2304-9782, 2618-8686, 2405-7223 15 2 2022 1-150

RAR RUS 8-16 Herzen State Pedagogical University of Russia Sotova Yulia juliasotova1992@mail.ru Herzen State Pedagogical University of Russia Gorokhovatskiy Yuriy yurig@fromru.com Herzen State Pedagogical University of Russia Temnov Dmitry tde@herzen.spb.ru The role of the electret effect in the formation of the piezoelectric state in polyvinylidene fluoride-tetrafluoroethylene copolymer films In this work, the phenomenon of polarization of polyvinylidene fluoride-tetrafluoroethylene copolymer (P(VDF-TFE)) polymer films in the field of a corona discharge at elevated temperatures has been studied in order to elucidate the mechanism of formation of the piezoelectric state. The TSD spectroscopy was used to analyze the charge accumulation and relaxation processes occurring in the (P(VDF-TFE)) films during polarization. The results obtained made it possible to reveal an interrelationship of forming the electret and piezoelectric states in the (P(VDF-TFE)) as well as to explain the mentioned mechanism. On this basis a polarization procedure in the field of the corona discharge was developed and tested. This procedure permitted reducing the probability of electrical breakdown leading to mechanical damage of the films and allowed improving key characteristics of the objects under question. 10.18721/JPM.15201 538.9 electret state polyvinylidene fluoride tetrafluoroethylene piezoelectric effect TSD spectroscopy https://physmath.spbstu.ru/article/2022.56.1/ 01_8-16_15(2)2022.pdf

RAR RUS 17-25 0000-0002-2793-5717 Peter the Great St. Petersburg Polytechnic University Filimonov Alexey filimonov@rphf.spbstu.ru

St. Petersburg, Russian Federation

Peter the Great St. Petersburg Polytechnic University Bondarenko Vyacheslav vyacheslav.b.bondarenko@mail.ru Indian Institute of Technology Madras Kumar Ravi nvrk@iitm.ac.in

Chennai, India

A chaotic potential of charged dislocations in the III-nitride heterojunctions at high temperature The paper studies the high-temperature structure of a chaotic potential (CP) induced in heterojunctions of the group III nitrides by the electrostatic field of charged dislocations. The CP amplitude in the junction plane has been obtained taking into account the spatial dispersion of a dielectric response of two-dimensional electron gas. The dependence of the CP properties on the parameters of the system was found. In particular, the magnitude of the CP amplitude exceeds that of the thermal energy, if the two-dimensional non-degenerate gas given in III-nitride heterojunctions and the dislocation densities being up to and over 1010 cm–2. 10.18721/JPM.15202 537.9 chaotic potential natural size effect III-nitride heterojunction two-dimensional electron gas https://physmath.spbstu.ru/article/2022.56.2/ 02_17-25_15(2)2022.pdf

RAR RUS 26-33 0000-0003-0985-5964 Institute for Analytical Instrumentation of the RAS Berdnikov Alexander asberd@yandex.ru 0000-0002-6162-9481 Peter the Great St. Petersburg Polytechnic University Krasnova Nadezhda n.k.krasnova@mail.ru 0000-0002-0873-8849 Institute for Analytical Instrumentation of the Russian Academy of Sciences Masyukevich Sergey 0000-0003-3514-8577 Peter the Great St. Petersburg Polytechnic University Solovyev Konstantin k-solovyev@mail.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Visualization of the 3D stability zone of a quadrupole mass filter in the static longitudinal magnetic field A new visualization method has been put forward to show the three-dimensional stability zones of a quadrupole mass filter placed in the constant uniform magnetic field directed along the quadrupole axis. The three-dimensional zone was represented by a set of two-dimensional sections each of which being an analogue of a stability two-dimensional zone of an intermittent electric quadrupole. The procedure for redetermining the boundaries of stability regions for the two-dimensional sections was applied. The results obtained can be used both in design of new mass spectrometers and in analyses of periodic dynamic system stability. 10.18721/JPM.15203 537.533.7, 537.534.7, 681.2.084 quadrupole mass filter mass spectrometry stability zone Floquet theory https://physmath.spbstu.ru/article/2022.56.3/ 03_26-33_15(2)2022.pdf

