Computer teaching of physics: mechanical oscillations and waves, kinematics and dynamics of solid body
Computer teaching of physics: mechanical oscillations and waves, kinematics and dynamics of solid body
V. Yu. Ivanov$^1$, I. B. Ivanova$^2$, M. A. Terentyev$^3$
An example of the interactive teaching test is presented. As tasks in investigation we consider the classical tasks of general physics from mechanics. The structure of the teaching test is suggested. Some examples of teaching tips are given.
Show AbstractThe kinetic Boltzmann equation and the problem of the foundation of statistical mechanics
The kinetic Boltzmann equation and the problem of the foundation of statistical mechanics
P. N. Nikolaev
In the paper it is investigated the role of the Boltzmann kinetic equation in the process of formation of the problem of the foundation of statistical mechanics. The main aspects of this problem, as well as its current state, are presented. There is considered the activity of N.N. Bogolyubov on solving questions related to the foundation of statistical mechanics.
Show AbstractConjugation of crystal structures in alloys with martensitic transformations: the possibility of constructing a habitus plane by methods of differential geometry
Conjugation of crystal structures in alloys with martensitic transformations: the possibility of constructing a habitus plane by methods of differential geometry
A. G. Khundjua$^1$, B. A. Volodin$^2$, E. A. Brovkina$^3$
The phase transformation austenite-martensite can be considered as a homogeneous deformation, as a result of which a sphere of unit radius turns into an ellipsoid of deformation. A method for determining the position of the habitus plane based on the analysis of the curvature of the spatial curve of the intersection of the sphere and the deformation ellipsoid is proposed. The algorithm includes finding the coordinates of the point of minimum curvature by numerical methods, determining the position of the straightening plane at the specified point, and the coordinates of the center of curvature. The vector "center of curvature – the point of minimum curvature" defines the normal to the habitus plane. Comparison of the calculated values of the invariant plane indices with the experimental ones showed satisfactory agreement for a number of alloys. It is possible that the deviation of the calculated data from the experimental data for some alloys is due to the need to take into account the deviation from the orientation relationship in the process of martensite transformation.
Show AbstractHeat capacity of liquid
Heat capacity of liquid
P. N. Nikolaev
The heat capacity of a liquid is investigated in the paper. For this, the cell-cluster expansion for the free energy is used, taking into account three-particle clusters, inclusive. A system was chosen as the reference one, the potential of interaction between particles of which is a generalization of the Weeks-Chandler-Andersen potential for the case of effective consideration of not only the influence of nearest neighbors, but also of particles on other coordination spheres. The calculations performed for liquid argon showed good agreement between the theoretical results and experimental data.
Show AbstractMicrowave absorbing properties of modified solid solutions based on bismuth ferrite and lead ferroniobate with different thermodynamic background
Microwave absorbing properties of modified solid solutions based on bismuth ferrite and lead ferroniobate with different thermodynamic background
P. A. Astafev$^1$, K. M. Zhidel$^1$, J. A. Reizenkind$^1$, L. A. Shilkina$^1$, L. A. Reznichenko$^1$
In this work, the microwave absorbing and resonance properties of solid solutions based on BiFeO3 and Pb(Fe0.5Nb0.5)O3 modified with GeO2 have been studied. The choice of these systems is justified by the high microwave absorbing properties of the components separately and the prospects of their applications in microwave technology. A method for studying cylindrical material samples on a microstrip line using a network analyzer is briefly described. The measurements were carried out in the frequency range of 300 kHz - 26.5 GHz. For measurements, 3 series of samples were prepared using different process conditions, 3-5 samples in each. This was necessary for collecting statistics. Studies have shown that with an increase in the porosity of the material, its radio-absorbing properties increase. In addition, the height of cylindrical samples does not qualitatively affect their properties, which will greatly facilitate the preparation of new samples for research. Materials with a high concentration of lead ferroniobate have high radio absorbing properties. The results obtained will help in the development of materials with controlled microwave absorbing properties for applications as microwave absorbing coatings, microwave substrates, resonator and filter materials.
