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Showing 1 to 16 of 16 for “"Second sound"”.
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Steady-state and second-sound measurements of Kapitza resistance
Submitted by Carolyn Mead (cmead2@illinois.edu) on 2011-06-20T18:50:47Z No. of bitstreams: 1 1980_katerberg.pdf: 2270499 bytes, checksum: 43be2016e3e480be2f087f61ef3b8472 (MD5)
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Quasi-particle Breakdown and Heat Transport in a Homogeneous Strongly-interacting Fermi Gas
… in a superfluid it propagates as a wave, called second sound. The measured speed of second sound yields the superfluid fraction, which quantifies the inertia against phase twists. The damping time scales of second sound and heat diffusion show a minimum diffusivity on the order of the quantum …
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Tuneable homogeneous Bose fluids close to and far from equilibrium
… the observation of the cooling and purification. Second, we describe our simultaneous observation of first and second sound, a phenomenon that is central for the concept of superfluidity. Sound waves occur close to equilibrium, as a linear response to weak perturbations. With liquid helium, the …
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Superfluidity in a uniform two-dimensional Bose gas
… atomic gases, is the existence of two kinds of sound excitations, the first and second sound. Unlike its three dimensional counter-part, however, superfluidity in two dimensions is associated with the pairing of vortices of opposite circulation as described by the Berezinskii-Kosterlitz-Thouless …
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Habituation to Auditory Stimuli by Captive African Elephants (Loxodonta Africana)
… stimuli –buzzing by a disturbed beehive and the sound of banging on pots and pans, as these sounds invoke alert and avoidance behaviors in wild elephants as part of humanelephant conflict mitigation. I hypothesized that elephants would initially exhibit strong reactions to both sounds, but these …
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Quantum turbulence generated by moving grids
… is investigated using the attenuation of second sound. We produce turbulence inside a short channel totally submersedin liquid helium-II. The turbulence is produced by a superconducting, magnetically levitated linear motor, with a grid attached to the top of the armature. The theory …
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Phonon-quasiparticle interactions in dilute solutions of He3 in superfluid He4
… to determine the attenuation' of both first and second sound and the kinetic coefficients in dilute solutions. There is good overall agreement with available experimental results for first sound attenuation.
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Phonon hydrodynamic transport at elevated temperature
… can be observed up to 90 K. Using a sub-picosecond transient grating technique, we directly observed second sound in graphite at record-high temperatures of 200 K. With the enlarged grating-period window, we firstly reported the dispersion of thermal wave, whose velocity increases with …
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Thermal transport at the nanoscale : from fourier diffusion to phonon hydrodynamics
… conductivity across one order of magnitude. Secondly, we experimentally and theoretically examine deviations from the diffusive regime of thermal transport in SiGe alloys, thereby extending current theory and experiment to the study of size effects in thermal transport to opaque materials. …
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Phonon hydrodynamic transport at elevated temperature
… can be observed up to 90 K. Using a sub-picosecond transient grating technique, we directly observed second sound in graphite at record-high temperatures of 200 K. With the enlarged grating-period window, we firstly reported the dispersion of thermal wave, whose velocity increases with …
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Sound Waves and Turbulence in Two-dimensional Bose Gases
… (BKT) phase transition, while in the second one we study the out-of-equilibrium dynamics of the system. Our experiments are performed using a gas of $^{39}$K atoms confined in a 2D box trap, which guarantees the homogeneous gas density and allows tuneability of the interaction …
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The Effect of Motor Responses Versus Verbal Responses on Sound Localization Accuracy in Young Children with Normal Hearing
<p>Rationale. Sound localization is the ability to pinpoint the origin of a sound source within an auditory space. This ability is essential for safety, orientation, and communication. Poor sound localization abilities, especially in young children, can have a negative impact on academics and …
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Study of Ultracold Fermi Gases in the BCS-BEC Crossover: Quantum Monte Carlo Methods, Hydrodynamics and Local Density Approximation.
… of state. We study the propagation of first and second sound in ultracold Fermi gases in cylindrical geometry, using the hydrodynamic equations of superfluids.
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Transport of phonons and electrons in thermoelectric materials and graphene
… motion of phonons, phonon Poiseuille flow, and second sound, all of which are not possible in both diffusive and ballistic phonon transport.
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Non-Equilibrium Thermodynamics of porous media filled by a fluid flow and of rigid bodies with an internal tensorial field influencing the thermal phenomena.
… some aspects of the arguments presented in the second, third, fourth, and seventh Chapters. Regarding the first Part, the influence of porous channels filled by fluid on the other fields occurring inside the media is illustrated by the introduction of a structural permeability tensor à la …
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ΠΡΟΒΛΗΜΑΤΑ ΤΗΣ ΓΕΝΙΚΕΥΜΕΝΗΣ ΘΕΡΜΟΕΛΑΣΤΙΚΟΤΗΤΑΣ ΚΑΙ ΕΠΕΚΤΑΣΗ ΤΗΣ ΣΤΑ ΣΙΔΗΡΟΜΑΓΝΗΤΙΚΑ ΥΛΙΚΑ
IN THIS THESIS (I) A COMPARATIVE STUDY OF THE COUPLED BIOT'S THEORY OF THERMOELASTICITY IS PRESENTED AS WELL AS OF THE GENERALIZED THEORIES OF LORD AND SHULMAN, LEBON AND GREEN AND LINDSAY. ALSO THE PROBLEM OF THE PROPAGATION OF THERMOELASTIC WAVES IN AN INFINITE CYLINDER IS STUDIED. (II) THE FIELD …