Physical Sciences and Mathematics Commons^™

The Pg X-Ray Qso Sample: Links Between The Ultraviolet-X-Ray Continuum And Emission Lines, Beverley J. Wills, A. Laor, M. S. Brotherton, D. Wills, B. J. Wilkes, Gary J. Ferland, Zhaohui Shang

Physics and Astronomy Faculty Publications

Two sets of relationships relate QSO UV to soft X-ray continua with the broad-line region. These are (i) the Baldwin relationships, which are inverse relationships between the broad-line equivalent width and the continuum luminosity, and (ii) Boroson & Green's optical "Principal Component 1'' relationships, linking steeper soft X-ray spectra with narrower Hβ emission, stronger Hβ blue wings, stronger optical Fe II emission, and weaker [O III] λ5007 lines. In order to understand these relationships, we extended the spectra into the UV for 22 QSOs with high-quality soft X-ray spectra. These are from the complete sample of QSOs from the Bright …

Natural Emissions Of Chlorine-Containing Gases: Reactive Chlorine Emissions Inventory, M. A. K. Khalil, R. M. Moore, D. B. Harper, J. M. Lobert, D. J. Erickson, V. Koropalov, W. T. Sturges, W. C. Keene

Physics Faculty Publications and Presentations

Although there are many chlorine-containing trace gases in the atmosphere, only those with atmospheric lifetimes of 2 years or fewer appear to have significant natural sources. The most abundant of these gases are methyl chloride, chloroform, dichloromethane, perchloroethylene, and trichloroethylene. Methyl chloride represents about 540 parts per trillion by volume (pptv) Cl, while the others together amount to about 120 pptv Cl. For methyl chloride and chloroform, both oceanic and land-based natural emissions have been identified. For the other gases, there is evidence of oceanic emissions, but the roles of the soils and land are not known and have not …

Incommensurate And Commensurate Antiferromagnetic Spin Fluctuations In Cr And Cr Alloys From Ab Initio Dynamical Spin Susceptibility Calculations, Duane D. Johnson, J. Pulter, B. Ginatempo, E. Bruno, J. B. Staunton

Duane D. Johnson

A scheme for making ab initio calculations of the dynamic paramagnetic spin susceptibilities of solids at finite temperatures is described. It is based on time-dependent density functional theory and employs an electronic multiple scattering formalism. Incommensurate and commensurate antiferromagnetic spin fluctuations in paramagnetic Cr and compositionally disordered Cr95V5 and Cr95Re5 alloys are studied together with the connection with the nesting of their Fermi surfaces. We find that the spin fluctuations can be described rather simply in terms of an overdamped oscillator model. Good agreement with inelastic neutron scattering data is obtained.

Search For Third-Generation Leptoquarks From Technicolor Models In Pp̅ Collisions At √S = 1.8 Tev, F. Abe, Kenneth A. Bloom, Collider Detector At Fermilab Collaboration

Kenneth Bloom Publications

We report the results of a search for technicolor using 110 pb^-1 of pp̅ collisions recorded by the Collider Detector at Fermilab (CDF). In technicolor models containing a technifamily, color-octet technirhos enhance the pair production of color-triplet technipions, which behave as third-generation leptoquarks. From our previously reported search for third-generation leptoquarks, we present constraints on the production of color-triplet technipions and color-octet technirhos as a function of their masses.

Structural And Magnetic Properties Of Nanocomposite Co:C Films, M. Yu, Yi Liu, David J. Sellmyer

David Sellmyer Publications

The structural and magnetic properties of Co:C nanocomposite films at room temperature were investigated as functions of annealing temperature, Co concentration, and film thickness. The as-deposited films, which were cosputtered from Co and C onto water-cooled glass substrates, are nonmagnetic amorphous Co–C alloys. Hexagonal-close-packed (hcp) Co grains are formed in 100 nm films annealed at 300 °C and most Co takes this structure when annealed at higher temperatures. The sizes of the Co grains range from 10 to 25 nm, with larger grain size resulting from higher annealing temperature and higher Co concentration. With the increase of annealing temperature and …