RAR RUS 34-45 Lomonosov Moscow State University, National University of Science and Technology "MISiS" Tereshina Irina irina_tereshina@mail.ru Baikov Institute of Metallurgy and Materials Science, RAS, Peter the Great St. Petersburg Polytechnic University Politova Galina gpolitova@gmail.com

Moscow, Russian Federation, St. Petersburg, Russian Federation

Lomonosov Moscow State University Kaminskaya Tatiana ktp53@mail.ru

Moscow, Russian Federation

Lomonosov Moscow State University Popov Vladimir vvpopov@physics.msu.ru Institute of Molecule and Crystal Physic of the Ufa Federal Research Centre RAS Gunderov Dmitry dimagun@mail.ru 0000-0002-2793-5717 Peter the Great St. Petersburg Polytechnic University Filimonov Alexey filimonov@rphf.spbstu.ru

St. Petersburg, Russian Federation

National University of Science and Technology "MISiS" Pelevin Ivan pele.po4ta@yandex.ru Features of the nanostructure formation in the Nd-Pr-Fe-B-system alloys: a study by AFM and MFM 10.18721/JPM.15204 620.186: 539.378:537.622 atomic force microscopy magnetic force microscopy hard-magnetic material nanostructure https://physmath.spbstu.ru/article/2022.56.4/ 04_34-45_15(2)2022.pdf

RAR RUS 46-55 Peter the Great St. Petersburg Polytechnic University Antonova Daria nasada12@mail.ru Peter the Great St. Petersburg Polytechnic University Zotova Anastasia avotozana@gmail.com Peter the Great St. Petersburg Polytechnic University Usatykh Andrey andrew.usatih@yandex.ru Peter the Great St. Petersburg Polytechnic University Morozova Natalia natusmorozovna@gmail.com 0000-0003-2083-3643 Peter the Great St. Petersburg Polytechnic University Yakunina Maria yakuninam@nanobio.spbstu.ru Characterization of fluorescent proteins for STUdying the morphological rearrangements inside single bacterial cells during infection with phiKZ bacteriophage This work deals with evaluation of key properties of some fluorescent proteins (FPs) in order to use them for observation of redistributing the target proteins between the cytoplasm and pseudonucleus forming in bacterial cell infection by bacteriophage phiKZ. Four FPs, namely, mNeonGreen, mCherry, ECFP and EYFP, have been investigated using fluorescence microscopy. It was established that EYFP, unlike other objects, localized in the pseudonucleus during the infection. This phenomenon gave grounds to exclude EYFP from further experiments. As a result of analyzing the obtained values of FP key parameters, a set of FPs suitable for studying the process of bacterial cells infection by fluorescence microscopy was found. 10.18721/JPM.15205 577.359 fluorescent protein optical microscopy bacterial cell phiKZ bacteriophage https://physmath.spbstu.ru/article/2022.56.5/ 05_46-55_15(2)2022.pdf

RAR RUS 56-63 Peter the Great St. Petersburg Polytechnic University Tiba Ali alitiba1991@gmail.com P-6861-2015 10041592700 https://orcid.org/0000-0003-2511-0188 Karaseov Platon platon.karaseov@spbstu.ru 0000-0003-0309-5917 Peter the Great St. Petersburg Polytechnic University Berdnikov Yaroslav berdnikov@spbstu.ru Peter the Great St. Petersburg Polytechnic University Egorov Anatoliy egorov.a@spbstu.ru Peter the Great St. Petersburg Polytechnic University Mironova Svetlana Scaremonger@yandex.ru Features of the copper-64 isotope production using the MGC-20 cyclotron at St. Petersburg Polytechnical University The article deals with the technology of 64Cu isotope production by cyclotron proton irradiation of nickel foil of natural isotopic composition. In order to produce the 64Cu isotope, three nickel samples were irradiated with 13 MeV protons (beam current was 4 µA) for three hours using the MGC-20 cyclotron at SPbPU. After irradiation the samples were subjected to multistage radiochemical treatment aimed at refining the chemical form suitable for measuring the activities of 64Cu isotope and impurities. According to gamma spectrometric analysis, the 64Cu activity value was 30 MBq. The performed calculations of induced 64Cu isotope activity were based on the initial data and took into account the experimental conditions. A comparison of the experimental data with calculation results showed a good agreement between them. 10.18721/JPM.15206 539.1.03 copper-64 isotope cyclotron irradiation natural nickel foil comparison https://physmath.spbstu.ru/article/2022.56.6/ 06_56-63_15(2)2022.pdf

