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Full-Text Articles in Physics
Parity-Violation In Elastic Electron Scattering: A First Measurement Of The Parity-Violating Asymmetry At Q2 = 0.631 (Gev/C)2 At Backward Angle, Stephanie L. Bailey
Parity-Violation In Elastic Electron Scattering: A First Measurement Of The Parity-Violating Asymmetry At Q2 = 0.631 (Gev/C)2 At Backward Angle, Stephanie L. Bailey
Dissertations, Theses, and Masters Projects
The goal of Experiment E04-115 (the G0 backward angle measurement) at Jefferson Lab is to investigate the contributions of strange quarks to the fundamental properties of the nucleon. The experiment measures parity-violating asymmetries in elastic electron scattering off hydrogen and quasielastic electron scattering off deuterium at backward angles at Q2 = 0.631 (GeV/c)2 and Q 2 = 0.232 (GeV/c)2. The backward angle measurement represents the second phase of the G0 experiment. The first phase, Experiment E00-006 (the G0 forward angle experiment), measured parity-violating asymmetries in elastic electron scattering off hydrogen at forward angles over a Q 2 range of 0.1-1.0 …
Fluorescence Imaging Study Of Free And Impinging Supersonic Jets: Jet Structure And Turbulent Transition, Jennifer Ann Inman
Fluorescence Imaging Study Of Free And Impinging Supersonic Jets: Jet Structure And Turbulent Transition, Jennifer Ann Inman
Dissertations, Theses, and Masters Projects
A series of experiments into the behavior of underexpanded jet flows has been conducted at NASA Langley Research Center. This work was conducted in support of the Return to Flight effort following the loss of the Columbia. The tests involved simulating flow through a hypothetical breach in the leading edge of the Space Shuttle Orbiter along its reentry trajectory, with the goal of generating a data set with which other researchers can test and validate computational modeling tools. Two nozzles supplied with high-pressure gas were used to generate axisymmetric underexpanded jets exhausting into a low-pressure chamber. These nozzles had exit …
First-Principles Calculations Of Electric Field Gradients In Complex Perovskites, Dandan Mao
First-Principles Calculations Of Electric Field Gradients In Complex Perovskites, Dandan Mao
Dissertations, Theses, and Masters Projects
Various experimental and theoretical work indicate that the local structure and chemical ordering play a crucial role in the different physical behaviors of lead-based complex ferroelectrics with the ABO 3 perovskite structure. First-principles linearized augmented plane wave (LAPW) with the local orbital extension method within local density approximation (LDA) are performed on structural models of Pb(Zr1/2Ti1/2 )O3 (PZT), Pb(Sc1/2Ta1/2)O3 (PST), Pb(Sc2/3W1/3)O3 (PSW), and Pb(Mg 1/3Nb2/3)O3 (PMN) to calculate electric field gradients (EFGs). In order to simulate these disordered alloys, various structural models were constructed with different imposed chemical orderings and symmetries. Calculations were carried out as a function of B-site …
Magneto-Optical Imaging Of Superconducting Mgb2 Thin Films, Stephanie Maria Hummert
Magneto-Optical Imaging Of Superconducting Mgb2 Thin Films, Stephanie Maria Hummert
Dissertations, Theses, and Masters Projects
No abstract provided.
Measurement Of The Branching Fraction For The Decay Neutral Kaon(Long) Going To Pion-Antipion-Positron-Electron In The High M(Pi-Pi) Invariant Mass Region, Joshua J. Moss
Dissertations, Theses, and Masters Projects
A measurement of the branching fraction for the rare decay K0L → pi+pi-e +e- was performed using data collected from experiment E871 which ran at the AGS of Brookhaven National Laboratory. Analysis of the data revealed 27.7 +/- 7.4 signal events in the signal region, 0.4905 GeV < Mpipiee < 0.505 GeV together with 13.3 +/- 3.7 background events. The branching fractions of ( 8.5+/-2.3stat +/-1.0sys ) x 10-6 using the phenomenological model acceptance and ( 2.3+/-0.6stat +/-0.3sys ) x 10-6 using the chiral perturbation model represent the first measurements for K0L → pi+pi-e +e- in the dipion invariant mass region 0.475 GeV < Mpipi < 0.497 GeV. These results support the prediction of chiral perturbation theory rather than that of the phenomenological model.
Magnetization Dynamics And Anisotropy In Ferromagnetic/Antiferromagnetic Ni/Nio Bilayers, Andreas Petersen
Magnetization Dynamics And Anisotropy In Ferromagnetic/Antiferromagnetic Ni/Nio Bilayers, Andreas Petersen
Dissertations, Theses, and Masters Projects
No abstract provided.
Spatial Beam Shaping Of High-Power Ultrashort Laser Pulses, Shuyan Zhang
Spatial Beam Shaping Of High-Power Ultrashort Laser Pulses, Shuyan Zhang
Dissertations, Theses, and Masters Projects
This thesis presents both theoretical and experimental studies of a diffractive beam shaping system for ultrashort high-power laser pulses.;A theoretical model is developed to simulate the reshaped intensity profiles for a 100-fs pulse with various energy levels. Both temporal evolution and spatial intensity distribution of the pulse at the target plane of the beam shaping system are calculated. Numerical simulation shows that after passing through the beam shaping system, the pulse front is significantly curved due to the propagation time delay, and the pulse duration time through the target plane is broadened because of the group velocity dispersion. However, for …
Effects Of Molecular Motion On Deuteron Magic Angle Spinning Nmr Spectra, Yuanyuan Huang
Effects Of Molecular Motion On Deuteron Magic Angle Spinning Nmr Spectra, Yuanyuan Huang
Dissertations, Theses, and Masters Projects
Solid state deuteron NMR experiments, especially magic angle spinning (MAS) and off-magic angle spinning (OMAS), are developed to explore dynamical systems. A theoretical discussion of interactions relevant for spin-1 nuclei is presented. Practical aspects of MAS/OMAS experiments are described an detail. The dominant quadrupolar coupling interaction in deuteron NMR has been simulated and the effects of multiple-frame molecular motions on MAS/OMAS spectra are taken into account in this calculation. Effects of chemical shift anisotropy are also simulated, and shown to be small under conditions of rapid sample spinning.;Two numerical methods, direct integration and an efficient simulation routine based on Floquet …