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1981

Physics

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Articles 1 - 30 of 97

Full-Text Articles in Physical Sciences and Mathematics

Precision Expansion Cloud Chamber For Homogeneous Nucleation Studies, John L. Schmitt Dec 1981

Precision Expansion Cloud Chamber For Homogeneous Nucleation Studies, John L. Schmitt

Physics Faculty Research & Creative Works

The author describes an expansion cloud chamber for the study of the nucleation of a single component vapor (homogeneous nucleation). The design draws on the many years of experience in this Center in construction of chambers for homogeneous nucleation of water. Design features of the chamber are exact control of temperature (±0.03° C), pressure (±0.5 mm Hg), and automatic control of cycling. Construction features are all construction materials are stainless steel, glass, or fluorocarbon plastics; the piston seal is a very flexible welded stainless-steel bellows; the chamber can be made very clean by heating under vacuum, and it is compatible …

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Reply (To "Comment On 'The Absolute Scattering Cross Section At50 Mhz Of Equatorial Electrojet Irregularities' By Farley Et Al." By N. D'Angelo), D. T. Farley, Bela G. Fejer Dec 1981

Reply (To "Comment On 'The Absolute Scattering Cross Section At50 Mhz Of Equatorial Electrojet Irregularities' By Farley Et Al." By N. D'Angelo), D. T. Farley, Bela G. Fejer

Bela G. Fejer

No abstract provided.

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Contours Of Constant Principal Angle And Constant Principal Azimuth In The Complex Ε Plane, R. M.A. Azzam Dec 1981

Contours Of Constant Principal Angle And Constant Principal Azimuth In The Complex Ε Plane, R. M.A. Azzam

Electrical Engineering Faculty Publications

For light reflection at a planar interface between two homogeneous isotropic media with complex relative dielectric function ε, we show that the constant-principal-angle contours are a family of semicircles, whereas the constantprincipal-azimuth contours are a family of (segments of) hyperbolas in the complex ε plane. We also find the exact envelope curve of both families and hence determine the domain of the ε plane of multiple (three) principal angles that is bougded by the envelope curve and the real axis. A unique and peculiar interface with ε = (5 - j√2)/27 is shown to have three coincident principal angles of …

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Suitability Of Egyptian Raw Materials For The Production Of Cement Clinker Using The Dry Process, Lamia Rifaat Ismail Dec 1981

Suitability Of Egyptian Raw Materials For The Production Of Cement Clinker Using The Dry Process, Lamia Rifaat Ismail

Archived Theses and Dissertations

No abstract provided.

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Crystal Perfection Of Hgi2 Studied By Neutron And Gamma-Ray Diffraction, W. (William) B. Yelon, R. W. Alkire, M. M. Schieber, L. Van Den Berg, S. E. Rasmussen, H. Christensen, J. R. Schneider Dec 1981

Crystal Perfection Of Hgi2 Studied By Neutron And Gamma-Ray Diffraction, W. (William) B. Yelon, R. W. Alkire, M. M. Schieber, L. Van Den Berg, S. E. Rasmussen, H. Christensen, J. R. Schneider

Physics Faculty Research & Creative Works

The crystalline perfection of wire sawn pieces of vapor grown single crystals of mercuric iodide was compared with the perfection of (00l) cleaved sections of the same crystal from which nuclear radiation detectors have been fabricated. The crystalline perfection was studied using neutron and gamma-ray diffraction rocking curves. Most of the gamma-ray data were obtained using a high intensity source of 153Sm gamma rays with a wavelength of λ = 0.12 Å. Some of the data were obtained using highly penetrating 198Au gamma rays with a shorter wavelength of λ = 0.03 Å. The neutrons had a wavelength of λ …

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Hot-Wire Anemometer Behaviour In Low Velocity Air Flow, P. J. Christman, Josef Podzimek Dec 1981

Hot-Wire Anemometer Behaviour In Low Velocity Air Flow, P. J. Christman, Josef Podzimek

Physics Faculty Research & Creative Works

The behavior characteristics of a commercially available hot-wire anemometer have been examined in the presence of low velocities, lwss than 0.1 m/s for the most part, and in both horizontal and vertical air flows. The orientation of the probe in a horizontal flow has been found to have a definite effect on velocity measurements, and a lower limit to the reliable application of hot-wire anemometry has been evaluated for a particular type of probe. Vertical flow measurements have resulted in the discovery of the magnitude of natural convective velocity, and a possible method for determining the dimensions of the temperature …

