Physical Sciences and Mathematics Commons^™

Relaxation Time Of The Order Parameter In A High-Temperature Superconductor, G.L. Eesley, J. Heremans, M.S. Meyer, G.L. Doll, Sy_Hwang Liou

Sy-Hwang Liou Publications

We present femtosecond time-resolved measurements on the high-T_c superconductor Tl₂Ba₂Ca₂Cu₃O₁₀. At temperatures below T_c, we observe a relaxation process which is distinct from the equilibration of hot carriers in the normal state. Our results demonstrate an increasing relaxation rate as the superconducting gap opens. This is consistent with the behavior of conventional metallic superconductors.

Laser Cvd And Plasma Cvd Of Cro2 Films And Cobalt Doped Cro2 Films Using Organometallic Precursors, Peter A. Dowben, Marshall Onellion

Peter Dowben Publications

Chromium dioxide is deposited as a ferromagnetic layer onto selected portions of a substrate or over the entire substrate. Chromium hexacarbonyl vapor is introduced into a vacuum deposition chamber at e.g. 10 milliTorr and oxygen is introduced at e.g. 15 to 100 milliTorr. A UV laser beam is focused onto the substrate to form the CrO₂ layer photolytically. The CrO₂ layer can also be deposited by RF plasma deposition. This technique can also be employed for depositing MoC₂, WC₂, Mo_2φ3, MoO₂ or WO₂. Magnetic recording or memory devices are …

The Relationship Of The Virtual Orbitals Of Self-Consistent-Field Theory To Temporary Negative Ions In Electron Scattering From Molecules, Donghai Chen, Gordon A. Gallup

Gordon Gallup Publications

The theory given here shows how certain of the virtual orbitals of self-consistent field (SCF) theory provide a natural ingredient for constructing basis functions to study the shape resonances associated with temporary molecular ions. We give specific calculations of resonant behavior in H₂, N₂, ethylene, cyclopropene, and cyclobutene. In addition, we show how the theory can rationalize the relationship between Koopmans' theorem values of the energy of a resonance and the experimental values. The Journal of Chemical Physics is copyrighted by The American Institute of Physics.

A Report On Black-Tailed Prairie Dogs In Nebraska-- Their Biology, Behavior, Ecology, Management, And Responses To A Visual Barrier Fence, Nancy S. Foster

School of Natural Resources: Dissertations, Theses, and Student Research

I examined the effects of a visual barrier fence, which had a see-through visibility of 600/0, on the foraging, vigilance, and aggressive behaviors of adult female black-tailed prairie dogs from June through August 1990 in central Nebraska. I also examined changes in their home ranges and use of an area in response to this fence. Prairie dogs prefer an open view of their surroundings. Therefore, I expected animals near a visual barrier to spend more time in vigilance and aggression, and less time foraging. Adult female prairie dogs exposed to the visual barrier devoted more time to foraging and less …

Magnetism Of Rare-Earth–Transition-Metal Nanoscale Multilayers. Ii. Theoretical Analysis Of Magnetization And Perpendicular Magnetic Anisotropy, Z.S. Shan, David J. Sellmyer, Sitaram Jaswal, Y.J. Wang, J.X. Shen

David Sellmyer Publications

Systematic studies of rare-earth–transition-metal amorphous compositionally modulated films (CMF) permit the development of a detailed model for understanding the magnetization and perpendicular magnetic anisotropy and their distributions along the film normal. It is shown that the single-ion anisotropy of rare-earth ions with orbital angular momentum is the major contributor to the perpendicular anisotropy for this class of CMF. The calculated results agree well with the experimental data for Dy/Co and Tb/Fe CMF when the individual layer thicknesses are small enough (<10 Å); these films have structures which can be characterized as compositionally modulated amorphous alloys.

