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Articles 28321 - 28350 of 36710

Full-Text Articles in Physical Sciences and Mathematics

The First 80-Hour Continuous Lidar Campaign For Simultaneous Observation Ofmesopause Region Temperature And Wind, C. Y. She, J. Sherman, Tao Yuan, B. P. Williams, K. Arnold, T. D. Kawahara, T. Li, L. F. Xu, J. D. Vance, P. Acott, D. A. Krueger Mar 2003

The First 80-Hour Continuous Lidar Campaign For Simultaneous Observation Ofmesopause Region Temperature And Wind, C. Y. She, J. Sherman, Tao Yuan, B. P. Williams, K. Arnold, T. D. Kawahara, T. Li, L. F. Xu, J. D. Vance, P. Acott, D. A. Krueger

All Physics Faculty Publications

The Colorado State Sodium lidar has been upgraded to a two-beam system capable of simultaneous measurement of mesopause region temperature and winds, day and night, weather permitting. This paper reports the initial result of the first campaign, conducted in April 2002, with a total of 145 hours of observation including an 80-hour continuous data acquisition of temperature and zonal wind. The contour plots of the continuous data set show considerable coherence and activities of upward propagating waves, with a maximum day-night difference of 15.5 m/s in zonal wind at 88 km and of 10 K in temperature at 92 km. …

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Small Angle Neutron Scattering From D2o–H2o Nanodroplets And Binary Nucleation Rates In A Supersonic Nozzle, Christopher H. Heath, Kiril A. Streletzky, Barbara E. Wyslouzil, Judith Woelk, Reinhard Strey Mar 2003

Small Angle Neutron Scattering From D2o–H2o Nanodroplets And Binary Nucleation Rates In A Supersonic Nozzle, Christopher H. Heath, Kiril A. Streletzky, Barbara E. Wyslouzil, Judith Woelk, Reinhard Strey

Physics Faculty Publications

Small angle neutron scattering (SANS) experiments were used to characterize binary nanodroplets composed of D2O and H2O. The droplets were formed by expanding dilute mixtures of condensible vapor in a N2 carrier gas through a supersonic nozzle, while maintaining the onset of condensation at a fixed position in the nozzle. It is remarkable, given the small coherent scattering length density of light water, that even the pure H2O aerosol gave a scattering signal above background. The scattering spectra were analyzed assuming a log-normal distribution of droplets. On average, the geometric radius of the nanodroplets rg was rg=13 (±1) nm, the …

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The Adsorption Of Orthocarborane On Cobalt, L. Bernard, A. N. Caruso, Bo Xu, Bernard Doudin, Peter A. Dowben Mar 2003

The Adsorption Of Orthocarborane On Cobalt, L. Bernard, A. N. Caruso, Bo Xu, Bernard Doudin, Peter A. Dowben

Peter Dowben Publications

The adsorption of closo-1,2 dicarbadodecaborane (orthocarborane) on evaporated cobalt thin films has been investigated by combined photoemission and inverse photoemission studies. The adsorption of these icosahedral molecules does not strongly perturb the electronic structure of the underlying cobalt. As was previously observed with adsorption on Cu(100), electron induced decomposition of adsorbed orthocarborane decreases the HOMO–LUMO gap. The X-ray photoemission spectra before and after orthocarborane adsorption confirm that the interface with cobalt is abrupt. These results suggest that chemical vapor deposition, via the decomposition of orthocarborane, may be an effective method for fabricating dielectric barrier layers, without utilizing oxides. This …

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Grain Boundary Scars And Spherical Crystallography, Mark Bowick, A. R. Bausch Mar 2003

Grain Boundary Scars And Spherical Crystallography, Mark Bowick, A. R. Bausch

Physics - All Scholarship

We describe experimental investigations of the structure of two-dimensional spherical crystals. The crystals, formed by beads self-assembled on water droplets in oil, serve as model systems for exploring very general theories about the minimum energy configurations of particles with arbitrary repulsive interactions on curved surfaces. Above a critical system size we find that crystals develop distinctive high-angle grain boundaries, or scars, not found in planar crystals. The number of excess defects in a scar is shown to grow linearly with the dimensionless system size. The observed slope is expected to be universal, independent of the microscopic potential.

