Two-dimensional transient contrasting structure evolution in an inhomogeneous media with the advection
Two-dimensional transient contrasting structure evolution in an inhomogeneous media with the advection
B. A. Alexey
The inner transition layer evolution for two-dimensional quasi-linear initial-boundary value problem for the reaction-advection-diffusion equation in an inhomogeneous media with a small parameter within the high order derivatives is considered. Within the framework of the main (zero order) sum of the asymptotic series, the position of the inner transition layer is described by the Hamilton-Jacobi equation. The potential is calculated as an integrated density function of the reaction sources within the limits of the equilibrium levels. The front line of the transition layer evolves in the same way as the constant-eikonal line (the wavefront line in the other words) for the problem of wave propagation in an inhomogeneous medium in short-wave (geometro-optical) asymptotics. The sum of the asymptotic series of zero order and first order is found, the existence gap of a smooth front line, the time of destruction of the contrasting structure are calculated.
Show AbstractThe storage ring of the Compton source of the NCPM
The storage ring of the Compton source of the NCPM
D. A. Bobylev$^{1,2}$, V. I. Shvedunov$^{1,2}$
In this paper, the magnetic structure of the storage ring of an X-ray source based on the effect of Compton backscattering and designed for use in the electron beam energy range from 35 MeV to 120 MeV is investigated. For this storage ring, the results of calculating the dynamics of the electron beam are presented and the effects of radiation damping, quantum excitation, laser damping and intrabeam scattering are considered. The dynamic aperture and energy acceptance of this ring are discussed. The results of calculating the magnitude of the spectral brightness of X-ray radiation and its change over time are presented.
Show AbstractCalculation of the effective mass of electrons and holes of a single crystal TlGaTe2
Calculation of the effective mass of electrons and holes of a single crystal TlGaTe2
A. P. Abdullayev, D. M. GAFAROVA
Based on the band structure of the compound, the extrema of the valence and conduction bands were determined and the tensor of the components of the inverse effective mass of electrons and holes was calculated.
Show AbstractPhase transition face-centered cubic crystal – homogeneous phase in helium
Phase transition face-centered cubic crystal – homogeneous phase in helium
P. N. Nikolaev
In this work, the characteristics of the phase transition face-centered cubic crystal - homogeneous phase in helium are calculated based on the correlation cell-cluster expansion. The theoretical data were compared with experimental data and good agreement was obtained. It is discussed the use of data on phase transitions in helium to estimate thermodynamic characteristics phase transition in a quantum system of hard spheres.
Show AbstractThe fine structure of pygmy and giant multipole resonances in nuclei
The fine structure of pygmy and giant multipole resonances in nuclei
S. P. Kamerdzhiev, M. I. Shitov
A brief overview of experimental and theoretical results in the field of pygmy and giant resonance energies is presented. First, E1- resonances in $^{208}$Pb, where the limit of experimental resolution in the pygmy-dipole resonance region has been reached and separate $1^-$ levels have been identified. Secondly, the most important physical results of experiments with a resolution of 50-200 keV: the significance of such experiments for gamma strength functions that determine the characteristics of nuclear reactions, and the modern physical analysis of resonance structures -- wavelet analysis -- is briefly discussed. Some results in the field of excitation energies (1-5) MeV are also discussed.
Show AbstractLimit flames combustion products stability in vertical tubes
Limit flames combustion products stability in vertical tubes
I. A. Gulyaev$^1$, K. A. Kazakov$^2$
Stability of the gas flows generated by steady near-limit flames propagating in vertical tubes is studied numerically. Basic scenarios of the burnt gas flow evolution are identified in relation to the thermal gas expansion parameter and the normal flame speed. It is shown that the realization of specific scenario essentially depends on the stagnation zone width as well as on the distance travelled by the gas from the flame front to the tube end. In particular, it is found that for sufficiently short distances, the burnt gas flows are stable provided that the stagnation zone width is less than half the tube diameter. Otherwise, an unstable flow evolution can lead to the appearance of recirculation domains and acoustic perturbations.
Show AbstractElectric dipole polarizability of magic nuclei
Electric dipole polarizability of magic nuclei
N. N. Arsenyev, A. P. Severyukhin
The correlations between the electric dipole polarizability and neutron skin thickness are studied by the magic nuclei~$^{40,48}$Ca, $^{68,78}$Ni, $^{132}$Sn, and $^{208}$Pb. The strength distribution of the $E1$~transitions is calculated within the random phase approximation model based on the Skyrme nuclear energy density functional. A comparison with the experimental data has allowed us to constrain the value of the nuclear symmetry energy $J=30-37$~MeV.
Show AbstractField emission from point diamond cathodes under continuous laser irradiation
Field emission from point diamond cathodes under continuous laser irradiation
V. I. Kleshch, I. R. Anderzhanov, R. R. Ismagilov, A. N. Obraztsov
The presented study investigates the impact of continuous laser irradiation in the visible range on the field emission properties of diamond needle-like micro-sized crystallites with a nanometer tip radius. The measurements were carried out in a vacuum diode configuration with a flat metal anode using DC voltage source. It was found that the field emission current increased under illumination, showing a direct correlation with the radiation power. The relative increase in current under the action of laser irradiation is determined by the parameters of the dark current-voltage characteristic and reaches its maximum value in the region corresponding to the minimum increase in dark current with voltage. It is shown that the most likely mechanism for the increase in current is a change in the electrical resistance of the diamond microneedle as a result of absorption of laser radiation in the presence of electron levels located in the band gap of the diamond associated with impurities or structural defects in the near surface layer of the diamond microneedle.
Show AbstractConstancy of stabilized Randall-Sundrum model with respect to quantum corrections
Constancy of stabilized Randall-Sundrum model with respect to quantum corrections
I. P. Volobuev, S. I. Keizerov, E. R. Rakhmetov
In the Randall-Sundrum model stabilized with the help of the Goldberger-Wise scalar field, the lowest order vacuum quantum corrections to the energy-momentum tensor of the scalar and tensor fields are calculated. It is shown that the corresponding vacuum energy density of the fields in the bulk leads to the Casimir effect. Using the dimensional regularization method and the Abel-Plana formula, the divergences have been isolated and the vacuum energy density has been renormalized. An analytical expression for the Casimir force is obtained and an estimate of its influence on the model parameters is made. It was found that the quantum corrections lead only to a negligibly small decrease in the distance between the branes, i.e. the model possesses constancy with respect to quantum corrections.
Show AbstractA model of surface nanorelief formation under gas cluster ion beam irradiation
A model of surface nanorelief formation under gas cluster ion beam irradiation
D. R. Bessmertniy, A. E. Ieshkin
A model for the evolution of surface nanorelief under irradiation with gas cluster ions is proposed. The model is based on consideration of individual collisions of clusters with a surface. The amount of substance sputtered from the collision area and the efficiency of its redeposition onto other surface elements are determined. The performance of the model is shown when compared with experimental data. The stages of smoothing of a harmonic relief are studied. A new measure of the effectiveness of surface smoothing is proposed.
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