Digital Commons Network^™

Small Angle Elastic Scattering Of 1.33 Mev Photons From Lead, Chwan-Kang Chiang

Masters Theses

No abstract provided.

The 1963-64 Lake Mead Survey, J. M. Lara, J. I. Sanders, Bureau Of Reclamation

Publications (WR)

The 1963-64 Lake Mead survey was run to compute the reservoir capacity. Results of the geodetic and hydrographic surveys and sediment sampling equipment are described. The geodetic survey showed Hoover Dam subsided an average of 118 mm since 1935. Sonic sounding, photogrammetry, and crosssectional profiling methods were used to run the hydrographic survey. Reservoir area and capacity tables were generated using an electronic computer. The present lake capacity is 29,755,000 acre-ft and the reservoir surface area is 162,700 acres at elevation 1229 ft. 2,720,000 acre-ft of sediments accumulated in the lake since 1935. A unit weight of 60 Ib/cu ft …

Electron Optical Study Of A Secondary Electron Multiplier, Chang Min Shen

Dissertations and Theses

Electron orbital theory was applied to the design of the geometrical structure of an electron multiplier for an image intensifier. A special structure satisfying production requirements was studied. Electron optical calculations consisted of determining the potential distribution and tracing the electron trajectories. Liebmann's procedure was used to solve Laplace's equation with constant potentials on the multiplier electrodes as boundary conditions. The trajectories were determined by solving the equation of motion in an electrostatic field using a Runge-Kutta procedure. The initial conditions for the trajectories were the initial energies, initial positions, and the initial directions of the secondary electrons. The plotted …

A New Method In The Wkb Approximation, Raymond Pierce Engelke

Physics & Astronomy ETDs

A new WKB-like quantization rule is developed by means of a transformation method. This method makes use of a combination of a Liouville-like substitution and the Prüfer transformation. The only quality required of the potential is that it be twice differentiable on the real axis. The new quantization rule is an exact rule. However, some terms in the rule must be approximated before it can be evaluated for any particular potential function. An interesting feature of the derivation is that no asymptotic expansions are used -- unlike the usual development of the 1st order WKB quantization rule (FWKBQR). The terms …

Far-Infrared Properties Of Lattice Resonant Modes. Iv. Paraelectric Impurities, Roger D. Kirby, A.E. Hughes, A.J. Sievers

Roger Kirby Publications

We have studied the three paraelectric defect systems KCl: Li+, RbCl: Ag⁺, and NaCl: OH^- through the temperature dependence and electric field dependence of their far-infrared absorption spectra. It is found that the motional energy states for the defects in these three systems have many properties in common. In each case the impurity ion has an associated electric dipole moment and low-lying tunneling energy levels. The defects also have higher energy levels which can be attributed, at least in part, to c. m. resonant-mode motion. The KCl: Li+ tunneling levels are found to be well described by …

Molecular Orbital Calculations To Determine Stable Conformations Of The Nucleotide Deoxycytidine-3'-Monophosphate., Marvin Lawrence Chatkoff

Physics & Astronomy ETDs

Extended Huckel, semi-empirical, molecular orbital analyses were performed for deoxycytidine-31 -monophosphate and cytidine-3'-monoohosphate corresponding to single nucleotides of double helical DNA and RNA to determine whether the experimentally derived models correspond to theoretically stable configurations. The A, B, and C models of DNA, and linearly interpolated intermediate con­figurations were investigated. For RNA, the experimental A configuration, a pseudo RNA nucleotide formed from the B configuration of DNA, and intermediate conformations were used.

