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Vacuum ultraviolet electronic properties of liquids. Annual progress report, 1 November 1979-31 October 1980

Description: Areas covered are: optical and dielectric properties of hexamethyl-phosphoric triamide; photoemission from uv irradiated liquids; photon and photoelectron mean free paths in liquids; properties of Kapton films; and uv transmission of polycyclic organic molecules. (GHT)
Date: January 1, 1980
Creator: Painter, L.R.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Diffusion of Slow Electrons in Gases

Description: The properties of electrons in a gas and an external electric field, e.g., agitation velocity, free path, energy lost per collision, and collision cross sections, were determined for electrons of energy less than 2 ev in a large number of gases. The computations were made from previously measured values for Townsend's energy factor or the ratio of electron agitation energy to molecule thermal energy. Results are presented for hydrogen, nitrogen, carbon dioxide, methane, ethylene, cyclopropane, … more
Date: October 24, 1961
Creator: Forester, D. W. & Cochran, L. W.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries Government Documents Department
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Two-particle correlations in nuclear collisions. [800 MeV/A]

Description: Two-particle correlations in proton-nucleus and nucleus-nucleus collisions were measured with beams of 800 MeV/A at the Berkeley Bevalac to study the reaction mechanism in more detail. Results were obtained that give information about the mean free path of protons in the nucleus, the contribution of the single-knock-out process in the collisions between equal-size nuclei, and the nuclear shadowing effect in collisions with a heavy target nucleus. 3 figures. (RWR)
Date: July 1, 1980
Creator: Tanihata, I.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Derivation of the high field semiconductor equations

Description: Electron and hole densities evolve in x-z phase space according to Boltzmann equations. When the mean free path of the particles is short and electric force on the particles is weak, a well-known expansion can be used to solve the Boltzmann equation. This asymptotic solution shows that the spatial density of electrons and holes evolves according to diffusion-drift equations. As devices become smaller, electric fields become stronger, which renders the Basic Semiconductor Equations increasingly … more
Date: January 1, 1991
Creator: Hagan, P. S.; Cox, R. W. & Wagner, B. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Observation of anomalous reaction mean free paths of nuclear-projectile fragments in research emulsion from 2 A GeV heavy-ion collisions

Description: From an analysis of 1460 projectile fragment collisions in nuclear research emulsion exposed to 2.1 A GeV /sup 16/O and 1.9 A GeV /sup 56/Fe at the Bevalac, evidence is presented for the existence of an anomalously short interaction mean free path of projectile fragments for the first several cm after emission. The result is significant to beyond the 3 standard deviation confidence level.
Date: July 1, 1981
Creator: Karant, Y.J.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Monte Carlo techniques for analyzing deep penetration problems

Description: A review of current methods and difficulties in Monte Carlo deep-penetration calculations is presented. Statistical uncertainty is discussed, and recent adjoint optimization of splitting, Russian roulette, and exponential transformation biasing is reviewed. Other aspects of the random walk and estimation processes are covered, including the relatively new DXANG angular biasing technique. Specific items summarized are albedo scattering, Monte Carlo coupling techniques with discrete ordinates and… more
Date: January 1, 1985
Creator: Cramer, S. N.; Gonnord, J. & Hendricks, J. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Interaction of low-energy electrons and positrons with condensed matter: Stopping powers and inelastic mean free paths from optical data

Description: An optical-data model'' is described for evaluating energy loss per unit pathlength and inelastic mean free path for low-energy electrons and positrons ({approx lt} 10 keV) from optical data on the medium of interest. Exchange between the incident electron and electrons in the medium is included. Results from the optical-data model are compared with previous theoretical calculations. 15 refs., 6 figs., 2 tabs.
Date: January 1, 1989
Creator: Ashley, J.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Nuclear collision at E/A approx. = T/sub F/

Description: A qualitative discussion of nuclear collisions in which the bombarding energy per nucleon is up to the order of the Fermi kinetic energy is made. The significant processes encountered as bombarding energy increases from a few MeV to energies large in comparison with rest energies are sketched. An estimate of the nucleon mean free path is obtained, and nuclear dynamics at moderate excitation is discussed. At the higher bombarding energies, prompt emission of one or several particles may take pla… more
Date: July 1, 1979
Creator: Randrup, J.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Fully implicit three-dimensional MHD (magnetohydrodynamics) stability and evolution in toroidal geometry

