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Full-Text Articles in Physics
Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves
Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves
Graduate Theses, Dissertations, and Problem Reports
Having been theorized in 1947, it was not until 2004 that graphene was first isolated. In the years since its isolation, graphene has been the subject of intense, world-wide study due to its incredibly diverse array of useful properties. Even though many billions of dollars have been spent on its development, graphene has yet to break out of the laboratory and penetrate mainstream industrial applications markets. This is because graphene faces a ‘grand challenge.’ Simply put, there is currently no method of manufacturing high-quality graphene on the industrial scale. This grand challenge looms particularly large for electronic applications where the …
Light Scattering In Diffraction Limit Infrared Imaging, Ghazal Azarfar
Light Scattering In Diffraction Limit Infrared Imaging, Ghazal Azarfar
Theses and Dissertations
Fourier Transform Infrared (FTIR) microspectroscopy is a noninvasive technique for chemical imaging of micrometer size samples. Employing an infrared microscope, an infrared source and FTIR spectrometer coupled to a microscope with an array of detectors (128 x 128 detectors), enables collecting combined spectral and spatial information simultaneously. Wavelength dependent images are collected, that reveal biochemical signatures of disease pathology and cell cycle. Single cell biochemistry can be evaluated with this technique, since the wavelength of light is comparable to the size of the objects of interest, which leads to additional spectral and spatial effects disturb biological signatures and can confound …
Multispectral Identification Array, Zachary D. Eagan
Multispectral Identification Array, Zachary D. Eagan
Computer Engineering
The Multispectral Identification Array is a device for taking full image spectroscopy data via the illumination of a subject with sixty-four unique spectra. The array combines images under the illumination spectra to produce an approximate reflectance graph for every pixel in a scene. Acquisition of an entire spectrum allows the array to differentiate objects based on surface material. Spectral graphs produced are highly approximate and should not be used to determine material properties, however the output is sufficiently consistent to allow differentiation and identification of previously sampled subjects. While not sufficiently advanced for use as a replacement to spectroscopy the …
Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc
Label-Free Raman Imaging To Monitor Breast Tumor Signatures, John Ciubuc
Open Access Theses & Dissertations
Methods built on Raman spectroscopy have shown major potential in describing and discriminating between malignant and benign specimens. Accurate, real-time medical diagnosis benefits in substantial improvements through this vibrational optical method. Not only is acquisition of data possible in milliseconds and analysis in minutes, Raman allows concurrent detection and monitoring of all biological components. Besides validating a significant Raman signature distinction between non-tumorigenic (MCF-10A) and tumorigenic (MCF-7) breast epithelial cells, this study reveals a label-free method to assess overexpression of epidermal growth factor receptors (EGFR) in tumor cells. EGFR overexpression sires Raman features associated with phosphorylated threonine and serine, and …
Pulsed Inductive Plasma Studies By Spectroscopy And Internal Probe Methods, Warner C. Meeks
Pulsed Inductive Plasma Studies By Spectroscopy And Internal Probe Methods, Warner C. Meeks
Doctoral Dissertations
The broad effort of the Missouri Plasmoid Experiment is to elucidate the energy conversion processes in a pulsed inductive discharge due to the presence of plasma. The test article is a 440 to 490 kHz theta-pinch (or solenoidal) geometry coil with a stored energy of around 80 joules. In this work experimental hydrogen, helium, argon and xenon data at back-fill pressures of 10 to 100 mTorr (1.3 to 133.3 Pa) are obtained and interpreted. Spectral and internal probe studies were performed on MPX Mk.I and Mk.II devices, respectively. IR spectra were acquired in the Mk.I device for argon and xenon. …
Optimization Of Plasmon Decay Through Scattering And Hot Electron Transfer, Drew Dejarnette
