Issue 4, 2025
Water Formation in Asteroids
Water Formation in Asteroids
A. Yu. Dubinsky$^1$, S. I. Popel$^1$, J. S. Reznichenko$^{1,2}$
The issue of the formation of water molecules in asteroid regolith is considered. The possibility of oxygen atoms release as parts of silver hydroxide molecules from the crystal lattice of silicon dioxide in regolith has been demonstrated. Silver hydroxide, in turn, can react with hydrogen relatively easily, resulting in the formation of water and silver. This demonstrates the possibility of the formation of water molecules included in the near-surface soil of an asteroid. The proposed mechanism for the formation of water molecules does not require such an unlikely event as two solar wind protons hitting the same point. In the situation under consideration, it is only required that the end of the proton track fall in the region where the elements of the quartz lattice, for example, metal sulfide, are in contact with each other. The presence of water molecules in the soil of an asteroid can affect the photoelectric properties of its regolith and the parameters of the plasma-dust system above the asteroid. A way to identify the nature of the formation of water on an asteroid can be a combination of the method of finding water on asteroids, based on the detection of dust near the surfaces of these space objects, as well as a method using the detection of neutron fluxes passing through areas of the surface of the space body.
Show AbstractBlack Hole shadows in loop quantum gravity with rotation taken into account
Black Hole shadows in loop quantum gravity with rotation taken into account
S. O. Alexeyev$^{1,2}$, E. A. Antonov, O. I. Zenin$^2$
In the frames of the theory of loop quantum gravity (LQG) the new black hole metric is studied. The BH central singularity is replaced by a traversable tunnel. Additionally, the metric includes a tidal charge. With the help of the Newman-Janis algorithm a rotating version of this BH solution is derived. The corresponding shadow profile is calculated and the shadow radii are compared with constraints from Event Horizon Telescope (EHT) observations. The results reveal a discrepancy with predictions from general relativity (GR) which may be explained by the impact of quantum corrections.
Show AbstractNarrow-linewidth IR laser modulation by quantum cascade laser structure
Narrow-linewidth IR laser modulation by quantum cascade laser structure
S. A. Chakhlov$^{1,2}$, L. A. Miklashevich$^1$, A. A. Lastovkin$^1$, N. G. Zakharov$^1$
The effect of modulation of narrow-linewidth laser radiation in the 1590 nm range, passed through the waveguide structure of a quantum cascade laser, is obtained, observed when applying an electric voltage to the structure. This effect reveals the thermodynamics of the active region of a quantum cascade laser operating in a pulsed mode, which is relevant in the problem of optical communication implemented on the principle of high-frequency amplitude signal modulation.
Show AbstractNeural networks assisted reconstruction wavefront of laser radiation based on intensity profile near focus of converging lens
Neural networks assisted reconstruction wavefront of laser radiation based on intensity profile near focus of converging lens
N. V. Iakushkin$^{1,2}$, A. V. Mitrofanov$^{1,2,3}$, A. V. Vasil'ev$^1$, A. V. Larichev$^{1,3}$, N. G. Iroshnikov$^1$, D. A. Sidorov-Biryukov$^{1,2,3}$
The architecture ConvFormer S18 network allows reconstruct the shape of the laser radiation wavefront from the intensity distribution near the lens focus. The use of normilizing method for sparse data can reduce RMS error of wavefront reconstruction by the factor of 2. Ability of neural network to reconstruct laser radiation wavefront based on its intensity profile near focus of converging lens is experimentally demonstrated for set of abberations applied simultaneosly. RMS-error of wavefront reconstruction in the experiment from the intensity distribution taken behind the focus, in front of the focus, and from the data from both positions were estimated as 𝜆/18 , 𝜆/13 and 𝜆/31. The correctness of the technique is proven by the coincidence of the calculated intensity distribution based on data obtained by the neural network with the measured experimental values.
