Vol 487, No 2 (2019)

Mathematics
System of equations for boundary layer of rheologically complex media. The Crocco variables
Bulatova R.R., Samokhin V.N., Chechkin G.A.
Abstract

In the paper one studies the system of equations of the boundary layer of nonlinearly viscous fluid with the O. A. Ladyzhenskaya law. Previously, these equations were considered, the Mises transform allows to reduce the system of equations to a single quasilinear equation. In this work, we use the Crocco variables, which transform the system of equations of the boundary layer into a quasilinear degenerate parabolic equation. In contrast to the Mises variables, the Crocco transformation allows one to study both stationary and non-stationary equations; moreover, it makes it possible to obtain asymptotic estimates for the solution on the boundary of the domain.

Доклады Академии наук. 2019;487(2):119-125
views
On polynomial solvability of one quadratic Euclidean clustering problem on a line
Kel’manov A.V., Khandeev V.I.
Abstract

We consider the problem of partitioning a finite set of points in Euclidean space into clusters so as to minimize the sum over all clusters of the intracluster sums of the squared distances between clusters elements and their centers. The centers of some clusters are given as an input, while the other centers are defined as centroids (geometrical centers). It is known that the general case of the problem is strongly NP-hard. We show that there exists an exact polynomial algorithm for the one-dimensional case of the problem.

Доклады Академии наук. 2019;487(2):126-129
views
Informatics
Depth map reconstruction based on features formed by descriptor of stereo color pairs
Kravchenko V.F., Ponomaryov V.I., Pustovoit V.I., Rosas-Miranda D.
Abstract

Novel local image descriptor that is tested in the computer vision problem is proposed. The designed descriptor is based on visual primitives and relations between them, namely, coplanarity, cocolority, distance and angle. The designed feature descriptor covers both geometric and appearance information. Proposed descriptor has demonstrated its ability to compute depth maps from image pairs where the performance evaluation via criterion Bad Matching Pixels has shown it superior quality in comparison with other descriptors from state-of-the-art methods.

Доклады Академии наук. 2019;487(2):130-134
views
Physics
Caustics of vortex optical beams
Soifer V.A., Kharitonov S.I., Khonina S.N., Volotovsky S.G.
Abstract

The work is devoted to the study of caustics of vortex optical beams. An asymptotic method for calculating the caustic surfaces of vortex beams was developed. The formulation of the inverse problem of the formation of axial caustics of the required type is considered. It is shown that the presence of the vortex component leads to the formation of an axisymmetric caustic surface, the characteristic diameter of which increases with increasing topological charge.

Доклады Академии наук. 2019;487(2):135-139
views
Mechanics
Extreme properties of oscillations of an elliptical float
Akulenko L.D., Baydulov V.G.
Abstract

Extreme in amplitude and frequency properties of oscillations of a thin elongated flat body of elliptical form in the vicinity of the interface of stably stratified ideal fluids are studied. Numerical and analytical procedures have been developed for solving a self-consistent boundary value problem on an asymptotically large time range. The time-dependences of the amplitude decay and frequency of oscillations are obtained. The comparison with similar characteristics, found early by the authors for floats of other forms, is carried out, and significant quantitative and qualitative differences were established.

Доклады Академии наук. 2019;487(2):140-143
views
Double spiral vortex as a possible reason of wall-free non-stationary air vortices generation
Varaksin A.Y., Mochalov A.A.
Abstract

In this work, for the first time, a double spiral non-stationary structure of interacting helical filaments, preceding the generation of a non-stationary air vortex, was discovered and described.

Доклады Академии наук. 2019;487(2):144-146
views
Influence of pressure gradient and capillary forces on ice formation in soil
Tsypkin G.G.
Abstract

Ice formation in unsaturated soil is investigated, in the presence of pressure gradient and capillary forces. It is shown that in linear approximation the problem of determining of the amount of ice formed reduces to solving a non-uniform diffusion equation for water saturation. Similarity solution of the problem in one-dimensional case is obtained. It is found that the pressure drop at the cooling wall causes flow of water towards the crystallization front and leads to an increase in the amount of ice that forms.

