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 48 for “"Cubic phase"”.
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Structural and optical properties of phase transition cubic phase gallium nitride for photonic devices
… Despite its success, the conventional hexagonal-phase GaN has fundamental deficits that hinders performance. These include: internal polarization field (~MV/cm2), high acceptor activation energy (260 meV), low hole mobility (20 cm2/V), and expensive substrates (Al2O3, SiC). The metastable …
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Cubic phase gallium nitride photonics integrated on silicon(100) for next-generation solid state lighting
… Despite its success, the conventional hexagonal-phase GaN has fundamental disadvantages in performance and cost that hinder market adoption. These include: internal polarization field ( MV/cm2), high acceptor activation energy (260 meV), low hole mobility (20 cm2/V), and expensive substrates …
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Analysis of Zincblende-Phase GaN, Cubic-Phase SiC, and GaAs MESFETs Including a Full-Band Monte Carlo Simulator
… of device properties for emerging wide-bandgap cubic-phase semiconductors. Though the wide-bandgap semiconductors have great potential as high-power microwave devices, many gaps remain in the knowledge about their properties. The simulations in this work are designed to give insight into the …
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Structural study of lipid bicontinuous cubic phases for cellular delivery
Lipid bicontinuous cubic phase is fundamentally interesting phase. Initially it is considered as an intermediate structure between lamellar and hexagonal phases due to its small phase space and complicated structure. With the development of structure characterization technologies, especially X-ray …
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Characterization of Boron Nitride Thin Films on Silicon (100) Wafer.
Cubic boron nitride (cBN) thin films offer attractive mechanical and electrical properties. The synthesis of cBN films have been deposited using both physical and chemical vapor deposition methods, which generate internal residual, stresses that result in delamination of the film from substrates. …
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Intermediate phases of surfactant - water mixtures
Intermediate phases in two non-ionic polyoxyethylene surfactantiD20 systems - nonaethylene glycol mono (1 1-oxa-14,18,22,26-tetramethylheptacosyl) ether (C30E09) and hexaethylene glycol n-hexadecyl ether (C15E05) have been studied. Both systems have a rhombohedral mesh phase with the space group …
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In-Situ, in Air, High-Temperature Phase Transformations in Rare-Earth Niobates and Titanium Oxides (Dysprosium and Yttrium) Using a Thermal-Image Furnace
… YNbO4 and DyNbO4 revealed the existence of a new cubic phase at elevated temperatures beyond the commonly known ferroelastic monoclinic-to-paraelastic tetragonal transformations. A series of high-temperature powder patterns of the pure hexagonal phase of DY2TiO5 was also collected in-situ, in air."
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The production of a lyotropic liquid crystal coated powder precursor through twin screw extrusion.
… twin screw extrusion was examined to produce the cubic phase (gel) for the development of controlled release formulation and for coating of very fine particles which cannot be achieved by traditional bead coaters. Controlled release formulations are beneficial in reducing the frequency of …
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Investigation of high-performance lithium-ion batteries based on highly conductive Li7La3Zr2O12 solid-state electrolyte and stable electrode-electrolyte interface
… highest theoretical capacity: 3,860 mAh g−1), cubic phase garnet-type Li7La3Zr2O12 (LLZO) solid-state electrolyte has attracted much attention for developing solid-state batteries with increased safety, higher energy density, and longer lifespan. Besides, the solid-state or liquid …
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Electrospun Titanium Dioxide and Silicon Composite Nanofibers for Advanced Lithium Ion Batteries
… nanofibers were made of amorphous carbon, rutile phase TiO<sub>2</sub>, and cubic phase Si nanoparticles. Sulfur was utilized as a template to form void structures within the TiO<sub>2</sub> nanofiber matrix. This provides the desired space for the Si expansion during the lithiation process. …
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Preparation, microstructure and properties of silicon carbide-dysprosia composites
… oxides), undergoes a displacive (monoclinic to cubic) phase transformation with volume expansion during cooling from high temperatures ($\approx$1850$\sp\circ$C). The effects of Dy$\sb2$O$\sb3$ additions on the microstructure and on selected mechanical properties of the composites were …
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Microfabrication methods to improve the kinetics of the yttria stabilized zirconia -- platinum -- oxygen electrode
… microfabrication of model systems with triple phase boundary lengths that varied over an order of magnitude to systematically quantify and ultimately improve the kinetics of platinum electrodes on the surface of yttria stabilized zirconia electrolytes. Platinum electrodes with well controlled …
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Precursor gas comparison for the growth of silicon carbide fibers via laser chemical vapor deposition
… were indexed by X-ray diffraction as the 3C-SiC cubic phase. The fibers were carbon-rich. In general, the TMS fibers had generally higher average stress at failures that were 2280 MPa as compared to the average DMS fibers being 1150 MPa. Considerable spread in the tensile strength at failure was …
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Substrate Dependence on the Growth and Texture of Lead Titanate and Lead Zirconate Titanate Thin Films by Metal Organic Chemical Vapor Deposition
… the PT transition temperature (i.e., grown in cubic phase), the film orientation is controlled by the anisotropic growth rates along different crystal directions, the epitaxial relationship and differential thermal stress between the film and substrate, as well as the transformation stress. On …
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Comparative study of physical properties of zirconia based dental ceramics
… (load 20-50 kg) and Raman spectroscopy. The phase transformation was also analysed on fracture surfaces of specimens that failed after biaxial flexural strength and subcritical crack growth test. The results of this project showed no significant difference in the mean biaxial flexural …
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Spatial Fringe Analysis Methods and their Application to Holographic Interferometry and Fringe Projection Techniques
… distributions corresponding to the interference phase and its first and second-order derivatives within the framework of a single interferometric configuration. Achieving this task would provide a significant advancement in the field of optical metrology as it allows for the measurement of …
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Four-Dimensional Coherence Sensing
… standard lens-based cameras, pinhole cameras, cubic-phase-plate enhanced high depth-of-field imagers, and coherence sensors such as the Rotational Shearing Interferometer. The thesis also demonstrates how the Rotational Shearing Interferometer can obtain infinite depth-of-field images, which is …
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First principles molecular dynamics simulation of carbon at high pressures and temperatures
… theory and we present an extensive study of the phases of carbon at high temperatures and pressures. Our extension provides a general method to treat electronic states at finite temperature or in non-equilibrium excited states, alleviates convergence problems that arise when iterative methods are …
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Elasticity measurements at extreme conditions: application to FeO and FeNi-alloy
… of fully anisotropic elasticity data for mineral phases. The single-crystal elastic constants of minerals, Cij, are elements of the fourth-rank elasticity tensor, which relates stress to strain. The fact that elastic strain also defines seismic wave propagation, the elastic tensor of minerals can …
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Synthesis, Characterisation and Functionalisation of CdSe Quantum Dots
… highlighted a transition of the crystallite phases obtained, from cubic zinc-blende to hexagonal wurtzite and back again to the cubic phase as a function of reaction time. The nature of this phase shift is believed to be due to the rapid growth along the {111} crystallite facets, with the …
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