Show AbstractSpatiotemporal dynamics of terahertz pulses generated by photoconductive semiconductor antennas based on LT-GaN
Spatiotemporal dynamics of terahertz pulses generated by photoconductive semiconductor antennas based on LT-GaN
E. R. Burmistrov$^{1,2}$, L. P. Avakyants$^1$, N. A. Parfent’eva$^2$, S. N. Gavrilin$^2$
Analytical expressions describing the spatiotemporal dynamics of terahertz pulses in a medium with refractive index dispersion, representing a single-period oscillation of an electric field, are obtained. An attempt is demonstrated to approximate the real radiation from a photoconductive semiconductor antenna based on GaN using the expressions obtained. Comparison with experimental spectra has shown that the proposed formulas successfully describe the single-period emission of terahertz pulses generated by photoconductive antennas under the influence of femtosecond laser pulses. It is shown that in the far diffraction zone, terahertz pulses undergo diffraction broadening, acquiring the character of a one-and-a-halfperiod oscillation.
Show AbstractTheoretical calculations of $^{161}$Tb production on dysprosium isotopes
Theoretical calculations of $^{161}$Tb production on dysprosium isotopes
N. Yu. Fursova$^{1,2}$, R. A. Aliev$^3$, S. S. Belyshev$^{1,2}$, A. A. Kuznetsov$^{1,2}$
In the present work, based on the combined model of photonucleon reactions, the activities of the promising medical isotope $^{161}$Tb produced by the $^{162}$Dy($\gamma$,1p) and $^{163}$Dy($\gamma$,1n1p) reactions were calculated for electron beam energies ranging from the reaction threshold to 55 MeV. Photonuclear isotope production also requires information on the formation of side nuclides, so the reactions $^{162}$Dy($\gamma$,1n1p), $^{163}$Dy($\gamma$,1p) and $^{163}$Dy($\gamma$,2n1p) were studied. The results of calculations indicate the possibility of using the monoisotopic target of $^{162}$Dy at electron beam energies of 21-22 MeV and the monoisotopic target of $^{163}$Dy at energies of 29-30 MeV for photonuclear production of $^{161}$Tb.
Show AbstractForm Factor and Mean-Square Radius for the Vector Current of Component System of the Two Particles with Arbitrary Masses and Spin 1/2
Form Factor and Mean-Square Radius for the Vector Current of Component System of the Two Particles with Arbitrary Masses and Spin 1/2
Yu. D. Chernichenko
The new expressions for the form factor components and mean-square radius for the vector current of the composite system of two relativistic particles with arbitrary masses and spin 1/2 are obtained. The pseudoscalar, vector and pseudovector composite systems were considered. For them is received identity, which installs the dependency between masses and quarks spin, forming composite systems. Values of the mean-square radius of the ground-state s-wave level of pseudoscalar π±-, K±- and K0-mesons with the Coulomb interaction are calculated. The analysis is performed and the dependency of behavior mean-square radius concerning the differences of quarks masses, forming mesons, is installed. Consideration is conducted within the framework of relativistic quasipotential approach on the basis of covariant Hamiltonian formulation of quantum field theory by transition to the three-dimensional relativistic configurational representation in the case of two relativistic spinor particles with arbitrary masses.
Show AbstractHard bremsstrahlung for prompt photons production processes
Hard bremsstrahlung for prompt photons production processes
A. A. Kampf
This work describes the analytical calculation of the amplitude for hard photon and gluon bremsstrahlung using the spinor formalism for processes such as $\bar{q} q \to g \gamma$ and $q g \to q \gamma$. The amplitude is presented in a gauge-invariant form, accounting for particle polarizations and masses. Numerical calculations have been performed for the annihilation process of a $\bar{c}c$ quark pair at energies of 24, 91, and 500 GeV in the center-of-mass frame, taking into account various combinations of the helicities of the quarks and the photon in the final state. The study is part of the ongoing development of a theoretical framework within the {\tt SANC} system, aimed at analyzing polarized observables in proton-proton collisions at the \texttt{NICA} collider.
