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SIBERIAN JOURNAL OF PHYSICS. Scientific Journal. 2022. V17, i
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Theoretical and Mathematical Physics
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Korol A. O., Nevedev K. V., Kapitan V. Yu. Neural Network Method for Calculation
of the Curie Point of the Two-Dimensional Ising Model // Siberian Journal of Physics. 2022. Vol. 17, no. 2, pp. 5–15. (in Russ.) DOI 10.25205/2541-
9447-2022-17-2-5-15
The authors describe a method for determining the critical point of a second order phase transitions using a convolutional
neural network based on the Ising model on a square lattice. Data for training and analysis were obtained using Monte
Carlo simulations. The neural network was trained on the data corresponding to the low-temperature phase, that is
a ferromagnetic one and high-temperature phase, that is a paramagnetic one, respectively. After training, the neural
network analyzed input data from the entire temperature range: from 0.1 to 5.0 (in dimensionless units J) and determined
the Curie point Tc.
Keywords
Ising model, Curie point, Monte Carlo method, Convolutional neural network
Funding
This work was supported by a grant from the President of the Russian Federation for State Support of Leading Scientific
Schools of the Russian Federation No. NSh-2559.2022.1.2. |
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High-Energy and Accelerator Physics, Physics of High-Temperature Plasma
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Sandalov E. S., Sinitsky S. L., Skovorodin D. I., Arzhannikov A. V., Logachev P. V., Bak P. A., Zhivankov K. I.,
Nikiforov D. A., Petrenko A. V., Ginzburg N. S., Nikolai Yu. Peskov N. Yu., Protas R. V. Investigation of the Increment
of Transverse Instability of a Kiloampere Electron Beam in a Linear Induction Accelerator for Its Use in a Terahertz
FEL. // Siberian Journal of Physics. 2022. Vol. 17, no. 2, pp. 16–29. (in Russ.) DOI 10.25205/2541-9447-2022-17-2-16-29
The Institute of Nuclear Physics SB RAS in cooperation with the Russian Federal Nuclear Center VNIITF performs
a series of researches aimed at acquiring a relative electron beam with energy up to 20 MeV, current up to 2 kA,
and duration up to 200 ns at normalized emittance ca. 1000 ï•mm•rad in a linear induction accelerator (LIA). In order
to generate electron beams with such parameters we require thorough investigation of all main sources of perturbation
of electron beam trajectory caused by different instabilities that occur during the transport and acceleration of a high
currency beam in the accelerating structure of LIA. For the experimental series on measuring the dynamics of transverse
oscillation of a beam, we applied a set of fast current transformers which are used for registration of beam current
and mode fields caused by this beam in the structure. These measurements were performed for the electron beam with
the energy of 8.5 MeV and current of 1 kA going through the structure at different modes of focusing magnetic fields size
in LIA. As a result, we registered oscillation of the electromagnetic field of normal modes in the accelerating modules
of LIA, as well as we determined the dependence of the oscillation amplitude of these modes’ EM field on the number
of accelerating module. This dependence was compared with the result of modeling of development dynamics
of transverse instability in LIA that was performed using the created program system. This allowed us to determine the
size of the increment of transverse instability of a relativistic electron beam under the given experimental conditions.
Based on the acquired results, we made the analysis of possibility to use the beam generated in ILA as a driver for the FEL
generator of coherent impulses of THz radiation within the frequency range of 0.3–1.2 THz with a sub-gigawatt level
of power.