Доклады Академии наук. 2019;487(2):147-150
views
Chemistry
Reduction of acridine and 9-chloroacridine by red phosphorus in the KOH/DMSO system
Kuimov V.A., Gusarova N.K., Malysheva S.F., Kon’kova T.V., Trofimov B.A.
Abstract

Acridine reacts with red phosphorus in KOH/DMSO(H2O) system upon heating (100 ºC, 3 h) to regioselectively give and 9,10-dihydroacridine in almost quantitative yields. Under similar conditions, the reaction of 9-chloroacridine with the system Pred/KOH/DMSO(H2O) affords 9,10-dihydroacridine and acridone in 51 and 40% yields respectively.

Доклады Академии наук. 2019;487(2):151-153
views
New method for synthesis of binary borides with desired properties
Malinina E.A., Goeva L.V., Buzanov G.A., Avdeeva V.V., Efimov N.N., Kuznetsov N.T.
Abstract

In this work, complexes [Co(solv)n][B10H10] (I: solv = H2O, n = 6; II: solv = N2H4, n = e synthesis of binary borides is shown. The purity and homogeneity of the precursors and the products of their thermal reduction (in an inert atmosphere at 650 and 900 °C) has been established by the methods of elemental analysis, X-ray powder diffraction, and IR spectroscopy; magnetochemical studies of precursors and their annealing products have been carried out. According to the data obtained, the reduction products are structured oxide-boride and nitride-boride phases, respectively. Magnetochemical study of the phases showed a significant difference in their magnetic behavior: the oxide-boride phase is characterized by a significant ferromagnetic contribution to the total magnetization of the sample, and the nitride-boride phase is diamagnetic.

Доклады Академии наук. 2019;487(2):154-158
views
The formation of nanowhiskers in syntactic foam containing tungsten under nanosecond flow of relativistic electrons
Milekhin Y.M., Sadovnichii D.N., Sheremetyev K.Y., Kalinin Y.G., Kazakov E.D., Markov M.B.
Abstract

The results of experimental studies of the nanowhiskers formation under the influence of relativistic electron beams of nanosecond duration on syntactic foam containing tungsten are presented. We demonstrated effects which observed after a single impact of relativistic electron beams with a flux density of 230-240 J/cm2 and a total pulse duration of 150 ns. The spheres with diameter of more than 40 µm are destroyed in irradiated syntactic foam. Filamental structure is formed on the surface of such spheres. Its length is up to 10 µm and a diameter of about 100 nm. The complex kinetics substance expansion from the irradiated surface was found out. The speeds of gas-plasma formations expansion reached ~ 13 km/s. It was found that nanowhiskers are not formed near the emission “crater” from syntactic foam, where the duration of the mechanical pressure pulse is minimal and close to the duration of the relativistic electron beam impact.

Доклады Академии наук. 2019;487(2):159-163
views
Chemical Technology
Production of methane hydrates in dispersed frozen aqueous solutions of polyvinyl alcohol
Mel’nikov V.P., Podenko L.S., Drachuk A.O., Molokitina N.S.
Abstract

The results of studying of the methane hydrate formation kinetics were presented. Dispersed frozen polyvinyl alcohol (PVA) solutions were used to form methane hydrate. The experiments were carried out in an unstirred reactor at the temperature near the ice melting point. Based on the obtained results it was found out that the water to hydrate transition time highly reduced (by several times) in the dispersed frozen PVA solutions than that in dispersed ice. It was established that the hydrate formation rate and the water to hydrate transition degree might be higher in the dispersed frozen PVA solutions than in aqueous solutions of surface-active agents and “dry water”.

