The cross sections of partial photoneutron reactions for 139La and 145,148Nd free from the shortcomings of the different methods for determination of neutron multiplicity used on the beams of quasimonoenergetic annihilation photons and bremsstrahlung were evaluated. The new data for (γ, 1n), (γ, 2n) and (γ, 3n) reactions cross sections were obtained using the experimental–theoretical method of evaluating the cross sections of the partial reactions, satisfying the reliability criteria imposed. It was shown that noticeable deviations of the experimental cross sections from the evaluated values result from the unreliable sorting of neutrons between the channels with multiplicities 1, 2 and 3.
Show AbstractThe neutron detector on the basis of ZnS(Ag){$+^6$LiF} scintillator which can be used for the monitoring of the level of background radioactivity near nuclear objects is described. The detailed description of the created model of the detector in the software package Geant4 is given. The model takes into account the real dimensions of the detector and its composition. Optical properties of substances are described. The necessary processes are inserted. Response of the detector for muons and neutrons was simulated. In the case of neutrons, response simulation used alpha and tritium particles with energies corresponding to the lithium decay after neutron capture. The processing of the results shows that the average number of photons counted in the result of neutron capture is about nine times more than the number of photons emitted after passing of muons through the scintillator, in addition, the shape of the signals differs. Further, using the SERPENT code, it is planned to take into account all physical processes of propagation and interaction of neutrons with matter, as well as to take into account the neutron spectrum possible for a non-emergency situation at the nuclear setup.
Show AbstractAngular momentum dependences of the parity splitting and eletric dipole transitons in the alternating parity bands of heavy nuclei have been analyzed. It is shown that these dependences can be treated in a universal way with use of a single parameter of critical angular momentum, which characterizes phase transition from octupole vibrations to the stable octupole deformation. Using the simple model of axially-symmetric reflection-asymmetric mode, the analytical expression for the partiy splitting and electic dipole transitional moment have been obtained. The results obtained are compared with the experimental data for various isotopes of Ra, Th, U, and Pu.
Show AbstractThis study illustrates the impact of 1 MeV electrons at different doses on bacteria quantity in chilled trout. It was determined that the irradiation of fish led to a significant decrease in bacteria quantity in it. Some structure changes in the product were determined after the treatment of irradiation in doses from 2 kGy to 21 kGy
Show AbstractA model of spatio-temporal self-organization of urban ecosystems as a superposition of conjugated active media, taking into account the nonuniformity of anthropogenic and natural factors. The high rate of growth of population and density due to the concentration of residential, industrial, commercial and other objects, as well as communication media, leads to a reduction of areas of natural biocenoses, autocatalysis of the development of anthropogenic processes and, consequently, an increase in the nonlinearity of system-wide processes. The model is based on the FitzHugh-Nagumo equation, modified by the authors. The validity of this type of application is determined by the relative simplicity of the system analysis of the two equations of the «activator - inhibitor» type. The conditions for the formation of an excitable / unexcited state of the active medium depending on the population density and the kinetic parameters of the system, as well as the formation of barrier zones such as tunneling and locking in the course of the structure formation of urban ecosystems are obtained. Analytic and numerical investigation of stationary solutions of the system is carried out.The dimensionless model is confirmed by the dynamics of population and population density and spatial data development of Moscow (Kuntsevo District) from 1952 to 1968. The model with spatial inhomogeneities allows to reveal threshold values of control parameters and to consider the basic principles of development of autowave processes forming the structure of urboecosystems. Keywords: urban ecosystem, self-organization, active medium, autowaves, heterogeneous structures
Show AbstractThe concentration dependences of self-diffusion coefficient of various proteins: fibrinogen, trypsin, α-chymotrypsin and αS-casein were studied by means of the pulse field gradient nuclear magnetic resonance. The experimental data was analyzed in a view of the Vink’s phenomenological approach based on the frictional formalism of non-equilibrium thermodynamics. The obtained results indicate that the phenomenological approach is universal and provides an adequate description of the experimental data for proteins of different structure and shape in a wide concentration range. With the help of Vink’s approach the diffusion mobility of proteins was characterized. The concentration was determined, when the αS-casein oligomerization appears.
Show AbstractIn this study, a significant effect of fluid injection on the b-value and acoustic activity was found from the results of a laboratory study of the destruction processes caused by filtration processes. The migration of sources of acoustic emission from the side through which water was injected along the sample axis was detected. The difference in the rates of fluid diffusion into dry and saturated samples was confirmed. The used method of thermal stimulation of cracking allowed to increase the porosity and permeability of rock samples by almost an order of magnitude.
