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Deep Convolutional Neural Networks (CNNs) have exhibited remarkable eficacy in data analysis across various domains of physical research. Within the realm of particle and high-energy physics, an imperative challenge revolves around the scrutiny of particle tracks acquired through track detectors, exemplified by liquefied argon time projection chambers (LArTPCs). These cutting-edge neural networks have showcased unparalleled performance in tackling this intricate task, demonstrating their profound potential in enhancing particle track analysis. Since the scalability requirement is imposed on neutrino detectors, it is also imposed on CNN model implementations. The scalability for LArTPC data processing is achieved due to the sparsity of the data, which have the form of thin trajectories. To process sparse data, subspecies sparse convolutional networks (SSCNs) and sparse tensor networks (STNs) have been proposed. In this paper, we present the results of semantic segmentation of the LArTPC-simulated PILArNET data using STNs and test various modifications of the classical U-Net architecture: Attention U-ResNet, U-ResNet3+, U-ResNet with an additional deep supervision block, as well as loss functions: focal loss, balanced cross-entropy to improve the accuracy of Michel electron identification. The best results were obtained for balanced cross-entropy. Further improvement is possible by combining several methods. [ABSTRACT FROM AUTHOR]

We analyze the possibilities of detecting a signal in the hydrogen 21 cm line, which was formed in the early universe during the Dark Ages, using the Ukrainian radio telescopes UTR-2 and GURT of the National Academy of Sciences of Ukraine. As a result of cosmological expansion, this line is shifted to the decameter range of wavelengths (λobs ≈ 18 m, νobs ≈ 16 MHz) and is in the band of operating frequencies of these telescopes. The brightness temperature of the predicted sky-averaged global signal ranges from ∼ −0.08 to ∼ 0.02 K, depending on the cosmological model. Such a weak signal is a big challenge even for the world's largest radio telescope in the decameter wavelength range UTR-2, since the signal level of the synchrotron radiation of the Galaxy at these frequencies is 20 000-40 000 K. The paper highlights the peculiarities of spectroscopy at decameter waves, interfering factors of natural and instrumental origin and ways to eliminate them in order to reliably detect the signal in the 21 cm line, which can become an important source of information both about the environment in which the first stars and galaxies were born, and about the nature of dark matter particles and the magnitude of primordial magnetic fields. It was concluded that the detection of such a signal using the most sensitive radio telescopes of the decameter wavelength range is quite possible (with a frequency accumulation of 25 MHz, the detection time will be ∼ 50 days) and can be implemented in the coming years of peace in Ukraine. [ABSTRACT FROM AUTHOR]

Samuil Kaplan (1921-1978) was a productive and famous astrophysicist. He was affiliated with a number of scientific centers in different cities of the former Soviet Union. During the earliest 13 years of his career, namely in 1948-1961, he worked at the Lviv University in Ukraine. In the present paper, the Lviv period of his life and scientific activity is described on the basis of archival materials and his published studies. Kaplan arrived in Lviv in June 1948, the same month when he obtained the degree of the Candidate of Science. He was a head of the astrophysics sector at the Astronomical Observatory of the University, a professor of the department for theoretical physics, as well as the founder and head of a station for optical observations of artificial satellites of the Earth. He was active in the organization of an astronomical observatory outside the city. During the years in Lviv, Kaplan wrote more than 80 articles and 3 monographs in 9 areas. At that time, his focus was on the stability of circular orbits in the Schwarzschild field, on the white dwarf theory, on space gas dynamics, on cosmic plasma physics and turbulence, on the acceleration of cosmic rays, on the physics of interstellar medium, on the physics and evolution of stars, on cosmology and gravitation, and on the optical observations of the Earth's artificial satellites. Some of his findings are fundamental to the development of theory in those fields as well as of observational techniques. The paper presents a complete bibliography of Kaplan's works published during the Lviv period and reviews his respective scientific achievements in the light of the current state of research in those areas. [ABSTRACT FROM AUTHOR]

The review presents the results of modeling of the solvation of nanoparticles with deep eutectic solvents that act as stabilizers of metal nanoparticles, which provide a new platform for nanoparticle technology. It is calculated that there is a slower dynamics of solvent molecules, i.e., a slowing down of water near solutes. Such water has limited movement and cannot be organized into tetrahedral forms, in contrast to water in volume. Also, the paper describes systematic studies of the adsorption configuration, distribution density and adsorption energy of molecules H$_{2}$O, CO$_{2}$, CH$_{4}$, N$_{2}$, C$_{8}$H$_{18}$ and fluorocarbons C$_{3}$F$_{8}$ and C$_{5}$F$_{12}$ on the surface of kaolinite (0 0 1). Water adsorption is initiated and occurs due to the growth of clusters around surface groups, which is mainly regulated by the interactions of hydrogen bonds. Further, the paper investigates theoretically physical and mechanical properties of nanoscale systems, in particular, nanotips, amorphous carbon monolayer and nanoparticles. It is shown that the single-layer amorphous carbon is surprisingly stable and is deformed with a high ultimate strength without the propagation of cracks from the point of failure. The sliding on amorphous polyethylene and silicon studied using the method of molecular dynamics is described. The paper also discusses the dependencies of the friction force, acting on nanoparticles, on their velocity and sizes, in particular, the contact area, the structure and the type of the material, as well as on the direction of their shear and temperature. At an angle of rotation $ 45^\circ $, the silicon friction forces reach a minimum value, which can be termed superlubricity. The molecular dynamics modeling of the surface of carbon nanotubes, chitosan, polyvinyl acetate, titanium dioxide, $α$-quartz and zeolite is described to solve application problems ranging from reaction control to targeted delivery and creation of new drugs. The general principles have been identified that artificial water channels made of carbon nanotubes porins must satisfy, which can serve as a basis for further experiments. The organic modification mainly forms a modifier layer by crosslinking the hydrogen bond with the substrate, the flatness of the modified layer is strongly influenced by the type and concentration of the modifier. [ABSTRACT FROM AUTHOR]