Доклады Академии наук. 2019;487(2):164-168
views
Physical chemistry
Strong dependence of contact angle on pressure
Rusanov A.I., Esipova N.E., Sobolev V.D.
Abstract

Although the usual pressures typically only slightly affect the properties of condensed phases and their surface layers, in physical chemistry of surfaces, it was found a quantity, the contact angle on the three-phase contact line, that is very sensitive to pressure. In experiments with an air bubble in water stuck to a solid surface, an increase in hydrostatic pressure of less than doubled gave an increase in the contact angle of more than 10º if the angle itself was sufficient but less than 90º. Сhanging the orientation of the liquid - gas surface. If the angle (no matter sharp or obtuse) is close to 90º, the mobility of the three-phase contact line arises as an alternative way to achieve equilibrium. To explain these phenomena, a thermodynamic theory is formulated. It is shown that with a fixed line of three-phase contact, an increase in pressure in a liquid always causes an increase in the contact angle. At the same time, an increase in the hydrostatic pressure of water by two times is equivalent to an increase in the partial pressure of water vapor inside the bubble by a factor of seven.

Доклады Академии наук. 2019;487(2):169-173
views
Geology
The first determination of the andesite-dacite complex isotope age of the Middle Urals Еastern zone
Koroteev V.A., Chervyakovskiy V.S., Zaitseva M.V., Volchek E.N., Necheukhin V.M.
Abstract

In the paper are given the results of the first performed U-Pb dating of zircons from dacites and volcanic paleostructure of the Eastern zone andesite-dacite complex of the Urals orogen middle-uralian part, consisting of retro-overthrusted and cover-folded structural subzones. Volcanogenic complex, including vent and nearvent facies, occurs among flyschoid and carbonate deposits with the Middle Devonian fauna in cover-folded structural subzone forming an extreme eastern orogen limitation. Zircon grain age made up 389±5,6 Ma that also correlates with Middle Devonian. Consequently the formation of sedimentary and volcanogenic complexes occurred in a close age interval, but judging by their composition and structure, in different environmental conditions. Sedimentary formations accumulated in shallow basins, and the volcanic ones have been formed, apparently, under sub-areal conditions surrounded by the shallow sea basin. It is assumed that the manifestation of andesite-dacite volcanism, most probably, testifies to the spatial and age displacement of geodynamical and facies conditions to the eastern periphery of the orogen.

Доклады Академии наук. 2019;487(2):174-178
views
First data on the composition of the Atlantis Rise rocks (Central Atlantic)
Peyve A.A.
Abstract

Paper provides original data on the composition of the volcanic rocks of Atlantis Rise in the Central Atlantic. In relation to incompatible elements, volcanics of the Rise were formed at low degrees of partial melting within the garnet depth facies. According to Pb and Nd isotopic ratios, their composition cannot be unconditionally attributed to any of the nearby magmatic provinces (Madeira, Canary or Cape Verde). They are distinguished by the high radiogenity of Pb isotopes, pointing to a significant addition of the HIMU component. There is no significant addition of the EM 1 component. We can assume that the volcanics of the of the Atlantic Rise were formed from an independent mantle source.

Доклады Академии наук. 2019;487(2):179-184
views
First finding of the fossil leaf flora in cenozoic deposits on Sardakh-Sisse Island (Lena River delta)
Khazin L.B., Kuzmina O.B., Khazina I.V., Lashchinskiy N.N., Kartoziia A.A., Kashirtsev V.A.
Abstract

During the field works in the summer of 2018, in the Lena River delta on the Sardakh-Sisse Island, prints of leaf flora belonging to species of broad and small-leaved deciduous trees were found. The prints found by us are confined to the layer of ferruginous sandstones at the base of the section. The following taxa established: Platanus sp., Alnus sp., Fagus sp., Salix sp. In addition, a fossilized fruit belonging to Magnolia sp. The findings allow to conclude that there are mixed forests in the early-middle Miocene in this region, consisting of coniferous, small- and broad-leaved deciduous species of trees and shrubs.