Activation Entropy, Activation Energy, And Magnetic Viscosity, Ralph Skomski, Roger D. Kirby, David J. Sellmyer

Roger Kirby Publications

Starting from an exact quantum-statistical description, the influence of the shape of the energy landscape on the magnetic viscosity is investigated. Magnetic phase-space analysis based on Kramers’ escape-rate theory of chemical reaction kinetics theory shows that the activation entropy associated with thermally activated hopping modifies the magnetic viscosity by reducing the attempt-frequency prefactor compared to an earlier prediction by Brown [W. F. Brown, Phys. Rev. 130, 1677 (1963)]. Energetic contributions are analyzed in terms of a model applicable to a range of coherent and noncoherent magnetization processes, and in the long-time limit deviations from the linear logarithmic magnetic-viscosity law are …

Enhancement Of Coercivity In Nanometer-Size Copt Crystallites, Sy_Hwang Liou, S. Huang, Elizabeth S. Klimek, Roger D. Kirby

Roger Kirby Publications

In this study, we showed that a magnetic coercivity (H_c) as high as 37 kOe was obtained in a CoPt thin film that contains separated nanometer-size CoPt crystallites. We prepared CoPt thin films with thicknesses of 5 and 175 nm by magnetron sputtering. After annealing in an Ar/H₂ atmosphere at temperatures from 650 to 750 °C for 3–12 h, we measured the magnetic properties and found that magnetic H_c relates to annealing temperature, annealing time and film thickness. From atomic force microscopy and magnetic force microscopy studies, the magnetic single domain size of CoPt is …

Effects Of Layer Thickness On Orientation Distribution And Magnetic Properties Of Cocrta/Cr Films, Z.S. Shan, H. Zeng, C.X. Zhu, M. Azarisooreh, K. Honardoost

David Sellmyer Publications

Evolution of orientation distribution of Co(110) crystal planes was determined by x-ray rocking curves. It has been found that: (i) The full-width at half maximum W of the Co(110) rocking curve decreases with both increasing Cr underlayer thickness d_cr, and increasing CoCrTa magnetic layer thickness d_co, especially in the thin layer regime. (ii) For the thin d_coregime, the interlayer diffusion between the Cr underlayer and the magnetic layer affects the rocking curves and magnetic properties significantly. (iii) Film magnetic properties, e.g., a significant jump in coercivity with increasing magnetic layer thickness in the thin …

Magnetic Hardening In SmcoX–Co Multilayers And Nanocomposites, J. Ping Liu, Yi Liu, Ralph Skomski, David J. Sellmyer

David Sellmyer Publications

SmCo_x–Co (x = 3.5, 4, and 5) nanostructured multilayers have been prepared by dc and rf sputtering. Magnetic hardening has been found in the as-deposited thin films. The effects of the Co and hard-phase layer thicknesses and the effect of the Cr underlayer have been studied. Further magnetic hardening has been achieved by heat treating the samples. A remarkable increase of the coercivity has been obtained in the nanocomposite films, with coercive force up to 40 kOe. Transmission electron microscopy, atomic force microscopy, and magnetic force microscopy observations have been performed to understand the nanostructure and the domain …

Effects Of Layer Thickness On Orientation Distribution And Magnetic Properties Of Cocrta/Cr Films, Z. S. Shan, H. Zeng, C. X. Zhu, M. Azarisooreh, K. Honardoost, Yi Liu, David J. Sellmyer

David Sellmyer Publications

No abstract provided.