Precise analysis of complex gas mixtures is an urgent task today, since its accuracy and quality is important not only for human health, but also for the ecology of population centers or the planet as a whole. Traditional methods of gas environment analysis are imperfect, and those that have the necessary sensitivity and selectivity do not yield results in a particularly short time. Nowadays, the Fabry- Pérot interferometry is used for research in a significant number of industrial and scientific areas. The analysis of the works presented in this paper confirms the relevance of research in the field of multibeam interferometry and the prospects of developing modifications of the Fabry- Pérot interferometer. The article is devoted to classical optical correlation methods for the analysis of gas mixtures with a quasi-periodic structure of the spectrum. A modification of the analyzer was developed and it was shown that the use of the modified Fabry- Pérot interferometer as a correlation mask ensures the express realization of the selectivity of the measurement components. An experimental study was conducted to test the possibility of scanning the SO2 absorption spectrum in the 220 nm region. Laboratory tests of the described layout of the SO2 analyzer demonstrated its high metrological parameters. The main reported error was 1% on the 0 -10000 ppm scale and 10% on the 0 -1000 ppm scale. The length of the cuvette was 170 mm, the warm-up time of the model was 30 minutes, the minimum measured concentration was 25 ppm. We can state that the correlation masks based on the IFP can be widely used for the analysis of gas components with a quasi-periodic structure of the spectrum. Compared to other devices of a similar type, they have a much higher luminous intensity: U = ΩA, where Ω is the solid angle; A is the light diameter of the IFP with the same resolution. This is crucial for remote instruments [V. R. Kozubovskii, Yu. Yu. Bilak, Ukr. J. Phys. 66, 664 (2021)]. In addition, their small weight and dimensions allow one to create portable devices based on them. However, since the IFP is a multi-beam interferometer, the procedure for optimizing its parameters is rather complicated, although technical methods for solving this problem exist [V. R. Kozubovskii, V. L. Goldovskii, O. D. Kraysler, AS 1182345 USSR, MKI G01N 21/61]. The conducted analysis and research open up new opportunities for the optimization of interferometric devices and interferometric methods of gas analysis. [ABSTRACT FROM AUTHOR]

The paper presents the results of the studies into the photoluminescence of cytosine molecules in a neutral liquid medium induced by the radiation of a xenon lamp with a wavelength of 280 nm. It was found that the luminescence is represented by a wide band with a vague threshold at a wavelength of 340 nm and a blurred maximum in the spectral region of 365-380 nm. It is shown that the presented luminescence curve reflects fluorescence, while phosphorescence is absent entirely. The lack of phosphorescence can be explained by the effect of the solvent. The obtained results are compared with the data of known studies. The discrepancies found may be primarily due to the pH of the solvents used in the previous studies. It is the first time that experiments with the excitation of luminescence of a neutral liquid solution of cytosine molecules under the simultaneous action of xenon lamp radiation with a wavelength of 280 nm and a continuous laser beam with a wavelength of 530 nm and a power of 0.25 W have been performed. It has been established that under these experimental conditions the luminescence curve acquires a qualitatively new form - the luminescence threshold is shifted to the short-wavelength region, and the luminescence curve has an additional maximum at a wavelength of 410 nm. An explanation of the physical nature of this phenomenon is given, which is that the intense electromagnetic field generated by the laser promotes the efficient formation of singlet exciters of cytosine (photodimers). In the process of their decay, cytosine photodimers form excited monomers in singlet states which, by intercombinational conversion (intersystem crossing), intensively populate metastable triplet states. The radiation decay of the formed metastable triplet states causes phosphorescence, which is the reason for the appearance of the second maximum in the wavelength range of 410 nm. Attention is drawn to the fact that metastable triplet states play a key role in the photochemistry of nucleic acid bases and presumably will have a major impact on the development of new biotechnologies. [ABSTRACT FROM AUTHOR]

The paper reports the effect of low-temperature annealing (up to 150°C) and light irradiation from a quartz mercury lamp (up to 20 min) on the structural, optical, and electrical properties of Indium tin oxide (ITO) films. 0.8 μm thick ITO films were obtained by RF magnetron sputtering of a commercial target on the optically transparent glass substrates in an argon atmosphere without heating. Information about the morphology of the ITO films' surface was obtained and the surface parameters were calculated using the method of atomic force microscopy. It has been found that the low temperature annealing for one hour and short-term irradiation with a quartz mercury lamp lead to an increase in the average size of crystallites and root-mean-square (RMS) surface roughness, a decrease in the resistivity of ITO films as well as an increase in the optical transparency in the visible spectral range. After annealing the ITO film at 150°C, the average crystallite size and RMS roughness of the surface increased approximately three times, and after 20 min irradiation – approximately 1.6 times, respectively. The lowest optical transparency in the visible spectral range among the studied experimental samples was found to be for the non-annealed and non-irradiated ITO films, whereas the highest – for the samples annealed at the highest temperature (150°C) and irradiated for 5 min with the light from the DRT-125 lamp. On the basis of the analysis of optical absorption spectra of ITO films, we detected an increase in their optical band gap from 3.59 eV for the unannealed film up to 3.66 eV with an increase in the annealing temperature of the samples up to 150°C. The resistivity of ITO films decreases with an increase in the annealing temperature up to 150°C and with an increase in the irradiation time with a light of the quartz mercury lamp up to 20 minutes. These results may be useful in the engineering of electronic devices based on the materials of low thermal stability. [ABSTRACT FROM AUTHOR]

Every year, human energy consumption is constantly growing, so the role of nuclear energy will only increase over time. However, the reserves of 235 which is the main fissile nuclide in nuclear energy, are limited and should be depleted in the coming decades. But this problem can be avoided if we use the huge reserves of 238 U. This article aims to investigate the feasibility of implementing one of the regimes of a fundamentally new and not yet practically implemented process in nuclear energy – the nuclear traveling wave in a uranium-plutonium medium, where plutonium-239 is formed from 238 U. A nuclear traveling wave may form in a uranium-plutonium medium as a moving wave of plutonium-239 fission. This paper considers the possibility of the formation of such a wave in a spherical uranium-plutonium medium, and the study is conducted in spherical geometry. A majority of works studying the traveling wave mode of nuclear fission consider 1D or cylindrical 3D geometry. There are only a few works devoted to the study of this problem in spherical geometry. It should also be noted that the nuclear reactions considered in the present paper involve the participation of epithermal neutrons, which also significantly distinguishes our work from previous works on this topic, because most of them consider thermal neutrons. Since this problem is spherically symmetric, it allowed us to replace 3D modeling of the whole sphere with 1D modeling along the radius of this sphere. We have developed kinetic equations describing a nuclear traveling wave and modeled it by numerically solving these kinetic equations. An improved explicit-implicit numerical calculation scheme was used, which allowed us to increase the temporal step of the simulation. [ABSTRACT FROM AUTHOR]

This paper investigates the changes in the properties of a bulk amorphous metallic alloy based on the ferrum (Fe55Ni8Co6)69-(Mo4Cr2V1)7-Al2-(P9C6B5Si2)22 under the influence of an alternating magnetic field (AMF). The level of the structural ordering of the bulk samples is higher than that of their tape counterparts. A slower cooling rate causes a partial nanocrystallization. The surface of such bulk samples is covered by surface layers, which were formed during the synthesis. These layers determine the corrosion resistance of amorphous alloys in the investigated solutions. After holding the samples in the AMF, some alteration of their elemental composition can be observed. An analysis of the electrochemical characteristics of the alloy samples under the conditions of cyclic scanning of the electrode potential indicates a higher corrosion resistance of the tested samples in a solution of hydrochloric acid. The lowest corrosion resistance was in the aqueous NaOH solution. During multiple cyclic polarization of bulk samples in aggressive media, a passivation of the surface occurs, and the destruction of the surface protective layers. The samples of the alloy (Fe55Ni8Co6)69-(Mo4Cr2V1)7-Al2-(P9C6B5Si2)22 modified by an alternating magnetic field have increased corrosion resistance in a 0.5 M aqueous solution of NaCl and HCl. By choosing the duration of the modification in the alternating magnetic field, it is possible to change the electrochemical parameters of the alloy (Fe55Ni8Co6)69-(Mo4Cr2V1)7-Al2-(P9C6B5Si2)22. An alternating magnetic field contributes to the diffusion of atoms in the bulk, which will determine not only the electrochemical parameters of amorphous alloys, but also other physical and chemical properties of a multicomponent sample. Under the influence of AMF, the electrical resistance of the amorphous samples is significantly reduced with increasing exposure to the magnetic field [ABSTRACT FROM AUTHOR]

