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Articles 35941 - 35970 of 36517

Full-Text Articles in Physical Sciences and Mathematics

A Method For Measuring Magnetization To High Pressures, C. R. Johansen, Mark H. Nelson, J. H. Gardner Mar 1968

A Method For Measuring Magnetization To High Pressures, C. R. Johansen, Mark H. Nelson, J. H. Gardner

Faculty Publications

A partially successful attempt has been made to measure the magnetic moment per unit volume of ferromagnetic materials as a function of pressure to the 100-kbar region. The apparatus, an early version of which has been described previously, consists basically of two opposed Bridgman flat anvils of alumina. One anvil also acts as a dielectric-filled microwave resonant cavity for an x-band spectrometer, allowing electron spin resonance studies to be made to high pressure. The sample to be studied is placed in contact with the anvil-cavity and covered with a pressure-transmitting medium which in turn is encircled by a flat pyrophyllite …

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Projected Hartree Product Wavefunctions, Gordon A. Gallup Feb 1968

Projected Hartree Product Wavefunctions, Gordon A. Gallup

Gordon Gallup Publications

A method for performing a restricted configuration interaction calculation on atoms or molecules based on the use of Young operators from the symmetric groups is discussed and its relation to some other types of calculations is pointed out. The method in its most general form can be said to be an extension of the independent particle approach which represents the wavefunction in terms of the n best possible one-particle orbitals for the n-particle system. Illustrations are given for the hydrogen molecule, the helium atom, and the allyl radical. ©1968 American Institute of Physics

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Mössbauer Effect In 57Fe In Copper And The Spin‐Compensated State, B. B. Schwartz, D. J. Kim, Richard B. Frankel, N. A. Blum Feb 1968

Mössbauer Effect In 57Fe In Copper And The Spin‐Compensated State, B. B. Schwartz, D. J. Kim, Richard B. Frankel, N. A. Blum

Physics

The results of Mössbauer experiments on dilute Fe in Cu in high external magnetic fields (42–146 kOe) are presented here as evidence for significant destruction of the spin‐compensated state by a magnetic field for which μH0∼kTK, where kTK is on the order of the energy change associated with the formation of the spin‐compensated state.

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Magnetic‐Field Dependence Of The Hyperfine Field At Fe In Dilute Fe-Pd Alloys, N. A. Blum, Richard B. Frankel Feb 1968

Magnetic‐Field Dependence Of The Hyperfine Field At Fe In Dilute Fe-Pd Alloys, N. A. Blum, Richard B. Frankel

Physics

No abstract provided.

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Nonadiabatic Long-Range Forces, A. Dalgarno, Gordon W. F. Drake, G. A. Victor Jan 1968

Nonadiabatic Long-Range Forces, A. Dalgarno, Gordon W. F. Drake, G. A. Victor

Physics Publications

A general expression is obtained for the leading long-range correction to the static interaction of a slowly moving charged or neutral system at a large distance from a spherically symmetric atom, and precise estimates are presented of the magnitude for the systems H, HeA (1S1,2S1,A and A 2S3), Ne, Ar, Kr, Xe, Li+A (1S1,2S1,A and A 2S3), Li, Na, K, Rb, Cs, H2, N2, and CH4. © 1968 The American Physical Society.

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Excitation Of Auto-Ionizing Levels In Neon By Ion Impact, A. K. Edwards, M. Eugene Rudd Jan 1968

Excitation Of Auto-Ionizing Levels In Neon By Ion Impact, A. K. Edwards, M. Eugene Rudd

M. Eugene Rudd Publications

Auto-ionizing states of neutral and singly ionized neon were produced by bombarding neon gas with H+, He+, and Ne+ ions in the 150-250-keV energy range. Sixty lines in the electron spectrum were found, of which 43 have been classified into 13 Rydberg series. Ten of these series were previously unreported. Auger electrons from one- and two-vacancy states are also reported. Relative intensities of all transitions are listed.