Show AbstractThe main calculated parameters in the processing of full waveform acoustic data are the propagation velocities of elastic waves. The determination of velocities is based on the arrival times of these waves. At the same time, the geological environment also affects the amplitude-frequency response (AFR) of elastic waves. In general, wave attenuation is caused by three processes: geometric divergence, scattering by inhomogeneities, and inelastic absorption. It is known that oil and gas saturated media have a larger absorption coefficient in comparison with water-saturated and dry media. However, usually amplitudes are affected by random noise and interference of waves, as well as by noise caused by heterogeneity of source and receiver conditions (for example, by changing the borehole diameter and transmission coefficient, by the presence of diffraction points and clay crusts). Therefore, old three-element acoustic logging devices did not allow to reliably iterpret information from AFR of waves and the standard software did not have the means of its calculation. Modern multi-element devices, as a rule, have several sources and a lot of receivers. That provides favorable conditions for the application of already existing methods of calculating the effective damping coefficient, and the development of new approaches. In this paper we consider a method for calculating the coefficient of effective damping which is the sum of inelastic absorption and scattering by inhomogeneities. The method is based on factorial decomposition of the wavefield and it excludes the effect of inhomogeneity of the source and receiver conditions.
Show AbstractThis work describes of ionospheric effects from the data of global navigation satellite systems of a number of solar flares of different power classes (X-, M-, C-class) during 2014-2017. Our results demonstrate that the algorithm of averaging the derivative of the variations of the total electron content for all stations on the illuminated side of the Earth can exactly detect of X-сlass flares and with sufficient accuracy for practice detect of M-class flares in the automatic mode (the «signal skip» error is approximately 2.76%). Also shown that in some cases the variability of the ionospheric response is a consequence of the difference in the dynamics of solar radiation in the X-ray and ultraviolet frequency ranges.
Show AbstractThe flux of muons generated in the atmosphere is sensitive to changes of its basic thermodynamic parameters along the particle trajectory. This dependence is used for the muon diagnostics of the atmosphere. It can be used to trace the dynamics of such events as thunderstorms. In this work the search of thunderstorm-caused disturbances of the muon flux registered by the muon hodoscope URAGAN was conducted by an automatic method of finding of the significant deviations of the current values of the muon counting rate ($I_\text{sum}$) and local anisotropy parameters ($r_\text{south}$, $r_\text{east}$, $r_\text{z}$) from their moving average. The dates selected by this way were compared with the thunderstorm observation dates from the data of three independent meteorological stations ``Domodedovo'', ``VDNKh'' and ``Balchug'' as well as with the data of the meteorological station located in the Experimental Complex NEVOD. The analysis of the obtained data showed that the characteristic events for a thunderstorm are single deviations in the considered parameters, which usually occur several times during a thunderstorm. Also, during a thunderstorm, periodic perturbations with periods in the range from one to five hours are found in the characteristics of the muon flux.
Show AbstractThe paper presents the results of studying the influence of stresses on the permeability of different types of reservoir rocks in oil and gas fields. The investigations were carried out at the Triaxial Independent Load Testing Facility of the Institute of Problems in Mechanics of the Russian Academy of Sciences. It is established that the character of the dependence of the permeability on the acting stresses for different rocks can be significantly different. The results of the studies confirm the classification of rocks proposed earlier on their reaction to the change in the stress-strain state. The results of independent studies of recent years and their analysis with application of the proposed classification to the test results presented in the works are given. They also confirm the validity of the proposed classification.
Show AbstractBased on the results of instrumental observations of microimpulsions of atmospheric pressure, the main waves of the luni-solar tide in the Earth's atmosphere are identifed. The registration of micropulsations is obtained in the range from 0.1 MHz to 10 Hz in the Geophysical observatory «Mikhnevo» of Institute of Geosphere Dynamics of Russian Academy of Sciences located in the Moscow region, situated outside of the zone of the megapolis influence. The data for period 2008 - 2016 were involved. An estimate of the spectral characteristics of microimpulsions was carried out using the maximum entropy method. In order to increase the level of discrimination related to the frequencies of tidal waves, the adaptive rejection filtering method was applied. It is shown that the spectral amplitudes with frequencies that coincide with the frequencies of the tidal waves change with time with a periodicity of about 29 days. The characteristics of modulation of the solar elliptic wave $S_1$ and the main solar wave $S_2$ by periods of 13.66, 27.55 days are obtained; as well as $\sim$ 0.3, 0.5 and 1 year.
