2,657 research outputs found
High frequency-heated air turbojet
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
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
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
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
Historical Perspectives on the Monetary Transmission Mechanism
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
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 -body problem with the Einstein-Infeld-Hoffmann equations,
it is found that they differ from the EIH equations by Lorentz invariant terms
of order .Comment: 28 page
Electric-field control of domain wall nucleation and pinning in a metallic ferromagnet
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
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/E 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 2p resonances observed in the spectra.Comment: 7 pages, 3 figures, 2 table
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