Vol 486, No 2 (2019)
- Year: 2019
- Articles: 26
- URL: https://journals.eco-vector.com/0869-5652/issue/view/767
- DOI: https://doi.org/10.31857/S0869-56524862
Mathematics
About calculation with the high accuracy of eigenvalues of the operator Laplace in the ellipse (with the regional condition of Neumann)
Abstract
The method of the computing experiment investigates the task about fluctuations of the elliptic membrane with the regional condition of Neumann. It is shown that on the grid 40×61 it is possible to define up to 50 eigenvalues with several right significant figures for eccentricity e = 0.99999.
The reduction of the degree of integrals of hamiltonian systems with the help of billiards
Abstract
In the theory of integrable Hamiltonian systems with two degrees of freedom there are widely known integrable systems whose integrals have a high degree, namely 3 and 4: the Kovalevskaya system and its generalizations - the Kovalevskaya - Yahya system and the Kovalevskaya system on the Lie algebra so(4), Goryachev-Chaplygin-Sretensky, Sokolov and Dullin-Matveyev. The article shows that using integrable billiards bounded by arcs of confocal quadrics decreases the degree of integrals 3 and 4 of these systems fo some isoenergy 3-surfaces. Moreover, the integrals of degree 3 and 4 reduce to the same canonical quadratic integral on billiards.
Solvability of a problem for the equations of dynamics of one-temperature mixtures of heat-conducting viscous compressible fluids
Abstract
A system of partial differential equations governing the three-dimensional unsteady flow of a homogeneous two-component mixture of heat-conducting viscous compressible fluids (gases) is considered within the multivelocity approach. The model is complete in the sense that it retains all terms in the equations, which are a natural generalization of the Navier-Stokes-Fourier model for the motion of a single-component medium. The existence of weak solutions to the initial-boundary value problem describing the flow in a bounded domain is proved globally in time and the input data.
Physics
Synthesis and gas transport parameters of membranes modified by starshaped nanocrystalline palladium
Abstract
Methods have been developed to modify the surface of Pd-23%Ag alloy films in order to increase the rate of hydrogen transfer with appearance of palladium coatings of the “nanostar” and “nanopore” types. The gas transport parameters of the membranes which surface is activated using the developed methods were investigated. The modification of surface of Pd-Ag films synthesized by star-like palladium nanocrystallites allows achieving a hydrogen flux density of up to 0.75 mmol / (s × m2) - that is 1.7 times more than in case of modification modified by “nanopore” type coating of sufficiently thin palladium membranes (< 10 µm) under low temperature (<100 °C) and pressure (<0.6 MPa).
Estimation of the critical vitrification rate of pure metals using molecular dynamics simulation
Abstract
A molecular dynamics simulation method was applied for estimation of critical cooling rates (vc) that required for amorphization of pure metals: Mg, Al, Ti, Fe, Co, Ni, Cu, Zr, Mo, Pd, Ag, Ta, W, Pt, Au, and Pb. The range of values vc was found to be from 7.9 × 1011 K/s for Al to 3.8 × 1013 K/s for Zr. The atomic structure obtained at different cooling rates is described. A dependence of the specific volume on temperature was investigated both during the amorphization and crystallization processes. The modelling shows, which metals have the highest temperature range of long-term stability of the amorphous phase (Fe, Mo, Ta, W). Estimates were given for the maximum radius of a melt drop that can be cooled at a rate of vc. The obtained simulation results were compared with available experimental data.
Carbon nanotubes in arrays: competition of van der Waals and elastic forces
Abstract
The van der Waals interaction between carbon nanotubes leads to forming the agglomerates. If the nanotubes are the same diameters and legths they are associated into regular structure like a crystal. However, the van der Waals forces also result to some deformation of the nanotubes. This work presents the analysis of the influence of the nanotubes’ diameters and the symmetry of their arrangement on the nanotube deformation and intertube distances.
Energy science
Pulsed MHD generator of a new generation
Abstract
The results of calculation and theoretical investigation for the creation of a powerful (≈600 MW) pulsed MHD generator on the combustion products from solid (powder) plasma-forming fuel “Start-2” of a new generation are presented. The scheme, methods, results of calculations, and optimization of characteristics of the pulsed MHD generator with the self-excited resistive “iron-free” magnetic system are described. The local, integral, and specific energy and mass-dimensional characteristics are determined. The obtained characteristics are 1.5-2 times higher than those of the first generation MHD generator.
Chemistry
Cyclotribromoveratrylene in synthesis of porphyrin-containing polyphenols
Abstract
In this work we described a method of synthesis of porphyrin-containing polyphenols. These compounds were chemically combined with the molecular platform which based on cyclotriveratrylene core. The targeted ring system was synthesized through a palladium-catalyzed Suzuki-Miyaura coupling, with cyclotribromoveratrylene and 4-(4′,4′,5′,5′-tetramethyl-1′,3′,2′-dioxaborolan-2′-yl)-N,N-diporphyrinaniline as a key intermediates. The subsequent chemical transformations of a mentioned system were made for formation of targeted ring compound with free phenolic groups. These functional moieties were partially protected with acid-labile groups. Additionally, the using of porphyrin-containing polyphenols for chemically amplified positive photoresists could produce topological structures with 16 nm resolution on exposure by 13,5 nm wavelength of light.
