4,256 research outputs found

    Simulation study of gust alleviation in a tilt rotor aircraft, volume 1

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    The response to vertical turbulence in cruise of the HTR XV-15 design is studied using simulation techniques. This design is a modified version of the XV-15 with a hingeless fiberglass soft-in-plane rotor system. The parameters of a gust alleviation system are determined and the performance of the system is evaluated over a range of cruise velocities and altitudes

    Study of an attitude reference system utilizing an electrically suspended gyro final report, 1 aug. 1964 - 31 mar. 1965

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    Miniature electrically suspended gyroscope for spacecraft attitude reference syste

    Comparison of optical model results from a microscopic Schr\"odinger approach to nucleon-nucleus elastic scattering with those from a global Dirac phenomenology

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    Comparisons are made between results of calculations for intermediate energy nucleon-nucleus scattering for 12C, 16O, 40Ca, 90Zr, and 208Pb, using optical potentials obtained from global Dirac phenomenology and from a microscopic Schr\"odinger model. Differential cross sections and spin observables for scattering from the set of five nuclei at 65 MeV and 200 MeV have been studied to assess the relative merits of each approach. Total reaction cross sections from proton-nucleus and total cross sections from neutron-nucleus scattering have been evaluated and compared with data for those five targets in the energy range 20 MeV to 800 MeV. The methods of analyses give results that compare well with experimental data in those energy regimes for which the procedures are suited.Comment: 22 pages, 12 figure

    Determination of the structure of 31^{31}Ne by full-microscopic framework

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    We perform the first quantitative analysis of the reaction cross sections of 28−32^{28-32}Ne by 12^{12}C at 240 MeV/nucleon, using the double-folding model (DFM) with the Melbourne gg-matrix and the deformed projectile density calculated by the antisymmetrized molecular dynamics (AMD). To describe the tail of the last neutron of 31^{31}Ne, we adopt the resonating group method (RGM) combined with AMD. The theoretical prediction excellently reproduce the measured cross sections of 28−32^{28-32}Ne with no adjustable parameters. The ground state properties of 31^{31}Ne, i.e., strong deformation and a halo structure with spin-parity 3/2−3/2_{}^-, are clarified.Comment: 4 pages, 4 figures, 2 table

    Deformation effect on total reaction cross sections for neutron-rich Ne-isotopes

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    Isotope-dependence of measured reaction cross sections in scattering of 28−32^{28-32}Ne isotopes from 12^{12}C target at 240 MeV/nucleon is analyzed by the double-folding model with the Melbourne gg-matrix. The density of projectile is calculated by the mean-field model with the deformed Wood-Saxon potential. The deformation is evaluated by the antisymmetrized molecular dynamics. The deformation of projectile enhances calculated reaction cross sections to the measured values.Comment: 6 pages, 4 figures, 2 table

    Trends and Variation in End-of-Life Care for Medicare Beneficiaries With Severe Chronic Illness

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    Provides an updated analysis of regional and hospital variations in end-of-life care for Medicare beneficiaries with chronic illnesses, including percentage of hospital deaths, days in intensive care units, and physician labor per patient

    Nucleon-nucleus optical potential in the particle-hole approach

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    Feshbach's projection formalism in the particle-hole model space leads to a microscopic description of scattering in terms of the many-body self-energy. To investigate the feasibility of this approach, an optical potential for O-16 is constructed starting from two previous calculations of the self-energy for this nucleus. The results reproduce the background phase shifts for positive parity waves and the resonances beyond the mean field. The latter can be computed microscopically for energies of astrophysical interest using Green's function theory.Comment: 8 pages, 6 figures. Submitted to Phys. Rev.
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