141,478 research outputs found

    Future spaceborne memories with 10 sup 3- 10 sup 7 bit capacities

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    Weight, volume, and power estimates of future spaceborne memories with small bit capacitie

    Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 7Li+208Pb System at Near-Coulomb-Barrier Energies using the Folding Potential

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    Simultaneous χ2\chi^{2} analyses previously made for elastic scattering and fusion cross section data for the 6^{6}Li+208^{208}Pb system is extended to the 7^{7}Li+208^{208}Pb system at near-Coulomb-barrier energies based on the extended optical model approach, in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and that both the DR and fusion parts of the polarization potential determined from the χ2\chi^{2} analyses satisfy separately the dispersion relation. Further, we find that the real part of the fusion portion of the polarization potential is attractive while that of the DR part is repulsive except at energies far below the Coulomb barrier energy. A comparison is made of the present results with those obtained from the Continuum Discretized Coupled Channel (CDCC) calculations and a previous study based on the conventional optical model with a double folding potential. We also compare the present results for the 7^7Li+208^{208}Pb system with the analysis previously made for the 6^{6}Li+208^{208}Pb system.Comment: 7 figures, submitted to PR

    Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Section Data for the 12^{12}C+208^{208}Pb System at Near-Coulomb-Barrier Energies by using a Folding Potential

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    Simultaneous χ2\chi^{2} analyses are performed for elastic scattering and fusion cross section data for the 12^{12}C+208^{208}Pb system at near-Coulomb-barrier energies by using the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts. Use is made of the double folding potential as a bare potential. It is found that the experimental elastic scattering and fusion data are well reproduced without introducing any normalization factor for the double folding potential and also that both DR and fusion parts of the polarization potential determined from the χ2\chi^{2} analyses satisfy separately the dispersion relation. Furthermore, it is shown that the imaginary parts of both DR and fusion potentials at the strong absorption radius change very rapidly, which results in a typical threshold anomaly in the total imaginary potential as observed with tightly bound projectiles such as α\alpha-particle and 16^{16}O.Comment: 26 pages, 7 figures, submitted to Physical Review

    Extended Optical Model Analyses of Elastic Scattering and Fusion Cross Sections for 6Li + 208Pb System at Near-Coulomb-Barrier Energies by using Folding Potential

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    Based on the extended optical model approach in which the polarization potential is decomposed into direct reaction (DR) and fusion parts, simultaneous χ2\chi^{2} analyses are performed for elastic scattering and fusion cross section data for the 6^{6}Li+208^{208}Pb system at near-Coulomb-barrier energies. A folding potential is used as the bare potential. It is found that the real part of the resultant DR part of the polarization potential is repulsive, which is consistent with the results from the Continuum Discretized Coupled Channel (CDCC) calculations and the normalization factors needed for the folding potentials. Further, it is found that both DR and fusion parts of the polarization potential satisfy separately the dispersion relation.Comment: 6 figure

    Parametric resonance for antineutrino conversions using LSND best-fit results with a 3+1 flavor scheme

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    An analytical solution to a parametric resonance effect for antineutrinos in a 3+1 flavor (active+sterile) scheme using multiple non-adiabatic density shifts is presented. We derive the conditions for a full flavor conversion for antineutrino oscillations νˉα→νˉs\bar{\nu}_\alpha \to \bar{\nu}_s (α=e,μ,τ)(\alpha=e,\mu,\tau) under the assumption that LSND best-fits for the mixing parameters are valid in a short-baseline accelerator experiment. We show that the parametric resonance effect can be exploited to increase the effective antineutrino oscillation length by a factor of 10-40, thus sustaining a high oscillation probability for a much longer period of time than in the vacuum scenario. We propose a realistic experimental setup that could probe for this effect which leaves a signature in terms of a specific oscillation probability profile. Moreover, since the parametric resonance effect is valid in any 2 or 1+1 flavor approximation, our results could be suggestive for future short-baseline accelerator neutrino detection experiments.Comment: 6 pages, 4 figure

    Inverse Modelling to Obtain Head Movement Controller Signal

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    Experimentally obtained dynamics of time-optimal, horizontal head rotations have previously been simulated by a sixth order, nonlinear model driven by rectangular control signals. Electromyography (EMG) recordings have spects which differ in detail from the theoretical rectangular pulsed control signal. Control signals for time-optimal as well as sub-optimal horizontal head rotations were obtained by means of an inverse modelling procedures. With experimentally measured dynamical data serving as the input, this procedure inverts the model to produce the neurological control signals driving muscles and plant. The relationships between these controller signals, and EMG records should contribute to the understanding of the neurological control of movements

    Magnetic Order and Spin Dynamics in Ferroelectric HoMnO3_{3}

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    Hexagonal HoMnO3_{3} is a frustrated antiferromagnet (TN_{N}=72 K) ferroelectric (TC_{C}=875 K) in which these two order parameters are coupled. Our neutron measurements of the spin wave dispersion for the S=2 Mn3+^{3+} on the layered triangular lattice are well described by a two-dimensional nearest-neighbor Heisenberg exchange J=2.44 meV, and an anisotropy DD that is 0.093 meV above the spin reorientation transition at 40 K, and 0.126 meV below. For H∥cH\parallel c the magnetic structures and phase diagram have been determined, and reveal additional transitions below 8 K where the ferroelectrically displaced Ho3+^{3+} ions are ordered magnetically.Comment: To be published in Physical Review Letter

    Strain-mediated metal-insulator transition in epitaxial ultra-thin films of NdNiO3

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    We have synthesized epitaxial NdNiO3_{3} ultra-thin films in a layer-by-layer growth mode under tensile and compressive strain on SrTiO3_{3} (001) and LaAlO3_3 (001), respectively. A combination of X-ray diffraction, temperature dependent resistivity, and soft X-ray absorption spectroscopy has been applied to elucidate electronic and structural properties of the samples. In contrast to the bulk NdNiO3_{3}, the metal-insulator transition under compressive strain is found to be completely quenched, while the transition remains under the tensile strain albeit modified from the bulk behavior.Comment: 4 pages, 4 figure
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