Show AbstractThe paper presents an method to solving the problem of reading road signs on images obtained under uncontrolled registration conditions. The registration conditions are taken into account in the morphological analysis applied in this work. This task is divided into the localization of traffic signs of certain colors and shapes, and reading the candidate for road signs.
Show AbstractThe paper deals with the construction of exact singular solutions of the Kuznetsov equation, better known as the Khokhlov-Zabolotskaya-Kuznetsov equation (KZK). This equation is a third-order partial differential equation and describes the propagation of a bounded sound beam in a nonlinear medium with dissipation. To construct exact solutions, the methods of the modern theory of symmetries of differential equations and the theory of singular solutions are used. Also, in this paper, some solutions are visualized, in particular, a solution that corresponds to the effect of focusing the sound beam.
Show AbstractIt follows from the theory of measuring-computing systems that the requirements for a measuring transducer (MT) that forms measurement result during interaction with the measured object in order to obtain maximal interpretation accuracy significantly differ depending on how it is going to function — by itself or as a part of a measuring-computing transducer (MCT). In the second case, maximal interpretation accuracy has to be provided by the MCT that is considered to be a measuring device of the same purpose as the "perfect" device for the researcher. As a rule, an exact mathematical MT model and, hence, the algorithm realized by the computing transducer (CT) that provides maximal accuracy of MCT as a measuring device, are not known to the researcher, but he can perform test measurements of known objects. The aim of this article is to synthesize using test measurements both the response of a MT with unknown model and the optimal interpretation of the measurement result, i.e., the output signal of the MCT.
Show AbstractIn the present work, the crystalline phase nucleation and growth processes in a metallic melt are investigated at different supercooling values. We show that both at small and at extremely deep supercooling levels, the homogeneous nucleation scenario is realized at the initial stage of phase transition of the system. We found that the nucleus critical size depends slightly on the supercooling level of the system: in the considered temperature range the nucleus critical size decreases by a few tens particles at significant increasing of supercooling level. The maximal nucleation rate is achieved at moderate supercooling, which corresponds to temperature range located near the glass transition temperature of the system.
Show AbstractPhenoMaster is a unique modular autonomic platform. It provides scientists from different research areas modern technology for fully automated and synchronized metabolic, behavioral and physiological monitoring: indirect gas calorimetry, food and fluid intake, locomotor activity, learning, memory, etc. Data recording can be performed for any given time interval, for example, every second and for any given period. The output is a huge amount of data, which is very difficult to analyze and interpret. This work is devoted to the solution of this problem. Data analysis was carried out on the basis of a comprehensive study the effect of oral injection of biologically active additives based on silver nanoparticles on the behavioral, cognitive and physiological functions of mammals. Physiological features of animals were recorded in the system of automatic monitoring PhenoMaster: body weight, the amount of feed and liquid consumed, motor activity. To analyze the obtained data, a unique method was developed. It takes into account measurement errors, time averaging and ensemble averaging, as well as features of living organisms to obtain relevant results. The obtained data were analyzed for changes in the amount of consumed water and food, changes in body weight, disorders of circadian rhythms, changes in motor activity and its preferences. The analysis was performed using the SPSS Statistics package based on the Mann-Whitney u test for independent samples.
Show AbstractGold nanoparticles (GNPs) are known for their ability to enhance the biological effect of ionizing radiation. The GNP localization relative to critical cellular targets, especially to nuclear DNA, in this application is decisive. Recent research has shown that the spatial distribution of GNPs in the particles of DNA liquid-crystalline dispersion modeling the density of chromatin packaging in vivo is determined by GNPs` size. In this paper, the absorbed dose of photon radiation with energy from 20 to 600 keV and dose enhancement factors (DEF) for two models of GNPs distribution relative to the particle of DNA liquid-crystalline dispersion were calculated by Monte Carlo method in the Geant4 code. GNPs` concentration were 1%, 2% and 4% of the DNA mass. The highest DEF from 13.2 to 1.1, depending on the photon energy, was obtained for the model №1. For Model №2, DEF depended little on the GNPs` size. The DEF values in model №1 were from 1.1 to 7.6 times more than in model №2 depending on photon energy. These results indicate the importance of the GNPs spatial distribution for the enhancement of absorbed dose in critical targets, especially in cell nucleus.
