Is the cyclic model of Universe possible in Relativistic Theory of Gravitation?
Is the cyclic model of Universe possible in Relativistic Theory of Gravitation?
Yu. V. Chugreev
For the flat FLRW model of Universe evolution in RTG a new model of Dark Energy is proposed. It is a global scalar field Φ with the quadratic potential. It ensures cosmological acceleration at the present time and a bounce at the latе times. At the contraction stage Kazner-like growing anisotropy of Riemannian metrics will break a mass-of- the-graviton bounce mechanism near the Big Bang in FLRW case. In order to save the cyclic model one probably has to add some exotic fields, like galileons etc. There is also noncyclic option, when small enough graviton-mass-terms are significant only at the end of expansion. After bounce, during next contraction epoch, an anisotropy grows and the matter density finally reaches the Planck one.
Show AbstractTemperature changes in luminescence of mixed complexes of terbium and samarium with organic ligands based on 2,2´-bipyridyldicarboxamides
Temperature changes in luminescence of mixed complexes of terbium and samarium with organic ligands based on 2,2´-bipyridyldicarboxamides
A. V. Kharcheva$^1$, K. D. Shmelkov$^1$, Yu. G. Sokolovskaya$^1$, A. V. Ivanov$^2$, N. E. Borisova$^3$, S. V. Patsaeva$^1$
Solutions in acetonitrile of three mixed complexes of rare earth elements (terbium and samarium) with organic ligands with various pyridine substituents were studied in this work. The ratios of ligands and metals in the resulting complexes were determined, and the stability constants of samarium complexes were calculated using the spectrophotometric titration method. Measurements of absorption, emission and excitation spectra of luminescence, luminescence kinetics of solutions of mixed complexes of rare earth elements with an excess of metal relative to the ligand were carried out at various temperatures in the range 298-328 K. An increase of luminescence intensity of a samarium ion in complex upon heating has been discovered for the first time. The dependences of the luminescence quantum yield and lifetime of mixed complexes on temperature were obtained. A thermometric parameter — the ratio of the integral luminescence intensities of samarium and terbium ions — was proposed, and the temperature sensitivity coefficient of this parameter was determined for different complexes.
Show AbstractVacuum polarization in the point impurity background
Vacuum polarization in the point impurity background
Yu. V. Grats, P. -. Spirin
We consider the vacuum polarization effect near the point delta-like source. The corresponding interaction is introduced within a technique of self-adjoint extension for the Laplace operator. Such a technique was widely discussed within Quantum Mechanics; we propose it for the investigation of vacuum field effects. It allows to compute the renormalized Hadamard function and the renormalized vacuum energy density for massive real scalar field with minimal curvature coupling. The dependence of the vacuum polarization effect upon the fields's mass is analyzed.
Show AbstractThe effect of dimensional quantization effects on the effective mass of the main charge carriers in LED heterostructures with InxGa1-xN/GaN multiple quantum wells
The effect of dimensional quantization effects on the effective mass of the main charge carriers in LED heterostructures with InxGa1-xN/GaN multiple quantum wells
E. R. Burmistrov$^1$, L. P. Avakyants$^2$
The zone diagrams of LED heterostructures with multiple quantum wells InxGa1-xN/GaN are calculated by numerically self-consistent solution of the system of Schrodinger equations and Poisson electroneutrality. The effect of the electron-phonon interaction, the nonparabolicity of the dispersion law and the hybridization of the wave function on the values of the effective mass of the main charge carriers in InxGa1-xN/GaN quantum wells has been studied. The redshift of 2D plasmon resonances is associated with the temperature renormalization of the effective mass of two-dimensional carriers. To describe the temperature dependence of the effective mass, the function of displacement of the 2D plasmon resonance frequency is used.
Show AbstractCross section evaluation of the exclusive K+Λ and K+Σ0 electroproduction channels off proton with CLAS detector
Cross section evaluation of the exclusive K+Λ and K+Σ0 electroproduction channels off proton with CLAS detector
A. V. Golda$^1$, A. A. Golubenko$^{1,2}$, M. M. Davydov$^1$, E. L. Isupov$^2$, V. I. Mokeev$^3$, S. A. Savkin$^1$, V. V. Chistyakova$^1$
We report the tool for evaluation of the cross section for K+Λ and K+Σ0 electroproduction channels off proton. Within the framework of this work, we interpolated and extrapolated the structure functions of the K+Λ and K+Σ0 electroproduction channels using various algorithms for predicting the behavior of the studied observables. A set of algorithms for estimating systematic errors in the differential cross section prediction result is implemented. The program has been developed for estimating the differential cross section and structural functions using the C++ and Python libraries. For interactive work with the program, a web site was developed that allows you to visually analyze one-dimensional and two-dimensional distributions of structural functions and differential cross section.