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Dynamics Of Conformal Maps For A Class Of Non-Laplacian Growth Phenomena, Martin Z. Bazant, Jaehyuk Choi, Benny Davidovitch Mar 2003

Dynamics Of Conformal Maps For A Class Of Non-Laplacian Growth Phenomena, Martin Z. Bazant, Jaehyuk Choi, Benny Davidovitch

Benny Davidovitch

Time-dependent conformal maps are used to model a class of growth phenomena limited by coupled non-Laplacian transport processes, such as nonlinear diffusion, advection, and electro- migration. Both continuous and stochastic dynamics are described by generalizing conformal- mapping techniques for viscous fingering and diffusion-limited aggregation, respectively. A gen- eral notion of time in stochastic growth is also introduced. The theory is applied to simulations of advection-diffusion-limited aggregation in a background potential flow. A universal crossover in mor- phology is observed from diffusion-limited to advection-limited fractal patterns with an associated crossover in the growth rate, controlled by a time-dependent effective Peclet number. …

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Consideration Of Possible Mass And Velocity Corrections To Magnetic Cluster Experiments, Z.Y. Liu, Peter A. Dowben, A.P. Popov, David P. Pappas Mar 2003

Consideration Of Possible Mass And Velocity Corrections To Magnetic Cluster Experiments, Z.Y. Liu, Peter A. Dowben, A.P. Popov, David P. Pappas

Peter Dowben Publications

Gadolinium occurs, in natural abundance, as several isotopes. The possible combinations of different gadolinium isotopes dictates that even for a fixed number of atoms in the cluster, clusters of gadolinium atoms will exhibit a range of masses. This and the expected consequence of the translation energy distributions are explored as possible corrections to Stern-Gerlach cluster beam-deflection experiments. Upon closer inspection of the experimental data, we find that the translation energy plus the vibrational temperature distribution may be inhomogeneous. This could be the origin of a long tail to high deflections in the experimental deflection profiles, at low cluster temperatures, in …

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Vacuum Choices And The Predictions Of Inflation, Christian Armendariz-Picon, Eugene A. Lim Mar 2003

Vacuum Choices And The Predictions Of Inflation, Christian Armendariz-Picon, Eugene A. Lim

Physics - All Scholarship

In the presence of a short-distance cutoff, the choice of a vacuum state in an inflating, non-de Sitter universe is unavoidably ambiguous. The ambiguity is related to the time at which initial conditions for the mode functions are specified and to the way the expansion of the universe affects those initial conditions. In this paper we study the imprint of these uncertainties on the predictions of inflation. We parametrize the most general set of possible vacuum initial conditions by two phenomenological variables. We find that the generated power spectrum receives oscillatory corrections whose amplitude is proportional to the Hubble parameter …

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Multiple Jet Production At Low Transverse Energies In Pp̅ Collisions At √S = 1.8 Tev, V. M. Abazov, Gregory R. Snow, D0 Collaboration Mar 2003

Multiple Jet Production At Low Transverse Energies In Pp̅ Collisions At √S = 1.8 Tev, V. M. Abazov, Gregory R. Snow, D0 Collaboration

Gregory Snow Publications

We present data on multiple production of jets with transverse energies near 20 GeV in pp̅ collisions at √s =1.8 TeV. QCD calculations in the parton-shower approximation of PYTHIA and HERWIG and the next-to-leading order approximation of JETRAD are compared to the data for one, two, three, and four jet inclusive production. Transverse energy spectra and multiple jet angular and summed transverse-energy distributions are adequately described by the shower approximation while next-to-leading order calculations describe the data poorly.

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Three-Dimensional Structure Of Magnetic Reconnection In A Laboratory Plasma, C. D. Cothran, Matthew Joseph Landreman , '03, Michael R. Brown, W. H. Matthaeus Mar 2003

Three-Dimensional Structure Of Magnetic Reconnection In A Laboratory Plasma, C. D. Cothran, Matthew Joseph Landreman , '03, Michael R. Brown, W. H. Matthaeus

Physics & Astronomy Faculty Works

The local three-dimensional structure of magnetic reconnection has been measured for the first time in a magnetohydrodynamic (MHD) laboratory plasma at the Swarthmore Spheromak Experiment. An array of 600 magnetic probes which resolve ion inertial length and MHD time scale dynamics on a single shot basis measured the magnetic structure of partial spheromak merging events. Counter-helicity spheromaks merge rapidly, and reconnection activity clearly self-generates a local component of B which breaks the standard 2D symmetry at the ion inertial scale. Consistent with prior results, no reconnection is observed for co-helicity merging.

