Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, 2020 Chapman University
Hot Electron Chemistry On Bimetallic Plasmonic Nanoparticles, Bryn E. Merrill, Bingjie Zhang, Jerry Larue
Student Scholar Symposium Abstracts and Posters
Catalysis provides pathways for efficient and selective chemical reactions through the lowering of energy barriers for desired products. Gold nanoparticles (AuNP) show excellent promise as plasmonic catalysts. Localized surface plasmon resonances are oscillations of the electron bath at the surface of a nanoparticle that generate energetically intense electric fields and rapidly decay into energetically excited electrons. The excited electrons have the potential to destabilize strongly bound oxygen atoms through occupation of accessible anti-bonding orbitals. Tuning the anti-bonding orbitals to make them accessible for occupancy will be achieved by coating the AuNP in a thin layer of another transition metal, such ...
240— Target Characterization Using Rutherford Backscattering Spectroscopy, 2020 SUNY Geneseo
240— Target Characterization Using Rutherford Backscattering Spectroscopy, Matthew G. Klein, Anthony C. Cooper, Jovahn A. Roumell
Rutherford backscattering spectroscopy (RBS) is a non-destructive ion-beam analytical technique that is used to determine properties of a target such as thickness, areal density, and elemental composition. This scattering is the result of Coulomb forces between the target atoms and the incident particle. The energy spectrum of the scattered ions depends on the atomic number of the target atoms as well as the target thickness.
1d Fluid Model Of Rf-Excited Cold Atmospheric Plasmas In Helium With Air Gas Impurities, 2020 Old Dominion University
1d Fluid Model Of Rf-Excited Cold Atmospheric Plasmas In Helium With Air Gas Impurities, Yifan Liu, Dingxin Liu, Jishen Zhang, Bowen Sun, Aijun Yang, Michael G. Kong
Cold atmospheric plasmas (CAPs) in helium with air gas impurities (HeþAir for abbreviation) compromise the discharge stability of helium and the chemical reactivity of air, having great prospects for various applications such as plasma biomedicine. However, different kinds of reactive species are produced in HeþAir CAPs but only a few of them could be measured, and the plasma chemistry is so complex that the reported simulation models are simplified to a large extent, such as neglecting the space variation of CAPs by using a 0D model. As a result, much remains unknown for HeþAir CAPs, which hinders the development of ...
Si Nanocrystal Synthesis Via Double Implantation And Variable Implantation, 2020 The University of Western Ontario
Si Nanocrystal Synthesis Via Double Implantation And Variable Implantation, James M. Gaudet
Electronic Thesis and Dissertation Repository
Silicon (Si) nanocrystals (nc) precipitated from silicon-implanted silicon oxide (SiO2) are of interest as a novel light source for illumination, biomedical applications, optical computing, etc. They have some advantages over conventional III-V compound semiconductor nanocrystals produced by colloidal synthesis. They are compatible with Si/SiO2 based semiconductor processing, are stable, non-toxic at point of synthesis and consumption, and their luminescence falls with the infrared transmission window of biological materials. Unfortunately, synthesis of Si-nc embedded SiO2 is uneconomical and is not as amenable to precise control of the size distribution of nanocrystals as is the case for III-V ...
Control Of Charged Particle Dynamics And Electron Power Absorption Dynamics Utilizing Voltage Waveform Tailoring In Capacitively Driven Radio-Frequency Plasmas, Steven W. Brandt
Graduate Theses, Dissertations, and Problem Reports
In this work, experimental measurements and analysis of numerical simulations are performed for capacitively coupled plasmas driven by tailored voltage waveforms under conditions which examine complicating factors present in industrial processes, including the influence of resonance effects, electronegative gases or gas mixtures, and plasma-surface interactions at a changing plasma-surface interface. Furthermore, the influence of different tailored voltage waveforms on the spatio-temporal electron power absorption, the generation of a DC self-bias, and on process relevant plasma parameters like ion energy distribution functions is investigated to provide a more complete understanding of the underlying fundamental plasma physics responsible for sustaining the discharge ...