Keywords
linear induction accelerator, high-current relativistic electron beam, transverse beam instability, accelerating module,
dipole oscillation, terahertz FEL |
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Physics of a Fluid, Neutral and Ionized Gases
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Piterimova M. V., Kosinov A. D., Semionov N. V., Yatskikh A. A., Kocharin V. L., Yermolaev Yu. G. Experimental study
of effect of a pair of weak shock waves on laminar-turbulent transition in the boundary layer of flat plate at Mach
number 2. // Siberian Journal of Physics. 2022. Vol. 17, no. 2, pp. 30–40. (in Russ.) DOI 10.25205/2541-9447-2022-17-2-30-40
An experimental study of the effect of longitudinal vortices generated by weak shock waves on the laminar-turbulent
transition in the boundary layer of a flat plate at a Mach number 2 is conducted. To amplify the effect of the longitudinal vortices generation, a model with leading edge blunting radius of 0,5 mm was used. The disturbance intensity was
measured with a constant temperature hotwire anemometer and a single-wire sensor. To change the Reynolds numbers
in the flow, the method of varying the pressure in the pretest section of a supersonic wind tunnel was used. According
to the experimental conditions, the level of mass flow perturbations in the test section T325 of ITAM SB RAS did not
exceed 0,1 % of the mean flow in the frequency range from 0,2 to 50 kHz. In this work, it is obtained for the first time
that stationary streamwise vortices that arise in the boundary layer of a flat plate because of the action of a pair of weak
shock waves on its leading edge lead to an early laminar-turbulent transition at different Reynolds numbers. In the case
of a homogeneous boundary layer, the transition is achieved at Rex ~ 3.1 * 106, and in measurements in the region
of vortices from shock waves at Rex ~ 1.5 * 106 è Rex ~ 2 * 106.
Keywords
supersonic flow, experimental studies, flat plate, laminarturbulent transition
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Lysenko V. I., Smorodsky B. V., Kosinov A. D. Effect of injection of gas with high specific heat capacity on supersonic
boundary-layer stability to controlled disturbances. // Siberian Journal of Physics. 2022. Vol. 17, no. 2, pp. 41–47.
(in Russ.) DOI 10.25205/2541-9447-2022-17-2-41-47
A study of the effect of distributed gas with high specific heat capacity blowing into the supersonic boundary layer on
its stability to artificial disturbances was conducted. It is shown that the injection of gas with high heat capacity Cp at
certain flow values can lead to the stabilization of the supersonic boundary layer.
Keywords
supersonic boundary layer, hydrodynamic stability, controlled disturbances, specific heat
Source of funding
The research was carried out within the state assignment of Ministry of Science and Higher Education of the Russian
Federation (project No.121030500161-0). |
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Rubtsov I. A. Two-stage carbon condensation model during detonation of high explosives. // Siberian Journal of Physics.
2022. Vol. 17, no. 2, pp. 48–55. (in Russ.) DOI 10.25205/2541-9447-2022-17-2-48-55
During detonating of high explosives with a negative oxygen balance, one of the products of the chemical reaction
is condensed carbon. However, the lack of experimental data does not allow us to give a quantitative assessment
of the carbon condensation process today. In this paper, a two-stage model of carbon condensation during the detonation
of high explosives is proposed. We used small-angle X-ray scattering method to study the dynamics of the formation
of carbon nanoparticles during the detonation of charges of a mixture of TNT and RDX.
Keywords
high explosives, detonation, carbon condensation, small-angle X-ray scattering, synchrotron radiation |
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Chemical, Biological and Medical Physics
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Osipova K. N., Shmakov A. G. Flame Structure of Ammonia/Hydrogen/Oxygen/Argon Mixtures at High Pressure. // Siberian Journal of Physics. 2022. Vol. 17, no. 2, pp. 56–68. (in Russ.) DOI 10.25205/2541-9447-2022-17-2-56-68
The search of alternative fuels is one of the most important issues. Hydrogen is the most attractive one since its
combustion products include only water. However, due to its specific properties wide implementation of hydrogen is
not possible. There is an idea to use chemical carriers of hydrogen, for example, ammonia. The addition of hydrogen,
which is the product of ammonia cracking, can improve the combustion characteristics of ammonia. The work presents
experimental data on the structure of NH3/H2/O2/Ar flames at 4 atm. Equivalence ratio values were 0.8, 1.0 and 1.2,
NH3/H2 ratio – 1/1. Flame structure was measured with molecular beam mass spectrometry with soft electron impact
ionization. In the experiments, flames were stabilized on the flat burner. Temperature profiles were measured with thin
S-type thermocouples. Numerical simulations were performed with PREMIX code from CHEMKIN package. The
comparison of the experimental and numerical data enabled to reveal the mechanism of NH3/H2 oxidation showing
the best predictive capability. Experimental and numerical data showed that the nitrogen-containing species which are
present in the post-flame zone are N2 and NO whereas concentration of N2O and NO2 is negligible. It was revealed that
in terms of NO reduction slightly rich conditions are more effective. In addition, the effect of equivalence ratio on the
peak concentration of NO, N2O and NO2 was analyzed. Rich conditions appeared to be more effective to reduce peak
concentrations of NO, N2O and NO2.
