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2016

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Articles 1381 - 1397 of 1397

Full-Text Articles in Physics

Resonant Collisions Of Potassium Atoms, Philip Michael Adamson Jan 2016

Resonant Collisions Of Potassium Atoms, Philip Michael Adamson

Honors Theses

This thesis discusses an approach to excite potassium atoms to very highly excited states (Rydberg states), and then tune their energy levels to induce resonant collisions between atoms. Potassium gas is super-cooled to 1 mK and confined to a small volume in a magneto-optical trap. A 405 nm laser diode, electronically locked to a potassium vapor cell via Doppler free spectroscopy, excites these atoms from the 4s1/2 state (ground state) to the 5p3/2 state. A 978 nm laser then excites the 5p3/2 to nd3/2 or nd5/2 transition, creating Rydberg atoms. Since there is no ground …

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20 Years Of Microplasma Research: A Status Report, Karl H. Schoenbach, Kurt Becker Jan 2016

20 Years Of Microplasma Research: A Status Report, Karl H. Schoenbach, Kurt Becker

Bioelectrics Publications

The field of microplasmas gained recognition as a well-defined area of research and application within the larger field of plasma science and technology about 20 years ago. Since then, the activity in microplasma research and applications has continuously increased. A survey of peer reviewed papers on microplasmas published annually shows a steady increase from fewer than 20 papers in 1995 to about 75 in 2005 and more than 150 in 2014. This count excludes papers that deal exclusively with technological applications where the microplasma is used solely as a tool. This topical review aims to provide a snap shot of …

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Towards An Understanding Of Pharmacologically Induced Intracellular Changes In Nicotinic Acetylcholine Receptors: A Fluorescence Microscopy Approach, Ashley M. Loe Jan 2016

Towards An Understanding Of Pharmacologically Induced Intracellular Changes In Nicotinic Acetylcholine Receptors: A Fluorescence Microscopy Approach, Ashley M. Loe

Theses and Dissertations--Chemistry

Upregulation of nicotinic acetylcholine receptors (nAChRs) is a well-documented response to chronic nicotine exposure. Nicotinic acetylcholine receptors are pentameric ligand-gated ion channels consisting of alpha (α2-10) and beta (β2-4) subunits. Nicotine, an agonist of nAChRs, alters trafficking and assembly of some subtypes of nAChRs, leading to an increase in expression of high sensitivity receptors on the plasma membrane. These physiological changes in nAChRs are believed to contribute to nicotine addiction, although the mechanism of these processes has not been resolved. Recently, many studies have converged on the idea that nicotine induces upregulation by an intracellular mechanism. In this dissertation, expression …

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Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan Jan 2016

Understanding Electrical Conduction In Lithium Ion Batteries Through Multi-Scale Modeling, Jie Pan

Theses and Dissertations--Chemical and Materials Engineering

Silicon (Si) has been considered as a promising negative electrode material for lithium ion batteries (LIBs) because of its high theoretical capacity, low discharge voltage, and low cost. However, the utilization of Si electrode has been hampered by problems such as slow ionic transport, large stress/strain generation, and unstable solid electrolyte interphase (SEI). These problems severely influence the performance and cycle life of Si electrodes. In general, ionic conduction determines the rate performance of the electrode, while electron leakage through the SEI causes electrolyte decomposition and, thus, causes capacity loss. The goal of this thesis research is to design Si …

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Interference Energy Spectrum Of The Infinite Square Well, Mordecai Waegell, Yakir Aharonov, Taylor Lee Patti Jan 2016

Interference Energy Spectrum Of The Infinite Square Well, Mordecai Waegell, Yakir Aharonov, Taylor Lee Patti

Mathematics, Physics, and Computer Science Faculty Articles and Research

Certain superposition states of the 1-D infinite square well have transient zeros at locations other than the nodes of the eigenstates that comprise them. It is shown that if an infinite potential barrier is suddenly raised at some or all of these zeros, the well can be split into multiple adjacent infinite square wells without affecting the wavefunction. This effects a change of the energy eigenbasis of the state to a basis that does not commute with the original, and a subsequent measurement of the energy now reveals a completely different spectrum, which we call the interference energy spectrum of …

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No Return To Classical Reality, David Jennings, Matthew S. Leifer Jan 2016

No Return To Classical Reality, David Jennings, Matthew S. Leifer

Mathematics, Physics, and Computer Science Faculty Articles and Research

At a fundamental level, the classical picture of the world is dead, and has been dead now for almost a century. Pinning down exactly which quantum phenomena are responsible for this has proved to be a tricky and controversial question, but a lot of progress has been made in the past few decades. We now have a range of precise statements showing that whatever the ultimate laws of Nature are, they cannot be classical. In this article, we review results on the fundamental phenomena of quantum theory that cannot be understood in classical terms. We proceed by rst granting quite …

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Determination Of Rejected Landing Roll Runway Point-Of-No-Return And Go-Around In Transport Category Airplanes, Nihad E. Daidzic, Ph.D., Sc.D. Jan 2016

Determination Of Rejected Landing Roll Runway Point-Of-No-Return And Go-Around In Transport Category Airplanes, Nihad E. Daidzic, Ph.D., Sc.D.

