Vol 485, No 3 (2019)
- Year: 2019
- Articles: 27
- URL: https://journals.eco-vector.com/0869-5652/issue/view/762
- DOI: https://doi.org/10.31857/S0869-56524853
Full Issue
Mathematics
Homogenization of the boundary value problem for the poisson equation with rapidly oscillating nonlinear boundary conditions: space dimension n ≥ 3, critical case
Abstract
The homogenization of the Poisson equation in a bounded domain with rapidly oscillating boundary conditions specied on a part of the domain boundary is studied. A Neumann boundary condition alternates with an ε-periodically distributed nonlinear Robin condition involving the coefficient ε−β, where β ∈ R. The diameter of the boundary portions with a nonlinear Robin condition is of order O(εα), α > 1. A critical relation between the parameters α and β is considered
Degenerate boundary conditions on a geometric graph
Abstract
The boundary conditions of the Sturm-Liouville problem defined on a star-shaped geometric graph of three edges are studied. It is shown that if the lengths of the edges are different, then the Sturm-Liouville problem does not have degenerate boundary conditions. If the lengths of the edges and the potentials are the same, then the characteristic determinant of the Sturm-Liouville problem can not be equal to a constant different from zero. But the set of Sturm-Liouville problems for which the characteristic determinant is identically equal to zero is an infinite (continuum). In this way, in contrast to the Sturm-Liouville problem defined on an interval, the set of boundary-value problems on a star-shaped graph whose spectrum completely fills the entire plane is much richer. In the particular case when the minor A124 for matrix of coefficients is nonzero, it does not consist of two problems, as in the case of the Sturm-Liouville problem given on an interval, but of 18 classes, each containing two to four arbitrary constants.
Mathematical physics
Vlasov-Poisson-Poisson equations, critical mass and kordylewski clouds
Abstract
A derivation of the Vlasov-Poisson-Poisson equation is proposed for studying stationary solutions of a system of gravitating charged particles in vicinity of triangular libration points (Kordylevsky cloud). Stationary solutions are sought as functions of integrals, which leads to elliptic nonlinear equations for the potentials of the gravitational and electrostatic fields. This gives a critical mass: for bodies with large masses dominates gravitation forces, and for bodies with smaller masses - electrostatic forces.
Physics
Temperature measurements of optically cooled calcium atoms using differential two-photon spectroscopy
Abstract
A differential two-photon method of measuring the temperature of 40Ca atoms in a continuously operating magneto-optical trap is demonstrated. Coherent two-photon resonances at the 4s2 1S0-50 1S0 Rydberg transition have been investigated experimentally using resonance laser beams propagating at different angles. The temperature of the cloud of 40Ca atoms was measured depending on the frequency detuning of the cooling laser radiation.
Mechanics
Speedup of a Chaplygin top by means of rotors
Abstract
In this paper we consider the control of the motion of a dynamically asymmetric unbalanced ball (Chaplygin top) by means of two perpendicular rotors. We propose a mechanism for control by periodically changing the gyrostatic momentum of the system, which leads to an unbounded speedup. We then formulate a general hypothesis of the mechanism for speeding up spherical bodies on a plane by periodically changing the system parameters.
Control of the structure of flow around a rhomboid wing in supersonic flow
Abstract
Certain results of the numerical investigation of the possibility of controlling the structure of flow near a V-shaped wing with an opening angle greater than p under an asymmetric flow around by a supersonic stream under the regimes with shock waves attached to the leading edges or with a centered rarefaction wave on the lee console are presented.
On rolling friction
Abstract
The dependence of rolling friction on velocity for various contact conditions is discussed. The principal difference between rolling and other types of relative motion (sliding and spinning) is that the points of the body in contact with the support change over time. Due to deformations, there is a small contact area and, entering into contact, the body points have a normal velocity proportional to the diameter of this area. For describing the dependence of the friction coefficient on the angular velocity in the case of “pure” rolling, a linear dependence is proposed that admits a logical explanation and experimental verification. Under the combined motion, the rolling friction retains its properties, the sliding and spinning friction acquiring the properties of viscous friction.
Combustion of a plane hydrogen microjet at subsonic and supersonic speeds
Abstract
In this paper, we presented the results of experimental studies of the diffusion combustion of a plain hydrogen microjet flowing from a slit micronozzle at subsonic and supersonic speeds. For the first time, four scenarios of diffusion combustion of a plain hydrogen microjet including supersonic combustion in the presence of supersonic cells in both air and hydrogen are presented. The stabilization of the subsonic combustion of a hydrogen microjet was established to be due to the presence of a «bottleneck flame region» while the stabilization of the supersonic combustion of a microjet was found to be associated with the presence of supersonic cells. The observed hysteresis of diffusion combustion of a plain hydrogen microjet depends on both the method of igniting the microjet (near or far from the nozzle exit) and the direction of change in the rate of its outflow (growth or reduction).
