylammonium (TBA), acetylcholine (ACh), N-methylpyridinium (NMP), and N-methylisoquinolinium (NmiQ) cations. Recognition of the anion partner is ensured by coordination to the hard Lewis acidic uranyl center, whereas cation-pi/CH-pi interactions of the quaternary ions are established with the aromatic pendants. The role of th…

Tetramethylammoniumchemistry.chemical_classificationChloroformStereochemistryIminiumSalt (chemistry)General ChemistryCrystal structureUranylBiochemistryCatalysischemistry.chemical_compoundColloid and Surface ChemistrychemistryPolymer chemistryMoleculeAmmonium
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ChemInform Abstract: ortho-Functionalized Aryltetrazines by Direct Palladium-Catalyzed C-H Halogenation: Application to Fast Electrophilic Fluorinati…

2016

A general catalyzed direct C-H functionalization of s-tetrazines is reported. Under mild reaction conditions, N-directed ortho-C-H activation of tetrazines allows the introduction of various functional groups, thus forming carbon-heteroatom bonds: C-X (X=I, Br, Cl) and C-O. Based on this methodology, we developed electrophilic mono- and poly-ortho-fluorination of tetrazines. Microwave irradiation was optimized to afford fluorinated s-aryltetrazines, with satisfactory selectivity, within only ten minutes. This work provides an efficient and practical entry for further accessing highly substituted tetrazine derivatives (iodo, bromo, chloro, fluoro, and acetate precursors). It gives access to …

Tetrazinechemistry.chemical_compoundchemistryElectrophileElectrophilic fluorinationHalogenationchemistry.chemical_elementSurface modificationGeneral MedicineSelectivityCombinatorial chemistryCatalysisPalladiumChemInform
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Novel method for functionalising and patterning textile composites:Liquid resin print

2016

Abstract The paper reports a novel method of integrating resin into continuous textile reinforcement. The method presents a print of liquid reactive resin into textile preforms. A series of targeted injections forms a patch which upon consolidation and curing transforms into a stiff region continuously spanning through preform thickness. Enhancing the injected resin with conductive phase allows creating a pattern of patches with controlled dimensions and added functionalities. Patterned composites reveal features which are not typical for conventional composites such as fibre bridged interfaces, regular thickness variation, and gradient matrix properties. The presented study explores the ro…

Textile reinforcementA. Multifunctional compositesMaterials sciencetechnology industry and agricultureElectrically conductiveE. 3-D printingLiquid resin02 engineering and technologyBristol Composites Institute ACCIS010402 general chemistry021001 nanoscience & nanotechnology01 natural sciencesA. Carbon nanotubes and nanofibers0104 chemical sciencesMechanics of MaterialsCeramics and CompositesSurface modificationTextile compositeComposite materialB. Electrical properties0210 nano-technology/dk/atira/pure/core/keywords/composites_SRIElectrical conductorCuring (chemistry)
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Zinc oxide application in the textile industry: surface tailoring and water barrier attributes as parameters with direct implication in comfort perfo…

2013

The present study focuses on surface tailoring and water barrier attributes of zinc oxide (ZnO)-polyester composite textile materials. The surface properties, such as surface topography and roughness, composite compositions as well as thermal stability of ZnO-100% polyester textile composite materials treated through a padding process with different concentrations of ZnO dispersions as active agent in water and methanol were studied. The results show that 3% ZnO-textile composite material have enhanced water barrier properties compared with the other compositions; a fact which promises improved properties in terms of comfort. ZnO modification of polyester surfaces leads to a dramatic decre…

TextileMaterials sciencePolymers and Plasticsbusiness.industryComposite numberchemistry.chemical_elementSurface finishZincPaddingPolyesterchemistryChemical Engineering (miscellaneous)Thermal stabilityWettingComposite materialbusinessTextile Research Journal
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Cost-driven framework for progressive compression of textured meshes

2019

International audience; Recent advances in digitization of geometry and radiometry generate in routine massive amounts of surface meshes with texture or color attributes. This large amount of data can be compressed using a progressive approach which provides at decoding low complexity levels of details (LoDs) that are continuously refined until retrieving the original model. The goal of such a progressive mesh compression algorithm is to improve the overall quality of the transmission for the user, by optimizing the rate-distortion trade-off. In this paper, we introduce a novel meaningful measure for the cost of a progressive transmission of a textured mesh by observing that the rate-distor…

