Physical Sciences and Mathematics Commons^™

Third Sound And The Decay Of Persistent Currents In Unsaturated 3he-4he Films, Robert Hallock

Robert Hallock

We report the observation of metastable currents in unsaturated 3He-4He-mixture films. The decay rate of these currents is found to be an increasing function of 3He concentration in the film. A simple model for the role of the 3He, adequate to explain our observations of the concentration dependence of the third-sound velocity, does not agree with the measured decay rates.

Very-Long-Lived Metastable Vibrational States Of Ba2++ , Stanley J. Sramek, J.A. Macek, Gordon A. Gallup

Gordon Gallup Publications

Potential-energy curves for the ¹ Σ^g+ states of Ba₂⁺⁺ are exhibited. The ground-state curve shows a local minimum lying 0.0562 a.u. above the energy at infinite separation, and a local maximum lying at 0.0618. These features form a potential well in which metastable vibrational states can exist. The lifetimes are estimated as high as 10¹⁹⁷ sec, using the WKB method. Considerations regarding experimental formation and detection of bound Ba₂⁺⁺ are discussed.

Electron Irradiation Defects In N-Type Gaas, J. W. Farmer, David C. Look

Physics Faculty Publications

We have studied the production and annealing of defects produced by 1-MeV electron irradiation of n-type GaAs. Two of these defects lie at 0.15 and 0.31 eV from the conduction band, respectively; in addition, there is at least one acceptor much closer to the valence band. The carrier-removal rate depends upon sample purity but is independent of the irradiation flux. The removal rate is also highly dependent upon the position of the the Fermi level, an effect which is considered in some detail. At about 200°C, the defects recover in two stages, with the respective recovery rates given by λ …

Studies Of The Reorientational Relaxation Of Pyridine In Water By Depolarized Rayleigh Light Scattering, C. H. Wang, Scott L. Whittenburg, P. A. Lund, D. H. Christensen

Chemistry and Biochemistry Faculty Publications

The depolarized Rayleigh spectra of aqueous solutions of pyridine have been studied using a high‐finesse Fabry–Perot interferometer as a function of temperature and concentration. The Rayleigh relaxation times are found to have a complex concentration and viscosity dependence. The classical Stokes–Einstein–Debye equation for molecular reorientation breaks down in this system. The Rayleigh relaxation time of pyridine molecules is not determined by the macroscopic shear viscosity of the solution. The specific interaction due to the formation of hydrogen bonds between pyridine and water molecules plays a very important role in affecting the relaxation time. At a fixed temperature the plot of …

Partial Chemical Equilibrium In Fluid Dynamics, John D. Ramshaw

Physics Faculty Publications and Presentations

An analysis is given for the flow of a multicomponent fluid in which an arbitrary number of chemical reactions may occur, some of which are in equilibrium while the others proceed kinetically. The primitive equations describing this situation are inconvenient to use because the progress rates ω [subscript s] for the equilibrium reactions are determined implicitly by the associated equilibrium constraint conditions. Two alternative equivalent equation systems that are more pleasant to deal with are derived. In the first system, the ω [subscript s] are eliminated by replacing the transport equations for the chemical species involved in the equilibrium reactions …

Angular Differential Cross Sections For Excitation Of Atomic Hydrogen To The N=2 Level By Proton Impact, John T. Park, Judith E. Aldag, Jerry Peacher, Jacob M. George

Physics Faculty Research & Creative Works

Differential cross sections for 15-145-keV proton impact excitation of atomic hydrogen to the n=2 level have been determined for center-of-mass scattering angles 0 to 1.2 mrad. The cross sections were obtained from an analysis of the angular distribution of protons which had lost an energy corresponding to the excitation of atomic hydrogen to its n=2 level. The differential cross sections obtained are in rather good agreement with available coupled-state calculations as well as the simpler Glauber-approximation calculations. However, at the larger scattering angles the cross sections obtained from the theoretical treatments appear to decrease more rapidly than the experimental data.

