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Full-Text Articles in Physics
Energy Dependence Of Amorphizing Implant Dose In Silicon, John R. Dennis, Edward Boyd Hale
Energy Dependence Of Amorphizing Implant Dose In Silicon, John R. Dennis, Edward Boyd Hale
Physics Faculty Research & Creative Works
The radiation-induced transformation from crystalline to amorphous silicon was studied using ion implantation. The ion energy was varied from 20 to 180 keV for Li+, N+, Ne+, Ar+, and Kr +. The energy dependence of the critical amorphizing dose was determined by electron spin resonance. Comparison of the data with theoretical calculations of the energy density deposited into atomic processes showed good agreement. This energy-dependent agreement gave evidence that energy density is important to the transformation at both low and high implantation temperatures.
Excitation Of The N=2 State Of Atomic Hydrogen By Electron Impact In The Distorted-Wave Approximation, Ralph V. Calhoun, Don H. Madison, W. Neil Shelton
Excitation Of The N=2 State Of Atomic Hydrogen By Electron Impact In The Distorted-Wave Approximation, Ralph V. Calhoun, Don H. Madison, W. Neil Shelton
Physics Faculty Research & Creative Works
The differential cross sections for excitation of the n=2 state of atomic hydrogen by the impact of electrons with energies of 54, 100, 136, and 200 eV are calculated in the distorted-wave approximation with exchange included. Cross sections for excitation of the 2s1/2, 2p1/2, and 2p3/2 states are calculated and summed to give the n=2 differential cross sections. The results of this calculation are compared with previous theoretical calculations and with recent absolute experimental data.
Cross Sections For Excitation Of Atomic Hydrogen To The N=2, 3, And 4 States By 15-200-Kev Protons, John T. Park, Judith E. Aldag, Jacob M. George, Jerry Peacher
Cross Sections For Excitation Of Atomic Hydrogen To The N=2, 3, And 4 States By 15-200-Kev Protons, John T. Park, Judith E. Aldag, Jacob M. George, Jerry Peacher
Physics Faculty Research & Creative Works
Cross sections for the processes H++H(1 s)H++H*(n = 2, 3, 4) have been extracted from the energy-loss spectra of 15- to 200-keV protons by using a spectrum-fitting technique. Absolute cross sections have been obtained by normalization of the spectra to the theoretical cross section through the use of the Born approximation at 200 keV. The cross-section curves are very similar in shape with maxima at 60 keV. The results have been compared with available theoretical calculations. The n = 2 and n = 3 cross-section measurements are in very good agreement in curve shape with Glauber-approximation …
Comparison Of Experimental And Theoretical Electron Ejection Cross Sections In Helium By Proton Impact From 5 To 100 Kev, M. Eugene Rudd, Don H. Madison
Comparison Of Experimental And Theoretical Electron Ejection Cross Sections In Helium By Proton Impact From 5 To 100 Kev, M. Eugene Rudd, Don H. Madison
Physics Faculty Research & Creative Works
Absolute values of doubly differential cross sections are obtained for electron production in helium by 5- to 100-keV proton impact. The measured values along with earlier data at higher energies are compared with theoretical plane-wave Born-approximation functions obtained from a Hartree-Fock potential. Not only is good agreement obtained at high impact energies (above 300 keV), but fairly good agreement is found at low energies (below about 20 keV). For electrons ejected in the backward hemisphere, unexpectedly poor agreement is noted at intermediate energies where the measured cross sections dip to 50% of the calculated values in some cases. Singly differential …
Intermetallic Reactions In Vacuum-Deposited Nickel And Gold Films On (111) Silicon Single Crystals, K. H. Yoon, Gordon Lewis, L. L. Levenson
Intermetallic Reactions In Vacuum-Deposited Nickel And Gold Films On (111) Silicon Single Crystals, K. H. Yoon, Gordon Lewis, L. L. Levenson
Materials Science and Engineering Faculty Research & Creative Works
Pure nickel and gold thin films were vacuum-deposited on (111) silicon single crystals. When Ni/Au/Si or Au/Ni/Si samples were heated to about 550° in situ, hexagonal or deformed hexagonal shaped crystallites were formed on the silicon substrates. The composition of these crystallites was determined by using x-ray diffraction, scanning electron microscopy and scanning Auger microprobe methods. The crystallites were identified as NiSi2. The crystal-lites on the (111) silicon plane parallel to the surface appeared as regular hexagons while the inclined crystal-lites resembled trapezia. The results of Auger spectra and in-depth composition profiles for Ni, Au, and Si showed that the …
Comment On "Clustering Of Water On Hydrated Protons In A Supersonic Free Jet Expansion", James L. Kassner, Donald E. Hagen
Comment On "Clustering Of Water On Hydrated Protons In A Supersonic Free Jet Expansion", James L. Kassner, Donald E. Hagen
Physics Faculty Research & Creative Works
No abstract provided.
