The role of radial motion and bends of the disk in the galactic dynamo
The role of radial motion and bends of the disk in the galactic dynamo
B.G. Zinchenko, O.V. Pilipenko
Proceeding from the theory of perturbations, the effect of disk bends and radial flows on the dynamo in a thin disk has been considered. Taking the Galaxy and the spiral galaxies M51 and M81 as an example, it has been established that the role of both factors is not great. The weak influence of the radial flows is explained by the character of their dependence on the radius. The role of the disk bends mainly reduces to an effective change of the rotation curve.
Show AbstractStructural defects in fluoride single crystals for laser applications
Structural defects in fluoride single crystals for laser applications
N.B. Brandt, L.I. Devyatkova,, E.V. Ralko
The introduction of activating $Yb^{3+}$ and $Еr^{3+}$ ions belonging to the right-hand subgroup of the lanthanide series is shown to affect the mechanisms of structure formation in the $BaY_2F_8$ and $LiYF_4$ fluoride matrices. For the optical applications, it is essential that these crystals exhibit two types of microtwin structures corresponding to two types of polymorphic transformation. Another important finding is the appearance in $Еr^{3+}$-doped crystals of active centers responsible for the formation of a structure essentially different from that of the $Yb^{3+}$ activated matrix.
Show AbstractPhysical properties of $Cu_xMn_{1-x}Cr_2S_4$ solid solutions
Physical properties of $Cu_xMn_{1-x}Cr_2S_4$ solid solutions
L.I. Koroleva, A.I. Abramovich, S.D. Batorova, M.G. Mikheev, Ya.A. Kesler
Magnetic and electrical properties of solid solutions of the $Cu_xMn_{1-x}Cr_2S_4$ system have been studied for $x$ = 0; 0.1; 0.2. It has been found that the magnetic moment of these compounds measured at 4.2 K increases with $x$ and corresponds to a valence distribution $\vec{Cu_x^{2+}}\vec{Mn_{1-x}^{2+}}Cr_2^{3+}S_4^{2-}$. The introduction of copper in the ferrimagnetic semiconductor $MnCr_2S_4$ leads to a significant increase in the Curie temperature (above 300 K) and retention of the semiconductor type conductivity. Thus, we have discovered new nondegenerate semiconductors with magnetic ordering temperatures above the room temperature, which is an important factor for their practical application. It is suggested that the growth of $Т_с$ is due to the existence of a strong s-d exchange interaction in compositions with $x$ = 0.1 and 0.2. The magnitude of this interaction is estimated at $AS\approx 0,4$ eV.
Show AbstractElectron gas in a constant electromagnetic field
Electron gas in a constant electromagnetic field
V.R. Khalilov
The thermodynamic potential of a nonrelativistic gas of electrons (which possess an anomalous magnetic moment) in crossed, uniform electric and magnetic fields has been constructed. The results obtained are used to explain the features of the normal quantum Hall effect in two-dimensional systems.
Show AbstractThe feasibility of controlling the parameters of two-component optical solutions
The feasibility of controlling the parameters of two-component optical solutions
V.A. Vysloukh, E.A. Kolomiitseva, A.N. Matveev
The feasibility of controlling the amplitude, duration and frequency of two-component optical solitions formed in two-mode fiber light guides, has been studied analytically and numerically.
Show AbstractFlavor conservation in neutral weak currents and the spin structure of the proton
Flavor conservation in neutral weak currents and the spin structure of the proton
Z.R. Babaew$^1$, L. Gelmi$^2$, V.S. Zamiralov$^2$, S.N. Lepshokov$^2$
It is shown that the use of SU(4) and SU(6) groups in analysis of neutral axialvector pp-transitions substantially changes the relation between the singlet and nonsinglet parts of the Ellis-Jaffe rule of sums and partly helps in solving the problem of "spin crisis".
Show AbstractOn the effect of explosion compression of laser pulses
On the effect of explosion compression of laser pulses
B.S. Azimov, M.M. Sagatov
It is reported that explosive self-compression of pulses can be obtained in systems with a nonlinear response of higher orders.
Show AbstractSpectral characteristics of hematoporphyrin fluorescence in a liposome suspension: effects of temperature, ionic strength, and incubation time
Spectral characteristics of hematoporphyrin fluorescence in a liposome suspension: effects of temperature, ionic strength, and incubation time
K.G. Katysheva, E.B. Chernyaeva, A.F. Mironov, V.D. Rumyantseva
Fluorescence spectroscopy with numerical resolution of spectral curves by the Alentsev method has been used to study the interaction of hematoporphyrin with a lipid bilayer of liposomes. The effects of temperature, ionic strength of the solution, and incubation time have been investigated.
Show AbstractThermal conductivity of triglycine selenate crystal in the 100-320 K temperature range
Thermal conductivity of triglycine selenate crystal in the 100-320 K temperature range
B.A. Strukov, A.A. Belov
An anomalous temperature dependence of the thermal conductivity of the triglycine selenate crystal has been observed in the region of phase transition. The results are interpreted on the assumption ·of scattering of acoustic phonons by disordered elementary dipoles of the crystal lattice.
Show AbstractHigh-power acoustic beams: self-action of discontinuous waves, focusing of pulses, and extracorporeal lithotripsy
High-power acoustic beams: self-action of discontinuous waves, focusing of pulses, and extracorporeal lithotripsy
O.V. Rudenko, O.A. Sapozhnikov
This paper is a review of the studies of high-power acoustic beams, the results of their practical use and prospects for the future. A simplified self-consistent system of equations is presented to describe the behavior of an acoustic beam in liquid, with consideration for the excitation of the entropy and vortex modes and their reverse effect on the acoustic field. Experiments on thermal self-focusing of both quasi-harmonic and discontinuous waves are described, and the self-focusing of sawtooth waves is computed in a geometrical acoustics approximation. The possibility of inertialess self-focusing of sound in a medium with cubic nonlinearity is discussed. The state of the art of extracorporeal lithotripsy - a rapidly developing field at the junction of medicine and nonlinear acoustics is reviewed, and methods for calculating the focusing of high-pow acoustic pulses are described.
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