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The Theory And Development Of A Dyeing Machine Employing The Rotary Pendulum, Ashley Paul Smith Jan 1968

The Theory And Development Of A Dyeing Machine Employing The Rotary Pendulum, Ashley Paul Smith

Master's Theses

A review of dyeing methods for carpet is made with the objective that the requirements of a new machine could be formulated. The proposal for a new machine is made in the light of the above review using a pendulum as the basic component. A theory is developed for the motion of the pendulum which is mounted on a rotating disc, and the experimental work built on theory is outlined. A prototype machine based on the rotary pendulum mechanism was used to dye impregnate carpet.

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An Experimental Determination Of The Homogeneous Nucleation Rate Of Water Vapor In Argon And Helium, Louis Benton Allen Jan 1968

An Experimental Determination Of The Homogeneous Nucleation Rate Of Water Vapor In Argon And Helium, Louis Benton Allen

Doctoral Dissertations

"An expansion type cloud chamber was used to measure the nucleation rate of water vapor in an atmosphere of helium and argon. A careful study was made of the thermodynamic characteristics during the expansion so that the nucleation data could be interpreted with reasonable accuracy and consistency. A fine wire thermocouple was used to measure the gas temperature during the course of an isentropic expansion in the dry chamber. When the finite heat capacity of the thermocouple is accounted for, it is found that there is almost perfect agreement with the temperature calculated from the equation of state and the …

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The Critical And High‐Temperature Behavior Of A Heisenberg Ferromagnet, Harry A. Brown Jan 1968

The Critical And High‐Temperature Behavior Of A Heisenberg Ferromagnet, Harry A. Brown

Physics Faculty Research & Creative Works

No abstract provided.

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Cell Model Of A Fluid. Ii. Thermodynamic Properties Of The System, Ralph G. Tross, Louis H. Lund Jan 1968

Cell Model Of A Fluid. Ii. Thermodynamic Properties Of The System, Ralph G. Tross, Louis H. Lund

Physics Faculty Research & Creative Works

In Paper I of this series (preceding paper) the model was formulated mathematically, and the solution derived in the form of an infinite series. The convergence and analyticity of the solution were investigated. It was then applied to one-, two-, and three-dimensional systems with nearest-neighbor interactions, and low-temperature series for these systems were obtained. In the present article the thermodynamics of the model are investigated. The series solution of the partition function derived in Paper I is applied to systems with interaction potentials of increasing complexity. The validity of the model is established by showing that in the appropriate limits …

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Cell Model Of A Fluid. I. Evaluation Of The Partition Function And Series Expansions, Ralph G. Tross, Louis H. Lund Jan 1968

Cell Model Of A Fluid. I. Evaluation Of The Partition Function And Series Expansions, Ralph G. Tross, Louis H. Lund

Physics Faculty Research & Creative Works

The partition function of a one-dimensional system of particles with all interactions active is formulated in terms of Ising ferromagnetic spin states. It is shown how the partition function for two- and three-dimensional systems can be obtained from the one-dimensional one by restricting the number of bonds per particle. After writing the partition function in matrix form, the operator of interest is diagonalized and its trace expressed in the form of a convenient infinite series. The series is shown to be absolutely convergent and its analytic properties are briefly investigated. It is then applied to one-, two-, and three-dimensional systems …

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Dielectric Properties Of Solid Solutions Of Bifeo₃ With Pb(Ti, Zr)O₃ At High Temperature And High Frequency, Robert Travis Smith, Gary D. Achenbach, Robert Gerson, William Joseph James Jan 1968

Dielectric Properties Of Solid Solutions Of Bifeo₃ With Pb(Ti, Zr)O₃ At High Temperature And High Frequency, Robert Travis Smith, Gary D. Achenbach, Robert Gerson, William Joseph James

Physics Faculty Research & Creative Works

Solid solutions of BiFeO3 with PbTiO3, PbTi0.5Zr0.5O3, and PbZrO3 were prepared. The crystallographic data on these solutions, which are basically perovskitic, are given. The dielectric constants of the materials were determined at a frequency of 0.53 GHz and at temperatures up to 800°C. Dielectric Curie points were found in solutions containing up to 90 mole % BiFeO3. These results leave little doubt that BiFeO3 is ferroelectric or antiferroelectric. The extrapolated Curie point for BiFeO3 is above 850°C. BiFeO3 appears more likely to be ferroelectric than …