Interpretations Of Bicoherence In Space & Lab Plasma Dynamics, 2020 West Virginia University
Interpretations Of Bicoherence In Space & Lab Plasma Dynamics, Gregory Allen Riggs
Graduate Theses, Dissertations, and Problem Reports
The application of bicoherence analysis to plasma research, particularly in non-linear, coupled-wave regimes, has thus far been significantly belied by poor resolution in time, and/or outright destruction of frequency information. Though the typical power spectrum cloaks the phase-coherency between frequencies, Fourier transforms of higher-order convolutions provide an n-dimensional spectrum which is adept at elucidating n-wave phase coherence. As such, this investigation focuses on the utility of the normalized bispectrum for detection of wave-wave coupling in general, with emphasis on distinct implications within the scope of non-linear plasma physics. Interpretations of bicoherent features are given for time series ...
Investigation Of Mnxni1-Xo Thin Films Using Pulsed Laser Deposition, 2020 Missouri State University
Investigation Of Mnxni1-Xo Thin Films Using Pulsed Laser Deposition, Md Ashif Anwar
MSU Graduate Theses
The exchange bias (EB) effect, especially in nanomaterials, is highly promising for use in antiferromagnet-based spintronics applications. NiO is a well known antiferromagnetic material with a high Néel temperature (525K) and can exhibit ferromagnetism/ ferrimagnetism by adding other magnetic transition elements. Our previous work has shown that the antiferromagnetic characteristics of conventional NiO insulating nanostructured material can be altered to have substantial ferrimagnetic characteristics by doping NiO with Mn or Co. Pulsed laser deposition (PLD) was used to grow heterostructures comprised of a nanostructured thin NiO film deposited on the surface of a MgO (100) and Al2O3 ...
A Review Of Ball Lightning Models, 2019 Georgia College and State University
A Review Of Ball Lightning Models, Amir Abdallah, Kyle Castleberry, Anyauna Spikes, Khadeem Coumarbatch, Joshua Ballard-Myer, Nick Palmer, Hasitha Mahabaduge
Georgia Journal of Science
Ball lightning is a natural phenomenon that occurs in the atmosphere. However due to its brevity and rarity, its occurrence is not well understood. Three models based on electromagnetic properties are discussed in this paper to explain the rare phenomenon of ball lightning. The first model incorporates the idea of electron bunching, electrons moving with different velocities. This creates a plasma bubble by recombining electrons with ionized gas to form plasma that is stabilized by a standing microwave. The second model explains the idea of streamers being tangled and linked in a magnetic field while stabilized by the conservation of ...
Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, 2019 The University of New Mexico
Experimental Testing Of A 3d-Printed Metamaterial Slow Wave Structure For High Power Microwave Generation, Antonio B. De Alleluia
Electrical and Computer Engineering ETDs
A metamaterial (MTM) high power microwave (HPM) vacuum electron device (VED) was developed using 3D printing technology. The specific geometric pattern of the source can produce both negative permittivity and permeability to interact with a relativistic electron beam. The electron beam is generated using a pulsed electron accelerator with a maximum energy of 700 keV and lasting approximately 16 ns. The design of this novel VED consists of a circular waveguide loaded with complementary split-ring resonators in a linear periodic arrangement in which the relativistic beam travels guided by a magnetic field. The electrons interact with the MTM producing electromagnetic ...
Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, 2019 Old Dominion University
Characterization Of Argon And Ar/Cl2 Plasmas Used For The Processing Of Niobium Superconducting Radio-Frequency Cavities, Jeremy J. Peshl
Physics Theses & Dissertations
The plasma processing of superconducting radio-frequency (SRF) cavities has shown significant promise as a complementary or possible replacement for the current wet etch processes. Empirical relationships between the user-controlled external parameters and the effectiveness of Reactive Ion Etching (RIE) for the removal of surface layers of bulk niobium have been previously established. However, a lack of a physical description of the etching discharge, particularly as the external parameters are varied, limits the development of this technology. A full understanding of how these external parameters affect both the amount of material removed and the physical properties of the plasma would aid ...