Show AbstractPrediction of viscosity of binary mixtures of hydrocarbons and carbon dioxide using the Lorenz–Bray–Clark model
Prediction of viscosity of binary mixtures of hydrocarbons and carbon dioxide using the Lorenz–Bray–Clark model
E. E. Volodina, A. V. Isaeva
The article shows the feasibility of using the direct energy minimisation method in conjunction with the Peng-Robinson equation of state and the Lorenz-Bray-Clark model to calculate the density and viscosity of binary hydrocarbon mixtures, as well as mixtures of hydrocarbons with carbon dioxide. The accuracy of the numerical simulation results was assessed by comparing the calculated values of the density and dynamic viscosity of the phases (liquid and gas) with experimental data published in the literature. It is shown that the approach considered in the article makes it possible to predict with good accuracy (up to 10 %) the values of density and viscosity of phases for binary hydrocarbon mixtures, which include components containing up to eight carbon molecules.
Show AbstractCausal relations between climate and carbon cycle taking into account natural climate variability and economic cyclicity of greenhouse gas anthropogenic emissions into the atmosphere
Causal relations between climate and carbon cycle taking into account natural climate variability and economic cyclicity of greenhouse gas anthropogenic emissions into the atmosphere
K. E. Muryshev$^{1,2}$, A. V. Eliseev$^{1,2,3}$, I. I. Mokhov$^{1,2}$, S. N. Denisov$^2$, A. V. Timazhev$^2$, G. P. Klimovich$^1$
The results of the analysis of time lags between variations in global surface temperature T and atmospheric CO2 content q, obtained in numerical simulations with the IAP RAS-MSU Earth System model (IAP RAS-MSU ESM) for the period 2020-3000 are presented. In these simulations variations in the energy flux into the climate system associated with natural climatic variability, in particular with a period of about 60 years, and changes in anthropogenic CO2 emissions into the atmosphere were taken into account in accordance with the SSP1-2.6 scenario, continued until 3000 with addition of variations with a period of 50 years, modeling Kondratiev's economic cycles. It is found that changes in T can both lead or lag changes in q, depending on the time interval at which the time lag between T and q is investigated. The results depend on the ratio of the amplitudes of variations in anthropogenic CO2 emissions and variations in the energy flux into the climate system associated with natural variability. The effects that manifest themselves in case of their comparable contribution to the change in T are explained using analytical solutions of a system of equations describing the dynamics of the Earth system in a simplified form. The results obtained indicate that, in general, it is impossible to judge the nature of the cause-and-effect relationship between variables by the time lag between changes in variables without involving physical representations of the nature of their interaction.
Show AbstractEarth's dipole magnetic field: conditions of existence
Earth's dipole magnetic field: conditions of existence
M. Yu. Reshetnyak
Since the formation of the Earth's core and up to the present time, there has been a significant change in the thermal regime on the Earth's surface and in the mantle. At the same time, according to paleomagnetic observations, the dipole magnetic field has not undergone significant changes. Using a parametric model of core and mantle cooling, the paper discusses how this fact agrees with the results of three-dimensional geodynamo modeling. It is shown that several-fold changes in the heat flow at the core-mantle boundary do not cause a change from a dipole magnetic field to a multipole one.
Show AbstractA new site of methane fluxes near Cape Ayu-Dag: first data on gas flows and genesis
A new site of methane fluxes near Cape Ayu-Dag: first data on gas flows and genesis
A. A. Budnikov$^1$, E. A. Krasnova$^2$, T. V. Malakhova$^3$
The article has been received and signed into print The studies carried out at the new methane sips site, discovered during sonar near Cape Ayu-Dag, complement the data on the distribution of shallow-water gas emissions off the Crimean coast of the Black Sea. Using the passive acoustic method, the nature of gas emissions was determined and the bubble gas flow was estimated, which ranged from 1.0 to 1.6 liters per hour and turned out to be similar in magnitude to other shallow-water gas occurrences on the southern coast of Crimea. Preliminary data from isotopic and gas chemical analysis demonstrated the biogenic nature of the released gas. Further monitoring will make it possible to assess the seasonal and interannual dynamics of the activity of the detected barnacles at Cape Ayu-Dag, as well as the isotopic and chemical characteristics of the gases.