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Bilinear Equation For The Cylinder With Overlap And The Pomeron Residue, Paul Finkler, C. Edward Jones Nov 1981

Bilinear Equation For The Cylinder With Overlap And The Pomeron Residue, Paul Finkler, C. Edward Jones

Paul Finkler Papers

A bilinear integral equation for the cylinder is derived within the meson sector of the theory of dual topological unitarization. The equation is more general than conventional linear cylinder equations since it includes regions of phase space in which produced particles overlap in rapidity. The equation also permits a simple treatment of phase space which corresponds to that of the planar bootstrap problem. Two classes of solutions are found, only one of which results in the Pomero'n-f identity. This treatment also indicates that the residue of the Pomeron may be twice as large as that suggested by earlier calculations …

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Statistics Of Multicharge Centers In Semiconductors - Applications, David C. Look Nov 1981

Statistics Of Multicharge Centers In Semiconductors - Applications, David C. Look

Physics Faculty Publications

A general formula is derived for the electron occupation numbers appropriate for multicharge centers in semiconductors, including excited states. The results are used to rederive and generalize several formulas of interest in the literature, in order to show exactly how the degeneracies of individual states enter in. Particular attention is paid to certain subjects which are sometimes confusing, such as how the statistics of band states differ from those those of localized states. Another subject of much recent interest, negative-U centers, is dealt with in some detail. We show how the dependence of the average occupation number on Fermi …

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Miiiikan Award For 1981, Robert Fuller Nov 1981

Miiiikan Award For 1981, Robert Fuller

Robert G. Fuller Publications

In conclusion, for his notable and creative contributions to physics teaching, in particular how he has alerted us to the implications of our cultural assumptions, how he has found interesting physics everywhere, and how he has valued the humanity of physics, the American Association of Physics Teachers presents to Albert A. Bartlett the 1981 Robert A. Millikan Award.

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Magnetic And Electrical Properties Of Iron-Nickel-Chromium-Metalloid Glasses, H. Sadate-Akhavi, George C. Hadjipanayis, David J. Sellmyer Nov 1981

Magnetic And Electrical Properties Of Iron-Nickel-Chromium-Metalloid Glasses, H. Sadate-Akhavi, George C. Hadjipanayis, David J. Sellmyer

David Sellmyer Publications

The magnetic and electrical properties of amorphous (Fe1-xNix)78-yCrySi10B12 alloys have been measured between 4.2 and 300 K. Alloys with x≤0.9 and y=5 order ferromagnetically. High-field magnetization measurements show saturation in moderate fields suggesting a relatively high value of magnetic anisotropy which was estimated to be K≃106 erg/cm3. The magnetization at low temperatures follows a T3/2 law leading to a spin-wave stiffness coefficient D≃90 meV Å2. The x=1, y=5 alloy behaves like a "cluster glass" with a cluster ordering temperature around 20 …

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Massive Neutrinos And The Stellar Stopping Power Via The Neutrino Magnetic Moment, P.T. Leung, M. L. Rustgi, J. E. Turner, Werner Brandt Nov 1981

Massive Neutrinos And The Stellar Stopping Power Via The Neutrino Magnetic Moment, P.T. Leung, M. L. Rustgi, J. E. Turner, Werner Brandt

Physics Faculty Publications and Presentations

An exact expression is derived within the high-Q approximation for the spectrum of energy losses of neutrinos interacting via their magnetic moment with electrons. A formula for the stopping power of matter for neutrinos is derived and applied to the study of the solar neutrino anomaly. The total inelastic cross section is given. An upper limit is deduced for the neutrino magnetic moment from the antineutrino spectrum as recently parameterized by Lee (1979). It confirms the bound reported by Cowan and Reines. The distance for stellar neutrinos to thermalize by the interactions studied here, through encounters with stars is found …

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Explicit Determination Of Thickness Of A Transparent Film On A Transparent Substrate From Angles Of Incidence Of Equal P And S Reflectivities, R. M.A. Azzam Oct 1981

Explicit Determination Of Thickness Of A Transparent Film On A Transparent Substrate From Angles Of Incidence Of Equal P And S Reflectivities, R. M.A. Azzam

Electrical Engineering Faculty Publications

No abstract provided.

