A Magnetic-Field-Effect Transistor and Spin Transport

A magnetic-field-effect transistor is proposed that generates a spin-polarized current and exhibits a giant negative magnetoresitance. The device consists of a nonmagnetic conducting channel (wire or strip) wrapped, or sandwiched, by a grounded magnetic shell. The process underlying the operation of the device is the withdrawal of one of the spin components from the channel, and its dissipation through the grounded boundaries of the magnetic shell, resulting in a spin-polarized current in the nonmagnetic channel. The device may generate an almost fully spin-polarized current, and a giant negative magnetoresistance effect is predicted.Comment: 4 pages, 3 figure

trans-4-(2-Amino-5-bromo-6-methyl­pyrimidin-4-ylamino)-1-methyl­cyclo­hexa­nol

The title compound, C12H19BrN4O, represents the minor component of the two products obtained in a series of transformations involving the Grignard reaction of tert-butoxy­carbonyl-protected 4-amino­cyclo­hexa­none with MeMgBr, and subsequent inter­action of the obtained amino-substituted cyclo­hexa­nol with 4-chloro-6-methyl­pyrimidin-2-amine followed by bromination with N-bromo­succinimide. The X-ray structure showed that this product represents a trans isomer with respect to the amino and hydr­oxy substituents in the cyclo­hexyl ring; the dihedral angle between the amino­pyrimidine plane and the (noncrystallographic) mirror plane of the substituted cyclo­hexyl fragment is 33.6 (3)°. Only two of the four potentially ‘active’ H atoms participate in inter­molecular N—H⋯O and O—H⋯N hydrogen bonds, linking the mol­ecules into layers parallel to the (10) plane

Fokker-Planck Equation with Fractional Coordinate Derivatives

Using the generalized Kolmogorov-Feller equation with long-range interaction, we obtain kinetic equations with fractional derivatives with respect to coordinates. The method of successive approximations with the averaging with respect to fast variable is used. The main assumption is that the correlator of probability densities of particles to make a step has a power-law dependence. As a result, we obtain Fokker-Planck equation with fractional coordinate derivative of order $1<\alpha<2$.Comment: LaTeX, 16 page

Secondary atomization of a biodiesel micro-emulsion fuel droplet colliding with a heated wall

Using high-speed video recording, we establish the following regimes of hydrodynami

Relaxation of high-energy quasiparticle distributions: electron-electron scattering in a two-dimensional electron gas

A theory is developed for the evolution of the non-equilibrium distribution of quasiparticles when the scattering rate decreases due to particle collisions. We propose a "modified one-collision approximation" which is most effective for high-energy quasiparticle distributions. This method is used to explain novel measurements of the non-monotonic energy dependence of the signal of scattered electrons in a 2D system. The observed effect is related to a crossover from the ballistic to the hydrodynamic regime of electron flow.Comment: 6 pages, 3 figure

Fractional Kinetics for Relaxation and Superdiffusion in Magnetic Field

We propose fractional Fokker-Planck equation for the kinetic description of relaxation and superdiffusion processes in constant magnetic and random electric fields. We assume that the random electric field acting on a test charged particle is isotropic and possesses non-Gaussian Levy stable statistics. These assumptions provide us with a straightforward possibility to consider formation of anomalous stationary states and superdiffusion processes, both properties are inherent to strongly non-equilibrium plasmas of solar systems and thermonuclear devices. We solve fractional kinetic equations, study the properties of the solution, and compare analytical results with those of numerical simulation based on the solution of the Langevin equations with the noise source having Levy stable probability density. We found, in particular, that the stationary states are essentially non-Maxwellian ones and, at the diffusion stage of relaxation, the characteristic displacement of a particle grows superdiffusively with time and is inversely proportional to the magnetic field.Comment: 15 pages, LaTeX, 5 figures PostScrip

Determination of aircraft current location on the basis of its acoustic noise

In this paper the algorithm of signal detection by means passive acoustics and digital data processing is proposed. This algorithm is original and contains the processing of signals, which are received by several acoustic aerials. For signal detection the calculation of wide-band ambiguity function together with its projection on time axis are used. All the calculations are executed with the real signals. As the result the location of the aircraft on Cartesian coordinate plane is observed. The suggested algorithm is also proposed to use for measuring of aircraft noise with the aim of environmental protection

Electron-beam propagation in a two-dimensional electron gas

A quantum mechanical model based on a Green's function approach has been used to calculate the transmission probability of electrons traversing a two-dimensional electron gas injected and detected via mode-selective quantum point contacts. Two-dimensional scattering potentials, back-scattering, and temperature effects were included in order to compare the calculated results with experimentally observed interference patterns. The results yield detailed information about the distribution, size, and the energetic height of the scattering potentials.Comment: 7 pages, 6 figure