Персона:
Акишев, Юрий Семенович

Организационные подразделения

Организационная единица

Институт лазерных и плазменных технологий

Стратегическая цель Института ЛаПлаз – стать ведущей научной школой и ядром развития инноваций по лазерным, плазменным, радиационным и ускорительным технологиям, с уникальными образовательными программами, востребованными на российском и мировом рынке образовательных услуг.

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Акишев

Имя

Юрий Семенович

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Теперь показываю 1 - 10 из 10

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Effect of the speed of the flat substrate movement on the air plasma jet transversal spreading at its impinging the surface
(2020) Balakirev, A. A.; Medvedev, M. A.; Petryakov, A. V.; Trushkin, N. I.; Akishev, Yu. S.; Акишев, Юрий Семенович
© 2020 Published under licence by IOP Publishing Ltd.Low-temperature plasma jets are used to treat both the motionless and moving objects (targets or substrates). The gas-dynamic aspects of the plasma jet's interaction with the target are important and have to be taken into account in selecting the most efficient plasma processing parameters. Clearly, the spreading of plasma jet over a fast-moving surface is significantly different from its spreading over a fixed target. This question is investigated by the example of the interaction of an air plasma jet with a surface of fast-rotating dielectric disk. It is shown the change in the shape of the jet striking perpendicularly the moving substrate happens due to the movement of a thin layer of the ambient air adjacent to the fast-moving surface. This effect can have a noticeable influence on the reactive particles transfer from the plasma jet onto the surface to be treated.
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Relation of electric conditions between a source of Ar plasma jet and a substrate with a configuration of a plasma sheet on a target
(2019) Balakirev, A. A.; Karalnik, V. B.; Petryakov, A. V.; Trushkin, N. I.; Akishev, Yu. S.; Акишев, Юрий Семенович
© Published under licence by IOP Publishing Ltd.The paper presents the experimental results relevant to the external electrical influence on the structure of a thin plasma sheet formed atop a substrate surface by Ar plasma jet that is being generated by a coaxial sinusoidal barrier discharge (BD) in an argon flow. The electrical influence on the target is being created due to connecting of a high-voltage or grounded electrode of the BD to the metal plate on which the dielectric or metallic substrate to be treated is located. Such an approach ensures a synchronism of the interaction of the external auxiliary electric field with the own electric field of the ionization wave (plasma bullet) propagating along the argon plasma jet toward the substrate during each period of the BD alternating voltage. An image of the structure of the plasma sheet on the substrate surface averaged over many periods of sinusoidal voltage was recorded in the experiments.
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Dielectric barrier discharge in radially converging gas flow generating two coaxial and opposite directed nonthermal plasma jets
(2020) Petryakov, A. V.; Trushkin, N. I.; Akishev, Y. S.; Акишев, Юрий Семенович
© 2020 Institute of Physics Publishing. All rights reserved.An original source of non-equilibrium low-temperature plasma jets based on a barrier discharge in a radially converging flow of atomic and molecular gases at atmospheric pressure was developed and created. The discharge electrode system consists of two parallel and coaxial quartz disks, in the geometric center of those two coaxial identical holes were made. On the outer side of each disk a metal foil in the form of a wide ring is glued coaxially to the holes. The gas flow is directed from the periphery of the disks to their center and exits normally to the disks surfaces through narrow holes. As a result, two coaxial and opposite directed plasma jets are formed, which are perpendicular to the disks. There are no analogs of the developed source in literature. The source has been tested for plasma treatment of dielectric yarns that are transported through holes in dielectric barriers and are constantly enveloped in plasma jets. The results show practical possibility of using the developed gas-discharge source for continuous "roll-to-roll" plasma treatment of polymer filaments with the aim to improve their hydrophilicity.
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Impact of the pre-deposited surface charge on the breakdown in a dielectric barrier discharge in the air
(2020) Karalnik, V.; Petryakov, A.; Shao, T.; Zhang, C.; Akishev, Y.; Акишев, Юрий Семенович
© 2020 Published under licence by IOP Publishing Ltd.The electrical charge deposited on a dielectric barrier of dielectric barrier discharge (DBD) changes markedly the configuration and strength of the local electric field both on the barrier and in the gas gap. In turn, a change in the local electric field affects the rate of ionization multiplication of electrons in this area and, accordingly, influences the breakdown conditions providing the appearance of microdischarges in a barrier discharge. The features of the DBD breakdown in the presence of the pre-deposited charge on a dielectric barrier were investigated by the example of the plane-to-plane DBD operating in the ambient air at atmospheric pressure. The electric charge deposition on the barrier was performed in advance with the use of the pulsed pin-to-plane barrier corona. Corona discharge allows one to control both the amount and location of the pre-deposited charge. The slow increasing voltage of the needed polarity was used to initiate the breakdown in the plane-to-plane DBD. The slow increasing applied voltage provides the multiple breakdowns forming the "one by one"sequence of MDs. The analysis of the obtained results was performed on the base of the conception of the necessary and sufficient conditions for the MDs formation.
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Influence of the sign and magnitude of a surface charge on the breakdown voltage of a barrier corona discharge in Ar
(2019) Balakirev, A. A.; Medvedev, M. A.; Petryakov, A. V.; Trushkin, N. I.; Akishev, Y. S.; Акишев, Юрий Семенович
