Voltage self-sustained oscillation and phase separation dynamics in a thin layer of a weakly conducting ferromagnetic liquid with periodically emerging electrohydrodynamic flows

It is shown that voltage self-sustained oscillations, which are determined by the properties of the near-electrode layer and electrohydrodynamic flows that are periodically formed in the colloid layer, emerge for a preset direct current at the electrodes of a plane-parallel cell filled with a colloid system consisting of stabilized magnetic nanoparticles dispersed in a weakly conducting liquid. The effect of self-sustained oscillations and periodic electrohydrodynamic flows in phase separation in the colloid system is analyzed. It is found that new dynamic formations are generated, which are regions of elevated concentration of magnetite particles having the shape of labyrinths of millimeter size. The emergence of a negative real part of the permittivity of the colloid layer is detected and attributed to the fact that the normal component of the internal electric field produced by volume charges becomes codirectional with the applied field when steady-state electrohydrodynamic flows appear in the system.     

Hidden local symmetry and the reaction e+e- → \pi^{+}_{} \pi^{-}_{} \pi^{+}_{} \pi^{-}_{} at energies \sqrt{{s}} ⩽ 1 GeV

Based on the generalized hidden local symmetry as the chiral model of pseudoscalar, vector, and axial vector mesons, the excitation curve of the reaction e ⁺ e ^- → $ \pi^{+}_{}$ $ \pi^{-}_{}$ $ \pi^{+}_{}$ $ \pi^{-}_{}$ is calculated for energies in the interval 0.65 ? $ \sqrt{{s}}$ ? 1 GeV. The theoretical predictions are compared to available data of CMD-2 and BaBaR. It is shown that the inclusion of heavy isovector resonances ρ(1450) and ρ(1700) is necessary for reconciling calculations with the data. It is found that at $ \sqrt{{s}}$ ≈ 1 GeV the contributions of the above resonances are much larger, by a factor of 30, than the ρ(770) one, and amount to a considerable fraction ～ 0.3-0.6 of the latter at $ \sqrt{{s}}$ ～ m _ρ .     

Laser Gain for Inhomogeneous Boundary Conditions

Russian Physics Journal - The method proposed by the authors for solving the Helmholtz equation with homogeneous boundary conditions was verified for an elliptic cross section. The method is...     

Effective Synthetic Approach to 4-Arylpyridine-2,6-dicarboxylic Acids

Russian Journal of Organic Chemistry - A convenient synthetic route to 4-arylpyridine-2,6-dicarboxylic acid has been proposed on the basis of substituted benzaldehydes according to the Kröhnke...     

Study of the sedge (Cárex) lignin by high-resolution mass spectrometry and NMR spectroscopy

Russian Chemical Bulletin - A combination of high-resolution mass spectrometry based on an orbital ion trap and 2D NMR spectroscopy was first applied to the characterization of the structure of...     

On the Mechanism of Generation of Trichel Pulses in Atmospheric Air

JETP Letters - Discharge current pulse profiles have been recorded with a subnanosecond time resolution for a corona discharge from a negative-polarity needle functioning in the Trichel pulse...     

Magnetoelastic Properties of Yttrium–Iron Garnet Films Manufactured by Means of Ion-Beam Sputtering onto Si and GaAs Substrates

Technical Physics - The effect is studied of tensile deformations on the spectrum of the ferromagnetic resonance of submicron yttrium–iron garnet polycrystalline films manufactured by means...     

Determination of Ni,Co, and Cu in seawater by total external reflection X-ray fluorescence spectrometry

Total external reflection X-ray fluorescence spectrometry is a promising method for the highly sensitive determination of heavy metals in seawater, offering such advantages as the mobility of the used equipment and the low cost of analysis. Various methods of sample preparation to the analysis of seawater aimed at the elimination of interferences with the salt matrix were compared. It was shown that the method based on the preliminary extraction of metals as diehyldithiocarbamate complexes followed by back extraction is characterized by the highest efficiency. A procedure was developed for the determination of Ni, Cu, and Co in seawater with limits of detection at a level of 0.16–0.26 μg/L.