11,460 research outputs found

    Fast High Resolution Echelle Spectroscopy Of A Laboratory Plasma

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    An echelle diffraction grating and a multianode photomultiplier tube are paired to construct a high resolution (R=lambda/delta lambda approximate to 2.5x10(4)) spectrograph with fast time response for use from the UV through the visible. This instrument has analyzed the line shape of C III impurity ion emission at 229.687 nm over the lifetime (approximate to 100 mu s) of the hydrogen plasmas produced at SSX. The ion temperature and line of sight average velocity are inferred from the observed thermal broadening and Doppler shift of the line. The time resolution of these measurements is about 1 mu s, sufficient to observe the fastest magnetohydrodynamic activity

    Development of pigments for thermal control coatings Final report, 17 Jun. - 16 Dec. 1965

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    Powdered metal oxide pigments by nucleation for temperature control coating

    Topological superconductivity in the extended Kitaev-Heisenberg model

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    We study superconducting pairing in the doped Kitaev-Heisenberg model by taking into account the recently proposed symmetric off-diagonal exchange Γ\Gamma. By performing a mean-field analysis, we classify all possible superconducting phases in terms of symmetry, explicitly taking into account effects of spin-orbit coupling. Solving the resulting gap equations self-consistently, we map out a phase diagram that involves several topologically nontrivial states. For Γ<0\Gamma<0, we find a competition between a time-reversal symmetry breaking chiral phase with Chern number ±1\pm1 and a time-reversal symmetric nematic phase that breaks the rotational symmetry of the lattice. On the other hand, for Γ0\Gamma \geq 0 we find a time-reversal symmetric phase that preserves all the lattice symmetries, thus yielding clearly distinguishable experimental signatures for all superconducting phases. Both of the time-reversal symmetric phases display a transition to a Z2\mathbb{Z}_2 non-trivial phase at high doping levels. Finally, we also include a symmetry-allowed spin-orbit coupling kinetic energy and show that it destroys a tentative symmetry protected topological order at lower doping levels. However, it can be used to tune the time-reversal symmetric phases into a Z2\mathbb{Z}_2 non-trivial phase even at lower doping

    Wages And The University Educated: A Paradox Resolved

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    Analysis of a new data base to study occupations and employment reveals a surplus of university graduates and a movement of many of these individuals, especially those with lower functional literacy, into high-school-level jobs; only university graduates with literacy skills commensurate with their education have received rising wages

    Research on an expert system for database operation of simulation-emulation math models. Volume 2, Phase 1: Results

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    A reference manual is provided for NESS, a simulation expert system. This manual gives user information regarding starting and operating NASA expert simulation system (NESS). This expert system provides an intelligent interface to a generic simulation program for spacecraft attitude control problems. A menu of the functions the system can perform is provided. Control repeated returns to this menu after executing each user request

    The metaphysics of Machian frame-dragging

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    The paper investigates the kind of dependence relation that best portrays Machian frame-dragging in general relativity. The question is tricky because frame-dragging relates local inertial frames to distant distributions of matter in a time-independent way, thus establishing some sort of non-local link between the two. For this reason, a plain causal interpretation of frame-dragging faces huge challenges. The paper will shed light on the issue by using a generalized structural equation model analysis in terms of manipulationist counterfactuals recently applied in the context of metaphysical enquiry by Schaffer (2016) and Wilson (2017). The verdict of the analysis will be that frame-dragging is best understood in terms of a novel type of dependence relation that is half-way between causation and grounding

    High-resolution surface plasmon imaging of gold nanoparticles by energy-filtered transmission electron microscopy

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    We demonstrate the imaging capabilities of energy-filtered transmission electron microscopy at high-energy resolution in the low-energy-loss region, reporting the direct image of a surface plasmon of an elongated gold nanoparticle at energies around 1 eV. Using complimentary model calculations performed within the boundary element method approach we can assign the observed results to the plasmon eigenmodes of the metallic nanoparticle

    UNESCO science report 2005

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