Vestnik (series: physical-mathematical and natural sciences), №2/2023

Khachaturyan M., Gevorgyan D. On the description of traces of functions from one class of multi-anisotropic sobolev spaces

ABSTRACT. In this paper, we obtain direct embedding theorems of different dimensions (trace theorems) for functions from the multi-anisotropic Sobolev space 𝑊₂𝔑(𝑅ⁿ) in the case of one class of completely regular polyhedron 𝔑.
Keywords:  completely regular polyhedron, multianisotropic Sobolev space, trace of a function.

Khachatryan R., Veziryan R. Design of Implementation of a Lock-free min-max Queue

ABSTRACT. For a given graph G and a proper edge t-coloring α defined on G, denote by ܵSum_g (ν, α), the sum of colors of edges neighboring ν ∈ V (G). In that case, α is called an antimagic edge t-coloring of the graph G, «G if for every pair of distinct vertices   ν₁, v₂ ∈ V (G), Sum_G (ν_1, α) ≠ Sum_G (ν_2, α). The set of graphs G, for which there exists some t, such that G admits an antimagic edge t-coloring,  is denoted by АМ.  For any graph G∈ АМ,  let ω_am mean the least positive integer t, for which G admits an antimagic edge t-coloring.  In this paper, we determine ω_am (G)  for simple cycles and regular bipartite graphs.
Keywords: Antimagic edge-coloring, edge-coloring.

Tadevosyan S., Avetisyan V., Avetisyan S. Direct and reverse moving control devices of the measuring probe during automatic near-field measurements of millimeter-wave antennas

ABSTRACT. The method of antenna measurements in the near field of the millimeter wave range is a complex system, a combination of hardware and software parts. The antenna measurement system using the near-field method consists of the following subsystems. This is a subsystem for mechanical scanning with a probe in the near zone of the antenna under test, a radio measuring subsystem, an automatic measurement control subsystem and, finally, a computing subsystem with the corresponding mathematical processing of data about the near zone of the antenna. Devices for regulating the forward and reverse stroke of the probe are included in the mechanical scanning subsystem of the probe, which closely interacts with the automatic measurement control subsystem. The importance of the accuracy of the probe's movement, its
stopping and movement lies in the accuracy of the measurements, which in the case of the millimeter range is a rather difficult task. 
Keywords:  near field, antenna under test, direct moving, probe, measurements.

Novikov A. In air on the optical properties of YAG: Ce, Li

ABSTRACT. YAG:Ce and YAG:Ce,Li crystals were obtained by the vertical directional crystallization. The absorption spectra of the samples were measured three times: immediately after growth and after each annealing. In a sample with lithium, after two annealing, the absorption in the UV region between 190 nm and 310 nm increased more strongly, which indicates a higher concentration of Ce4+ in this crystal, as compared to YAG:Ce. Also, the sample with lithium shows a slightly improved transmission in the visible region due to the effective elimination of oxygen vacancies and associated color centers.
Keywords:  yttrium-aluminium garnet, annealing, scintillator, non-isovalent impurities.

Harutyunyan L. Comparative characteristics of solar voltaic and traditional power plants

ABSTRACT. The fundamental difference between solar voltaic power plants and traditional power plants is that the generation of alternating voltage in traditional power plants is carried out by a synchronous generator, and in solar voltaic power plants by a semiconductor switching inverter. As a result, solar voltaic power plants are inferior to traditional power plants in terms of the basic technical requirements of the power system: overload capacity, stability, sinusoidal voltage waveform, voltage adjustability and reactive current. These disadvantages can be limited to a large extent when using storage buffer batteries connected between the solar panels and the inverter. .
Keywords: solar voltaic power plant, mathematical model of a solar voltaic power plant, output voltage form, load characteristics of generation, regulation of reactive power of a solar voltaic power plants.

Gevorgyan D., Gavalajyan S. Exciton states in gaas conical quantum dot

ABSTRACT. In the current article, the effective mass approximation conjoined with the Finite element method was used to study the excitonic states in a conical GaAs QD. In particular, the dependence of the exciton energy on the geometrical parameters of a conical quantum dot has been studied. Based on the obtained results, the effective band gap of the system was calculated. The lifetime of an exciton in a conical quantum dot has been estimated and shown to be in the range of nanoseconds
Keywords:  conical quantum dot, exciton, radiative lifetime, effective bandgap.

Tumoyan J., Kazaryan Sh., Hovhannisyan A.  Impact of biogenic silver nanoparticles (AgNPs) on some biochemical indicators of liver functioning in Wistar white outbreed rats

ABSTRACT. This paper presents the results of a study of the profile of the effect of biogenic silver nanoparticles stabilized in a 50% extract of O. araratum on biochemical indicators of the functioning of the liver of white outbred Wistar rats. Exposure assessment was carried out by determining the activity of enzymes such as alanine aminotransferase (ALT), aspartate aminotransferase (AST), lactate dehydrogenase (LDH) and alkaline phosphatase (ALP), as well as the content of total protein (TP) and albumin. The results of the study revealed that biogenic silver NPs lead to a slight increase in the activity of aminotransferases, in particular ALT, the increase of which is not pathological based on the reference standards of biochemical parameters of experimental animals. The activity of LDH and alkaline phosphatase also increases, which is also not pathological. There are no significant changes in the content of total protein and albumin and the values are within normal limits. In this connection, it 
Keywords:  Biogenic AgNPs, Ocimum araratum, enzyme activity, total protein, albumin.

Vardanyan L. , Hayrapetyan S. Leaves of some trees as antioxidants

ABSTRACT. Here is presented the results of studies of the antioxidant properties of leaves of English oak (Quercus robur), Georgian oak (Quercus iberica), White Willow (Salix alba) and Gommon Wolfberry (Lycium barbarum). It was shown that all studied extracts exhibit antioxidant properties. It has been established that of the studied extracts, the largest number of antioxidants is contained in the Greek oak leaf extract (1.34.10^-4 mol/l in one mg), and the white willow leaf extract exhibits the highest antioxidant activity (1.01.10⁵ mol/l. sec).
Keywords:  tree leaves, antioxidants, oxidation, cumene, ethyl acetate.