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11.
12.
V. A. Ketsko E. N. Beresnev M. A. Kop’eva L. V. Elesina A. I. Baranchikov A. I. Stognii A. V. Trukhanov N. T. Kuznetsov 《Russian Journal of Inorganic Chemistry》2010,55(3):427-429
This work demonstrates the possibility of preparing solid solutions in the (MgGa2O4)
x
(MgFe2O4)1 − x
system by pyrohydrolytic and solid-phase methods. It is shown that the products obtained have different specific surface
areas depending on the ratio between metal nitrates and citric acid. The composition dependence of the unit cell parameter
deviates considerably from the Vegard’s rule. The compounds obtained are found to be stable up to 300°C, which makes them
candidate materials for electronics. 相似文献
13.
We consider the competitive facility location problem in which two competing sides (the Leader and the Follower) open in succession
their facilities, and each consumer chooses one of the open facilities basing on its own preferences. The problem amounts
to choosing the Leader’s facility locations so that to obtain maximal profit taking into account the subsequent facility location
by the Follower who also aims to obtain maximal profit. We state the problem as a two-level integer programming problem. A
method is proposed for calculating an upper bound for the maximal profit of the Leader. The corresponding algorithm amounts
to constructing the classical maximum facility location problem and finding an optimal solution to it. Simultaneously with
calculating an upper bound we construct an initial approximate solution to the competitive facility location problem. We propose
some local search algorithms for improving the initial approximate solutions. We include the results of some simulations with
the proposed algorithms, which enable us to estimate the precision of the resulting approximate solutions and give a comparative
estimate for the quality of the algorithms under consideration for constructing the approximate solutions to the problem. 相似文献
14.
We consider a mathematical model of decision making by a company attempting to win a market share. We assume that the company
releases its products to the market under the competitive conditions that another company is making similar products. Both
companies can vary the kinds of their products on the market as well as the prices in accordance with consumer preferences.
Each company aims to maximize its profit. A mathematical statement of the decision-making problem for the market players is
a bilevel mathematical programming problem that reduces to a competitive facility location problem. As regards the latter,
we propose a method for finding an upper bound for the optimal value of the objective function and an algorithm for constructing
an approximate solution. The algorithm amounts to local ascent search in a neighborhood of a particular form, which starts
with an initial approximate solution obtained simultaneously with an upper bound. We give a computational example of the problem
under study which demonstrates the output of the algorithm. 相似文献
15.
N. M. Shtykov M. I. Barnik L. A. Beresnev L. M. Blinov 《Molecular Crystals and Liquid Crystals》2013,570(1):379-390
The phase-matched generation of the optical second harmonic was investigated in the chiral smectic C* phase of a classical ferroelectric liquid crystal (DOBAMBC). The phase-matching was achieved either by incidence angle or by temperature tuning. The temperature behaviour of the second order nonlinear susceptibility was studied. 相似文献
16.
E. N. Beresnev M. N. Smirnova N. P. Simonenko S. V. Makaev M. A. Kop’eva O. B. Kuznetsova V. A. Ketsko 《Russian Journal of Inorganic Chemistry》2016,61(8):1026-1030
The thermal behavior of the gels that are formed in the synthesis of MgFe1.6Ga0.4О4 powders was studied by differential scanning calorimetry and thermogravimetry (DSC–TG). The combustion temperatures of the gels in flowing air and flowing argon were determined from experimental data and thermodynamic calculations. The calculations of combustion temperatures from the heat flow of reaction versus time are shown to be a reliable tool to determine the parameters of gel combustion. 相似文献
17.
M. N. Smirnova L. V. Goeva N. P. Simonenko E. N. Beresnev M. A. Kop’eva V. A. Ketsko 《Russian Journal of Inorganic Chemistry》2016,61(10):1301-1306
The gel formed in the synthesis of Mg(Fe0.8Ga0.2)2O4 powder from corresponding metal nitrates and glycine was studied by thermal and IR spectral analyses. Being a bidentate ligand, glycine was established to initiate the gel combustion reaction resulting in the oxide of the above composition. Based on the data on ΔH298° and Cp of the reagents and reaction products, the thermodynamic parameters of this process were calculated. 相似文献
18.
S. M. Beresnev O. F. Bobrenok B. L. Kuzin N. M. Bogdanovich A. A. Kurteeva D. A. Osinkin G. K. Vdovin D. I. Bronin 《Russian Journal of Electrochemistry》2012,48(10):969-975
Single fuel cells with bilayer supported cathodes are manufactured and tested. The cathodes consist of a high-porous La0.6Sr0.4MnO3 support with the thickness of approximately 1 mm and a functional composite layer with the thickness of 13?C15 ??m made of La0.75Sr0.2MnO3 and 8YSZ. Voltammetric and power characteristics of single fuel cells with a supported cathode, thin-film YSZ electrolyte, and platinum cathode are determined. The conclusion as to the significant contribution into the polarization overpotential losses on the cathode is made on the basis of the measurements of electric fuel cell characteristics. It decreases significantly as a result of the supported cathode modification by praseodymium oxide. At 850°C and voltage of 0.81 V, electric power density of a fuel cell was 1.65 W/cm2. 相似文献
19.
V. L. Beresnev E. N. Goncharov A. A. Mel’nikov 《Journal of Applied and Industrial Mathematics》2012,6(1):22-30
In the optimization problem for pseudo-Boolean functions we consider a local search algorithm with a generalized neighborhood.
This neighborhood is constructed for a locally optimal solution and includes nearby locally optimal solutions. We present
some results of simulations for pseudo-Boolean functions whose optimization is equivalent to the problems of facility location,
set covering, and competitive facility location. The goal of these experiments is to obtain a comparative estimate for the
locally optimal solutions found by the standard local search algorithm and the local search algorithm using a generalized
neighborhood. 相似文献
20.
D. A. Osinkin N. M. Bogdanovich S. M. Beresnev E. Yu. Pikalova D. I. Bronin Yu. P. Zaikov 《Russian Journal of Electrochemistry》2018,54(8):644-649
The anodic and cathodic polarization dependences for the oxygen electrode based on lanthanum-strontium manganite and the fuel Ni-cermet electrode are studied in the temperature range of 700–900°С in gas media that correspond to working conditions of a reversible fuel cell. The temporal behavior of these electrodes is studied in the course of periodic polarity changes of current with the density of 0.5 A/cm2. The electrode overvoltage is shown to be about 0.1 V in modes of power generation and water electrolysis at 900°С and the current density of 0.5 A/cm2. A single electrolyte supported tubular solid-oxide fuel cell was fabricated and tested in the fuel-cell and hydrogen-generation modes. It is found that at 900°С and overvoltage of 0.7 V, the cell generates the specific electric power of 0.4 W/cm2 when the 50% H2 + 50% H2O gas mixture is used as the fuel and air is used as the oxidizer. At the water electrolysis with the current density of 0.5 A/cm2, which under normal conditions corresponds to generation of about 0.2 and 0.1 L/h of hydrogen and oxygen, respectively, the consumed power is about 0.55 W/cm2. The efficiency of the conversion cycle electric power–hydrogen–electric power is 70–75%. 相似文献