Physics Commons^™

Tuning Electronic Correlation With Pressure, Gilberto Fernandes Lopes Fabbris

Arts & Sciences Electronic Theses and Dissertations

Strongly correlated electron systems display some of the most exotic ground states in condensed matter. In this thesis high pressure is used to tune the degree of electron correlations in systems of current interest. Their electronic and structural properties were investigated at high pressure using x-ray spectroscopy and scattering as well as transport techniques in a diamond anvil cell. The interplay between short- and long-range structural order, one-dimensional charge ordering, and superconductivity was studied in La_1.875Ba_0.125CuO₄. At ambient pressure, this material displays charge ordering at the onset of a low temperature structural phase transition, …

Comparison Of Conventional And Bayesian Analysis For The Ultrasonic Characterization Of Cancellous Bone, Amber Groopman

Arts & Sciences Electronic Theses and Dissertations

This dissertation investigates the physics underlying the propagation of ultrasonic waves in cancellous bone. Although quantitative ultrasound has the potential to evaluate bone quality even better than the current gold standard X-ray based modality, its clinical utility has been hampered by the incomplete understanding of the mechanisms governing the interaction between ultrasound and bone. Therefore, studies that extend the understanding of the fundamental physics of the relationship between ultrasound and trabecular bone tissue may result in improved clinical capabilities.

Ultrasonic measurements were carried out on excised human calcaneal specimens in order to study the effects of overlapping fast and slow …

X-Ray Polarimetry With X-Calibur, Qingzhen Guo

Arts & Sciences Electronic Theses and Dissertations

ABSTRACT

X-Ray Polarimetry with X-Calibur

by

Qingzhen Guo

Doctor of Philosophy in Physics, Washington University in St. Louis,

September, 2014. Professor Henric Krawczynski, Chair

X-ray polarimetry is a prime tool to investigate the unexplored compact sources and to provide crucial information that other techniques can not produce. By measuring the degree and orientation of the polarization of radiation from a cosmic source, unique inferences about the morphology and the magnetic field structure can be made.

Krawczysnki's group at Washington University is working on a uniquely sensitive scattering polarimeter, X-Calibur, to be used in the focal plane of a focusing X-ray …

Optical Resonators And Fiber Tapers As Transducers For Detection Of Nanoparticles And Bio-Molecules, Huzeyfe Yilmaz

McKelvey School of Engineering Theses & Dissertations

In recent years, detection of biological interactions on single molecule level has aspired many researchers to investigate several optical, chemical, electrical and mechanical sensing tools. Among these tools, toroidal optical resonators lead the way in detection of the smallest particle/molecule with the real time measurements. In this work, bio-sensing capabilities of toroidal optical resonators are investigated. Bio-sensing is realized via measuring the analyte-antigen interaction while the antigen is immobilized through a novel functionalization method.

Not long ago, detection of single nanoparticles using optical resonators has been accomplished however the need for cost-effective and practical transducers demands simpler tools. A tapered …