2304-9782, 2618-8686, 2405-7223 11 2 2018 1-168

RAR RUS 9-15 Meredelina Tatiana A. biofirm@mail.ru Amur State University Stukova Elena lenast@bk.ru Blagoveschensk State Pedagogical University Baryshnikov Sergey svbar2003@list.ru Blagoveshchensk State Pedagogical University Milinskiy Alexey a.milinskiy@mail.ru The ferroelectric phase transition in the ammonium iodate embeded into the alumina porous matrix The temperature dependences of the linear permittivity ε' and the harmonic coefficient γ of composite materials obtained by embedding the ferroelectric NH4IO3 into the porous alumina (Al2O3)  matrix with a pore diameter of 60 nm were studied. It has been found  out that the phase transition is diffused and the Curie temperature shifts to a low-temperature region T ~ 25 K. The results obtained are interpreted within the framework of the phenomenological Landau theory and the Ising model. On the basis of these theoretical descriptions of the demonstration that the phase transition temperature in a nanocomposite is a consequence of dimensional effects. At the same time, the electrical interaction between particles in adjacent pores does not play an important role, due to the low spontaneous polarization of ammonium iodate and significant distances between neighboring pores. 10.18721/JPM.11201 537.226.33. ferroelectric dielectric permittivity nanocomposite phase transition https://physmath.spbstu.ru/article/2018.40.1/ 01_9-15_11(2)2018.pdf

RAR RUS 16-25 Peter the Great St. Petersburg Polytechnic University Dyubo Dmitry doobinator@rambler.ru Peter the Great St. Petersburg Polytechnic University Tsybin Oleg otsybin@rphf.spbstu.ru The relation of volume and surface effects with a charge barrier height in a dynamic p–i–n-photodyode The characteristics of the microelectronic dynamic operational p–i–nphotodetector have been analyzed. These features are determined by the interaction of volume effects with particles adsorbed on the SiO2 film surface. The temperature characteristics in the visible light irradiation regime, the anomalous characteristics of the temperature hysteresis, the processes in the adsorbed layer and the charge carriers’ transport through the potential barrier in the Si substrate bulk were considered. The photocurrent sensitivity of the device was found to depend nonlinearly on temperature. We proposed a theoretical model that related the processes of thermaland photo-generation of the charge carriers with the potential barrier parameters. The effects resulted from the formation of the surface charges were revealed. The optimal conditions and regimes for measuring the photocurrent were determined. 10.18721/JPM.11202 621.383.522 dynamic p–i–n-diode temperature hysteresis volume effect charge barrier https://physmath.spbstu.ru/article/2018.40.2/ 02_16-25_11(2)2018.pdf

RAR RUS 26-40 Romanov Nikolay nikromanov.90@gmail.com Peter the Great St. Petersburg Polytechnic University Zakharova Irina zakharova@rhpf.spbstu.ru Elistratova Marina marina.elistratova@mail.ioffe.ru Lähderanta Erkki Erkki.Lahderanta@lut.fi The structure of ZnTPP, ZnTPP-C60 thin films and X-ray effect on their photoluminescence The paper presents the results of studies in properties of ZnTPP and nanocomposite ZnTPP-C60 films prepared under quasi-equilibrium conditions. The films’ composition, structure and surface morphology have been investigated. Inequality in the optical absorption and photoluminescence (PL) spectra of ZnTPP solution and ZnTPP film was testimony to the formation of a regulated phase with the 745 nm-phosphorescence at room temperature. The X-ray effect on the PL spectra of ZnTPP and ZnTPP-C60 films was considered. The former was rather stable to the used X-ray doses. The dose dependences of electronic and electron-vibrational contributions to the PL emission intensity were different for the latter. A decrease in the emission intensity due to the electronic transition in the composite was caused by a probability increase in an excitation transfer from the carrier to the fullerene C60 and, correspondingly, by PL suppression. 10.18721/JPM.11203 621.315.592.9+539.26; 535.37; 537.531.2. metalloporphyrins; nanocomposites; fullerenes; photoluminescence; X-ray radiation; scanning electron microscopy; X-ray diffractometry https://physmath.spbstu.ru/article/2018.40.3/ 03_26-40_11(2)2018.pdf