One-step and selective approach to silicon-containing exo-norbornenes
Abstract
One-step and selective approach to the synthesis of Si-containing exo-norbornenes has been developed based on hydrosilylation reaction of norbornadiene-2,5 with unactivated silanes using Pd-complexes in the presence of bulky ligands. This approach leads to only exo-isomers of norbornene derivatives. The absence of alkylation step by organometallic compounds or photochemical isomerization makes the suggested approach promising for the synthesis of new polymeric materials with desired properties.
Physical chemistry
High-temperature heat capacity ErInGe2O7 and TbInGe2O7 in the range 350-1000 K
Abstract
SmFeGe2O7 germanate was obtained by solid-state reactions from stoichiometric mixtures of starting oxides with multistage firing within 1273-1473 K. The effect of temperature on the heat capacity of the compound was studied using differential scanning calorimetry. Based on the dependence Cp = f(T), its thermodynamic properties are calculated.
Geology
Design features of the Franz Josef Land volcanic provinces (Arctic Ocean): estimation of lava direction by anisotropy of magnetic susceptibility
Abstract
The paper presents the first results of studying the anisotropy of magnetic susceptibility in the basalts from Hooker Island, associated with the direction of the melt movement, the location of the eruption centers and the morphology of magmatic bodies. The established features of the primary magnetic fabrics correspond to the trap mechanism of formation of the volcanic province of the Franz Josef Land Archipelago and are a reflection of the simultaneous action of numerous small eruption centers. Previously obtained conclusions about the long, during the Early Jurassic - Early Cretaceous, multi-stage history of magmatism are not confirmed.
Correlation of magmatic and tectonic events in the evolution of the West Chukotka ophiolites
Abstract
The article is an overview of the magmatic and geodynamic processes that formed Aluchin and Gromadnen-Vurguvem ophiolites in the territory of Western Chukotka. The ophiolites formed into a convergent system between the Siberian continent and the Proto-Arctic Ocean. In the tectonic evolution of this system, important milestones have been identified: the Early Carboniferous, the Later Triassic and the Late Jurassic.
On the relationship of geodynamics, heat flow, deep structure and petroleum and gas potential of Yamal
Abstract
Hydrocarbon deposits concentration per unit square in Yamal is more than 100 times greater than the world average. Hydrocarbon deposits are generally located in regions with high modern geodynamic activity. The mantle structure in Yamal area has abnormal features according to seismic tomography. The southern part of Kara sea, Yamal and the western part of Gydan peninsula are situated in a big positive heat flow density anomaly with the epicenter near to Rusanovskoe deposit. Almost all deposits of hydrocarbones in Yamal are situated on the flanks of the West-Siberian rift system and simultaneously in gradient zones of heat flow density.
Reconstruction holocene environmental changes in North-Western Pacific in relation to paleorecord from Shikotan Island
Abstract
Results of a paleolimnological investigated of a well-dated lake sediment section from Shikotan Island (Southern Kurils) showed that from ca 8.0 to 5.8 cal ka BP warm and humid period corresponding to middle Holocene optimum took place. Cooling thereafter corresponds to Neoglacial. A reconstructed from ca 0.9 to ca 0.58 cal ka BP warm period can be correlated to a Medieval Warm Period. Cooling after 0.58 cal ka BP can be correlated with the LIA. Marine regression stages were identified at ca 6.2-5.9, 5.5-5.1 and 1.07-0.36 cal ka BP. The general chronology of major climatic events of Holocene in the island is in accordance with the climate records from the North Pacific region. Revealed spatial differences in timing and magnitude of the Late Holocene climatic episodes (LIA, MWP) within region needs further investigations.
Epigenetic graphitization in the basement of the Siberian craton - evidence of the migration of hydrocarbon-enriched fluids in the paleoproterozoic
Abstract
For the first time, diagnostics and structural studies of the сarbonaceous material (СM) of quartz-muscovite dinamoschists from schistase zones in biotite migmatites, pegmatites and diabases of the southern part of the Baikal ledge of the Siberian craton were performed. The сarbonaceous material is represented by clearly and microcrystalline graphite with residual hydrocarbon radicals. Native Ni, Sn, zincous Cu, intermetallic compounds of Fe-Ni composition, copper sulfides, rutile, monazite, and zircon were found in intergrowths with СM. The carbon isotopic composition is from -29.19 to -31.58‰, with the exception of CM from schistated diabase with δ13C = -24.93 ‰. The 40Ar/39Ar-dating of muscovite gave an age of 1947 ± 7.8 Ma, indicating a relationship between dynamometamorphism and the accretion of the Akitkan folded system with ancient craton complexes. It is concluded that the deposition of native carbon and metals is caused by the migration of essentially hydrocarbon fluid in the upper crustal formations.
