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Baryshnikov S.V.,Amur State University | Milinskiy A.Y.,Amur State University | Charnaya E.V.,Saint Petersburg State University | Bugaev A.S.,Moscow Physical Technical Institute | Samoylovich M.I.,Moscow Institute of Physics and Technology
Ferroelectrics | Year: 2016

Dielectric studies were carried out for the ammonium hydrogen sulphate, NH4HSO4, nanopartiles confined to three different mesoporous silica matrices: opal (photonic crystal), porous glass (mean pore size of 7 nm), and SBA-15 molecular sieves (pore size of 7.5 nm). Measurements were made within a temperature range 100 to 300 K which covers two structural phase transitions bounded the intermediate ferroelectric phase. The temperature of the upper second order phase transition was found not to shift compared to that in bulk. The lower phase transition shifted compared to bulk leading to the expansion of the ferroelectric phase. The transition temperature reduction, diffusion of transitions, and width of the thermal hysteresis differed for different nanocomposites and did not correlate to the pore size. The experimental data were treated within the framework of the models developed for isolated small ferroelectric particles and arrays of coupled particles. The rise of the space charge polarization effects was also observed. © 2016 Taylor & Francis Group, LLC.

Sakovich R.A.,Moscow Physical Technical Institute | Polyak B.M.,Research Institute of Physicochemical Medicine 1a | Gularyan S.K.,RAS Semenov Institute of Chemical Physics | Romanov A.N.,Moscow State University | Svetlichnyi V.Yu.,Research Institute of Physicochemical Medicine 1a
Russian Chemical Bulletin | Year: 2013

The quantum chemical simulation of the ground and electron-excited states of diverse complexes of fluorescent probe 4-dimethylaminochalcone (DMAC) and water in vacuo was performed by the HF/MP2 and RI-CC2 methods. Molecules of the DMAC probe and water can form five types of stable complexes. The geometries corresponding to the potential energy minimum and dipole moments for two lowest singlet and one lowest triplet states were calculated for each type of the complexes. The partial charges on the DMAC atoms and their changes due to the intramolecular charge transfer upon photoexcitation were determined. The coordination of the water molecule at the carbonyl group of DMAC is preferable in vacuo. The formation of hydrogen bonds between the carbonyl group of DMAC and water molecules decreases the energy of the excited state of the complex 1(π, π*), due to which the fluorescence yield increases upon photoexcitation. The calculation results are confirmed by the experimental data on studying the fluorescence of the probe in binary mixtures of benzene and alcohols. © 2013 Springer Science+Business Media New York.

Larchenkova T.,RAS Lebedev Physical Institute | Lutovinov A.,Space Research Institute | Lyskova N.,Moscow Physical Technical Institute
Proceedings of the International Astronomical Union | Year: 2010

The jets image modelling of gravitationally lensed sources have been performed. Several basic models of the lens mass distribution were considered, in particular, a singular isothermal ellipsoid, an isothermal ellipsoid with the core, different multi-components models with the galactic disk, halo and bulge. The obtained jet images were compared as with each other as with results of observations. A significant dependence of the Hubble constant on the model parameters was revealed for B0218+357, when the circular structure was took into account. © International Astronomical Union 2011.

Astapenko V.A.,Moscow Physical Technical Institute | Mutafyan M.I.,Centennial College
Russian Physics Journal | Year: 2012

The present work is devoted to investigation of photoionization of acceptor centers in diamond upon exposure to ultrashort electromagnetic pulses (USP) in the limit of perturbation theory. Calculations are performed for Gaussian USP with controllable phase parameters based on an analytical expression for the total photoionization probability during the time over which the pulse acts. Dependences of the photoionization probability on the USP characteristics are investigated, including pulse duration, carrier-envelope phase, and chirp frequencies. It is demonstrated that changing the USP parameters, the distribution function of charge carriers in the valence band of the diamond can be manipulated. © 2012 Springer Science+Business Media, Inc.

