2,657 research outputs found

    High frequency-heated air turbojet

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    A description is given of a method to heat air coming from a turbojet compressor to a temperature necessary to produce required expansion without requiring fuel. This is done by high frequency heating, which heats the walls corresponding to the combustion chamber in existing jets, by mounting high frequency coils in them. The current transformer and high frequency generator to be used are discussed

    Reversal and Termination of Current-Induced Domain Wall Motion via Magnonic Spin-Transfer Torque

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    We investigate the domain wall dynamics of a ferromagnetic wire under the combined influence of a spin-polarized current and magnonic spin-transfer torque generated by an external field, taking also into account Rashba spin-orbit coupling interactions. It is demonstrated that current-induced motion of the domain wall may be completely reversed in an oscillatory fashion by applying a magnonic spin-transfer torque as long as the spin-wave velocity is sufficiently high. Moreover, we show that the motion of the domain wall may be fully terminated by means of the generation of spin-waves, suggesting the possibility to pin the domain-walls to predetermined locations. We also discuss how strong spin-orbit interactions modify these results.Comment: Accepted for publication in Phys. Rev.

    Current induced magnetization reversal on the surface of a topological insulator

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    We study dynamics of the magnetization coupled to the surface Dirac fermions of a three di- mensional topological insulator. By solving the Landau-Lifshitz-Gilbert equation in the presence of charge current, we find current induced magnetization dynamics and discuss the possibility of mag- netization reversal. The torque from the current injection depends on the transmission probability through the ferromagnet and shows nontrivial dependence on the exchange coupling. The mag- netization dynamics is a direct manifestation of the inverse spin-galvanic effect and hence another ferromagnet is unnecessary to induce spin transfer torque in contrast to the conventional setup.Comment: 4 pages, 4 figure

    Current induced domain wall dynamics in the presence of spin orbit torques

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    Current induced domain wall (DW) motion in perpendicularly magnetized nanostripes in the presence of spin orbit torques is studied. We show using micromagnetic simulations that the direction of the current induced DW motion and the associated DW velocity depend on the relative values of the field like torque (FLT) and the Slonczewski like torques (SLT). The results are well explained by a collective coordinate model which is used to draw a phase diagram of the DW dynamics as a function of the FLT and the SLT. We show that a large increase in the DW velocity can be reached by a proper tuning of both torques.Comment: 9 pages, 3 figure

    A History of International Trade Thought

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    Historical Perspectives on the Monetary Transmission Mechanism

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    This paper examines changes over time in the importance of the lending channel in the transmission of monetary shocks to the real economy. We first use a simple extension of the Bernanke-Blinder model to isolate the observable factors that affect the strength of the lending channel. We then show that based on changes in the structure of banks assets, reserve requirements, and the composition of external firm finance, the lending channel should have been stronger before 1929 than during the post-World War II period, especially the first half of this period. Finally, we demonstrate that conventional indicators of the importance of the lending channel, such as the spread between the loan rate and the bond rate and the correlation between loans and output, do not show the predicted decline in the importance of lending over time. From this we conclude that either the traditional indicators are not useful measures of the strength of the lending channel or that the lending channel has not been quantitatively important in any era.

    Research of Gravitation in Flat Minkowski Space

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    In this paper it is introduced and studied an alternative theory of gravitation in flat Minkowski space. Using an antisymmetric tensor, which is analogous to the tensor of electromagnetic field, a non-linear connection is introduced. It is very convenient for studying the perihelion/periastron shift, deflection of the light rays near the Sun and the frame dragging together with geodetic precession, i.e. effects where angles are involved. Although the corresponding results are obtained in rather different way, they are the same as in the General Relativity. The results about the barycenter of two bodies are also the same as in the General Relativity. Comparing the derived equations of motion for the nn-body problem with the Einstein-Infeld-Hoffmann equations, it is found that they differ from the EIH equations by Lorentz invariant terms of order c2c^{-2}.Comment: 28 page

    Electric-field control of domain wall nucleation and pinning in a metallic ferromagnet

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    The electric (E) field control of magnetic properties opens the prospects of an alternative to magnetic field or electric current activation to control magnetization. Multilayers with perpendicular magnetic anisotropy (PMA) have proven to be particularly sensitive to the influence of an E-field due to the interfacial origin of their anisotropy. In these systems, E-field effects have been recently applied to assist magnetization switching and control domain wall (DW) velocity. Here we report on two new applications of the E-field in a similar material : controlling DW nucleation and stopping DW propagation at the edge of the electrode

    K-Shell Photoionization of Singly Ionized Atomic Nitrogen: Experiment and Theory

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    Absolute cross sections for the K-shell photoionization of C-like nitrogen ions were measured by employing the ion-photon merged-beam technique at the SOLEIL synchrotron radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/Δ\DeltaE \approx 7,000 was achieved with the photon energy from 388 to 430 eV scanned with a band pass of 300 meV, and the 399.4 to 402 eV range with 60 meV. Experimental results are compared with theoretical predictions made from the multi-configuration Dirac-Fock (MCDF) and R-matrix methods. The interplay between experiment and theory enabled the identification and characterization of the strong 1s \rightarrow 2p resonances observed in the spectra.Comment: 7 pages, 3 figures, 2 table
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