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1974

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Articles 1 - 30 of 87

Full-Text Articles in Physics

Mössbauer Properties Of Synthetic Analogs Of Active Sites Of The Iron-Sulfur Proteins, Richard B. Frankel, B. A. Averill, R. H. Holm Dec 1974

Mössbauer Properties Of Synthetic Analogs Of Active Sites Of The Iron-Sulfur Proteins, Richard B. Frankel, B. A. Averill, R. H. Holm

Physics

Mössbauer spectroscopy of the synthetic tetramers [Fe4S4(SR)4]2- (R = alkyl, aryl) and the corresponding trianions obtained by one-electron reduction, when compared with available data for 4-Fe and 8-Fe iron-sulfur proteins, shows that these tetramers are electronic analogs of the active sites of the proteins.

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Kinectics Of The Ground State Transformation In Fe(Ii) (N, N -Dicyclohexylthiourea)6(Cio4)2, R. Latorre, J. A. Costamagna, E. Frank, C. R. Abeledo, Richard B. Frankel Dec 1974

Kinectics Of The Ground State Transformation In Fe(Ii) (N, N -Dicyclohexylthiourea)6(Cio4)2, R. Latorre, J. A. Costamagna, E. Frank, C. R. Abeledo, Richard B. Frankel

Physics

The high spin complex Fe(II) (N, N'-dicyclohexylthiourea)6(ClO4)6 exists in two forms which only differ in the distortion from octahedral symmetry of the environment of the Fe ion. Thermodynamic data for the transformation from one form to the other as obtained from Mössbauer spectroscopy are presented and a method to derive kinetic parameters is described.

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Antithesis In Physical Science, Russell W. Maatman Dec 1974

Antithesis In Physical Science, Russell W. Maatman

Pro Rege

No abstract provided.

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Spin-Flip In 12C (P,P') 12C Near The 9.14 Mev Doublet, John Ambani Muhanji Dec 1974

Spin-Flip In 12C (P,P') 12C Near The 9.14 Mev Doublet, John Ambani Muhanji

Masters Theses

No abstract provided.

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Science Foundations: A Science Program For The Non-Science Student. Technical Report No. 4., James Shymansky Dec 1974

Science Foundations: A Science Program For The Non-Science Student. Technical Report No. 4., James Shymansky

Educator Preparation & Leadership Faculty Works

No abstract provided.

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Repeatable Testing-A Tool For Learning Physics, David E. Golden, Robert Fuller, Donald D. Jensen Nov 1974

Repeatable Testing-A Tool For Learning Physics, David E. Golden, Robert Fuller, Donald D. Jensen

Robert G. Fuller Publications

Physics courses have traditionally used one-chance-only examinations as a probe to tell the professor how much physics each student has learned, with the result that physics examinations have been a common cause of anxiety among undergraduates.

Repeatable equivalent examinations, on the other hand, offer an alternative testing procedure which underscores material not mastered on the first examination and then allows remedial study of this material for the next examination. Furthermore, the thought that it will be possible to have another try at the examination greatly decreases the anxiety associated with examinations. While repeatable examinations are routinely used in Keller-plan courses, …

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Oer For Mixed Neutrons And Γ Rays, Robert Katz, S. C. Sharma Nov 1974

Oer For Mixed Neutrons And Γ Rays, Robert Katz, S. C. Sharma

Robert Katz Publications

A formula for the OER in a mixed field of neutrons and gamma rays (Hall, 1972a; 1972b) is given .... Our results, calculated from track structure theory (Katz and Sharma, 1973) and secondary particle-energy spectra in tissue from these neutrons (Caswell and Coyne, 1973; Dennis, 1972) are within 5 per cent of the values of Omix found from the Hall formula, when that formula is supplied with calculated values of Rn, On, and Oγ, at appropriate survival levels. Our calculations suggest that the Hall formula may be used with confidence for neutrons of …

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Molecular Model For Ice Clusters In A Supersaturated Vapor, Barbara N. Hale, P. L. M. Plummer Nov 1974