The paper describes the accelerator Mikrotron M-30 (1-18 MeV) of the Institute of Electronic Physics of the National Academy of Sciences of Ukraine and its main characteristics. Also, it briefly reviews articles on the formation of radiation fields and discusses their characteristics for nuclear physics installations. It includes application of various methods of measuring the currents of charged particles, methods of detecting radiation Fields using various recording media and changing the spatial distribution using attening lters. Attention is also paid to an alternative low-cost registration method using commercial window glass. For the Mikrotron M-30 accelerator, parameters of the radiation fields were investigated on a metrological bench oriented along the electron beam at distances of 0-400 cm from the M-30 beam output node. Diametric characteristics were determined using ionization chambers of the ROBOTRON dosimeter and a Faraday cylinder designed for diagnostics of electron beams with energies up to 30 MeV. In this work, to control the spatial uniformity of the radiation field, we used a registration method based on glass plates; the degree of uniformity of the radiation field was determined by a change in their optical characteristics, namely, the degree of darkening. For correctness of the obtained distributions, the radiation dose was limited to the region of linearity of glass darkening from the absorbed dose. The use of a radiation shaper ensured irradiation of samples with radiation of a uniform Field in the irradiation plane of 30%, which satisfies the conditions of radiation tests for most objects. Analytical dependencies of the radiation dose on the distance to the output node M-30 were obtained using a Faraday cylinder. The combination of these dose dependencies of glass darkening, the spatial homogeneity of the fields, along with the dose dependence on the distance to the source node, made it possible to develop protocols for dosimetric tracking of the irradiation process for materials and devices for various purposes. [ABSTRACT FROM AUTHOR]

This paper presents the results of ultrasonic measurements in trigonal LiTaO3 crystals. The samples of direct section with faces perpendicular to the main crystallographic axes and X/45 sections of LiTaO3 crystals were manufactured for experimental studies. The velocities of longitudinal and transverse acoustic waves along the three principal crystallographic axes and two additional axes in theYZ plane in trigonal crystals of point group 3m LiTaO3 crystals were measured using the pulse-echo overlap method. In the piezoelectric crystals, elastic and electrical properties are related and the propagation of an acoustic wave is accompanied by the appearance of electric fields, which must be taken into account in the calculations. The relations for the complete determination of all components of the matrices of elastic stiffness and piezoelectric coefficients based on all necessary acoustic wave velocities measured were derived from the Christoffel equation for the piezoelectric crystals. Using the obtained ratios, all components of the tensors of piezoelectric coefficients, elastic stiffness constants, as well as all elastic compliances of LiTaO3 crystals are calculated. The obtained results are consistent with the literature data and will be used in further measurements and calculation of the spatial anisotropy of induced (electro-, piezo- and acousto-optical) effects on the same crystal samples in order to select the most effective geometry of their possible practical use. [ABSTRACT FROM AUTHOR]

This paper presents a short review of the activities of physicists -- the full members of the Shevchenko Scientific Society in Lviv (abbreviated as NTSh -- from its name in Ukrainian: {\em Naukove tovarystvo imeni Shevchenka}). The society was founded in Lviv in 1873 and named after famous Ukrainian poet, writer, artist, public and political figure Taras Shevchenko. After reorganization in 1892, the society came to resemble a typical scientific association, and it was in fact the first Ukrainian Academy of Arts and Sciences. Structurally, in consisted of three sections, one of them was devoted to mathematics, natural sciences and medicine. NTSh was dissolved by the Soviet authorities in 1940; in 1947 it resumed its activities in Western Europe and in the USA; in 1989 it was reactivated in Ukraine. In this paper, we analyze the activities of the physicists that received the title of NTSh full members (academicians) by 1940. Different fields of physics were represented in the society during this period, and among the full members of the NTSh 21 scientists were engaged in physics. Publications in the field of physics appeared regularly in the {\em Collection of the mathematical-natural sciences-medical section of NTSh} -- a total of 74 articles were published on physical subjects, including 3 terminological and 10 bibliographic ones. The physicists took an active part in the organization and activities of the clandestine Ukrainian university in Lviv (1919-1925). Papers of NTSh full members appeared in leading European physical journals. Internships in leading European centres of physical thought were widely practiced. At the beginning of 1920s, physicists from other countries were elected as NTSh full members. Among them were Max Planck, Albert Einstein, Stepan Timoshenko, Mykola Krylov, Dmytro Rozhansky, Abram Ioffe. [ABSTRACT FROM AUTHOR]

The paper draws attention to some theoretical problems of the Standard Model. In particular, the “phi-four” self-action of the Higgs field in the Standard Model is not a consequence of the derivatives “extension” in order to localize some symmetry. The same applies to the Yukawa interaction of the fermion fields with the Higgs field. The only manifestation of such interactions which are being discussed is the mass generation by particles of the Standard Model. Therefore it is unclear how the existence of such interactions can be confirmed experimentally. In the paper, it is proposed to consider the Higgs boson as a bound state of two gauge bosons and describe it by the multi-particle fields method [13, 14]. Within this approach, the self-action of the Higgs field is the consequence of the self-action of a non-Abelian gauge field, i.e. it is not a manifestation of a “new” non-gauge interaction. Unfortunately, within the proposed approach it is impossible to describe the Yukawa interaction in a similar way. Moreover, the “unnatural” sign in the Lagrangian under the squared Higgs field is not postulated as in the Standard Model, but it is the result of the dynamic equations of the two-particle gauge field. Therefore a physical interpretation of the spontaneous symmetry breaking is proposed by analogy with the phenomenon of the critical condensation. The bound state of two gauge bosons is described by the two-particle gauge field that takes values on the linear space of weak-isospin second rank tensors. Under the global group SU(2)-transformations, this linear space can be decomposed into a direct sum of invariant subspaces: tensors multiple of unit tensor, antisymmetric and symmetric tensors with zero trace. If we write the Lagrangians of these fields, the local SU(2)-symmetry of these Lagrangians will be achieved by the derivatives “extension”. Thus, the interaction of irreducible tensor fields with the Higgs field can be introduced. It is shown that the interaction of the antisymmetric part of the field with the gauge field contributes to the mass of W±-bosons, and the interaction of the symmetric part with a zero trace with the gauge field contributes to the mass of all three gauge bosons, as W± and Z0-bosons. Hence the parameters of the model can be given that the Z0-boson mass will be greater than the mass of the W±-bosons, as required by the experiment. [ABSTRACT FROM AUTHOR]