RAR RUS 41-48 Romanov Nikolay nikromanov.90@gmail.com Peter the Great St. Petersburg Polytechnic University Musikhin Sergey musihin.sf@spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Gamma-induced effect on the luminescence of nanocomposites of MEH-PPV conductive polymer with lead sulphide quantum dots Gamma radiation effect on the photoluminescence of thin films of conductive polymer MEH-PPV, PbS quantum dots (QDs) and MEH-PPV–PbS (QDs) nanocomposite have been studied. Thin films were obtained by centrifugation. Samples were irradiated with exposure doses (in Gy): 0; 1,84·104; 4,18·104; 6,73·104. Photoluminescence of the polymer MEH-PPV was established to change nonmonotonically with an increase in doses, which might be due to running the oppositely directed, competing processes under the action of gamma quanta, namely destruction and cross-linking of polymer chains. Significant polymer’s restructuring took place under gamma-rays. Photoluminescence intensity of PbS QDs fell approximately twofold after irradiation with doses mentioned above, the intensity maximum shifting to the short-wavelength region. This behavior was due to a change in the energy structure of the QDs. The effect of gamma quanta on the QDs photoluminescence was analyzed. 10.18721/JPM.11204 535.37 54-78 539.2 541.65/.654 conductive polymer quantum dot MEH-PPV PbS photoluminescence gamma quantum https://physmath.spbstu.ru/article/2018.40.4/ 04_41-48_11(2)2018.pdf

RAR RUS 49-60 Zaborova Dariya zaborova-dasha@mail.ru Peter the Great St. Petersburg Polytechnic University Petrichenko Mikhail fonpetrich@mail.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Musorina Tatiana flamingo-93@mail.ru The Dupuis paradox and mathematical simulation of unsteady filtration in a homogeneous closing dike The aim of this study is to determine a flow rate and a shape of a depression curve in conditions of filtration through a rectangular closing dike using aperiodic solutions of the Boussinesq limit problem. We established that the formation of this curve and the seepage area (the final jump of continuity or interruption of the curve at the minimum pressure point) on the border of the downstream and porous medium, in the closing dike of finite length, occurs for a finite amount of time proportional to the square of the closing dike length. Therefore, in the short closing dike, a cut-out point does not have time to fall into the downstream during the time, it takes for the depression curve to touch the water level in the upstream. The continuous curve without seepage area always reaches the steady state in the semi-infinite closing dike for a finite amount of time. 10.18721/JPM.11205 626 filtration of subsoil water porous medium depression curve seepage area https://physmath.spbstu.ru/article/2018.40.5/ 05_49-60_11(2)2018.pdf

RAR RUS 61-72 Sobolev Institute of Mathematics Anikonov Dmitriy anik@math.nsc.ru Sobolev Institute of Mathematics Konovalova Dina dsk@math.nsc.ru Direct and inverse problems for a wave equation with discontinuous coefficients The present article is devoted to the studies in solutions of partial differential equations with discontinuous coefficients for the highest derivatives. This line of investigation is not only of purely academic interest for mathematicians, but plays an important part in the theory of sounding of unknown media composed of various substances. The direct and inverse problems have been considered. The theorem of existence and of the solution-uniqueness was proved for the first of them. For inverse problems, the uniqueness of the solution was proved.The integro-differential equation, which is a consequence of the physical laws, was used for solving the direct problem in the derivation of formulae. The meaning of inverse problems lies in determination of a junction point of different materials and a wave velocity. The used nature of the proof allows us to construct an appropriate numerical algorithm. 10.18721/JPM.11206 517.946 differential equation discontinuous coefficient sounding of unknown media direct and inverse problems https://physmath.spbstu.ru/article/2018.40.6/ 06_61-72_11(2)2018.pdf

RAR RUS 73-83 Peter the Great St. Petersburg Polytechnic University Korenyugin Dmitriy polarisdk@mail.ru Ioffe Institute Martsinovsky Artemiy amartsinovsky@gmail.com

St. Petersburg, Russian Federation

An asymmetrical dielectric barrier discharge in the pulsed mode The paper presents the results of an investigation of an asymmetric dielectric barrier discharge (DBD) in the air at atmospheric pressure. The discharge system consisted of a plane electrode and semispherical short-radius one, and the both were coated with dielectric. The discharge was excited by a train of almost sinusoidal damped oscillations which was applied to electrodes with a frequency of 1 kHz. It has been found that the preferable to biological applications homogeneous avalanche form of the DBD is always realized in the investigated voltage range 7 – 15 kV, whereas the streamer form of the discharge is excited under identical conditions in the case of a conducting semisphere. It was also established that the positive and negative (according to the voltage sign of the first pulse of the train onto the small electrode) discharge differ greatly in their characteristics. An explanation for this difference has been proposed. 10.18721/JPM.11207 533.9 dielectric barrier discharge pulse train avalanche streamer form discharge mode https://physmath.spbstu.ru/article/2018.40.7/ 07_73-83_11(2)2018.pdf

