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Your search keyword '"Uvarov, I."' showing total 120 results
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120 results on '"Uvarov, I."'

4. A way to measure the dispersion forces near the van der Waals-Casimir transition

Author

Svetovoy, V. B., Postnikov, A. V., Uvarov, I. V., Stepanov, F. I., and Palasantzas, G.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

Forces induced by quantum fluctuations of electromagnetic field control adhesion phenomena between rough solids when the bodies are separated by distances ~10nm. However, this distance range remains largely unexplored experimentally in contrast with the shorter (van der Waals forces) or the longer (Casimir forces) separations. The reason for this is the pull-in instability of the systems with the elastic suspension that poses a formidable limitation. In this paper we propose a genuine experimental configuration that does not suffer from the short distance instability. The method is based on adhered cantilever, whose shape is sensitive to the forces acting near the adhered end. The general principle of the method, its possible realization and feasibility are extensively discussed. The dimensions of the cantilever are determined by the maximum sensitivity to the forces. If the adhesion is defined by strong capillary or chemical interactions, the method loses its sensitivity. Special discussion is presented for the determination of the minimum distance between the rough solids upon contact, and for the compensation of the residual electrostatic contribution. The proposed method can be applied to any kind of solids (metals, semiconductors, dielectrics) and to any intervening medium (gas or liquid)., Comment: 27 pages, 8 figures, to be published in Phys. Rev. Applied

Published
2020

6. Highly energetic phenomena in water electrolysis

Author

Postnikov, A. V., Uvarov, I. V., Lokhanin, M. V., and Svetovoy, V. B.

Subjects
Condensed Matter - Soft Condensed Matter, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Fluid Dynamics
Abstract

Water electrolysis performed in microsystems with a fast change of voltage polarity produces optically invisible nanobubbles containing H2 and O2 gases. In this form the gases are able to the reverse reaction of water formation. Here we report extreme phenomena observed in a millimeter-sized open system. Under a frequency of driving pulses above 100 kHz the process is accompanied by clicking sounds repeated every 50 ms or so. Fast video reveals that synchronously with the click a bubble is growing between the electrodes which reaches a size of 300 um in 50 us. Detailed dynamics of the system is monitored by means of a vibrometer by observing a piece of silicon floating above the electrodes. The energy of a single event is estimated as 0.3 uJ and a significant part of this energy is transformed into mechanical work moving the piece. The observations are explained by the combustion of hydrogen and oxygen mixture in the initial bubble with a diameter of about 40 um. Unusual combustion mechanism supporting spontaneous ignition at room temperature is responsible for the process. The observed effect demonstrates a principal possibility to build a microscopic internal combustion engine., Comment: 9 pages, 5 figures; Supplementary Information at http://www.nature.com/articles/srep39381

Published
2017
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8. Relativistic oscillator model with spin for nucleon resonances

Author

Kulikov, D. A., Uvarov, I. V., and Yaroshenko, A. P.

Subjects
High Energy Physics - Phenomenology, Nuclear Theory
Abstract

The relativistic three-body problem is approached via the extension of the SL(2,C) group to the Sp(4,C) one. In terms of Sp(4,C) spinors, a Dirac-like equation with three-body kinematics is composed. After introducing the linear in coordinates interaction, it describes the spin-1/2 oscillator. For this system, the exact energy spectrum is derived and then applied to fit the Regge trajectories of baryon N-resonances in the (E^2,J) plane. The model predicts linear trajectories at high total energy E with some form of nonlinearity at low E., Comment: 13 pages, 2 figures, 1 table

Published
2011
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11. Performance Calculation for a MEMS Switch with a Floating Electrode.

Author

Morozov, M. O. and Uvarov, I. V.

Subjects
*INSERTION loss (Telecommunication), *BOROSILICATES, *ELECTRODES, *ELECTRIC capacity
Abstract

Switches fabricated using MEMS technology are considered as a promising element base of radio electronics. The main characteristic of a MEMS switch is the ratio of capacitances in the closed and open states. For conventional devices, this ratio is of several units, but it can be significantly increased by implementing original design solutions. This paper studies the switch, which is a combination of capacitive and resistive devices. Its working characteristics are considered depending on the substrate properties and contact resistance. The switch provides a capacitance ratio of 27.7 and 46.1 when using sapphire and borosilicate glass substrates, while high-resistivity silicon does not allow attaining values above 7.4 due to the high parasitic capacitance. The isolation and insertion loss are 14.7–19.4 and 0.8–1.1 dB in the frequency range of 4–10 GHz on a sapphire wafer. Acceptable S-parameters are achieved when the contact resistance is not higher than 1 Ω. [ABSTRACT FROM AUTHOR]

Published
2023
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30. High concentration of H2 and O2 nanobubbles in water electrolytes and their collective optical effect

Author

Postnikov, A. V., Uvarov, I. V., Lokhanin, M. V., Svetovoy, V. B., Perova, Tatiana, and Nanostructured Materials and Interfaces

Subjects
Electrolysis, Supersaturation, Materials science, Hydrogen, Electrolysis of water, Analytical chemistry, chemistry.chemical_element, Nanotechnology, Electrolyte, Oxygen, law.invention, chemistry, law, Electrode, Laplace pressure
Abstract

Water electrolysis with a fast change of the polarity pumps in the liquid a huge amount of hydrogen and oxygen gases. In contrast with the DC electrolysis the gases do not form visible bubbles but change significantly the refractive index of the liquid nearby the electrodes from n = 1.35 to the values smaller than 1.19. The decrease of n is registered as distortion of the images of the electrodes. We argue that all the gas is collected in H2 and O2 nanobubbles with a size smaller than 200 nm. The concentration of nanobubbles with a size of 100 nm is estimated as 1021 m-3. Due to a significant contribution from the Laplace pressure the effective supersaturation reaches 500 for hydrogen and 150 for oxygen.

Published
2017

47. VEGA-CONSTELLATION TOOLS TO ANALIZE HYPERSPECTRAL IMAGES

Author

Savorskiy, V., primary, Loupian, E., additional, Balashov, I., additional, Kashnitskii, A., additional, Konstantinova, A., additional, Tolpin, V., additional, Uvarov, I., additional, Kuznetsov, O., additional, Maklakov, S., additional, Panova, O., additional, and Savchenko, E., additional

Published
2016
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