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Experiments at temperatures below one degree absoluteCroft, Anthony Julian January 1952 (has links)
No description available.
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Some applications of the quantum cell modelFernandez, Julio Fernando 12 1900 (has links)
No description available.
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The structure and thermodynamic properties of amorphous metals at low temperatures /Gibbs, Simon John. January 1978 (has links)
No description available.
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A d.c. SQUID susceptometer for the study of dHvA oscillations in heavy fermion compoundsThain, A. January 1999 (has links)
No description available.
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Low temperature calorimetric studies of some inorganic compoundsClay, R. M. January 1965 (has links)
No description available.
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The properties of semiconductors at low temperaturesPeskett, Guy D. January 1967 (has links)
No description available.
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Experiments on ultrasonics at microwave frequenciesLewis, M. F. January 1964 (has links)
No description available.
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Studies in magnetism at low temperaturesThorp, T. L. January 1966 (has links)
No description available.
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Nuclear orientation at very low temperaturesMalakoff, Walter January 1969 (has links)
One of the recently developed methods for studying nuclei depends on the orientation of the spin axes of the nuclei with respect to some axis fixed in space. Since there is an association between the angular momentum properties of a nuclear system and directional effects in the absorption or emission of radiation by such a system, this nuclear ordering is characterized by anisotropic effects in the interaction of the nuclei with radiation, whether particle or electromagnetic.
This thesis encompasses the preliminary work done in assembling a system consisting of cryogenic equipment and electronics to measure the anisotropy in radiation emitted from radioactive nuclei oriented in a ferromagnetic host lattice (iron) at very low temperatures (∾0.01°K) and to observe the changes in anisotropy with changes in temperature.
Chapter 1 contains a condensed account of the information that can be obtained from oriented nuclei, the methods of producing oriented nuclei and the theory required for extracting information from the observed anisotropy.
Chapter 2 describes the low temperature apparatus and-includes a description of the low temperature cryostat, the Dewar vessels, the specimen assembly, the superconducting solenoid, and the polarizing solenoid. Chapter 3 deals with thermometry at low temperatures, the technique used for cooling adiabatically and the preparation of the Co⁶º specimen used for thermometry.
Chapter 4 explains the function of each module of electronics used in the experimental configuration.
Nuclear orientation of Co⁶º is covered in Chapter 5 and includes an analysis and discussion of results.
Chapter 6 outlines the improvements to be made in the design of a new low temperature system and includes a brief summary of the future program of studies in nuclear orientation at very low temperatures. / Science, Faculty of / Physics and Astronomy, Department of / Graduate
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Application of Particle Tracking Velocimetry to Thermal Counterflow and Towed-Grid Turbulence in Helium IIUnknown Date (has links)
The superfluid phase of helium-4, known as He~II, is predominantly used to cool low-temperature devices. It transfers heat by a unique
thermally driven counterflow of its two constituents, a classical normal fluid and an inviscid superfluid devoid of entropy. It also has
potential use for economical reproduction and study of high Reynolds number turbulent flow due to the extremely small kinematic viscosity and
classical characteristics exhibited by mechanically driven flow. A number of diagnostic techniques have been applied in attempts to better
understand the complex behavior of this fluid, but one of the most useful, flow visualization, remains challenging because of complex
interactions between foreign tracer particles and the normal fluid, superfluid, and a tangle of quantized vortices that represents turbulence in
the superfluid. An apparatus has been developed that enables application of flow visualization using particle tracking velocimetry (PTV) in
conjunction with second sound attenuation, a mature technique for measuring quantized vortex line density, to both thermal counterflow and
mechanically-driven towed-grid turbulence in He~II. A thermal counterflow data set covering a wide heat flux range and a number of different
fluid temperatures has been analyzed using a new separation scheme for differentiating particles presumably entrained by the normal fluid ("G2")
from those trapped on quantized vortices ("G1"). The results show that for lower heat flux, G2 particles move at the normal fluid velocity vn,
but for higher heat flux all particles move at roughly vn/2 ("G3"). Probability density functions (PDFs) for G1 particle velocity vp are
Gaussian curves with tails proportional to |vp|⁻³, which arise from observation of particles trapped on reconnecting vortices. A probable link
between G1 velocity fluctuations and fluctuations of the local vortex line velocity has been established and used to provide the first
experimental estimation of c₂, a parameter related to energy dissipation in He~II. Good agreement between the length of observed G2 tracks and a
simple model for the mean free path of a particle traveling through the vortex tangle suggests that flow visualization may be an alternative to
second sound attenuation for measurement of vortex line density in steady-state counterflow. Preliminary PTV and second sound data in decaying
He~II towed-grid turbulence shows agreement with theoretical predictions, and enables reliable estimation of an effective kinematic viscosity
and calculation of longitudinal and transverse structure functions, from which information about the energy spectrum evolution and intermittency
enhancement can be obtained. / A Dissertation submitted to the Department of Mechanical Engineering in partial fulfillment of the requirements
for the degree of Doctor of Philosophy. / Fall Semester 2018. / August 21, 2018. / Includes bibliographical references. / Wei Guo, Professor Directing Dissertation; Jorge Piekarewicz, University Representative; William Oates,
Committee Member; Kunihiko Taira, Committee Member.
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