55,282 research outputs found

    Spectral bounds for the cutoff Coulomb potential

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    The method of potential envelopes is used to analyse the bound-state spectrum of the Schroedinger Hamiltonian H = -Delta -v/(r+b), where v and b are positive. We established simple formulas yielding upper and lower energy bounds for all the energy eigenvalues.Comment: 11 pages, 2 figure

    Devonian Sandstone Lithostratigraphy, Northern Arkansas

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    Two areas of Devonian sandstone development may be recognized in northern Arkansas. In northwestern Arkansas, the Clifty Formation comprises a massively bedded, super mature quartz arenite of Middle Devonian age overlain by thinner bedded, phosphatic quartz arenite and chert breccia of the Sylamore Sandstone Member, Chattanooga Shale (Upper Devonian). This sequence overlies Ordovician strata (Powell or Everton) and is succeeded by the Chattanooga Shale and strata of Lower Mississippian age. In north-central Arkansas, the Clifty Formation is absent and the Chattanooga Shale may develop sandstone at its base and top. Occasionally the Chattanooga Shale is absent and the entire interval may be Upper Devonian sandstone. These Upper Devonian sandstones are phosphatic, mature quartz arenites referred to the Sylamore Member except where they overlie the Chattanooga Shale. In these cases, the sandstone is recognized as an informal upper member of the Chattanooga. Reports of Lower Mississippian Sylamore Sandstone in north-central Arkansas are regarded as misidentification of the Bachelor Formation (Middle Kinderhookian

    Coulomb plus power-law potentials in quantum mechanics

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    We study the discrete spectrum of the Hamiltonian H = -Delta + V(r) for the Coulomb plus power-law potential V(r)=-1/r+ beta sgn(q)r^q, where beta > 0, q > -2 and q \ne 0. We show by envelope theory that the discrete eigenvalues E_{n\ell} of H may be approximated by the semiclassical expression E_{n\ell}(q) \approx min_{r>0}\{1/r^2-1/(mu r)+ sgn(q) beta(nu r)^q}. Values of mu and nu are prescribed which yield upper and lower bounds. Accurate upper bounds are also obtained by use of a trial function of the form, psi(r)= r^{\ell+1}e^{-(xr)^{q}}. We give detailed results for V(r) = -1/r + beta r^q, q = 0.5, 1, 2 for n=1, \ell=0,1,2, along with comparison eigenvalues found by direct numerical methods.Comment: 11 pages, 3 figure

    Eigenvalue bounds for a class of singular potentials in N dimensions

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    The eigenvalue bounds obtained earlier [J. Phys. A: Math. Gen. 31 (1998) 963] for smooth transformations of the form V(x) = g(x^2) + f(1/x^2) are extended to N-dimensions. In particular a simple formula is derived which bounds the eigenvalues for the spiked harmonic oscillator potential V(x) = x^2 + lambda/x^alpha, alpha > 0, lambda > 0, and is valid for all discrete eigenvalues, arbitrary angular momentum ell, and spatial dimension N.Comment: 10 pages (plain tex with 2 ps figures). J.Phys.A:Math.Gen.(In Press

    Air motion determination by tracking humidity patterns in isentropic layers

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    Determining air motions by tracking humidity patterns in isentropic layers was investigated. Upper-air rawinsonde data from the NSSL network and from the AVE-II pilot experiment were used to simulate temperature and humidity profile data that will eventually be available from geosynchronous satellites. Polynomial surfaces that move with time were fitted to the mixing-ratio values of the different isentropic layers. The velocity components of the polynomial surfaces are part of the coefficients that are determined in order to give an optimum fitting of the data. In the mid-troposphere, the derived humidity motions were in good agreement with the winds measured by rawinsondes so long as there were few or no clouds and the lapse rate was relatively stable. In the lower troposphere, the humidity motions were unreliable primarily because of nonadiabatic processes and unstable lapse rates. In the upper troposphere, the humidity amounts were too low to be measured with sufficient accuracy to give reliable results. However, it appears that humidity motions could be used to provide mid-tropospheric wind data over large regions of the globe

    Design, development and fabrication of a Precision Autocollimating Solar Sensor /PASS/

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    Precision Autocollimating Solar Sensor /PASS/ for Solar Pointing Aerobee Rocket Control System /SPARCS/ progra

    Carbon Dioxide Observational Platform System (CO-OPS), feasibility study

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    The Carbon Dioxide Observational Platform System (CO-OPS) is a near-space, geostationary, multi-user, unmanned microwave powered monitoring platform system. This systems engineering feasibility study addressed identified existing requirements such as: carbon dioxide observational data requirements, communications requirements, and eye-in-the-sky requirements of other groups like the Defense Department, the Forestry Service, and the Coast Guard. In addition, potential applications in: earth system science, space system sciences, and test and verification (satellite sensors and data management techniques) were considered. The eleven month effort is summarized. Past work and methods of gathering the required observational data were assessed and rough-order-of magnitude cost estimates have shown the CO-OPS system to be most cost effective (less than $30 million within a 10 year lifetime). It was also concluded that there are no technical, schedule, or obstacles that would prevent achieving the objectives of the total 5-year CO-OPS program

    Study of behavioral modifications resulting from exposure to high let radiation

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    Animal irradiations, behavioral studies, neurological studies, and nuclear medicine studies are discussed
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