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Existence Of The Dielectric Constant In Dipolar Fluid Mixtures, John D. Ramshaw, Norman D. Hamer Oct 1981

Existence Of The Dielectric Constant In Dipolar Fluid Mixtures, John D. Ramshaw, Norman D. Hamer

Physics Faculty Publications and Presentations

The existence of the dielectric constant epsilon is investigated for fluid mixtures of rigid polar molecules. The investigation is performed using the functional-derivative formalism for mixtures, and is closely analogous to that previously carried out for pure dipolar fluids (J. Chem. Phys. 68, 5199 (1978)). Sufficient conditions for the existence of epsilon are obtained in terms of the direct correlation function matrix c/sub alphabeta/(12). It is found that epsilon exists if c/sub alphabeta/(12) depends only on relative positions and orientations, and becomes asymptotic to -theta/sub alphabeta/(12)/kT at long range, where theta/sub alphabeta/(12) is the dipole--dipole potential between a molecule of …

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Orientation Of Atoms Excited By Charged Particles At High Impact Energies, Don H. Madison, Kieth H. Winters Oct 1981

Orientation Of Atoms Excited By Charged Particles At High Impact Energies, Don H. Madison, Kieth H. Winters

Physics Faculty Research & Creative Works

A perturbation-expansion approach is used to examine the sign of the orientation vector as a function of scattering angle and projectile charge. It is shown that for small angles, the sign of the orientation vector is different for oppositely charged projectiles consistent with the prediction of the classical grazing model. At large angles, on the other hand, the orientation vector for oppositely charged projectiles is shown to have the same sign.

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Glory In Optical Backscattering From Air Bubbles, Dean S. Langley, Philip L. Marston Sep 1981

Glory In Optical Backscattering From Air Bubbles, Dean S. Langley, Philip L. Marston

Physics Faculty Publications

Observations of light backscattered from air bubbles in a viscous liquid demonstrate an enhancement due to axial focusing. A physical-optics approximation for the cross-polarized scattering correctly describes the spacing of regular features observed. The non-cross polarized scattering is not adequately described by a single class of rays.

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The Absolute Scattering Cross Section At 50 Mhz Ofequatorial Electrojet Irregularities, D. T. Farley, H. M. Ierkic, Bela G. Fejer Sep 1981

The Absolute Scattering Cross Section At 50 Mhz Ofequatorial Electrojet Irregularities, D. T. Farley, H. M. Ierkic, Bela G. Fejer

Bela G. Fejer

We have made carefully calibrated radar scattering measurements by using the large 50-MHz Jicamarca antenna. Typical results from the altitudes of maximum echo power for the vertically directed beam are σradar ∼1–2 × 10−10 m−1 for strong daytime electrojet conditions with type 1 irregularities present, with values a factor of 10 or so smaller during moderate conditions when only type 2 are observed. These cross sections, which are very large in comparison with those for incoherent scatter (σradar ≃5 × 10−18 m−1 for an electron density of 1011 m−3), are not nearly large enough, however, to cause pseudo-absorption events on …

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Optical Pulse Compression In A Cholesteric Liquid Crystal, D. N. Ghosh Roy, D.V.G.L.N. Rao, H. Bronk Sep 1981

Optical Pulse Compression In A Cholesteric Liquid Crystal, D. N. Ghosh Roy, D.V.G.L.N. Rao, H. Bronk

Physics Faculty Publications

A 20‐ns laser pulse is compressed to nearly 2.5 ns in a 10‐cm‐long sample of liquid‐crystal cholesteryl oleate in the isotropic phase. Pulse compression in a length as short as only 5 cm has been observed. A semiquantitative explanation is given in terms of stimulated Brillouin scattering.