International Journal of Aviation, Aeronautics, and Aerospace

The decelerate-accelerate-takeoff maneuver in transport category airplanes has been discussed. Mathematical model based on total energy conservation has been used to calculate the rejected landing point-of-no-return on a runway which will still enable the airplane to safely execute go-around and achieve regulatory screen heights and takeoff safety speeds. After this point has been exceeded or below the point-of-no-return speed no go-around should ever be considered. Landing long and fast and/or decelerating on slippery runways may very well result in an overrun which could be prevented if the go-around is attempted before reaching this critical runway point. The point-of-no-return on the …

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Band Gap Engineering Of N-Alloyed Ga2o3 Thin Films, Dongyu Song, Li Li, Bingsheng Li, Yu Sui, Aidong Shen Jan 2016

Band Gap Engineering Of N-Alloyed Ga2o3 Thin Films, Dongyu Song, Li Li, Bingsheng Li, Yu Sui, Aidong Shen

Publications and Research

The authors report the tuning of band gap of GaON ternary alloy in a wide range of 2.75 eV. The samples were prepared by a two-step nitridation method. First, the samples were deposited on 2-inch fused silica substrates by megnetron sputtering with NH3 and Ar gas for 60 minutes. Then they were annealed in NH3 ambience at different temperatures. The optical band gap energies are calculated from transmittance measurements. With the increase of nitridation temperature, the band gap gradually decreases from 4.8 eV to 2.05 eV. X-ray diffraction results indicate that as-deposited amorphous samples can crystallize into monoclinic and hexagonal …

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Measurements Of Electrostatic Double Layer Potentials With Atomic Force Microscopy, Jason Giamberardino Jan 2016

Measurements Of Electrostatic Double Layer Potentials With Atomic Force Microscopy, Jason Giamberardino

Theses and Dissertations

The aim of this thesis is to provide a thorough description of the development of theory and experiment pertaining to the electrostatic double layer (EDL) in aqueous electrolytic systems. The EDL is an important physical element of many systems and its behavior has been of interest to scientists for many decades. Because many areas of science and engineering move to test, build, and understand systems at smaller and smaller scales, this work focuses on nanoscopic experimental investigations of the EDL. In that vein, atomic force microscopy (AFM) will be introduced and discussed as a tool for making high spatial resolution …

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Hadronic Lorentz Violation In Chiral Perturbation Theory, Rasha Kamand Jan 2016

Hadronic Lorentz Violation In Chiral Perturbation Theory, Rasha Kamand

Theses and Dissertations

The leading-order Lorentz-violating hadronic Lagrange densities are constructed using chiral perturbation theory. This is done for both pions and nucleons starting from a two-flavor quark-level Lagrangian that consists of dimension-four Lorentzviolation operators. The effective Lagrangians are first constructed in the absence of external fields. The formalism is then extended to include interactions with external fields. The presence of Lorentz violation modifies the transformation behavior of external fields under the chiral group SU(2)L × SU(2)R. This in turn leads to modified pion and nucleon covariant derivatives. By expanding parts of both mesonic and baryonic Lagragians in terms of physical pion and …

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Exclusive Π− Electroproduction Off The Neutron In Deuterium In The Resonance Region, Ye Tian Jan 2016

Exclusive Π− Electroproduction Off The Neutron In Deuterium In The Resonance Region, Ye Tian

Theses and Dissertations

This dissertation focuses on extracting the exclusive γ∗n(p) → pπ-(p) reaction cross section from deuterium data. The existing γ∗n → pπ- event generator is modified to include the spectator (proton) information based on the CD-Bonn potential [28] to simulate the real data process. With this method, the exclusive quasi-free process is isolated successfully as demonstrated by the comparison of the spectator momentum distribution of the simulation with the missing momentum distribution of the data, and the kinematical final-state-interaction contribution factor RFSI is extracted directly from the data according to the ratio between the exclusive quasi-free and full cross sections. The …

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Rare Event Searches With Cuore Style Teo2 Bolometers, Nicholas Ivan Chott Jan 2016