Texture atlasDecimationadaptive quantizationmultiplexingComputer scienceGeometry compressionComputingMethodologies_IMAGEPROCESSINGANDCOMPUTERVISIONInversesurface meshes02 engineering and technologyData_CODINGANDINFORMATIONTHEORYtexturesprogressive vs single-rate[INFO.INFO-CG]Computer Science [cs]/Computational Geometry [cs.CG]MultiplexingCCS CONCEPTS • Computing methodologies → Computer graphics020204 information systems0202 electrical engineering electronic engineering information engineering020201 artificial intelligence & image processingPolygon meshQuantization (image processing)AlgorithmDecoding methodsData compressionComputingMethodologies_COMPUTERGRAPHICS
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Rapid and eco-friendly synthesis of graphene oxide-silica nanohybrids

2014

The increasing interest in Graphene oxide (GO) is due to many issues: the presence of both sp2-conjugated atoms and oxygen-containing functional groups provides a strong hydrophilicity and the possibility to further functionalize it with other molecules (i.e. π-π interactions covalent attachment etc.) [1]. Furthermore since the GO is biocompatible and noncytotoxic many studies have been recently focused on the development of GO-based nanodevices for bioimaging DNA detection drug delivery. Due to their low cytotoxicity and large internal surface area silica nanoparticles have been taken into account as promising material for biolabeling and drug loading/delivery. Particular consideration has recently been demonstrated for GO-silica composites because of the potentialities for electrical applications their chemical inertia and stability toward ions exposure. The possibility to combine the extraordinary properties of GO and silica offers several advantages for the realization of nanoprobes for biological applications and of biosensor [12]. The strategy for the fabrication of GO-nanosilica nanohybrids can be schematized as follows: (i) synthesis of GO by oxidizing graphite powder with the method described by Marcano et al. [3] (ii) Preparation of oxygen-loaded silica nanoparticles by thermal treatments in controlled atmosphere in order to induce high NIR emission at 1272 nm from high purity silica nanoparticles. (iii) preparation of GrO-silica nanohybrid films via rapid solvent casting in water. The nanohybrids were tested by XPS FTIR Raman analysis UV photoluminescence analysis TGA Zeta potential measurements electrical tests AFM and SEM. Several nanohybrids were prepared by combining two different typologies of GO and two different samples of silica.
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L'intonaco Li Vigni nell'architettura del XX secolo a Palermo. Nuove conoscenze e applicazioni diagnostiche per la manutenzione

2013

Il saggio presenta lo studio degli intonaci formulati per imitare le pietre e i marmi naturali che si diffondono in Sicilia all’inizio del XX secolo ed evidenzia che le prime applicazioni e la diffusione delle nuove malte, anche nel resto dell’Italia, risentono delle sperimentazioni condotte in tutta l’Europa. Il contributo riassume i risultati di una rigorosa e capillare ricognizione tra i brevetti conservati presso l’Archivio Centrale dello Stato a Roma inerenti alle malte per il confezionamento dell’intonaco a “finta pietra”, ne analizza i contenuti in modo critico e pone in risalto i contatti culturali con le sperimentazioni dei materiali in atto nell’ambito dei grandi cantieri di resta…

The paper presents the study of the plaster formulated to imitate the natural stones and marbles that are popular in Sicily in the early twentieth century and points out that the first applications and the dissemination of new mortars also in the rest of Italy feels the influence of the experiments conducted throughout Europe . The contribution summarizes the results of a rigorous and thorough reconnaissance of patents kept in the Archivio Centrale dello Stato in Rome relating to mortars for plastering an artificial stone critically analyzes the content and emphasizes cultural contacts with the experiments on large-scale restoration projects in Italy and France in the late nineteenth century. The analysis of the architectural surfaces is developed with instrumental tests: the levels of adhesion of finishing surface are characterized in particular through a campaign of thermographic investigations and diagnosis is drawn to show that the consolidation of the layers and reintegration are interventions to be introduced ​​within the restoration project and maintenance program.Settore ICAR/19 - Restauro
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