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Theoretical Study Of The Structural Phase Transition In Rbcaf3, L. L. Boyer, John R. Hardy Sep 1981

Theoretical Study Of The Structural Phase Transition In Rbcaf3, L. L. Boyer, John R. Hardy

John R. Hardy Papers

We have made a first-principles study of the structural phase transition at Tc = 193 K in RbCaF3, using interionic potentials derived by the Gordon-Kim approach, and a new extension of the quasiharmonic approximation for the free energy. The transition is caused by instability of a triply degenerate R-point vibration which leads to a coordinated rotation of the CaF6 octahedra. We find that, as the lattice contracts, the quasiharmonic frequency of the R-point vibrations becomes imaginary at approximately 1280 K: Below this temperature the static lattice energy, as a function of CaF6 rotation, has a …

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Time-Dependent Direct Correlation Function, John D. Ramshaw Sep 1981

Time-Dependent Direct Correlation Function, John D. Ramshaw

Physics Faculty Publications and Presentations

A time-dependent direct correlation function (TDDCF) is defined and discussed. The definition (which differs from that proposed by Percus and Yevick) is motivated by linear response theory. The TDDCF consequently has a functional-derivative or stimulus-response interpretation closely analogous to that of the static direct correlation function. Mean-field considerations suggest that the TDDCF separates into a term which is simply related to the pair potential and a spatially shorter-ranged remainder. This behavior is confirmed in the Vlasov-Zwanzig approximation.

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23rd Rocky Mountain Conference Aug 1981

23rd Rocky Mountain Conference

Rocky Mountain Conference on Magnetic Resonance

Abstracts and meeting program from the 23rd annual meeting of the Rocky Mountain Conference, co-sponsored by the Rocky Mountain Section of the Society for Applied Spectroscopy and the Rocky Mountain Chromatography Discussion Group. Held in Denver, Colorado, August 2-6, 1981.

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The Water Monomer On The Prism Face Of Ice And Above A Four Layer Ice Basal Face Ledge: An Effective Pair Potential Model, Barbara N. Hale, Jerry Kiefer, Carolyn A. Ward Aug 1981

The Water Monomer On The Prism Face Of Ice And Above A Four Layer Ice Basal Face Ledge: An Effective Pair Potential Model, Barbara N. Hale, Jerry Kiefer, Carolyn A. Ward

Physics Faculty Research & Creative Works

A previous study of the water monomer on the basal faces of ice is extended to consider the interaction of the water molecule with a rigid prism face of ice and with an ice basal face ledge. The effective central force H2O-H2O potentials of Stillinger and Rahman are used to generate maximal binding energy surfaces for the H2O adsorbed on the sample substrates. The results indicate that the prism face of ice binds the water molecule more strongly than the basal faces, and the step on the basal face serves to expose high binding …

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A Study Of The Films Produced By The Aluminum/Water Reaction Using Rutherford Backscattering Spectroscopy, Reed L. Shilts Aug 1981

A Study Of The Films Produced By The Aluminum/Water Reaction Using Rutherford Backscattering Spectroscopy, Reed L. Shilts

Masters Theses

This work compares the action of pure water to various aqueous electrolytes on aluminum surface film formation at about 100°C. The electrolytes were pure water with various inhibitor ions added. The ions were nitrate, tungstate, borate, molybdate, silicate, phosphate, a mixture of nitrate and molybdate, and a mixture of silicate and molybdate. The investigative technique was Rutherford backscattering spectroscopy (RBS) using 2 MeV alpha particles with an annular detector set at 180 degrees for maximum elemental resolution. RBS was chosen for this investigation because it offers in an easily interpretable manner a relatively fast and semi-quantitative method of analysis of …

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Detector Geometry For Cascade Photon Experiments, Roger Minoru Munechika Aug 1981

Detector Geometry For Cascade Photon Experiments, Roger Minoru Munechika

Masters Theses

An observation of cascading optical photons can be used to determine an absolute excitation cross section for the intermediate state without the need of standard lamp calibration. In order to reduce the data an angular correlation function and an angular distribution function must be known. These functions depend on the alignment of the upper excited state and the polarization of the light emitted in the lower part of the cascade. However, at certain angles of observation the values of the required functions are known regardless of the alignment or polarization. A computer search is done to find these angles for …

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The Creation Of Holograms Utilizing Fiber Optics, Abdul Rahim Omar Aug 1981

