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 9 of 9 for “"first-order transitions"”.
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Phase diagram for the S equals one-half and J equals three-halves Kondo lattice model
… is represented by finite hybridization. Magnetic ordering is examined via ordering vectors, but coexistence with the Kondo phase is not allowed. Phase diagrams are produced in S=1/2 and J=3/2 with second-order transitions at Kondo-paramagnetic and magnetic-paramagnetic boundaries, and first order …
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Analyse der viskoelastischen Eigenschaften von Poly(tetrafluorethylen) im Bereich des Beta-Übergangs
… ß-relaxation is admittedly complicated by two first order transitions in the crystalline phase at 19°C and 30°C. The basis of the investigations are isothermal creep tests on preconditioned PTFE sheets with a degree of crystallinity of 27%. The creep compliance is converted into relaxation data …
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On Quantum Simulators and Adiabatic Quantum Algorithms
… quantum computing. We demonstrate that the first-order correction, which has frequently been used as a condition for adiabatic quantum computation, does not yield a good estimate for the computational error. Therefore, a more general criterion is proposed, which includes higher-order …
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Magnetische Phasenübergänge im Hubbard-Modell mit Frustration
In this thesis magnetic transitions accompanying the correlation-driven metal-insulator transition in the Hubbard Model with frustration are discussed. Spin systems are called frustrated if there are couplings between sites that hamper the transition to an antiferromagnetically ordered ground …
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Phase Transitions in Disordered Systems: I. Exciton/electron-Hole Liquid/plasma System in Germanium and Ii. Amorphous Ferromagnets and Spin Glasses
… recombination luminescence. We observe a line of first-order transitions between the exciton gas and e-h gas occurring up to 7 K which we associate with the M-I transition. This is well above the temperature of the L-G critical point which we found to be 4.5 (+OR-) 0.5 K with a critical density of …
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Exploring new materials for caloric cooling
… are explored by exploiting latent heat from first-order phase transitions in a smart polymer driven by stimuli unexplored in the field of calorics thus far. Despite displaying large thermally driven entropy changes (|∆S₀|) near superionic transitions, the superionic conductors studied here …
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High-temperature superconductivity in a family of iron pnictide materials
… of a splitting of the structural and magnetic transitions in the first species. I also discuss the effect of pressure, which can lead to superconductivity in lightly doped samples for very modest pressures; and annealing, which increases transition temperatures within samples, on a limited …
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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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Phase transitions in disordered systems: I. exciton/electron-hole liquid/plasma system in germanium and II. amorphous ferromagnets and spin glasses
… recombination luminescence. we observe a line of first-order transitions between the exciton gas am p-h gas occurring UP to 7 K which we associate with the M-I transition. '!his is well above the temperature of the L-G critical point which we found to be 4.5 + 0.5 K with a critical density of 16 3 …