Potential Use Of Chemical Spot Test Method For Submicron Aerosol Sizing, Paul C. Yue, Josef Podzimek

Physics Faculty Research & Creative Works

A submicron particle, which is too small to be observed in an optical microscope, may form an observable spot on a chemically prepared substrate of the collector. The size of the spot or "Liesegang circle" is related to the aerodynamic diameter of the particle through a magnification factor. This paper presents the experimental results of the study of this factor using sodium chloride aerosol in the size range of 0.5 to 2 pm which has not previously been studied. We calibrated a cylindrical centrifuge with known sized latex particles. A relationship between the aerodynamic diameter and the deposition length is …

Photoionization Of The 5S Subshell Of Xenon: A Multichannel K-Matrix Calculation Including Spin-Orbit Interactions, Keh-Ning Huang, Anthony F. Starace

Anthony F. Starace Publications

Ab initio theoretical calculations are presented for the cross section, angular distribution, and spin polarization of photoelectrons for the 5s subshell of xenon. Starting from an initial basis of nonrelativistic Hartree-Fock wave functions, the authors treat the effect of final-state spin-orbit interaction in the Breit-Pauli approximation exactly. Electrostatic correlations between the 5s and 5p subshells are also included. Good agreement is obtained with experiment in the case of the photoionization cross section, but only qualitative agreement with experiment and with other theoretical calculations is obtained in the case of the photoelectron angular distribution due to the difficulty …

Four-Color And Hβ Photometry Of Stars In The Galactic Cluster Ngc 6087, Edward G. Schmidt

Edward Schmidt Publications

Four-color and Hβ photometry has been obtained for 16 stars in the open cluster NGC 6087. Based on this photometry the membership of these stars in the cluster is discussed. Using stars which appear to be members a color excess of E(b – y) = 0^m.23 and a distance modulus of (V₀ – M_v) = 9^m.60 are derived. This distance modulus is about 0^m.4 less than previous values and indicates a lower luminosity for the Cepheid member, S Nor, than is currently accepted.

Navigational Compass In Magnetic Bacteria, Richard B. Frankel, R. P. Blakemore

Physics

Magnetotactic bacteria that orient and swim in a preferred direction in the geomagnetic field contain sufficient single domain magnetite to constitute a biomagnetic compass.

Magnetic Properties Of [Fe4S4(Sr)4]3- Clusters, G. C. Papaefthymiou, Richard B. Frankel, S. Foner, E. J. Laskowski, R. H. Holm

Physics

No abstract provided.

Electronic Properties Of Molybdenum-Iron-Sulfur-Clusters: Approaches To The Molybdenum Site In Nitrogenase, Richard B. Frankel, T. E. Wolff, P. P. Power, R. H. Holm

Physics

No abstract provided.

The Effects On Grain-Boundary Processes Of The Steps In The Boundary Plane Associated With The Cores Of Grain-Boundary Dislocations, Alexander H. King, D. A. Smith

Alexander H. King

The contribution of the associated steps to the properties of grain-boundary dislocations are investigated. Two methods of step-height determination are given and it is shown that the step height, like the Burgers vector, must be conserved during the reactions of grain-boundary dislocations: this is not always automatic and additional coherent steps must take part in some reactions. The energies associated with steps have been estimated and compared with the elastic energies of grain-boundary dislocations; these comparisons suggest that (a) the reduction of elastic energy alone may not be a sufficient criterion for the progress of a reaction and (b) that …

Thermodynamic Model And Sum Rules For Three-Phase Coexistence Near Thetricritical Point In A Liquid Mixture, Miron Kaufman, K. K. Bardhan, Robert B. Griffiths

Miron Kaufman

Two sum rules for order-parameter susceptibilities are derived for the classical theory of the three-phase region near a tricritical point in ordinary liquid mixtures. The classical theory can also be fitted in a quantitative way to the composition data of Lang and Widom near the tricritical point in the mixture ethanol+ benzene+ water + ammonium sulfate.

