Search results for "Organic Chemical"

showing 10 items of 733 documents

Surprising solvent-induced structural rearrangements in large [N⋯I+⋯N] halogen-bonded supramolecular capsules

2018

Coordinative halogen bonds have recently gained interest for the assembly of supramolecular capsules. Ion mobility-mass spectrometry and theoretical calculations now reveal the well-defined gas-phase structures of dimeric and hexameric [N...I+...N] halogen-bonded capsules with counterions located inside their cavities as guests. The solution reactivity of the large hexameric capsule shows the intriguing solvent-dependent equilibrium between the hexamer and an unprecedented pentameric [N...I+...N] halogen-bonded capsule, when the solvent is changed from chloroform to dichloromethane. The intrinsic flexibility of the cavitands enables this novel structure to adopt a pseudo-trigonal bipyramida…

inorganic chemicalsSupramolecular chemistryspectrometry studyRandom hexamer010402 general chemistry01 natural scienceshalogen-bonded supramolecular capsuleschemistry.chemical_compoundPyridinesupramolekulaarinen kemiaion mobility-massReactivity (chemistry)ta116chemistry.chemical_classification010405 organic chemistryChemistryGeneral Chemistry5400104 chemical sciencesSolventBipyramidCrystallographyspektrometriaHalogenchemical scienceCounterion500 Naturwissenschaften und Mathematik::540 Chemie::540 Chemie und zugeordnete Wissenschaften
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A surface EXAFS study of thin nickel deposits on (110) TiO2 surfaces

1997

Abstract The first stages of nickel deposition on a clean (110) TiO 2 surface were studied using surface extended X-ray absorption fine structure (EXAFS). Experiments were performed on two kinds of nickel deposits, one of 0.8 equivalent monolayers and another of 1.6 equivalent monolayers. Depositions were performed on well characterized TiO 2 (110)-p(1 × 1) surfaces. The correlation of Auger experiments with EXAFS results showed that no islands were present on the surface; only two-dimensional growth of nickel was observed. Moreover, it was shown, in the case of the thinner deposit, that a model with nickel atoms forming chains in the channels determined by oxygen atoms on the surface is co…

inorganic chemicalsSurface (mathematics)Extended X-ray absorption fine structureChemistryMetals and AlloysAnalytical chemistryNickel depositionchemistry.chemical_elementSurfaces and InterfacesSurfaces Coatings and FilmsElectronic Optical and Magnetic MaterialsAugerCrystallographyNickelOxygen atomMonolayerMaterials ChemistryAbsorption (chemistry)Thin Solid Films
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The phase coexistence method to obtain surface free energies and nucleation barriers: a brief review

2018

A recently developed method where one analyses the finite size effects associated with liquid–solid phase equilibria including vapour–crystal coexistence is briefly reviewed. It is shown that the e...

inorganic chemicalsSurface (mathematics)Materials scienceBiophysicsNucleation010402 general chemistryCondensed Matter Physics01 natural sciences0104 chemical scienceslaw.inventionColloidChemical physicslawPhase (matter)biological sciences0103 physical sciencesFree energiesPhysical and Theoretical ChemistryCrystallization010306 general physicsMolecular BiologyMolecular Physics
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Modeling of surface vs. bulk ionic conductivity in fixed charge membranes

2003

A two-region model for describing the conductivity of porous fixed charge membranes is proposed. In the surface region, the conductivity is due to the mobile positive ions (counterions) around the negative fixed charges. In the pore center region, the conductive properties resemble those of the external electrolyte solution because the fixed charges are assumed to be effectively neutralized by the counterions in the surface region. Activation energies and surface diffusion coefficients are estimated by assuming that the counterion jump from a fixed charge group is the rate limiting process for surface transport. The barrier energy for this jump is calculated using a simple electrostatic mod…

inorganic chemicalsSurface diffusionchemistry.chemical_classificationPhysics::Biological PhysicsChemistryAnalytical chemistryGeneral Physics and AstronomyThermodynamicsElectrolyteConductivityIonSurface conductivityMembraneIonic conductivityPhysical and Theoretical ChemistryCounterionPhys. Chem. Chem. Phys.
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Highly Active Co3O4-Based Catalysts for Total Oxidation of Light C1–C3 Alkanes Prepared by a Simple Soft Chemistry Method: Effect of the Heat-T…

2021

9 figures, 2 tables.

inorganic chemicalsTechnologyInorganic chemistryTotal oxidationcobalt oxidechemistry.chemical_elementalkane oxidationpropaneHeterogeneous catalysissurface oxygen vacanciesMethaneArticleCatalysischemistry.chemical_compoundPropaneAlkane oxidationSurface oxygen vacanciesPropanetotal oxidationvolatile organic compoundsGeneral Materials ScienceReactivity (chemistry)Volatile organic compoundsCobalt oxideAlkanechemistry.chemical_classificationHeterogeneous catalysisEthaneMicroscopyQC120-168.85methaneTQH201-278.5ethaneEngineering (General). Civil engineering (General)TK1-9971heterogeneous catalysischemistryDescriptive and experimental mechanicsMixed oxideElectrical engineering. Electronics. Nuclear engineeringTA1-2040cobalt oxide; total oxidation; alkane oxidation; heterogeneous catalysis; volatile organic compounds; propane; ethane; methane; surface oxygen vacanciesCobaltMethaneMaterials; Volume 14; Issue 23; Pages: 7120
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Novel organo-modifier for thermally-stable polymer-layered silicate nanocomposites