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On The Initial Conditions For Brane Inflation, Scott Watson, Robert H. Brandenberger, G. Geshnizjani Mar 2003

On The Initial Conditions For Brane Inflation, Scott Watson, Robert H. Brandenberger, G. Geshnizjani

Physics - All Scholarship

String theory gives rise to various mechanisms to generate primordial inflation, of which ``brane inflation'' is one of the most widely considered. In this scenario, inflation takes place while two branes are approaching each other, and the modulus field representing the separation between the branes plays the role of the inflaton field. We study the phase space of initial conditions which can lead to a sufficiently long period of cosmological inflation, and find that taking into account the possibility of nonvanishing initial momentum can significantly change the degree of fine tuning of the required initial conditions.

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Magnetic Coupling In Co/Cr2O3/Cro2 "Trilayer" Films, Ruihau Cheng, A. N. Caruso, Lu Yuan, Sy_Hwang Liou, Peter A. Dowben Mar 2003

Magnetic Coupling In Co/Cr2O3/Cro2 "Trilayer" Films, Ruihau Cheng, A. N. Caruso, Lu Yuan, Sy_Hwang Liou, Peter A. Dowben

Peter Dowben Publications

The ferromagnetic coupling between Co and CrO2 , through an insulator (Cr2O3) was characterized by in situ magneto-optic Kerr effect. By evaporating 20–60 Å Co thin films on top of epitaxial CrO2 films, a Co/Cr2O3 /CrO2 trilayer system can be readily fabricated; this is possible because the native surface layer of CrO2 is Cr2O3 . In situ x-ray photoemission studies show that the Co is oxidized at the interface between Co and Cr2O3 , so that the system more resembles Co/CoO/Cr2O …

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Spacecraft Charging At Geosynchronous Altitudes: Current Balance And Critical Temperature In A Non-Maxwellian Plasma, Jose T. Harris Mar 2003

Spacecraft Charging At Geosynchronous Altitudes: Current Balance And Critical Temperature In A Non-Maxwellian Plasma, Jose T. Harris

Theses and Dissertations

Spacecraft charging threatens to disable spacecraft components and adversely impact any satellite function. Electrostatic charge, and especially discharge, can hinder the proper operation of, or destroy, spacecraft components, thereby rendering the spacecraft ineffective or inoperative. The level of charging is dependent on the particle energy (speed) distribution. Current spacecraft design and material provide limited protection against the dangers of electrostatic discharge, and active measures such as beam emission are also employed.

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Disorder-Induced Rounding Of Certain Quantum Phase Transitions, Thomas Vojta Mar 2003

Disorder-Induced Rounding Of Certain Quantum Phase Transitions, Thomas Vojta

Physics Faculty Research & Creative Works

We study the influence of quenched disorder on quantum phase transitions in systems with overdamped dynamics. For Ising order-parameter symmetry disorder destroys the sharp phase transition by rounding because a static order parameter can develop on rare spatial regions. This leads to an exponential dependence of the order parameter on the coupling constant. At finite temperatures the static order on the rare regions is destroyed. This restores the phase transition and leads to a double exponential relation between critical temperature and coupling strength. We discuss the behavior based on Lifshitz-tail arguments and illustrate the results by simulations of a model …

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Plasma-Etching-Enhanced Deep Centers In N-Gan Grown By Metalorganic Chemical-Vapor Deposition, Z-Q. Fang, David C. Look, X. L. Wang, J. Han, F. A. Khan, I. Adesida Mar 2003

Plasma-Etching-Enhanced Deep Centers In N-Gan Grown By Metalorganic Chemical-Vapor Deposition, Z-Q. Fang, David C. Look, X. L. Wang, J. Han, F. A. Khan, I. Adesida

Physics Faculty Publications

By using deep-level transient spectroscopy (DLTS), deep centers have been characterized in unintentionally doped n-GaN samples grown by metalorganic chemical-vapor deposition and subjected to inductively coupled plasma reactive ion etching. At least six DLTS traps exist in the control sample: A1 (∼0.90 eV), Ax (∼0.72 eV), B (0.61 eV), C1 (0.44 eV), D (0.25 eV), and E1 (0.17 eV), with B dominant. Then, as the etching bias-voltage increases from −50 to −150 V, trap D increases strongly and becomes dominant, while traps A1, C (0.34 eV), and E1 increase at a slower …