Strain Dependence Of The Magnetic Properties Of Nm Fe Films On W(100), Axel Enders, D. Sander, J. Kirschner

Axel Enders Publications

The thickness dependence of the magneto-elastic coupling B₁, the intrinsic film stress, and the magnetic in-plane anisotropy K₄ of Fe films on W(100) are measured with an in situ combination of a highly sensitive optical deflection technique with magneto-optical Kerr-effect measurements. We find that both B₁ and K₄ depend strongly on the Fe film thickness. The thickness dependence of B₁ can be described by considering a second order magneto-elastic coupling constant D = GJ/m³ as a strain dependent correction of B₁. We tentatively ascribe the deviation of K₄ from its …

Magnetic And Structural Properties Of Mg–Co Nanostructures Fabricated, E.M. Kirkpatrick, Diandra Leslie-Pelecky, S.-H. Kim, R.D. Rieke

Diandra Leslie-Pelecky Publications

Reductive chemical synthesis is a versatile tool for fabricating elemental nanostructures; however, less work has been completed on understanding and controlling alloy formation. Magnetic Mg–Co and Mg–Co–C nanocomposites have been fabricated using a reductive chemical synthesis designed to produce highly active metals. The as-synthesized powder was annealed at temperatures from 150 to 650 °C. Samples were investigated using x-ray diffraction, alternating gradient force magnetometry, and superconducting quantum interference device magnetometry. X-ray diffraction indicates that the resulting structures are multiphase with MgCo₂, MgCo₃C0. ₅, fcc Co, Mg, MgO, and Li₂CO₃ present depending on …

Dielectric Tensor For Magneto-Optic Nimnsb, Xiang Gao, John A. Woollam, Roger D. Kirby, David J. Sellmyer, C. T. Tanaka, J. Nowak, Jagadeesh S. Moodera

Department of Physics and Astronomy: Faculty Publications

The diagonal component ɛ_xx and off-diagonal component ɛ_xy of the complex dielectric tensor for the ferromagnetic compound NiMnSb are determined using ex situ spectroscopic ellipsometry and magneto-optic analysis over the spectral range from 0.7 to 6.2 eV. The effects of the overcoat on the raw data are removed by the analysis. First, the complex ɛ_xx of thin-film NiMnSb were determined by ex situ spectroscopic ellipsometry; then ɛ_xy was determined by analyzing Kerr rotation and ellipticity data using the determined ɛ_xy data. Lorentz oscillators were used to model peaks seen in the ɛ_xx spectra. The …

Lake Whatcom Monitoring Project 1997/1998 Report, Robin A. Matthews, Michael Hilles, Geoffrey B. Matthews

Lake Whatcom Annual Reports

This report is part of an on-going series of annual reports and special project reports that document the Lake Whatcom monitoring program.

This work is conducted by the Institute for Watershed Studies and other departments at Western Washington University. The major objective of this program is to provide long-term baseline water quality monitoring in Lake Whatcom and selected tributaries. Each section contains brief explanations about the water quality data, along with discussions of patterns observed in Lake Whatcom.

Poc Production And Export In The Indian Ocean Sector Of The Southern Ocean: A Us-China Collaborative Research Program, Cynthia H. Pilskaln, Fei Chai

University of Maine Office of Research Administration: Grant Reports

This proposed work is a study of the biological production and export flux of biogenic matter in response to ventilation of intermediate and deep water masses within the Polar Front zone. It is a collaborative work between the University of Maine and the Chinese Antarctic Research Expedition (CHINARE). The shipboard work is proposed for the Chinese antarctic resupply vessel off Prydz Bay in the Indian Ocean sector. In the austral Spring, this region experiences phytoplankton blooms that are thought to be the result of nutrient transport by the ventilation of intermediate and deep water masses. On an annual basis, it …

K-Inflation, Christian Armendariz-Picon, T. Damour, V. Mukhanov

Physics - All Scholarship

It is shown that a large class of higher-order (i.e. non-quadratic) scalar kinetic terms can, without the help of potential terms, drive an inflationary evolution starting from rather generic initial conditions. In many models, this kinetically driven inflation (or "k-inflation" for short) rolls slowly from a high-curvature initial phase, down to a low-curvature phase and can exit inflation to end up being radiation-dominated, in a naturally graceful manner. We hope that this novel inflation mechanism might be useful in suggesting new ways of reconciling the string dilaton with inflation

An Examination Of Codewords With Optimal Merit Factor, Michael W. Cammarano, Anthony G. Kirilusha

Department of Math & Statistics Technical Report Series

We examine the codewords with best possible merit factor (minimum sum of squares of periodic autocorrelations) for a variety of lengths. Many different approaches were tried in an attempt to find construction methods for such codewords, or for codewords with good but non-optimal merit factors.

