Engineering Physics Commons^™

Investigation Of Phonon Polaritons In An Hbn Gan Heterostructure, Catherine G. O'Hearn

Graduate Theses, Dissertations, and Problem Reports (ETD)

There have been many great advances in the generation and manipulation of optics in the visible and near infrared (IR) range over the past decade. This is largely due to plasmonic enhancement, which has led to new technology in biosensing and molecule detection, solid-state lighting, and solar energy harvesting. The field of plasmonics uses quanta of plasma oscillations, plasmons, formed from the interaction between electromagnetic radiation and free electrons to enhance optical near field magnitudes. However, there is still a large region of the electromagnetic spectrum, covering the mid-infrared (MIR) and terahertz (THz) regions, ranging from 3 μm to 1 …

Synthesis Of Graphene Using Plasma Etching And Atmospheric Pressure Annealing: Process And Sensor Development, Andrew Robert Graves

Graduate Theses, Dissertations, and Problem Reports (ETD)

Having been theorized in 1947, it was not until 2004 that graphene was first isolated. In the years since its isolation, graphene has been the subject of intense, world-wide study due to its incredibly diverse array of useful properties. Even though many billions of dollars have been spent on its development, graphene has yet to break out of the laboratory and penetrate mainstream industrial applications markets. This is because graphene faces a ‘grand challenge.’ Simply put, there is currently no method of manufacturing high-quality graphene on the industrial scale. This grand challenge looms particularly large for electronic applications where the …

2d Confinement Of Thermal Gradients In Metallic Non-Local Spin Valves, Rachel K. Bennet

Electronic Theses and Dissertations

Non-local spin valves (NLSVs) are a valuable tool in the growing field of spintronics due to their unique ability to separate charge current from pure spin current. Their potential applications as read heads for hard-disk drives, as well as use as logic gates and other spin sensors, makes detailed understanding of their behavior under a wide range of operating conditions very important.

In this dissertation, I present results of extreme thermal engineering of the supporting substrate of NLSVs, which has a dramatic impact on the background signal of the device as well as contributions from thermal spin effects such as …

Improving Inverse Compton Sources By Avoiding Non-Linearities, B. Terzić, G. A. Krafft, V. Petrillo, I. Drebot, M. Ruijter

Physics Faculty Publications

We present a new, more nuanced understanding of non-linear effects in inverse Compton sources. Deleterious non-linear effects can arise even at low laser intensities, a regime previously viewed as linear. After laying out a survey of non-linear phenomena which degrade the effectiveness of inverse Compton sources, we discuss two powerful techniques designed to avoid these non-linearities. Starting with the known technique of non-linear longitudinal chirping of the laser pulse in the high laser field regime, we show that the simple stretching of the laser pulse, while keeping the energy constant, can significantly increase the spectral density of the scattered radiation …

High-Luminosity Large Hadron Collider (Hl-Lhc): Technical Design Report, O. Aberle, C. Adorisio, A. Adraktas, M. Ady, J. Albertone, L. Alberty, M. Alcaide Leon, A. Alekou, D. Alesini, B. Almeida Ferreira, P. Alvarez-Lopez, G. Ambrosio, P. Andreu Munoz, M. Anerella, D. Angal-Kalinin, F. Antoniou, G. Apollinari, A. Apollonio, R. Appleby, I. Béjar Alonso, Jean Delayen, I. Zurbano Fernandez, Et Al., I. Béjar Alonso (Ed.), O. Brüning (Ed.), P. Fessia (Ed.), M. Lamont (Ed.), L. Rossi (Ed.), L. Tavian (Ed.), M. Zerlauth (Ed.)

Physics Faculty Publications

The Large Hadron Collider (LHC) is one of the largest scientific instruments ever built. Since opening up a new energy frontier for exploration in 2010, it has gathered a global user community of about 9000 scientists working in fundamental particle physics and the physics of hadronic matter at extreme temperature and density. To sustain and extend its discovery potential, the LHC will need a major upgrade in the 2020s. This will increase its instantaneous luminosity (rate of collisions) by a factor of five beyond the original design value and the integrated luminosity (total number of collisions) by a factor ten. …

Observation Of In-Plane Magnetic Field Induced Phase Transitions In Fese, Jong Mok Ok, Chang Il Kwon, Yoshimitsu Kohama, Jung Sang You, Sun Kyu Park, Ji-Hye Kim, Y.J. Jo, E.S. Choi, Koichi Kindo, Woun Kang, Ki-Seok Kim, E. G. Moon, Alex Gurevich, Jun Sung Kim

Physics Faculty Publications

We investigate thermodynamic properties of FeSe under in-plane magnetic fields using torque magnetometry, specific heat, and magnetocaloric measurements. Below the upper critical field H_c2, we observed the field induced anomalies at H₁ ∼ 15 T and H₂ ∼ 22 T near H ∥ ab and below a characteristic temperature T* ∼ 2 K. The transition magnetic fields H₁ and H₂ exhibit negligible dependence on both temperature and field orientation. This contrasts to the strong temperature and angle dependence of H_c2, suggesting that these anomalies are attributed to the field induced phase transitions, …

