Experimental studies and theoretical calculations of photonuclear reactions on a natural mixture of palladium isotopes have been performed. The yields of photonuclear reactions on a natural mixture of Pd isotopes were measured on a bremsstrahlung with a maximum energy of 55 MeV. The results are compared with the results of calculations by a combined model of photonuclear reactions.
Show AbstractThis work considers an optical system that operates by both quadrupole transition and evanescent surface plasmons waves. The surface plasmons waves is generated by the total internal reflection, and its intensity is distributed in the vicinity of the surface. The theory of such an optical system is constructed, assuming the quadrupole transition is only allowed, and then the quadrupole optical forces and the ensuing reflection of Cesium atoms is shown. The emphasis here is on the role of the metallic capping layer with a finite thickness and a finite plasma frequency on the evaluation of atomic reflection processes. A desirable enhancement of the evanescent plasmons waves magnitude is obtained. At the same time, a significant decrease in the atom-surface attraction, which is considered one of the biggest obstacles in the atomic reflection process, is achieved. The performance of the atomic reflection process and some associated factors are pointed out and discussed.
Show AbstractInvestigations of photophysical processes in aqueous micellar solutions of fluorescein (F) were carried out by methods of stationary, time-resolved fluorescence spectroscopy and dynamic light scattering. It was found that the introduction of dye molecules into reverse micelles causes an increase in their hydrodynamic radii Rh proportional to the value of the degree of hydration w. The absorption and fluorescence spectra, the average lifetime of the excited state , and the degree of fluorescence anisotropy r of the F molecules are presented for various values of Rh. It was found that with an increase in Rh, the fraction of the anionic form of the dye in aqueous micellar solutions increases. In this case, an increase in the ratio of the dipole moments of the F molecules in the excited and ground states is observed, due to the structural reorganization of micelles. It was found experimentally that the rotational relaxation time of dye molecules decreases with increasing Rh, which indicates an increase in the microviscosity of the environment of F molecules due to the localization of dye molecules in the region of surface water in a micelle.
Show AbstractIn this work, by the method of dynamic light scattering, we obtained the pH dependences of the translational diffusion coefficient Dt and the hydrodynamic radius Rh in buffer solutions of collagen and collagenase in the presence of calcium, zinc, and chromium ions. A slight effect of metal ions on the molecules under study was revealed. The time dependences of Dt and Rh in collagen and collagenase solutions in the presence of an activator (Ca2+) and tanning agent (Cr3+) were measured, and the protein splitting rate constants were calculated. It was found that the addition of chromium ions slows down the collagenolysis process by 70% (or 3.3 times) (k1 = 0.006 (min-1)), compared with a pure solution of collagen and collagenase (k1 = 0.02 (min-1)). In turn, the presence of calcium ions accelerates the reaction by 250% (or 3.5 times) (k1 = 0.07 (min-1)). However, pre-chromed collagen is less susceptible to biodegradation due to activated collagenase (k1 = 0.009 (min-1)).
Show AbstractSchemes for measuring the presence or absence of interference, depending on the entanglement or non-entanglement of the states of the initial biphoton field, are proposed. It is shown that entanglement suppresses one-photon interference, but not two-photon interference, which can be observed in a scheme of the Franson interference type. Calculations are presented that confirm the efficiency of circuit solutions and conclusions made in the work.
Show AbstractThe method was proposed and a universal algorithm was built on its basis. This algorithm includes a full set of all structural solutions in the synthesis of antireflection multilayer structures and allows to synthesize a fully-antireflective two-component multilayer interference structure with randomly chosen real values of the refractive indices of the layers in the period for any real values of the refractive indices of matched media. Exact analytical relations were obtained, which make it possible to design antireflection structures with the minimal possible number of layers. The analysis and generalization of their structural and matching properties were carried out. The correctness of the obtained exact solutions and the efficiency of the method were validated by the numerical experiment.
Show AbstractThe outbreak of SARS-CoV-2 resulted in more than 4,000,000 infections and over 320,000 deaths. Coronavirus (S) spike glycoproteins promote entry into cells and are the main target of antibodies. We studied the effect of electron beams on the SARS CoV-2 glycoprotein and also on RNA using Monte Carlo simulation. We demonstrated that S-SARS CoV peak glycoproteins damaged by irradiation electrons corresponding to an energy loss of approximately 1.2 keV with damage of The efficiency can be as high as 68%.
