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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. Source


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. Source


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. Source


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. Source


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. Source

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