Geochemistry
The nature of philogopite-ilmenite and ilmenite paragenesises in deep-seated xenoliths from Udachnaya kimberlite pipe
Abstract
The article describes the petrography and mineralogy of xenoliths ilmenite-phlogopite containing deformed and granular peridotites from the Udachnaya-Eastern pipe. The age of pholopite porphyroclast from the studied deformed xenoliths matches with age of phlogopite megacryst and itself hosted kimberlites from Udachnaya pipe indicating the following processes closed in time: 1) crystallization of the low-Cr megacryst association; 2) deformation of rocks on the mantle lithosphere - asthenosphere border during the kimberlite-forming cycle; 3) formation of protokimberlite melts.
Biogenic dissolution of quartz in laterite bauxites (by results of electron-microscopic study)
Abstract
For the first time carried out a systematic study under an electron microscope forms of a complete weathering of quartz in lateritic bauxites on khondalite and alluvial deposits of India. Demonstrated the appearance of dissolving individuals composing the quartz crystals, and their permanent connection with the abundant biomineral films, turned into a druses crystals of gibbsite - Al(OH)3. The solubility of quartz is due to its unique piezoelectric properties, abnormal expansion in inversion, the characteristics of the climate and the intense impact of the biochemical factor (organic residues, bacteria, biofilms, etc.)
Geochemical features of diamond-bearing suevites of the Kara astrobleme (Pay-Khoy)
Abstract
Results of geochemical studies of suevites of the Kara astrobleme (Pay-Khoy) produced by a new approach based on square microprobe analysis of suevite matrix and consolidated impact melts with multivariate statistics have been described for the first time. At list three suevite varieties have been divided which are essentially differ by geomorphological, mineralogical, petrological and geochemical criteria. The protoliths of the initial rocks of the target for the suevite varieties have been supposed on the basis of a complex analysis.
Geophysics
Okhotsk deep earthquake 24.05.2013: nature of coseismal earth’s oscillations and estimation of P-wave amplitudes at teleseismic distances
Abstract
The results of coseismic GPS observations in the epicentral area of 2013 Sea-of- Okhotsk earthquake are presented and specific features of seismic waves amplitudes variations with distance are detected basing on the records of Russian and international seismic stations. Global propagation of P-waves for the Sea-of-Okhotsk and Bolivian (09.06.1994) earthquakes was studied and their amplitudes on teleseismic distances were estimated.
Oceanology
Оn the role of eddies in the global ocean meridional heat transport
Abstract
By means of an eddy-resolving model, calculation of the eddy meridional heat transport (EMHT) in the World Ocean has been performed. Its distribution is associated with intense currents and forms several characteristic types of structures. Comparison with results of other models shows that for the correct reproduction of EMHT, an explicit description of the eddy dynamics is preferable.
Biochemistry, biophysics, molecular biology
Studying interactions between the Mod(mdg4)-67.2 protein and other isoforms of the Mod(mdg4) in the embryonic cells of Drosophila melanogaster
Abstract
It was found that in the embryonic cells of D. melanogaster, the isoforms of the Mod(mdg4) protein is able to interact with each other through the BTB domains. However, this non-specific interaction is destroyed when protein complexes recruiting to chromatin sites.
Thapsigargin, inhibitor of sarco-endoplasmic Ca2+-ATPase, effectively suppresses the expression of S100A4 in human breast cancer cell line
Abstract
Thapsigargin, the SERCA ATPase inhibitor, effectively suppresses the expression of metastasis marker S100A4 in breast cancer cells MDA-MB231. It has been demonstrated that transcription of the S100A4 gene is controlled by Ca2+-signaling pathways. It has been shown that synthesis of S100A4 mRNA and protein in the MDA-MB231 cell line is effectively inhibited by thapsigargin at a concentration of 0.4-4 µM, while preserving cell survival. We assume that a change in gene transcription in response to the disruption of Ca2+ homeostasis plays a direct role in the remodeling of Ca2+-signaling pathways.
Bicycronic construct for optogenetic prosthesis of ganglion cell receptive field of degenerated retina
Abstract
For the purpose of optogenetic prosthetics of the receptive field of the retinal ganglion cell, we have created a bicistronic genetic construct that carries genes of excitatory (channelorhodopsin2) and inhibitory (anionic channelorhodopsin) rhodopsins. A distinctive feature of this construct is the combination of two genes into one construct with the mutant IRES inserted between them, which ensures precise ratio of the expression levels of the first and second gene in each transfected cell. It was found that the illumination of the central part of transfected neuron with light with a wavelength of 470 nm causes the generation of action potentials in the cell. At the same time, light stimulation of the periphery of the neuron causes cessation of the generation of action potentials. Thus, we were able to simulate the ON-OFF interaction of the receptive field of the retinal ganglion cell using optogenetic methods. Theoretically, this construction can be used for optogenetic prosthetics of degenerative retina in case of its delivery to ganglion cells using lentiviral vectors.
Study оf dCTCF insulator activity in Drosophila melanogaster model systems
Abstract
Using Drosophila transgenic model systems, we have shown that the four binding sites for the architectural protein dCTCF themselves have no insulator activity. They cannot block enhancers and protect from Polycomb-dependent repression. The results suggest that in the known Drosophila insulators, the dCTCF protein functions in cooperation with other architectural proteins.