Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 48 for “"Metastability"”.
-
Quantum Trajectories: Metastability, Gauge Freedom and Weak Symmetries
… Firstly, we consider how systems exhibiting metastability behave at the level of stochastic quantum trajectories. In doing so we make comparisons to classical theories of metastability, where trajectories exhibit fast relaxation into distinct phases and slow transitions between them. We also …
-
Theoretical advancements towards understanding crystalline metastability during materials synthesis
… questions regarding the fundamental nature of metastability: Which metastable phases can form? Under which conditions will they form? We will employ a variety of computational and theoretical approaches to elucidate quantitative insights to these two questions. To better predict which …
-
Metastability of Magnetic Nanoparticles in Magnetization Relaxation with Different Dynamics and Distributions of Magnetic Anisotropy
We study the metastability of magnetic nanoparticles with size distributions. We simulate an array of magnetic nanoparticles with a spin S = 1 ferromagnetic Blume-Capel model on a square lattice. Studying decays of the metastable state in the Blume-Capel model at low temperatures requires an …
-
Understanding the origins of metastability in thin film growth; tantalum and the early group VB-VIB metals
Tantalum (Ta) is a metal that is highly prized for its applications in a variety of industries, including the microelectronics industry, where it is largely used in thin film modifications in order to achieve various electronic, magnetic and structural capabilities in solid-state devices. Ta …
-
Rapid Solidification and Undercooling of Aluminum-Germanium Alloys: Characterization and Control of Microstructure (Metastability, Metallic Glass, Electron Microscopy)
A determination of the importances of undercooling and cooling rate in the microstructural development of Al-Ge alloys during rapid solidification has been carried out. A new technique has been developed which allows for such determinations to be performed directly in a transmission electron …
-
Synthesis And Characterization Of Transition Metal Arsenide Nanocrystals And The Metastability And Magneto-Structural Phase Transition Behavior Of Mnas Nanocrystals
<p>This dissertation study focuses on (1) probing the magneto-structural phase transformation in nanoscale MnAs; (2) evaluation of the size-dependent phase stability of type-B MnAs (prepared by rapid injection); and (3) developing a general synthetic method for transition metal arsenide …
-
Measurement of the efficiency of a flashing flow nozzle
… measurement, a parameter to quantify the metastability in the nozzle flow was defined and empirical correlations were developed for both. The experimentation illustrated that the efficiency did indeed increase when flow conditions were closer to equilibrium. Efficiency and metastability …
-
Performance measurements of a flashing flow nozzle
… flow nozzle was quantified by efficiency and metastability measurements. Efficiency was calculated over a range of operating conditions, by using both inlet and exit conditions and the nozzle thrust. Metastability was quantified by a parameter that compared the experimental mass flow rate with …
-
Development of a polarized Helium-3 ion source for RHIC using the electron beam ion source
… atoms will be polarized using the technique of metastability exchange optical pumping (MEOP), and will then be flowed into the newly commissioned Electron Beam Ion Source (EBIS). Fully stripped 3He++ ions will be extracted and their polarizations measured at low energies before acceleration in …
-
A study of the chiral phase transition in the nonlinear sigma model
… A variety of numerical techniques, including metastability analysis, reduced cumulant of the energy, and finite sized scaling were employed to determine the transition for both flavors using the U(N) $\times$ U(N) and SU(N) $\times$ SU(N) flavor symmetries. The results of these simulations for …
-
A study of the chiral phase transition in the non-linear sigma model
… A variety of numerical techniques, including metastability analysis, reduced cumulant of the energy, and finite sized scaling were employed to determine the transition for both flavors using the U(N)xU(N) and SU(N)xSU(N) flavor symmetries. The results of these simulations for the finite …
-
Hydrogen-Induced Transformations in Metastable High Entropy Alloys
… discover H effects and their interactions with metastability. In the first part of this work, we explore H-induced transformations in one metastable alloy, Fe₄₅Mn₃₅Co₁₀Cr₁₀. To this end, we electrochemically introduce H to the samples, quantify the hydrogen evolution by thermal desorption …
-
An optical-electrical sub-sampling down-conversion receiver with continuous-time [Sigma] [Delta] modulation
… converter (DAC) clock jitter and quantizer metastability issues that plague traditional electronic implementations. The optical-electrical converter achieves 76.5 dB of SNR (12.4 ENOB) with a 1 MHz signal bandwidth and a sampling rate of 780 MHz. The chip was implemented using a standard …
-
Uniaxial optical phase change metamaterials
… between states, fast switching speeds, and high metastability. Here, we theoretically investigate the reflectance and form birefringence of GST-based optical metamaterials. These optical properties are simulated on the basis of effective medium theory (EMT) and transfer matrix method (TMM). The …
-
Thermodynamics of Micellar Lyotropic Liquid Crystals
… protocols employed, indicating the metastability of this mesophase. We further illustrate the non-specific nature of FK phase formation in soft materials by the discovery of a σ phase on self-assembly of hydrated non-ionic polyethylene-block-poly(ethylene oxide) surfactants. For the …
-
Stress Effects on Phase Morphological and Compositional Non-uniformity in Intercalation Compounds
… concerns the effect of coherency stress on the metastability of solid solution in nanoscale intercalation compounds that are increasingly employed in batteries. Previous theoretical works predict that stress can significantly suppress phase separation and extend the solid solution regime in …
-
The Complex Behavior of Nitrogen Under Pressure: Ab Initio Simulation of the Properties of Structures and Shock Waves
… structure leading to increased range of metastability, even to zero pressure at low T. I find characteristics of both the cubic gauche and hexagonally packed chain structure in the amorphous structure, and conclude that the experimental structure may be an amorphous collection of small …
-
Experiments with Bose-Einstein condensates in a double-well potential
… relaxation process serves as a model system for metastability in condensates and provides a test for quantum kinetic theories of condensate formation.
-
Investigations of the gallium nitride, aluminum nitride and indium nitride semiconductors: Structural, optical, electronic and interfacial properties
… system for short wavelength optical devices. The metastability of these crystals has led us to the conclusion that the zincblende nitrides are not a promising candidate for these applications due to their tendency to nucleate wurtzite domains. Bulk samples of zincblende GaN and InN and wurtzite …
Page 1 of 3