RAR RUS 64-78 Gazi University, Physics Department Ekinci Fatih fatih.ekinci2@gazi.edu.tr

Ankara, Turkey

Ankara University Bostanci Erkan ebostanci@ankara.edu.tr

Ankara, Turkey

Ankara University Güzel Mehmet mguzel@ankara.edu.tr

Ankara, Turkey

Gazi University Dağli Özlem ozlemdagli@gazi.edu.tr

Ankara, Turkey

Analysing the effect of a cranium thickness on a Bragg peak range in the proton therapy: a TRIM and GEANT4 based study Cancer treatment with proton therapy, starting in 1946, continues with the treatment of 200,000 patients worldwide as of 2020. The energy release of protons in tissue and tissue equivalent (water) material is shown by Bragg Curves. The main reason why proton beams are preferred in radiotherapy is that the proton beams continue on their way by giving maximum energy to the tissue to be treated and giving the least damage to the healthy tissue. In this study, with the help of Monte Carlo-based GEANT4 and TRIM simulation programs, Bragg peak positions in the 60 – 130 MeV energy range are given for water and brain by using the relativistic Bethe – Bloch equation. The difference between GEANT4 and TRIM was 7.4 % on average in the water phantom, while the difference was 7.6 % in the brain phantom. Bragg peak position was calculated for water and brain phantoms at 0.6, 0.8 and 1.0 cm thicknesses, which is suitable for the average thickness of the cortical bone in the skull. An average of 8.1 and 7.8 % deviations were detected between the two simulation systems in the cortical bony, water and brain phantoms with three different thicknesses. The values found were compared with the clinical studies available in the literature. 10.18721/JPM.15207 615.849.12 Monte Carlo GEANT4 TRIM radiation therapy proton therapy LET https://physmath.spbstu.ru/article/2022.56.7/ 07_64-78_15(2)2022.pdf

RAR RUS 79-92 Gauhati University Mahanta Chandra crmahanta@gauhati.ac.in

Guwahati, Assam, 781014, India

Gauhati University Das Manash manashpratimdas22222@gmail.com

Guwahati, Assam, 781014, India

Reconstructing quintessence scalar field model from new holographic dark energy in Bianchi type I universe In this paper, we investigate the cosmic evolution of a spatially homogeneous and anisotropic Bianchi type I universe filled with new holographic dark energy (NHDE) and cold dark matter (CDM) within the framework of General Relativity by considering both the components of the universe to be interacting with each other. To obtain the exact solutions of Einstein’s field equations, we consider two expansion laws: an exponential expansion and a power-law volumetric expansion. The evolutions of some parameters of cosmological importance are studied for both the models corresponding to the exponential expansion and the power-law volumetric expansion. We observe that in both the models the anisotropy parameter decreases as time evolves and tends to zero at late times. The model corresponding to exponential expansion behaves like CDM model and the model corresponding to power-law volumetric expansion behaves like quintessence holographic dark energy model at late time. We also compare the equation of state (EoS) and energy density of our interacting NHDE model with that of quintessence scalar field and establish a correspondence between them. The quintessence potential is reconstructed which depicts the observed accelerated expansion of the universe. 530.12:517.988 10.18721/JPM.15208 Bianchi type I universe new holographic dark energy quintessence EoS parameter https://physmath.spbstu.ru/article/2022.56.8/ 08_79-92_15(2)2022.pdf