Molecular Model For Ice Clusters In A Supersaturated Vapor, Barbara N. Hale, P. L. M. Plummer

Physics Faculty Research & Creative Works

A molecular model previously applied to prenucleation water clusters is used to examine ice Ih, embryos. The canonical partition function is evaluated for clusters having from 6 to 64 water molecules. The intermolecular vibrational free energies are extrapolated to clusters containing up to 120 molecules and free energies of formation, nucleation rates, and critical supersaturation ratios are calculated and compared with experiment. For the clusters studied, the ice Ih structure appears to be much less stable at all temperatures than the more spherical clathratelike cluster.

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Second-Order Raman Scattering In Alkali Fluoride Crystals, S. L. Cunningham, T. P. Sharma, Sitaram Jaswal, M. Hass, John R. Hardy Oct 1974

Second-Order Raman Scattering In Alkali Fluoride Crystals, S. L. Cunningham, T. P. Sharma, Sitaram Jaswal, M. Hass, John R. Hardy

John R. Hardy Papers

We present theoretical and experimental second-order Raman spectra for NaF, KF, RbF, and CsF. The theoretical calculation follows the formalism of Born and Bradburn. For the lattice-dynamic calculation we use the deformation-dipole model and present comparisons with measured dispersion curves. For the polarizability calculation, we retain all eight first-neighbor and all thirty second-neighbor polarizability coefficients. We find that, in addition to all of the first-neighbor coefficients, only three of the second-neighbor coefficients are needed to obtain good agreement between the calculated and observed spectra both as regards peak positions and over-all shape. Comparison with other types of calculations are made.

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Deduction Of Asymptotic Steinmann Relations From The Regge Hypothesis, Paul Finkler, C. Edward Jones, M. Misheloff Oct 1974

Deduction Of Asymptotic Steinmann Relations From The Regge Hypothesis, Paul Finkler, C. Edward Jones, M. Misheloff

Paul Finkler Papers

The analytic structure of the double-Regge vertex, which has previously been obtained from the Steinmann relation, is derived by using a natural generalization of the Regge hypothesis.

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Sign Of The Electric Field Gradient Tensor And The Nature Of The Low Temperature Phase Transition In Fe(Pyridine)2Cl2, W. M. Reiff, Richard B. Frankel, B. F. Little, Gary J. Long Sep 1974

Sign Of The Electric Field Gradient Tensor And The Nature Of The Low Temperature Phase Transition In Fe(Pyridine)2Cl2, W. M. Reiff, Richard B. Frankel, B. F. Little, Gary J. Long

Physics

Mossbauer spectra of Fe(pyridine)2Cl2 have been determined in large external magnetic fields at room temperature and 78 K. The principal component of the electric field gradient tensor is positive and consistent with an electron in the dxy orbital. The results indicate no change in orbital ground state for the low temperature phase transition of this material.

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The Effects Of Pentachlorophenol On The Electrical Conductivity Of Lipid Bilayer Membranes, William Harvey Perman Aug 1974

The Effects Of Pentachlorophenol On The Electrical Conductivity Of Lipid Bilayer Membranes, William Harvey Perman

Dissertations and Theses

The effects of pentachlorophenol (PCP), a widely used pesticide, on the electrical characteristics of lipid bilayer membranes has been studied. When a small amount of PCP (even at a concentration of a few micromoles per liter) is present in the electrolytic solution surrounding the membrane, the electrical conductivity of the membrane significantly increases. The present work was concerned with detailed measurements of the changes in the conductivity caused by PCP under chemically controlled conditions. The experimental results were analyzed to determine the permanent species in the membrane, and an attempt was made to correlate the data with existing models of …

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16th Annual Rocky Mountain Spectroscopy Conference Aug 1974

16th Annual Rocky Mountain Spectroscopy Conference

Rocky Mountain Conference on Magnetic Resonance

Final program and abstracts from the 16th annual meeting of the Rocky Mountain Spectroscopy Conference, sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy. Held in Denver, Colorado, August 5-6, 1974.

