Search results for " DISPERSIONS"

showing 5 items of 5 documents

Ab initio studies on the lattice thermal conductivity of silicon clathrate frameworks II and VIII

2016

The lattice thermal conductivities of silicon clathrate frameworks II and VIII are investigated by using ab initio lattice dynamics and iterative solution of the linearized Boltzmann transport equation(BTE) for phonons. Within the temperature range 100-350 K, the clathrate structures II and VIII were found to have lower lattice thermal conductivity values than silicon diamond structure (d-Si) by factors of 1/2 and 1/5, respectively. The main reason for the lower lattice thermal conductivity of the clathrate structure II in comparison to d-Si was found to be the harmonic phonon spectra, while in the case of the clathrate structure VIII, the difference is mainly due to the harmonic phonon spe…

Materials scienceSiliconPhononClathrate hydrateAb initioSOLIDSchemistry.chemical_elementFOS: Physical sciences02 engineering and technology01 natural sciencesSEMICONDUCTORSLOW TEMPERATURESCondensed Matter::Materials Sciencesilicon clathrate frameworks0103 physical sciencesEQUATIONDiamond cubicSIPHONON DISPERSIONS010306 general physicsta116Condensed Matter - Materials ScienceCondensed matter physicsta114CRYSTALAnharmonicitylattice thermal conductivityMaterials Science (cond-mat.mtrl-sci)Atmospheric temperature range021001 nanoscience & nanotechnologyBoltzmann equationGENERALIZED GRADIENT APPROXIMATIONMODELchemistry0210 nano-technology
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Highly untangled multiwalled carbon nanotube@polyhedral oligomeric silsesquioxane ionic hybrids: Synthesis, characterization and nonlinear optical pr…

2015

Abstract Highly de-bundled multiwalled carbon nanotube (MWCNT) polymer nanohybrids were obtained via ionic assembling of a novel POSS-polyimidazolium-ionic liquid (POSS = polyhedral oligomeric silsesquioxanes) with oxidized MWCNTs. The synthesis, accomplished by a simple bilayer chloroform/water metathetical reaction process, was promoted by the high surfactant properties of POSS-imidazolium-polyionic liquid, which assisted the effective de-bundling, dispersion and purification of the as prepared POSS@MWCNT polymers in organic media, via a surface coating mechanism. The presence of remarkably intense radial breathing modes (RBMs) in Raman spectra, both in solution and as solid, corroborates…

NanotubeMaterials scienceDISPERSIONSGRAPHITEIonic bondingPOLY(IONIC LIQUID)S AMORPHOUS-CARBON FUNCTIONALIZATION POLYMER MATRIX OCTASILSESQUIOXANES DISPERSIONS DERIVATIVES GRAPHITE SYSTEMSchemistry.chemical_compoundsymbols.namesakeAMORPHOUS-CARBONSYSTEMSPolymer chemistryGeneral Materials Sciencechemistry.chemical_classificationOCTASILSESQUIOXANESDERIVATIVESBilayerChemistry (all)POLYMERGeneral ChemistryPolymerSilsesquioxaneSurface coatingchemistryChemical engineeringPOLY(IONIC LIQUID)SIonic liquidsymbolsFUNCTIONALIZATIONRaman spectroscopyMATRIX
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Configurational entropy of microemulsions : The fundamental length scale

1993

Phenomenological models have been quite successful in characterizing both the various complex phases and the corresponding phase diagrams of microemulsions. In some approaches, e.g., the random mixing model (RMM), the lattice parameter is of the order of the dimension of an oil or water domain and has been used as a length scale for computing a configurational entropy, the so‐called entropy of mixing, of the microemulsion. In the central and material section of this paper (Sec. III), we show that the fundamental length scale for the calculation of the entropy of mixing is of the order of the cube root of the volume per molecule—orders of magnitude smaller than the dimension of such a domain…

PhysicsLength scalePhase StudiesEntropyConfiguration entropyGeneral Physics and AstronomyThermodynamicsEntropy of mixingMicroemulsions ; Entropy ; Phase Diagrams ; Lattice Parameters ; Dispersions ; Phase StudiesUNESCO::FÍSICA::Química físicaPhase spacePhenomenological modelMicroemulsionsLattice ParametersStatistical physicsConfiguration spacePhase DiagramsPhysical and Theoretical ChemistryEntropy (energy dispersal)Dispersions:FÍSICA::Química física [UNESCO]Cube root
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Optical properties of TiO2 suspensions: Influence of pH and powder concentration on mean particle size

2007

WOS: 000250584100025

Work (thermodynamics)Settore ING-IND/24 - Principi Di Ingegneria ChimicaEffective sizeMaterials scienceTITANIUM-DIOXIDEScatteringPARTICULATE SUSPENSIONSGeneral Chemical EngineeringAnalytical chemistryPHOTON-ABSORPTIONAQUEOUS DISPERSIONSGeneral ChemistryPERFORMANCEHETEROGENEOUS PHOTOCATALYTIC SYSTEMSIndustrial and Manufacturing EngineeringSLURRY REACTORSRADIATION ABSORPTIONAgglomerateQUANTUM YIELDSPhotocatalysisParticleParticle sizePhysics::Chemical PhysicsAbsorption (chemistry)OPERATIONAL VARIABLES
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Interactions and structures in polydisperse suspensions of charged spherical colloids

2018

Colloidal suspensions are found a bit everywhere around us, in construction materials,in cosmetics, in food, in biology. They are composed of nanometric or micrometric particlesdispersed in a gas, a liquid or sometimes a solid.This thesis is about colloidal suspensions in ionic solutions, where colloids bear anelectric charge, for example silica particles in an aqueous solution of sodium chloride,at a basic pH. The colloids, here approximated by spheres, can vary significantly in size,which can have an important effect on the behavior of these systems.This study aims at improving the understanding of these charged colloidal suspensionsby theoretical models solved by numerical simulations.of…

[CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry[CHIM.THEO] Chemical Sciences/Theoretical and/or physical chemistryDispersions colloidalesNumerical simulationsColloidal dispersionsCoarse-GrainingSimulations numériquesMulti-Échelle
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