Show AbstractHere we present an original CMOS compatible tecnique for fabrication a sensor system based on field-effect transistors with a nanowire channel and its application for the quantitative determination of thyroid-stimulating hormone (TSH) in model blood serum. The fabrication process is based on the reactive-ion etching of the upper layer of silicon on insulator through a mask formed by electron beam lithography. The detection is based on a change in the conductivity of the transistor during the selective interaction of the analyte with specific biomolecules on its surface. There were fabricated field-effect transistors with a nanowire channel of 70 - 90 nm wide and 3 - 5 mkm in long and a contact leads completely insulated from the analyte fluid. As the model antigen protein TSH of the pituitary gland, and as the recognition biomolecules - the specific to TSH fragments of antibodies were used, which were oriented immobilized on the nanowires surface. We carefully studied the conditions for biospecific interaction of antibodies with TSH. The detection limit of TSH was found to be 1x10-4 mkME/ml, which is significantly lower in comparison with currently used methods of standard enzyme-linked immunosorbent assay.
Show AbstractThe reaction cross-section and the energy, at which this value is obtained, are extremely important parameters in the calculation of astrophysical S-Factor. Astrophysical S-Factor values can be shown as one of the most notable values not only for nuclear reactions occurring at low energies but also for deeper understanding of astrophysical processes too. Considering the importance of this variable, it has been made possible to calculate it with theoretical methods when it cannot be measured experimentally. Theoretical calculations require the energy and the reaction cross-section values. While the reaction cross-section value, which can be explained as the probability of occurrence of a reaction, is obtained by theoretical calculations, the result can be affected by many parameters. In this study, it is aimed to investigate the effects of gamma-ray strength functions on the calculations of the astrophysical S-Factor values of 96Ru(a,g)100Pd, 106Cd(a,g)110Sn, 112Sn(a,g)116Te, 113In(a,g)117Sb and 144Sm(a,g)148Gd reactions by using the cross-section values obtained via utilizing different gamma-ray strength functions, which is one of the parameters known to have an effect on the cross-section calculations. All calculation results were obtained using a well-known computation code TALYS, and the data obtained were analysed both graphically and statistically against available experimental data from the Experimental Nuclear Reaction Data (EXFOR) Library.
Show AbstractUsing the quantum entanglement we propose a new algorithm for a hypothetical superluminal connection between the two macroscopic observers. It is shown that this algorithm is unworkable due to the properties of the monogamy of entanglement. It's a new look on the role of monogamy of entanglement in quantum mechanics. Ansible is a hypothetical device for superluminal connection from science fiction novels by Ursula Kroeber Le Guin.
Show AbstractThe place of adiabatic pressure fluctuations in turbulent mixing is analyzed in detail. They are used to explain smoothing of entropy spatial inhomogeneities and the sound speed fluctuations, as well as the energy transfer between kinetic and available potential forms. They characterize the uncertainty arising between the advection of pressure fluctuations in turbulent vortices and the work of the adiabatic fluctuations pressure force. Based on the assumption that the available potential energy is equally distributed between the adiabatic ($\si_p^a$) and turbulent ($\si_p^t$) components, it is shown that the incompressible and adiabatic fluctuations interaction characterizes the transition rate of kinetic energy into the available potential form and is comparable to the dissipation rate $\eps$.
Show AbstractThe statistical theory based on the parametric family of the Renyi entropy functionals is a generalization of Gibbs statistics. Depending on the value of the existing parameter, the corresponding Renyi distribution can take both an exponential form and a power-law form, which is typical for a wide range of statistical models. In this paper, we prove the equipartition theorem in the case of the Renyi statistics, which makes it possible to solve the problem of obtaining the average energy for a large number of classical statistical models. The proposed approach for calculating the average energy is compared with the procedure of direct calculation of this quantity for a system described by the simplest power-law Hamiltonian. New relations are presented that simplify the calculations in the considered theory. A special case of the Renyi distribution, which represents a generalization of the power-law distribution and allows us to approximate some empirical data more precisely, is studied.