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Cellular Survival In A Mixed Radiation Environment, Robert Katz, S. C. Sharma Aug 1974

Cellular Survival In A Mixed Radiation Environment, Robert Katz, S. C. Sharma

Robert Katz Publications

Calculations of the survival, r.b.e., and o.e.r. of human kidney cells, after sequential irradiation with gamma-rays and 14 MeV neutrons, agree well with the experiments of Railton et al., with CHO cells in these radiation environments.

Les calculs de survie, de EBR et de FAO concernant les cellules du rein humain, après des séquences d’irradiation avec des rayons gamma et des neutrons 14 MeV, concordent bien avec les expériences de Railton et ses collègues sur des cellules CHO dans des milieux comportant les mêmes radiations.

Berechnungen des Überlebens, des RBW und des OER von menschlichen Nierenzellen nach aufeinanderfolgender Bestrahlung mit …

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A Generalized Dirac Equation With Spin I, Tilahun Eneyew Aug 1974

A Generalized Dirac Equation With Spin I, Tilahun Eneyew

Masters Theses

No abstract provided.

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An Alternate Solution To The Two-Dimensional Ising Model, B. Craig Meyers Aug 1974

An Alternate Solution To The Two-Dimensional Ising Model, B. Craig Meyers

Masters Theses & Specialist Projects

An alternate solution for the two-dimensional Ising model in a zero external magnetic field is presented. Following Kaufman, the partition function is written as the trace of a certain matrix product. The trace can be evaluated by computing the determinant of a related matrix. The determinant is evaluated by finding the product of its eigenvalues; in the thermodynamic limit the result is equivalent to that found by Onsager.

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Measurement Of Neutron Differential Cross Sections Using The Associated Particle Method, Gary Eugene Rochau Aug 1974

Measurement Of Neutron Differential Cross Sections Using The Associated Particle Method, Gary Eugene Rochau

Masters Theses

No abstract provided.

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An Investigation Of Photographic Phase Holograms, Dale Lance Markham Aug 1974

An Investigation Of Photographic Phase Holograms, Dale Lance Markham

Masters Theses

No abstract provided.

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On The Reduction Of Many-Body Dielectric Theories To The Onsager Equation, John D. Ramshaw Aug 1974

On The Reduction Of Many-Body Dielectric Theories To The Onsager Equation, John D. Ramshaw

Physics Faculty Publications and Presentations

An approximate theory for the dielectric constant ℇ of a dense polar fluid was derived by Ramshaw, Schaefer, Waugh, and Deutch (RSWD). In the present article, the RSWD theory is generalized and made rigorous by another method of derivation. The result is a rigorous expression for ℇ which differs from the RSWD expression by the presence of a fluctuation term. Both the rigorous expression and the RSWD expression are then specialized to the Onsager model. It is found that the rigorous expression for ℇ reduces to the Onsager equation, but that the RSWD expression does not because the fluctuation term …

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Experiments On Dynamic Parallel Magnetism In Superfluid 3he, Richard A. Webb, R. L. Kleinberg, J. C. Wheatley Jul 1974

Experiments On Dynamic Parallel Magnetism In Superfluid 3he, Richard A. Webb, R. L. Kleinberg, J. C. Wheatley

Faculty Publications

Observations are reported of the ringing of parallel magnetization in superfluid 3He when an incremental magnetic field parallel to a steady field is suddenly turned off.

