Nonlinear vacuum effects and optical properties of nonconducting crystals in intense electromagnetic fields
Nonlinear vacuum effects and optical properties of nonconducting crystals in intense electromagnetic fields
V.N. Rodionov
Based on the exact solutions of quantum equations of charged particles motion in the combination of a constant magnetic field and a wave field, the cross sections and probabilities of $e^{+}e^{-}$ photo-production and nuclear $\beta$-decay processes have been calculated. It has been demonstrated that the expressions obtained with account for the field action on the normalized characteristics of the process $\gamma^{'} +\gamma^{''} \to e^{+} + e^{-}$ can also be applied to characterize the absorption coefficients of nonconducting crystals in the field. A field-dependent instability of a proton in an intense external field has been estimated. It has been observed that conditions may arise for an effective $\beta$-transformation of nucleons at a heavy nuclei boundary.
Show AbstractDependence of particular solutions of one-dimensional nonlinear Schr$\stackrel{..}{o}$dinger-type equations on problem parameters
Dependence of particular solutions of one-dimensional nonlinear Schr$\stackrel{..}{o}$dinger-type equations on problem parameters
A.R. Frenkin
The dependence of particular solutions of generalized one-dimensional Schr$\stackrel{..}{o}$dinger-type equations on problem parameters has been studied. The relationship between weak and strong separatrix solutions has been established. The equations with different-type nonlinearities have been considered.
Show AbstractUpper and lower variational estimates in calculating the three-particle systems with exponential trial functions
Upper and lower variational estimates in calculating the three-particle systems with exponential trial functions
A.G. Donchev, N.N. Kolesnikov, V.1. Tarasov
All the formulas necessary for calculating not only the upper $E_U$, but also the lower $E_L$ variational estimates of three-particle system energy with the use of trial functions in the form of expansions in multi-dimensional exponents are obtained. The lower variational estimates with such trial functions are found for the first time. It is shown on some examples that, though $E_L$ is usually a more distant estimate of the system energy exact value $E_0$ than $E_U$, it provides also an appreciably more reliable extrapolation.
Show AbstractCalculations of electron loss cross sections for oxygen ions in gaseous media
Calculations of electron loss cross sections for oxygen ions in gaseous media
I.S. Dmitriev
In the ion energy range 0.1-200 MeV/nucleon, the cross sections $\sigma_{i, i+1}$ of electron loss by oxygen ions with charges $i=1 \div 7$ in hydrogen, nitrogen, and argon are calculated. The values of the cross sections of electron loss by multielectron ions are obtained by summing up partial cross sections $\sigma_{nl}$ of electron losses from all $nl$ ion shells. The charge composition in the oxygen ion beams after passing the specified substance layer is determined. Most calculation results are fairly consistent with the experimental data available.
Show AbstractDetection of incoherent trains of "gravity" pulses with unknown noise distrubution
Detection of incoherent trains of "gravity" pulses with unknown noise distrubution
A.V. Gusev, V.N. Rudenko
The problem of threshold level selection is discussed in a detector of incoherent train of "gravity" pulses under unknown noise distribution without using any hypothesis on the form of that distribution.
Show AbstractNonlinear collisional relaxation of two-level atoms in laser field
Nonlinear collisional relaxation of two-level atoms in laser field
B.A. Grishanin
Based on the quantum analog of the Boltzmann equation, the task of calculating the excitations of two-level atoms in the gaseous phase, taking into account their resonance dipole-dipole collisional broadening, is considered. The dependence of relaxation matrix parameters on laser field parameters induced by the field dependence of the state of colliding active atoms is analyzed.
Show AbstractPolarization effects in transverse acoustic wave reflection by nonlinear boundary
Polarization effects in transverse acoustic wave reflection by nonlinear boundary
F.M. Severin, I.Yu. Solodov, B.A. Korshak
The polarization of second-harmonic acoustic waves is theoretically studied for the case of nonlinear reflection of a linearly polarized transverse wave by a free solid boundary. Angular dependences of the generation efficiencies for different types of second-harmonic waves are calculated. It is shown that in the subcritical region, the second-harmonic waves are linearly polarized, the polarization of the reflected transverse harmonic being different from that of the primary reflected wave. In the supercritical region, the transverse second-harmonic wave becomes elliptically polarized. The basic theoretical conclusions are confirmed by experimental data.
Show AbstractTemperature behavior features of Ni1oo-xP x alloys magnetization in the region of magnetic phase transition
Temperature behavior features of Ni1oo-xP x alloys magnetization in the region of magnetic phase transition
S.D. Antipov$^1$, G.E. Goryunov$^1$, M.V. Ivanov$^2$, A.L. Kolumbaev$^1$, Yu.M. Polukarov$^2$, P.N. Stetsenko$^1$, Zhang Yiangao$^1$
The Ni$_{100-x}$P$_x$ alloy films ($x=2,44\div16,8$ ат.% Р) were synthesized by chemical deposition on copper substrates. X-ray diffraction and magnetic measurements showed that, initially, the alloy was in a nanocrystalline superparamagnetic state. Temperature studies of magnetization for the alloy with $x=16,8$ ат.% Р revealed the occurrence of anomalous heat release and heat absorption in the magnetic phase transition region.
Show AbstractEnergy spectrum of radiation defects in Pb$_{1-x}$Sn$_x$Se ($x\le0,\!06$) alloys irradiated by electrons
Energy spectrum of radiation defects in Pb$_{1-x}$Sn$_x$Se ($x\le0,\!06$) alloys irradiated by electrons
N.B. Brandt, E.P. Skipetrov, B.B. Kovalev, L.A. Skipetrova
At pressures $P\le18$ khar, galvanomagnetic effects in $n$- and $p$-Pb$_{1-x}$Sn$_x$Se ($x\le0,\!06$) alloys irradiated by electrons were studied. The metal-dielectric and dielectric-metal transitions induced by electron irradiation and hydrostatic compression of irradiated crystals were observed. These transitions were attributed to the appearance of a deep radiation defect level $E_{t1}$ near the $L_6^+$ valence hand top. An energy diagram of the pressure-induced level shifts with respect to allowed energy band edges at point $L$ of the Brillouin zone was constructed.
Show AbstractM$\stackrel{..}{o}$ssbauer study of $^{57}$Fe and $^{119}$Sn nuclei hyperfine coupling in the $\beta$-Mn$_{18}$Sn$_{2-x}$Fe$_x$ system
M$\stackrel{..}{o}$ssbauer study of $^{57}$Fe and $^{119}$Sn nuclei hyperfine coupling in the $\beta$-Mn$_{18}$Sn$_{2-x}$Fe$_x$ system
V.S. Rusakov$^1$, A.S. Ilyushin$^1$, A.S. Vinogradova$^1$, I.A. Nikanorova$^1$, V.M. Cherepanov$^2$
By measuring their $^{57}$Fe and $^{119}$Sn MOssbauer spectra, the Mn$_{18}$Sn$_{2-x}$Fe$_x$ alloys ($x=0,\!0\div2,\!0$) with the $\beta$-Mn structure were studied. The hyperfine coupling parameters of $^{57}$Fe and $^{119}$Sn nuclei in various nonequivalent lattice sites, depending on the radius of the first coordination sphere, were analyzed. The mechanisms determining the hyperfine electric interactions of $^{57}$Fe and $^{119}$Sn nuclei were considered. The predominantly covalent character of the electronic structure of $\beta$-Mn-Sn-Fe alloys was shown.
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