Доклады Академии наук. 2019;487(2):185-188
views
Geochemistry
Estimation of the accumulation of impurity K and Na ions in the CaSiO3 and MgSiO3 crystal structures at pressures 18-25 GPa
Eremin N.N., Bobrov A.V., Marchenko E.I.
Abstract

Based on the data of atomistic modeling, various schemes of the isomorphic occurrence of K+ and Na+ ions in the crystal structures of CaSiO3 and MgSiO3 in the pressure range 18-25 GPa and temperatures of 1873-2223 K were analyzed. Under these PT parameters, the content of K+ and Na+ in structures under investigation was estimated. The semiempirical simulation data are in good agreement with the results of experiments with perovskite structure phases.

Доклады Академии наук. 2019;487(2):189-191
views
Reconstruction of environmental changes by the diatom complexes of lake sediments in Western Siberia
Moiseenko T.I., Razumovsky L.V.
Abstract

Evaluation of Western Siberia lake sediments information content to reconstruct the latest geo-environmental and climatic changes. The possibility of reliable registration of negative changes in physical and chemical parameters of lake waters on the basis of classical and innovative methods of diatom analysis.

Доклады Академии наук. 2019;487(2):192-197
views
High temperature Al-Ca сondensate in lunar regolith
Моkhov А.V., Gornostaevа Т.А., Kartashov P.M., Rybchuk А.P., Bogatikov О.А.
Abstract

For the first time in natural conditions in the samples of lunar regolith from the Mare Crisium (“Luna-24” station) a high-temperature condensate was found in the form of binary glass balls of dimensions in the order of 200-400 nm, consisting of an oxide Al-Ca core covered with an uniform film of high-silicon glass, containing iron nano-inclusions. Previously, high-temperature condensate was only theoretically predicted on the basis of laser evaporation experiments.

Доклады Академии наук. 2019;487(2):198-202
views
Evolution of high magnesian melts during processes of crystallization of rocks from the ultramafic massifs of the Siberian platform
Simonov V.A., Vasiliev Y.R., Kotlyarov A.V., Prihodko V.S.
Abstract

We determined the chemical composition of high-mg picrite-basaltic melts that formed the ultramafic massifs of the Siberian platform in the study of primary melt inclusions in accessory chrome spinel from dunites. We determined the temperature of crystallization of olivine from dunites of the Gulinsky (1520-1420 °C), Kondersky (1545-1430 °C), Inaglinsky (1530-1430 °C), Chadsky (1460-1420 °C) intrusives and chrome spinels of these complexes: Gulinsky (1410-1370 °C), Kondersky (1420-1380 °C), Inaglinsky (up to 1430 °C), Chadsky (1430-1330 °C), using a computer simulation (program PETROLOG and PLUTON) on the basis of data on the composition of the inclusions. Тhe computational modeling allowed us to establish that there were two types of high-magnesium melt evolution on the Siberian platform. The first type is characteristic of the Gulinsky pluton, where there is the following sequence of formation: the dunites → pyroxenites → alkaline rocks. The second type is represented Kondersky massif, where the sequence is different: dunites → kosvites → pyroxenites and olivine-diopside rocks.

Доклады Академии наук. 2019;487(2):203-207
views
Geography
The high-resolution oxygen isotope diagram of late Pleistocene ice wedges of Seyaha yedoma, Eastern Yamal Peninsula
Vasil’chuk Y.K., Budantseva N.A., Vasil’chuk A.C.
Abstract