Nonlinear Characterizing Of A New Titanium Nitride On Aluminum Oxide Metalens, 2019 Air Force Institute of Technology
Nonlinear Characterizing Of A New Titanium Nitride On Aluminum Oxide Metalens, Michael A. Cumming
Theses and Dissertations
A sample metalens generated from Titanium Nitride deposited onto Aluminum Oxide was designed to focus at 10 microns with a beam centered at 800nm, and when analyzed with high intensity illumination was found to have a focal length of 9.650 ±.003µm at an intensity of 16.93[MW/cm2 ]. Analyzing this change by comparing it to a Fresnel Lens’ physics shows that for this lens, the effective nonlinear index of refraction is certainly greater than the nonlinear index of just Titanium Nitride itself, at −1.6239 × 10−15[m2/W] compared to the materials −1.3 × 10 ...
Obituary: Anthony Starace (1945-2019), 2019 University of Nebraska - Lincoln
Obituary: Anthony Starace (1945-2019)
Anthony F. Starace Publications
Anthony Starace, George Holmes University Professor of physics, died Sept. 5 from complications related to pancreatitis. He was 74.
Starace was born July 24, 1945, in the Queens borough of New York City. He graduated from Stuyvesant High School and earned his bachelor’s degree from Columbia University in 1966 before moving west to the University of Chicago, where he earned his doctorate under adviser Ugo Fano in 1971. It was in Chicago that he met Katherine Fritz of Beatrice, Nebraska, his wife of 51 years.
Following a postdoctoral appointment at Imperial College London, Starace moved to Lincoln as an ...
Numerical Simulation Of Unstable Laser Resonators With A High Gain Medium, 2019 Air Force Institute of Technology
Numerical Simulation Of Unstable Laser Resonators With A High Gain Medium, Robert L. Lloyd
Theses and Dissertations
This research focused on the numeric simulation of unstable laser resonators with high gain media. In order to accomplish the research, the modes and eigenvalues for various bare cavity resonator were computed followed by modes of a resonator in the presence of gain. Using a Fourier Split Step Method in a Fox and Li iteration scheme, different laser outputs for various laser cavities with gain were computed. Various parameters defining positive branch confocal unstable resonators were chosen corresponding to four studies. The four studies focused on modifying laser cavity Fresnel number, gain medium parameters, gain cell position, and gain cell ...
On The Pulsed Laser Ablation Of Metals And Semiconductors, 2019 Air Force Institute of Technology
On The Pulsed Laser Ablation Of Metals And Semiconductors, Todd A. Van Woerkom
Theses and Dissertations
This dissertation covers pulsed laser ablation of Al, Si, Ti, Ge, and InSb, with pulse durations from tens of picosecond to hundreds of microseconds, fluences from ones of J/cm2 to over 10,000 J/cm2, and in ambient air and vacuum. A set of non-dimensional scaling factors was created to interpret the data relative to the laser and material parameters, and it was found that pulse durations shorter than a critical timescale formed craters much larger than the thermal diffusion length, and longer pulse durations created holes much shallower than the thermal diffusion length. Low transverse order ...
Polarization Properties Of Airy And Ince-Gaussian Laser Beams, 2019 University of Arkansas, Fayetteville
Polarization Properties Of Airy And Ince-Gaussian Laser Beams, Sean Michael Nomoto
Theses and Dissertations
The description of polarization states of laser light as linear, circular polarization within the paraxial scalar wave approximation is adequate for most applications. However, this description falls short when considering laser light as an electromagnetic wave satisfying Maxwell's equations. An electric field with a constant unit vector for direction of the field and a space dependent complex scalar amplitude in the paraxial wave approximation does not satisfy Maxwell equations which, in general, requires all three Cartesian components of electric and magnetic fields associated for a nonzero laser beam to be nonzero.
Physical observation of passing a linearly polarized laser ...