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Optimum Spacing Of Square And Circular Coil Pairs, M. Eugene Rudd, J. R. Craig Jan 1968

Optimum Spacing Of Square And Circular Coil Pairs, M. Eugene Rudd, J. R. Craig

M. Eugene Rudd Publications

In a previous note Crownfield pointed out that the magnetic field along the axis of a coil pair is within a prescribed uniformity over a substantially longer region than that given by the Helmholtz spacing if a somewhat larger spacing is used. In the note, values of coil spacing and length of uniform field region are given for a few desired uniformities, but only for a particular "thick" coil pair, i.e., one with cross-sectional dimensions comparable to the spacing. Many coil pairs, such as those used to annul the earth's field over the region occupied by some apparatus, have cross-sectional …

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A Study Of The Physics Curriculum Of Ouachita Baptist University, James Mccarty Jan 1968

A Study Of The Physics Curriculum Of Ouachita Baptist University, James Mccarty

Honors Theses

The purpose of this paper is to compare the physics curriculum of Ouachita Baptist University with those of several other colleges with the ultimate goal of finding what changes, if any, should by made. Four colleges and universities were used for comparison. Hendrix College is a Methodist college which had an enrollment of 757 during the 1965-66 school year. State College of Arkansas is a state-supported school with 3,129 students during the same year. Little Rock University is a private school which is aided by the city of Little Rock, Arkansas. It had 2,851 students in 1965-66. Southwestern at Memphis …

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Polarization Of Compton-Scattered Gamma Rays, James G. Hudson Jan 1968

Polarization Of Compton-Scattered Gamma Rays, James G. Hudson

Honors Theses

Intermediate energy photons (approximately 0.2 mev. to 10 mev.) interact with matter of low atomic number principally through a process called the Compton effect. This process is an inelastic collision of a photon with a free electron at rest. Using the principles of conservation of energy and conservation of momentum the energy of the scattered photon can be found in terms of the incident photon energy and the angle through which it is scattered. The energy of this scattered photon is then given by E1=(EO)/(1+α(1-cos θ)) where EO is the energy of the incoming photon, …

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Nuclear Spin-Lattice Relaxation Measurements By Tone-Burst Modulation, David C. Look, Donald R. Locker Jan 1968

Nuclear Spin-Lattice Relaxation Measurements By Tone-Burst Modulation, David C. Look, Donald R. Locker

Physics Faculty Publications

No abstract provided.

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Energy Spectra Of Auto-Ionizing Electrons In Oxygen, M. Eugene Rudd, Kenneth Smith Jan 1968

Energy Spectra Of Auto-Ionizing Electrons In Oxygen, M. Eugene Rudd, Kenneth Smith

M. Eugene Rudd Publications

Experimental and theoretical data are presented showing the energy spectra of auto-ionizing electrons from atomic oxygen. The experimental data were obtained by bombarding oxygen gas with 100-keV H+ and He+ ions; the theoretical results were obtained in a close-coupling calculation which coupled the 4S, 2D, and 2P terms of the ground-state configuration of O+ in electron-O+ scattering.

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The Magnetic Dilution Problem, Harry A. Brown, William F. Parks Jan 1968

The Magnetic Dilution Problem, Harry A. Brown, William F. Parks

Physics Faculty Research & Creative Works

No abstract provided.