Show AbstractExample of using the method of analysis of wave cloud photography over the Сrimea mountains
Example of using the method of analysis of wave cloud photography over the Сrimea mountains
V. N. Kozhevnikov
The paper presents a method for visual analysis of photographs of a wave multilayer cloud. It is shown that the cloud is located in the crest of orographic waves above the main ridges of the Crimean mountains. It is shown that the spatial characteristics of the cloud correspond to the results of calculations based on the previously created nonlinear model of the flow around mountains.
Show AbstractAssociated quarkonia production in a single boson $e^{+}e^{−}$~annihilation
Associated quarkonia production in a single boson $e^{+}e^{−}$~annihilation
E. A. Leshchenko$^1$, I. N. Belov$^2$
We present the preliminary results on the study of the cross sections for charmonium pair and bottomonium pair production in a single boson $e^+e^-$~annihilation. Processes have been studied in a wide range of energies, which are to be achieved at future $e^+e^-$~colliders, such as ILC and FCC. The contribution of color singlets states to production of vector and pseudoscalar states have been taken into account. Both QCD and EW production mechanisms have been considered including their interference and one-loop QCD correction. Cases of both intermediate bosons have been investigated: $\gamma$ and $Z$. All the calculations were performed in terms of perturbative technique and NRQCD-factorization.
Show AbstractModeling the interaction of solar radiation with vegetation elements using the Monte Carlo method
Modeling the interaction of solar radiation with vegetation elements using the Monte Carlo method
I. D. Sergeev, N. T. Levashova
The aim of this work is mathematical modeling of radiation transfer in vegetation cover elements, the geometry of which is close to real, using a software implementation of the Monte Carlo method. Information about the radiation reflected by a plant is needed to model the photosynthetic activity of trees, and consequently to model the carbon dioxide fluxes absorbed or released by plants, which is one of the most important tasks of ecology. By definition, the Monte Carlo method is a method for modeling random variables and processes to calculate the characteristics of their distributions. The process of radiation transfer in inhomogeneous media is modeled as a random Markov chain of collisions of photons with matter, and the purpose of the Monte Carlo method is to find the average statistical characteristics of this process. In this work, a small branch of birch is used as an object. In connection with the possibility of using modern multiprocessor systems for calculations it becomes necessary to distribute calculations, which can significantly reduce the time of realization.
Show AbstractFully heavy tetraquark spectroscopy in relativistic quark model
Fully heavy tetraquark spectroscopy in relativistic quark model
V. O. Galkin$^1$, E. M. Savchenko$^2$, R. N. Faustov$^1$
Masses of the ground and excited states of tetraquarks, composed of charm $c$ and bottom $b$ quarks and antiquarks, are calculated in the relativistic quark model based on the quasipotential approach and quantum chromodynamics. Relativistic effects are consistently taken into account. A tetraquark is considered as a bound state of a diquark and an antidiquark. The finite size of the diquark is taken into account, using the form factors of the diquark-gluon interaction. It is shown that most of the investigated states of tetraquarks lie above the decay thresholds into a pair of quarkonia, as a result they can be observed as broad resonances. The narrow state in the $J/\psi$ meson pair production spectrum recently discovered by the LHCb collaboration at Large Hadron Collider corresponds to the excited state of a fully charmed tetraquark.
Show AbstractThe method of equivalent substitutions, applied for the exact analytical solution of multilayer periodic structures with coupled wave thicknesses and specified amplitude-phase characteristics synthesis.
The method of equivalent substitutions, applied for the exact analytical solution of multilayer periodic structures with coupled wave thicknesses and specified amplitude-phase characteristics synthesis.
A. E. Zhitelev, A. V. Kozar
Based on the method of equivalent substitutions and the method of coupled wave thicknesses, a numerical analytical solution to the problem of calculations of the thickness values of the interference anti-reflective structure ("π structure") for an arbitrary number of layers is obtained. Exact algorithm is obtained that make it possible to synthesize antireflection structures providing a predefined reflection coefficient on the entire continuous set of values from 0 to 1 for any real values of the refractive indices of both matched media and materials of layers of such structures. The correctness of the obtained algorithm and the efficiency of the method are confirmed by a numerical experiment.
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