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Triple-Differential Cross Sections In Three-Dimensional Kinematics For Electron-Impact-Ionization Dynamics Of Tetrahydrofuran At 250-Ev Projectile Energy, Xiaorui Xue, Deepthy Maria Mootheril, Esam Ali, Maomao Gong, Shaokui Jia, Jiaqi Zhou, Enliang Wang, Jian Xing Li, Xiangjun Chen, Don H. Madison, Alexander Dorn, Xueguang Ren

Physics Faculty Research & Creative Works

We report a combined experimental and theoretical study of the ionization dynamics of tetrahydrofuran induced by 250 eV electron impact in which the highest occupied molecular orbital is ionized leading to the stable parent ion. Experimentally a reaction microscope was used, covering nearly the entire 4π solid angle for the ejected slow electron. We present the triple-differential cross sections for the projectile scattering angles of θ1 = -10∘ as a function of the emission angle of the ejected electrons with energies of E2=10, 15, and 20 eV, i.e., for asymmetric energy sharing between the scattered and ejected electrons. The measured …

Transient Vision Loss Associated With Prefilled Aflibercept Syringes: A Case Series And Analysis Of Injection Force, Daniel J. Lee, Brittni A. Scruggs, Erik J. Sánchez, Merina Thomas, Ambar Faridi

Physics Faculty Publications and Presentations

Purpose

To describe cases of significant vision loss after intravitreal aflibercept administration using prefilled syringes (PFS) and to study the relationships among syringe design, injection speed, and injection force.

Design

Retrospective case series and experimental study.

Participants

Twelve patients who received intravitreal aflibercept via PFS.

Methods

All retina specialists (n = 13) at Oregon Health & Science University and the Veterans Affairs Portland Medical Center were queried in December 2020 to report episodes of significant vision loss after aflibercept PFS use. Chart review was completed for all affected patients. Using a commercially available force measuring system, injection force was measured …

Liposome Formulation For Tumor-Targeted Drug Delivery Using Radiation Therapy, Daniel Fologea

Physics Faculty Publications and Presentations

Targeted delivery of drugs or other therapeutic agents through internal or external triggers has been used to control and accelerate the release from liposomal carriers in a number of studies, but relatively few utilize energy of therapeutic X-rays as a trigger. We have synthesized liposomes that are triggered by ionizing radiation (RTLs) to release their therapeutic payload. These liposomes are composed of natural egg phosphatidylethanolamine (PE), 1,2-distearoyl-sn-glycero-3-phosphocholine (DSPC), cholesterol, and 1,2-disteroyl-sn-glycero-3-phosphoethanolamine-N-[methoxy (polyethylene glycol)-2000] (DSPE-PEG-2000), and the mean size of the RTL was in the range of 114 to 133 nm, as measured by nanoparticle tracking analysis (NTA). The trigger mechanism …

Phys 141h: Elementary General Physics I (Honors), Stephen Ducharme

Department of Physics and Astronomy: Syllabi

Syllabus for PHYS 141H: Elementary General Physics (Honors) syllabus for Fall 2022.

Emergence Of Ferrimagnetism In Li-Intercalated Nips3, Rabindra Basnet, Dawn Ford, Kaylee Tenbarge, Joshua Lochala, Jin Hu

Physics Faculty Publications and Presentations

Intercalation has become a powerful approach to tune the intrinsic properties and introduce novel phenomena in layered materials. Intercalating van der Waals (vdW) magnetic materials is a promising route to engineer the low-dimensional magnetism. Recently, metal thiophosphates, MPX₃, has been widely studied because their magnetic orders are highly tunable and persist down to the two-dimensional limit. In this work, we used electrochemical technique to intercalate Li into NiPS₃ single crystals and found the emergence of ferrimagnetism at low temperature in Li-intercalated NiPS₃. Such tuning of magnetic properties highlights the effectiveness of intercalation, providing …

