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Theses/Dissertations

2014

Articles 1 - 6 of 6

Full-Text Articles in Physics

Surface Effects On Critical Dimensions Of Ferromagnetic Nanoparticles, Vartika Chaudhary Jan 2014

Surface Effects On Critical Dimensions Of Ferromagnetic Nanoparticles, Vartika Chaudhary

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This work studies surface effects on the critical dimensions of ferromagnetic nanoparticles. Iron nanoparticles with different mean diameters from 5.9 nm to 21.4 nm used in this research were prepared by thermal decomposition of iron pentacarbonyl in the presence of oleic acid/octyl ether at Cambridge University, United Kingdom. Heating response of these ferromagnetic nanoparticles suspended in water were measured experimentally during which same amount of iron nanoparticles and di-ionized water were irradiated by an alternating magnetic field and the increase in temperature of these samples was measured. Heating performance of nanoparticles was described in terms of Specific Absorption Rate (SAR) …

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Chemical Analysis Of Exhaled Breath By Means Of Terahertz Rotational Spectroscopy, Tianle Guo Jan 2014

Chemical Analysis Of Exhaled Breath By Means Of Terahertz Rotational Spectroscopy, Tianle Guo

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Terahertz spectroscopy, due to the high sensitivity and specificity that it affords, has been incorporated in many fields to aid in the chemical analysis of gases. One potential application is to detect bio-markers in human breath for early diagnosis. Our current aim of our research is to establish a relationship between several chemicals and the glucose levels from human exhaled breath. 20 chemical including Acetone, Carbon monoxide (CO), Methanol were studied. Volunteers' breath samples were processed through a pre-concentration system before being injected into the spectrometer. Initially, a commercial preconcentration system, Entech 7100A, was used. However, due to the limitations …

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Thermal Properties Of Magnetic Nanoparticles In External Ac Magnetic Field, Anna Beata Lukawska Jan 2014

Thermal Properties Of Magnetic Nanoparticles In External Ac Magnetic Field, Anna Beata Lukawska

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This work studies thermal properties of magnetic nanoparticles in an external ac magnetic field. Dried iron and cobalt nanoparticles were prepared by thermal decomposition of iron pentacarbonyl (Fe(CO)5) and dicobalt octacarbonyl (Co2(CO)8), triscobalt nona(carbonyl)chloride (Co3(CO)9Cl), or tetracaobalt dodecacarbonyl (Co4(CO)12) [1]. The samples had different mean diameters: 5.6 - 21.4 nm for iron and 6.5 - 19.4 nm for cobalt. Each sample was exposed to ac magnetic field and the increase in temperature of the sample was measured. Results were analyzed to find the critical diameters for the transitions from multi-domain to single-domain and from single-domain to superparamagnetic regime. The nanoparticles …

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Thin Film Growth Of Dielectric Materials By Pulsed Laser Deposition, Jason Christopher Anders Jan 2014

Thin Film Growth Of Dielectric Materials By Pulsed Laser Deposition, Jason Christopher Anders

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Thin films of SryCa1-yZr1-xTixO3 (SCZT) with x = 0.8, y = 0.01, CaHf1-xTixO3 (CHT) with x = 0.8, and xBiScO3 - (1-x) BaTiO3 with x = 0.36 (BSBT(36/64)) showing a high permittivity are useful both in capacitor applications. These dielectric thin films with a SrRuO3 (SRO) conductive bottom electrodes were prepared by using pulsed laser deposition on <100< La0.3Sr0.7Al0.65Ta0.35O3 (LSAT) single crystal substrates. In a search of optimal conditions to achieve epitaxially grown SCZT, CHT, …

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Ultraviolet Rayleigh Scatter Imaging For Spatial Temperature Profiles In Atmospheric Microdischarges, James E. Caplinger Jan 2014

Ultraviolet Rayleigh Scatter Imaging For Spatial Temperature Profiles In Atmospheric Microdischarges, James E. Caplinger

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Spatially resolved temperature measurements within a microdischarge in atmospheric pressure air have been conducted using Rayleigh scattering of a pulsed ultraviolet laser. Scattering intensity images were used to generate a radial profile of translational temperature, with the analysis based on the ideal gas inverse relationship of temperature and gas density. Rayleigh scattering results were compared to standard optical emission spectral analyses of N2(C3Πu - B3Πg) bands, where the calculated rotational temperatures from emission were in reasonable agreement with the Rayleigh translational temperature profiles.

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Curie Temperature Measurement Of Ferromagnetic Nanoparticles By Using Calorimetry, Xing Zhao Jan 2014

Curie Temperature Measurement Of Ferromagnetic Nanoparticles By Using Calorimetry, Xing Zhao

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This Thesis studies the relationship between diameter (size) of ferromagnetic nanoparticles and Curie temperature. Iron nanoparticles with different diameters from 5.9 nm to 21.4 nm were prepared by thermal decomposition of iron pentacarbonyl in the presence of oleic acid/octyl ether at Cambridge University, United Kingdom. Heating response of these ferromagnetic nanoparticles suspended in water were measured experimentally during which the same amount of iron nanoparticles and di-ionized water were subjected to an alternating magnetic field and the increase in temperature of these samples was measured. Heating performance of nanoparticles was described by Specific Absorption Rate (SAR). Heating and cooling rate …

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