Search results for "Transient"

showing 10 items of 623 documents

The Effect of Spectral Diffusion on the Saturation Transient Regime

1985

Saturation kinetics of inhomogeneous resonance lines has been investigated in very dilute ruby samples at T=4.2°K by the saturation transient technique. Experimental evidence of the effectiveness of intraline spectral diffusion is reported. Satisfactory agreement is found between the experimental results and a theoretical model in which spectral diffusion is ascribed to the time fluctuations of the hyperfine field. Spectral diffusion times of the order of 10-5 sec are determined.

Materials scienceField (physics)lawSaturation recoveryResonanceTransient (oscillation)Diffusion (business)Saturation (chemistry)Electron paramagnetic resonanceHyperfine structureMolecular physicslaw.invention
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SOIL IONIZATION DUE TO HIGH PULSE TRANSIENT CURRENTS LEAKED BY EARTH ELECTRODES

2009

This paper proposes a numerical model of the soil ionization phenomena that can occur when earth electrodes are injected by high pulse transient currents, as the one associated with a direct lightning stroke. Based on finite difference time domain numerical scheme, this model ascribes the electrical breakdown in the soil to the process of discharge in the air. In fact, as soon as the local electric field overcomes the electrical strength, the air in the voids trapped among soil particles is ionized, and the current is conducted by ionized plasma paths locally grown. The dimension of these ionized air channels is strictly dependent upon the local temperature. Thus, a local heat balance is en…

Materials scienceFinite-difference time-domain methodElectrical breakdownPlasmaMechanicsCondensed Matter PhysicsElectronic Optical and Magnetic MaterialsPulse (physics)Settore ING-IND/31 - ElettrotecnicaSettore MAT/08 - Analisi NumericaElectric fieldIonizationTransient (oscillation)transient currentsElectrical and Electronic EngineeringCurrent (fluid)numerical modelfinite difference schemeProgress In Electromagnetics Research B
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From equilibrium to steady state: The transient dynamics of colloidal liquids under shear

2008

We investigate stresses and particle motion during the start up of flow in a colloidal dispersion close to arrest into a glassy state. A combination of molecular dynamics simulation, mode coupling theory and confocal microscopy experiment is used to investigate the origins of the widely observed stress overshoot and (previously not reported) super-diffusive motion in the transient dynamics. A link between the macro-rheological stress versus strain curves and the microscopic particle motion is established. Negative correlations in the transient auto-correlation function of the potential stresses are found responsible for both phenomena, and arise even for homogeneous flows and almost Gaussia…

Materials scienceGaussianFOS: Physical sciencesCondensed Matter - Soft Condensed Matterconfocal microscopyMolecular dynamicssymbols.namesakeColloidddc:530General Materials ScienceColloids Glasses Shear Dynamics TransientMagnetosphere particle motionglass forming liquids under shearmode coupling serieDisordered Systems and Neural Networks (cond-mat.dis-nn)MechanicsCondensed Matter - Disordered Systems and Neural NetworksCondensed Matter PhysicsStart upmolecular dynamicsCondensed Matter::Soft Condensed MatterShear (geology)HomogeneousMode couplingsymbolsSoft Condensed Matter (cond-mat.soft)
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Simultaneous photonic and excitonic coupling in spherical quantum dot supercrystals

2020

Semiconductor nanocrystals, or quantum dots (QDs), simultaneously benefit from inexpensive low-temperature solution processing and exciting photophysics, making them the ideal candidates for next-generation solar cells and photodetectors. While the working principles of these devices rely on light absorption, QDs intrinsically belong to the Rayleigh regime and display optical behavior limited to electric dipole resonances, resulting in low absorption efficiencies. Increasing the absorption efficiency of QDs, together with their electronic and excitonic coupling to enhance charge carrier mobility, is therefore of critical importance to enable practical applications. Here, we demonstrate a ge…

Materials scienceGeneral Physics and AstronomyPhotodetectortransient absorptionPhysics::OpticsSupraparticlesquantum dots02 engineering and technology010402 general chemistry01 natural sciencesArticlesymbols.namesakeCondensed Matter::Materials SciencenanocrystalsMie theoryGeneral Materials ScienceRayleigh scatteringAbsorption (electromagnetic radiation)BiexcitonTransient absorptionsupercrystalsbusiness.industryCondensed Matter::OtherQuantum dotsSupercrystalsGeneral EngineeringMetamaterialself-assemblySelf-assembly021001 nanoscience & nanotechnologyCondensed Matter::Mesoscopic Systems and Quantum Hall Effect0104 chemical sciencesNanocrystalsNanocrystalsupraparticlesQuantum dotddc:540symbolsOptoelectronicsPhotonics0210 nano-technologybusinessPhysical Chemistry and Soft Matter
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Transient absorption and luminescence of LiNbO3 and KNbO3

2001

Abstract The results of time-resolved optical absorption spectra in congruent and stoichiometric LiNbO3 as well as KNbO3 crystals are reported. The role of different polaron types in transient absoiption and luminescence spectra and decay kinetics are discussed.

