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Full-Text Articles in Physical Sciences and Mathematics
Photo-Induced Current Measurements In Chlamydomonas Cell Suspensions, Collin D. Capano
Photo-Induced Current Measurements In Chlamydomonas Cell Suspensions, Collin D. Capano
Honors Capstone Projects - All
In order to fully understand the principles behind phototaxis in flagellate algae, it is necessary to measure the electric currents these cells create when processing light stimuli. Many different techniques have been developed to do this. One of these techniques, measuring from cell suspensions, has a number of advantages over the others that makes it highly desirable. However, the lab that first developed this method of recording did not describe the setup very well. The result is that in the thirteen years since it was first reported, only one other independent lab has been able to reproduce the results despite …
The Straggling Green's Function Method For Ion Transport, Steven Andrew Walker
The Straggling Green's Function Method For Ion Transport, Steven Andrew Walker
Mathematics & Statistics Theses & Dissertations
For many years work has been conducted on developing a concise theory and method for HZE ion transport capable of being validated in the laboratory. Previous attempts have ignored dispersion and energy downshift associated with nuclear fragmentation and energy and range straggling. Here we present a Green's function approach to ion transport that incorporates these missing elements. This work forms the basis for a new version of GRNTRN, a Green's function transport code. Comparisons of GRNTRN predictions and laboratory results for an 56Fe ion beam with average energy at the target of one GeV/amu or more are presented for …
Characterizing A Neutron Energy Spectrum Using A "Forward Edge" Neutron Time-Of-Flight Spectroscopy Technique, Jeffrey S. Spear
Characterizing A Neutron Energy Spectrum Using A "Forward Edge" Neutron Time-Of-Flight Spectroscopy Technique, Jeffrey S. Spear
Theses and Dissertations
A Fermi-style thermal neutron disc chopper was designed, constructed, and calibrated in conjunction with a boron-loaded organic scintillator for use in creating a forward edge neutron time-of-flight spectroscopy technique. The forward edge neutron time-of-flight spectroscopy technique inferred the characteristics of a neutron energy spectrum. The system analyzed the spectrum of a moderated and unmoderated PuBe source with the aid of a MATLAB code. Through the use of pulse shape analysis techniques and energy spectroscopy the thermal neutron capture event was identified and isolated. Data analysis provided positive feedback in the disc chopper's ability to partially attenuate higher energy neutrons in …
Deep Level Defects In Electron-Irradiated Aluminum Gallium Nitride Grown By Molecular Beam Epitaxy, Michael R. Hogsed
Deep Level Defects In Electron-Irradiated Aluminum Gallium Nitride Grown By Molecular Beam Epitaxy, Michael R. Hogsed
Theses and Dissertations
Aluminum gallium nitride (AlGaN)-based devices are attractive candidates for integration into future Air Force communication and sensor platforms, including those that must operate in harsh radiation environments. In this study, the electrical and optical properties of 1.0 MeV electron irradiated n-AlxGa1-xN are characterized for aluminum mole fraction x = 0.0 to 0.3 using deep level transient spectroscopy (DLTS), temperature-dependent Hall, and cathodoluminescence (CL) measurements. Following irradiation of the AlGaN, it is found that four different electron traps are created, having energy levels within 0.4 eV below the conduction band edge. Three of these traps correspond to …
Classification Of Battlespace Detonations From Temporally Resolved Mutli-Band Imagery And Mid-Infrared Spectra, Anthony N. Dills
Classification Of Battlespace Detonations From Temporally Resolved Mutli-Band Imagery And Mid-Infrared Spectra, Anthony N. Dills
Theses and Dissertations
The classification of battlespace detonations, specifically the determination of munitions type and size using temporal and spectral features, has been studied using near-infrared (NIR) and multi-color visible wavelength imagers. Key features from the time dependence of fireball size are identified for discriminating various types and sizes of detonation flashes. The five classes include three weights of trinitrotoluene (TNT) and two weights of an enhanced mixture, all of which are uncased and detonated with 10% C4. Using Fisher linear discriminant techniques, features are projected onto a line such that the projected points are maximally clustered for the different classes of detonations. …
Detection Of Bacillus Spores By Aptamer Selectivity Using Atomic Force Microscopy, Nina M. Houtkooper
Detection Of Bacillus Spores By Aptamer Selectivity Using Atomic Force Microscopy, Nina M. Houtkooper
Theses and Dissertations
The anthrax attack of Oct 2001 demonstrates the need for a rapid detector for spores of Bacillus anthracis (BA). Current technology requires cultures of BA to be grown for 24 hours. Using aptamers, a type of nucleic acid ligand selective for a target molecule, to select BA spores for measurement without culturing is a possible solution for quicker detection. An aptamer having a specially selected structure is expected to selectively bind to the surface of its target spore, separating it from other material. An atomic force microscopy (AFM) method was developed to test this selectivity. Aptamers having structure selected to …
Optical Investigation Of Transition Metal Implanted Wide Band Gap Semiconductors, Brian P. Feller
Optical Investigation Of Transition Metal Implanted Wide Band Gap Semiconductors, Brian P. Feller
Theses and Dissertations
Thin films of GaN, Al0.1Ga0.9N, and ZnO were implanted with Cr, Mn, and nickel Ni to produce dilute magnetic semiconductors. Optical and magnetic techniques were used to evaluate crystal structure restoration and coercive field strength as a function of implant species and annealing temperature. Maximum crystal restoration was obtained for Al0.1Ga0.9N after annealing at 675 °C; for Cr implanted p-GaN after annealing at 750 °C; for Mn or Ni implanted p-GaN after annealing at 675 °C; for Cr implanted ZnO after annealing at 700 °C; for Mn implanted ZnO after annealing at …
Quantum Monte Carlo Method For Boson Ground States: Application To Trapped Bosons With Attractive And Repulsive Interactions, Wirawan Purwanto
Quantum Monte Carlo Method For Boson Ground States: Application To Trapped Bosons With Attractive And Repulsive Interactions, Wirawan Purwanto
Dissertations, Theses, and Masters Projects
We formulate a quantum Monte Carlo (QMC) method for calculating the ground state of many-boson systems. The method is based on a field-theoretical approach, and is closely related to existing fermion auxiliary-field QMC methods which are applied in several fields of physics. The ground-state projection is implemented as a branching random walk in the space of permanents consisting of identical single-particle orbitals. Any single-particle basis can be used, and the method is in principle exact. We apply this method to an atomic Bose gas, where the atoms interact via an attractive or repulsive contact two-body potential parametrized by the s-wave …