The main objective of this work is to study the oxygen isotope composition of late Pleistocene syngenetic ice wedges and to obtain a high-resolution isotope diagram from a carefully sampled outcrop of Seyaha yedoma within of the third lagoon-marine terrace near the Seyaha (Zelyonaya - Green) river mouth, on the bank of the Ob Bay. According to 3 new radiocarbon ages: from 25.2 to 23.3 kyr BP from +2 to +5 m a.s.l., as well as dates: 17.3 kyr from +18.8 m a.s.l. and 11.6 kyr BP from +21.2 m a.s.l., the age of the ice wedge is from 23 to 15 to 18 kyr BP approximately. Values of δ18O in the upper fragment of the ice wedge vary from -25.75 to -3.15‰. Horizontal variations of δ18O values at a height of +15.2 m amounted to 1.49‰, from -23.41 to -24.9‰. The ice of the lower fragment of the ice wedge, at +6 m a.s.l., is characterized by a wider range of δ18O values than in the upper fragment. The horizontal values of δ18O range from -23.41 to -26.63‰.  The obtained oxygen isotope diagram in the upper fragment of the ice wedge has resolution of 80-100 years. According to palaeoreconstruction the average January temperature 23-15 (18) kyr BP ranged from -35 to -39 °C.

Доклады Академии наук. 2019;487(2):208-211
views
Oceanology
Applying of deuterium excess for identification of fresh water sources in the bays of Novaya Zemlya archipelago
Kossova S.A., Dubinina E.O., Miroshnikov A.Y., Flint M.V.
Abstract

An isotopic-geochemical study was carried out for the waters of Tsivolki and Sedov bays (southeastern coast of the Novaya Zemlya archipelago). Waters of these bays can be freshened by several potential sources, which are river runoff from the continent, atmospheric precipitation of the region, waters coming from the archipelago. The possibility to use deuterium excess for identification of freshwater components in the waters, which enter the studied bays, is shown. Calculations made on the material sampled in 2015 showed the presence of the Ob River estuary waters in the surface waters of the Sedov Bay. At the same period, the waters of the halocline of Tsivolki Bay show freshening by local sources - runoff from the Novaya Zemlya archipelago.

Доклады Академии наук. 2019;487(2):212-216
views
Biochemistry, biophysics, molecular biology
Changes in the quantitative and functional characteristics of bacterioplankton under the influence of aqueous unmodified fullerene dispersions С60
Mosharova I.V., Dallakyan G.A., Mikheev I.V., Il’inskii V.V., Akulova A.Y.
Abstract

The effect of aqueous unmodified fullerene C60 dispersions (AFD) at a concentration of 5 mg/l on the total number and metabolic activity of heterotrophic river bacteroplankton has been investigated. The stimulating effect of AFD on the number of bacterioplankton and on the activity of electron transport chains in its cells is shown. It is established that in the presence of AFD decreases the bactericidal activity of antibiotics. The stimulating effect of fullerene on the natural heterotrophic bacterioplankton, which we found out, casts doubt on the expediency of using AFD as a bacteriostatic agent.

Доклады Академии наук. 2019;487(2):217-220
views
New targets of Kunitz-type peptide from sea anemone Heteractis magnifica
Kvetkina A.N., Kaluzhskiy L.A., Leychenko E.V., Isaeva M.P., Ivanov A.S., Kozlovskaya E.P.
Abstract

The interaction of Kunitz-type peptide, HMIQ3c1, from sea anemone Heteractis magnifica with several serine proteases including inflammatory proteases was investigated using surface plasmon resonance approach. We showed that recombinant analog of HMIQ3c1 makes strong enough complexes with trypsin (KD = 1,07 × 10-9 М) and chymotrypsin (KD = 4,70 × 10-8 М). Analysis of thermodynamic parameters of HMIQ3c1/chymotrypsin revealed significant contribution of entropic factor in complex formation. The formation of specific complexes of HMIQ3c1 with neutrophil elastase (KD = 1,11 × 10-7 М) and kallikrein (KD = 2,81 × 10-8 М) indicates its anti-inflammatory activity and makes prospects to use the peptide as a potential therapeutic agent.

Доклады Академии наук. 2019;487(2):221-224
views

This website uses cookies

You consent to our cookies if you continue to use our website.

About Cookies