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Full-Text Articles in Physical Sciences and Mathematics
Analysis And Implementation Of The Maximum Likelihood Expectation Maximization Algorithm For Find, Angus Boyd Jameson
Analysis And Implementation Of The Maximum Likelihood Expectation Maximization Algorithm For Find, Angus Boyd Jameson
Student Research Projects
This thesis presents an organized explanation and breakdown of the Maximum Likelihood Expectation Maximization image reconstruction algorithm. This background research was used to develop a means of implementing the algorithm into the imaging code for UNH's Field Deployable Imaging Neutron Detector to improve its ability to resolve complex neutron sources. This thesis provides an overview for this implementation scheme, and include the results of a couple of reconstruction tests for the algorithm. A discussion is given on the current state of the algorithm and its integration with the neutron detector system, and suggestions are given for how the work and …
Decreasing Uncertainty In Nuclear Magnetic Resonance Measurements Through The Application Of Pappus Chains, Ryan Williams
Decreasing Uncertainty In Nuclear Magnetic Resonance Measurements Through The Application Of Pappus Chains, Ryan Williams
Honors Theses and Capstones
To make further advancements in nuclear polarization, the Dynamic Nuclear Polarization Group at the University of New Hampshire requires an accurate measurement of the polarization of their materials. Through a non-traditional method of data analysis, the uncertainty in this polarization measurement via Nuclear Magnetic Resonance (NMR) was reduced. To extract the polarization, we measure an NMR signal through the real impedance of our circuitry, whose area is proportional to the polarization. However, our signal size depends on how in-tune our circuitry is with a specific frequency, with the signal growing smaller the less in-tune it becomes. A new method of …
Quantifying Electron Precipitation In The Van Allen Radiation Belts, Timothy Raeder
Quantifying Electron Precipitation In The Van Allen Radiation Belts, Timothy Raeder
Honors Theses and Capstones
The spatial and temporal distribution of high energy electron precipitation from the Van Allen radiation belts is not currently well-understood. The FIREBIRD-II mission (2015-present) and the Van Allen Probes (2012-2019) provide a unique opportunity to examine the behaviors and drivers of high energy electron precipitation. This study quantifies electron precipitation observed by FIREBIRD-II as a function of radial distance (L-shell), magnetic local time (MLT), hemisphere, and geomagnetic indices (Kp). Electron precipitation was observed to peak at L-shell 4.5-5. Regions of elevated electron precipitation were identified at L-shell 4-6 at dawn (MLT 6-9) and dusk (MLT 15-21). Hemisphere filtering indicated very …
Investigating The Time Scales Of Electromechanical Motion In Graphene Drumheads Using Pump-Probe Spectroscopy With Stm, Alana P. Gudinas
Investigating The Time Scales Of Electromechanical Motion In Graphene Drumheads Using Pump-Probe Spectroscopy With Stm, Alana P. Gudinas
Honors Theses and Capstones
Scanning tunneling microscopy (STM) has transformed the field of condensed matter physics over the past few decades, allowing scientists to image materials at the atmomic scale, manipulate individual atoms, and probe electronic states on the surface of materials. In recent years, there have been numerous developments to introduce time-resolved measurements to STM in order to probe atomic-scale dynamic processes and combine spatial and temporal resolution. Advances like THz-STM setups achieve femtosecond resolution, but require complex external setups. All-electronic pump-probe spectroscopy for STM (directly analogous to optical pump-probe spectroscopy) has been pioneered by Loth et al., and newer applications (Natterer et …