Show AbstractA Monte Carlo-based 3D radiative transfer model has been developed to describe the reflection and scattering of solar radiation within heterogeneous vegetation cover. In the model the vegetation cover is considered as a group of trees with a similar spatial structure, modeled using fractal geometry. The architecture of an individual tree is described using data on its height, the number and length of branches of different orders, the angle of inclination of branches and the number of leaves. To obtain the distribution of the radiation field in vegetation, according to the model we calculated the contribution of each model "photon" taking into account its interaction and possible multiple scattering on vegetation elements and the soil surface based on the Lambert's law. Possible directions of photon propagation were determined according to the 9-th order quadrature formulas of the Gauss-Markov. The results of numerical experiments for the case of an individual tree have shown that the model is able to adequately describe the spatial heterogeneity of reflected and transmitted direct solar radiation.
Show AbstractThe paper presents a theoretical study of the correlation of errors in the thickness of layers of multilayer optical coatings under monochromatic control of their deposition processes. Estimates of the degree of correlation of errors in layer thicknesses are obtained for various algorithms for determining the stop time of deposition of coating layers. It is shown that the parameter introduced to assess the degree of correlation gives an adequate idea of the correlation of errors in monochromatic control.
Show AbstractPorous silicon was irradiated Ar+ ions with energies from 100 to 400 keV and fluence of 10^12 cm^(-2). The effect of ion irradiation at different energies of incident particles on the photoluminescence spectrum of porous silicon was studied. It was shown that the photoluminescence spectrum consists of two components. One of them associated with the presence of defects in the structure, and the other one associated with surface states on the complex surface of porous silicon. A method for estimating the thickness of the luminescent layer, based on the analysis of the photoluminescence peak associated with defects, is proposed.
Show AbstractThe type of magnetocrystalline anisotropy (MCA) of Sm-Fe-Co-Ti alloys and their hydrides with a ThMn12-type structure has been established by magnetometry at room temperature. Using atomic force microscopy (AFM) in combination with magnetic force microscopy (MFM), the state of their surface was studied. The initial SmFe11Ti and SmFe5Co6Ti samples were obtained by argon arc melting. The SmFe11Ti alloy was subjected to a hydrogenation procedure, as a result of which the SmFe11TiH0.4 and SmFe11TiH1 samples were synthesized. Using AFM and MFM, the features of topography, defects of the investigated surfaces, domain structure, morphology of magnetic inclusions of the initial samples and their hydrides were established. The main magnetic characteristics of the Sm-Fe-Co-Ti-H system obtained using magnetometry are compared with the results of MFM studies.
Show AbstractWe present results of an application of simple neural networks for recognizing events caused by charged particles hitting the photodetector of the first orbital telescope of ultra-high-energy cosmic rays TUS. Perceptrons with different number of hidden layers and convolutional neural networks were employed for the task. We provide details of the study and problems we faced, as well as their solutions. Results demonstrate effectiveness and good perspectives of using machine learning methods for an analysis and classification of data of similar experiments. The work will be continued and extended with the TUS detector data and with the Mini-EUSO experiment currently operating at the Russian Segment of the International Space Station.
Show AbstractThe results of a scientific and educational experiment on SiriusSat-1 and SiriusSat-2 spacecrafts carried out in Russia in the format “cubsat 1U +” are presented. Work on the creation of these satellites was started in July 2017 during the design shift of the Sirius educational center (Sochi) with the participation of schoolchildren. The technical support of the project in terms of payload, scientific tasks and data preparation is provided by the Research Institute of Nuclear Physics of Moscow State University, and in the part of the satellite platform and ground complex - the private Russian space company Sputniks. The launch of two SiriusSat-1,2 spacecraft was carried out on August 15, 2018 by astronauts from the ISS. The payload of the SiriusSat satellites is a detector based on several optically connected scintillators, which registers charged particles and γ-quanta in the energy release range of 0.3 - 3 MeV. The measurement mode provides for both second-second monitoring and a detailed mode with fixing the energy of each particle or quantum, as well as the corresponding moment in time with microsecond accuracy. Each satellite receives ~ 100 kb of scientific data on a daily basis available on the space weather server of the Research Institute of Nuclear Physics, Moscow State University. During the flight, a study is made of the variations in the fluxes of precipitating and quasi-trapped electrons of the external RPZ and at the border of the South Atlantic Anomaly, and the dynamics of the fluxes of particles and gamma rays depending on geomagnetic conditions is studied. Additional capabilities are provided by the analysis of the passage of areas of captured or precipitating particles by two closely flying satellites.
