802,164 research outputs found

    Sustainable monetary policy and inflation expectations

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    The author shows that the short-term nominal interest rate can anchor private-sector expectations into low inflation more precisely, into the best equilibrium reputation can sustain. He introduces nominal asset markets in an infinite horizon version of the Barro-Gordon model. The author then analyzes the subset of sustainable policies compatible with any given asset price system at date t = 0. While there are usually many sustainable inflation paths associated with a given set of asset prices, the best sustainable inflation path is implemented if and only if the short-term nominal bond is priced at a certain discount rate. His results suggest that policy frameworks must also be evaluated on their ability to coordinate expectations.Inflation (Finance) ; Interest rates ; Asset pricing

    UAV as a Reliable Wingman: A Flight Demonstration

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    In this brief, we present the results from a flight experiment demonstrating two significant advances in software enabled control: optimization-based control using real-time trajectory generation and logical programming environments for formal analysis of control software. Our demonstration platform consisted of a human-piloted F-15 jet flying together with an autonomous T-33 jet. We describe the behavior of the system in two scenarios. In the first, nominal state communications were present and the autonomous aircraft maintained formation as the human pilot flew maneuvers. In the second, we imposed the loss of high-rate communications and demonstrated an autonomous safe “lost wingman” procedure to increase separation and reacquire contact. The flight demonstration included both a nominal formation flight component and an execution of the lost wingman scenario

    Quantum Correction to Conductivity Close to Ferromagnetic Quantum Critical Point in Two Dimensions

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    We study the temperature dependence of the conductivity due to quantum interference processes for a two-dimensional disordered itinerant electron system close to a ferromagnetic quantum critical point. Near the quantum critical point, the cross-over between diffusive and ballistic regimes of quantum interference effects occurs at a temperature T=1/τγ(EFτ)2 T^{\ast}=1/\tau \gamma (E_{F}\tau)^{2}, where γ\gamma is the parameter associated with the Landau damping of the spin fluctuations, τ\tau is the impurity scattering time, and EFE_{F} is the Fermi energy. For a generic choice of parameters, TT^{\ast} is smaller than the nominal crossover scale 1/τ1/\tau . In the ballistic quantum critical regime, the conductivity behaves as T1/3T^{1/3}.Comment: 5 pages, 1 figur

    Synthesis, crystal structure and chemical stability of the superconductor FeSe_{1-x}

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    We report on a comparative study of the crystal structure and the magnetic properties of FeSe1-x (x= 0.00 - 0.15) superconducting samples by neutron powder diffraction and magnetization measurements. The samples were synthesized by two different methods: a 'low-temperature' one using powders as a starting material at T =700 C and a "high-temperature' method using solid pieces of Fe and Se at T= 1070 C. The effect of a starting (nominal) stoichiometry on the phase purity of the obtained samples, the superconducting transition temperature Tc, as well as the chemical instability of FeSe1-x at ambient conditions were investigated. It was found that in the Fe-Se system a stable phase exhibiting superconductivity at Tc~8K exists in a narrow range of selenium concentration (FeSe0.974(2)).Comment: 7 pages, 7 figures, 1 tabl

    Computer acquired performance data from a chemically vapor-deposited-rhenium, niobium planar diode

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    Performance data from a chemically vapor-deposited-rhenium, niobium thermionic converter are presented. The planar converter has a guard-ringed collector and a nominal fixed spacing of 0.25 mm (10 mils). The data were obtained by using a computerized acquisition system and are available on request to one of the authors on microfiche as individual and composite parametric current, voltage curves. The parameters are the temperatures of the emitter T sub E collector T sub C, and cesium reservoir T sub R. The composite plots have constant T sub E and varying T sub C or T sub R, or both. Current, voltage envelopes having constant T sub E with and without fixed T sub C appear in the present report. The diode was tested at increments between 1600 and 2000 K for the emitter Hohlraum, 800 to 1100 K for the collector, and 540 and 650 K for the reservoir. A total of 312 current, voltage curves were obtained in the present performance evaluation. Current, voltage envelopes from three rhenium emitter converters evaluated in the present program are also given. The data are compared at commom emitter Hohlraum temperatures

    Magnetic states of granular layered CoFe-Al\u3csub\u3e2\u3c/sub\u3eO\u3csub\u3e3\u3c/sub\u3e

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    The granular layered magnetic system Co80Fe20(t)/Al2 O3 (3 nm), where the Co80Fe20 layers of nominal thickness t form separate, almost spherical magnetic granules of typical diameter 2-3 nm between the Al2O3 spacers, was studied. We discuss measurements of the dc and ac magnetic susceptibility χ for 1 n
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