From the B model of DNA the base was displaced and angles adjusted until close coordinate fits were obtained at the A and C configurations. Intermediate points were …

Determination Of (N, 2n) Reaction Cross-Sections For 71ga, 106cd & 138ba Using 14 Mev Neutrons, Thomas Helm

Masters Theses & Specialist Projects

The increasing trend towards the use of activation analysis as an analytic means of identifying elements and determining their relative abundance demands more accurate values of reaction cross-sections. Accurate values of cross-sections are also important in the investigation of possible shell effects in reaction mechanisms. Many activation cross-sections for reactions produced by 14 MeV neutrons have been measured because of the relative ease with which this energy of neutrons can be produced. Low voltage accelerators are capable of producing 14. MeV neutrons by the ³H( d,n)⁴He reaction. Although many people^(1-5) have measured the (n,2n) reaction cross-sections …

Determination Of The Time Delay In The Arrival Of Jovian Signals At Opposite Ends Of A Long Baseline Fringe Synthesis Interferometer, Roger Scott

Masters Theses & Specialist Projects

In order to determine the size of the decametric sources, the technique of long baseline radio interferometry is being employed. The University of Florida at Gainesville is a pioneer in this field. In 1964, T. D. Carr introduced the procedure of recording the signals received at each end of an interferometer on magnetic tape and comparing the re-corded signals at a later time. This eliminated the necessity for transmission lines over the length of the baseline, allowing greater separation to attain higher resolution.

Photoionization Of Argon And Xenon Including Final-State Correlation, Anthony F. Starace

Anthony F. Starace Publications

Effects of final-state correlation on the photoionization cross sections for the 3p shell in argon and the 4d shell in xenon are calculated by the reaction-matrix method, starting from the Herman-Skillman model Hamiltonian, for photoelectron energies 0<~ε<~1.2 a.u. and 0<~ε<~2.52 a.u., respectively. The results for argon complement Hartree-Fock and other final-state correlation calculations; the results for xenon are the first ab initio calculations of this kind. Although length and velocity forms of the transition matrix element agree in the initial local-field approximation, they are shown to diverge necessarily when only the final state is improved.

Limited Resurrection Of The Born Approximation, Paul Finkler

Paul Finkler Papers

It is shown that the ordinary Born approximation for pn and pp̅ charge-exchange scattering correctly accounts for (1) the shape of the forward peak for 0 ≤ (-t) ≤ µ²/2 at P_L = 8 GeV/c, and (2) the energy dependence of the cross sections at t=0 in the energy range P_L,=2—8 GeV/c. This result is analogous to the well-known success of the electric Born approximation in Π⁺ photoproduction. It is then shown that the simplest interpretation of this surprising result within the framework of Regge-pole theory is in terms …

A Numerical Solution To The Problem Of Rotation Near The Ground, David D. Chen

Mechanical & Aerospace Engineering Theses & Dissertations

No abstract.

Analytic Approach To Electron Correlation In Atoms, Ronald White, Frank Stillinger

Center for Advanced Mineral and Metallurgical Processing (CAMP)

A novel perturbative treatment of electron correlation in N‐electron atoms is devised. The unperturbed starting point is a central‐force “hydrogenic” problem in the full dN‐dimensional configuration space (d = dimensionality). The central potential in this solvable “hydrogenic” problem is obtained by averaging the actual electron–electron and electron–nucleus potentials over all dN − 1dN − 1 hyperspherical polar angles in the configuration space. The relevant projected Green's functions are computed for the ground states of the model one‐dimensional two‐electron atom (with delta function interactions), as well as for the real three‐dimensional helium isoelectronic sequence. The corresponding first‐order wavefunctions exhibit weakly singular …

-Ray Induced Luminescence Of Ruby, Wayne Cooke

Masters Theses & Specialist Projects

Since the advent of the laser there has appeared a multitude of scientific papers describing the various parameters that would affect the lasing action of the ruby laser. Many investigations have been carried out to determine the efficiency of the R-line fluorescence in ruby: however very little work has been done concerning the X-ray-induced luminescence of ruby.