The Martensite Transformation, Manfred Wuttig, Tetsuro Suzuki
The Martensite Transformation, Manfred Wuttig, Tetsuro Suzuki
Materials Science and Engineering Faculty Research & Creative Works
No abstract provided.
Absorption In The Infrared Of Surface Electromagnetic Waves By Adsorbed Molecules On A Copper Surface, K. Bhasin, D. Bryan, Ralph William Alexander, Robert John Bell
Absorption In The Infrared Of Surface Electromagnetic Waves By Adsorbed Molecules On A Copper Surface, K. Bhasin, D. Bryan, Ralph William Alexander, Robert John Bell
Physics Faculty Research & Creative Works
Experimental Observations Have Been Made for the First Time that Surface Electromagnetic Wave (SEW) Spectroscopy Can Be Used to Measure the Infrared Spectra of Adsorbed Molecules and Very Thin Films on Metal Surfaces. using a Tunable CO2 Laser (9.2-10.8 Μm Wavelength), the 975 and the 1037 Cm-1 Resonances of 5-25 Å Thick Physiosorbed Benzene on Copper Were Observed. Broadening of These Resonances for the Thinnest Layers of Benzene Was Observed. Also SEW Spectroscopy and Ellipsometry Were Used to Study Thin Films of Cellulose Acetate (15-75 Å) on Copper. Further, It Was Shown that Film Thicknesses Determined by SEW Spectroscopy Are …
Thomson's Monopoles, I. Adawi
Thomson's Monopoles, I. Adawi
Physics Faculty Research & Creative Works
The angular momentum L of the electromagnetic field due to an electric point charge e, and a magnetic point charge (pole) g, is calculated by several methods to obtain J. J. Thomson's result that L = eg/c, and L is directed along the line joining the electric monopole to the magnetic monopole. The relation to Dirac's monopoles is discussed, and particle size is considered. © 1991, American Association of Physics Teachers. All rights reserved.
Radiative Lifetimes And Alignment Depolarization Cross Sections For Ybi And Ii By The Hanle Effect In A Flowing Helium System, F. H.K. Rambow, Laird D. Schearer
Radiative Lifetimes And Alignment Depolarization Cross Sections For Ybi And Ii By The Hanle Effect In A Flowing Helium System, F. H.K. Rambow, Laird D. Schearer
Physics Faculty Research & Creative Works
The radiative lifetimes of the 17992-,25068-,28857-, 37414-, 40564-, and 44017-cm-1 neutral levels and the 30392-cm-1 ion level of Yb have been measured by the Hanle method in a fast-flowing He system. The lifetimes (in units of 10-9 sec) were found to be 820(20), 5.12(0.12), 14.4(0.4), 77.4(6.0), 9.32(0.6), 39.1(3.5), and 5.8(0.6), respectively. In a flowing system with He as a buffer gas the alignment depolarization cross sections with Yb were obtained and are reported here for the first time. They are (in units of 10-15 cm2) 5.0(1.0), 5.9(1.0), 5.9(1.2), 17.9(2.0), 28.2(3.0), 5.16(4.0), and 7.2(2.5), respectively. © 1976 The American Physical Society.
Numerical Simulation Of A Widely Used Cloud Nucleus Counter., Darryl J. Alofs, J. C. Carstens
Numerical Simulation Of A Widely Used Cloud Nucleus Counter., Darryl J. Alofs, J. C. Carstens
Mechanical and Aerospace Engineering Faculty Research & Creative Works
The Performance of the Conventional Horizontal Plate Thermal Diffusion Chamber as a Cloud Nucleus Counter Was Studied. Numerical Calculations Were Performed in Order to Follow the Simultaneous Drop Growth and Sedimentation in the Spatially and Temporally Nonuniform Supersaturation Field. the Effect of Nuclei Distribution and Smallest Detectable Drop Size Were Investigated. the Results Indicate Order of Magnitude Uncertainty in the Count at 0. 1% Supersaturation, and a Factor of 2 Uncertainty at 1. 0% Supersaturation.