2015

A new novel approach for the stabilisation of polymer-clay nanocomposites has been investigated based on reacting chemically an antioxidant function, a hindered phenol moiety, with an organic modifier based on a quaternary ammonium salt. The chemically linked antioxidant-containing organic modifier (AO-OM) was then introduced into natural montmorillonite (MMt) through a cation-exchange reaction resulting in antioxidant-containing organo-modified clay (AO-OM-MMt). The new antioxidant-containing modified clay, along with other organo-modified clays having a similar organo-modifier but without the reacted antioxidant, were characterised by spectroscopic, thermogravimetric and x-ray diffraction…

inorganic chemicalsThermogravimetric analysisMaterials sciencePolymers and PlasticsPolymer-clay nanocompositeSalt (chemistry)complex mixtureschemistry.chemical_compoundPolymer chemistryMaterials ChemistryMoietyMechanics of MaterialAntioxidant-containing organomodifierchemistry.chemical_classificationMaterials Chemistry2506 Metals and AlloyNanocompositePolymers and PlasticModified montmorillonitePolymerCondensed Matter PhysicsExfoliation jointPA11MontmorilloniteSettore ING-IND/22 - Scienza E Tecnologia Dei MaterialichemistryChemical engineeringMechanics of MaterialsDispersion (chemistry)
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"Table 1" of "Few neutron removal from U-238 at relativistic energies"

1997

Uranium fragmentation.

inorganic chemicalsU238 CU --> U236 XU238 CU --> U235 XU238 CU --> U234 XCross Sectioncomplex mixturesU238 CU --> U237 XNUCLEUS NUCLEUS --> U234 XInclusiveNUCLEUS NUCLEUS --> U233 XNUCLEUS NUCLEUS --> U237 XNUCLEUS NUCLEUS --> U236 XNUCLEUS NUCLEUS --> U235 XU238 PB --> U235 XU238 PB --> U236 XU238 PB --> U233 XU238 PB --> U234 XIntegrated Cross Sectiontechnology industry and agricultureU238 AL --> U236 XSIGU238 AL --> U237 XU238 PB --> U237 XU238 AL --> U233 XU238 AL --> U234 XU238 AL --> U235 X
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"Table 2" of "Few neutron removal from U-238 at relativistic energies"

1997

Uranium fragmentation.

inorganic chemicalsU238 CU --> U236 XU238 PB --> U235 XU238 CU --> U235 XU238 PB --> U236 XU238 CU --> U234 XU238 PB --> U234 XIntegrated Cross Sectiontechnology industry and agricultureCross SectionU238 AL --> U236 XSIGcomplex mixturesU238 AL --> U237 XU238 PB --> U237 XU238 CU --> U237 XNUCLEUS NUCLEUS --> U234 XInclusiveU238 AL --> U234 XU238 AL --> U235 XNUCLEUS NUCLEUS --> U237 XNUCLEUS NUCLEUS --> U236 XNUCLEUS NUCLEUS --> U235 X
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Molecular basis of early epithelial response to streptococcal exotoxin: role of STIM1 and Orai1 proteins

2011

Streptolysin O (SLO) is a cholesterol-dependent cytolysin (CDC) from Streptococcus pyogenes. SLO induces diverse types of Ca(2+) signalling in host cells which play a key role in membrane repair and cell fate determination. The mechanisms behind SLO-induced Ca(2+) signalling remain poorly understood. Here, we show that in NCI-H441 cells, wild-type SLO as well as non-pore-forming mutant induces long-lasting intracellular Ca(2+) oscillations via IP(3) -mediated depletion of intracellular stores and activation of store-operated Ca(2+) (SOC) entry. SLO-induced activation of SOC entry was confirmed by Ca(2+) add-back experiments, pharmacologically and by overexpression as well as silencing of ST…

inorganic chemicalsVoltage-dependent calcium channelORAI1ImmunologyBiologyMicrobiologyCell biologyCell membranemedicine.anatomical_structureMembrane proteinVirologymedicineStreptolysinsense organsCytolysinIntracellularCalcium signalingCellular Microbiology
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Sorption of uranium(VI) onto ferric oxides in sulfate-rich acid waters.

2003

The mechanisms of the uranium(VI) sorption on schwertmannite and goethite in acid sulfate-rich solutions were studied by Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy. The samples were prepared under N2 atmosphere and initial uranium(VI) concentrations of 1 x 10(-5) (pH 6.5) to 5 x 10(-5) M (pH 4.2). The ionic strength was adjusted using 0.01 M Na2SO4 or 0.01 M NaClO4, respectively. The EXAFS structural parameters for uranium(VI) sorbed on goethite in sulfate-rich, acid and near-neutral solutions indicate that uranium(VI) forms an inner-sphere, mononuclear, bidentate surface complex. This complex is characterized by a uranium-ferric-iron distance of approximately 3.45 A. Ura…

inorganic chemicalsWater Pollutants RadioactiveGoethiteschwertmanniteInorganic chemistrychemistry.chemical_elementcomplex mixturesFerric Compoundsuraniumchemistry.chemical_compoundPerchlorateAdsorptionmedicinegoethiteEnvironmental ChemistrySulfatesorptionSulfatesSchwertmannitetechnology industry and agricultureSorptionGeneral ChemistryUraniumEXAFSchemistryvisual_artvisual_art.visual_art_mediumFerricUraniumAdsorptionacid mine drainagemedicine.drugEnvironmental MonitoringEnvironmental sciencetechnology
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