Bulychev N.A.,RAS Lebedev Physical Institute | Morozova E.A.,RAS A.M. Prokhorov General Physics Institute | Muravyev E.N.,Russian Academy of Sciences | Chernov A.A.,Moscow Physical Technical Institute | Kazaryan M.A.,RAS Lebedev Physical Institute
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2015

In this paper, a new form of plasma discharge in a liquid under intensive ultrasonic treatment exceeding the cavitation threshold has been explored in view of initiation of various physical and chemical processes. Furthermore, in this plasma discharge, nanoparticles of oxides of various metals with controlled shape and size of particles and narrow particles size distribution have been synthesized. Further research proved that ultrasonic cavitation during synthesis significantly affects the physical and chemical characteristics of nanoparticles. These nanoparticles can be used for formation of nanostructured coatings on surfaces of various materials by an ultrasonic technique. © 2016 SPIE.

Astapenko V.A.,Moscow Physical Technical Institute
Russian Physics Journal | Year: 2011

Within the limits of a new approach based on the Mie scattering theory, polarization bremsstrahlung radiation (PBR), arising during electron scattering on a metallic nanosphere with radius from 10 to 100 nm placed in a dielectric medium is theoretically investigated. The spectral range close to the plasmon resonance is considered, where the contribution of the polarized channel to bremsstrahlung radiation dominates. Spectral, velocity, and angular PBR characteristics are calculated. The sensitivity of the PBR spectrum to the dielectric permittivity of the medium surrounding the nanosphere is demonstrated. © 2011 Springer Science+Business Media, Inc.

Astapenko V.A.,Moscow Physical Technical Institute | Sakhno S.V.,Moscow Physical Technical Institute
Russian Journal of Physical Chemistry B | Year: 2016

The photoionization of the C60 and C240 fullerenes by ultrashort electromagnetic pulses of subfemtosecond duration is studied. The probability for the process to occur during the action of the pulse as a function of the pulse duration is calculated for different carrier frequencies. The spectrum of photoelectrons emitted during the ionization of the fullerenes by a pulse with a corrected Gaussian shape is calculated. © 2016, Pleiades Publishing, Ltd.

Dem'Yanov A.Y.,Moscow Physical Technical Institute | Dinariev O.Y.,Moscow Scientific Center Shlyumberzhe | Ivanov E.N.,Moscow Scientific Center Shlyumberzhe
Journal of Engineering Physics and Thermophysics | Year: 2012

The problem on the transfer of a three-phase water-gas-oil mixture in a porous medium was solved for the case where the water contains a fine-disperse gas phase in the form of microsized or nanosized bubbles. It was suggested that the transfer of bubbles is mainly due to the flow of the disperse phase (water). In this case, the large aggregates of the gas phase in the porous space, in the water, and in the oil are transferred in accordance with the modified Darcy law for multiphase mixtures. A mathematical model of movement of the indicated mixture has been constructed for the case where the main phases (water, gas, and oil) adhere to the filtration equations and the fine-disperse gas phase is defined by a kinetic equation like the Boltzmann equation. Some one-dimensional numerical solutions of the indicated problem were analyzed. © 2012 Springer Science+Business Media New York.

Yakovenko G.N.,Moscow Physical Technical Institute
Automation and Remote Control | Year: 2011

In this paper, robust mathematical models of real-life processes are discussed. Robustness testifies itself not only in the parametric uncertainty setup, but also because the parameters can be thought of as sufficiently arbitrary functions of the independent variables (so-called nonstationary robustness). Control systems can be considered as specific cases of this situation. Nonstationary robustness is studied for the Lotka-Volterra predator-prey model and its modification. © Pleiades Publishing, Ltd., 2011.

Astapenko V.A.,Moscow Physical Technical Institute | Baturin A.S.,Moscow Physical Technical Institute | Korostylev E.V.,Moscow Physical Technical Institute
Journal of Surface Investigation | Year: 2010

This work is devoted to theoretical and experimental investigation of the bremsstrahlung (BrS) spectrum of electrons with an energy of 10-30 eV scattered in a copper plate. Modeling of the photon yield from a target has been carried out taking into account the polarization BrS channel, elastic and inelastic electron scattering by medium atoms, photon absorption in the target material, and coherent effects when electrons interact with a polycrystalline structure of metal. An FEI Quanta 200 scanning electron microscope with a supplement for X-ray microanalysis was used. Good agreement between experimental and theoretical results has been obtained. © Pleiades Publishing, Ltd., 2010.

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