Search For Triple-Proton Decay Using Machine Learning With Cuore, Douglas Adams

Theses and Dissertations

A framework to search for a triple-proton decay of ¹³⁰Te in the CUORE detector against a background of muons is presented. We use machine learning to classify different kinds of energy depositing events. We use the classification information to improve our detection or non-detection limits of a triple-proton decay process. We derive and use a methodology of combining Poisson counting statistics with supervised classification machine learning tools. Additionally, a sensitivity calculation is provided which uses the classification counting likelihood. Using our analysis technique, we achieve an lower 2σ half-life bound of 7.43×10²⁴yrs for triple-proton decay of …

Spectroscopic Study Of The 4f76s2 8S◦7/2 - 4f7(8S◦)6s6p(1P◦) 8P9/2 Transition In Neutral Europium-151 And Europium-153: Absolute Frequency And Hyperfine Structure, M. T. Herd, C. Maruko, M. M. Herzog, A. Brand, G. Cannon, B. Duah, N. Hollin, T. Karani, A. Wallace, M. Whitmore, W. D. Williams

Physics: Faculty Publications

We report on spectroscopic measurements on the 4 f 76s2 8S◦7/2 → 4 f 7(8S◦)6s6 p(1P◦) 8P9/2 transition in neutral europium-151 and europium-153 at 459.4 nm. The center of gravity frequencies for the 151 and 153 isotopes, reported for the first time in this paper, to our knowledge, were found to be 652,389,757.16(34) MHz and 652,386,593.2(5) MHz, respectively. The hyperfine coefficients for the 6s6 p(1P◦) 8P9/2 state were found to be A(151) = -228.84(2) MHz, B(151) = 226.9(5) MHz and A(153) = -101.87(6) MHz, B(153) = 575.4(1.5) MHz, which all agree with previously published results except for A(153), which shows …

Spirality: A Novel Way To Measure Spiral Arm Pitch Angle, Deanna Shields, Benjamin Boe, Casey Pfountz, Benjamin L. Davis, Matthew Hartley, Ryan Miller, Zac Slade, M. Shameer Abdeen, Daniel Kennefick, Julia Kennefick

Physics Faculty Publications and Presentations

We present the MATLAB code Spirality, a novel method for measuring spiral arm pitch angles by fitting galaxy images to spiral templates of known pitch. Computation time is typically on the order of 2 min per galaxy, assuming 8 GB of working memory. We tested the code using 117 synthetic spiral images with known pitches, varying both the spiral properties and the input parameters. The code yielded correct results for all synthetic spirals with galaxy-like properties. We also compared the code’s results to two-dimensional Fast Fourier Transform (2DFFT) measurements for the sample of nearby galaxies defined by DMS PPak. Spirality’s …

Memristive Ising Circuits, Vincent James Dowling

Theses and Dissertations

Resistance random access memory (ReRAM) cells are emerging passive components showing great promise for applications in non-volatile storage, in-memory computing, and neuromorphic circuits, to name a few. Various experimental ReRAM cells have demonstrated excellent characteristics. This includes nanoscale size, short read and write times, and small energy requirements needed to manipulate the information. The main obstacles preventing the widespread adoption of ReRAM technology are significant device-to-device and cycle-to-cycle variability.

In essence, ReRAM cells are resistors with memory whose state (resistance) can be changed by an applied signal such as voltage. Many models were developed for describing their response. These range …

Magnetic Field Directed Self-Assembly Of Colloidal Nanoparticles Via Extreme Field Gradients Of Magnetic Recording Media, Abdul Rahman Mohtasebzadeh

Theses and Dissertations

Magnetic nanoparticles have been extensively studied over the last half century and continue to sustain interest due to their potential use in different fields. This research explores Magnetic Field Directed Self-Assembly of magnetic nanoparticles using a magnetic disk drive. The magnetic fields generated by the bits in a magnetic disk drive have rapidly changing field gradients that can self-assemble magnetic nanoparticles into various shapes. We demonstrate the ability to record and read field gradients on a commercial disk drive medium and to use monodisperse iron oxide nanoparticles to achieve self-assembly. We use image analysis techniques to quantify parameters related to …

Diffraction-Free Beam Propagation At The Exceptional Point Of Non-Hermitian Glauber Fock Lattices, Cem Yuce, Hamidreza Ramezani

Physics & Astronomy Faculty Publications

We construct localized beams in a non-Hermitian Glauber Fock (NGF) lattice of coupled waveguides and show that they can propagate for a long distance without almost no diffraction. We specifically obtain the diffraction-free beams in a finite NGF lattice at the exceptional point (EP) by using the exact eigenstates of the semi-infinite unidirectional NGF lattice. We provide a numerical approach to finding other lattices that are capable of supporting non-diffracting beams at EPs.