Airport Bird Threat In North America From Large Flocking Birds (Geese) (As Viewed By An Engine Manufacturer)--Part 1, Thomas Alge

Bird Strike Committee-USA/Canada Joint Annual Meeting: 1st (1999)

In worldwide aviation operations, bird collisions with aircraft and ingestions into engine inlets present safety hazards and financial loss through equipment damage, loss of service and disruption to operations. The problem is encountered by all types of aircraft, both military and commercial. Modern aircraft engines have achieved a high level of reliability while manufacturers and users continually strive to further improve the safety record. A major safety concern today includes common-cause events which involve significant power loss on more than one engine. These are externally-inflicted occurrences, with the most frequent being encounters with flocks of birds. Most frequently these encounters …

Integer Maxima In Power Envelopes Of Golay Codewords, Michael W. Cammarano, Meredith L. Walker

Department of Math & Statistics Technical Report Series

This paper examines the distribution of integer peaks amoung Golay cosets in Ζ_4. It will prove that the envelope power of at least one element of every Golay coset of Ζ₄ of length 2^m (for m-even) will have a maximum at exactly 2^m+1. Similarly it will be proven that one element of every Golay coset of Ζ₄ of length 2^m (for m-odd) will have a maximum at exactly 2^m+1. Observations and partial arguments will be made about why Golay cosets of Ζ₄ of length 2^{m …}

Output Control Of Vertical Microcavity Light Emitting Device, James A. Lott

AFIT Patents

An improved intracavity sensor based output power control for microcavity light emitting devices. An improved phototransistor transducer is both configured and physically disposed so that it passively transmits the spurious optical energy output of the microcavity light emitting device while simultaneously generating a light determined electrical signal of easily used large magnitude that is nearly free of error. The base-collector region of the transistor is disposed with a quantum well absorbing layer and produces a signal responsive to a selected emission wavelength. The configuration of the optical energy communicating transducer is arranged so that it is improved in sensitivity and …

Applications Of Amorphous Track Models In Radiation Biology, Francis Cucinotta, Hooshang Nikjoo, Dudley A. Goodhead

Robert Katz Publications

The average or amorphous track model uses the response of a system to gamma-rays and the radial distribution of dose about an ion’s path to describe survival and other cellular endpoints from proton, heavy ion, and neutron irradiation. This model has been used for over 30 years to successfully fit many radiobiology data sets. We review several extensions of this approach that address objections to the original model, and consider applications of interest in radiobiology and space radiation risk assessment. In the light of present views of important cellular targets, the role of target size as manifested through the relative …

Water Current, Volume 31, No. 2, April 1999

Water Current Newsletter

Defining Visions of Nebraska's Water Future
From the Director
Jess, Harnsberger, "Nebraska Plan" Team Honored as Water Stewards at Kearney
University of Nebraska Hires Jess
Nebraska Forestry Shortcourse
Managing Pesticides to Minimize Risk
Water News Brief
Free Drinking Water Week Packets
AWWA Announces Research Project Funds
TGF Memberships
Nebraska Water Tour

A Calibration Procedure Using Topmodel To Determine Suitability For Evaluating Potential Climate Change Effects On Water Yield, Brian Dietterick, James A. Lynch, Edward S. Corbett

Natural Resources Management and Environmental Sciences

An evaluation was conducted on three forested upland watersheds in the northeastern U.S. to test the suitability of TOPMODEL for predicting water yield over a wide range of climatic scenarios. The analysis provides insight of the usefulness of TOPMODEL as a predictive tool for future assessments of potential long-term changes in water yield as a result of changes in global climate. The evaluation was conducted by developing a calibration procedure to simulate a range of climatic extremes using historical temperature, precipitation, and streamfiow records for years having wet, average, and dry precipitation amounts from the Leading Ridge (Pennsylvania), Fernow (West …

The Dynamics Of Cyberspace: Examining And Modelling Online Social Structure, Brian S. Butler '89

Doctoral Dissertations

It has been proposed that online social structures represent new forms of organizing which are fundamentally different from traditional social structures. However, while there is a growing body of empirical research that considers behavioral aspects of online activity, research on online social structure structural remains largely anecdotal. This work consists of three papers that combine previous studies of traditional social structures, empirical analysis of longitudinal data from a sample of Internet listservs, and computational modeling to examine the dynamics of social structure development in networked environments.