RAR RUS 84-95 Kozhevnikov Vadim vadim.kozhevnikov@gmail.com 7006335646 Peter the Great St. Petersburg Polytechnic University Privalov Vadim kafedra@physics.spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

The geometrical effect of an active element cross-section on the laser gain An improved method for calculating the dependence of a laser emission gain on the tube cross-section’s geometry has been developed. In this connection the general solution of the Helmholtz equation was considered. But the solution in the form of an infinite series holds the potential for errors. In practice, a researcher has to replace the infinite series by a finite one. Some measures for solving the problems arising in this case were proposed. We have obtained an approximate solution of the Helmholtz equation that is convenient for practice, and a modified method for finding the coefficients of expansion has been developed. The method was tested for some cross-sectional forms that allowed independent theoretical calculation. As a result, the calculations accuracy was demonstrated to improve. 10.18721/JPM.11208 621.373. laser,active element laser radiation gain geometry of a tube cross-section https://physmath.spbstu.ru/article/2018.40.8/ 08_84-95_11(2)2018.pdf

RAR RUS 96-105 Borisova Margarita Kamalov Almaz 1.almaz.kamalov@gmail.com Orlov Ivan ivaorlov@yandex.ru Smirnova Valentina ves@hq.macro.ru Charge relaxation in partially crystalline R-BAPB polyimides under conditions of elevated humidity The charge relaxation processes in the films based on R-BAPB polyimide with different degree of crystallinity have been studied. The supramolecular structure effect on the charge relaxation processes in the films under elevated humidity conditions was revealed. The obtained experimental data was analyzed in the context of the present-day knowledge of the charge relaxation mechanism. The complex spectra of the thermally stimulated depolarization currents (TSDC) were resolved into individual components and described by the first-order kinetics equations using computer simulation. The TSDC activation energies were calculated and interpreted in terms of the mechanism of release of charge carriers. It was shown that the increment of crystallinity degree of the polyimide films lead to a decrease in the electret state stability at elevated temperature and high humidity. 10.18721/JPM.11209 621.315 polyimide crystallinity hygroscopicity trap simulation coronoelectret https://physmath.spbstu.ru/article/2018.40.9/ 09_96-105_11(2)2018.pdf

RAR RUS 106-118 0000-0002-8499-8650 Ioffe Institute of RAS Pakhotin Vladimir v.pakhotin@mail.ioffe.ru Zakrevskii Vladimir v.zakrevsky@mail.ioffe.ru Peter the Great St. Petersburg Polytechnic University Sudar Nikolai sudar53@mail.ru Apaseyev Aleksey aapaseev@bk.ru The ion emission during the fracture of polymers The results of the study of charged particle emission in the course of the rupture of polymer film samples in the high vacuum have been presented. Regularities of ion emission at the last stages of the stretching are associated with peculiarities of the main crack’s intergrowing. Calculations of ion-motion trajectories within the crack were carried out. It was established that the ions emitted from the crack tip on the sample surface were recorded experimentally while the crack growing. The emitting region size and the emission current level were estimated. Mechanisms of formation of low-molecular ions during polymer fracture were discussed. 10.18721/JPM.11210 53.539.4; 53.537.58 emission ion mechanoemission ionization of macromolecules crack https://physmath.spbstu.ru/article/2018.40.10/ 10_106-118_11(2)2018.pdf

RAR RUS 119-129 Radzevich Pavel radzevichp@gmail.com Peter the Great St. Petersburg Polytechnic University Berdnikov Alexander alexber@phmf.spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

0000-0003-0309-5917 Peter the Great St. Petersburg Polytechnic University Berdnikov Yaroslav berdnikov@spbstu.ru Zharko Sergey zharkosergey94@gmail.com 0000-0002-3395-0454 Peter the Great St. Petersburg Polytechnic University Kotov Dmitry dmitriy.kotov@gmail.com PHENIX experiment: study of the jet quenching effect in the ultrarelativistic U + U collisions Extensive study of heavy ion collisions at RHIC has resulted in discovery of a new state of matter – strongly interacting quark-gluon plasma (sQGP). Measurements of high-pT particles contribute to systematic study of sQGP properties. Yields of leading particle such as π0 can be measured with high precision at high transverse momenta. Study of π0 in different collision systems allows investigation of the path length dependence of energy loss in the medium. U+U presents an opportunity to research non-spherical heavy ion collision system with highest energy density in central collisions. This paper presents the most recent PHENIX results on π0 production in U+U collision system. Results are presented as functions of pT and centrality. 10.18721/JPM.11211 539.126.3 quark gluon plasma nuclear modification factor jet quenching heavy ion collision https://physmath.spbstu.ru/article/2018.40.11/ 11_119-129_11(2)2018.pdf

