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Articles 20971 - 21000 of 21971

Full-Text Articles in Physical Sciences and Mathematics

Magnetic And Crystallographic Order In Α‐Manganese, A. C. Lawson, Allen C. Larson, M. C. Aronson, S. Johnson, Z. Fisk, Paul C. Canfield, J. D. Thompson, R. B. Von Dreele Jan 1994

Magnetic And Crystallographic Order In Α‐Manganese, A. C. Lawson, Allen C. Larson, M. C. Aronson, S. Johnson, Z. Fisk, Paul C. Canfield, J. D. Thompson, R. B. Von Dreele

Paul C. Canfield

We have made time‐of‐flight neutron diffractionmeasurements on α‐manganese metal. Powder diffraction measurements were made at 14 temperatures between 15 and 305 K, and single crystalmeasurements were made at 15 and 300 K. We found that the crystal structure of α‐Mn is tetragonal below its Néel point of 100 K, with crystal symmetryI4̄2m and magnetic (Shubnikov) symmetry P I 4̄21 c. In agreement with the earlier results of Yamada et al., there are six independent magnetic atoms, and we found that their moments are weakly temperature dependent. The onset of magnetic order causes slight changes in the atomic positions and in …


A Computer-Based Atlas Of Global Instrumental Climate Data, Raymond S. Bradley, Linda G. Ahem, Frank T. Keimig Jan 1994

A Computer-Based Atlas Of Global Instrumental Climate Data, Raymond S. Bradley, Linda G. Ahem, Frank T. Keimig

Raymond S Bradley

Color-shaded and contoured images of global gridded instrumental data have been produced as a computer-based atlas, available to the climate community through Internet. Each image simultaneously depicts anomaly maps of surface temperature, sea level pressure, 500- mb geopotential heights, and percentages of reference period precipitation. Monthly, seasonal, and annual composites are available, in either cylindrical equidistant or Northern and Southern Hemisphere polar projections. Temperature maps are available from 1854 to 1991, precipitation maps from 1851 to 1989, sea level pressure maps from 1899 to 1991, and 500-mb height maps from 1946 to 1991. All images exist as GIP (Graphics Interchange …


Field Identification Of Birdseye In Sugar Maple (Acer Saccharum Marsh.), Douglas D. Stokke, Don C. Bragg Jan 1994

Field Identification Of Birdseye In Sugar Maple (Acer Saccharum Marsh.), Douglas D. Stokke, Don C. Bragg

Douglas D. Stokke

Birdseye grain distortions in sugar maple must be identified to capture the full value of a timber sale throughout the economic range of birdseye's occurrence. Even when relatively common, birdseye veneer typically makes up less than 1 percent of the harvested volume, but may account for one-half of the value of the sale. With prices recently reaching $50,000 per Mbf for prime logs, omission of birdseye (when present) from cruise data could cause significant economic loss for the forest landowner. But figured wood can sometimes be detected in standing timber (Pillow 1955). Field identification of birdseye sugar maple is critical …


Detection Of Oh+ In Its A 1-Delta State By Far Infrared Laser Magnetic Resonance, Thomas Varberg, K. M. Evenson, J. M. Brown Jan 1994

Detection Of Oh+ In Its A 1-Delta State By Far Infrared Laser Magnetic Resonance, Thomas Varberg, K. M. Evenson, J. M. Brown

Thomas D. Varberg

No abstract provided.


Pre-1994 Journal Articles, David Bressoud Jan 1994

Pre-1994 Journal Articles, David Bressoud

David Bressoud

No abstract provided.


Direct Simulation Monte Carlo For Thin Film Bearings, Alejandro Garcia, B. Alder, F. J. Alexander Jan 1994

Direct Simulation Monte Carlo For Thin Film Bearings, Alejandro Garcia, B. Alder, F. J. Alexander

Alejandro Garcia

The direct simulation Monte Carlo (DSMC) scheme is used to study the gas flow under a read/write head positioned nanometers above a moving disk drive platter (the slider bearing problem). In most cases, impressive agreement is found between the particle-based simulation and numerical solutions of the continuum hydrodynamic Reynolds equation which has been corrected for slip. However, at very high platter speeds the gas is far from equilibrium, and the load capacity for the slider bearing cannot be accurately computed from the hydrodynamic pressure.


