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.
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Showing 1 to 20 of 26 for “"first order transition"”.
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The thermal expansion of ammonium chloride near the order-disorder transition
… of the volume of ammonium chloride near the first order transition at 242°K. This theory is able to account for a first order transition by considering the coupling between an elastic lattice system and the order-disorder system. The lattice system gives rise to non-singular terms in the …
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Ground states of a two-dimensional frustrated quantum antiferromagent Cs₂CuCl₄
… phase, which are separated by second order transition and a first order transition line for intermediate longitudinal field which ends up with a critical point.
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A Random First Order Theory of Liquid -Glass Transition
… of glassy dynamics based on an underlying random first order transition is developed to explain the magnitude and variation of free energy barriers for glassy relaxation. A variety of empirical correlations embodied in the concept of liquid ""fragility"" are shown to be quantitatively explained by …
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A Random first order theory of liquid-glass transition
… of glassy dynamics based on an underlying random first order transition is developed to explain the magnitude and variation of free energy barriers for glassy relaxation. A variety of empirical correlations embodied in the concept of liquid ""fragility"" are shown to be quantitatively explained by …
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Efficient Numeric Computation of a Phase Diagram in Biased Diffusion of Two Species
… and an excluded volume condition undergoes an order-disorder phase transition, controlled by the particle density and the field strength. This transition may be continuous (second order) or continuous (first order). Results from previous discrete simulations are shown, and a theoretical …
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Lattice parameter and thermal expansion in solid methane
… previous imprecise values in the literature. A first-order transition with a discontinuity in the lattice parameter of 0.1% was unambiguously observed to occur at 20.48 K on warming through the transition and at 20.39 K on cooling through the transition. An intrinsic hysteresis appeared to be …
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X-ray and neutron scattering studies of the Rb₂MnF₄ and Cu₁âõxMgx̳GeO₃ in an external magnetic field
… of low dimensional magnetic materials. The first is a neutron scattering study of Rb2MnF4, a nearly ideal two-dimensional square lattice Heisenberg antiferromagnet with S = 5/2. When this material is placed in a magnetic field on an extrapolation of the spin-flop phase boundary into the …
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Chiral symmetry restoration in the three-dimensional four-fermion model at non-zero temperature and density
… for the more complex problem of the chiral phase transition in Quantum Chromodynamics. It is shown that the critical properties near the finite temperature and zero density transition with a large number of fermion species N in the system can be described by mean field theory. It is also shown …
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The heat capacity of ammonium chloride near the order-disorder transition
… the behavior of ammonium chloride near the first order phase transition at 240K in terms of· a physical model that has singular and nonsingu1ar parts of the free energy coupled together. The singularity is normally associated with a second order phase transition, but it can lead to a first …
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In situ x-ray investigations of staging and sequencing potassium-graphite intercalation compounds
… a two-zone, high-temperature, x-ray furnace. The transition from stage 1 to stage 2 is found to be a two-phase process which does not require intermediate steps. For stage n, n > 2, stage mixing is shown to occur in thermodynamic equilibrium. The amount and relative concentration of admixed stages …
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Lane Preference in a Simple Traffic Model
… particles. At very high values of <I>p</I>, a first order transition takes the system to a spatially disordered state. Using Monte Carlo simulations to analyze the system, we find that the size of the cluster increases with lane preference. We also observe a region of negative response, where …
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Monte Carlo and Series Expansion Studies of the Anisotropic Driven Ising Lattice Gas Phase Diagram
… α. Under saturation drive, the shift in the transition temperature between ordered and disordered states can be either positive or negative, depending on α ≡ √(𝐽<sub>∥</sub>/𝐽<sub>⟂</sub>). The possible existence at large α of an additional phase ordered in only one direction is discussed. …
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X-ray study of the ordering phase transition at the Cu3Au (111) surface
We have studied the phase transition at the (111) surface of Cu3Au by glancing incidence x-ray scattering. The experiment was designed to approach the general question of surface behavior near a bulk first order phase transition. We have studied three aspects of the phase transition: the surface …
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Studies in random Ising spin systems
… Edwards-Anderson model has a spin-glass transition at zero temperature, in agreement with other calculations. We obtain an accurate estimate of the correlation-length exponent. We also find unexpectedly different critical behavior for different bond distributions. A simple …
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Numerical studies of the critical behaviour of non-commutative field theories
… using Hybrid Monte Carlo (HMC) techniques. The first system under study is a matrix regularization of the φ4 theory defined on the sphere. We develop a HMC algorithm together with an SU(2) gauge-fixing procedure in order to study the model. We extract the phase diagram of the model and give an …
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Trust, self-confidence, and operators' adaptation to automation
… pasteurization plant. The results of the first experiment indicated that the operators' trust changed dynamically, with the effects of transient and continuous faults spread over several trials. The second experiment showed that trust, combined with self confidence, corresponded to the …
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Electronic correlations in Lix̳ CoO₂
… (DMFT). Three main problems are addressed. First, the influence of hybridization among the eg and oxygen orbitals is studied using DFT and a modified Hubbard model which is solved within DMFT. It has long been known that doping holes into the t2g bands are accompanied by a rehybridization …
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Computational and experimental studies of acenes, starphenes and [60]fullerene derivatives
… of the rate-constant associated with the first-order transition state of a cyclohexene "boat-to-boat" inversion for each fullerene derivative provides evidence for a CH -- pi interaction estimated to be 0.95 kcal/mol.</p>
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Frustration from Frustration: Field Tuning, Vison Crystallisation, and Disorder in Quantum Spin Ice
… is close to a quantum spin ice discovery. In the first part of this thesis, I introduce a model of ‘breathing’ quantum spin ice captured at low energy by a new kind of staggered gauge theory. This theory shows a strongly first order transition to an inversion-broken phase, which may be thought of …
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Electrocaloric materials and devices
… to isothermal entropy change ∆S for hysteretic first-order transitions is described. An indirect route to adiabatic temperature change ∆T, without the need for field-resolved heat capacity data, is also described. Three temperature controllers were built: a cryogenic probe for 77-420 K with ∼5 …
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