A study of hydrogen Lyman alpha radiation using the beam-foil excitation method.
Free excited H atom Lyman alpha radiation intensity study using beam-foil excitation method
Chupp, E. L.↗
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Mean lives of some doubly excited levels in lithium. I.
Excited levels in Li I produced by Li 7 ion passage through carbon foil, measuring excitation mean lives by beam foil technique
Artinson, I.↗
Portable vibration exciter
Gas-driven vibration exciter produces a sinusoidal excitation function controllable in frequency and in amplitude. It allows direct vibration testing of components under normal loads, removing the possibility of component damage due to high static pressure.
Beecher, L. C.↗
Rotational excitation of diatomic molecular systems. II - H2 /plus/
Hydrogen molecules rotational excitation cross sections by electron impact in adiabatic excitation, discussing polarization and distortion effects
Chang, E. S.↗
Peak structural response to nonstationary random excitations
Study establishes distribution function of peak response values, based on frequency interpretation. Excitations considered include impact loading on landing gears and aircraft gust loading. Because of relative severity of excitations, prediction of fatigue and maximum response characteristics is important part of task of structural analysis and design.
Shinozuka, M.↗
Dissociative excitation of vacuum ultraviolet emission features by electron impact on molecular gases. I - H2 and O2
Vacuum UV emission features dissociative excitation by electron impact on molecular hydrogen and oxygen, measuring excitation cross sections from threshold to 350 eV
Mumma, M. J.↗
Pulse excitation of bolometer bridges
Driving bolometer bridge by appropriately phased excitation pulses increases signal-to-noise ratio of bolometer sensor which operates on a chopped light beam. Method allows higher applied voltage than is possible by conventional ac or dc excitation.
Rusk, S. J.↗
The dynamic characteristics of a turbo-rotor simulator supported on gas-lubricated foil bearings. Part 1: Response to rotating imbalance and unidirectional excitation
A sixteen-inch rotor, weighing approximately twenty-one pounds, was supported by air-lubricated foil bearings. In physical size and in mass distribution, the rotor closely matched that of an experimental Brayton cycle turboalternator unit. The rotor was stable in both vertical horizontal attitudes at speeds up to 50,000 rpm. A detailed description of the experimental apparatus and of the foil bearing design are given. The paper contains data on response of the rotor to rotating imbalance, symmetric and asymmetric, and to excitation by means of a vibrator (shake table). It is concluded that the gas-lubricated foil bearing suspension is free from fractional frequency whirl and suffers no loss of load capacity when excited at frequency equal to half the rotational speed. In contrast to rigid gas bearings, the foil bearing imposes no stringent requirements with respect to dimensional tolerances, cleanliness, or limitations of journal motion within the narrow confines of bearing clearance.
Licht, L.↗
A model for the acoustic impedance of a perforated plate liner with multiple frequency excitation
A nonlinear resistance model is used in the one-dimensional equations of motion with an arbitrary exciting pressure function. The effects of high amplitude fluid motion, grazing flow, and spectral excitation can be studied together. Sample calculations of acoustic resistances are presented using a high amplitude discrete tone superimposed upon a simulated white noise spectrum. The tone amplitude is varied and its effect is shown both with and without a grazing flow velocity.
Rice, E. J.↗
Dissociative excitation of vacuum ultraviolet emission features by electron impact on molecular gases. 3: CO2
Vacuum ultraviolet multiplets of C I, C II, and O I were produced by electron impact of CO2. Absolute emission cross sections for these multiplets were measured from threshold to 350 eV. The electrostatically focussed electron gun used in this series of experiments is described in detail. The atomic multiplets which were produced by dissociative excitation of CO2 and the cross sections at 100 eV are given. The dependence of the excitation functions on electron energy shows that these multiplets are produced by electric-dipole-allowed transitions in CO2.
Mumma, M. J.↗
Dissociative excitation of vacuum ultraviolet emission features by electron impact on molecular gases. 3: CO2
Vacuum ultraviolet multiplets of C I, C II, and O I were produced by electron impact on CO2. Absolute emission cross sections for these multiplets were measured from threshold to 350 eV. The electrostatically focused electron gun used is described in detail. The atomic multiplets which were produced by dissociative excitation of CO2 and the cross sections at 100 eV are presented. The dependence of the excitation functions on electron energy shows that these multiplets are produced by electric-dipole-allowed transitions in CO2.