Oxygen Vacancies In Lib3O5 Crystals And Their Role In Nonlinear Absorption, Brian C. Holloway, Christopher A. Lenyk, Timothy D. Gustafson, Nancy C. Giles

Faculty Publications

LiB₃O₅ (LBO) crystals are used to generate the second, third, and fourth harmonics of near-infrared solid-state lasers. At high power levels, the material’s performance is adversely affected by nonlinear absorption. We show that as-grown crystals contain oxygen and lithium vacancies. Transient absorption bands are formed when these intrinsic defects serve as traps for “free” electrons and holes created by x rays or by three- and four-photon absorption processes. Trapped electrons introduce a band near 300 nm and trapped holes produce bands in the 500-600 nm region. Electron paramagnetic resonance (EPR) is used to identify and characterize the …

Dynamical Excitation Processes And Correlations Of Three-Body Two-Dimensional Mixtures, G. Bougas, Simeon I. Mistakidis, P. Giannakeas, P. Schmelcher

Physics Faculty Research & Creative Works

A Scheme Is Proposed To Dynamically Excite Distinct Eigenstate Superpositions In Three-Body Bose-Fermi Mixtures Confined In A Two-Dimensional Harmonic Trap. The System Is Initialized In A Noninteracting State With A Variable Spatial Extent, And The Scattering Lengths Are Subsequently Quenched Spanning The Regime From Weak To Strong Interactions. For Spatial Widths Smaller Than The Three-Body Harmonic Oscillator Length, A Superposition Of Trimers And Atom-Dimers Is Dynamically Attained, Otherwise Trap States Are Predominantly Populated, As Inferred From The Frequency Spectrum Of The Fidelity. Accordingly, The Tan Contacts Evince The Buildup Of Short-Range Two- And Three-Body Correlations In The Course Of The …

Control Of Dy 164 Bose-Einstein Condensate Phases And Dynamics With Dipolar Anisotropy, S. Halder, K. Mukherjee, Simeon I. Mistakidis, S. Das, P. G. Kevrekidis, P. K. Panigrahi, S. Majumder, H. R. Sadeghpour

Physics Faculty Research & Creative Works

We Investigate The Quench Dynamics Of Quasi-One- And Two-Dimensional Dipolar Bose-Einstein Condensates Of Dy164 Atoms Under The Influence Of A Fast Rotating Magnetic Field. The Magnetic Field Thus Controls Both The Magnitude And Sign Of The Dipolar Potential. We Account For Quantum Fluctuations, Critical To Formation Of Exotic Quantum Droplet And Supersolid Phases In The Extended Gross-Pitaevskii Formalism, Which Includes The So-Called Lee-Huang-Yang Correction. An Analytical Variational Ansatz Allows Us To Obtain The Phase Diagrams Of The Superfluid And Droplet Phases. The Crossover From The Superfluid To The Supersolid Phase And To Single And Droplet Arrays Is Probed With Particle …

Sum Rules For Energy Deposition Eigenchannels In Scattering Systems, Alexey Yamilov, Nicholas Bender, Hui Cao

Physics Faculty Research & Creative Works

In a random-scattering system, the deposition matrix maps the incident wavefront onto the internal field distribution across a target volume. The corresponding eigenchannels have been used to enhance the wave energy delivered to the target. Here, we find the sum rules for the eigenvalues and eigenchannels of the deposition matrix in any system geometry: including two- and three-dimensional scattering systems, as well as narrow waveguides and wide slabs. We derive a number of constraints on the eigenchannel intensity distributions inside the system as well as the corresponding eigenvalues. Our results are general and applicable to random systems of arbitrary scattering …

A Mode-Sum Prescription For The Renormalized Stress Energy Tensor On Black Hole Spacetimes, Peter Taylor, Cormac Breen, Adrian Ottewill

Articles

In this paper, we describe an extremely efficient method for computing the renormalized stress-energy tensor of a quantum scalar field in spherically symmetric black hole spacetimes. The method applies to a scalar field with arbitrary field parameters. We demonstrate the utility of the method by computing the renormalized stress-energy tensor for a scalar field in the Schwarzschild black hole spacetime, applying our results to discuss the null energy condition and the semiclassical backreaction.