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A Study Of Bifeo₃ And The Hall Effect In Bifeo₃ And Cds, Fred Hoerger Taylor Jan 1968

A Study Of Bifeo₃ And The Hall Effect In Bifeo₃ And Cds, Fred Hoerger Taylor

Masters Theses

"Pure samples of BiFeO₃ were heat treated in oxygen and nitrogen atmospheres in an attempt to reduce the conductivity of the samples. Dielectric constant and dissipation factor measurements, as a function of frequency, were made to determine whether the samples had been altered. A special high temperature Hall effect apparatus was constructed. Using this apparatus an upper limit for the Hall mobility in BiFeO₃ was established. The apparatus was also used for room temperature measurements of Ga-doped CdS samples. Resistivity measurements to be used with the Hall effect results were made on both the BiFeO₃ and the CdS samples. Hot-Point …

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Mechanical Effects Of Acoustic Transients On Tobacco Mosaic Virus, Philip Edward Hamrick Jan 1968

Mechanical Effects Of Acoustic Transients On Tobacco Mosaic Virus, Philip Edward Hamrick

Theses and Dissertations

The mechanical breakage of tobacco mosaic virus (TMV) due to the action of acoustic transients has been investigated. The acoustic transients were produced by transient heating of a Prussian blue dye solution (attenuation coefficient of 1000 per cm) when a ruby laser light (20 x 106 watts) was incident on the dye surface. A quartz piezoelectric transducer was used to determine the amplitude and form of the acoustic wave. The production of acoustic waves by transient heating is discussed, and the theoretical form of the acoustic wave determined for various boundary and initial conditions are compared to the experimentally …

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The Lifetime And Effective Quenching Cross Section Of The 6²P₃/₂ State Of Thallium, Robert Charles Pickett Jan 1968

The Lifetime And Effective Quenching Cross Section Of The 6²P₃/₂ State Of Thallium, Robert Charles Pickett

Doctoral Dissertations

"The measurement of the lifetime of the metastable 6²P₃/₂ state of thallium is discussed. Measurement of time varying optical absorption by time sampling techniques is explained for the study of the decay of the metastable atom concentration following a pulsed radio frequency discharge. The decay of the thallium radiation from optically allowed states terminating on the metastable state is measured at nine different thallium densities in the afterglow of the discharge. This radiation repopulates the metastable state and is displayed on an oscilloscope. The metastable lifetime is measured as a function of the thallium density at three different r-f power …

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Cell Model Of A Fluid With Hard-Core Repulsive Long-Range Attractive Potential, Ralph G. Tross Jan 1968

Cell Model Of A Fluid With Hard-Core Repulsive Long-Range Attractive Potential, Ralph G. Tross

Doctoral Dissertations

"A model of a one-dimensional fluid is investigated in which the praticles [sic] are embedded in a cellular space grid and interact with a modified Lennart-Jones potential. It is shown that with an appropriate change in the potential function the model is also suitable for a two- or three-dimensional fluid with more restricted interactions. The man-fermion-like nature of the system resulting from the hard-rod repulsive part of the modified Lennard-Jones potential makes possible an isomorphism between occupation numbers (number operators) and spin states (spin operators) of an Ising ferromagnet, permitting a convenient mathematical formulation of the problem in terms of …

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A Study Of Bismuth Ferrate And Bismuth Manganate In Solid Solution With Lead Titanate, Harris C. Jones Jan 1968

A Study Of Bismuth Ferrate And Bismuth Manganate In Solid Solution With Lead Titanate, Harris C. Jones

Masters Theses

"A new sample holder for measuring the high frequency dielectric constant of ferroelectrics at high temperature was constructed. The new sample holder eliminated discontinuities in the slotted line and improved the electrical contact between the ceramic and brass components. Measurements of the high frequency dielectric constant of an aged sample of 90% BiFeO₃ - 10% PbTiO₃ were made as a function of temperature using the slotted line technique. The dissipation function for the aged sample was found to have a more normal behavior near the Curie point than the virgin samples previously measured. Resistivity measurements were made as a function …

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Absolute Specification Of X-Ray Spectra By Laplace Transform Analysis Of Attenuation Data, Gerald Robert Lusk Jan 1968

Absolute Specification Of X-Ray Spectra By Laplace Transform Analysis Of Attenuation Data, Gerald Robert Lusk