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Role Of The Tunneling Ray In Near-Critical-Angle Scattering By A Dielectric Sphere, James A. Lock Mar 2003

Role Of The Tunneling Ray In Near-Critical-Angle Scattering By A Dielectric Sphere, James A. Lock

Physics Faculty Publications

The scattering far zone for light transmitted through a sphere following p - 1 internal reflections by a family of near-grazing incident rays is subdivided into a lit region and a shadow region. The sharpness of the ray theory transition between the lit and the shadow regions is smoothed in wave theory by radiation shed by electromagnetic surface waves. It is shown that when higher-order terms in the physical optics approximation to the phase of the partial-wave scattering amplitudes are included, the transition between the lit and the shadow regions becomes a two-ray-to-zero-ray transition, called a superweak caustic in analogy …

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The Physical Interactions Between Hipco Swnts And Semi-Conjugated Polymers, Sinead Keogh, Theresa Hedderman, A. Maguire, M. G. Ruther, Elizabeth Gregan, Gordon Chambers, Hugh Byrne Mar 2003

The Physical Interactions Between Hipco Swnts And Semi-Conjugated Polymers, Sinead Keogh, Theresa Hedderman, A. Maguire, M. G. Ruther, Elizabeth Gregan, Gordon Chambers, Hugh Byrne

Conference papers

Hybrid systems of the conjugated organic polymer poly (p-phenylene vinylene-co-2,5- dioctyloxy -m-phenylene vinylene) (PmPV) and HiPco SWNT are explored using spectroscopic and thermal techniques to determine specific interactions. Vibrational spectroscopy indicates a weak interaction and this is further elucidated using Differential-Scanning Calorimetry and Temperature Dependent Raman pectroscopy. Two distinct transitions in region of -60C and + 60C are investigated.

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Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr. Mar 2003

Quantum Mechanical Calculations Of Monoxides Of Silicon Carbide Molecules, John W. Roberts Jr.

Theses and Dissertations

Modern semiconductor devices are principally made using the element silicon. In recent years, silicon carbide (SiC), with its wide band-gap, high thermal conductivity, and radiation resistance, has shown prospects as a semiconductor material for use in high temperature and radiation environments such as jet engines and satellites. A limiting factor in the performance of many SiC semiconductor components is the presence of lattice defects formed at oxide dielectric junctions during processing. Recent theoretical work has used small quantum mechanical systems embedded in larger molecular mechanics structures to attempt to better understand SiC surfaces and bulk materials and their oxidation. This …

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Afci Quarterly Input – Unlv January Through March, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division Mar 2003

Afci Quarterly Input – Unlv January Through March, 2003, Harry Reid Center For Environmental Studies. Nuclear Science And Technology Division

Transmutation Research Program Reports (TRP)

Quarterly report highlighting research projects and objectives of the Transmutation Research Program at the Nuclear Science & Technology Division, Harry Reid Research Center.

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High-Resolution Near-Field Raman Microscopy Of Single-Walled Carbon Nanotubes, Achim Hartschuh, X. Sunney Xie, Lukas Novotny, Erik J. Sánchez Mar 2003

High-Resolution Near-Field Raman Microscopy Of Single-Walled Carbon Nanotubes, Achim Hartschuh, X. Sunney Xie, Lukas Novotny, Erik J. Sánchez

Physics Faculty Publications and Presentations

We present near-field Raman spectroscopy and imaging of single isolated single-walled carbon nanotubes with a spatial resolution of approximately 25 nm. The near-field origin of the image contrast is confirmed by the measured dependence of the Raman scattering signal on tip-sample distance and the unique polarization properties. The method is used to study local variations in the Raman spectrum along a single single-walled carbon nanotube.

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Single-Mode Raman Fiber Laser In A Multimode Fiber, Matthew B. Crookston Mar 2003

Single-Mode Raman Fiber Laser In A Multimode Fiber, Matthew B. Crookston

Theses and Dissertations

The feasibility of a transverse single-mode Raman fiber laser using a multimode fiber has been investigated. The Raman fiber laser operates in low-order transverse modes despite the fact the fiber supports multimode beam propagation. The performance characteristics of the Raman fiber laser are compared with those of the single-pass SRS beam.