Magnetism Of Rare-Earth–Transition-Metal Nanoscale Multilayers. I. Experiments On Dy/Co, Dy/Fe, And Tb/Fe, Z.S. Shan, David J. Sellmyer

David Sellmyer Publications

Experimental investigations of magnetic and structural properties for rare-earth–transition-metal (RE-TM) compositionally modulated films (CMF) are presented in this paper. In particular, A^RE/B^TM including A^RE=Dy and Tb and B^TM=Fe, Co, and Ni, are studied. The layer thickness and temperature dependence of magnetic properties, which can be interpreted in terms of the antiferromagnetic coupling of RE and TM moments and their atomic distributions, are reported. These A^RE/B^TM CMF with nanoscale layer thicknesses exhibit perpendicular magnetic anisotropy (PMA) and the range of the layer thickness required for PMA is determined. The …

The Probe, Issue 106 - December 1990

The Probe: Newsletter of the National Animal Damage Control Association

THE PROBE
National Animal Damage Control Association
DECEMBER 1990
Message from the President
NADCA Membership Meeting in Lincoln
1990 NADCA Membership Directory

The Prairie Naturalist Volume 22, No. 4. December 1990

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

DISTRIBUTION AND STATUS OF GREATER PRAIRIE-CHICKENS IN COLORADO ▪ B. F. Van Sant and C. E. Braun

IMPORTANCE OF AN OLD, MULTIPLE-USE RESERVOIR TO MIGRATING AND WINTERING DABBLING DUCKS ▪ D. M. Leslie, Jr. , and W. J. Stancill

SIMILARITY OF MALLARD NESTING ON A SOUTH DAKOTA ISLAND BETWEEN 1967-68 and 1985-87 ▪ S. G. Simpson and D. Limmer

BOBCAT HABITAT USE IN SOUTHEASTERN MONTANA DURING PERIODS OF HIGH AND LOW LAGOMORPH ABUNDANCE ▪ B. J. Giddings, G. L. Risdahl, and L. R. Irby …

Groundwater Levels In Nebraska, 1989, Michael J. Ellis, Gregory V. Steele, Perry B. Wigley

Conservation and Survey Division

No abstract provided.

United States Patent: Metaginsulator Composites Having Improved Properties And Method For Their Preparation, Chia-Ling Chien, Gang Xiao, Sy-Hwang Liou

Sy-Hwang Liou Publications

Improved cermets having superior properties comprising a ferromagnetic metal and an insulator. By controlling process conditions, cermets having high magnetization and high coercivity as well as chemical stability, wear resistance and corrosion resistance are prepared. The cermets of this invention find particular utility as high density recording media.

Effects Of Magnetic Field And Temperature On The Critical Current Hysteresis In Tl-Ca-Ba-Cu-O Thin Films, Hung-Lun Chang, Jenh-Yih Juang, Sy_Hwang Liou, Tzeng-Ming Uen, Yih-Shun Gou

Sy-Hwang Liou Publications

The behavior of the critical current density of Tl-Ca-Ba-Cu-O superconducting thin films in a cycling magnetic field was investigated. The hysteresis of the transport J_c manifested similar features to those found in polycrystalline Y-Ba-Cu-O and granular Nb, Al thin films in zero-field cooling. However, a novel result of the transport J_c in field-cooled samples has been observed. The results were attributed to the presence of a saturated trapped magnetic flux in the weaklink network. The effects of temperature on both the trapped flux and the transport J_c suggest the existence of various states of the trapped flux …

Kinetic-Energy Density Functional For A Special Shape-Invariant Potential Of A One-Dimensional Two-Level System , Jiushu Shao, John J. Stezowski

John J. Stezowski Publications

By introducing the concept of supersymmetry to quantum mechanics, several authors have shown that exactly soluble potentials, including all those well known, are easily constructed. Is the kinetic-energy density functional corresponding to these potentials a simple form? We show that the answer is no, even to the simplest one, the harmonic potential, if one builds the kinetic-energy density functional from the reduced density matrix.