Masters Theses

"A well characterized, variable plate separation ion chamber was utilized as a detector to collect x-ray attenuation data for generating information on the Laplace transform predicted spectrum of a 50 KvCP conventional x-ray tube. The variable plate separation feature allows one to include a wavelength dependent correction to the detector response which is associated with the hardening of the x-ray spectrum as it traverses the attenuating material. With this correction, the conventional two-term Laplace transform was shown to approximate independently the bremsstrahlung and characteristic L radiation from the tungsten target. The detector provides an absolute statement of the target-referenced x-ray …

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Electron-Impact Lonization Cross Section In Cesium, Kaare J. Nygaard Jan 1968

Electron-Impact Lonization Cross Section In Cesium, Kaare J. Nygaard

Geosciences and Geological and Petroleum Engineering Faculty Research & Creative Works

The total ionization due to the passage of an electron beam in cesium vapor has been measured with a Tate and Smith-type apparatus. The retarding potential difference method was used in the electron gun to obtain energy resolution better than 0.1 eV. The density of Cs atoms was determined from the Taylor and Langmuir formula and also measured with a surface-ionization detector. The two methods gave the same density to within ±3% when the apparatus was in thermodynamic equilibrium with the Cs reservoir. The cross section for production of Cs+ has been determined from threshold to 100 eV. For energies …

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The Bethe-Weizsäcker Mass Formula And Lennard-Jones N-N Potentials, James Paul Wesley, Alex E.S. Green Jan 1968

The Bethe-Weizsäcker Mass Formula And Lennard-Jones N-N Potentials, James Paul Wesley, Alex E.S. Green

Physics Faculty Research & Creative Works

An elementary derivation of the Bethe-Weizscker semiempirical nuclear mass formula which is in the spirit of current views of nuclear structure, is given. Lennard-Jones potentials are assumed to act between nuclear. Thus, the major interaction between nn, pp, and np pairs is taken of the form —g/r3+h/r4, where r is the separation distance between nuclear, and g and h are constants. An additional "symmetry" interaction of the form s/r3 is assumed for np pairs. Summing the potential energy over all nucleon pairs and using the Fermi statistical estimate of the kinetic energy, the Bethe-Weizscker semiempirical mass formula is obtained directly. …

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Properties And Structure Of Some Chalcogenide Glasses, Amin Ismail Amin Abdel-Latif Jan 1968

Properties And Structure Of Some Chalcogenide Glasses, Amin Ismail Amin Abdel-Latif

Archived Theses and Dissertations

No abstract provided.

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Catalytic Decomposition Of Hydrogen Peroxide By Manganese-Doped Magnesium Hydroxide, Nabih Philobbos Kelada Jan 1968

Catalytic Decomposition Of Hydrogen Peroxide By Manganese-Doped Magnesium Hydroxide, Nabih Philobbos Kelada

Archived Theses and Dissertations

No abstract provided.

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Electronic Transitions In Diatomic Molecules, James O. Hornkohl Jan 1968

Electronic Transitions In Diatomic Molecules, James O. Hornkohl

Masters Theses

"The electronic transition moments of many band systems have been found to be linear functions of the internuclear distance. However, some band systems exhibit a quadratic variation of the transition moment. In these quadratic cases, the plots from which the variation of the transition moment is determined are based upon the approximation of the second r-centroid by the square of the first r-centroid. The square of the first r-centroid does closely approximate the second r-centroid by a simple error analysis shows that the small difference between the two is not a quantitative measure of the error introduced into the transition …

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Infrared Related Solid State Studies, Donald George Rathbun Jan 1968

Infrared Related Solid State Studies, Donald George Rathbun

Masters Theses

"Infrared reflectivity measurements have been made on single crystal CdS. Classical dispersion analysis has been used in an analysis of the data to obtain the index of refraction, the extinction index, and the dispersion parameters. These are compared with previously published results. The procedure used in this analysis has been outlined for future reference. Also, the shallow donor impurity theory has been used to numerically calculate the d±1 levels for Si and Ge. The theory is extended for the case of the impurity in the bulk semiconductor and the d₀, d±2 and, for high n, the s, p₀, …

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