Mumma, M. J.↗
Measurement of relative cross sections for simultaneous ionization and excitation of the helium 4 2s and 4 2p states
The relative cross sections for simultaneous ionization and excitation of helium by 200-eV electrons into the 4 2s and 4 2p states were measured via a fast delayed coincidence technique. Results show good agreement with the relative cross sections for single electron excitation of helium and hydrogen. An application of the results of the measurement to the development of ultraviolet intensity standard is suggested. This technique involves the use of known branching ratios, a visible light flux reference, and the measured relative cross sections.
Sutton, J. F.↗
The excitation of vacuum ultraviolet radiation by electron impact on carbon monoxide: Some unresolved questions near threshold
The threshold behavior of the ultraviolet photon excitation function for electron impact on carbon monoxide was studied for the pseudo-resonance signal reported elsewhere. Time of flight spectrometer techniques were not able to confirm the resonant feature in excited CO states under electron impact.
Wells, W. C.↗
Study of excitation transfer in a flowing helium afterglow pumped with a tuneable dye laser. 1: Measurement of the rate coefficient for selected quenching reactions involving he(5 3P)
A system is described for the measurement of excited state reaction times in the nanosecond range. A flowing afterglow produces large populations of chemically unstable species, and a pulsed, tuneable dye laser is used to selectively pump these into the reacting excited state. The transient fluorescence from the populations of reactants and end products is used to determine reaction lifetimes and yields. This radiatron is collected with a photon counting system which logs arrival times of spectrally dispersed photons with 10 nanosecond resolution.
Collins, C. B.↗
The excitation of O2 in auroras
Newly measured electron impact cross sections for excitation of the a 1 Delta g and b 1 Sigma g+ electronic states of O2 were employed to predict the absolute volume emission rates from these states under auroral conditions. A secondary electron electron flux typical of an IBC II nighttime aurora was used and the most important quenching processes were included in the calculations. The new excitation cross sections for the a 1 Delta g and b 1 Sigma g+ states are more than an order of magnitude larger than previous estimates, and lead to correspondingly greater intensities in the atmospheric and IR-atmospheric band systems. The calculated intensity ratios of the volume emission rates of 7621 A and 1.27 microns to that for 3914 A are smaller than obtained from aircraft observations and recent rocket experiments.
Cartwright, D. C.↗
Application of the adiabatic-nuclei theory to vibrational excitation.
The adiabatic-nuclei theory is shown to be quantitatively applicable to vibrational excitation of diatomic molecules by electron impact. When the dependence of the fixed-nuclei phase shifts on internuclear separation is approximated by a two-term Taylor series, the resulting formulas are transparent and easily evaluated. Application to e-H2 excitation is made, phase-shift derivatives are estimated, and the theory is found to fit experimental data.
Faisal, F. H. M.↗
Effect of charge polarization on inelastic scattering - Differential and integral cross sections for excitation of the 2/super 1/S state of helium by electron impact.
Experimental differential scattering cross sections for excitation of helium by electron impact from its ground state to its 2(super 1)S state are presented at four incident electron energies in the range from 26 to 55.5 eV for scattering angles between 10 and 70 deg and at 81.6 eV for scattering angles between 10 and 80 deg. These cross sections are normalized and compared with results predicted by the Born approximation, the polarized Born approximation, and several other first-order approximations in which direct excitation is calculated in the Born approximation and exchange scattering in various Ochkur-like approximations.
Rice, J. K.↗
Vacuum-ultraviolet excitation cross sections by electron impact on NO.
Absolute excitation functions were measured for the NO(+) A l super Pi-Chi 1 super Sigma (+) molecular band system, the nitrogen 1200-, 1243-, and 1493-A multiplets, and oxygen 1304-A multiplet. Excitation was by electron impact on NO from threshold to approximately 250 eV. Results are plotted and tabulated.
Mentall, J. E.↗