Context. The paper presents a computational scheme and a number of techniques for increasing the efficiency of mathematical modeling of the energy characteristics of metal clusters with vacancies. The object of the research is the process of calculating wave functions and finding eigenvalues using the Numerov and the shooting methods. Objective. The objective of the research is to improve the quality of the calculation of the wave functions of electrons in a metal cluster by using optimally selected methods and techniques in the computational scheme, to ensure the adequacy, stability and cost-effectiveness of self-consistent calculations of the energy characteristics of metal clusters by limiting the change in the electrostatic potential within a single iteration, choosing the optimal integration step and data presentation format. Method. At the modeling stage, to increase the efficiency, the electron Density Functional Theory was used in conjunction with the Kohn-Sham version for the stabilized jellium model taking into account the local density approximation for calculating the energy characteristics of nanoclusters. At the simulation stage, the one-electron wave function was calculated by “stitching” it from two parts at an empirically selected point with normalization before and after the procedure. A number of techniques have been developed to improve the quality of the simulation: calculating the optimal step, limiting changes in the electrostatic profile, managing the resulting data arrays, etc. For calculations on a supercomputer, the distribution between the flows was carried out. Results. At the modeling stage, economic models of the metal sphere with a vacancy in the center were developed. For the simulation stage, a method of stable two-sided calculation of the wave function using the shooting and the Numerov methods with the optimal step has been developed. The full computational scheme for the simulation is implemented in C ++ for calculation on a PC and on a supercomputer. The simulation results were compared with the \emph{ab-initio} calculation data and experimental data for Cs, Rb, K, Na, Li, Mg, and Al clusters with and without vacancies (calculation error < 15\ Conclusions. The developed computational scheme and modeling technique allow increasing the simulation efficiency and obtaining adequate energy characteristics of metal spherical nanoclusters with and without vacancies. Further research might focus on the modification of models and simulation techniques for the study of layered nanoscale systems. [ABSTRACT FROM AUTHOR]

The increasing scientific interest in Sn-based nanocomposite alloys with minor additions of oxides, metals and carbon in nanosized form is explained by the possible application of these materials as an alternative to commercial lead-free solders. As pointed out in recent literature reviews, the improved mechanical properties and reinforced microstructure of solder joints using nanocomposite Sn-Ag-Cu (SAC) alloys, compared to those without nanoinclusions, revealed new possibilities for the development of the currently used commercial lead-free solders. The main benefit of the nanosized additions is related to the suppression of the extensive growth of the Cu6Sn5 intermetallic compound (IMC) at the solder/Cu interface towards the solder side. This is achieved due to the spreading of nanoparticles over the IMC's surface, thereby suppressing the growth of Cu6Sn5 on the interface as well as in the bulk solder. In particular, the adsorbed nanoparticles on the IMC layer interface hinder the diffusion of Sn atoms from the bulk solder towards the interface and thereby suppress the IMC growth. Compared to the solid state, there is a limited number of papers dealing with experimental investigations of nanocomposite SAC solders in the liquid state after melting as well as in the semi-solid state. It has been shown that minor metal nanoadditions have an impact on the microstructure of solidified SAC solders, but practically without any significant change of the melting temperatures. The effect of small nanosized (up to 3 wt.%) nickel impurities on the electrical conductivity of Sn95.5Ag3.8Cu0.7 (SAC387) alloy has been investigated. It has been shown that the electrical conductivity gradually decreases with an increase in the impurity content of Ni. Conductivity, as a structure-sensitive transport characteristic of the liquid state of a substance, is important for modeling the processes of melting and solidification. The conductivity data provide additional information on the influence of admixtures on the structure and physicochemical properties of the metal matrix, which is important for understanding the microstructural transformations in a liquid state. Morphology of the samples was examined using REMMA-102-02 Scanning Electron Microscope- Analyzer (JCS SELMI, Sumy, Ukraine). [ABSTRACT FROM AUTHOR]

The paper presents the results of a comparative analysis of time series of Wolf numbers, total squares of spots groups, daily characteristics of the solar large-scale magnetic field (LSMF), its two components — photospheric and polar magnetic fields – with time series of the geomagnetic planetary index Ap. The cyclic changes of solar and magnetic activity and the asymmetry of magnetic field polarity reversal in two solar hemispheres were observed. The focus of this study was to determine the level of dependence of the geomagnetic activity on the dynamics of magnetic activity during the periods of the solar magnetic field polarity reversal. We used the complete homogeneous data series of magnetographic LSMF measurements (http://wso.stanford.edu), the synoptic maps of photosphere magnetic fields polarities (http://solis.nso.edu), the averaged daily squares of spots groups (http://solarscience.msfc.nasa.gov/greenwch.shtml), and the average daily values of Ap (ftp.swpc.noaa.gov/pub/warehouse). The pair of 22-23 cycles and the running 24 cycle of solar activity were investigated. We used a cumulative method of graphical representation of the studied observational data. The results are: • The north-south asymmetry of spots formation was found during 22–24 cycles. It has been established that the maxima of activity in different hemispheres are shifted by more than 1.5 years. This may be indicative of the independence of the solar cycles’ development in these hemispheres. • In the leading spots, the polarities change signs at the beginning of each cycle. At the solar poles, the magnetic field polarity reversal takes place during periods of solar activity maximum and not always at the same time. It is supposed that such an evolution of the solar magnetic field leads to the appearance of coronal holes and geomagnetic activity. • The evolution of the distribution of both solar and geomagnetic activity in the last three cycles (1986–2019) was investigated in detail. The geomagnetic disturbances are not maximal during the period of maximal spots formation, but 1–2 years later. The geomagnetic activity reflects the north-south asymmetry of the solar cycle and also the process of the solar magnetic field polarity reversal assotiated with it. [ABSTRACT FROM AUTHOR]

The origin and development of teaching and research in theoretical physics at the Lviv Polytechnic for the period from 1922 to 1933 is studied. The role of theoretical physicists of the Polytechnic in the development of physical research and training in post-war Poland and Ukraine is shown. The paper contains short biographical sketches of Professor Wojciech (Adalbert) Rubinowicz, who headed the Chair for Theoretical Physics at the Lviv Polytechnic, as well as of his students: Jan Blaton, Roman Stanisiaw Ingarden, and Wasyl (Bazyli) Milianczuk. All of them are known not only for scientific achievements, but also for organizational activities. іп particular, Jan Blaton (1907-1948) contributed to the organization of the Maria Curie-Sklodowska University in Lublin. Roman Stanislaw Ingarden (1920-2011) spend a major part of his life, from 1966 to 1991, at the Nicolaus Copernicus University in Torun; he also was a founder of the journal Reports in Mathematical Physics (in 1970). Wasyl Milianczuk (1905-1958) headed the Department for Theoretical Physics at the University of Lviv in 1945-58. He is the only link between pre- and post-WWII traditions of theoretical physics in Lviv as a whole and at the University of Lviv in particular. Prof. Milianczuk was also one of the founders of the Lviv school of spectroscopy. The bibliography of works in theoretical physics at the Lviv Polytechnic from the period of 1922-1933 is presented. The list counts thirty titles. The papers mostly concern one of Rubinowicz's primary research fields, quantum theory of radiation. More specifically, the topics include the theory of diffraction, Zeeman effect, multipole radiation, “forbidden” lines, etc. Professor Rubinowicz also authored several popular scince papers. [ABSTRACT FROM AUTHOR]