Show AbstractThe Moscow University program "Universat-SOCRAT" is aimed at using small satellites to monitor space threats, such as radiation in near-earth space, electromagnetic transients, and potentially dangerous bodies of natural and artificial origin. The implementation of the first stage of the program began on July 5, 2019 as a result of the successful launch of three cubesat-type nanosatellites from the Vostochny cosmodrome. These satellites are equipped with instruments for space radiation monitoring, as well as prototypes of devices for observing transient phenomena in the Earth's atmosphere. In particular, two satellites are equipped with scintillation phosphich detectors that detect charged particles and gamma quanta in the energy release range of 0.1–2.0 MeV. The geometric factor of these instrunebts is ~ 50 cm2•sr. One of the cubesats also contains an optical photometer, consisting of four silicon photomultipliers, which entrance windows are covered with different light filters. The satellites were launched into solar-synchronous orbits with an altitude of ~550 km. This makes favorable conditions for space radiation monitoring in various areas of near-Earth space, including zones of trapped radiation, areas of precipitation, etc. Such an orbit also allows observations of flare phenomena both in the equatorial atmosphere and at high latitudes. The first results of flight tests are discussed.
Show AbstractThe paper presents a formal proof that the mathematics on which the Special Theory of Relativity (STR) is based is currently misinterpreted. The evidence is based on an analysis of the importance of parameter e(v). Understanding the meaning of this parameter was achieved by analyzing the general form of transformation, for which the Lorentz transformation is only a special case. If e(v) ≠ 0 then the clocks in inertial systems are desynchronized. Measurements, e.g. one-way speed, using such clocks do not give real values. The article shows that there are infinitely many different transformations in which one-way speed of light is always equal to c. The Lorentz transformation is only one of those infinitely many transformations. In this article, the whole class of linear transformations of time and coordinate was derived. Transformations were derived on the assumption that conclusions from Michelson-Morley’s and Kennedy-Thorndikea’s experiments are met for the observer from each inertial frame of reference, i.e. that the mean velocity of light in the vacuum flowing along the way back and forth is constant. It was also assumed that there is at least one inertial frame of reference, in which the velocity of light in a vacuum in each direction has the same value c, and the space is isotropic for observers from this distinguished inertial frame of reference (universal frame of reference). Derived transformations allow for building many different kinematics according to Michelson-Morley’s and Kennedy-Thorndikea’s experiments. The class of transformations derived in the study is a generalization of transformations derived in the paper [10], which consists in enabling non-zero values of parameter e(v). The idea of such a generalization derives from the person, who gave me this extended transformations class for analysis and publication.
Show AbstractThe measurements of methane fluid flow from bottom sediments and daily monitoring of the main hydrophysical parameters near the seepage site in Laspi Bay were carried out. The values of fluid flows varied by an order of magnitude (1.4 - 74.3 mmol / m2 day) at points separated by a distance of not more than 10 m. It is assumed that denser carbonate deposits at the seepage site can localize gas flows, reducing the volume of fluid discharge. It was shown that the specific fluid discharge in Laspi Bay is comparable to the gas flow from single seep, the maximum fluid flow is only 3.5 times lower compared to the minimum flow recorded from the gas bubbles emission point. The change in hydrological parameters above the gas bubble discharge area is significantly affected by the weather conditions. Salinity сhanges during the measurements amounted to a limit value of 0.08 ‰, which indicates the absence of a high-yield freshwater submarine discharge, which is often associated withseepages. Episodes of abrupt decrease of oxygen content with amplitude 0.5 mg/l at night hours, not associated with changes in water temperature and weather conditions, can be caused by hydrogen sulfide inflow in bubble and fluid gases.
Show AbstractThe results of the analysis of detailed measurements of wind speed during the strongest squalls in Moscow on May 29, 2017 and April 21, 2018 are presented. For the first time in the Moscow region, the achievement of hurricane wind speed for the surface layer in squalls was noted. Using cross-wavelet analysis, the features of coherent changes in different components of wind speed in connection with extreme squalls are revealed. The features indicating the possibility of prognostic estimates for extreme squalls are noted.
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