Surface Electromagnetic Waves With Damping. I. Isotropic Media, G. S. Kovener, Ralph William Alexander, Robert John Bell
Surface Electromagnetic Waves With Damping. I. Isotropic Media, G. S. Kovener, Ralph William Alexander, Robert John Bell
Physics Faculty Research & Creative Works
Surface-Electromagnetic-Wave Dispersion Curves Are Usually Calculated using a Simple Equation Derived from Maxwell's Equations and Boundary Conditions. When Complex Dielectric Functions Are Used for the Two Media, the Component of the Propagation Vector Along the Surface, Kx, Becomes Infinite as the Frequency Approaches the Surface Polariton Frequency Ωs If Ω is Considered Complex and Kx is Real. on the Other Hand, If Kx is Considered Complex and Ω Real, the Dispersion Curves Bend Back Toward Smaller Kx as Ω Approaches Ωs. We Have Previously Demonstrated that Both Types of Behavior Can Be Obtained from Attenuated-Total-Reflection Measurements of Silver. We Now …
Surface Electromagnetic Wave Mode And Field Analysis In A Metal-Metal-Oxide-Air System With Damping, C. A. Ward, Ralph William Alexander, Robert John Bell
Surface Electromagnetic Wave Mode And Field Analysis In A Metal-Metal-Oxide-Air System With Damping, C. A. Ward, Ralph William Alexander, Robert John Bell
Physics Faculty Research & Creative Works
An Explanation is Provided for the Surface Electromagnetic Wave (SEW) Energy Ejection from a Thin Film at the Longitudinal and Transverse Optical-Phonon Frequencies of the Film Material. Field Ratio Calculations Identify Previously Discussed Metal-Metal-Oxide-Air SEW Modes as Those Expected from the Berreman Configuration, and It is Shown that Greenler Technique High-Incidence-Angle-Reflectance Data on the Same System May Be Similarly Interpreted. © 1976 the American Physical Society.
The Magnification Factor For Sodium Chloride Liesegang Circles Established With An Aerosol Centrifuge, O. Preining, Josef Podzimek, P. Yue
The Magnification Factor For Sodium Chloride Liesegang Circles Established With An Aerosol Centrifuge, O. Preining, Josef Podzimek, P. Yue
Physics Faculty Research & Creative Works
Sodium chloride particles deposited on a gelatin film containing silver nitrate form in a humid environment clearly visible dark brown reaction spots (Liesegang circles) after development in u.v.-light. The size of these reaction spots depends on the mass of NaCl in the particles. To establish the spot size vs particle size relation, particles produced by nebulising NaCl-solutions and sea water were sampled in an aerosol centrifuge. The location of deposition yields the aerodynamic diameter of the particle, and the spot size is measured microscopically. In this way the spot size vs aerodynamic diameter relation is established experimentally in the so …
Note On Amorphous Magnetic Materials, Louis H. Lund
Note On Amorphous Magnetic Materials, Louis H. Lund
Physics Faculty Research & Creative Works
No abstract provided.
Radiative Lifetimes Of Some Group Ii Ions By The Hanle Effect In A Fast-Flowing Helium Afterglow, F. H.K. Rambow, Laird D. Schearer
Radiative Lifetimes Of Some Group Ii Ions By The Hanle Effect In A Fast-Flowing Helium Afterglow, F. H.K. Rambow, Laird D. Schearer
Physics Faculty Research & Creative Works
Radiative lifetimes of the first P322 state of Mgu, Cau, Znu, Sru, Cdu, and Bau are reported as measured by the Hanle effect in a fast-flowing helium afterglow. They are, respectively, 3.65(0.12), 6.61(0.30), 2.4(0.3), 6.64(0.10), 2.86(0.25), 6.78(0.40) in units of 10-9 sec. The ions in the afterglow are created by Penning ionization of the neutral metal atoms, thus providing a steady-state, field-free region for observation. Comparisons are made with measurements by other methods, and discrepancies are discussed. © 1976 The American Physical Society.