The paper describes the capabilities and the current state of the horizontal solar telescope AZU-26, as well as considers a control hardware–software complex targeting and guiding the telescope. Studies of flares in a large range of heights in the solar atmosphere have been carried out. The physical state of the photosphere before solar flares and at their initial stage has been determined on the basis of the observations. We have observed and studied some variations of chromospheric thermodynamic parameters at the initial stage of a flare and a two-ribbon flare. Nonhomogeneous semiempirical models of the flare chromosphere and surge have been built for the moments of the flare observations. Our calculations in the framework of two-component chromospheric models point to a possible existence of some details with deep heating chromospheric layers. Some twist motions were observed in the active region photosphere and chromosphere. The temporal changes of the horizontal velocities in the kernel sites and their surroundings were of a wave character and were nearly synchronous throughout the whole height of the photosphere. A detailed analysis of the motion of matter initially in the low-temperature atmospheric layers and in the flare regions on the Sun is an important factor for understanding the processes of propagation of turbulence from the region of the primary energy release as a result of magnetic reunions in flares of various types. The study of the field of velocity of the flare area by observations in a wide spectral range enables us to verify the validity of existing ideas about the mechanisms of the transfer of flare energy. [ABSTRACT FROM AUTHOR]

In this paper we consider a model that describes rumors spreading process in the social community, whose members tend to opportunistic behavior. The model is based on the assumption that information is spread by agents (the members of the community). There are four possible states for every agent. Namely, an agent can bein the neutral state, which means that the agent doesn't spread information (but potentially can do it). Being in the active state means that the agent is the source of information spreading. In the opportunistic state the agent acts to decrease the infouence of those agents which are in the active state. In the relaxation state the agent can't spread information. The agents can make transitions from one state to another. Possible transitions are from the neutral state to the active state or to the opportunistic state, from the active and opportunistic states to the relaxation state, and from the relaxation state to the neutral state. To describe how the transitions are realized, we use a system of nonlinear differential equations. The equations determine how the number of agents in different states changes depending on the current distribution of the agents by states. In particular, transition from the neutral state to the active state is realized due to passing the information from the agents in the active state to the agents in the neutral state. An additional effect of this interaction is the transition of the agents from the neutral state to the opportunistic state. Interaction of the agents in the active and opportunistic states forces the active state agents to transit to the relaxation state. It is shown that a stationary solution exists in the system, and the stationary number of agents in the active state depends nonlinearly on the parameter which characterizes the intensity of the transition from the neutral state to the active state. [ABSTRACT FROM AUTHOR]

Active galactic nuclei (AGN) are the brightest objects in the Universe and their brightness is mainly caused by accretion of m atter onto supermassive black holes (SMBH). This is the common reason of the AGN activity. However, every AGN has differences and fine features, which are the subject of an intensive investigation. The occurrence of such highly-relativistic objects as SMBH residing at the AGN core makes them an excellent laboratory for testing the fundamental physical theories. The X-rays and gamma-rays generated in a corona of an accretion disc around SMBH yield valuable information for these tests, the radiation in the range of 1-100 keV being at present the most informative source. However, there are a number of obstacles for such a study due to different physical processes that complicate the interpretation of observations in different bands of the electromagnetic radiation. In this paper, we review the current concepts concerning the structure of AGNs with a focus on the central part of these objects th at require relativistic theories for their understanding. The basic notions of the unified AGN schemes are considered; some modifications are reviewed. The paper contains the following sections. I. Introduction; II. Observational manifestations and classification of galaxies with active nuclei (II.A. Optical observations; II.B. Radio observations; II.C. X-ray data; II.D Infrared data; II.E. AGN anatomy with multywave data); III. AGN “central machine”; III.A. Black holes; III.B. Accretion disc types; III.C. Corona; III.D. AGN unified scheme); IV. Simulation X-ray AGN spectra (IV.A. The power-law contimuum and the exponential cut-off; IV.B. The absorption of X-rays; IV.C. Reflection; IV.D. Fe K a line; IV.E. Spin paradigm); V. AGN as a laboratory to test the fundamental interactions (V.A. Strong gravitational fields; V.B. Dynamic dark energy near compact astrophysical objects [ABSTRACT FROM AUTHOR]

The paper deals with an approach to the study of classical systems of interacting particles including distribution functions using random field theory and integration following the Wiener measure. For a Liouville distribution function, statistical functionality is determined for which a string of equations in the Wiener space similar in shape to the Bogoliubov chain of equations for the distribution functions in the phase space is derived. With the use of the development of statistical functionals included in the output string of equations in a row built by Wiener, in “transition” from the Wiener into the phase space, corresponding approximations for the different functions of the particles are determined, for which systems of linear differential equations are derived. The solution to the equation for the zero approximation of the one-particle distribution function represents the local equilibrium distribution, which, when t —— ^o, enters the well-known Maxwell function. All the solutions to homogeneous equations for different approximations of the one-particle distribution function if t = 0 are the same, which makes it possible to determine the unknown two-particle approximation, three-particle, etc. distribution function at t = 0. It is also indicated separately that the Bogoliubov chain of equations can produce a sequence of closed systems of linear differential equations matching the systems discussed in this paper. In the case of the statistical equilibrium all time derivatives for all approximations of the distribution function equal zero, and the time-independent functions fall into the product of two independent functions of the coordinates and impulses. The equations obtained for the distribution functions of certain approximations are easily solved. For the zero and first approximations of two-particle distribution function we obtain the known values. For the second approximation of the distribution function an expression is obtained in which one of the components is divergent, but in the combination with the following addend of the same order their sum is zero - in accordance with the general requirements for orthogonal expansions of the stochastic functional, following which the next approximation is finite. For the third approximation of this very distribution function is an expression that consists of 214 different types of addends by different amounts of the Mayer functions' products. Given the above-mentioned requirements for the orthogonal statistical functional expansion, the third approximation takes finite values too. [ABSTRACT FROM AUTHOR]

