1,139 research outputs found

    Development of protective coatings for tantalum T-22 alloy Final summary report

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    Oxidation resistance tests of protective coatings for tantalum allo

    Electrophoretic deposition of gradated oxidation resistant coatings on tantalum-10 tungsten alloy

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    Material selection and electrophoretic deposition studies of high temperature oxidation resistant coatings on tantalum-10 tungsten allo

    Development of oxidation resistant coatings for use above 3500 deg F

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    Physical property evaluation of oxidation resistant coating materials for high temperature protection of tantalum-base alloy

    Can a Postmodern Philosopher Teach Modern Philosophy?

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    This paper considers the following question: how can those whose thought is informed by poststructuralist values, arguments, and training legitimately teach the history of philosophy? In answering this question, three pedagogical approaches to courses in the history of philosophy are considered and criticized: the representational, the phenomenological, and the conversational. Although these three approaches are seemingly exhaustive, each is problematic because the question they attempt to answer rests on the false assumption that there is one, universally right way to teach philosophy and many wrong ways. In rejecting this assumption, the author considers a new, more concrete, and contextualized question concerning teaching philosophy from a postmodern perspective

    Relativistic photoelectron spectra in the ionization of atoms by elliptically polarized light

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    Relativistic tunnel ionization of atoms by intense, elliptically polarized light is considered. The relativistic version of the Landau-Dykhne formula is employed. The general analytical expression is obtained for the relativistic photoelectron spectra. The most probable angle of electron emission, the angular distribution near this angle, the position of the maximum and the width of the energy spectrum are calculated. In the weak field limit we obtain the familiar non-relativistic results. For the case of circular polarization our analytical results are in agreement with recent derivations of Krainov [V.P. Krainov, J. Phys. B, {\bf 32}, 1607 (1999)].Comment: 8 pages, 2 figures, accepted for publication in Journal of Physics

    The Nonlinear Debye-Onsager Relaxation Effect in Weakly Ionized Plasmas

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    A weakly ionized plasma under the influence of a strong electric field is considered. Supposing a local Maxwellian distribution for the electron momenta the plasma is described by hydrodynamic equations for the pair distribution functions. These equations are solved and the relaxation field is calculated for an arbitrary field strength. It is found that the relaxation effect becomes lower with increasing strength of the electrical field.Comment: 4 pages, 1 figur

    Optimization and evaluation of electrophoretic protective coatings for tantalum T-222 alloy Final summary report, 1 Jul. 1966 - 27 Oct. 1967

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    Protective coating parameters for improving oxidation resistance and reliability of silicide coating systems for tantalum alloy

    Reply to \u27Do oceanic zooplankton aggregate at, or near, the deep chlorophyll maximum?\u27

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    We appreciate the time and attention given our paper by Longhurst and Herman and the opportunity to reply to their critique. Unfortunately, we believe their difficulties with the presentation of our data are more subjective than substantive. In fact, we believe a careful reading of our text will show that our conclusions are suitably conservative...

    An Analysis of Surface Relaxation in the Surface Cauchy--Born Model

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    The Surface Cauchy-Born (SCB) method is a computational multi-scale method for the simulation of surface-dominated crystalline materials. We present an error analysis of the SCB method, focused on the role of surface relaxation. In a linearized 1D model we show that the error committed by the SCB method is O(1) in the mesh size; however, we are able to identify an alternative "approximation parameter" - the stiffness of the interaction potential - with respect to which the error in the mean strain is exponentially small. Our analysis naturally suggests an improvement of the SCB model by enforcing atomistic mesh spacing in the normal direction at the free boundary

    Relativistic semiclassical approach in strong-field nonlinear photoionization

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    Nonlinear relativistic ionization phenomena induced by a strong laser radiation with elliptically polarization are considered. The starting point is the classical relativistic action for a free electron moving in the electromagnetic field created by a strong laser beam. The application of the relativistic action to the classical barrier-suppression ionization is briefly discussed. Further the relativistic version of the Landau-Dykhne formula is employed to consider the semiclassical sub-barrier ionization. Simple analytical expressions have been found for: (i) the rates of the strong-field nonlinear ionization including relativistic initial and final state effects; (ii) the most probable value of the components of the photoelectron final state momentum; (iii) the most probable direction of photoelectron emission and (iv) the distribution of the photoelectron momentum near its maximum value.Comment: 13 pages, 3 figures, to be published in Phys. Rev.
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