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1996

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Articles 421 - 450 of 2437

Full-Text Articles in Physical Sciences and Mathematics

Existence And Bifurcation Of The Positive Solutions For A Semilinear Equation With Critical Exponent, Yinbin Deng, Yi Li Sep 1996

Existence And Bifurcation Of The Positive Solutions For A Semilinear Equation With Critical Exponent, Yinbin Deng, Yi Li

Mathematics and Statistics Faculty Publications

In this paper, we consider the semilinear elliptic equation[formula]Forp=2N/(N−2), we show that there exists a positive constantμ*>0 such that (∗)μpossesses at least one solution ifμ∈(0, μ*) and no solutions ifμ>μ*. Furthermore, (∗)μpossesses a unique solution whenμ=μ*, and at least two solutions whenμ∈(0, μ*) and 2<NN⩾6, under some monotonicity conditions onf((1.6)) we show that there exist two constants 0<μ**⩽μ**<μ* such that problem (∗)μ …

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In-Situ Far-Field Calibration Of Multibeam Sonar Arrays For Precise Backscatter Imagery, Larry Fusillo, Christian De Moustier, John H. Satriano, Stanley Zietz Sep 1996

In-Situ Far-Field Calibration Of Multibeam Sonar Arrays For Precise Backscatter Imagery, Larry Fusillo, Christian De Moustier, John H. Satriano, Stanley Zietz

Center for Coastal and Ocean Mapping

Calibration of large hull-mounted sonar transducer arrays is usually done by measuring the performance of individual components in a test tank. Multiple transducer element beam patterns are superimposed and combined with window attenuation and other partial measurements to give an approximation of the total beam pattern. This process often ignores or fails to accurately model factors such as mounting hardware, array misalignment, reflections from the hull structure and other real world absorbers, reflectors and attenuators which can have significant effect on the actual beam pattern. This paper describes an application of a novel technique for in-situ measurement of the far-field …

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Analysis Of An Asymmetric Leader Election Algorithm, Svante Janson, Wojciech Szpankowski Sep 1996

Analysis Of An Asymmetric Leader Election Algorithm, Svante Janson, Wojciech Szpankowski

Department of Computer Science Technical Reports

No abstract provided.

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Use Of A Taxonomy Of Security Faults, Taimur Aslam, Ivan Krsul, Eugene H. Spafford Sep 1996

Use Of A Taxonomy Of Security Faults, Taimur Aslam, Ivan Krsul, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

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Idiot - Users Guide, Mark Crosbie, Bryn Dole, Todd Ellis, Ivan Krsul, Eugene H. Spafford Sep 1996

Idiot - Users Guide, Mark Crosbie, Bryn Dole, Todd Ellis, Ivan Krsul, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

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Authorship Analysis: Identifying The Author Of A Program, Ivan Krsul, Eugene H. Spafford Sep 1996

Authorship Analysis: Identifying The Author Of A Program, Ivan Krsul, Eugene H. Spafford

Department of Computer Science Technical Reports

No abstract provided.

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Mccogen, A C Code Generator From Mathematica Language, Chang-Hyeon Song Sep 1996

Mccogen, A C Code Generator From Mathematica Language, Chang-Hyeon Song

Department of Computer Science Technical Reports

No abstract provided.

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Applications Of A Numbering Scheme For Polygonal Obstacles In The Plane, Mikhail J. Atallah, Danny Z. Chen Sep 1996

Applications Of A Numbering Scheme For Polygonal Obstacles In The Plane, Mikhail J. Atallah, Danny Z. Chen

Department of Computer Science Technical Reports

No abstract provided.

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Parallel Reuse Methodologies For Elliptic Boundary Value Problems, S. Markus, Elias N. Houstis Sep 1996

Parallel Reuse Methodologies For Elliptic Boundary Value Problems, S. Markus, Elias N. Houstis

Department of Computer Science Technical Reports

No abstract provided.

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Multi-Pass Transmission Policy: An Effective Method Of Transmitting Large Multimedia Objects In The Wide-Area Network, Sheng-Yih Wang, Bharat Bhargava Sep 1996

Multi-Pass Transmission Policy: An Effective Method Of Transmitting Large Multimedia Objects In The Wide-Area Network, Sheng-Yih Wang, Bharat Bhargava

Department of Computer Science Technical Reports

No abstract provided.