Investigation Of Adhesion, Deformation Mechanics, And Electrical Properties Of Ag/Sio2/Pdms Tri-Layers For Stretchable Electronic Applications, Rhandy Joe Paladines

Theses and Dissertations

The motivation behind this research is to improve the interfacial layer bonding of metallic thin films to PDMS substrates with the aid of a buffer layer. The physical vapor deposition (PVD) technique of sputtering was used to deposit bilayer thin films of silver (Ag) and silicon dioxide (SiO2) on PDMS. Two chamber pressures were used in this work, 5 and 20 mTorr, to investigate the role of this parameter in determining the interfacial adhesion and the role in determining the resistance sensitivity. Studies of the surface energy and increased bonding strength for metallization are carried out. Surface characterization using atomic …

Microstructural Origin Of The High-Energy Storage Performance In Epitaxial Lead-Free Ba(Zr 0.2 Ti 0.8 )O 3 Thick Films, Jun Ouyang, Xianke Wang, Changtao Shao, Hongbo Cheng, Hanfei Zhu, Yuhang Ren

Publications and Research

In our previous work, epitaxial Ba(Zr 0.2 Ti 0.8 )O 3 thick films (~1–2 μ m) showed an excellent energy storage performance with a large recyclable energy density (~58 J/cc) and a high energy efficiency (~92%), which was attributed to a nanoscale entangled heterophase polydomain structure. Here, we propose a detailed analysis of the structure–property relationship in these film materials, using an annealing process to illustrate the effect of nanodomain entanglement on the energy storage performance. It is revealed that an annealing-induced stress relaxation led to the segregation of the nanodomains (via detailed XRD analyses), and a degraded energy storage …

Comparative Photovoltaics Of P3ht:N2200 And P3ht: Small-Gap Fullerene Ethyl-Nipecotate Bulk Heterojunction Structures, Md. Nasir Uddin, Rafiqul Islam, Muhibur Rahman, Nazia Chawdhury

Makara Journal of Science

This work deals with the study on the optical absorption and photoluminescence spectra of a p-type organic semiconducting polymer, regioregular poly 3-hexylthiophene-2,5-diyl (P3HT) and the absorption spectra of an n-type fullerene-based small-gap fullerene-ethyl nipecotate (Fullerene-EN) and a non-fullerene-based polynaphthalene bithiophene (N2200) semiconducting materials. The band gap of P3HT, N2200, and small-gap fullerene-ethyl nipecotate are 2.42, 1.65, and 1.51 eV, respectively, calculated from experimental results through the Tauc equation. Active layers with blends of P3HT and small-gap fullerene-ethyl nipecotate and P3HT and N2200 have been used to fabricate bulk heterojunction (BHJ) structures. The P3HT:N2200 BHJ structure follows the current density versus …

Pulsed Lased Deposition Of Single-Crystalline (001) Oriented Pb(Zr0.5t0.5)O3 Thin Film On Prsco3 Substrate, Mahamudu H. Mtebwa, Nava Setter

Tanzania Journal of Science

High quality thin films are important for domain engineering applications such as on-volatile memory applications. Single crystalline (001) oriented Pb (Zr0.5T0.5)O3 thin films have been grown by pulsed laser deposition on PrScO3 with strontium ruthenate (SRO) electrodes. Thin films were prepared from PZT ceramic targets with 15% excess PbO to compensate for lead loss at high deposition temperature. Layer by layer/step flow growth mode observed on AFM images has been realised by using a single terminated PrScO3 substrate as well as optimized deposition parameters. XRD measurements have confirmed the highly (001) oriented tetragonal symmetry. Furthermore, analysis conducted using piezoresponse force …

