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 176 for “"critical temperature"”.
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Low magnetic field transitions of rhenium near the critical temperature
… curves were obtained with thermodynamic critical fields Hc between 4mG and 0.3G. The slope of Hc(T) vs. T was found to be not constant near the zero field transition temperature To. For Hc(T))>100mG a slope of 192 G/K was obtained, while for Hc(T)~5mg the slope decreased to 88 G/K. …
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Electron microscopy studies in electrical ceramics: Dielectric composites and high critical temperature superconductors
This thesis is principally concerned with the microstructural characterization of dielectric composites in the system BaTiO$\sb3$-NaNbO$\sb3$ by transmission electron microscopy (TEM), with the expressed purpose of determining the interrelationships that exist between chemical composition and …
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Processing-property relationships for high critical temperature ceramic superconductors in the bismuth-calcium-strontium-copper-oxygen system
This thesis reports research on high T$\sb{\rm c}$ Bi-Ca-Sr-Cu-O (BCSC) superconductors. The BCSC family of superconductors has three known superconducting phases: Bi$\sb2$Sr$\sb2$Cu$\sb1$O$\sb6$ (abbreviated as 2021, with a reported T$\sb{\rm c}$ of 22 K), Bi$\sb2$Ca$\sb1$Sr$\sb2$Cu$\sb2$O$\sb8$ …
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Two key questions about color superconductivity
… in proto-neutron stars cooling through the critical temperature for color-flavor locked quark matter. We include neutrino interactions with the fermionic excitations, important above and just below the critical temperature, and with the massless collective excitation, important just and well …
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Critical temperatures of superconducting solders
… (PCS), which needs to be warmed beyond its critical temperature at times in order to charge or discharge the magnet, with a mechanical switch that can be kept at its superconducting stage may be able to speed up the charging/discharging process. A malleable superconductor would be needed for …
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A persistent-mode MgB₂ 0.5-T/240-mm solid-nitrogen-cooled magnet for MRI
… magnets with field strengths above 1 T. A low-temperature superconductor of niobium titanium (NbTi) with a critical temperature of 9.8 K stands out among other superconductors because of its excellent mechanical properties, adequate electromagnetic properties and low manufacturing cost. Since …
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Anisotropy effects in the critical field of superconducting tin-indium alloys
Measurements have been made of the critical-field curve, Hc versus T, for eight superconducting dilute alloys of indium in tin near the critical temperature and at low temperatures extending to about 0.30 K. The effective magnitude of the superconducting energy gap is sensitive to the direction of …
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Octet and decuplet baryon masses at finite temperature
… and decuplet baryon masses are studied at finite temperature in the framework of finite energy QCD sum rules. In all cases it is found that the mass stays fairly constant over a range of temperatures, increasing sharply near the critical temperature for deconfinement Tc.
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Flux tube profiles at high temperature
… a static quark and anti-quark pair at high temperature by means of lattice simulations of Quantum Chromodynamics in the quenched approximation. Measuring the electric and magnetic components of the gluon field at temperatures close to the critical temperature of the phase transition from the …
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Growth of Semiconductor Thin Films by Pulsed Laser Deposition
… self-built. Parameters such as pressure, target temperature, and distance from the target to the substrate can be adjusted in the system. Scanning electron microscopy, energy dispersive X-ray spectroscopy, X-ray diffraction spectroscopy, Raman spectroscopy and ellipsometry were used to analyze …
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Electromagnetic pion form factor at finite temperature
… the pion in the space-like region, and at finite temperature, Fπ(Q²,T), is obtained from a Finite Energy QCD Sum Rule. The form factor decreases with increasing T, and vanishes at some critical temperature, where the pion radius diverges, thus signalling quark deconfinement.
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Interfacial properties of fluid phases in two dimensions and of three-component surfactant systems
… complex fluids. The first problem concerns the critical behavior of the thickness of interface of simple fluids in two dimensions of space. We study this problem using both theory and computer simulations. In our theoretical study of this problem, the equilibrium interface is assumed, in accord …
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ΣΥΝΘΕΣΗ ΚΑΙ ΜΕΛΕΤΗ ΜΟΝΟΔΙΑΣΤΑΤΩΝ ΚΑΙ ΔΙΔΙΑΣΤΑΤΩΝ ΑΓΩΓΙΜΩΝ ΟΡΓΑΝΙΚΩΝ ΥΛΙΚΩΝ
… SHOWED THAT. THE MOST OF THEM ARE METALS UNTIL A CRITICAL TEMPERATURE. SOME OF THEM REMAIN METALLIC DOWN TO VERY LOW TEMPERATURE. THE SALT (MDTTTF)2AΩI2 IS CONVERED TO SUPERCONDUCTOR AT 5K.
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Morphology and Properties of Amorphous Polyethylene Terephthalate
… ultraquenched from above its equilibrium melting temperature. Sufficiently rapid quenching rate below T(,g) and heating above the critical temperature before quenching were identified as necessary conditions to produce uniform morphology. Under other conditions, a conventional nodular morphology …
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Multiscale approaches on two-dimensional magnetic materials: from atomistic to mesoscale level
… two-dimensional magnets. To computed their critical temperature Tc, we parametrised the generalised Heisenberg model (XXZ) using DFT+U, and then we ran MC simulations. Most of the materials have a critical temperature below 100 K, but two of them, i.e. VPS3 and VSe2, may potentially show …
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Development of a Mechanistic-Based Approach to Evaluate Critical Conditions of Hot Mix Asphalt Mixtures
… asphalt (HMA) mixtures are believed to have a critical combination of temperature and traffic loading rate which will result in excessive permanent deformation. Designing the appropriate mixture type and properties are significantly important tasks that pavement engineers make on a routine …
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Cryogenic heat pipe for cooling high temperature superconductors with application to Electromagnetic Formation Flight Satellites
… formation flying spacecraft, EMFF uses high temperature superconducting (HTS) wire since it is able to carry a large current at low power. To achieve superconductivity, the HTS wire needs a cryogenic thermal control system to maintain the wire temperature below the critical temperature and …
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Resistance in Superconducting Epitaxial Niobium Nanowires
… in extremely narrow nanowires well below the critical temperature. However, attributing this additional resistance to quantum phase slips has been controversial. In part, this controversy is due to the amorphous nature of the majority of manufactured nanowires; such wires unavoidably contain …
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Planar tunneling spectroscopy of thin-film Nb, Nb/normal metal and Nb/semiconductor structures
… A thickness dependence of the superconducting critical temperature Tc and the superconducting gap parameter Δ have been observed for thin film superconductor/normal metal structures. Although many studies exist, the underlying mechanism is not fully understood. The niobium-semiconductor system …
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Heavy neutrino matter at finite temperature
… gas of massive neutrinos below some critical temperature, a condensed phase emerges, consisting of quasi-degenerate super-massive neutrino stars. These compact dark objects could play an important role in structure formation in this universe, as they might in fact provide the seeds …
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