© Published under licence by IOP Publishing Ltd.The topic of this article is related to the breakdown phenomena in the surface dielectric barrier discharge (SDBD). The surface charge, locally deposited on the dielectric barrier, changes markedly the configuration and intensity of the electric field both on the barrier and in the gas gap. In turn, a change in the local electric field affects the rate of ionization multiplication of electrons in this area and, accordingly, influences the breakdown conditions of both volume and surface barrier discharges. In the case of sinusoidal SDBD, the first breakdown in each next half-cycle will be controlled by the charge deposited on the barrier during the previous half-cycle. Contrariwise, if there are several successive breakdowns in the half-cycle, each next breakdown after the first one will be controlled predominantly by the charge and plasma created by the previous breakdown in this half-cycle but not only by the charge deposited in the previous half-cycle. These features of the SDBD breakdown were investigated by the example of the barrier corona in argon at atmospheric pressure in the pinto-plane configuration. This discharge allows us the controlling of the location of the deposited charge. Surface charge was deposited in advance and by the SDBD itself.
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Numerical simulation of streamer spreading over the water surface
(2019) Balakirev, A.; Karalnik, V.; Petryakov, A.; Trushkin, N.; Akishev, Y.; Акишев, Юрий Семенович
© Published under licence by IOP Publishing Ltd.The 2D mathematical model of a streamer in a surface barrier discharge is presented. The discharge was created in nitrogen at atmospheric pressure. The barrier, which can be a dielectric, tap or distilled water, covers a grounded electrode. A pulse voltage of-15 kV with a leading edge of 10 ns is applied to the cathode located above the barrier surface. Calculations of the propagation of a volume streamer from the cathode to the barrier and the surface streamer along the barrier were carried out. The results of calculations show that the discharge current increases at the stage of propagation of a volume streamer and decreases at the stage of propagation of a surface streamer.
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Spectroscopic determination of the composition and spatial distribution of active particles in a plasma jet of helium and argon being blown out into atmospheric air
(2020) Karalnik, V. B.; Petryakov, A. V.; Trushkin, N. I.; Akishev, Y. S.; Акишев, Юрий Семенович
© 2020 Institute of Physics Publishing. All rights reserved.Optical emission spectroscopy was used to determine the composition and spatial distribution of reactive species along a non-thermal plasma jet in a stream of argon and helium, expanding in the ambient air. It was shown that the composition and spatial distribution of reactive species in argon and helium plasma jets differ significantly. The geometric dimensions of the Ar and He plasma jets are also noticeably different. The features of the observed patterns of the composition and spatial distribution of active particles are discussed.
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Influence of different processes of the electron emission on the ultrahigh charging of a dust particle in plasma by the energetic e-beam.
(2019) Balakirev, A. A.; Karalnik, V. B.; Petryakov, A. V.; Trushkin, N. I.; Akishev, Yu. S.; Акишев, Юрий Семенович
© Published under licence by IOP Publishing Ltd.Results of numerical modeling of dynamics of ultrahigh charging of the dust particle surrounded with plasma and irradiated by an electron beam with high electron energy are given in the presented work. The e-beam was created by the pulsed open discharge in strongly overvoltage regime.The maximum negative charge accumulated on the irradiated particle is defined by the intensity of processes of charging and discharging of a target. In general, the process of charging is defined by e-beam parameters (its energy and the current density) while the discharging of a target depends on many processes, such as delivery of positive ions from the plasma onto a negatively charged target and also an emission of electrons from a target surface. In its turn, the electron emission from a surface is caused by the various processes including kinetic emission of electrons due to impact of the target by fast ions, secondary electron emission by e-beam, thermo-emission and auto-emission of electrons in case of strong heating of a particle and emergence of the strong electric field on a surface of the highly charged target. The ultrahigh charging of the dust particle irradiated by an e-beam with the energy of 25 keV was modeled. Results of numerical calculations about influence of the listed above discharging processes of a target on its maximum negative charge and potential have shown that the greatest contribution to the target discharging process belongs to the kinetic electron emission caused by fast positive ions.
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Gas-dynamic structure of a plasma jet in He and Ar, striking the surface of a liquid and a plane dielectric
(2020) Kopiev, V. F.; Kopiev, V. A.; Inshakov, S. I.; Kudryavtseva, E. D.; Akishev, Yu. S.; Акишев, Юрий Семенович
© 2020 Published under licence by IOP Publishing Ltd.The results of experiments on the interaction of an argon plasma jet with a liquid are presented. The effect of a coaxial barrier discharge on the gas-dynamic regime of a plasma jet of helium, freely blown into ambient air, and also colliding with a solid surface, is studied. Three orientation helium jets were studied-the jet is directed up, down and horizontally. Schlieren images of a jet were compared with visible images of a plasma jet. It is concluded that the main effect of the discharge on the gasdynamic regime of the jet is associated with gas heating in the discharge zone.
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The ionization waves propagation in a long capillary dielectric tube in the absence of surface charge
(2020) Balakirev, A. A.; Karalnik, V. B.; Medvedev, M. A.; Petryakov, A. V.; Akishev, Yu. S.; Акишев, Юрий Семенович
© 2020 Published under licence by IOP Publishing Ltd.The initiation of the electrical breakdown in a narrow tube filled with a gas under reduced pressure requires the voltage higher compared to that for a much broader tube. Besides, at the fixed applied voltage formally sufficient for breakdown, the probability for the breakdown happening in a narrow tube is far from 100%. This probability can be increased appreciably if to organize the surface ionization waves preceding the volume breakdown in a narrow tube. The breakdown development in a long capillary dielectric tube induced by the surface ionization waves was investigated in this work. The experiments were carried out with the use of a quartz capillary tube with a high aspect ratio of length to diameter. The tube was filled with helium at pressures of 1-30 Torr. The pre-posited surface charge on the tube wall was absent. It has been found the completed high-current breakdown between two electrodes located at the ends of the long capillary tube develops with a high probability with the presence of surface ionization waves within the tube.