Rare Event Searches With Cuore Style Teo2 Bolometers, Nicholas Ivan Chott

Theses and Dissertations

In this dissertation we report on the first search for solar axions from atomic transitions in the solar core. A search for the 14.4 keV axion from the ground state transition in 57Fe in the sun was also performed, via the axioelectric effect in TeO2 bolometers, in the CUORE-0 experiment. Both axion searches are performed in the scope of the DSFZ invisible axion model. An upper bound on the axion-electron coupling constant of gae ≤ 3.1 x 10-11 (95% CL) is obtained with 62.7 kg days of TeO2 exposure from the CUORICINO experiment. The CUORE-0 data results in a …

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Multicharged Carbon Ion Generation From Laser Plasma, Oguzhan Balki, Hani E. Elsayed-Ali Jan 2016

Multicharged Carbon Ion Generation From Laser Plasma, Oguzhan Balki, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Carbon ions generated by ablation of a carbon target using an Nd:YAG laser pulse (wavelength λ = 1064 nm, pulse width τ = 7 ns, and laser fluence of 10-110 J cm-2) are characterized. Time-of-flight analyzer, a three-mesh retarding field analyzer, and an electrostatic ion energy analyzer are used to study the charge and energy of carbon ions generated by laser ablation. The dependencies of the ion signal on the laser fluence, laser focal point position relative to target surface, and the acceleration voltage are described. Up to C4+ ions are observed. When no acceleration voltage is applied between the …

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Rapid And Accurate C-V Measurements, Ji-Hong Kim, Pragya R. Shrestha, Jason P. Campbell, Jason T. Ryan, David Nminibapiel, Joseph J. Kopanski Jan 2016

Rapid And Accurate C-V Measurements, Ji-Hong Kim, Pragya R. Shrestha, Jason P. Campbell, Jason T. Ryan, David Nminibapiel, Joseph J. Kopanski

Electrical & Computer Engineering Faculty Publications

We report a new technique for the rapid measurement of full capacitance-voltage (C-V) characteristic curves. The displacement current from a 100-MHz applied sine wave, which swings from accumulation to strong inversion, is digitized directly using an oscilloscope from the MOS capacitor under test. A C-V curve can be constructed directly from this data but is severely distorted due to nonideal behavior of real measurement systems. The key advance of this paper is to extract the system response function using the same measurement setup and a known MOS capacitor. The system response correction to the measured C-V curve of the unknown …

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Easily Accessible Experiments Demonstrating Interference, Robert Polak, Nicolette Fudala, Jason T. Rothchild, Marcin Zelek Jan 2016

Easily Accessible Experiments Demonstrating Interference, Robert Polak, Nicolette Fudala, Jason T. Rothchild, Marcin Zelek

Physics: Faculty Publications and Other Works

A brief but detailed description of simple experiments to be used in Physics classrooms.

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An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants, Kishan Bellur Jan 2016

An Assessment Of The Validity Of The Kinetic Model For Liquid-Vapor Phase Change By Examining Cryogenic Propellants, Kishan Bellur

Dissertations, Master's Theses and Master's Reports

Evaporation is ubiquitous in nature and occurs even in a microgravity space envi- ronment. Long term space missions require storage of cryogenic propellents and an accurate prediction of phase change rates. Kinetic theory has been used to model and predict evaporation rates for over a century but the reported values of accommodation coefficients are highly inconsistent and no accurate data is available for cryogens. The proposed study involves a combined experimental and computational approach to ex- tract the accommodation coefficients. Neutron imaging is used as the visualization technique due to the difference in attenuation between the cryogen and the metallic …

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Slip-Jump Model For Carbon Combustion Synthesis Of Complex Oxide Nanoparticles, A. A. Markov, Mkhitar A. Hobosyan, Karen S. Martirosyan Jan 2016

Slip-Jump Model For Carbon Combustion Synthesis Of Complex Oxide Nanoparticles, A. A. Markov, Mkhitar A. Hobosyan, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

Carbon Combustion Synthesis of Oxides (CCSO) is a promising method to produce submicron- and nano- sized complex oxides. The CCSO was successfully utilized for producing several complex oxides, a complete theoretical model including the sample porosity, fl ow parameters and reaction energetics is needed to predict the combustion parameters for CCSO. In this work, we studied the ignition temperature and combustion wave axial temperature distribution, activation energy, combustion heat and thermal losses for a typical CCSO synthesis for cylindrical samples of Ni-Zn ferrites with high (>85%) porosity. We developed a two level combustion model of chemically active nano-dispersed mixture, …

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