Show AbstractNumerical modeling of the aortic and pulmonary component of the second tone signal and application of the Wigner — Ville transform for processing the obtained model signal for the purpose of component separation are performed. If the components can be separated in the time-frequency domain with use of Wigner-Ville transform, it is possible to restore their temporal profile by overlaying the corresponding mask and performing the inverse transformation. It is shown that the components of the second tone can be separated with a time delay exceeding 40 ms. Signals of the second tone of the human heart were recorded with a stethoscope connected to a microphone. Acoustic signals were filtered by a hardware filter with a tunable cutoff frequency in the range of 31-125 Hz and processed using Wigner — Ville transform. In norm, when the delay between aortic and pulmonary components does not exceed 30 ms, their separation by the proposed method is impossible.
Show AbstractThis work is devoted to modelling and development of electric current sources for implantable devices based on yet unused physical principles. Moreover, in this article we present an overview and comparative analysis of characteristics of different implant energy supply technologies which are applied in practice and exist in theory.
Show AbstractIn this work, the spectra of the direct binary modulation and the orthogonal multi-frequency modulation are calculated. It is shown that binary sequence transmission by the method of multi-frequency modulation reduces the out-of-band radiation. Thus, decreases the inter-symbol interference as well as the transition noise in multi-channel systems.
Show AbstractPerovskite MAPbI3 is considered to be extremely promising for various photovoltaic applications. In connection with such an application, it is important to investigate the transfer of charge carriers in the material used. In this study, using impedance spectroscopy, we determined that the conductivity in polycrystalline MAPbI3 with a grain size of 0.1-1 μm is given by the hopping mechanism of charge carrier transfer. Also, based on the hodograph of the perovskite samples, we proposed an equivalent circuit for replacing the samples studied.
Show AbstractSilicon nanoparticles were produced by sequential use of techniques of electrochemical etching and picosecond laser ablation in distilled water, ethanol and liquid nitrogen. Ensembles of the nanoparticles formed in two last cases exhibit effective photoluminescence with a peak get into the diagnostic window of biotissue transparency (700–1300 nm). Optical characteristics of the obtained silicon nanoparticle suspensions were studied by the spectrophotometry technique. It was shown that the examined suspensions possess the light scattering coefficients which are sufficient for their use as contrast agents in the optical coherence tomography.
Show AbstractWe show that for a non-minimally coupled theory containing derivatives of the scalar field (Sushkov's action) in Palatini formalism the connection turns out to be metrically associated with the "second" metric, which is non-conformally expressed through the physical metric. We obtain that in the first order approximation in a weak scalar field regime the effective Energy-momentum tensors coincide in the 1st and 2nd order formalisms, but in general they can differ and higher derivatives appear in the equations of motion. We also prove that in this theory, as in the non-minimally coupled theory $R\phi^{2}$, as well as for theories $f(R)$, torsion can be reduced to a gauge transformation with respect to which the action is invariant. We also investigated the Einstein-Chern-Simons action and determined that in the absence of nonmetricity it reduces to the Einstein-Hilbert action with the minimally coupled scalar field.
Show AbstractIn this paper phase phenomena in the three-dimensional Ising gauge model were studied. Using the Monte Carlo simulation method, it was shown that the model possesses a phase transition. To determine the critical temperature of the model several order parameters were considered: plaque magnetization, Wilson loops and the mass of the lattice defect (vacancy). Considering the Wilson loops of area 2 of different spatial forms, we have found the energy difference between them in the vicinity of the phase transition. It was also shown that the mass of the defect has a peak near the phase transition and that this peak's position tends to the critical point with increasing lattice volume.
Show AbstractIn the present work we studied the behavior of the magnetic field calculated in the paraboloid model of the Jovian magnetosphere, for different values of the parameters. The most significant parameters of the model were found and their effect on the model magnetic field along the second orbital trajectory of the Juno spacecraft was studied. The influence of the magnetodisc model on the position of the spacecraft trajectory projection on the ionosphere is considered.
Show AbstractIn recent years, much attention has been paid to the study of magnetoelectric (ME) effects in solids that was caused by the possibility of their practical applications. In most of natural crystals, ME effects are small in magnitude and are observed, as a rule, at low temperatures or in large magnetic fields. To date, most of the experimental work is devoted to a direct magnetoelectric effect. However, the study of the inverse magnetoelectric effect also deserves attention. The ME effect can be increased by creating composite structures. This paper is devoted to the study of the reverse ME effect in a two-layer composite sample consisting of a piezoelectric plate Pb(Zr, Ti) O3 and an amorphous FeSiBNbCu ferromagnetic ribbon. It was found that the ME effect depends on the magnitude of the magnetization reversal field, H, the electric voltage, U, and also on their mutual orientations.
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