Search results for "Solid"

showing 10 items of 3575 documents

Chemistry and properties of solids with the [NZP] skeleton

1993

Abstract Solids with an [NZP] skeleton in their structure from a very broad family presenting very different properties with varying chemical composition. These properties range from radioactive nuclide immobilization and insulation to ionic and/or electronic conduction, extending to the field of very low thermal expansion among others. The open [NZP] skeleton provides the stability and flexibility necessary to form continuous ranges of solid solution, allowing the tailoring of the best composition-property-structure material. Chemical activity may become particularly high at the surface and absorption reactions and catalytic properties have the highest interest at present. In this paper, c…

Phase transitionIon exchangeChemistryIonic bondingGeneral ChemistryCondensed Matter PhysicsThermal conductionThermal expansionPolymorphism (materials science)Chemical physicsPhysical chemistryGeneral Materials ScienceAnisotropySolid solutionSolid State Ionics
researchProduct

Mass spectrometry of surfactant aggregates.

2012

In contrast with the enormous amount of literature produced during many decades in the field of surfactant aggregation in liquid, liquid crystalline and solid phases, only a few investigations concerning surfactant self-assembling in the gas phase as charged aggregates have been carried out until now. This lack of interest is disappointing in view of the remarkable theoretical and practical importance of the inherent knowledge. The absence of surfactant–solvent interactions makes it easier to study the role of surfactant–surfactant forces in determining their peculiar self-assembling features as well as the ability of these assemblies to incorporate selected solubilizate molecules. Thus, t…

Phase transitionLiquid crystallineChemistryAnalytical chemistrySupramolecular chemistryGeneral MedicineMass spectrometryAtomic and Molecular Physics and OpticsMass SpectrometryPhase TransitionGas phaseSurface-Active AgentsPulmonary surfactantChemical physicsSolid phasesMoleculeGasesSpectroscopyEuropean journal of mass spectrometry (Chichester, England)
researchProduct

Combined Raman scattering andab initioinvestigation of pressure-induced structural phase transitions in the scintillatorZnWO4

2008

The room-temperature Raman scattering was measured in ${\text{ZnWO}}_{4}$ up to 45 GPa. We report the pressure dependence of all the Raman-active phonons of the low-pressure wolframite phase. As pressure increases additional Raman peaks appear at 30.6 GPa due to the onset of a reversible structural phase transition to a distorted monoclinic $\ensuremath{\beta}$-fergusonite-type phase. The low-pressure and high-pressure phases coexist from 30.6 to 36.5 GPa. In addition to the Raman measurements we also report ab initio total-energy and lattice-dynamics calculations for the two phases. These calculations helped us to determine the crystalline structure of the high-pressure phase and to assign…

Phase transitionMaterials scienceAb initioCondensed Matter PhysicsMolecular physicsElectronic Optical and Magnetic MaterialsCondensed Matter::Materials Sciencesymbols.namesakeAb initio quantum chemistry methodssymbolsOrthorhombic crystal systemRaman spectroscopyRaman scatteringMonoclinic crystal systemSolid solutionPhysical Review B
researchProduct

Phase Transitions and Electrocaloric Effect in Ca-Modified Na1/2Bi1/2TiO3–SrTiO3–PbTiO3Solid Solutions

2014

Phase transitionMaterials scienceAcoustics and UltrasonicsElectrocaloric effectThermodynamicsElectrical and Electronic EngineeringInstrumentationSolid solutionIEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
researchProduct

Negative pressures in CaWO4 nanocrystals

2009

Tetragonal scheelite-type CaWO4 nanocrystals recently prepared by a hydrothermal method show an enhancement of its structural symmetry with the decrease in nanocrystal size. The analysis of the volume dependence of the structural parameters in CaWO4 nanocrystals with the help of ab initio total-energy calculations shows that the enhancement of the symmetry in the scheelite-type nanocrystals is a consequence of the negative pressure exerted on the nanocrystals; i.e., the nanocrystals are under tension. Besides, the behavior of the structural parameters in CaWO4 nanocrystals for sizes below 10 nm suggests an onset of a scheelite-to-zircon phase transformation in good agreement with the predic…