Show AbstractAnomalous Behavior of Gap Intensity in Paired Alkali Metal Nanoparticles with Mesoscopic Boundary Conditions
Anomalous Behavior of Gap Intensity in Paired Alkali Metal Nanoparticles with Mesoscopic Boundary Conditions
Yu. A. Eremin, V. V. Lopushenko
In this paper, we study the influence of a surface quantum effect on the field intensity in a nanometer gap of a pair of gold and sodium nanoparticles. The quantum effect is taken into account based on mesoscopic boundary conditions, including the Feibelman parameters. The simulation was carried out using the discrete source method, which allows calculating near fields with guaranteed accuracy. As a result of the comparative analysis, significant differences in the field intensity in the nanometer gap between gold and sodium particles were discovered. It was found that when taking into account the quantum effect, the field intensity in the gap between sodium particles is higher than in the classical case. This significantly distinguishes them from the gold pair, where taking into account the quantum effect leads to a decrease in intensity.
Show AbstractMethod for Obtaining a Bistatic RCS Diagram of a Body Using Near-Field Data on a Plane or Cylinder with Discrete Sources
Method for Obtaining a Bistatic RCS Diagram of a Body Using Near-Field Data on a Plane or Cylinder with Discrete Sources
N. P. Balabukha$^1$, D. A. Konyaev$^{1,2}$, N. E. Shapkina$^{1,2}$
Today, most measuring systems allow obtaining monostatic radar cross section (RCS), but the ability to obtain bistatic RCS is very important from a practical point of view. Therefore, it is necessary to modernize existing compact ranges in order to measure bistatic RCS. In practice, a near-field scanner is often used for this purpose, with subsequent calculation of the far-field and the corresponding bistatic RCS. In this paper, a method based on the ideas of the discrete source method is proposed for calculating the RCS based on the near-field values when scanning on a plane or part of cylindrical surface. The proposed method is tested by a numerical experiment. A comparison of the results of the presented method with the results obtained by the traditional method of near-field to far-field transform is carried out.
Show AbstractSteady-state solution of a two-component reaction-diffusion system with a singular source of the fast component at the boundary
Steady-state solution of a two-component reaction-diffusion system with a singular source of the fast component at the boundary
K. A. Kotsubinsky$^1$, N. T. Levashova$^2$
The paper formulates conditions and proves a theorem on the existence of a Lyapunov-stable stationary solution to a system of reaction-diffusion equations with slow and fast components in a two-dimensional case. A feature of the statement is the singular Neumann boundary condition for the fast component. The asymptotic method of differential inequalities was used to obtain the result. The results obtained are of practical importance for various applications, such as modeling chemical reactions occurring inside a rock in oil production problems, as well as developing effective numerical methods for solving boundary value problems for elliptic equations.
Show AbstractSynthesis of parameters of a photonic crystal that supports a Bloch wave for a maximum time
Synthesis of parameters of a photonic crystal that supports a Bloch wave for a maximum time
A. N. Bogolubov, A. D. Nikitchenko
The article is devoted to the optimization of the bound state lifetime of the Otto coupler. As a result of the optimization of the initial configuration, the bound state lifetime was increased from 943 femtoseconds to 18367 femtoseconds. The influence of such parameters as layers thickness, refractive indices, the number of bilayers in the photonic crystal, and the angle of incidence of radiation on the bound state lifetime was studied. The obtained results demonstrate a significant potential of layered structures based on Bloch surface waves for application in integrated nanophotonics.