Microscopic Simulation Of Dilute Gases With Adjustable Transport Coefficients, Alejandro Garcia, F. Baras, M. Malek Mansour Jan 1994

Microscopic Simulation Of Dilute Gases With Adjustable Transport Coefficients, Alejandro Garcia, F. Baras, M. Malek Mansour

Alejandro Garcia

The Bird algorithm is a computationally efficient method for simulating dilute gas flows. However, due to the relatively large transport coefficients at low densities, high Rayleigh or Reynolds numbers are difficult to achieve by this technique. We present a modified version of the Bird algorithm in which the relaxation processes are enhanced and the transport coefficients reduced, while preserving the correct equilibrium and nonequilibrium fluid properties. The present algorithm is found to be two to three orders of magnitude faster than molecular dynamics for simulating complex hydrodynamical flows.


Dynamic Phenomena In Superconducting Oxides By Esr, Juana Vivó Acrivos, Lei Chen, C. M. Burch, P. Metcalf, J. M. Honig, R. S. Liu, K. K. Singh Jan 1994

Dynamic Phenomena In Superconducting Oxides By Esr, Juana Vivó Acrivos, Lei Chen, C. M. Burch, P. Metcalf, J. M. Honig, R. S. Liu, K. K. Singh

Juana Vivó Acrivos

Dynamic electron spin resonance (ESR) measurements compare the paramagnetic and antiferromagnetic (AF) properties of superconducting oxides in the range 4 K to room temperature, at 8 MHz and 9.36 GHz. Two are derivatives of YBa2Cu30 7: 1: Nd(Nd0.05Ba0.95 )2Cu30 7, Te0 =72 K and II: Y0.2Cao.8Sr2[Cu2(Tlo.5Pb0.5 )]07, Te0 =108 K and two are cases where AF ordering dominates the weak superconductivity: III: Nb01.1> 1. 25 ~Teo~ 10 K and IV: La2Ni04.00, 70 K :::: Teo:::: 40 K. At temperatures 298:::: T:::: 64 K, the ESR absorption by I indicates orthorhombic symmetry. The peaks at Ke =2.06, gb =2.13, and Ka …


Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle Jan 1994

Expression Of Prelamin A Confers Sensitivity Of Dna Biosynthesis To Lovastatin On F9 Teratocarcinoma Cells, Michael Sinensky, T. Mclain, K. Fantle

Michael Sinensky

No abstract provided.


The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton Jan 1994

The Processing Pathway Of Prelamin A, Michael Sinensky, K. Fantle, M. Trujillo, T. Mclain, A. Kupfer, M. Dalton

Michael Sinensky

The conversion of mammalian prelamin A to mature lamin A proceeds through the removal of 18 amino acids from the carboxyl terminus. The initial step in this processing is the isoprenylation of a CAAX box cysteine. This proteolytic event is distinctive for prelamin A among the known prenylated mammalian proteins. Since the carboxyl terminus of prelamin A is removed during maturation, it is not obvious that this protein would undergo the two reactions subsequent to prenylation observed in other CAAX box proteins-the endoproteolytic removal of the carboxyl-terminal 3 amino acids and the subsequent methylation of the now carboxyl-terminal cysteine. To …


Efficient Timestamp Input And Output, Curtis Dyreson, Richard T. Snodgrass Jan 1994

Efficient Timestamp Input And Output, Curtis Dyreson, Richard T. Snodgrass

Curtis Dyreson

In this paper we provide efficient algorithms for converting between the internal form of a timestamp, and various external forms, principally character strings specifying Gregorian dates. We give several algorithms that explore a range of time and space tradeoffs. Unlike previous algorithms that explore a range of time and space tradeoffs. Unlike previous algorithms, those discussed here have a constant time cost over a greatly extended range of timestamp values. These algorithms are especially useful in operating systems and in database management systems.