Phase transitionMaterials scienceCalcium compoundsAb initioUNESCO::FÍSICAGeneral Physics and AstronomyNanoparticleNanostructured materialsCrystal symmetryCrystallographyTetragonal crystal systemNanocrystalAb initio quantum chemistry methodsChemical physicsTotal energy:FÍSICA [UNESCO]Phase (matter)Ab initio calculations ; Calcium compounds ; Crystal growth from solution ; Crystal symmetry ; Nanostructured materials ; Solid-state phase transformations ; Total energySolid-state phase transformationsAb initio calculationsCrystal growth from solutionMonoclinic crystal system
researchProduct

Production and Properties of (1-x)Pb(Sc<sub>1/2</sub>Nb<sub>1/2</sub>)O<sub>3</sub> – xPb(Yb<sub>1/2</su…

2004

Phase transitionMaterials scienceChemical engineeringMechanics of MaterialsMechanical EngineeringGeneral Materials ScienceHot pressingSolid solutionKey Engineering Materials
researchProduct

Phase Transitions in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3Solid Solutions

2010

All sequential steps of transfer from relaxor to normal ferroelectric phase transition are found in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 if concentration of PbTiO3 increases. The relaxor properties in Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 solid solutions are described by the power law and Vogel-Fulcher relationship. Concentration dependence of the relevant parameters is discussed. Stability of relaxor and ferroelectric phases is discussed by analyzing behaviour of critical electric fields.

Phase transitionMaterials scienceConcentration dependenceCondensed matter physicsElectric fieldCondensed Matter PhysicsStability (probability)Power lawFerroelectricityElectronic Optical and Magnetic MaterialsSolid solutionFerroelectrics
researchProduct

Some nonlinear properties of ferroelectric smart materials

2001

Four types of nonlinear properties of ferroelectric smart materials have been considered: nonlinear dynamics of the paraelectric–ferroelectric interphase boundaries, nonlinear equilibrium excitations}domain walls, nonlinear response of the domain structure near the first-order phase transition}wetting of domain walls}andnonlinear effects causedby external high magnetic fields. The above mentioned nonlinearities have been studied in ðBa; SrÞTiO3ðBSTÞ and PbðZr; TiÞO3ðPZTÞ. # 2001 Elsevier Science B.V. All rights reserved.

Phase transitionMaterials scienceCondensed matter physicsCondensed Matter PhysicsSmart materialFerroelectricityElectronic Optical and Magnetic MaterialsMagnetic fieldCondensed Matter::Materials ScienceNonlinear systemDomain (ring theory)WettingElectrical and Electronic EngineeringSolid solutionPhysica B: Condensed Matter
researchProduct

PHASE TRANSITIONS IN Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 SOLID SOLUTIONS

2009

ABSTRACT Studies of nature of polarization in ternary solid solutions of Na1/2Bi1/2TiO3-SrTiO3-PbTiO3 were done, using measurements of dielectric properties and polarization hysteresis loops. Various stages of relaxor behavior depending on concentration of PbTiO3 were established and compared with other known ferroelectric relaxors.

Phase transitionMaterials scienceCondensed matter physicsDielectricCondensed Matter PhysicsPolarization (waves)FerroelectricityElectronic Optical and Magnetic MaterialsControl and Systems EngineeringMaterials ChemistryCeramics and CompositesElectrical and Electronic EngineeringTernary operationSolid solutionIntegrated Ferroelectrics
researchProduct

Dielectric Properties and Conductivity of Ferroelectric LixNa1-xTa 0.1Nb0.9O3 Solid Solutions

2011

Results of a study of dielectric properties and conductivity of ferroelectric perovskite solid solutions of the LixNa1-xTa0.1Nb0.9O3 (х = 0.03–0.135) series with the 290–700 K thermal range and frequencies from 25 to 106 Hz are reported. The charge in this kind of materials is shown to be transferred by Li+ ions the contribution from bulk transport of ions dominating. A first order phase transition close to the second order transitions proceeds in LixNa1-xTa0.1Nb0.9O3 solid solutions within the thermal range examined. The increase of Li concentration enhances the features of the second order transition.

Phase transitionMaterials scienceCondensed matter physicsDielectricConductivityCondensed Matter PhysicsFerroelectricityElectronic Optical and Magnetic MaterialsIonControl and Systems EngineeringThermalMaterials ChemistryCeramics and CompositesElectrical and Electronic EngineeringPerovskite (structure)Solid solutionIntegrated Ferroelectrics
researchProduct