128,373 research outputs found

    Nuclear systems for space power and propulsion

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    As exploration and utilization of space proceeds through the 1970s, 1980s, and beyond, spacecraft in earth orbit will become increasingly larger, spacecraft will travel deeper into space, and space activities will involve more complex operations. These trends require increasing amounts of energy for power and propulsion. The role to be played by nuclear energy is presented, including plans for deep space missions using radioisotope generators, the reactor power systems for earth orbiting stations and satellites, and the role of nuclear propulsion in space transportation

    A primal method for minimal cost flows with applications to the assignment and transportation problems Technical report no. 32

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    Method for minimal cost flow analysis with applications to assignment and transportation problem

    Structural and mechanical effects of interstitial sinks

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    Contribution of interstitial sinks to creep strength of niobium- and tantalum-based alloys determined by effect on activation energy for cree

    Planetary submillimeter spectroscopy

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    The aim is to develop a comprehensive observational and analytical program to study solar system physics and meterology by measuring molecular lines in the millimeter and submillimeter spectra of planets and comets. A primary objective is to conduct observations with new JPL and Caltech submillimeter receivers at the Caltech Submillimeter Observatory (CSO) on Mauna Kea, Hawaii. A secondary objective is to continue to monitor the time variable planetary phenomena (e.g., Jupiter and Uranus) at centimeter wavelength using the NASA antennas of the Deep Space Network (DSN)

    Hydrogen-oxygen electrolytic regenerative fuel cells, 1 August - 1 September 1966

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    Single cells with potassium titanate matrices for improved cycle life performance of hydrogen- oxygen regenerative fuel cell

    Theory of Raman scattering from Leggett's collective mode in a multiband superconductor: Application to MgB2_2

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    In 1966 Leggett used a two-band superconductor to show that a new collective mode could exist at low temperatures, corresponding to a counter-flow of the superconducting condensates in each band. Here, the theory of electronic Raman scattering in a superconductor by Klein and Dierker (1984) is extended to a multiband superconductor. Raman scattering creates particle/hole pairs. In the relevant A1gA_{1g}\ symmetry, the attraction that produces pairing necessarily couples excitations of superconducting pairs to these p/h excitations. In the Appendix it is shown that for zero wave vector transfer % q this coupling modifies the Raman response and makes the long-range Coulomb correction null. The 2-band result is applied to MgB2_{2} where this coupling activates Leggett's collective mode. His simple limiting case is obtained when the interband attractive potential is decreased to a value well below that given by LDA theory. The peak from Leggett's mode is studied as the potential is increased through the theoretical value: With realistic MgB2_{2}\ parameters, the peak broadens through decay into the continuum above the smaller (π\pi band) superconducting gap. Finite qq effects are also taken into account, yielding a Raman peak that agrees well in energy with the experimental result by Blumberg \textit{et el.} (2007). This approach is also applied to the q=0q=0, 2-band model of the Fe-pnictides considered by Chubukov \textit{et al.}(2009).Comment: 10 pages, 3 figures. To appear in Physical Review

    Antisymmetric magnetoresistance of the SrTiO3/LaAlO3 interface

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    The longitudinal resistance RxxR_{xx} of the SrTiO3/LaAlO3 interface with magnetic fields applied perpendicular to the interface has an antisymmetric term (namely, Rxx(H)Rxx(H)R_{xx}(H)\neq R_{xx}(-H)) which increases with decreasing temperature and increasing field. We argue that the origin of this phenomenon is a non-homogeneous Hall effect with clear contribution of an extraordinary Hall effect, suggesting the presence of non-uniform field-induced magnetization

    A psychoanalytic concept illustrated: Will, must, may, can — revisiting the survival function of primitive omnipotence

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    The author explores the linear thread connecting the theory of Freud and Klein, in terms of the central significance of the duality of the life and death instinct and the capacity of the ego to tolerate contact with internal and external reality. Theoretical questions raised by later authors, informed by clinical work with children who have suffered deprivation and trauma in infancy, are then considered. Theoretical ideas are illustrated with reference to observational material of a little boy who suffered deprivation and trauma in infancy. He was first observed in the middle of his first year of life while he was living in foster care, and then later at the age of two years and three months, when he had been living with his adoptive parents for more than a year
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