The number of exactly solvable potentials is rather limited. Therefore, much attention has been devoted to quasi exactly solvable (QES) problems for which it is possible to find exactly in an explicit form only a few energy levels and the corresponding wave functions. It was found that supersymmetric (SUSY) quantum mechanics is a powerful tool for this purpose. In our paper [V. M. Tkachuk, Phys. Lett. A 245, 177 (1998)] we proposed SUSY method for generating QES potentials with two known eigenstates. In the frame of this method the general expressions for the superpotential, the potential energy and two wavefunctions which correspond to the two energy levels were obtained. Using this method, we obtained QES potentials for which we found in the explicit form the energy levels and wave functions of the ground and first excited states. Later in [V. M. Tkachuk, J. Phys. A 34, 6339 (2001)] this method was generalized for the case of an arbitrary two energy level. In this paper the method of supersymmetric quantum mechanics has been used for discovering the quasiexactly solvable potentials for systems with position-dependent mass. We have established the conditions which provide regular potential energy in the case of a singular generating function. The examples of the quasi-exactly solvable potentials for a particle with position-dependent mass with two known eigenstates have been considered in the cases of regular and singular generating functions. We have found the exact eigenfunctions of a particle with position dependent mass which correspond to the two energy levels. [ABSTRACT FROM AUTHOR]

The spectroscopy of cold gas-dust envelopes of supernovae is the subject of this article. To define the quantitative characteristics of the matter in these envelopes, a possibility of additional sources of energy is discussed — in particular, the intense, diffusely distributed flows of high-energy positrons formed by the recently discovered chain of radioactive decays: 4422Ti 85 y −−→ 4421Sc 6 h −→ 4420Ca. The quantitative characteristics of radiation distribution function S(E, r) and electron distribution function F(E, r) are obtained for certain rarefied layers of the supernova remnant SN1987A. An additional feature of the kinetic ensemble of the envelope’s gas with the mentioned radioactive decay is the presence of the recoil nuclei of the final elements of this decay’s chain. In the case under consideration, these are the nuclei of 4420CaII. The paper notes that the motion of recoil nuclei in a rarefied supernova gas at a sufficiently high kinetic energy accumulated by radioactive decay determines that the recoil nuclei exist only in an ionized state, and the remaining nuclei, after hydrogen recombination, — in a neutral state. In the discussed case, 4420CaII can be observed only in an ionized state, and 4420CaII — only in a neutral state. This remark can be applied to the recoil nuclei of other elements formed at earlier times during the hydrogen recombination. It is shown that this method is suitable for isotopic separation of the final elements of radioactive decay chains occurring in young supernova envelopes. The presence of a nonthermal component in the obtained distributions of S(E, r) and F(E, r) causes an additional IR emission of the dust formed during the expansion of a supernova envelope in the modern epoch of observations. The presence of spectral lines at the moment of the Hubble telescope observation allowed us to conclude that the existence of the numerous observed spectral lines in the optical, UV, and near-infrared regions of the spectrum requires the presence of the astronomical silicates with extensive passbands extending over these spectral intervals in the observed dust shells. The presence of graphite dust in these bunches excludes the existence of the observed optical component of the spectrum and requires its presence in separate shell structures enriched with C–N–O elements. However, in this case, the presence of decaying 4422TiII isotopes which form the fast positrons is unlikely. The graphite particles, as well as H2 molecules, are influenced by positrons only when the density of the shell allows them to reach its outer layers. In this case, the number of collisions with atoms should not exceed several thousands. It is necessary to decelerate them before the complete annihilation with atomic electrons of the shell’s atoms and molecules. [ABSTRACT FROM AUTHOR]

We present a brief essay about the statistical physics of complex systems - a research direction that now acquires features of a well established field of science with its object of study, conceptual background, and methods of analysis. A complex system consists of many interacting parts (agents) and manifests collective behaviour nontrivially following from the behaviour of its individual components. Examples of complex systems are found in condensed matter, ecological and biological systems, human society, stock markets and economy. The concept of a complex system refers to many traditional disciplines of science and forms a new, inter-disciplinary branch of knowledge. Peculiar features of complex systems are self-organization, emergence of new functionalities, adaptive nature of interactions, high sensitivity to small changes in the initial conditions, governing power laws ("fat-tailed" distributions). In our paper, we concentrate on applying methods and concepts of statistical physics in a complex system analysis. We discuss how such approach allows for conceptual understanding and interpretation of a wide range of phenomena in various systems, not necessarily of physical origin. Together with the general description of the properties of complex systems, we give a brief overview of some studies performed in this field at the Institute for Condensed Matter Physics of the NAS of Ukraine (Lviv, Ukraine). In particular, these studies cover critical behaviour of complex magnets, scaling behaviour of complex polymer macromolecules, phase transition of spin system on complex networks, sociophysical approaches to studying human activities, scientometrics. [ABSTRACT FROM AUTHOR]

The paper is devoted to the study of X-ray luminescence spectra, the scintillation light output and the decay time characterisation of undoped ZnTe at low temperatures down to 6 K. Also, the photoconductivity spectrum in a visible region has been investigated. Due to significant thermal quenching, the scintillations at α-particle excitation were detected in the sample only below T = 150 K. The emission of the crystal is attributed to the radioactive recombination of the holes trapped by Zn vacancies and electrons captured at the shallow levels of impurities or defects. The scintillation efficiency increased with further cooling. It has been found that at α-particle excitation undoped ZnTe exhibits a fairly competitive light output equal to 117 ± 20% of CaWO4 reference scintillator. This finding underpins potential applications of ZnTe as a scintillation detector in the cryogenic experiments, particularly for the cryogenic search for neutrinoless double beta decay of 130Te. It has been also found that ZnTe will be attractive as a conventional scintillation detector at the temperature of liquid nitrogen (T = 77 K). At this temperature, the scintillator exhibits a reasonably short decay time and a sufficient scintillation response to particle excitation. A practical implementation of this idea poses no real technical challenge since photomultipliers and Si-based photodetectors are proven to operate reliably and efficiently at this temperature. [ABSTRACT FROM AUTHOR]

The basic analytical forms of the deuteron wave function (DWF) in a coordinate representation have been reviewed. The asymptotic behaviour of DWF near the origin of coordinates has been analyzed. New analytical forms of DWF as a product of the exponential function rn and the sum of the exponential terms Ai exp(−air3) are applied for the calculation of the polarization characteristics of the deuteron. Numerical calculations have been done for realistic phenomenological potential of Nijmegen groups, Reid93. In the paper, the results of the angular asymmetry for deuteron vector t10, t11 and tensor t20, t21, t22 polarizations are described. Along with the angular asymmetry, the momentum asymmetry for deuteron vector t1i polarizations is described too. The influence of DWF approximation in a coordinate representation on the subsequent results of the calculations of the tensor polarization t20 is investigated. A comparison of values t20 is made at θ = 70◦ if to apply four different DWF approximations to the same NN-potential Reid93. When the received theoretical values t20 are compared with the experimental data of world collaborations and reviews, a good coordination for the area of values momentum p = 1 − 4 fm−1 is observed. Using the method of invariant amplitude, spin observables in backward elastic dp-scattering-tensor analyzing power T20 and polarization transfer κ0 have been calculated. The values of κ0 and correlation κ0 − T20 are compared with experimental data. In a wide range of momentums p and scattering angles θ, the asymmetry for the tensor analyzing power T20 and T22 has been presented, which characterizes the photoproduction of negative π-meson from deuteron in reaction γ(d, π−)pp. A symmetry of values T20 and T22 concerning a 90◦ angle is observed. The ratio R for the vector Px and tensor Pxz polarizations is characterized by angular asymmetry. So, along with the “Ay puzzle”, it is reasonable to carry out further theoretical and experimental research into other polarization characteristics of the processes with deutron participation, for which there is both angular and momentum asymmetry. The obtained results of the deuteron vector and tensor polarizations tij (p) give some information about the electromagnetic structure of the deuteron and the differential cross section of double scattering. [ABSTRACT FROM AUTHOR]