Comparison Between Calculatedand Observed F-Region Density Profiles At Jicamarca, Peru, A. J. Preble, D. N. Anderson, Bela G. Fejer, P. H. Doherty Jan 1994

Comparison Between Calculatedand Observed F-Region Density Profiles At Jicamarca, Peru, A. J. Preble, D. N. Anderson, Bela G. Fejer, P. H. Doherty

Bela G. Fejer

Electron density profiles and isodensity contours derived from Jicamarca incoherent scatter radar observations in Peru for October 1–2, 1970, are compared in detail with results from the Phillips Laboratory global theoretical ionospheric model. This model solves the ion continuity equation for O+ concentration through production, loss, and transport of ionization. The primary factor controlling the peak plasma density at Jicamarca is the vertical E×B drift, which drives the ionization upward during the day and downward at night. When we use the measured drift in the model, we achieve excellent results with the measured electron density profiles. We illustrate the sensitivity …


Nanoscale Patterning And Oxidation Of H-Passivated Si(100)-2x1 Surfaces With An Ultrahigh Vacuum Scanning Tunneling Microscope, J. W. Lyding, T. -C. Shen, J. S. Hubaceck, J. R. Tucker, G. C. Abeln Jan 1994

Nanoscale Patterning And Oxidation Of H-Passivated Si(100)-2x1 Surfaces With An Ultrahigh Vacuum Scanning Tunneling Microscope, J. W. Lyding, T. -C. Shen, J. S. Hubaceck, J. R. Tucker, G. C. Abeln

T. -C. Shen

Nanoscale patterning of the hydrogen terminated Si(100)‐2×1 surface has been achieved with an ultrahigh vacuum scanning tunneling microscope.Patterning occurs when electrons field emitted from the probe locally desorb hydrogen, converting the surface into clean silicon. Linewidths of 1 nm on a 3 nm pitch are achieved by this technique. Local chemistry is also demonstrated by the selective oxidation of the patterned areas. During oxidation, the linewidth is preserved and the surrounding H‐passivated regions remain unaffected, indicating the potential use of this technique in multistep lithography processes.


Proof Without Words: Fair Allocation Of A Pizza, Stan Wagon, L. Carter Dec 1993

Proof Without Words: Fair Allocation Of A Pizza, Stan Wagon, L. Carter

Stan Wagon, Retired

No abstract provided.


Upper Ordovician Graptolites From The North American Midcontinent:University Biostratigraphy, Biofacies, And Sea-Level, Daniel Goldman Dec 1993

Upper Ordovician Graptolites From The North American Midcontinent:University Biostratigraphy, Biofacies, And Sea-Level, Daniel Goldman

Daniel Goldman

Funding agency: The Ohio State University Amount: $23,000.00


The Power Of Visualization: Notes From A Mathematica Course, Stan Wagon Dec 1993

The Power Of Visualization: Notes From A Mathematica Course, Stan Wagon

Stan Wagon, Retired

No abstract provided.


A Mathematical Magic Trick, Stan Wagon Dec 1993

A Mathematical Magic Trick, Stan Wagon

Stan Wagon, Retired

No abstract provided.


Foliations Transverse To Fibers Of Seifert Manifolds, Ramin Naimi Dec 1993

Foliations Transverse To Fibers Of Seifert Manifolds, Ramin Naimi

Ramin Naimi

No abstract provided.


Multithreaded Computer Architecture: A Summary Of The State Of The Art, Robert Iannucci, Guang Gao, Robert Halstead, Burton Smith Dec 1993

Multithreaded Computer Architecture: A Summary Of The State Of The Art, Robert Iannucci, Guang Gao, Robert Halstead, Burton Smith

Robert A Iannucci

No abstract provided.


Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung Dec 1993

Protein S-Thiolation And Dethiolation, James Thomas, Yuh-Cherng Chai, Che-Hun Jung

Yuh-Cherng Chai

No abstract provided.