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Optical Characterization Of Antimony-Based, Types-I And Ii, Multiple Quantum-Well Semiconductor Structures For Mid-Infrared Laser Applications, Edward G. Ferguson Mar 2003

Optical Characterization Of Antimony-Based, Types-I And Ii, Multiple Quantum-Well Semiconductor Structures For Mid-Infrared Laser Applications, Edward G. Ferguson

Theses and Dissertations

This experiment characterizes antimony-based, multiple quantum-well, types-I and -II, semiconductor samples designed for laser applications. The samples emit light in the 3-5-micron range to exploit an atmospheric transmission window, making them ideal for infrared (IR)-seeking missile countermeasures. Photoluminescence (PL) spectra were collected and yielded bandgap (E(sub g)) dependence-on-temperature relationships. The type-I sample was found to follow the Varshni equation, while the type-II samples showed a rise with temperature in a portion of the curve that should be linear according to the Varshni equation. The type-II samples followed the Varshni equation well at higher temperature. The PL study indicated that the …

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Phasing A Dual Optical Path System Using An Optical Fiber As A Phase Conjugate Mirror, Shawn M. Willis Mar 2003

Phasing A Dual Optical Path System Using An Optical Fiber As A Phase Conjugate Mirror, Shawn M. Willis

Theses and Dissertations

Phase conjugation properties of stimulated Brillouin scattering (SBS) in a short multimode fiber have been investigated with an eye towards its application for a multi-channel double pass master oscillator power amplifier (MOPA) system. In particular, properties of the SBS beam to compensate for the axial and transverse phase distortion between individual channels in a multi-channel amplifier system were studied. Two optical paths were created by covering half of the laser beam with a microscope slide, and also by spatially splitting the wavefronts with a 4 prism set-up. The Stokes beams that traversed the same optical paths as the pump beams …

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Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela Mar 2003

Effect Of Multi-Mode Vibration On Signature Estimation Using A Laser Vibration Sensor, Ngoya Pepela

Theses and Dissertations

A laser vibration sensor (LVS) can be used to determine the vibrational spectrum of targets such as vehicles using heterodyne laser Doppler velocimetry. The vibrational spectra of exterior skin of vehicles are known to have characteristic resonances due to the physical structure driven by motor gears and other moving parts. Each particular class of vehicle has a unique vibrational spectrum. This research shows how a body vibrating in higher order modes has the opportunity to eliminate spectral content of the target's vibrational spectrum while using an LVS to perform spectrum estimation. This is due to roughly equal amounts of laser …

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Detection Of Special Nuclear Material With High Purity Germanium (Hpge) And Mercuric Iodide (Hgi2) Gamma Detectors, Michael B. Nelson Mar 2003

Detection Of Special Nuclear Material With High Purity Germanium (Hpge) And Mercuric Iodide (Hgi2) Gamma Detectors, Michael B. Nelson

Theses and Dissertations

The Defense Threat Reduction Agency (DTRA) contracted for two gamma radiation detectors: mercuric iodide (HgI2) and electromechanically cooled (EMC) high purity germanium (HPGe) to support arms control inspection efforts. This project investigated whether these detectors could measure the quality and quantity of special nuclear material (SNM), particularly Pu-239 for the treaty verification mission. The project investigated two areas of detector capabilities: 1) HgI2 and HPGe detector performance necessary to characterize the quality of plutonium and the presence of shielding materials and 2) HgI2 and EMC HPGe detector performance degradation by high noise levels and EMC HPGe …

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What The Universe Means To People Like Me, David D. Allred Mar 2003

What The Universe Means To People Like Me, David D. Allred

Faculty Publications

When I picked up David's paper to read it, I had a pencil in my hand. Years of reading my students' and my own papers made it natural to edit as I read. However, I heard in my mind the voice of my mother advising me to put the pencil down. This wasn't time to edit but to hear and understand. Still, I kept the pencil in my hand for the first few pages and made a few notes before I put it down and just read. I could hear David's voice speaking the words I read. It was good …

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Measurements Of Inelastic J/Ψ And Ψ′ Photoproduction At Hera, S. Chekanov, D. Krakauer, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi, G. Aghuzumtsyan, D. Bartsch, I. Brock Mar 2003