Certainly the applications to laser technology would be of sufficient importance to merit a study of ruby under continuous irradiation, although this was not the main stimulus that motivated this investigation. The original program of study was undertaken to determine if there existed …

Propagation Of Ultrasound In Plastic Crystals, Carl E. Scheie

Physics & Astronomy ETDs

The study of the organic solid state, and in particular of plastic crystals, is a relatively new branch of physics (1,2). Timmermans first surmised the existence of these solids from the anomalous values of the entropies of fusion. The solids possess many of the characteristics of liquids. They are easily deformed by pressure and they show dielectric properties that can be described on the basis of rotation of the molecules in their lattice positions. Still they have a definite crystal structure. Thus, even though the molecules are not symmetric, they appear to be to some degree because of the rotation. …

Hot Electron Injection Into Liquid Argon From A Tunnel Cathode, Pavel Smejtek, David G. Onn, M. Silver, P. Kumbhare

Physics Faculty Publications and Presentations

Hot electrons from a tunnel cathode have been injected into liquid argon (99.998% pure) at 87°K. The current vs voltage characteristics indicate that the injected hot electrons thermalize very slowly, losing their energy only by elastic scattering processes and finally by capture by the dilute impurities. The deduced thermalization time and distance are very long compared with that in helium, where bubble formation is responsible for energy loss.

Asymptotic Behavior Of Fluid Jets, Ronald Walter Godfrey

All Master's Theses

In this paper we shall consider the steady-state, two dimensional, irrotational flow of an inviscid, incompressible fluid under gravity.

An Investigation Of A Gas Measurement Technique Employing Ultraviolet Excitation, Alphonso Vincent Diaz

Physics Theses & Dissertations

A study was undertaken to determine the general applicability of a temperature measurement technique which uses the fluorescence stimulated by a vacuum ultraviolet continuum as the indicator. This study was directed toward determining the temperature of nonradiating carbon monoxide. A number of ultraviolet radiation sources which produced high intensity in the region of l,150 A were investigated. This study led to the conclusion that the technique was not applicable to measurements in carbon monoxide within the present limits of' detectability.

Elastic Scattering Of 1.33 Mev Gamma Rays From Uranium, Joan Sue De Vries

Masters Theses

No abstract provided.

A Study Of Defects In Platinum Using Positron Annihilation, Clarence D. Esseltine

Masters Theses

No abstract provided.

A Direct Measurement Of The Ratio Of The Reaction Cross Sections For Two-Photon And Three-Photon Annihilation Of A Positron And An Electron In Aluminum, Jeffrey Ira Siegel

Masters Theses

No abstract provided.

Asymptotic Lattice Displacements About Point Defects In Cubic Metals, John W. Flocken, John R. Hardy

John R. Hardy Papers

We have calculated the asymptotic displacements (a) about a single vacancy in Al, Na, K, and Li, (b) about a single interstitial Cu atom in a Cu host lattice, and (c) about a unit single double force along a (100) direction in A1 and Cu. These calculations were made using the asymptotic equations of the method of lattice statics which, in its full form, is based on the Fourier transformation of the direct-space force equations between the detect and the host atoms in a large "supercell" of the lattice. Results were also obtained for each of the defect types in …

Calculations Of The Intensity Of X-Ray Diffuse Scattering Produced By Point Defects In Cubic Metals, John W. Flocken, John R. Hardy

John R. Hardy Papers

We have calculated isointensity profiles for the diffuse X-ray scattering associated with certain types of defects in Cu, Al, Na, K, Li, and a theoretical model lattice. These profiles were computed for high-symmetry planes very close to reciprocal-lattice points of the (S, 0,0), (S,S,0), and (S,S,S) type. Both cubic and double-force defects were treated. The calculations were done using a technique presented by Kanzaki for the theoretical model lattice. Kanzaki's general conclusion that cubic defects produce leminiscate profiles and that double-force defects produce ellipsoidal profiles is confirmed for all the material studied. Our profiles for the model lattice agree with …

Stress-Induced Angular Momentum Quenching In Mgo: Fe2+ As Observed By Mössbauer Spectroscopy, J. Chappert, A. Misetich, Richard B. Frankel, N. A. Blum

Physics

Under the influence of a suitable uniaxial stress, the quenching of the electronic angular momentum of the low-lying threefold degenerate Γ_5g level of Fe²⁺ in cubic MgO has been observed by Mössbauer spectroscopy. The result is consistent with Ham's model for the appearance of a quadrupole doublet at low temperatures. A value for the strain coefficient of Fe²⁺ in MgO has been obtained: G₁₁=585 cm^-1.