Materials scienceKineticsAnalytical chemistryLuminescence spectraCondensed Matter PhysicsPolaronElectronic Optical and Magnetic MaterialsOptical absorption spectraControl and Systems EngineeringUltrafast laser spectroscopyMaterials ChemistryCeramics and CompositesTransient (oscillation)Electrical and Electronic EngineeringLuminescenceStoichiometryIntegrated Ferroelectrics
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Quasi-static magnetoresistive sensor modeling for current-time conversion circuit applications

2011

In this paper we report a current-to-time converter (CTC) suitable for current sensor monitoring in low power applications. Based on a discrete resistence-to-frequency converter and a Giant MagnetoResistance (GMR) current sensor. Simulations have been done using a quasi-static electrical Verilog-A model for the GMR current sensor. A reduced set of parameters has been extracted to characterize the GMR sensor's behavior. The application has been analyzed making use of different sensors, whose device parameters were previously extracted. Finally, the accuracy of the models has been tested by comparing with experimental transient measurements.

Materials scienceMagnetoresistancebusiness.industryLow-power electronicsElectronic engineeringElectrical engineeringGiant magnetoresistanceCurrent sensorTransient (oscillation)businessDevice parametersQuasistatic processPower (physics)Proceedings of the 8th Spanish Conference on Electron Devices, CDE'2011
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Luminescence and Transient Optical Absorption in CdWO<sub>4</sub>

1997

Materials scienceMechanical EngineeringAnalytical chemistryScintillatorCondensed Matter Physicschemistry.chemical_compoundchemistryMechanics of MaterialsUltrafast laser spectroscopyCadmium tungstateGeneral Materials ScienceTransient (oscillation)LuminescenceAbsorption (electromagnetic radiation)Materials Science Forum
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Start-up and shutdown thermomechanical transient analyses of the IFMIF European lithium target system

2014

In the framework of the current IFMIF Engineering Validation and Engineering Design Activities (IFMIF/EVEDA) phase, ENEA is responsible for the design of the European concept of the IFMIF lithium target system which foresees the possibility to periodically replace only the most irradiated and thus critical component (i.e., the backplate) while continuing to operate the rest of the target for a longer period (bayonet backplate concept). With the objective of evaluating the performances of the system in terms of temperature, stress and displacement fields evolution during start-up and shutdown phases, an uncoupled thermomechanical transient analysis has been performed in close collaboration w…

Materials scienceNuclear engineeringIFMIF Target assembly Bayonet backplate Thermomechanics Start-up ShutdownStart-upShutdown7. Clean energy01 natural sciencesThermomechanic010305 fluids & plasmasStress (mechanics)ThermomechanicsTarget assembly0103 physical sciencesThermalIFMIFGeneral Materials ScienceNeutron010306 general physicsBayonet backplateSettore ING-IND/19 - Impianti NucleariCivil and Structural EngineeringMechanical EngineeringNuclear dataFinite element methodIFMIF;Bayonet backplate;Thermomechanics;Start-up;Shutdown;Target assemblyNuclear Energy and EngineeringSystems designTransient (oscillation)Engineering design process
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A novel flexible approach for prediction and on line diagnostic of partial discharge

2004

Partial discharges (PD), due to unavoidable local defects produced by the industrial manufacturing process, can determine local erosion of the material that may cause the electrical breakdown of the component in which the dielectric material represents the fundamental part. Recently, improved diagnostics of electrical insulation systems by means of electric PD measurements through a stochastic processing of the acquired data have been carried out. In this way, the identification of the defects as well, as the separation of multiple defects simultaneously active, have been performed. In this paper, a novel flexible approach for the on-line characterization of the defects in a dielectric mate…

Materials sciencePartial dischargeLiquid dielectricElectrical breakdownElectronic engineeringMechanical engineeringTransient responseElectrical treeingDielectricLine (electrical engineering)Characterization (materials science)
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Intrinsic and extrinsic point-defects in vapor transport grown ZnO bulk crystals

2006

Vapor transport grown ZnO bulk crystals were characterized by electrical, optical and magnetic resonance spectroscopy. The experiments show that the residual carrier concentration is caused by residual H, Al, Ga, and oxygen vacancies in the material. Annealing the samples in O 2 at about 1000 °C (2 atm, 20 h) reduces the H and V O donor concentration by typical one order of magnitude. The photoluminescence and DLTS results suggest a correlation between the broad unstructured emission at 2.45eV (green band) and a donor level 530 meV below the conduction band (E4).

Materials sciencePhotoluminescenceDeep-level transient spectroscopyAnnealing (metallurgy)Analytical chemistryCrystal structureCondensed Matter PhysicsCrystallographic defectElectronic Optical and Magnetic MaterialsNuclear magnetic resonanceCharge carrierElectrical and Electronic EngineeringSpectroscopyLuminescencePhysica B: Condensed Matter
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