Plasma Spectroscopy Of Titanium Monoxide For Characterization Of Laser Ablation, Todd A. Van Woerkom, Glen P. Perram, Christian G. Parigger, Brian D. Dolasinski, Charles D. Phelps, Patrick A. Berry
Ablation of titanium wafers in air is accomplished with 60 µs pulsed, 2.94 µm laser radiation. Titanium monoxide spectra are measured in the wavelength range of 500 nm to 750 nm, and molecular signatures include bands of the C3 Δ → X3 Δ α, B3 Π → X3 Δ γ', and A3 Φ → X3 Δ γ transitions. The spatially and temporally averaged spectra appear to be in qualitative agreement with previous temporally resolved studies that employed shorter wavelengths and shorter pulse durations than utilized in this work. The background signals in the current study are possibly due to particulate content in ...
Increasing The Functionality Of Additive Manufacturing Through Atmospheric Microplasma And Nanotechnology, 2019 Louisiana Tech University
Increasing The Functionality Of Additive Manufacturing Through Atmospheric Microplasma And Nanotechnology, Alexander Jon Ulrich
Additive Manufacturing (AM) has been changing the manufacturing landscape for the last 20 years. As the interest and demand for both polymer and metal-based 3D printing has grown, the materials and machines used have increased in capabilities. Despite the growth and advancement, there are still a large number of improvements that can be made to add functionality to 3D printers. Metal AM, a subcategory of 3D printing, has garnered much attention among industrial applications with large companies such as General Electric trying to implement the technology to increase innovative designs for motors. Some of the limitations on AM have to ...
Effects Of Pulse Width On He Plasma Jets In Contact With Water Evaluated By Oh(A-X) Emission And Ohaq Production, 2019 Old Dominion University
Effects Of Pulse Width On He Plasma Jets In Contact With Water Evaluated By Oh(A-X) Emission And Ohaq Production, Shutong Song, Esin B. Sözer, Chunqi Jiang
Nanosecond pulsed helium plasma jets impinging on water produce hydroxyl radicals both in gas- and liquid-phase. In this study, the effects of pulse width on a repetitively pulsed plasma jet in contact with water are evaluated via OH(A-X) emission and OHaq production in water for various pulse widths ranging from 200 to 5000 ns. The maximal energy efficiency of OH(A-X) emission is obtained for pulse widths of 600-800 ns whereas the maximal efficiency of OHaq production is at 200 ns. Temporally-resolved emission spectroscopy shows that more than 40% of OH(A-X) emission is produced during the ...
Performance Of Plastic Electron Optics Components Fabricated Using A 3d Printer, 2019 University of Nebraska–Lincoln
Performance Of Plastic Electron Optics Components Fabricated Using A 3d Printer, Phillip Wiebe, Peter Beierle, Hua-Chieh Shao, Bret Gergely, Anthony F. Starace, Herman Batelaan
Anthony F. Starace Publications
We show images produced by an electron beam deflector, a quadrupole lens and a einzel lens fabricated from conducting and non-conducting plastic using a 3D printer. Despite the difficulties associated with the use of plastics in vacuum, such as outgassing, poor conductivity, and print defects, the devices were used successfully in vacuum to steer, stretch and focus electron beams to millimeter diameters. Simulations indicate that much smaller focus spot sizes might be possible for such 3D-printed plastic electron lenses taking into account some possible surface defects. This work was motivated by our need to place electron optical components in difficult-to-access ...
Slow Light With Interleaved P-N Junction To Enhance Performance Of Integrated Mach-Zehnder Silicon Modulators, 2019 Dept. of Physics, University of Pavia, Pavia, Italy
Slow Light With Interleaved P-N Junction To Enhance Performance Of Integrated Mach-Zehnder Silicon Modulators, Marco Passoni, Dario Gerace, Liam O'Faolain, Lucio Claudio Andreani
Slow light is a very important concept in nanophotonics, especially in the context of photonic crystals. In this work, we apply our previous design of band-edge slow light in silicon waveguide gratings [M. Passoni et al, Opt. Express 26, 8470 (2018)] to Mach-Zehnder modulators based on the plasma dispersion effect. The key idea is to employ an interleaved p-n junction with the same periodicity as the grating, in order to achieve optimal matching between the electromagnetic field profile and the depletion regions of the p-n junction. The resulting modulation efficiency is strongly improved as compared to common modulators based on ...