The Creation Of Holograms Utilizing Fiber Optics, Abdul Rahim Omar

Masters Theses

Holography involves the interference of two light beams, namely a reference beam and an object beam. Instead of the conventional method using beam splitters and mirrors to direct the light path, fiber optic bundles are used and high quality holograms have been produced. When fiber optic bundles are used, a spatial filter is not needed to produce a "clean" beam of light for the reference beam. Fiber optic bundles also provide greater flexibility of illumination for the object beam and/or fir the reference beam. Also, it is easier to illuminate the object from many directions. Finally, the distance from the …

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Comment On Particle Mixing And Delta-I= 3/2 Terms In Non-Leptonic Weak Decays, Br Holstein Jul 1981

Comment On Particle Mixing And Delta-I= 3/2 Terms In Non-Leptonic Weak Decays, Br Holstein

Barry R Holstein

A recent paper by Gusbin concludes that ΔI=3/2 terms in K→πη can substantially modify particle-mixing contributions to K+→π+π0. Using techniques which can successfully reproduce the experimental features of the K→ππ decays, we argue that this seems unlikely.

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Macroscopic Quantum Tunneling In 1-Μm Nb Josephson Junctions, Richard F. Voss, Richard A. Webb Jul 1981

Macroscopic Quantum Tunneling In 1-Μm Nb Josephson Junctions, Richard F. Voss, Richard A. Webb

Faculty Publications

The probability distributions for switching out of the superconducting state of low-cur-rent-density 1-μm Nb Josephson junctions with capacitance ≈ 0.1 pF have been measured as a function of temperature T down to 3 mK. Below 100 mK the distribution widths become independent of T. The results are in excellent agreement with predictions for the quantum tunneling of the (macroscopic) junction phase that include the reduction of tunneling rates due to dissipation.

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Photoionization Of The 4D10 Subshell Of Cadmium: Photoelectron Angular Distributions And Polarization Of Fluorescence Radiation, Constantine E. Theodosiou, Anthony F. Starace, B.R. Tambe, Steven T. Manson Jul 1981

Photoionization Of The 4D10 Subshell Of Cadmium: Photoelectron Angular Distributions And Polarization Of Fluorescence Radiation, Constantine E. Theodosiou, Anthony F. Starace, B.R. Tambe, Steven T. Manson

Anthony F. Starace Publications

Relativistic Dirac-Fock calculations are presented for the photoelectron angular distribution asymmetry parameter β corresponding to 4d-subshell photoionization in Cd and for the linear polarization PL of the subsequent fluorescence radiation, for photon energies less than 185 eV. Near threshold, our results for β lie lower than previous relativistic Dirac-Slater and nonrelativistic many-body-perturbation-theory (MBPT) calculations. The agreement with very recent measurements by Heinzmann and Schönhense is very good. Our calculations show that PL (2D5/2→2P3/2)=-0.059 and -0.058 at incident photon energies hν=40.2 and 45.6 eV, respectively. These results lie …

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Exactly Soluble Ising Models On Hierarchical Lattices, Miron Kaufman, Robert B. Griffiths Jul 1981

Exactly Soluble Ising Models On Hierarchical Lattices, Miron Kaufman, Robert B. Griffiths

Miron Kaufman

Certain approximate renormalization-group recursion relations are exact for Ising models on special hierarchical lattices, as noted by Berker and Ostlund. These lattice models provide numerous examples of phase coexistence and critical points at finite temperatures, including cases of continuously varying critical exponents and phase transitions without phase coexistence. The lattices are, typically, quite inhomogeneous and may possess several inequivalent limits as infinite lattices.

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Negative Acceleration Components For A Relativistic Particle, James A. Lock Jul 1981

Negative Acceleration Components For A Relativistic Particle, James A. Lock

Physics Faculty Publications

Newtonian acceleration is considered in the light of special relativity theory with the result that the component of acceleration in the direction of an arbitrary applied force is always positive.(AIP)

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Implications Of Nuclear Parity Non-Conservation, Jf Donoghue, Br Holstein Jun 1981

Implications Of Nuclear Parity Non-Conservation, Jf Donoghue, Br Holstein

Barry R Holstein

From recent developments in the area of nuclear parity nonconservation we extract evidence for (1) SU(3) /soft-pion breaking in weak pionic vertices, and (2) larger values of quark masses than have been used in previous evaluations of "penguin" matrix elements.

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