Rayleigh Hysteresis Shape: Its Relationship To Displacement Distance Of A Single Domain Wall In 50% Ni–Fe, R. C. Woodbury, M. R. Hunt

Faculty Publications

The need to measure the displacement distance of domain walls from equilibrium for very weak alternating fields (H ≪ coercive force) in bulk magnetic material has prompted a study of the possible use of the opening of the Rayleigh hysteresis loop to indicate the amount of wall displacement. This paper contains (1) a review of the theoretical relationship between hysteresis shape and the displacement distance of a domain wall, based upon defect-energy models of Rodbell and Bean, and Baldwin; and (2) an experimental approach which provides a measure of the wall displacements versus hysteresis shape for 50% Ni–Fe tape. Discrepancies …

Existence Of Fixed Poles And Their Role In Conspiracy, Paul Finkler

Paul Finkler Papers

It is shown that unitarity allows fixed poles at certain nonsense points of either right or wrong signature. The conditions for the existence of these poles are found. These conditions are then used to locate the poles allowed in hadronic reactions. Possible mechanisms for the poles are considered. It is then argued that fixed poles provide the most natural explanation of the conspiracy phenomenon.

Fermi Surface Of Ausb2. I. High-Field Galvanomagnetic Effects, J. Ahn, David J. Sellmyer

David Sellmyer Publications

High-field galvanomagnetic effects have been investigated in the pyrite structure metallic compound AuSb₂ in fields up to 150 kG. The resistance ratios of the samples [ρ(295°K)/ρ(4.2°K)] were as high as 520. The results indicate that AuSb₂ is a compensated metal and that its Fermi surface supports open orbits in 〈100〉, 〈110〉, and 〈112〉 directions. At fields higher than about 50 kG, the tendency toward saturation caused by the open orbits changes to a field dependence approaching quadratic, and rather large-amplitude quantum oscillations in the magnetoresistance appear. This behavior is explicable in terms of a loss of the open …

Time Saving In Measurement Of Nmr And Epr Relaxation Times, David C. Look, Donald R. Locker

Physics Faculty Publications

By producing a train of absorption or dispersion signals (continuous‐wave magnetic resonance) or free induction decays (pulsed magnetic resonance) it is possible to save time in spin‐lattice relaxation measurements due to the fact that it is not necessary to wait for equilibrium magnetization before initiating the train. The relaxation time may be calculated from the train according to a simple rapidly converging iteration.

Differential Cross Section For Charged A₁ Photoproduction Using The Regge Exchange Formalism, Keiji Kikkawa, Barbara N. Hale

Physics Faculty Research & Creative Works

The Regge-pole formalism is applied to the calculation of the differential cross section for A₁⁺ photo-production in the region |t_min| < -t < 10µ². The p, A₁, A₁-daughter, A₂, and π trajectory contributions are considered, and use is made of chiral dynamics to estimate the unknown coupling constants. We find that the π and the A₂ trajectories provide the dominant contributions.

Proposed Thermodynamic Pressure Scale For An Absolute High-Pressure Calibration, Daniel L. Decker, J. Dean Barnett

Faculty Publications

The field of high pressure has developed rapidly over the past few years to a point where relatively sophisticated experiments are being attempted. In many experiments it is no longer sufficient to qualitatively estimate the pressure or to base conclusions on experimental results tied to an empirical pressure parameter. One desires to accurately know the pressure dependence of physical quantities related to a true thermodynamic scale.

Projected Hartree Product Wavefunctions. V. Density Matrices And Operators Containing Spin, Gordon A. Gallup

Gordon Gallup Publications

Formulas are given to allow the calculation of the various spin components of the first-order density and transition density matrices from one spatial component of a pure spin-state wavefunction and certain reduced operators. Similar expressions are given for the second-order density for singlet and doublet systems. These results are useful for the calculation of matrix elements of operators containing the spin. ©1970 American Institute of Physics