The Pacific/ North American Teleconnection Pattern And United States Climate. Part I: Regional Temperature And Precipitation Associations, Daniel J. Leathers, Brent Yarnal, Michael A. Palecki

School of Natural Resources: Faculty Publications

The Pacific/ North American (PNA) teleconnection index, a measure of the strength and phase of the PNA teleconnection pattern, is related to the variations of the surface climate of the United States from 1947 through 1982 for the autumn, winter, and spring months when the PNA is a main mode of Northern Hemisphere mid-tropospheric variability. The results demonstrate that the PNA index is highly correlated with both regional temperature and precipitation. The strongest, most extensive correlations between the index and temperature are observed in winter, but large areas of the country show important associations during the spring and autumn as …

The Probe, Issue 105 - November 1990

The Probe: Newsletter of the National Animal Damage Control Association

THE PROBE
National Animal Damage Control Association
NOVEMBER 1990
What's Happening at the Denver Wildlife Research Center?
Relocation of Golden Eagles
Goose Repellents
North Dakota Habitat Management
Breakaway Snare Development
Impact of Cormorants on the Catfish Industry
Strychnine Registrations
Prevention and Control Tips
Bird Dispersal Techniques
Pesticide Updates
Wildlife Damage in the News
Gulls Damage Silage Bags in New York
Coyote Snaring Program Stopped at Airport
Prairie Dogs Evicted From National Guard Base
Deer Herd Struck by Business Jet
Groundhogs Blackout Airport Lights
WLFA Intervenes in California Bear Suit
NADCA Volunteers

Predictions Of Cell Damage Rates For Lifesat Missions, Francis A. Cucinotta, William Atwell, Alva C. Hardy, Michael J. Golightly, John W. Wilson, Lawrence W. Townsend, Judy Shinn, John E. Nealy, Robert Katz

Robert Katz Publications

Radiological experiments with cell cultures are expected to be performed on Lifesat to study possible gravitational dependence on cellular response. Predictions of cell damage rates for well-studied systems are expected to help guide in the selection of orbits and the design of experiments. In this report we estimate the fractions of cell death and neoplastic transformation of C3H10T1/2 cells (cultured mouse cells) for the proposed Lifesat orbits. The parametric cellular track model of Katz et al. (refs. 1 and 2) is employed using cellular response parameters derived from the experiments of Yang et al. (refs. 3 and 4). The contributions …

Some "Do's" And "Don't'S" For Using Computers In Science Instruction, Glenn A. Sowell, Robert Fuller

Robert G. Fuller Publications

As science researchers and professors, we have had a fairly broad collection of experiences in using computers, from batch-processing and number crunching in large computer systems using FORTRAN and symbolic languages to teaching problem-solving courses for nonscience students using personal computers. While we claim no special computer expertise, we both own computers and are frequently called upon to offer advice to our colleagues who are greater novices than we are. Hence, on the basis of reflections on our experiences and observations of what we have seen other people and institutions do, we have compiled a list of “Do’s” and “Don’ts” …

Ab Initio Studies Of The Phase Transitions In K2Seo4, H. M. Lu, John R. Hardy

John R. Hardy Papers

An ab initio model is developed for the potentials in ionic molecular solids in which the electron covalency within the molecular ions substantially affects the interionic interactions. By treating the intermolecular and intramolecular interactions on the basis of the true electron charge densities of the molecular ions, this new model leads to an accurate parameter-free description of the potentialenergy surfaces for such crystals. We performed first-principles static structural relaxation, supercell molecular-dynamics simulation, and lattice-dynamics studies for the room-temperature paraelectric phase and the lower-temperature ferroelectric superstructure of K₂SeO₄ and predicted with good accuracy the transition from the former …

Synchrotron Radiation Induced Chemical Vapor Deposition Of Thin Films From Metal Hexacarbonyls*, Derrick C. Mancini, Shikha Varma, John K. Simons, Richard A. Rosenberg, Peter A. Dowben