The first paper (Title: When is a Group not a Group: An Empirical Examination …

Aluminum And Phosphorus Separation: Application To Preparation Of Target From Brain Tissue For 26Al Determination By Accelerator Mass Spectrometry, Russell D. Brauer, J. David Robertson, Pankaj Sharma, Robert A. Yokel

Pharmaceutical Sciences Faculty Publications

Acid digested brain containing 4 mg added ²⁷Al was ashed at 1000°C to prepare an Al₂O₃ target for accelerator mass spectrometry (AMS) analysis of ²⁶Al. A glass-like material usually resulted which was thought to be aluminum (Al) oxyphosphate. The separation of Al and phosphate was investigated. Al, but not phosphate, was bound by a cation exchange resin (AG 50-X8). Hydrofluoric acid eluted the Al from the resin. Removal of phosphate from acid digested brain by this method produced an amorphous material after ashing that was easier to recover from the porcelain crucible and had a …

Reviews Of Atomic Audit: The Costs And Consequences Of Us Nuclear Weapons Since 1940 By Stephen Schwartz; And Killing Detente: The Right Attacks The Cia By Anne Cahn, David W. Hafemeister

Physics

Science aims to link cause and effect for natural phenomena. Linking cause and effect for historical events is often more difficult since historical events cannot be tested by rerunning history with varied parameters. Despite the difficulty, it is worthwhile to review the causes behind the magnitude of the U.S. nuclear buildup. Two critical questions should guide this analysis: How much of the $5.8 trillion (1996 dollars) that the U.S spent to build 70,000 nuclear warheads, deployed on 75,000 missiles and 8600 bombers, was too much? And, was the effectiveness of the Soviet military exaggerated with false predictions? These two books …

Circulation, Vol. 6, No. 3, Center For Coastal Physical Oceanography, Old Dominion University

CCPO Circulation

Spring 1999 issue of CCPO Circulation featuring article "Studying Earth's Environment from Space"

Characterization And Identification Of A Sludge-Associated Bacterial Isolate, Abiodun O. Adibi, Derrell Mcpherson, Minna Laine

Virginia Journal of Science

During a metal speciation study, an unusually high retention of lead ·was observed when lead solution was percolated through a column packed with sludge compost obtained from Hampton Roads Sanitation department. A bacterium was isolated from the sludge compost and identified as Bacillus sphaericus using electron microscopy, whole cell fatty acid analysis (Midi System) and Biolog GP Microplate. The isolate grows in broth and agar media containing up to 800 µM lead. Lead accumulation study using atomic absorption spectrophotometer indicates that the isolate adsorbs lead. Lead adsorption is pH dependent. The isolate contains a plasmid of approximately 40 -50 kbp …

Synthesis And Crystal Structure Of Tetrachloro (1,10-Phenanthroline) Platinum (Iv), Robert M. Granger Ii, Jill N. Granger, Kelly Del Campo, Molly B. Becherer, Phillip E. Fanwick

Virginia Journal of Science

We report the crystal structure determination of tetrachloro( l,10-phenan­throline)platinum(IV). X-ray data indicate there is little steric repulsion between the cx.-hydrogens on the phenanthroline ligand and the chloride ligands in the equatorial plane.

Wright State University College Of Engineering And Computer Science Bits And Pcs Newsletter, Volume 15, Number 4, April 1999, College Of Engineering And Computer Science, Wright State University

BITs and PCs Newsletter

An eight page newsletter created by the Wright State University College of Engineering and Computer Science that addresses the current affairs of the college.