A case study of the “journalometric” analysis, i.e. the quantitative analysis of the publication data in a scientific journal, is presented in this paper. Different kinds of data can be used to describe various aspects of editorial work as well as to characterize the publication set. We consider the so-called internal and external data: the first data set includes all bibliographic data and information about the timing of editorial processes, while as the second data set, we use the statistics of citations obtained from outside sources (Web of Science and Scopus in our case). The methods of complex network theory, descriptive statistics, and regression analysis are useful tools to process such data. Coauthorship connections on the level of separate authors, countries, cities, and scientific topics are presented in the form of networks — which is convenient for quantitative analysis and for visualization. The shape of citation distributions is discussed separately. All these results and findings are naturally framed by a short story about the history of the Journal of Physical Studies, an open access journal for the general field of physics published in Ukraine, which issued its 20th volume in 2016. The results of the case study presented here illustrate the combined approach to analyzing a scientific journal. It can be useful both for assessing the role of a journal as a whole, and for developing editorial policy for the future. A similar approach can be applied to analyze a group of journals, e.g. to describe the state of national scientific periodicals. [ABSTRACT FROM AUTHOR]

In the paper, we consider a two-dimensional system with radial symmetry that contains bacteria and an attractant. It is known that the bacteria receptors can interact with the attractant. As a result of this interaction, the bacteria move towards the highest concentration of the attractant. The general effect is that the concentration of the bacteria increases as the attractant concentration increases. On the other hand, if the total amount of the attractant is high, then the bacteria’s reaction to the attractant gradient is not so strong. So by changing the attractant distribution in the system one can change the bacteria distribution, and this dependence is nonlinear. In our model, the attractant is injected into the system within its central area. We investigate the bacteria distribution due to chemotaxis under a stationary nonhomogeneous distribution of the attractant. The chemotaxis sensitivity function is used as the characteristic of the nonhomogeneity of the bacteria distribution. We propose a methodology for calculating the chemotaxis sensitivity function for a two-dimensional system with radial symmetry. We have received an analytical expression of the chemotaxis sensitivity function, and we have also calculated how it depends on the attractant concentration at the boundary region. It has been shown that this dependence has a bell-shaped maximum, as is the case for a one-dimensional system. The position and the value of the maximum have also been found. [ABSTRACT FROM AUTHOR]

The paper is devoted to the electron properties of the transition metal films of the islands structure. The main research methods are theoretical calculations based on the density functional theory and the ab initio pseudopotential method. Using the author's software, the spatial distribution of valence electron density, the distribution of electron states density, the bandgap, the Coulomb potential along the transition metal (Ni0,8Fe0.2, Ni, Cu, Pt) films with islands structure were calculated. Our calculation showed the presence of the size effects that manifest in the oscillation of a dependence of the bandgap on the distance between the islands. The range of the gap oscillations of the Ni0.8Fe0.2, Ni, Cu island films reaches about 10 eV/atom, and the gap oscillations of the Pt-film does not exceed 0.6 eV/atom. It is important that the bandgap of the continuous metal films of variable thickness are small. We have discussed the features of the spatial distribution of the valence electrons of the islands films has been revealing a deviation from the typical metal distribution. The potentials which were obtained along the vector through the islands had non-zero values in the area between the islands that confirm their interaction with each other; therefore, the island film is an integral object. Since the self-consistent electron density was analyzed, it can be assumed that the interaction between the atoms of the neighboring islands was of the Coulomb and quantum (exchange-correlation) type. [ABSTRACT FROM AUTHOR]

In this paper the high-resistance samples of p-Si (p0 = 6.4 • 1012 см-3) and n-Si (no = 2.1 • 1012 см-3), grown by the floating zone melting method and irradiated with different fluences of fast neutrons at 320 K, were investigated. The irradiation was carried out by fluences of (3.85 • 1012 + 3 • 1013) nocm-2 in a horizontal channel of the water-cooled nuclear reactor WWR-M of the Institute for Nuclear Research of National Academy of Sciences of Ukraine. The flux of fast neutrons was defined by the 32 S threshold detector (the threshold energy is equal to E = 0.95 MeV) with an accuracy of 10 %. Conductivity and Hall coefficient measurements were carried out by the Van der Pauw compensation method on samples of the 10 x 10 x 1 mm size with the accuracy of 3 %. The contacts were created by rubbing aluminium into the polished silicon surface. In silicon, doped with donors or acceptors, the temperature dependence of electron concentration was described. This temperature dependence is associated with the recharging of divacancy at the configurational reconstruction from one configuration with a greater distortion in another configuration with a smaller distortion, and vice versa. It was found that during the configurational reconstruction of divacancy the appearance of the generalized levels of divacancy was observed: Ec — 0.23 eV (V2~) in n-Si and Ev +0.283 eV (V+) in p-Si. It is shown that the concentrations of the V2- and V+ divacancies with the respective generalized levels are determined not only by the type of nuclear radiation, but also depend on the introduction of the point defects of the interstitial type, which create an additional deformation of the silicon lattice. The additional deformation of lattice leads to a decrease of probability of the configurational reconstruction of divacancies and, consequently, to a decrease in the concentrations of generalized levels of the double-negatively and positively charged divacancies. [ABSTRACT FROM AUTHOR]

Universality is one of the essential concepts in statistical physics. It means that the typical behaviour of a macroscopic system consisting of many interacting agents is independent of the system's structural details. This concept gains more and more popularity, not only in purely physical problems, but also in general scientific and cultural contexts. In this paper the concepts and methods of statistical physics and complex networks science are used for the detection and quantitative description of universal properties of social networks of Bylyny characters. Bylyny are heroic epics of eastern Slavs. We consider the epics covering the heyday of the Kyivan Rus (end of the tenth century to the middle of the twelfth century). By this analysis, we continue a series of works initiated in [P. Mac Carron, R. Kenna, EPL 99, 28002 (2012); P. Mac Carron, R. Kenna, Eur. Phys. J. B 86, 407 (2013)], where such quantitative methods were used to analyse several prominent European epics. The method we are using allows obtaining additional reasoning on some hypotheses about the origin of Bylyny characters and their connection to the historical figures. By comparing our results with those previously obtained, one can detect common (universal) characteristics of various epic narratives. These properties remain unchanged in time and are shared by different cultures. Thus, epics have universal properties, allowing for an additional classification based on their quantitative analysis. [ABSTRACT FROM AUTHOR]