Effects Of Multilayer Structure On The Microstructure And Optical Properties Of The Dc Sputtered Chromium Thin Films For Selective Solar Absorber Applications, Justine J. Tibaijuka, Margaret E. Samiji, Mmantsae Diale, Nuru R. Mlyuka

Tanzania Journal of Science

Chromium thin films exhibit several properties that make them potential for solar thermal applications. In this work the effect of film thickness and sputtering power based multilayer structure on the optical properties of DC sputtered chromium thin films is reported. The structural, topological, and optical properties of these films were determined by X-ray diffractometer, Atomic Force Microscopy, and Ultraviolet-Visible-Near Infrared spectrophotometer, respectively. XRD spectra revealed a single peak with preferential orientation of (200) and (210) for single layer and multilayer chromium films, respectively. The grain size and roughness were relatively higher for the multilayer compared to single layer Chromium films. …

Dynamic Remodeling Of Fiber Networks With Stiff Inclusions Under Compressive Loading, Robert J. Carroll, Minh H. Thanh, Alison E. Patteson

Physics - All Scholarship

The ability of tissues to sustain and withstand mechanical stress is critical to tissue development and healthy tissue maintenance. The mechanical properties of tissues are typically considered to be dominated by the fibrous extracellular matrix (ECM) component of tissues. Fiber network mechanics can capture certain mechanical features of tissues, such as shear strain stiffening, but is insufficient in describing the compressive response of certain tissues and blood clots that are rich in extracellular matrix. To understand the mechanical response of tissues, we employ a contemporary mechanical model, a fibrous network of fibrin embedded with inert bead inclusions that preserve the …

Measurement Of The Mass Dependence Of The Transverse Momentum Of Lepton Pairs In Drell–Yan Production In Proton–Proton Collisions At √S = 13tev, A. Tumasyan

Department of Physics and Astronomy: Faculty Publications

The double differential cross sections of the Drell–Yan lepton pair (ℓ ⁺ ℓ ⁻, dielectron or dimuon) production are measured as functions of the invariant mass m_ℓℓ, transverse momentum p_T(ℓℓ), and ϕ^∗_η. The ϕ^∗_η observable, derived from angular measurements of the leptons and highly correlated with p_T(ℓℓ), is used to probe the low-p_T(ℓℓ) region in a complementary way. Dilepton masses up to 1 TeV are investigated. Additionally, a measurement is performed requiring at least one jet in the final state. To benefit from partial cancellation …

Biogeochemical Responses To Mixing Of Glacial Meltwater And Hot Spring Discharge In The Mount St. Helens Crater, Ashley Dubnick, Q. Faber, J. R. Hawkings, N. Bramall, B. C. Christner, Peter T. Doran, Jay Nadeau, C. Snyder, Multiple Additional Authors

Physics Faculty Publications and Presentations

Environments where geothermal waters and glacier meltwater mix are common on Earth yet little is known about the biogeochemical processes that occur when hot, reduced geothermal water mixes with cold, oxidized glacial meltwater in natural systems. Mount St. Helens provides an ideal location to study the interaction between geothermal and glacier waters since the water sources, and their mixing environment in Step Creek, are exposed in the volcanic crater. We find that the two water sources contain distinct major ion, trace element, dissolved organic matter (DOM), and biological signatures. The hot spring contains high concentrations of biogeochemically reactive components (e.g., …

Characterization Of Superconducting Hardware For Implementing Quantum Stabilizers, Kenneth Richard Dodge

Dissertations - ALL

Superconducting qubits are one of the leading approaches being investigated for building a scalable quantum computer. In the presence of external noise and perturbations plus local microscopic fluctuations and dissipation in the qubit environment, arbitrary quantum states will decohere, leading to bit-flip and phase-flip errors of the qubit. In order to build a fault-tolerant quantum computer that can preserve and process quantum information in the presence of noise and dissipation, one must implement some form of quantum error correction. Stabilizer operations are at the heart of quantum error correction and are typically implemented in software-controlled entangling gates and measurements of …