Peter Dowben Publications

We have studied the initial stages of synchrotron radiation [SR] induced chemical vapor deposition [CVD] of metal-containing thin films from metal hexacarbonyl gases. We have measured the dependence of the initial deposition rate upon gas pressure at room temperature. Substrates were exposed to SR for single fills of the electron storage ring at constant pressure of Mo(CO)₆, Cr(CO)₆, or W(CO) ₆ gas. Deposition was monitored in situ by Auger electron spectroscopy using the SW as the excitation source. The presence of metal, carbon, and oxygen in the deposited films was observed, and the results are consistent …

Laser-Induced Detachment Processes In An Electric Field, Bo Gao, Anthony F. Starace

Anthony F. Starace Publications

An analytic momentum-space wave function for an electron in both laser and static uniform electric fields is presented. It is used to obtain analytic multiphoton detachment cross sections in a static, uniform electric field which include effects of static-field-induced electron-photon interactions. These general results are not restricted to weak laser intensities or to weak static-field strengths and depend only on (a) the electric dipole approximation and (b) the approximation that final-state electron-atom interactions are ignored. Four specific predictions of our general formulas for the most interesting case of linearly polarized light polarized along the static-field direction are presented for weakly …

Wildlife Damage News, Volume 1, Fall 1990

Wildlife Damage News

CONTENTS:
Relocating Suburban Raccoons
WDM Advisory Committee Meets
Rabies Publications from NYS-DOH
Deer Damage Management Demonstration
Current Literature
DMU Citizen Task Force Meetings
WDM Inservice Education
Deer Management in Christmas Tree Plantations
Nuisance Wildlife/Wildlife Rehabilitator Information
Hunters—Protection from Lyme Disease

Oil And Gas Developments In North Mid-Continent In 1989., Shirley E. Paul, Bruce W. Netzler, Raymond R. Burchett, Paul H. Roberts, Robert Peters, Donivan L. Gordon, John H. Mossler

Conservation and Survey Division

No abstract provided.

Deposition Of Boron-Containing Films From Decaborane, James T. Spencer, Peter A. Dowben, Yoon G. Kim

Peter Dowben Publications

Depopsition of a boron nitride film is carried out by introducing decaborane and dry nitrogen or ammonia into a plasma-assisted chemical vapor deposition chamber. The nitrogen or ammonia partial pressure should provide an excess over the decarborane pressures for example 200 milliTorr of N₂ or NH₃ and 50 MilliTorr of B₁₀H₁₄. Other film layers can also be produced starting from decaborane.

The Long-Period Field Rr Lyrae Stars, Edward G. Schmidt, Charles G. Loomis, Andrew T. Groebner, Chris T. Potter

Edward Schmidt Publications

VR light curve3 have been obtained for 16 faint variable stars with periods shorter than 1 day. Although, as expected, most of the light curves are typical of Bailey-type ab RR Lyrae stars, some have slower rises to maximum and flatter tops. Fourier decomposition was performed to further explore these trends. Combining these data with previously published Fourier decompositions of RR Lyrae light curves, we find that the Fourier coefficients are essentially constant for periods shorter than three-quarters of a day for Bailey-type ab RR Lyrae stars but that the amplitude ratios, R (12), R (13), and R (14), decrease …

Recent Secular Variations In The Extent Of Northern Hemisphere Snow Cover, David A. Robinson, Kenneth F. Dewey

Department of Earth and Atmospheric Sciences: Faculty Publications

Northern hemisphere snow cover during 1988 and 1989 was at its lowest extent since the advent of reliable satellite snow-cover monitoring 1972; running some 8-10% below the eighteen-year annual mean of 25.7 million km² . Monthly minima for the period of record occurred six times during these two years. In general, the last nine years of the satellite record had less extensive cover than the 1972-80 interval. Negative anomalies during the 1980s were largest over Eurasia in all seasons, and in the Spring over North America. Hemispheric seasonal means for the most recent nine years were 3.7% to 8.4% …