Show AbstractUsing gamma distribution to obtain Maxwell - Renyi statistics and other generalized distributions
Using gamma distribution to obtain Maxwell - Renyi statistics and other generalized distributions
D. V. Nakashidze$^1$, A. M. Savchenko$^1$, T. N. Bakiev$^2$
We propose a universal method for performing calculations within the framework of generalized statistics generated by the parametric Tsallis, Renyi, and Sharma–Mittal entropies. The essence of the approach lies in the use of an auxiliary gamma distribution whose parameters correspond to a particular variant of the statistics. Equations are derived that allow the generalised partition function and the mean energy to be expressed in terms of canonical quantities. The effectiveness of the proposed method is demonstrated using the example of Renyi statistics. The Maxwell - Renyi distribution is obtained and its properties are calculated, on the basis of which assumptions about the possible nature of the generalised parameter are formulated.
Show AbstractModification of the surface relief of additive materials under irradiation with Ar+ ions
Modification of the surface relief of additive materials under irradiation with Ar+ ions
D. S. Kireev$^1$, K. F. Minnebaev$^2$, V. A. Kiselevskiy$^3$, A. E. Ieshkin$^4$
Additive manufacturing (AM) is a modern, developing group of technologies based not on the removal of material, but on the layer-by-layer growth and synthesis of an object according to a CAD (Computer-Aided Design) model. The main disadvantages of objects manufactured using AM technologies are a high degree of porosity and surface roughness. This work examines the possibility of modifying the surface of additive materials Ti6Al4V and AlSi10Mg using irradiation with Ar+ ions with energies in the range from 2 to 9 keV. Using SEM, the surface topography was obtained before and after irradiation and mechanical polishing. A decrease in surface porosity and roughness, as well as the influence of beam energy on the final surface topography, was demonstrated.
Show AbstractNew version of the experimental setup for the measurement of γ-quanta emission cross sections in nuclear reactions induced by 14.1 MeV neutrons
New version of the experimental setup for the measurement of γ-quanta emission cross sections in nuclear reactions induced by 14.1 MeV neutrons
Yu. N. Kopach$^1$, D. N. Grozdanov$^{1,2}$, N. A. Fedorov$^{1,3}$, T. Yu. Tretyakova$^{1,3,4}$, P. I. Kharlamov$^{1,4}$, A. V. Andreev$^{1,3}$, G. .. Ahmadov$^{1,5}$, D. .. Berikov$^{1,6}$, S. .. Dabylova$^{1,6}$, P. K. Das$^{1,7}$, A. .. Kumar$^8$, G. V. Pampushik$^3$, I. N. Ruskov$^{1,2}$, I. A. Sirakov$^2$, V. R. Skoy$^1$, P. G. Filonchik$^{1,9}$, C. .. Hramco$^{1,10}$
Within the TANGRA project framework, a new experimental setup has been constructed for the measurement of reaction cross sections (n,Xγ) in the interaction of 14.1 MeV neutrons with nuclei. The facility has a special feature: the use of the tagged neutron method. This method enables efficient separation of background and useful events, as well as accurate tracking of neutron flux. Test measurements were performed on 28Si, 12C, and 16O nuclei, and the results showed satisfactory agreement with available experimental data. This paper presents the features of the setup design and the methodology for processing the obtained experimental data.
Show AbstractCalculation of surface binding energy in NixPdy alloys using density functional theory
Calculation of surface binding energy in NixPdy alloys using density functional theory
S. S. Moskalenko, I. A. Melkozerova, A. E. Ieshkin, I. G. Kamilevich
Simulations were carried out using the VASP software package based on density functional theory. The model system consisted of a metal alloy surface with dimensions of 3x3 cells and a vacuum. During the work, surface binding energies were calculated for pure Ni and Pd metals. The values obtained were 5,32 eV and 4,65 eV, respectively, which is a good accuracy for ab initio calculations. The work also included calculations of the surface binding energy for different configurations of NiPd alloys with nickel and palladium concentrations of 66%, 50%, 33%. For each lattice type, calculations were made for both the surface binding energies of Ni and Pd. Several types of lattices were simulated, and it was found that the average values of the surface binding energy of Ni and Pd are: 5.02 eV and 4.36 eV respectively in an alloy with a concentration of Ni equal to 50%; 4.89 eV and 4.22 eV respectively in an alloy with a concentration of Ni equal to 66%; 5.12 eV and 4.40 eV respectively in an alloy with a concentration of Ni equal to 33%.
Show AbstractEffect of cluster ion bombardment on the rough polished surface of single-crystal germanium wafers
Effect of cluster ion bombardment on the rough polished surface of single-crystal germanium wafers
I. V. Nikolaev, N. G. Korobeishchikov, A. V. Lapega
The surface treatment of single-crystal germanium with an argon cluster ion beam has been investigated. The initial surface of germanium wafers was bombarded with argon cluster ions with high (105 eV/atom) and low (10 eV/atom) specific energy. Using an atomic force microscope, images were obtained and the surface topography was compared before and after cluster ion bombardment. Using the power spectral density function of roughness, surface smoothing is demonstrated in the range of spatial frequencies: 1) ν = 1−8 μm^−1 – for the high-energy mode; 2) ν = 0.7−2.5 μm^−1 – for low-energy mode.
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