Keywords
ammonia, hydrogen, flame structure, mass-spectrometry
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Educational and Methodological Provision of Teaching of Physics |
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Bagayev S. N., Beterov I. I., Goncharov A. N., Chepurov S. V., Taichenachev A. V. Chair of Quantum Electronics of Faculty
of Physics NSU. // Siberian Journal of Physics, 2022, vol. 17, no. 2, pp. 70–74. DOI 10.25205/2541-9447-2022-17-
2-70-74
Chair of Quantum Electronics of Faculty of Physics of NSU educates highly-qualified researchers in modern laser
physics and laser technologies, high-precision laser metrology and quantum technologies in general. The chair is based
at the Institute of Laser Physics SB RAS.
Keywords
quantum electronics, laser physics, laser metrology, laser cooling, quantum technologies
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Tsybulya S. V. Section of Physical Methods of Solid State Research of the Department of Physics of Novosibirsk State
University. // Siberian Journal of Physics, 2022, vol. 17, no. 2, pp. 75–80. DOI 10.25205/2541-9447-2022-17-2-75-80
The article is devoted to the Department of Physical Methods for Solid Research of the Physics Department
of Novosibirsk State University, the basic institutes of which are the Boreskov Institute of Catalysis and the Nikolaev
Institute of Inorganic Chemistry of the Siberian Branch of the Russian Academy of Science. It tells about the history of the
foundation of the department, its lecturers and the directions of their scientific research, and also about the disciplines
studied. The reader can get acquainted with the list of department’s master’s programs and with the achievements of its
graduates and the prospects for further development.
Keywords
higher education, research methods, solid state, diffraction, spectroscopy, microscopy, synchrotron radiation
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Palchikov E. I., Kotelnikova M. S. Chair of Continuous Media Physics. // Siberian Journal of Physics, 2022, vol. 17, no. 2,
pp. 81–92. DOI 10.25205/2541-9447-2022-17-2-81-92
The paper talks about the history of the creation of the Chair of Continuous Media Physics of the Physics Department
of NSU, the scientific achievements of its employees and graduates, the teaching methods and hints, the fields of interest
in science.
Keywords
Chair of Continuous Media Physics, Institute of Hydrodynamics SB RAS
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Palchikov E. I., Seleznev V. A., Alekseev E. G. Lecture demonstrations of experiments in physics at the Novosibirsk State
University. // Siberian Journal of Physics, 2022, vol. 17, no. 2, pp. 93–104. DOI 10.25205/2541-9447-2022-17-2-93-104
The article tells about the 60-year history of the creation of a set of basic lecture demonstrations at the Physical
Department of the Novosibirsk State University and about the subdivision for demonstrations support – from the moment
the university was founded. The evolution of a set of demonstration installations, methodological descriptions
andtechniques for using equipment in the process of teaching physics in various situations is considered. It tells about
the people who made a great contribution at different stages of the transformation of DKF – a demonstration room in physics and MLDKS – an interfaculty laboratory of demonstrations and computer support. Bibliographic references
to catalogs with methodological descriptions of lecture demonstrations developed and created at NSU are given.
Keywords
demonstrations at the lectures, experiment, experimental problems, demonstration setups, physical experiments |
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Instructions to Contributors |
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