Untitled (Subject: Energy), Richard C. Heyser

Unpublished Writings

Fundamental energy relations are explored as a basis for the measurement of physical systems. By considering finite dimensional observations in linear Hilbert space it is shown that a necessary and sufficient condition for the conservation of energy is the partitioning of any observation of that energy into two components which will be related through the Hilbert transform. The consequence of this relationship is demonstrated for the equilibrium storage of energy, point-wave duality in measurements, significance of complex representations involving circular form, the meaning of minimum phase and all-pass properties, and the introduction of new measurement characterizations such as the energy-time …

The Two Parts Of Energy, Richard C. Heyser

Unpublished Writings

In this paper, Richard C. Heyser explains the theories behind measuring sound by discussing its energy. Using what he calls abstract geometry, Heyser argues that measuring the transfer properties (that is, pressure and velocity) of sound's energy aids in the discovery of its amplitude and phase (or in-phase and quadrature).

Continental Drift, Tectonics, And Joshua, Joel W. Block

Physics Faculty Publications

The Bible has served as a source of spiritual inspiration for many centuries. It has been used as a text in the academic disciplines of history, geography, archeology, literature, law, language, and health, as well as in theology. Yet this multipurpose manuscript has been virtually ignored as an earth science reference It is this writer's intent to demonstrate the Bible's value as a geological resource.

Characterization Of Phase Transitions In Vanadium Deuterides, R. L. Tober, Gust Bambakidis

Physics Faculty Publications

No abstract provided.

More On Calculators In Beginning Physics Courses, Harry A. Brown

Physics Faculty Research & Creative Works

No abstract provided.

Injection-Locked Dye Laser Pumped By A Xenon-Lon Laser, E. R. Carney, D. W. Fahey, Laird D. Schearer

Physics Faculty Research & Creative Works

Injection locking of a dye laser is reported for a 4-minor ring-cavity dye User pumped by a xenon-ion laser. Both a He-Ne laser and tunable CW dye laser were used as the injection sources. Copyright © 1980 by The Institute of Electrical and Electronics Engineers, Inc.

Large-Angle Electron-Photon Coincidence Experiment In Atomic Hydrogen, E. Weigold, L. Frost, K. (Kaare) J. Nygaard

Physics Faculty Research & Creative Works

1s-2p excitation in hydrogen has been studied by observing the angular correlation of Lyman photons detected in coincidence with inelastically scattered electrons at 54.4 eV incident energy. The electron scattering angles ranged from 10°to 133°; the results at scattering angles larger than 20°cannot be explained by currently available theories. © 1980 The American Physical Society.

Nonequilibrium Thermodynamics Of Fuel Cells: Heat Release Mechanisms And Voltage, Gerald Wilemski

Physics Faculty Research & Creative Works

Nonequilibrium thermodynamics is used to analyze the spatial distribution of heat release mechanisms occurring in fuel cells operating under load in nonisothermal steady states. Novel contributions to heat release in the bulk electrolyte are found which are analogous to Peltier and Thomson effects in metallic conductors. Expresions for the heat release at individual electrodes are presented. An equation for the voltage of these cells is also derived. © 1980 American Institute of Physics.

Theoretical Lattice-Dynamical Studies Of The Incommensurate Phase Transformation In K2Seo4, M. S. Haque, John R. Hardy

John R. Hardy Papers

We have made detailed lattice-dynamical studies of the origin of the incommensurate phase transition in potassium selenate. These were based on a rigid-ion model with Coulomb interactions, and also short-range interactions between restricted numbers of close neighbors. The associated short-range force constants were determined using the static equilibrium conditions for the crystal and the observed Raman frequencies. The calculations were made for the room temperature structure using the quasiharmonic approximation in which the effects of varying temperature were simulated by varying the short-range force constants. In this way we were able to show that the crystal has a low-frequency optic …