The Prairie Naturalist Volume 22, No. 3. September 1990

The Prairie Naturalist

Paul B. Kannowski, Editor

Nikki R. Seabloom, Assistant Editor

Douglas H. Johnson, Book Review Editor

CONTENTS

ASSEMBLAGES OF SMALL FISH IN THREE HABITAT TYPES ALONG THE PLATTE RIVER, NEBRASKA ▪ D. T. O'Shea, W. A. Hubert, and S. H. Anderson

SPAWNING HABITAT OF CHANNEL CATFISH IN THE POWDER RIVER SYSTEM, WYOMING-MONTANA D. R. Gerhardt and W. A. Hubert

OCCURRENCE OF AMERICAN WHITE PELICANS ALONG THE PLATTE RIVER, NEBRASKA ▪ J. G. Sidle, C. A. Faanes, and W. G. Jobman

DIET OF CANVASBACKS DURING BREEDING ▪ J. E. Austin, J. R. Serie, and J. H. Noyes

BROOD HABITAT USE OF RIO …

Water Current, Volume 22, September 1990

Water Current Newsletter

NATO Workshop Explores World-Wide Nitrate Problems
From the Director: Priorities Set for Future Research
Water Conservation Theme of Tour to Texas
Ag Production Could Be Revolutionized with System
Environmental Education Directory Now Available
NWCC Holds Fall Annual Meeting
Pesticide Regulation Issues Facing Nebraska
Two Conferences Set for Groundwater Enthusiasts

Radiosensitivity Parameters For Cell Survival In Tradescantia And For Chromosome Aberrations In Chinese Hamster Cells, Robert Katz, G. Huang

Robert Katz Publications

Data for the loss of reproductive integrity of Tradescantia stamen hairs irradiated with 250 keV X rays and 0.43 and 5.6 MeV neutrons are fitted with radiosensitivity parameters from track theory, with E₀ and m from X-ray data while σ₀ and κ are then found from neutron irradiations. The X-ray data display a clear shoulder with 100% survival below 0.18 Gy and a “linear tail.” Data for abnormal metaphases and chromatid exchanges in Chinese Hamster cells have also been fitted with parameters. Parameters for abnormal metaphases are nearly identical with those obtained years ago for cell killing from …

The Probe, Issue 104 - September/October 1990

The Probe: Newsletter of the National Animal Damage Control Association

THE PROBE National Animal Damage Control Association
SEPTEMBER/OCTOBER 1990
Pride and Professionalism In ADC
Hawthorne Wraps Up ADC Four Corners Rendezvous
Prevention and Control Tips
White-footed and Deer Mice
Pesticide Updates
Wildlife Damage in the News
Animal Damage Control

Doubly Differential Detachment Cross Sections For Fast H-–Rare-Gas Collisions, Chih-Ray Liu, Anthony F. Starace

Anthony F. Starace Publications

Detailed theoretical analyses are presented of the projectile-energy dependence as well as the target dependence of the electron-detachment collision processes, H^-+T→H(n=2)+T*+e^-. These analyses are illustrated by calculations of both projectile-frame and laboratory-frame doubly differential cross sections (DDCS’s) for 0.5-, 1.0-, and 1.5-MeV H^- collisions with He targets and for 0.5-MeV H^- collisions with Ne, Ar, Kr, and Xe targets; in addition, we present laboratory frame DDCS’s for 0.1-MeV H^- collisions with Xe targets. Comparisons with available experimental data are given.

Two New Short-Period Cepheids, Edward G. Schmidt, Bradley A. Gross

Edward Schmidt Publications

The General Catalogue of Variable Stars gives periods of slightly less than three-quarters of a day for the stars NO Cas and CN Tau. However, new photometry demonstrates that their periods are actually 2.6 and 1.8 days, respectively, and they are thus classical Cepheids. Fourier decompositions of their light curves are performed, and they are found to be members of a class of Cepheids with periods less than three days which may be related to the s-Cepheids. These two stars represent the shortest and longest known members of this class and thus are very useful in defining its properties in …