Search results for " neutron scattering"

showing 5 items of 205 documents

Micelles in Mixtures of Sodium Dodecyl Sulfate and a Bolaform Surfactant

2006

Mixtures composed of water, sodium dodecyl sulfate (SDS), and a bolaform surfactant with two aza-crown ethers as polar headgroups (termed Bola C-16) were investigated by modulating the mole ratios between the components. The two surfactants have ionic and nonionic, but ionizable, headgroups, respectively. The ionization is due to the complexation of alkali ions by the aza-crown ether unit(s). Structural, thermodynamic, and transport properties of the above mixtures were investigated. Results from surface tension, translational self-diffusion, and small angle neutron scattering ( SANS) are reported and discussed. Interactions between the two surfactants to form mixed micelles result in a com…

mixed micellesIonic bondingEtherANGLE NEUTRON-SCATTERINGMicelleanionic surfactants; mixed micelles; neutron scatteringSurface tensionSurface-Active Agentschemistry.chemical_compoundPulmonary surfactantAQUEOUS-SOLUTIONSSodium sulfateanionic surfactantsElectrochemistrySurface TensionGeneral Materials ScienceSodium dodecyl sulfateSANS surfactant mixtures micellesMicellesSpectroscopyHYDROCARBON SURFACTANTSPHASE SEPARATION MODELChromatographyneutron scatteringSodium Dodecyl SulfateSurfaces and InterfacesCondensed Matter PhysicsSmall-angle neutron scatteringchemistryChemical engineeringLangmuir
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Nanocomposites based on block copolymers and inorganic nanoparticles. Structural and thermal properties

2009

nanocomposites neutron scattering thermal properties
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Preparation of Nd:YAG Nanopowder in a Confined Environment

2007

Nanopowder of yttrium aluminum garnet (YAG, Y3Al5O12) doped with neodymium ions (Nd:YAG) was prepared in the water/cetyltrimethylammonium bromide/1-butanol/n-heptane system. Aluminum, yttrium, and neodymium nitrates were used as starting materials, and ammonia was used as a precipitating agent. Coprecipitate hydroxide precursors where thermally treated at 900 degrees C to achieve the garnet phase. The starting system with and without reactants was characterized by means of the small-angle neutron scattering technique. The system, without reactants, is constituted by a bicontinuous structure laying near the borderline with the lamellar phase region. The introduction of nitrates stabilizes th…

nanopowderswide angle x-ray scatteringAnalytical chemistrychemistry.chemical_elementMineralogyNeodymiummicroemulsionsYAG [Nd]Lamellar phasePhase (matter)transmission electron microscopyElectrochemistryGeneral Materials ScienceMicroemulsionYAG; nanopowders; syntheisi in confined environment; microemulsions; wide angle x-ray scattering; transmission electron microscopy; photoluminescence spectroscopy [Nd]Wide-angle X-ray scatteringSpectroscopySurfaces and InterfacesYttriumCondensed Matter PhysicsSmall-angle neutron scatteringchemistrysyntheisi in confined environmentphotoluminescence spectroscopyTransmission electron microscopyNdYAG microemulsion synthesis in confined environmentLangmuir
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Water Dynamics in Biological Systems investigated using Neutron Scattering Techniques

Living systems can not survive in absence of the water environments which play a fundamental role in living functions. Thus in the scienti?c community many studies were and are addressed to characterize water and its dynamics properties in biological systems. However, a clear description of water in such systems has been not reached yet. In fact, the investigations performed with di?erent techniques - those based on Nuclear Magnetic Resonance or those based on Neutron Scattering - look at di?erent di?usive motions and interactions water-biomolecules, leading controversial results and hence generating many debates between scientists. In this thesis we support the idea that two water populati…

quasi-elastic neutron scattering intracellular water water structure and dynamics bovine brain tissues cellular systems sucrose solutionsSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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Supercooled Water Confined in a Silica Xerogel: Temperature and Pressure Dependence of Boson Peak and of Mean Square Displacements

2013

A silica xerogel can be obtained from an alcoxide precursor (TMOS, tetramethylortosilcate) via the sol-gel method: TMOS hydrolysis and subsequent polycondensation yields a solid, disordered, porous SiO2 matrix (average pore dimensions ~20Å). Inside the pores water is trapped and the hydration level h=gr[H2O]/gr[SiO2] can be easily controlled. The presence and temperature dependence of the boson peak (BP) in xerogel confined supercooled water was studied with inelastic neutron scattering (spectrometer IN6 at ILL, Grenoble) in xerogel samples having h=0.4 and h=0.2. After careful subtraction of the contributions arising from the matrix and from quasi-elastic scattering, the BP contribution wa…

silica xerogel boson peak inelastic neutron scattering excess density of states LDL->HDL transition mean square displacements elastic neutron scattering protein dynamical transitionSettore FIS/07 - Fisica Applicata(Beni Culturali Ambientali Biol.e Medicin)
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