399 research outputs found
Some relations concerning k-chordal and k-tangential polygons
In papers [6] and [7] the k-chordal and the k-tangential polygons are defined and some of their properties are proved. In this paper we shall consider some of their other properties. Theorems 1-4 are proved
Some relations and properties concerning tangential polygons
The k-tangential polygon is defined, and some of its properties are proved
On algebraic equations concerning semi-tangential polygons
Some properties of equations (5) and (6) are proved (Theorem 1-2) and it was established that the positive roots of these equations are radii of a sequence of tangential semi-polygons which have the same lengths of tangents
Anderson localization of a Tonks-Girardeau gas in potentials with controlled disorder
We theoretically demonstrate features of Anderson localization in the
Tonks-Girardeau gas confined in one-dimensional (1D) potentials with controlled
disorder. That is, we investigate the evolution of the single particle density
and correlations of a Tonks-Girardeau wave packet in such disordered
potentials. The wave packet is initially trapped, the trap is suddenly turned
off, and after some time the system evolves into a localized steady state due
to Anderson localization. The density tails of the steady state decay
exponentially, while the coherence in these tails increases. The latter
phenomenon corresponds to the same effect found in incoherent optical solitons
Thermoelectrical manipulation of nanomagnets
We investigate the interplay between the thermodynamic properties and
spin-dependent transport in a mesoscopic device based on a magnetic multilayer
(F/f/F), in which two strongly ferromagnetic layers (F) are exchange-coupled
through a weakly ferromagnetic spacer (f) with the Curie temperature in the
vicinity of room temperature. We show theoretically that the Joule heating
produced by the spin-dependent current allows a spin-thermo-electronic control
of the ferromagnetic-to-paramagnetic (f/N) transition in the spacer and,
thereby, of the relative orientation of the outer F-layers in the device
(spin-thermo-electric manipulation of nanomagnets). Supporting experimental
evidence of such thermally controlled switching from parallel to antiparallel
magnetization orientations in F/f(N)/F sandwiches is presented. Furthermore, we
show theoretically that local Joule heating due to a high concentration of
current in a magnetic point contact or a nanopillar can be used to reversibly
drive the weakly ferromagnetic spacer through its Curie point and thereby
exchange couple and decouple the two strongly ferromagnetic F-layers. For the
devices designed to have an antiparallel ground state above the Curie point of
the spacer, the associated spin-thermionic parallel-to-antiparallel switching
causes magneto-resistance oscillations whose frequency can be controlled by
proper biasing from essentially DC to GHz. We discuss in detail an experimental
realization of a device that can operate as a thermo-magneto-resistive switch
or oscillator.Comment: This paper, published in J. Appl. Phys. 107, 123706 (2010), is an
expanded version of arXiv:0710.5477 (8 pages, 12 figures, two additional
authors and experimental section added
DC spin generation by junctions with AC driven spin-orbit interaction
An unbiased one-dimensional weak link between two terminals, subjected to the
Rashba spin-orbit interaction caused by an AC electric field which rotates
periodically in the plane perpendicular to the link, is shown to inject
spin-polarized electrons into the terminals. The injected spin-polarization has
a DC component along the link and a rotating transverse component in the
perpendicular plane. In the adiabatic, low rotation-frequency regime, these
polarization components are proportional to the frequency. The DC component of
the polarization vanishes for a linearly-polarized electric field.Comment: published versio
Competition and risk-taking in investment banking
How does competition affect the investment banking business and the risks individual institutions are exposed to? Using a large sample of investment banks operating in seven developed economies over 1997-2014, we apply a panel VAR model to examine the relationships between competition and risk without assuming any a priori restrictions. Our main finding is that investment banks’ higher risk exposure, measured as a long-term capital-at-risk and return volatility, was facilitated by greater competitive pressures for both boutique investment banks and full service investment banks. Overall, we find some evidence that more competition leads to more fragility before and during the recent financial crisis
Spin-thermo-electronic oscillator based on inverse giant magnetoresistance
A spin-thermo-electronic valve with the free layer of exchange-spring type
and inverse magnetoresistance is investigated. The structure has S-shaped
current-voltage characteristics and can exhibit spontaneous oscillations when
integrated with a conventional capacitor within a resonator circuit. The
frequency of the oscillations can be controlled from essentially dc to the GHz
range by the circuit capacitance.Comment: 7 pages, 9 figure
On some algebraic equations in connection with one kind of tangential polygons
This article can be considered as an appendix to article [1]. Here article [1] is completed and extended, where some new relations concerning one kind of tangential polygons and algebraic equations are established
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