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Simple Measurement Of 300 K Electron Capture Cross Section For El2 In Gaas, David C. Look, Z-Q. Fang Sep 1996

Simple Measurement Of 300 K Electron Capture Cross Section For El2 In Gaas, David C. Look, Z-Q. Fang

Physics Faculty Publications

A simple experiment involving only the measurement of dark current Idark and 1.1 μm photocurrent IPC in semi‐insulating (SI) GaAs allows an accurate determination of the electron capture cross section σn for the important defect EL2 in GaAs. For 45 SI GaAs samples, from 12 different boules, grown by three different techniques, we find that IPC/Idark=1.96±0.05 at 300 K. This relationship gives σn=1.4±0.4×10−16 cm2, which is compared to previously estimated values.

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Deep-Center Hopping Conduction In Gan, David C. Look, D. C. Reynolds, W. Kim, Ö. Aktas, A. Botchkarev, A. Salvador, H. Morkoç Sep 1996

Deep-Center Hopping Conduction In Gan, David C. Look, D. C. Reynolds, W. Kim, Ö. Aktas, A. Botchkarev, A. Salvador, H. Morkoç

Physics Faculty Publications

Molecular‐beam‐epitaxial GaN layers change from strongly conductive (ρ≂10−2 Ω cm at 300 K) to semi‐insulating (ρ≂106 Ω cm) as the N flux is increased. Layers grown at low fluxes show strong n‐type conduction, with transport in the conduction band at high temperatures and in a shallow donor band at low temperatures. For layers grown at high N fluxes, the Hall coefficients become too small to measure, suggesting hopping conduction among deep centers. The temperature‐dependent resistivity data are most consistent with multiphonon, rather than single‐phonon, hopping.

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Residency Check Elimination For Object- Oriented Persistent Languages, Antony L. Hosking Sep 1996

Residency Check Elimination For Object- Oriented Persistent Languages, Antony L. Hosking

Department of Computer Science Technical Reports

No abstract provided.

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Determination Of Crystal-Field Parameters Of Sm2Fe17N3 And Sm2Fe17C3, S. Wirth, M. Wolf, K.H. Muller, Ralph Skomski, S. Brennan, J.M.D. Coey Sep 1996

Determination Of Crystal-Field Parameters Of Sm2Fe17N3 And Sm2Fe17C3, S. Wirth, M. Wolf, K.H. Muller, Ralph Skomski, S. Brennan, J.M.D. Coey

Ralph Skomski Publications

The crystal-field parameters A20 and A40 were determined from the magnetocrystalline anisotropy constants K1 and K2 in a linear approximation for Sm2Fe17Zx (Z = N, C) compounds. For the materials investigated, the values of Iη0 are calculated in two ways: i) from the Kί at zero temperature and ii) from the temperature dependence of the Kί. Both methods give equivalent results. The value A20≈-400 Ka0-2 has been obtained which corresponds to an inverse THOMAS-FERMI screening length q≈2.3 Å-1 calculated within the framework …

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Is There Spin-Glass Exchange In Ultrathin Fe(110) Films ?, Ralph Skomski, D. Sander, Axel Enders, J. Kirschner Sep 1996

Is There Spin-Glass Exchange In Ultrathin Fe(110) Films ?, Ralph Skomski, D. Sander, Axel Enders, J. Kirschner

Ralph Skomski Publications

The magnetism of sesquilayer bcc iron films on W(110) is investigated. Coercivity data and theoretical calculations that the freezing of the magnetization at low temperatures reflects exchange-dominated domain-wall pinning rather than superparamagnetic spin-glass behavior.