RAR RUS 93-101 Nizhni Novgorod State Technical University named after R.Е. Alekseev Yurova Nadezhda yurova1980@yandex.ru On conjugacy classes of the F4 group over a field q with characteristic 2 This article continues a series of papers devoted to solving the problem by which a non-identity conjugacy class in a finite simple non-abelian group contains commuting elements. Previously, this statement was tested for sporadic, projective, alternating groups and some exceptional groups. In this article, the validity of the above-mentioned statement for the series exceptional groups 2F4(q) has been verified. After some basic definitions two theorems were proved. The former said about the content of commuting elements in the group, the latter did about the presence of conjugation of a semisimple element with its inverse. Then classes of unipotent and mixed elements were considered. The investigative techniques used were recommended for testing the general hypothesis when dealing with other groups. 10.18721/JPM.15209 512 Chevalley group conjugacy classes finite simple group commuting element https://physmath.spbstu.ru/article/2022.56.9/ 09_93-101_15(2)2022.pdf

RAR RUS 102-123 Peter the Great St. Petersburg Polytechnic University Savikovskii Artem savikovskij.av@edu.spbstu.ru Peter the Great St. Petersburg Polytechnic University Semenov Artem semenov.artem@googlemail.com Calculation of mixed-mode stress intensity factors for orthotropic materials in the plane stress state In the article, stress intensity factors for a straight crack of a mixed-fracture mode in the orthotropic material and in its particular case, namely, in the material with cubic symmetry, have been calculated. The displacement and stress extrapolation method based on the Lekhnitskii formalism was used. For considered classes of materials, the explicit expressions for influence matrix elements were obtained through the elastic constants of the material in the cases of its planar-stressed state and given a non-zero angle between the material’s anisotropy and the crack's axes. Influence matrix properties were analyzed systematically. The obtained results of verification of considered variants of the displacement and stress extrapolation method exhibited a good agreement between the numerical and analytical solutions (the difference did not exceed 0.8 %). 10.18721/JPM.15210 539.3, 539.42 Lekhnitskii formalism orthotropic material stress intensity factor mixed-mode fracture https://physmath.spbstu.ru/article/2022.56.10/ 10_102-123_15(2)2022.pdf

RAR RUS 124-139 Peter the Great St. Petersburg Polytechnic University, Institute of Problems of Mechanical Engineering of the Russian Academy Smirnov Alexey smirnov.alexey.1994@gmail.com Central Design Bureau of Transport Engineering Suvorov Sergei suvorovsv96@gmail.com

45v, Peterburgskoe HWY, Tver, 170003, Russia

Two-factor optimization in the brachistochrone problem The paper puts forward a new modification of the well-known brachistochrone problem. The joint account of minimizing the motion time and the trajectory length in their functional relationship has been introduced. A two-factor optimization criterion (TOC) was constructed in the form of a product of two particular criteria, which made it possible to find the best compromise between them. On the TOC basis a solution to the problem of a two-factor brachistochrone was obtained using a preliminary consideration of the auxiliary problem on a brachistochrone with a given length. A rational practical solution of the problem was proposed. It was characterized by a simpler geometry than the strictly optimal one: to adopt a circular arc with a central angle selected on the basis of the taken TOC. 10.18721/JPM.15211 531.332 brachistochrone optimization motion time trajectory length two-factor criterion rational solution https://physmath.spbstu.ru/article/2022.56.11/ 11_124-139_15(2)2022.pdf

RAR RUS 140-147 Peter the Great St. Petersburg Polytechnic University Lavrov Yury lyamm06@rambler.ru The response of a round plate and a cylindrical water-filled volume underneath to a point load moving periodically The two-dimensional problem of determining the steady-state field of enforced joint gravitational motions of incompressible fluid and a round elastic plate covering its surface has been considered. The motions are caused by a point load moving periodically along the outer surface of the plate, and refer to enforced harmonic oscillations in the system. A procedure for constructing an exact analytical representation of the vibrational field of the plate’s bending displacements was proposed. The unwanted mechanical resonance conditions were formulated. The results obtained make it possible to find bending moments and shear forces, if need be, in assessment of the strength of a plate. Moreover, they may be useful, for instance, in organizing safe regular movement of vehicles on a layer of ice covering a body of water. 10.18721/JPM.15212 517.947:534.414 cylindrical reservoir gravitational fluid motion elastic plate moving load harmonic oscillations https://physmath.spbstu.ru/article/2022.56.12/ 12_140-147_15(2)2022.pdf