Four-Color And Hβ Photometry Of Stars In The Galactic Cluster Ngc 129, Edward G. Schmidt

Edward Schmidt Publications

Four-color and photometry has been obtained for 22 stars in the field of the open cluster NGC 129. Based on this photometry, the membership of these stars in the cluster is discussed and it is found that many are field stars. The color excesses for cluster members obtained here range from E(b – y) = 0.207 to 0.513 and are larger than those found from previous UBV photometry. It has been suggested that this cluster contains a nonvariable Cepheid strip star. However, the present reddening places this star at the edge of the instability strip. A true …

Angular And Energy Distribution Of Electrons From 15- To 150-Kev H0+He Collisions, M. Eugene Rudd, J. S. Risley, J. Fryar, R. G. Rolfes

M. Eugene Rudd Publications

An electrostatic analyzer positioned at various angles has been used to measure absolute values of cross sections for electron production in collisions of neutral hydrogen atoms with helium as a function of the angle and energy of the ejected electrons. These cross sections are compared with corresponding ones for proton and electron impact to infer the mechanisms of electron production. A prominent peak in the energy distribution due to electron loss from the projectile occurs at an electron velocity equal to that of the projectile. At very low electron energies the similarity of the energy distribution to that due to …

The Cepheid Luminosity Scale, Edward G. Schmidt

Edward Schmidt Publications

The distance moduli of galactic clusters containing classical Cepheids are being redetermined using the four-color and Hβ photometric system. The results for four clusters are presented here and it is found that the distance moduli are smaller than previous values. Possible reasons for this discrepancy are discussed.

Hall-Coefficient And Resistivity At High Pressure In 1t-Tas2, Paul D. Hambourger, F. J. Disalvo

Physics Faculty Publications

No abstract provided.

Determiningeons : A Computer Program For Approximating Lie Generators Admitted By Dynamical Systems, Gregory G. Nagao

University of the Pacific Theses and Dissertations

As was recognized by same of the most reputable physicists of the world such as Galilee and Einstein, the basic laws of physics must inevitably be founded upon invariance principles. Galilean and special relativity stand as historical landmarks that emphasize this message. It's no wonder that the great developments of modern physics (such as those in elementary particle physics) have been keyed upon this concept.

The modern formulation of classical mechanics (see Abraham and Marsden [1]) is based upon "qualitative" or geometric analysis. This is primarily due to the works of Poincare. Poincare showed the value of such geometric analysis …

High-Latitude Convection: Comparison Of A Simple Model With Incoherent Scatter Observations, Jan Josef Sojka, J. C. Foster, W. J. Raitt, Robert W. Schunk, J. R. Doupnik

All Physics Faculty Publications

We have compared a simple model of plasma convection at high latitudes with data obtained from simultaneous measurements made by the incoherent scatter facilities at Chatanika, Alaska and Millstone Hill, Massachusetts in June 1978 during moderately disturbed conditions. The measured horizontal plasma drift velocities were averaged for four days to emphasize gross features of the convection pattern and reduce the effects of substorms. The convection model includes the offset of 11.5° between the geographic and geomagnetic poles, the tendency of plasma to corotate about the geographic pole, and a constant dawn/dusk magnetospheric electric field mapped to a circle about a …

A Comparison Of Model Predictions For Plasma Convection In The Northern And Southern Polar Regions, Jan Josef Sojka, W. J. Raitt, Robert W. Schunk

All Physics Faculty Publications

We have presented model calculations to show how the plasma flow distributions in the northern and southern polar regions differ when viewed from a geographic inertial frame. This reference frame was selected because it is the natural frame for geophysical plasma flow measurements, there being well-known velocity corrections for either satellite or ground-based observations. Although the magnetic invariant latitude, magnetic local time reference frame is better suited to studying magnetospheric processes, a transformation from the geographic inertial frame to this magnetic frame requires both a spatial and velocity transformation, and since the latter correction has generally been neglected, we prefer …