Description: The FAR family of computer codes has been developed at Oak Ridge National Laboratory to solve ideal and resistive, linear and nonlinear, 3-D full MHD problems in toroidal geometry. Extensive application of an incompressible version of these codes has been made to the linear stability of tokamaks and stellarators, and nonlinear studies have also been recently completed. Present work includes generalization of the physical model in several respects to incorporate the effects of compressibility, l… more
Date: January 1, 1987
Creator: Holmes, J. A.; Charlton, L. A.; Carreras, B. A. & Lynch, V. E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ionization By Impact Electrons in Solids: Electron Mean Free Path Fitted Over A Wide Energy Range

Description: We propose a simple formula for fitting the electron mean free paths in solids both at high and at low electron energies. The free-electron-gas approximation used for predicting electron mean free paths is no longer valid at low energies (E < 50 eV), as the band structure effects become significant at those energies. Therefore we include the results of the band structure calculations in our fit. Finally, we apply the fit to 9 elements and 2 compounds.
Date: June 9, 2005
Creator: Ziaja, B; London, R A & Hajdu, J
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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In-situ X-ray photoelectron spectroscopy studies of water on metals and oxides at ambient conditions

Description: X-ray photoelectron spectroscopy (XPS) is a powerful tool for surface and interface analysis, providing the elemental composition of surfaces and the local chemical environment of adsorbed species. Conventional XPS experiments have been limited to ultrahigh vacuum (UHV) conditions due to a short mean free path of electrons in a gas phase. The recent advances in instrumentation coupled with third-generation synchrotron radiation sources enables in-situ XPS measurements at pressures above 5 Torr.… more
Date: October 29, 2007
Creator: Salmeron, Miquel; Yamamoto, S.; Bluhm, H.; Andersson, K.; Ketteler, G.; Ogasawara, H. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Simulation Strategies for Shock-Turbulence Interactions

Description: The computational challenge of predicting shock-turbulence interactions stems from the fundamentally different physics at play. Shock waves are microscopically thin regions wherein flow properties change rapidly over a distance roughly equal to the molecular mean free path; hence, they are essentially strong discontinuities in the flow field. Turbulence, on the other hand, is a chaotic phenomenon with broadband spatial and temporal scales of motion. Most shock-capturing methods rely on strong n… more
Date: February 20, 2008
Creator: Cook, A; Larsson, J; Cabot, W & Lele, S K
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Metal-insulator transition by isovalent anion substitution in Ga1-xMnxAs: Implications to ferromagnetism

Description: We have investigated the effect of partial isovalent anion substitution in Ga1-xMnxAs on electrical transport and ferromagnetism. Substitution of only 2.4percent of As by P induces a metal-insulator transition at a constant Mn doping of x=0.046 while the replacement of 0.4 percent As with N results in the crossover from metal to insulator for x=0.037. This remarkable behavior is consistent with a scenario in which holes located within an impurity band are scattered by alloy disorder in the anio… more
Date: February 7, 2008
Creator: Stone, P. R.; Alberi, K.; Tardif, S. K. Z.; Beeman, J. W.; Yu, K. M.; Walukiewicz, W. et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Aerial Neutron Detection of Cosmic-Ray Interactions with the Earth's Surface

Description: We have demonstrated the ability to measure the neutron flux produced by the cosmic-ray interaction with nuclei in the ground surface using aerial neutron detection. High energy cosmic-rays (primarily muons with GeV energies) interact with the nuclei in the ground surface and produce energetic neutrons via spallation. At the air-surface interface, the neutrons produced by spallation will either scatter within the surface material, become thermalized and reabsorbed, or be emitted into the air. T… more
Date: September 18, 2008
Creator: Maurer, Richard
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Ambient pressure photoelectron spectroscopy: a new tool for surface science and nanotechnology

Description: Progress in science often follows or parallels the development of new techniques. The optical microscope helped convert medicine and biology from a speculative activity in old times to today's sophisticated scientific disciplines. The telescope changed the study and interpretation of heavens from mythology to science. X-ray diffraction enabled the flourishing of solid state physics and materials science. The technique object of this review, Ambient Pressure Photoelectron Spectroscopy or APPES f… more
Date: March 12, 2008
Creator: Salmeron, Miquel; Salmeron, Miquel & Schlogl, Robert
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calculation of the Thermal Footprint of Resonant Magnetic Perturbations in DIII-D