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Film Stress And Domain Wall Pinning In Sesquilayer Iron Films On W(110), D. Sander, Ralph Skomski, C. Schmidthals, Axel Enders, J. Kirschner Sep 1996

Film Stress And Domain Wall Pinning In Sesquilayer Iron Films On W(110), D. Sander, Ralph Skomski, C. Schmidthals, Axel Enders, J. Kirschner

Ralph Skomski Publications

We present an in situ investigation of the correlation between elastic and magnetic properties of monolayer iron films on W(110). Sesquilayers, consisting of two-monolayer patches on a nearly ideal monolayer film, exhibit anomalous elastic properties and a strikingly high in-plane coercivity of order 0.3 T. The sesquilayer coercivity maximum is explained by a novel domain wall pinning mechanism, based on an enhanced exchange interaction in the two monolayer thick patches. This rather unique behavior is restricted to (110) surfaces but does not occur on (100) and (111) thin films.

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Review Of: Peter K. Lagoy, Risk Assessment: Principles And Applications For Hazardous Waste And Related Sites (Noyes Publications 1994), Adam K. Sacharoff Sep 1996

Review Of: Peter K. Lagoy, Risk Assessment: Principles And Applications For Hazardous Waste And Related Sites (Noyes Publications 1994), Adam K. Sacharoff

RISK: Health, Safety & Environment (1990-2002)

Review of the book: Peter K. LaGoy, Risk Assessment: Principles and Applications for Hazardous Waste and Related Sites (Noyes Publications 1994). Appendices, figures, index, notes, preface, references, tables. LC 94-2510; ISBN 0-8155-1349-6. [260 pp. Cloth $48.00. 120 Mill Road, Park Ridge NJ 07656.]

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Table Of Contents Volume Seven, Number Four, Fall 1996, Risk Editorial Board Sep 1996

Table Of Contents Volume Seven, Number Four, Fall 1996, Risk Editorial Board

RISK: Health, Safety & Environment (1990-2002)

Table of contents for the journal RISK: Health, Safety & Environment (ISSN: 1073-8673). Includes announcement for the First Biennial International Meeting of the Risk Assessment & Policy Association (RAPA) held in Alexandria, Virginia.

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Review Of: Science Advice To The President (William T. Golden, Ed. Aaas Press 2d Ed. 1993)., Timothy Van Dyke Sep 1996

Review Of: Science Advice To The President (William T. Golden, Ed. Aaas Press 2d Ed. 1993)., Timothy Van Dyke

RISK: Health, Safety & Environment (1990-2002)

Review of: Science Advice to the President (William T. Golden, ed. AAAS Press 2d Ed. 1993). Acknowledgments, index of names, introductions, notes, tables. ISBN 0-87168-509-4 [340 pp. $29.95 paper. American Association for the Advancement of Science, 1333 H St. NW, Washington DC 20701.]

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Theory Of The Seebeck Coefficient In Lacro₃ And Related Perovskite Systems, D. B. Marsh, Paul Ernest Parris Sep 1996

Theory Of The Seebeck Coefficient In Lacro₃ And Related Perovskite Systems, D. B. Marsh, Paul Ernest Parris

Physics Faculty Research & Creative Works

We consider the Seebeck coefficient in LaCrO3 and related transition-metal-oxide perovskites using a model for electronic conduction based on the electronic structure of the 3d orbitals of the B-site transition-metal cations. Relations for the Seebeck coefficient are presented for those perovskite systems in which electronic conduction is through the t2g states of the B-site transition-metal cations. High- and low-temperature limits for the Seebeck coefficient are identified for the cases of both strong and weak magnetic coupling between electron spins. In these high- and low-temperature limits, the Seebeck coefficient is determined as a function of carrier concentration. Results are …

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High Coercivity Smfesic Films Fabricated By Multilayer Sputtering, S.Y. Zhang, Z.S. Shan, Yi Liu, David J. Sellmyer Sep 1996

High Coercivity Smfesic Films Fabricated By Multilayer Sputtering, S.Y. Zhang, Z.S. Shan, Yi Liu, David J. Sellmyer

David Sellmyer Publications

SmFeSiC thin films have been obtained by sputtering SmFe/C(Si) multilayers with a Ta underlayer on Si substrates and subsequently annealing at 700° C. The coercivity of the SmF films strongly depends on the sputtering and annealing conditions. The influence of the thickness of the Ta underlayer, the thickness ratio of SmFe to C(Si), the argon pressure and heat treatment In- plane Coercivities up to 7.2 kOe and squareness of 0.94 were obtained.