Optimization Of Plasmon Decay Through Scattering And Hot Electron Transfer, Drew Dejarnette
Graduate Theses and Dissertations
Light incident on metal nanoparticles induce localized surface oscillations of conductive electrons, called plasmons, which is a means to control and manipulate light. Excited plasmons decay as either thermal energy as absorbed phonons or electromagnetic energy as scattered photons. An additional decay pathway for plasmons can exist for gold nanoparticles situated on graphene. Excited plasmons can decay directly to the graphene as through hot electron transfer. This dissertation begins by computational analysis of plasmon resonance energy and bandwidth as a function of particle size, shape, and dielectric environment in addition to diffractive coupled in lattices creating a Fano resonance. With …
Random Transformations Of Optical Fields And Applications, Thomas Kohlgraf-Owens
Random Transformations Of Optical Fields And Applications, Thomas Kohlgraf-Owens
Electronic Theses and Dissertations
The interaction of optical waves with material systems often results in complex, seemingly random fields. Because the fluctuations of such fields are typically difficult to analyze, they are regarded as noise to be suppressed. Nevertheless, in many cases the fluctuations of the field result from a linear and deterministic, albeit complicated, interaction between the optical field and the scattering system. As a result, linear systems theory (LST) can be used to frame the scattering problem and highlight situations in which useful information can be extracted from the fluctuations of the scattered field. Three fundamental problems can be posed in LST …
Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler
Poincare Recurrence And Spectral Cascades In Three-Dimensional Quantum Turbulence, George Vahala, Jeffrey Yepez, Linda L. Vahala, Min Soe, Bo Zhang, Sean Ziegeler
Electrical & Computer Engineering Faculty Publications
The time evolution of the ground state wave function of a zero-temperature Bose-Einstein condensate (BEC) gas is well described by the Hamiltonian Gross-Pitaevskii (GP) equation. Using a set of appropriately interleaved unitary collision-stream operators, a qubit lattice gas algorithm is devised, which on taking moments, recovers the Gross-Pitaevskii (GP) equation under diffusion ordering (time scales as length2). Unexpectedly, there is a class of initial states whose Poincaré recurrence time is extremely short and which, as the grid resolution is increased, scales with diffusion ordering (and not as length3). The spectral results of J. Yepez et al. …
Superfluid Turbulence From Quantum Kelvin Wave To Classical Kolmogorov Cascades, Jeffrey Yepez, George Vahala, Linda L. Vahala, Min Soe
Superfluid Turbulence From Quantum Kelvin Wave To Classical Kolmogorov Cascades, Jeffrey Yepez, George Vahala, Linda L. Vahala, Min Soe
Electrical & Computer Engineering Faculty Publications
The main topological feature of a superfluid is a quantum vortex with an identifiable inner and outer radius. A novel unitary quantum lattice gas algorithm is used to simulate quantum turbulence of a Bose-Einstein condensate superfluid described by the Gross-Pitaevskii equation on grids up to 57603. For the first time, an accurate power-law scaling for the quantum Kelvin wave cascade is determined: k-3. The incompressible kinetic energy spectrum exhibits very distinct power-law spectra in 3 ranges of k space: a classical Kolmogorov k-(5/3) spectrum at scales greater than the outer radius of individual quantum vortex …
Molecular Structure-Nonlinear Optical Property Relationships For A Series Of Polymethine And Squaraine Molecules, Jie Fu
Electronic Theses and Dissertations
This dissertation reports on the investigation of the relationships between molecular structure and two-photon absorption (2PA) properties for a series of polymethine and squaraine molecules. Current and emerging applications exploiting the quadratic dependence upon laser intensity, such as two-photon fluorescence imaging, three-dimensional microfabrication, optical data storage and optical limiting, have motivated researchers to find novel materials exhibiting strong 2PA. Organic materials are promising candidates because their linear and nonlinear optical properties can be optimized for applications by changing their structures through molecular engineering. Polymethine and squaraine dyes are particularly interesting because they are fluorescent and showing large 2PA. We used …