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General Geodesic Motion In The Extended Kerr Manifold, Richard H. St. John Jul 1974

General Geodesic Motion In The Extended Kerr Manifold, Richard H. St. John

Physics & Astronomy ETDs

The timelike and null geodesics in the Kerr metric describe important properties of the space surrounding a rotating black hole. The general characteristics of these geodesics, with an emphasis on those on the axis of symmetry and the equatorial plane, are found in this paper. On the axis of symmetry, the behavior of all timelike and null geodesics is completely described. The accessibility of various spaces added for geodesic completeness in the extended manifold is found by making local observations of geodesics in one coordinate patch from geodesics in another. The analysis on the equatorial plane shows that for a …

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Heavy Particles In Therapy: An Application Of Track Theory, Robert Katz, S. C. Sharma Jul 1974

Heavy Particles In Therapy: An Application Of Track Theory, Robert Katz, S. C. Sharma

Robert Katz Publications

The survival, OER, and RBE for HeLa, leukemia, and kidney cells after irradiation with 14 MeV neutrons, pion beams, and heavy ion beams dispersed by ridge filters are calculated. Simple beam models and the delta-ray theory of cellular survival are used in the calculations, which refer to a mixed radiation environment and the potential application of these irradiation systems in radiotherapy.

Résumé
Particules lourdes en thérapie; une application de la théorie de trace
On a calculé la survie, l’OER et le RBE (efficacité biologique relative) pour les cellules de HeLa, de leucémie et rénales, après l’irradiation aux neutrons de 14 …

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Ultraviolet Photosimulated Thermoluminescence Of Lithium Flouride, Martin Payne Jul 1974

Ultraviolet Photosimulated Thermoluminescence Of Lithium Flouride, Martin Payne

Masters Theses & Specialist Projects

TLD-100 (lithium fluoride) thermoluminescence dosimeters are widely employed for the detection of ionizing radiations. This paper shows that these dosimeters may also serve as practical germicidal ultraviolet radiation dosimeters. To measure ultraviolet radiation, the TLD-100 dosimeters are first exposed to 500,000 roentgens of gamma radiation and then annealed at 300°C. Subsequent dosage of ultraviolet radiation may be determined by observation of photostimulated thermoluminescence of the crystal. The presented data indicate that the thermoluminescence response is linear for exposures up to 6,000 µjoule/cm2 and independent of exposure rate from 0.1 µ watt/cm2 to above 50 µwatt/cm2. Optical …

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Eikonal Distorted-Wave Calculation For The Excitation Of H By He, Jerry Peacher, Richard H. Shields Jun 1974

Eikonal Distorted-Wave Calculation For The Excitation Of H By He, Jerry Peacher, Richard H. Shields

Physics Faculty Research & Creative Works

The eikonal distorted-wave Born approximation developed recently by Chen, Joachain, and Watson is applied to hydrogen excitation by helium impact in the intermediate-energy range. The differential and total cross sections for the excitation of the hydrogen atom to the 2s, 2p±, or 2p0 state by helium impact are presented. These results are compared to experiment and previous calculations. The differential cross section for the excitation of hydrogen to the 2s state compares well with the experimental data of Thomas and Sauers in shape and slope, but has a discrepancy in magnitude.

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Electron Attachment To Molecules In Very High Pressure Gases, Ronald Earl Goans Jun 1974

Electron Attachment To Molecules In Very High Pressure Gases, Ronald Earl Goans

Doctoral Dissertations

Introduction: The study of low energy electron attachment to molecules is of fundamental importance in both the physical and biological sciences. These processes are important in the physical sciences because many molecular parameters can be directly or indirectly determined from electron attachment studies. Such parameters include electron affinities of molecules, electron attachment rate constants and cross sections, autoionization lifetimes of transient negative ion species, bond dissociation energies, and shapes of molecular and negative ion potential energy curves. Electron attachment studies are important in biology because of the large number of low energy electrons that are produced when ionizing radiation interacts …

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Synthetic Analogs Of The Active Sites Of Iron-Sulfur Proteins. Viii. Some Electronic Properties Of [Fe4S4(Sr)4]3; Analogs Of Reduced Bacterial Ferredoxins, R. B. Frankel, T. Herskovitz, B. A. Averill, R. H. Holm, P. J. Krusic, W. D. Phillips Jun 1974