The local field approach and kinetic equation method is applied to calculate the line broadening of the surface plasmon resonance (SPR) in a spheroidal metal nanoparticle (MN) embedded in any dielectric media. Usually, both the surface and the radiative damping mechanisms play an important role in the plasmon decay. In the MNs of a smaller radii, the penetration depth of the plasmon field reduces and becomes more localized near the surface. As a result, the bulk-induced loss processes play only a minor role and the electronic excitations generated by the surface potential dominate. The radiative damping of the SPR is an important parameter since it would help to analyze the specificity of the transformation of the collective electron oscillation energy into the optical far field. In the former similar works, it was dropped from the account the fact that the role of an external electric field can play the inner electric field in MN. The purpose of this paper is to calculate the radiative damping of the SPR under the effect of inner electric field, for the case when the mean free path of the electrons is larger than the particle size and their scattering on the particle surface plays an important role. In presented work the radiative damping of the SPR as a function of the particle radius, shape, dielectric constant of the surrounding medium, and the light frequency is studied in detail. It is found that the radiative damping grows quadratically with the particle radius and oscillates with altering both the particle size and the dielectric constant of a surrounding medium. Much attention is paid to the electron surface-scattering contribution to the plasmon decay. All calculations of the radiative damping are illustrated by examples on the Au and Na nanoparticles. [ABSTRACT FROM AUTHOR]

We study a space in which spatial coordinates do not commute. We consider a noncommutative space of the canonical type characterised by the constant antisymmetric matrix of noncommutativity. Length, area, and volume are limited below in this space. The corresponding minimal values are determined by the elements of the matrix of noncommutativity. We examine the minimal length, area, and volume in a noncommutative space of the canonical type with the preserved rotational symmetry which has been proposed in our previous paper [Kh. P. Gnatenko, V. M. Tkachuk, Phys. Lett. A 378, 3509 (2014)]. The corresponding rotationally invariant noncommutative algebra is constructed with the help of the generalization of the parameter of noncommutativity to a tensor. The latter is constructed with the help of additional coordinates that are governed by a rotationally symmetric system. It is shown that in the rotationally invariant noncommutative space there is a minimal length which is determined by the mean value of the tensor of noncommutativity. On the contrast to the canonical version of noncommutativity in the rotationally invariant noncommutative space the area and volume are not constrained. [ABSTRACT FROM AUTHOR]

For the calculation of single-channel nucleon-nucleon scattering the phase-functions method has been proposed. Using the phase-functions method the following phase shifts of a nucleon-nucleon scattering are calculated numerically: nn (1So-, 3Po-, 3Pi-, 1D2-state), pp (1So-, 3Po-, 3Pi-, 1D2-state) and пр (1So-, 1Pi-, 3Po-, 3Pi-, 3D2-, 3D2-state). The calculations have been performed using realistic nucleon-nucleon potentials Nijmegen groups (Nijml, Nijmll and Nijm93). The feasibility of the fourth-order Runge-Kutta method for numerical calculations of phase shifts was explained. When choosing the step of the optimized calculations phase shifts of up to 0.01 were received. The obtained phase shifts are in good agreement with the results obtained in the framework of other methods. They are also in good agreement with the results of the original paper for the same potential. The deviation is not more than 2%. We also compared the results of calculations of the phase shift under the phase-functions method with the phase shift for other potential models (Argonne v18 and CD-Bonn) and for the partial wave analysis. The deviation between these data is up to 5%. Using the obtained phase shifts we have calculated the full cross-section and the partial scattering amplitudes. These results are in good agreement with those obtained by using known phases published in the literature. 4201 [ABSTRACT FROM AUTHOR]

Accelerated nucleation in response to laser or dc electric fields has been observed in a number of systems. The phenomenon is typically attributed to the lowering of the nucleation barrier by the field-induced polarization of the new phase particle. This paper introduces the concept of plasmonic mediated nucleation. The underlying idea is that the nucleated particle provides a narrow resonance and phase of plasmonic oscillations that maximize its polarizability in the external electromagnetic field; that makes such particles energetically more favorable and lowers their nucleation barriers. As a result, an ac field will favor the nucleation of a particular geometry, such that the plasmonic frequency of the particle is in resonance with the field frequency. The nucleation of both the pancake and needle shaped nuclei for both cases of linearly and circularly polarized light has been considered. We predict the electromagnetic field driven nucleation of nanoparticles that provide plasmonic oscillations in resonance with the field frequency. The oscillations assume a phase that maximizes the particle polarization and energy gain due to nucleation. We derive closed-form expressions for the corresponding nucleation barrier and particle shape vs field frequency and strength, electron plasma frequency in metal, and the host dielectric permittivity. We show that the plasmonic polarization allows for the nucleation of particles that would not be stable in zero field. [ABSTRACT FROM AUTHOR]

The level of Solar activity during long-term and deep minimum of 23rd and 24th cycles with its influence upon the terrestrial climatic system were explored according to the observational data of Astronomical Observatoty of the Ivan Franko national University of Lviv, the SORCE (Solar Radiation and Climate Experiment) space apparatus, several British climatic research centres and world INTERNET data base (ftp://ftp.ngdc.noaa.gov/SPP/SOLAR_DATA) about Solar activity. Typical peculiarities of the minimum of cycles 23/24 were studied at this paper. The transition period from January 2008 to July 2009 was characterized by first-sunspot activity reached the lowest values during the last 100 years; secondly the substantial asymmetry of the development of Solar activity at different hemispheres was discovered; and thirdly one may observe violations of synchronous changes of 11-year cycle and Tglob. prior to 1998. The authors were find out two opposite acting factors after comparation of the data by British climatic centres about low level of Solar activity, the change of global temperature (Tglob.) and substantial depletion of stratospheric ozone layer during the minimum of cycles 23/24. The substantially exhausted stratospheric ozone layer caused the aggrandisment of Solar energy which reached the terrestrial ground and so the low level of Solar activity was compensated. Therefore Tglob. remained sufficiently stable. [ABSTRACT FROM AUTHOR]

This paper presents a study of X-ray Abell 13 (kT = 5.76 ± 0.15 keV) cluster located at the distance of 400 Mpc (z = 0.0943) from us. The data on cluster was obtained from Chandra X-ray Observatory. We used numerical simulations and the hydrostatic equilibrium condition on the intracluster gas for determining the total mass of the cluster. We used the Navarro-Frenk-White model and spherically symmetry assumption for modeling the density profile of a dark matter, and also the &bgr;-model to study a central region of the cluster in detail. As a result, the following parameters of the &bgr;-model were obtained after getting fit to the surface brightness. &bgr; = 0.87 ± 0.07 and r0 = 134 ± 22 kpc. We used the DSDEPROJ method of deprojection for getting more accurate parameters to determine the density profile and mass of Abell 13. Thus, the total mass of the cluster was obtained as M200 = 4.69+0.51 -0.44 1014M⊙ for the radius R200 = 1.51+0.41 -0.33 Mpc. The fraction of a dark matter in the total mass is ∼ 90%, while the gas is ∼ 10%. We did not take into account the galactic component, so, the "total" mass is the sum of masses of a dark matter and intercluster gas. [ABSTRACT FROM AUTHOR]