Show AbstractHigher $\varepsilon$-poles and logarithms in the MS-like schemes from the algebraic structure of the renormalization group
Higher $\varepsilon$-poles and logarithms in the MS-like schemes from the algebraic structure of the renormalization group
N. P. Meshcheriakov$^1$, K. V. Stepanyantz$^1$, V. V. Shatalova$^2$
We investigate the structure of renormalization constants within the MS-like renormalization prescriptions for a version of dimensional regularization in which the dimensionful regularization parameter $\Lambda$ differs from the renormalization point $\mu$. Namely, we rewrite the all-loop equations relating coefficients at higher $\varepsilon$-poles and higher powers of $\ln\Lambda/\mu$ to the coefficients of the renormalization group functions in a simple unified form. It is argued that this form follows from the algebraic structure of the renormalization group.
Show AbstractThe phenomenological model electric charge distribution in a nonuniformly stressed conductor
The phenomenological model electric charge distribution in a nonuniformly stressed conductor
O. N. Gavrish$^1$, I. P. Denisova$^{1,4}$, N. V. Kalenova$^2$, E. T. Eniev$^3$
The analysis of the phenomenological model of the baroelectric effect, developed in the works of Professor V.I.Grigoriev, is carried out. This model contains two groups of equations: equations describing the motion of the elements of the volume of a solid and a phenomenological equation determining the density of the electric charge generated in conductors under the action of an inhomogeneous voltage. The latter of them can be represented in two forms, when the density of the electric charge arising in electroneutral conductors under the action of an inhomogeneous voltage requires a non-zero surface charge density, and when the surface charge density is zero for any pressure distribution along the conductor. In the works of Professor V.I. Grigoriev, a phenomenological model of the baroelectric effect was considered, which requires the presence of an electric charge density not equal to zero on the surface of the body . The purpose of this work is to study the baroelectric effect using a phenomenological equation that does not require electric charges on the surface of a body.
Show AbstractThermal equation of state for a system with a two-particle interaction potential in R{\'e}nyi statistics
Thermal equation of state for a system with a two-particle interaction potential in R{\'e}nyi statistics
D. V. Nakashidze$^1$, A. M. Savchenko$^1$, K. M. Semenov$^1$
This paper is devoted to the development of the generalised formalism of statistical physics. The thermal equation of state for a gas with a two-particle interaction potential in the Renyi statistics formalism is obtained. An auxiliary inverse temperature distribution providing the established dependence of the terms in the equation of state on the generalising parameter $q$ is introduced and considered. On the basis of the obtained results, an expression for the average energy of the system under study in R{\'e}nyi statistics is written down, assumptions about the possible nature of the parameter $q$ are put forward, and promising directions for further research are outlined.
Show AbstractMethod for Three-Dimensional Collimator Mirror Model Designing with rolled edges based on two-dimensional synthesis problems solutions
Method for Three-Dimensional Collimator Mirror Model Designing with rolled edges based on two-dimensional synthesis problems solutions
M. I. Propoy$^1$, F. B. Khlebnikov$^1$, D. A. Konyaev$^{1,2}$, N. E. Shapkina$^{1,2}$, A. N. Bogolubov$^1$
This paper considers the problem of designing a three-dimensional mirror collimator of complex shape with blended rolled edges for an anechoic chamber with known size. The collimator model is created based on its two-dimensional sections with pre-optimized geometric parameters. The simulation of the formation of the electromagnetic wave field reflected from such a three-dimensional collimator at different frequencies and polarizations of the incident wave is carried out.
Show AbstractSome Features of the Functional Activity of Multiwall Carbon Nanotubes in Polymer Nanocomposites
Some Features of the Functional Activity of Multiwall Carbon Nanotubes in Polymer Nanocomposites
N. G. Chechenin$^{1,2}$, V. A. Kobzev$^{1,2}$, S. S. Avtorin$^{1,2}$, E. A. Vorobyeva$^1$, A. V. Makunin$^1$
The paper examines the dependence of the functional activity of multiwall carbon nanotubes (MWCNTs) in polymer nanocomposites (PNCs) on the number of layers and the concentration of MWCNTs in the polymer matrix. The analysis shows that the functional activity decreases inversely proportional to the number of MWCNT layers. An increase in the concentration of MWCNTs in the polymer matrix is accompanied, on the one hand, by an increase in the functional activity of MWCNTs due to an increase in the total active surface, and on the other hand, by a decrease due to a decrease in the specific active volume of the polymer matrix. This leads to a peak-shaped dependence of the functional activity of MWCNTs on their concentration in the polymer, which is confirmed by experimental data on the impact resistance of polymer MWCNT composites.
