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 15 of 15 for “"Effect of doping"”.
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Model of reflectance of thermophotovoltaic cell and cold plate
The reflectivity of a gold-plated cold plate, and mounted multi-junction photovoltaic cells, is studied in the context of a thermal energy grid storage system. The emitter is modeled as a black body emitter. Improving the efficiency of the system requires high reflectance below the bandgap energy …
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A first principles investigation of transitional metal doping in lithium battery cathode materials
The goal of this work is to understand the properties of mixed-metal intercalation oxides. Using first-principles methods, the effect of doping on the mixing, energetic, and voltage properties as well as the phase diagrams of lithium transition-metal oxides for lithium battery cathode materials was …
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Quasi-one-dimensional magnetism in TiOCl and a theory of a lightly doped dimerized insulator
… and unconventional magnetism. The first part of this thesis is related to this rich and diverse subject, where TiOCl is studied as an example of an S = 1/2 layered Mott insulator. Earlier experiments on this material indicating two-dimensional spin-liquid behavior are reviewed critically and …
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Heat Transfer Issues in Thin-Film Thermal Radiation Detectors
… The current study provides an analytical model of the notional thermal radiation detector that takes into account thermal transport phenomena, such as the contact resistance between the layers of the detector, and is suitable for use in parameter estimation. It was found that the responsivity of …
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The Synthesis, Characterisation and Electrical Conductivity of Poly(Styrene-Co-Acetylene)
… novel metathesis catalyst for the polymerisation of acetylene has been developed. The polyacetylene produced by this new catalyst has been characterised by infra-red and NMR spectroscopy. The conductivity of the pristine material has been studied as a function of temperature, pressure and …
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Electronic charge injection and transport in organic field-effect transistors
… based on organic semiconductors, such as field-effect transistors (FETs) and light emitting diodes have attracted much interest as possible inexpensive and flexible alternatives to inorganic devices. Despite considerable improvement in device properties, a better understanding of the nature of …
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Ionic liquids as a dissolution system for preparing graphene/cellulose based materials
… as in the textile industry. However, because of the dense hydrogen bonding present in cellulose, it presents severe problems for dissolution and processing. Room temperature ionic liquids, especially those which contain strong hydrogen bond acceptor anions, have been reported to be effective …
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Hot corrosion behaviour of new candidates for thermal barrier coatings application in turbine simulated environments
… used gas turbine engines. The current material of choice (YSZ) degrades when it contacts with impurities arise from low quality fuels such vanadium and sulfur. YSZ cannot be used in temperature higher than 900˚C. Higher efficiency and performance of gas turbine engines will require a new …
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Synthesis, Structure and Properties of Mixed Metal Oxides: From Pyrochlores to Fluorites
… and Literature Review: Different families of oxide ion conductors and their applications are discussed. Experimental and Characterisation Methods: The synthetic methods and characterisation techniques used throughout this thesis are described. Synthesis, Structure and Transport Properties …
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DFT study of doped and functionalized fullerene based materials for lithium-ion battery applications
… implications. The crystal structure of these materials sets an upper bound on the amount of lithium they can intercalate which limits the energy density of the device. Consequently, there is intense effort to develop novel and better cathode materials. Carbon based materials present a …
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Enhancement In Electrochemical Performance Of Advanced Battery Electrodes Using Carbon- Nanomaterial Composites
… low electronic conductivity (~10-9 S/cm) of LiFePO4 leads to high impedance, low capacity and low rate capability. To overcome this bottleneck, we have developed multiple approaches to improve the conductivity of LiFePO4. Motivated by the outstanding electronic and mechanical properties as …
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High-field SANS studies of the vortex lattice in YBCO
… presented the first high-field structural study of the vortex lattice in YBa\(_2\)Cu\(_3\)O\(_7\). Small-angle neutron scattering was used to deduce the configuration of vortices in a twinned sample of YBa\(_2\)Cu\(_3\)O\(_7\) over the field range 1–11T applied parallel to the crystal c-axis. The …
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Doping Studies of Frustrated Magnets
Doping nonmagnetic materials is known as an effective way of investigating the properties of frustrated magnets. LiCuSbO4 is one of the simplest quasi-one dimensional spin-1/2 magnets which can be modelled with ferromagnetic(FM) nearest neighbour and antiferromagnetic (AFM) next nearest neighbour …
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Magnetic Characterisation of Nanostructured Magnetic Systems Using SQUID Magnetometry
… tool to investigate the magnetic behaviour of a number of materials on the bulk, nano- and atomic scale. In particular magnetic characterization was conducted on a selection of doped lanthanum manganate (LMO)magnetic nanoparticles (MNPs), a family of lanthanide ionic liquids, and finally on …
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Effect of grain structure and doping on the mechanical properties of polysilicon thin films for MEMS
… applications could be engineered by modification of the material microstructure. Such advances require detailed experimental studies and quantitative understanding of the convoluted effects of the processing methods on the ensuing mechanical properties. This dissertation investigated the role of …