Developing A High Resolution Zdc For The Eic, J. H. Lee, T. Sako, K. Tanida, M. Murray, Q. Wang, N. Nickel, Y. Yamazaki, Y. Itow, H. Menjo, T. Shibata, C. E. Hyde, V. Baturin, Y. Goto, I. Nakagawa, R. Seidl, K. Kawade, A. Deshpande, B. Schmookler, K. Nakano, T. Chujo, Y. Miyachi

Physics Faculty Publications

The Electron Ion Collider offers the opportunity to make un-paralleled multidimen- sional measurements of the spin structure of the proton and nuclei, as well as a study of the onset of partonic saturation at small Bjorken-x [1]. An important requirement of the physics program is the tagging of spectator neutrons and the identification of forward photons. We propose to design and build a Zero Degree Calorimeter, or ZDC, to measure photons and neutrons with excellent energy & position resolution.

Thermal Emittance And Lifetime Of Alkali-Antimonide Photocathodes Grown On Gaas And Molybdenum Substrates Evaluated In A -300 Kv Dc Photogun, Y. Wang, M. A. Mamun, P. Adderley, B. Bullard, J. Grames, J. Hansknecht, C. Hernandez-Garcia, G. A. Krafft, G. Palacios-Serrano, M. Poelker, M. L. Stutzman, R. Suleiman, M. Tiefenback, S. Wijethunga, J. Yoskowitz, S. Zhang

Physics Faculty Publications

Cs_xK_ySb photocathodes grown on GaAs and molybdenum substrates were evaluated using a –300 kV dc high voltage photogun and diagnostic beam line. Photocathodes grown on GaAs substrates, with varying antimony layer thickness (estimated range from < 20 nm to > 1 um), yielded similar thermal emittance per rms laser spot size values (~0.4 mm mrad / mm) but very different operating lifetime. Similar thermal emittance was obtained for a photocathode grown on a molybdenum substrate but with markedly improved lifetime. For this photocathode, no decay in quantum efficiency was measured at 4.5 mA average current and with peak current 0.55 A …

Flux Expulsion In Niobium Superconducting Radio-Frequency Cavities Of Different Purity And Essential Contributions To The Flux Sensitivity, P. Dhakal, Gianluigi Ciovati, Alex Gurevich

Physics Faculty Publications

Magnetic flux trapped during the cooldown of superconducting radio-frequency cavities through the transition temperature due to incomplete Meissner state is known to be a significant source of radio-frequency losses. The sensitivity of flux trapping depends on the distribution and the type of defects and impurities which pin vortices, as well as the cooldown dynamics when the cavity transitions from a normal to superconducting state. Here we present the results of measurements of the flux trapping sensitivity on 1.3 GHz elliptical cavities made from large-grain niobium with different purity for different cooldown dynamics and surface treatments. The results show that lower …

Intra- And Intermolecular Self-Assembly Of A 20-Nm-Wide Supramolecular Hexagonal Grid, Zhe Zhang, Yiming Li, Bo Song, Yuan Zhang, Xin Jiang, Ming Wang, Ryan Tumbleson, Changlin Liu, Pingshan Wang, Xin-Qi Hao, Tomas Rojas, Anh T. Ngo, Jonathan L. Sessler, George R. Newkome, Saw Wai Hla, Xiaopeng Li

Physics Faculty Publications

For the past three decades, the coordination-driven self-assembly of three-dimensional structures has undergone rapid progress; however, parallel efforts to create large discrete two-dimensional architectures—as opposed to polymers—have met with limited success. The synthesis of metallo-supramolecular systems with well-defined shapes and sizes in the range of 10–100 nm remains challenging. Here we report the construction of a series of giant supramolecular hexagonal grids, with diameters on the order of 20 nm and molecular weights greater than 65 kDa, through a combination of intra- and intermolecular metal-mediated self-assembly steps. The hexagonal intermediates and the resulting self-assembled grid architectures were imaged at submolecular …

Effect Of Non-Thermal Atmospheric Pressure Plasma On Wound Bacteria And Cell Proliferation, Mohd Nasir Norhayati

Student Works (2020-2029)

Non-thermal plasma produced in the plasma jet at atmospheric pressure consists of many reactive species and free radicals. The use of the atmospheric plasma jet has been expanded from surface treatment on polymers and biomaterials to the application as plasma medicine. It has been studied as a tools for wound sterilizations, enhance wound healing, topical treatment of skin diseases caused by bacteria infection and cancer therapy in recent research. The current study aims to investigate the effect of plasma on chronic wound bacteria as a supplementary to wound management particularly for compromised patients. The common practice in wound management is …