Measurements Of Inelastic J/Ψ And Ψ′ Photoproduction At Hera, S. Chekanov, D. Krakauer, S. Magill, B. Musgrave, J. Repond, R. Yoshida, Margarita C. K. Mattingly, P. Antonioli, G. Bari, M. Basile, L. Bellagamba, D. Boscherini, A. Bruni, G. Bruni, G. Cara Romeo, L. Cifarelli, F. Cindolo, A. Contin, M. Corradi, S. De Pasquale, P. Giusti, G. Iacobucci, A. Margotti, R. Nania, F. Palmonari, A. Pesci, G. Sartorelli, A. Zichichi, G. Aghuzumtsyan, D. Bartsch, I. Brock

Faculty Publications

The cross sections for inelastic photoproduction of J/ψ and ψ′ mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 38.0 pb-1. The events were required to have 0.1 < z < 0.9 and 50 < W < 180 GeV, where z is the fraction of the incident photon energy carried by the J/ψ in the proton rest frame and W is the photon-proton centre-of-mass energy. The ψ′ to J/ψ cross-section ratio was measured in the range 0.55 < z < 0.9. The J/ψ data, for various ranges of transverse momentum, are compared to theoretical models incorporating colour-singlet and colour-octet matrix elements. Predictions of a next-to-leading-order colour-singlet model give a good description of the data, although there is a large normalisation uncertainty. The J/ψ helicity distribution for z > 0.4 is compared to leading-order QCD predictions.

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Building Blocks For Time-Resolved Laser Emission In Mid-Infrared Quantum Well Lasers, Gabriel D. Mounce Mar 2003

Building Blocks For Time-Resolved Laser Emission In Mid-Infrared Quantum Well Lasers, Gabriel D. Mounce

Theses and Dissertations

The objective of this research is to improve the performance of mid-infrared semiconductor quantum-well lasers. Lasers operating in the mid-infrared are useful for many Air Force applications which include infrared (IR) countermeasures in particular. Countermeasure applications require lasers that are compact, and able to emit at high powers while operating at room temperature. Limits to power increases are seen in the transverse modal development of laser oscillation. These modes typically form in the waveguiding active region contributing to the laser output. However, competing modes outside of this region also develop when the confining structural layers have the right characteristics. These …

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Search For A W1 Boson Decaying To A Top And Bottom Quark Pair In 1.8 Tev Pp̅ Collisions, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration Feb 2003

Search For A W1 Boson Decaying To A Top And Bottom Quark Pair In 1.8 Tev Pp̅ Collisions, Darin Acosta, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report the results of a search for a W′ boson produced in pp̅ collisions at a center-of-mass energy of 1.8 TeV using a 106 pb-1 data sample recorded by the Collider Detector at Fermilab. We observe no significant excess of events above background for a W′ boson decaying to a top and bottom quark pair. In a model where this boson would mediate interactions involving a massive right-handed neutrino (νR) and have standard model strength couplings, we use these data to exclude a W′ boson with mass between 225 and 536 GeV/c2 at 95% …

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Anomalous Commutator Algebra For Conformal Quantum Mechanics, Horacio E. Camblong Feb 2003

Anomalous Commutator Algebra For Conformal Quantum Mechanics, Horacio E. Camblong

Physics and Astronomy

The structure of the commutator algebra for conformal quantum mechanics is considered. Specifically, it is shown that the emergence of a dimensional scale by renormalization implies the existence of an anomaly or quantum-mechanical symmetry breaking, which is explicitly displayed at the level of the generators of the SO(2,1) conformal group. Correspondingly, the associated breakdown of the conservation of the dilation and special conformal charges is derived.

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Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Darrell Pepper, Randy Clarksean Feb 2003

Design And Analysis Of A Process For Melt Casting Metallic Fuel Pins Incorporating Volatile Actinides, Yitung Chen, Darrell Pepper, Randy Clarksean

Fuels Campaign (TRP)

UNLV has developed and will continue to develop process models for the analysis of melt casting processes. This work will continue to be performed under the guidance of Argonne National Laboratory (ANL) engineers to insure that their knowledge and experience benefits the project. The research to be conducted during year three will center on performing detailed analyses on a conceptual design of an inductively heated skull-crucible casting furnace. Processing conditions will be analyzed, basic models utilized, and detailed heat and mass transfer models will be developed to analyze the most promising processes. The goal of this third year is to …

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