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Hard-Sphere-Like Dynamics In Highly Concentrated Alpha-Crystallin Suspensions, Preeti Vodnala, Laurence Lurio, Michael C. Vega, Elizabeth Gaillard Feb 2018

Hard-Sphere-Like Dynamics In Highly Concentrated Alpha-Crystallin Suspensions, Preeti Vodnala, Laurence Lurio, Michael C. Vega, Elizabeth Gaillard

Faculty Peer-Reviewed Publications

The dynamics of concentrated suspensions of the eye-lens protein alpha crystallin have been measured using x-ray photon correlation spectroscopy. Measurements were made at wave vectors corresponding to the first peak in the hard-sphere structure factor and volume fractions close to the critical volume fraction for the glass transition. Langevin dynamics simulations were also performed in parallel to the experiments. The intermediate scattering function f(q,τ) could be fit using a stretched exponential decay for both experiments and numerical simulations. The measured relaxation times show good agreement with simulations for polydisperse hard-sphere colloids.


Phase-Space Manipulations Of Electron Beams For X-Ray Free-Electron Lasers And Inverse Compton Scattering Sources., Alexander V. Malyzhenkov Jan 2018

Phase-Space Manipulations Of Electron Beams For X-Ray Free-Electron Lasers And Inverse Compton Scattering Sources., Alexander V. Malyzhenkov

Graduate Research Theses & Dissertations

This dissertation describes advanced techniques of phase space manipulations of the electron beam for improving performance and efficiency of high brightness X-ray light sources based on the free-electron Laser (FEL) and inverse-Compton scattering (ICS) processes. In particular, it first discusses a novel bunch-compression scheme based on a double transverse-to-longitudinal phase-space exchanger -- dubbed emittance exchanger (EEX) -- separated by a demagnifying transverse-optics system. While the outline of the scheme is quite sophisticated, the basic physics behind it is quite straight-forward. The benefits and disadvantages of these scheme are compared to the conventional approach of compressing a bunch using a magnetic …


Discovery And Study Of Single-Phase And Single-Ion Manganese Perovskite Multiferroics, Kamal Chapagain Jan 2018

Discovery And Study Of Single-Phase And Single-Ion Manganese Perovskite Multiferroics, Kamal Chapagain

Graduate Research Theses & Dissertations

Multiferroic materials having unusual properties of simultaneous presence of ferroelectricity (FE) and magnetism, such that FE can be controlled by magnetic field and magnetization by electric field have attracted interest due to their promising applications in electrically controllable microwave elements, magnetic field sensors, and possibly in spintronics. In this dissertation, the single phase and single ion multiferroic properties of the ceramic oxide antiferromagnets (AFM) Sr1-xBax Mn1-yTiyO3 with perovskite structure are discussed. These compounds were designed and developed in our laboratory by understanding critical parameters controlling FE and magnetic properties, advancing the synthesis processes, studying the structural behavior and intricate transitions, …


Diffuse Scattering And Local Order In Lead-Based Relaxor Ferroelectrics, Matthew J. Krogstad Jan 2018

Diffuse Scattering And Local Order In Lead-Based Relaxor Ferroelectrics, Matthew J. Krogstad

Graduate Research Theses & Dissertations

Relaxor ferroelectrics are characterized by their dielectric permittivity, and some of these materials display outstanding electromechanical coupling, a property that makes them useful in applications from sonar and ultrasound to precision actuators. However, there is a surprising lack of consensus regarding the local structure of these materials and how it relates to their useful bulk properties. A common feature of many proposed mechanisms is the importance of short-range order differing from the long-range symmetry of the material. Such a difference between short-range and long-range order makes these materials ideal candidates for study via diffuse scattering, a technique sensitive to differences …