U/Pb Sphene Date Of Mylonitization Associated With The Proterozoic Laramie Peak Shear Zone, Laramie Mountains, Wy, Phillip Resor, K Chamberlain, A Snoke, C Frost Dec 1993

U/Pb Sphene Date Of Mylonitization Associated With The Proterozoic Laramie Peak Shear Zone, Laramie Mountains, Wy, Phillip Resor, K Chamberlain, A Snoke, C Frost

Phillip G Resor

In this paper, we show that deformation can be dated by combining mesoscopic and microscopic structural observations with an understanding of metamorphic mineral reactions and U-Pb ages of newly grown sphene (titanite). This approach can be used on a variety of rock types that have been deformed at a wide range of metamorphic conditions. In an example from the Proterozoic Laramie Peak shear zone of southeastern Wyoming, a single period of syntectonic sphene growth in sheared mafic dikes is documented both by a strong spatial relationship between deformation and metamorphism and by sphene microtextures. U-Pb analyses of sphene separates give …


Constructing Essential Laminations In 3-Manifolds Obtained By Surgery On 2-Bridge Knots, Ramin Naimi Dec 1993

Constructing Essential Laminations In 3-Manifolds Obtained By Surgery On 2-Bridge Knots, Ramin Naimi

Ramin Naimi

No abstract provided.


Technology Transfer At Motorola, Robert Yacobellis Dec 1993

Technology Transfer At Motorola, Robert Yacobellis

Robert H Yacobellis

No abstract provided.


Thermodynamics Of A Free Q Fermion Gas, Asim Gangopadhyaya Dec 1993

Thermodynamics Of A Free Q Fermion Gas, Asim Gangopadhyaya

Asim Gangopadhyaya

We study the thermodynamics of a q-fermion gas for complex values of q on the unit circle. Special emphasis is given to the study of the virial coefficients and the specific heat of this gas. In particular, it is shown that if any state can accommodate up to p q-fermions, then the first p virial coefficients of such a gas are the same as that of a gas of free bosons. Explicit expressions for the deviation of higher virial coefficients from the corresponding values for a Bose gas are obtained. Further, as for ordinary fermions, it is shown that the …


Clam Demography, Stan Wagon Dec 1993

Clam Demography, Stan Wagon

Stan Wagon, Retired

No abstract provided.


Symmetrical Porosity Of Symmetrical Cantor Sets, M. Evans, P. Humke, Karen Saxe Dec 1993

Symmetrical Porosity Of Symmetrical Cantor Sets, M. Evans, P. Humke, Karen Saxe

Karen Saxe

No abstract provided.


Hexagons And Squares In A Passive Nonlinear Optical System, John Geddes, R.A. Indik, J.V. Moloney, Willie Firth Dec 1993

Hexagons And Squares In A Passive Nonlinear Optical System, John Geddes, R.A. Indik, J.V. Moloney, Willie Firth

John B. Geddes

Pattern formation is analyzed and simulated in a nonlinear optical system involving all three space dimensions as well as time in an essential way. This system, counterpropagation in a Kerr medium, is shown to lose stability, for sufficient pump intensity, to a nonuniform spatial pattern. We observe hexagonal patterns in a self-focusing medium, and squares in a self-defocusing one, in good agreement with analysis based on symmetry and asymptotic expansions.


An Investigation Of The Stability Of Carbonate Minerals, Andrea Koziol Dec 1993

An Investigation Of The Stability Of Carbonate Minerals, Andrea Koziol

Andrea M. Koziol

This research project received funding from the University of Dayton Research Council from January 1994 to September 1994.


A Note On The Real Symmetric Eigenvalue, William F. Trench Dec 1993

A Note On The Real Symmetric Eigenvalue, William F. Trench

William F. Trench

No abstract provided.


A Bayesian Approach To Additive Nonparametric Regression, Michael S. Smith, Robert Kohn Dec 1993

A Bayesian Approach To Additive Nonparametric Regression, Michael S. Smith, Robert Kohn

Michael Stanley Smith

This proceedings paper was the first to suggest using a Gaussian g-prior combined with a point mass to undertake Bayesian variable selection in a Gaussian linear regression model. It also was the first to suggest integrating out the regression parameters and variance in closed form, resulting in an efficient Gibbs sampling scheme. The idea was applied to estimate regression functions in an additive model by using a linear basis expansion for each component function in an additive model. The conference proceeding was eventually published in a slightly tighter form in Journal of Econometrics (1996).