RAR RUS 130-138 Dikiy Dmitriy diwil@mail.ru Akimov Valeriy valeri_akimov@mail.ru Sochava Alexander sochava@radio.rphf.spbstu.ru 7006360562 Peter the Great St. Petersburg Polytechnic University Cherepanov Andrey hsapst@spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

Phase shift control using waveguide-slot phase shifter Some specific electrical properties of a waveguide-slot phase shifter have been studied in the paper. We propose to use waveguide-slot phase shifter as a controlled coupler in the switchgears of phased arrays with series feeding and p–i–n-diodes control. The characteristics of the waves transmitted through the waveguide and their dependences on the slot’s position and dimensions were considered. The slot of special form was cut through the waveguide wide wall. We succeeded in obtaining the phase shift up to 360 degrees by the lengthwise variation in the slot’s position in a coupling window and by the slot’s displacement specularly relative to the waveguide’s axis line. The study of the problem was conducted experimentally and by simulation technique. The simulation results were verified by experimental data. The proposed phase-shifter can be also used in switchgears of phased arrays with a locked beam. 10.18721/JPM.11212 29.35.23 waveguide slot in waveguide antenna phased array phase shifter https://physmath.spbstu.ru/article/2018.40.12/ 12_130-138_11(2)2018.pdf

RAR RUS 139-150 Agapev Kirill cyr96@mail.ru M-5766-2013 57192222016 0000-0002-3584-4583 Peter the Great St. Petersburg Polytechnic University Ivanov Vadim ivanov_vk@spbstu.ru

Russia, 195251, St.Petersburg, Polytechnicheskaya, 29

MBN Research Center at Frankfurt Innovation Center of Biotechnology Korol Andrei korol@mbnexplorer.com

Frankfurt am Main, Germany

7003387326 0000-0003-1602-6144 MBN Research Center at Frankfurt Innovation Center of Biotechnology Solov'yov Andrei solovyov@mbnresearch.com

3 Altenhöferallee, Frankfurt am Main, 60438, Germany

Channeling of ultrarelativistic particles in a diamond crystal The numerical simulation results on the channeling of ultra-relativistic electrons and positrons with the energy of 270 MeV in a diamond crystal are presented in the paper. Using the pack of applied codes MBN Explorer [1, 2], the trajectories of the charged particles have been determined for the particles’ falling on the 20 μm-length crystal, along (110) crystallographic plane. The channeling parameters and radiation spectra of electrons and positrons were obtained computationally for the cases of the charged particles’ incidence on a straight diamond crystal and a periodically bent one. 10.18721/JPM.11213 538.911; 539.1.03 periodically bent diamond crystal channeling ultrarelativistic particle channeling radiation https://physmath.spbstu.ru/article/2018.40.13/ 13_139-150_11(2)2018.pdf

RAR RUS 154-164 Gusakov Andrey a.gusakov.spb@mail.ru Grekov Mikhail grekov66@yandex.ru Seroshtanov Vladimir vladvik1992@gmail.com Aerodynamics and heat transfer on the surface of a single сircular fin In the paper, it has been proposed to unite the heat flux measurements with thermal imaging and the PIV diagnostics for studies in aerodynamics and heat transfer at the surface of a circular fin. The hollow fin under consideration was heated by saturated steam from within; meanwhile the isothermal external surface simulated an ideal fin. The surface flow and heat transfer of the solid fin sized and shaped identically, and made of titanium alloy, was investigated in the same regimes. Gradient heat flux sensors were placed on the fin surface. The velocity field near the fin, the temperature field and the heat flux per unit area at its surface were obtained. The data analysis gave an impartial piece of information. The proposed method allows examination of a flow and a heat transfer on the fin surface in the real-time processing. 10.18721/JPM.11214 536.2 heat flux measurement PIV diagnostics circular fin heat flux heat transfer coefficient https://physmath.spbstu.ru/article/2018.40.14/ 14_151-164_11(2)2018.pdf