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Lorentz Microscopy Observation Of Magnetic Grains In Co-Sm // Cr Films, Yi Liu, Z.S. Shan, David J. Sellmyer Sep 1996

Lorentz Microscopy Observation Of Magnetic Grains In Co-Sm // Cr Films, Yi Liu, Z.S. Shan, David J. Sellmyer

David Sellmyer Publications

This paper presents our recent Lorentz microscopy study of magnetic domain structure and its relation to the nanostructure of Co-Sm films. The magnetic domains were imaged by Foucault Lorentz mode and the corresponding nanostructure was revealed by bright field and high resolution images. The nanostructure is composed of clusters of 20 nm grown on Cr grains. Each cluster is formed by the amorphous matrix and about 5 nm crystallites distributed in the matrix. It is found that each cluster forms a magnetic grain. Such magnetic grains show uniform contrast near the magnetic domain wall, and correspond to the switching volume …

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Proton Spin-Lattice Relaxation Of Water Molecules In Ferrous-Ferric/Agarose Gel System, Tadashi Tokuhiro, Alan Appleby, Armin A. Leghrouz, Rodney Metcalf, Robert Tokarz Sep 1996

Proton Spin-Lattice Relaxation Of Water Molecules In Ferrous-Ferric/Agarose Gel System, Tadashi Tokuhiro, Alan Appleby, Armin A. Leghrouz, Rodney Metcalf, Robert Tokarz

Chemistry Faculty Research & Creative Works

Proton spin-lattice relaxation time (T1) of water in aqueous solutions of ferrous and ferric ions and in the corresponding agarose gel systems have been studied in the light of NMR relaxation theory. The theoretical analysis of 1/T1's has revealed that, at the microscopic level, changes in the solvation states of paramagnetic ions in aqueous or gel environment are greater than difference in the paramagnetism between ferric and ferrous ions. The former change is the primary factor for the exhibition of radiation effect. At the phenomenological level, we have confirmed and demonstrated that: (1) Radiation effect is …

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An Effective-Viscosity Description Of Domain-Wall Motion In Magnetic Thin Films With Perpendicular Anisotropy, Ralph Skomski, J. Giergiel, J. Kirschner Sep 1996

An Effective-Viscosity Description Of Domain-Wall Motion In Magnetic Thin Films With Perpendicular Anisotropy, Ralph Skomski, J. Giergiel, J. Kirschner

Ralph Skomski Publications

The expansion of magnetic domains in thin films with perpendicular anisotropy is investigated. To determine the domain-wall velocity as a function of the applied magnetic field a self-=consistent magnetic-viscosity approach is used. The main predictions of the theory are a linear behavior\r in the limit of moderately strong fields, a quasi-exponential behavior for fields close to the propagation field, and a negative velocity for very small and negative fields. The predictions of the theory are compatible with domain-wall investigations on Au/Co/Au sandwiches.

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High Coercive Field And Film Stress For Epitaxial Monolayers Of Fe On W(110), D. Sander, Axel Enders, Ralph Skomski, J. Kirschner Sep 1996

High Coercive Field And Film Stress For Epitaxial Monolayers Of Fe On W(110), D. Sander, Axel Enders, Ralph Skomski, J. Kirschner

Ralph Skomski Publications

Elastic and magnetic properties of ultra-thin iron films on tungsten(110) are investigated. In situ film stress measurements during growth show stress values of 25 GPa per deposited monolayer. Our experiments indicate that the tremendous film stress triggers the formation of a misfit dislocation network at a coverage of 1.5 monolayers. The effect of the film stress and its spatial variation on the magnetic behavior are discussed. We find an high coercivity of order 0.3 T for 1.5 monolayer thick films. A model is presented that explains the high coercivity in terms of strong domain wall pinning.

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The Itinerant Limit Of Metallic Anisotropy, Ralph Skomski Sep 1996

The Itinerant Limit Of Metallic Anisotropy, Ralph Skomski

Ralph Skomski Publications

The anisotropy contribution of itinerant electrons confined to a quantum-well potential is calculated and compared with the quasi-ionic contribution due to virtually bound electrons. The easy magnetization direction of the non-L-S quantum-well electrons lies in the plane, and the magnitude of the anisotropy, maximally of order 10 J/m3, is too weak to explain anisotropies encountered in practice. This means that itinerant 3d anisotropy in bulk materials and thin films is associated with Hund's rules-type ionic Contributions.