Show AbstractMagneto-optical effects of ferromagnetic metals in the terahertz region of the spectrum
Magneto-optical effects of ferromagnetic metals in the terahertz region of the spectrum
M. A. Simdyanova$^{1,2}$, A. B. Granovsky$^{1,3,4}$
Expressions for the magnetorefractive effect and the equatorial Kerr effect of collectivized ferromagnetic metal electrons in the terahertz region of the spectrum are obtained using the Maxwell equations and the kinetic Boltzmann equation. It is shown that the magnetorefractive effect (a change in the reflection coefficient when reflecting unpolarized terahertz radiation from the surface of a magnetoresistive metal) is proportional to the magnetoresistance, and the Kerr effect can reach values of the same order of magnitude as for the visible range of the spectrum. The possibility of using these effects is discussed.
Show AbstractSurface topography modification of additive manufactured Ti6Al4V and AlSi10Mg alloys under argon cluster ion irradiation
Surface topography modification of additive manufactured Ti6Al4V and AlSi10Mg alloys under argon cluster ion irradiation
D. S. Kireev, D. R. Bessmertniy, V. S. Chernysh, A. E. Ieshkin
This work investigates the possibility of controlled surface topography modification of additive manufactured Ti6Al4V and AlSi10Mg materials using 10 keV argon cluster ion irradiation. The influence of the cluster ion incidence angle on the resulting surface morphology is demonstrated. Normal incidence irradiation of Ti6Al4V and AlSi10Mg surfaces with cluster ions results in a decrease in surface roughness from 6.2 nm to 0.89 nm and from 16.8 nm to 4.27 nm, respectively (according to atomic force microscopy data for a 3×3 m scan area). The spatial wavelength range in which significant surface smoothing occurs is identified. Oblique cluster ion irradiation leads to the uniform formation of an ordered ripple structure, regardless of the crystallite orientation or material phase.
Show AbstractModification of the surface topography and composition of a nickel-based superalloy under gas cluster ion beam irradiation.
Modification of the surface topography and composition of a nickel-based superalloy under gas cluster ion beam irradiation.
A. V. Nazarov$^{1,2}$, D. S. Kireev$^2$, E. S. Kosenyuk$^{1,2}$, A. A. Tatarintsev$^2$, A. V. Lubenchenko$^3$, O. N. Pavlov$^3$, P. N. Degtyarenko$^{4,5}$, A. S. Shemukhin$^{1,2}$
The present study is devoted to the modification of the surface structure and composition of the nickel-based superalloy Hastelloy C-276 under 10 keV Ar gas cluster ion beam (GCIB) irradiation. The possibility of either smoothing or nanostructuring of the surface relief following preliminary electrochemical polishing is demonstrated. The changes in the alloy's surface composition under gas cluster irradiation are also examined.
Show AbstractCalculation of mass distributions of Cu fragments sputtered by Ar cluster ions based on molecular dynamics simulation
Calculation of mass distributions of Cu fragments sputtered by Ar cluster ions based on molecular dynamics simulation
A. V. Nazarov$^{1,2}$, D. S. Kireev$^2$, A. N. Rattsev$^2$, V. S. Chernysh$^2$
Molecular dynamics simulation of the interaction processes of Arn clusters with the Cu surface at different E/n ratios was performed. The distributions of sputtered fragments by mass were calculated. It was shown that these distributions are described by a power law as a function of the fragment size. The dependences of the exponent on the energy and the size of the primary cluster were studied; it was shown that it correlates with the total sputtering yield similarly to the case of sputtering by atomic ions.
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