Description: The effect of resonant magnetic perturbations on heat transport in DIII-D H-mode plasmas has been calculated by combining the TRIP3D field-line tracing code with the E3D two-fluid transport code. Simulations show that the divertor heat flux distribution becomes non-axisymmetric because heat flux is efficiently guided to the divertor along the three-dimensional invariant manifolds of the magnetic field. Calculations demonstrate that heat flux is spread over a wider area of the divertor target, t… more
Date: September 14, 2007
Creator: Joseph, I; Evans, T; Moyer, R; Fenstermacher, M; Groth, M; Kasilov, S et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Inelastic Neutron Cross Sections on Nuclei at FNAL

Description: Direct experimental measurements of the inelastic cross sections of neutrons on a variety of nuclei have been made at Fermi lab over the energy range from 50 to 350 GeV. These data may be used, together with nucleon-nucleon total cross sections measured through the same energy range, to justify and verify the interpretation of cosmic ray data on interaction mean free paths in air or iron in terms of nucleon-nucleon total cross sections at much higher energies.
Date: May 1, 1977
Creator: Jones, L. W.; Gustafson, H. R.; Longo, M. J.; Roberts, T. & Whalley, M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Mean free paths, viscosity, and the limitations of perfect fluid hydrodynamics in the description of the quark-gluon plasma

Description: The author discusses the applicability of a hydrodynamic description of high energy hadronic collisions. The author reviews the results of recent computations of the mean free paths of quarks and gluons in a quark-gluon plasma, and the corresponding results for viscous coefficients. These quantities are employed to evaluate the limits to the application of perfect fluid hydrodynamics as a description of time evolution of matter produced in various hadronic collisions. 22 references.
Date: November 1, 1984
Creator: McLerran, L.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Finite mean-free-path effects on axial particle transport in mirror devices

Description: The problem of collisional particle and energy transport in open-ended systems, where the axial transport is dominant, is considered. The Fokker-Planck equation for the distribution function has previously been solved in two limits: when the mean-free-path lambda/sub mfp/ is long compared to the system length L, and when lambda/sub mfp/ << L. A Monte Carlo procedure is presented for the solution of the equation which is formally valid for any range of lambda/sub mfp/L, although it is most pract… more
Date: June 8, 1979
Creator: Rognlien, T. D. & Cutler, T. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Inelastic Electron Scattering From Surfaces

Description: This report contains highlights of accomplishments of the past year, for the University of California, Irvine and the University of Wisconsin, Milwaukee collaboration on surface excitations, and their interactions with low energy electrons. In addition, we present a summary of future research to be carried out in the coming grant year.
Date: January 1, 1991
Creator: Tong, S. Y. & Mills, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Scattering of an ICRF magnetosonic wave by plasma density turbulence

Description: A fast ICRF magnetosonic wave, launched into a tokamak plasma, scatters off turbulent density fluctuations in the plasma edge. We use cold-fluid theory to calculate the angular distribution of the scattered wave and find it to be predominantly perpendicular to the incident wavevector for second harmonic majority heating. We calculate the mean free path and find it to be large compared to the size of tokamak devices. Therefore, scattering of ICRF magnetosonic waves by density turbulence is an ut… more
Date: April 1, 1989
Creator: Cook, D. R. & Kaufman, A. N.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Statistical properties of Lorentz lattice gases

Description: In this paper we present new results for the long-time tails and mean-square displacement evolution for several deterministic and probabilistic models of the Lorentz gas in a square lattice. The simulations give diffusion coefficients which agree with analytical results from the corresponding Boltzmann equation. For long times, abnormal diffusion is observed for the deterministic models only. This is probably due to recurring trajectories. The velocity autocorrelation function shows exponents w… more
Date: January 1, 1986
Creator: Binder, P.M.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Inelastic Electron Scattering From Surfaces

Description: This report contains highlights of accomplishments of the past year, for the University of California, Irvine and the University of Wisconsin, Milwaukee collaboration on surface excitations, and their interactions with low energy electrons. In addition, we present a summary of future research to be carried out in the coming grant year.
Date: January 1, 1992
Creator: Tong, S. Y. & Mills, D. L.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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