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First Results From The High-Brightness X-Ray Spectroscopy Beamline 9.3.1 At Als, W. Ng, G. Jones, Rupert C. Perera, D. Hansen, J. Daniels, Oliver Hemmers, P. Glans, S. B. Whitfield, H. Wang, Dennis W. Lindle Sep 1996

First Results From The High-Brightness X-Ray Spectroscopy Beamline 9.3.1 At Als, W. Ng, G. Jones, Rupert C. Perera, D. Hansen, J. Daniels, Oliver Hemmers, P. Glans, S. B. Whitfield, H. Wang, Dennis W. Lindle

Environmental Studies Faculty Publications

Beamline 9.3.1 at the Advanced Light Source (ALS) is a windowless beamline, covering the 1–6 keV photon energy range. This beamline is designed to achieve the goal of high brightness at the sample for use in the x‐ray atomic and molecular spectroscopy (XAMS) science, surface and interface science, biology and x‐ray optical development programs at ALS. X‐ray absorption and time‐of‐flight photoemission measurements in 2–5 keV photon energy range along with the flux, resolution, spot size and stability of the beamline will be discussed. Prospects for future XAMS measurements will also be presented.

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Kinetic-Energy- And Angular-Resolved Fragmentation Of Co In Vibrational-Resolved C 1s Excitation, N. Saito, Franz Heiser, Oliver Hemmers, K. Wieliczek, J. Viefhaus, U. Becker Sep 1996

Kinetic-Energy- And Angular-Resolved Fragmentation Of Co In Vibrational-Resolved C 1s Excitation, N. Saito, Franz Heiser, Oliver Hemmers, K. Wieliczek, J. Viefhaus, U. Becker

Environmental Studies Faculty Publications

Angular distributions of C++O+ from CO were measured, following vibrationally resolved C 1s excitations into the 2pπ, 3sσ, and 3pπ orbitals as well as into higher unresolved orbitals. A time-of-flight mass spectrometer, with a multihit-type position-sensitive anode, was used for the measurements. The anisotropy parameters (β) of C++O+ approach their theoretically expected values as the released kinetic energy in the fragmentation increases. The value of the β parameters remains constant for all vibrational states within each orbital.

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Pattern Formation And Evolution Near Autocatalytic Reaction Fronts In A Narrow Vertical Slab, J. Huang, Boyd F. Edwards Sep 1996

Pattern Formation And Evolution Near Autocatalytic Reaction Fronts In A Narrow Vertical Slab, J. Huang, Boyd F. Edwards

All Physics Faculty Publications

Linear analysis and nonlinear numerical simulations of autocatalytic reaction fronts ascending in narrow vertically unbounded slabs describe the growth, development, and annihilation of fingers in the front, the dynamics of edge suppression, and a secondary transition to a two-roll state above the onset of convection. The pattern formation and evolution of the reaction fronts are determined by the horizontal aspect ratio Γ=b/a and the dimensionless driving parameter S=δga3/νDC, which involve the gap thickness a, the slab width b, the fractional density difference δ between the unreacted and reacted solutions, the gravitational acceleration g, the kinematic viscosity …

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Sharing Common Ground On Western Rangelands: Proceedings Of A Livestock/Big Game Symposium, Keith E. Evans, Intermountain Research Station, Usdsa Forest Service, U.S. Department Of Commerce, United States Department Of Agriculture, Forest Service Sep 1996

Sharing Common Ground On Western Rangelands: Proceedings Of A Livestock/Big Game Symposium, Keith E. Evans, Intermountain Research Station, Usdsa Forest Service, U.S. Department Of Commerce, United States Department Of Agriculture, Forest Service

All U.S. Government Documents (Utah Regional Depository)

This proceedings includes 37 papers and posters presented at the "Sharing Common Ground" symposium. The information represents the progress made in livestock/big game management since the 1991 symposium with the theme of "Seeking Common Ground." The broad range of topics includes the rangeland resource, the science of livestock/big game interactions, the human dimension, and the success stories from the seeking common ground partnership demonstration projects.

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