Spontaneous Polarization In An Ultrathin Improper-Ferroelectric/Dielectric Bilayer In A Capacitor Structure At Cryogenic Temperatures, Yu Yun, Pratyush Buragohain, Arashdeep Singh Thind, Yuewei Yin, Xin Li, Xuanyuan Jiang, Rohan Mishra, Alexei Gruverman, X. S. Xu

Department of Physics and Astronomy: Faculty Publications

To determine the effect of depolarization and the critical thickness in improper-ferroelectric hexagonal-ferrite thin films, we investigate the polarization switching of a ferroelectric/dielectric bilayer in capacitor structures at 20 K. Experimentally, we show that the spontaneous polarization persists throughout the studied thickness range (3 to 80 unit cell), even with a thick (10-nm) dielectric layer, suggesting no practical thickness limit for applications. By fitting the effect of depolarization using the phenomenological theory, we show that the spontaneous polarization remains finite when the thickness of the ferroelectric layer approaches zero, providing a hint for the absence of critical thickness. We also …

Miniaturized Iii-V/ Si Hybrid Laser With An Integrated Modulator, Praveen Kumar Singaravelu

Theses

Light interaction with microscopic and nanoscopic structures enable manipulation of its characteristics which can be used to detect objects in 3D sensing, propel satellites to space using photonic propulsion and transmit data through optical communication. For optical communication, the basic components are lasers, modulators and photodetectors. The development of CMOS microfabrication foundries helps to manufacture silicon-based photonic devices with high yield that is directly co-integrated with electronics in a single chip. However, the lack of emission of photons efficiently in silicon propelled the necessity of hybrid photonic devices that inherits the combined advantage of different materials i.e. functionality and volume. …

On A Novel Approach To The Thermogravimetric Analysis Of Polymers: Polystyrene, Mircea Chipara, Karen Lozano, Dorina M. Chipara, Carlos Delgado, Victoria Padilla

Physics & Astronomy Faculty Publications

A novel equation that describes the temperature dependence of the residual mass fraction (as determined by thermogravimetric analysis) is derived, assuming that the dependence of the residual mass fraction on temperature has a sigmoidal shape. The equation allows the estimation of the sigmoidal activation energy solely from the experimental data at a single heating rate. The consistency with the isoconversional approach and the relationship between the Ozawa and sigmoidal activation energies are reported. The equation was successfully tested by the thermal degradation of atactic polystyrene at various heating rates. Both the thermograms and their derivatives are analyzed in detail.

Classification Of Pixel Tracks To Improve Track Reconstruction From Proton-Proton Collisions, Kebur Fantahun, Jobin Joseph, Halle Purdom, Nibhrat Lohia

SMU Data Science Review

In this paper, machine learning techniques are used to reconstruct particle collision pathways. CERN (Conseil européen pour la recherche nucléaire) uses a massive underground particle collider, called the Large Hadron Collider or LHC, to produce particle collisions at extremely high speeds. There are several layers of detectors in the collider that track the pathways of particles as they collide. The data produced from collisions contains an extraneous amount of background noise, i.e., decays from known particle collisions produce fake signal. Particularly, in the first layer of the detector, the pixel tracker, there is an overwhelming amount of background noise that …

Search For Gravitational Waves From Scorpius X-1 With A Hidden Markov Model In O3 Ligo Data, R. Abbott, H. Abe, F. Acernese, K. Ackley, N. Adhikari, Michael G. Benjamin, Teviet Creighton, Mario C. Diaz, Francisco Llamas, Soma Mukherjee, Gaukhar Nurbek, Volker Quetschke, Wenhui Wang

Physics & Astronomy Faculty Publications

Results are presented for a semicoherent search for continuous gravitational waves from the low-mass x-ray binary Scorpius X-1, using a hidden Markov model (HMM) to allow for spin wandering. This search improves on previous HMM-based searches of Laser Interferometer Gravitational-Wave Observatory data by including the orbital period in the search template grid, and by analyzing data from the latest (third) observing run. In the frequency range searched, from 60 to 500 Hz, we find no evidence of gravitational radiation. This is the most sensitive search for Scorpius X-1 using a HMM to date. For the most sensitive subband, starting at …