Synthetic Analogs Of The Active Sites Of Iron-Sulfur Proteins. Viii. Some Electronic Properties Of [Fe4S4(Sr)4]3; Analogs Of Reduced Bacterial Ferredoxins, R. B. Frankel, T. Herskovitz, B. A. Averill, R. H. Holm, P. J. Krusic, W. D. Phillips

Physics

One-electron reduction of the synthetic tetramers [Fe4S4(SR)4]2- (R = CH2Ph, Ph), by chemical and electrochemical methods affords the corresponding trianions. The collective results from optical, electron paramagnetic resonance, and Mössbauer spectroscopy, when compared to available data for reduced 4-Fe and 8-Fe ferredoxin proteins and super-reduced Chromatium high-potential protein, reveal that [Fe4S4(SR)4]3- are electronic analogs of the [Fe4S4(S-Cys)4] active sites of these proteins.

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Photoelectron Angular Distributions, Cross Sections, And Branching Ratios For Atomic Oxygen, Anthony F. Starace, Steven T. Manson, David J. Kennedy Jun 1974

Photoelectron Angular Distributions, Cross Sections, And Branching Ratios For Atomic Oxygen, Anthony F. Starace, Steven T. Manson, David J. Kennedy

Anthony F. Starace Publications

Theoretical calculations of the angular distribution of photoelectrons ejected from the 2p subshell of atomic oxygen for photoelectron kinetic energies 0≤ε≤30 Ry are presented using both Hartree-Fock (HF) and Herman-Skillman (HS) wave functions. Owing to the weakness of anisotropic electron-ion interactions, as evidenced by small differences between HF photoelectron phase shifts for alternative outgoing channels, the simple HS calculation of the angular-distribution asymmetry parameter is found to agree to within ≲ 0.1 with the HF calculations. Photoionization cross sections and photoelectron branching ratios have also beem computed in both the HF and HS approximation for the 2p subshell …

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Vibration Damping Characteristics Of Typical Harpsichord Strings, Jack Lee Simmons May 1974

Vibration Damping Characteristics Of Typical Harpsichord Strings, Jack Lee Simmons

Dissertations and Theses

Present-day builders of harpsichords disagree as to the use of iron or carbon-steel wire in their attempt to duplicate the tonal qualities of the early 16th century instruments. The variations in tone produced by vibrating iron and steel wires may be due, at least in part, to differences in their decay characteristics. A wire was set into vibration by placing a section in a magnetic field and passing a variable-frequency alternating current through it. A condition of resonance was established by appropriately selecting frequencies, lengths, and tensions that would simultaneously satisfy the relationship: fr = n/2L(T/p)1/2. Then measurements of decay …

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Photoelectron Angular Distributions As A Probe Of Anisotropic Electron-Ion Interactions, Dan Dill, Steven T. Manson, Anthony F. Starace May 1974

Photoelectron Angular Distributions As A Probe Of Anisotropic Electron-Ion Interactions, Dan Dill, Steven T. Manson, Anthony F. Starace

Anthony F. Starace Publications

Expressions are given for atomic photoelectron angular distributions in LS coupling in which the role of anisotropic final state electron-ion interactions emerges explicitly. Calculations of photoelectron angular distributions for atomic sulfur are presented in which these anisotropic interactions produce clear deviations from the predictions of the Cooper-Zare model. Such effects are expected to be a general feature of photoelectron angular distributions for most open-shell atoms.

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Electrical Characteristics Of Al‐Implanted Znse, B. K. Shin, Y. S. Park, David C. Look May 1974

Electrical Characteristics Of Al‐Implanted Znse, B. K. Shin, Y. S. Park, David C. Look

Physics Faculty Publications

Aluminum was implanted in ZnSe at 90 keV to a dose of 1015 ions/cm2 at room temperature. Hall‐effect and sheet‐resistivity measurements were made on the samples for various annealing conditions. The implanted layer is found to be degenerate n‐type having a sheet resistivity of ∼103 Ω/□, after annealing at 900°C for 4 h.

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