On nonlinear theory of electromagnetic wave scattering by the density-modulated nonrelativistic electron beam in the anomalous Doppler mode
On nonlinear theory of electromagnetic wave scattering by the density-modulated nonrelativistic electron beam in the anomalous Doppler mode
Yu.V. Bobylev, V.A, Panin
The nonlinear dynamics of electromagnetic wave scattering by a dense monoenergetic electron beam, premodulated in density, is studied. Analytical formulas for the amplitudes of interacting waves and the characteristic evolution time of the processes are obtained. It is found that increasing the beam modulation depth greatly reduces the instability decay time. The wave saturation amplitudes are almost independent of the modulation depth.
Show AbstractMicroenvironment effects on the spectral-kinetic properties of firefly luciferin
Microenvironment effects on the spectral-kinetic properties of firefly luciferin
L.Yu. Brovko, E.Yu. Cherednikova, A.Yu. Chikishev, E.A. Chudinova
The fluorescent properties of luciferin-substrate and an analog of the light emitter in the bioluminescent system of fireflies have been studied depending on luciferin microenvironment and structure. For the phenolate form of luciferin, which is a fluorophore analog, a linear dependence between the position of its fluorescence spectrum maximum and the solvent orientational polarizability is observed. The microenvironment of the bioluminescent reaction substrate is shown to be nonhydrophobic.
Show AbstractNumerical simulation of light scattering in a turbid medium with moving particles as applied to medical optical tomography
Numerical simulation of light scattering in a turbid medium with moving particles as applied to medical optical tomography
D.V. Kudinov, A.V. Priezzhev
The propagation and scattering of light in model biological tissues containing moving particles are studied by numerical Monte Carlo simulation using the detected signal time resolution.
Show AbstractAnomalies of dielectric and acoustic characteristics of the TGS crystal in the phase transition region under nonuniform pressure conditions
Anomalies of dielectric and acoustic characteristics of the TGS crystal in the phase transition region under nonuniform pressure conditions
O.Yu. Serdobol'skaya, V.A. Rumyantseva
Temperature dependences of permittivity and sound velocity and damping near the second-order transition in crystals subjected to nonuniform uniaxial pressure are calculated. The presence of pressure gradients causes broadening of the temperature range within which physical property anomalies are observed. The most substantial changes in the sound damping occur when the pressure gradient is normal to the wave vector of acoustic wave.
Show AbstractM$\stackrel{..}{o}$ssbauer study of mackinawite and tochilinite
M$\stackrel{..}{o}$ssbauer study of mackinawite and tochilinite
V.S. Rusakov$^1$, N.I. Chistyakova$^1$, S.V. Kozerenko$^2$, V.V. Fadeev$^2$
The M$\stackrel{..}{o}$ssbauer spectra of synthetic mackinawites and tochilinites were recorded. The observed differences in isomeric and quadrupole shift values for the $^{57}$Fe components in the spectra of mackinawite and tochilinite sulfide layers were analyzed. The structure of tochilinite was found to contain equal numbers of conjugate FeS and (Fe, Mg)(OH)$_2$ layers with Mg$^{2+}$ ions present only in brucite layers, largely in one of two observed nonequivalent sites.
Show AbstractEffect of ultrasound and light on CdS dissipative properties. 1. Low-resistance crystals
Effect of ultrasound and light on CdS dissipative properties. 1. Low-resistance crystals
G.V. Bushueva, G.M. Zinenkova, I.G. Polyakova, N.A. Tyapunina
The influence of ultrasound on the dissipative properties of low-resistance CdS crystals is experimentally studied. It is shown that the main contribution to internal friction in lowresistance samples is made by dislocation mechanisms of ultrasound absorption. The changes that occur in the "dislocation-pinning points" system under the influence of ultrasound are analyzed at various deformation amplitudes.
Show AbstractCalculation of eigenvalues of third boundary-value problems for the Bessel equation
Calculation of eigenvalues of third boundary-value problems for the Bessel equation
V.P. Modenov
The eigenvalues of the Sturm-Liouville problems for the Bessel equation with boundary conditions of the third kind have been calculated by the differential-parametric method.
Show AbstractCalculation of nonlinear mechanical processes in inhomogeneous plates
Calculation of nonlinear mechanical processes in inhomogeneous plates
G.N. Medvedev, B.I. Morgunov
The problem of a round plate equilibriwn under a constant concentrated force applied at the plate center has been solved. The plate consists of a homogeneous isotropic base and a fairly inhomogeneous (in particular, multilayer) coating much thinner than the base. The concentrated force magnitude is such that the plate sag and the coating thickness are of the same order. The sag is determined by the asymptotic method. The calculation results can be applied in approximate determination of elastic characteristics of thin coatings.
Show AbstractHigh-efficiency source of bremsstrahlung. Can the radiation quality of a bremsstrahlung source be controlled?
High-efficiency source of bremsstrahlung. Can the radiation quality of a bremsstrahlung source be controlled?
V.K. Grishin, B.S. Ishkhanov, S.P. Likhachev, D.A. Rodionov
By computer simulation, the efficiency of a new unconventional scheme of bremsstrahlung generation has been studied. The scheme is based on the electron beam's repeated transmission through a thin target. This is achieved by using a special focusing magnetic field that returns the scattered electrons back to the target. In the scheme, an almost triple increase of the radiation yield energy and a decrease of the angular divergence of bremsstrahlung photons have been observed.
Show AbstractHigh-current free-electron laser as an oscillator. Starting conditions
High-current free-electron laser as an oscillator. Starting conditions
V.K. Grishin, T.A. Novikova
The operation of a high-current free-electron laser oscillator in the mode of a collective electromagnetic wave excitation is discussed. The starting conditions for launching the device are evaluated. The feasibility of implementing the collective oscillator mode in modern electron accelerators is demonstrated.
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