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Aliev M.A.,Institute of Biochemical Physics
Modern Physics Letters B | Year: 2015

The analytical expressions have been obtained to describe the dependence of spinodal curve at which isotropic state of polydisperse melt of semiflexible diblock copolymer becomes unstable with respect to formation of nematic state on the polydispersity indices of the blocks, parameters of anisotropic interactions, and flexibility of blocks. The flexibility of blocks is taken into account within discrete worm-like chain model, lengths of blocks are assumed to be distributed by the Schulz-Zimm distribution. It is shown that increase of degree of polydispersity of blocks yields the increase of nematic spinodal temperature. © 2015 World Scientific Publishing Company. Source

Zabrodin A.,Institute of Biochemical Physics
Complex Analysis and Operator Theory | Year: 2010

The partition function for a canonical ensemble of 2D Coulomb charges in a background potential (the Dyson gas) is realized as a vacuum expectation value of a group-like element constructed in terms of free fermionic operators. This representation provides an explicit identification of the partition function with a tau-function of the 2D Toda lattice hierarchy. Its dispersionless (quasiclassical) limit yields the tau-function for analytic curves encoding the integrable structure of the inverse potential problem and parametric conformal maps. A similar fermionic realization of partition functions for grand canonical ensembles of 2D Coulomb charges in the presence of an ideal conductor is also suggested. Their representation as Fredholm determinants is given and their relation to integrable hierarchies, growth problems and conformal maps is discussed. © 2010 Birkhäuser / Springer Basel AG. Source

Aliev M.A.,Institute of Biochemical Physics
Molecular Physics | Year: 2016

The isotropic-to-nematic phase transition in a melt of semi-flexible homopolymers with length polydispersity have been considered within the Landau–de Gennes approach. The number of monomer units in chain is assumed to be a random variable distributed by the Schulz–Zimm distribution; the stiffness of macromolecules has been taken into account within discrete worm-like chain model. It was found that increase of polydispersity yields the increase of the temperature of the isotropic–nematic transition. © 2016 Taylor & Francis Source

Tsvetkov N.A.,Korea Advanced Institute of Science and Technology | Larina L.L.,Korea Advanced Institute of Science and Technology | Shevaleevskiy O.,Institute of Biochemical Physics | Al-Ammar E.A.,King Saud University | Ahn B.T.,Korea Advanced Institute of Science and Technology
Progress in Photovoltaics: Research and Applications | Year: 2012

A barrier layer of undoped TiO 2 was deposited on the Nb-doped TiO 2 electrode to suppress the recombination at the Nb-doped TiO 2/dye-electrolyte interface for highly efficient dye-sensitized solar cells (DSCs). The Nb content in TiO 2 was varied in a range of 0.7-3.5 mol% to modify the TiO 2 energy-band structure. Nb-doped TiO 2/dye interfaces were characterized by a combination of ultraviolet photoemission spectroscopy and optical absorption spectroscopy measurements, allowing the determination of the conduction band minimum (CBM) of the TiO 2 electrode and the lowest unoccupied molecular orbital of the N719 dye. The lowering of TiO 2 CBM by Nb doping induced the increase in short-circuit current of DSCs. However, open-circuit voltage and fill factor are decreased, and this result was ascribed to the enhanced recombination at the Nb-doped TiO 2/dye-electrolyte interface. The effect of doping on charge transport in DSCs was analyzed using electrochemical impedance spectroscopy. We have shown that by introducing of TiO 2 barrier layer, the Nb doping content, which results in DSC highest efficiency, can be increased because of the suppression of the dopant-induced recombination. The energy conversion efficiency of the solar cells increased from 7.8% to 9.0% when undoped TiO 2 electrode is replaced with electrode doped with 2.7 mol% of Nb because of the improvement of the electron injection and collection efficiencies. The correlation between the electronic structure of the TiO 2 electrode, charge transfer characteristics, and photovoltaic parameters of DSCs is discussed. Copyright © 2012 John Wiley & Sons, Ltd. Source

Aliev M.A.,Institute of Biochemical Physics | Kuzminyh N.Yu.,Institute of Biochemical Physics | Ugolkova E.A.,RAS Institute of Chemistry
Physica A: Statistical Mechanics and its Applications | Year: 2013

The stability limits of the homogeneous state of melts of rod-coil RC, RC2, and CRC polydisperse block copolymers have been investigated in the framework of the weak segregation theory. It was assumed that the number of units in either the rod-like R or the flexible C block is a random variable distributed by the Schulz-Zimm distribution. Inspection of the spinodal curves shows that the copolymer melts with polydisperse rigid blocks are less stable with respect to formation of the nematic state than melts with the monodisperse ones. If flexible C blocks are polydisperse the homogeneous state of a rod-coil melt is less stable against microphase separation than the homogeneous state of monodisperse melt of the same architecture. © 2013 Elsevier B.V. All rights reserved. Source

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