Chemistry
Water soluble metal-polymeric complexes of gallium and triple co-polymer of N-vinylpyrrolidone with N-vinylformamide and N-vinylminodiacetic acid
Abstract
A terpolymer with a molecular weight of 45 kDa containing 7 mol.% of vinylamine units, 80 mol.% of vinylpyrrolidone, and 3 mol.% of vinyliminodiacetic acid units has been synthesized. Its complexation with Ga3+ ion has been studied by HPLC. The resulting metal–polymer complex has been characterized by exclusion chromatography and spectral (IR, 1H NMR) data. The complex has a monomolecular structure where the metal ion acts as an anchor fragment between vinyliminodiacetic acid units and is stable in the reaction of interligand exchange with histidine.
Chemical Technology
New 4,5-diaza-9,9'-spirobifluorene derivative – promising electron acceptor for nonfullerene polymer solar cells
Abstract
New 4,5-diaza-9,9'-spirobifluorene derivative 8 with two electron-accepting perylene diimide moieties has been prepared. The compound 8 was characterized by NMR spectroscopy, elemental analysis, UV-spectroscopy and cyclic voltammetry. Energies of HOMO/LUMO levels are of -5.81 eV/-3.89 eV; Egopt and Egech values are of 1.75 eV and 1.92 eV, respectively. Low-lying energy levels and strong absorption in the visible region of UV- spectrum indicate the potential use of the compound 8 as a new promising electron acceptor in nonfullerene polymer solar cells.
Physical chemistry
Unstable necking due to deformation softening of polybutylene succinate
Abstract
Self-oscillating neck propagation of amorphous polybutylene succinate was studied. The neck propagated by regular neck front jumps at the stretching speeds from 0.05 to 1000 mm/min. Self-oscillations at extremely low stretching speeds contradicts to the theory of this phenomenon. The instability of the neck propagation was explained by the deformation softening of the polymer.
Geology
40Ar/39Ar age of the gold-silver Burinda deposit and its relationship to magmatism (north-eastern part of the argun superterrane)
Abstract
It was established that the age of hydrothermal ore metasomatites of the Burinda gold-silver deposit, one of the most famous in eastern Asia, can be estimated in the interval 126-128 Ma. It is shown that the formation of this deposit is due to hydrothermal processes in the final stages of the formation of the Taldan volcanic complex.
New data on the volcanism of the Central Chukotka segment of Okhotsk-Chukotka volcanogenic belt
Abstract
The article presents new geochronological and geochemical data on the age and composition of the undifferentiated Cretaceous volcanics of the basin of the Palyavaam river Central Chukotka region. These data indicate the heterogeneity of the rocks of etchikun suites, which are divided into two groups. The andesites of the first group (actually etchikun suites ) are of early Cretaceous age and represent a magmatic phase preceding the formation of the Okhotsk-Chukotka volcanogenic belt (OCHVB). The andesites of the second group correlate well in age and composition to the volcanic rocks of OCHVB. They lie at the base section of Chaunskaya series of OCHVB and indicate gomodromos the evolution of volcanism in the Central-Chukchi sector OCHVB.
Main features of the structure, litological composition, and thickness of the quaternary deposits cover in the eastern Barents sea
Abstract
Analysis of the data of seismoacoustic investigation and geotechnical drilling in the western Barents Sea has shown the following. The Upper Weichselian glacial deposits cover spread regionally. It represents seismostratigraphic complex (SSK) SSK III, unconformity occurs on the Mezozoic deposits, partly – on the Lower Weichselian moraine (SSK V) and is overlain unconformity by the Late Glacial glaciomarine (SSK II) – Holocene marine (SSK I) sediments. SSK III consists of two seismofacies (SF). Predominant SSF III-C are formed by the ordinary moraine almost solely, and SF III-T – by the M-moraine. The presence of these moraines determine of SSK III thicknesses distribution nearly completely. The ordinary moraine thickness fluctuates from < 10 m to 10–25 m. The M-moraine forms huge in plan, positive accumulation bodies in which its thickness > 25 m and arrives at 50–75 m. The other grandiosity structure-morphological elements of the Upper Weichselian deposits cover are: end moraines (the giant form was discovered) and powerful subglacial cuts, which represents unique unburied analog of the known so-called tunnel valleys. Structure, composition, thicknesses particularities of SSK III deposits cover were conditioned by specific character of process of the Last Glaciation development in the region.
Geochemistry
Rare-metal granites from various zones of the early mesozoic magmatic areal (Mongolia): geochemical and petrogenetic features
Abstract
This study is aimed at comparative analysis of the chemical evolution, age, and petrogenetic features of the Li–F granites from various zones of the Early Mesozoic magmatic areal. The newly obtained geochemical data preclude the formation of rare-metal Li–F granites by processes of magmatic differentiation of a palingenic granitic magma, parental to the Baga–Khentei Pluton. The rare-metal granites of the peripheral zone of the Early Mesozoic magmatic areal, compared to their counterparts from the central part (the Baga–Khentei Pluton), are more enriched in some elements that accumulated intensively during fluid-magmatic differentiation (Li, Rb, Sn, Ta, and F), often forming a concentrated mineralization. This corroborates the potential of rifted fringes of batholiths in the context of the connection of rare-metal mineralization and magmatism. The geochemical specifics of the Khentei intrusion granite from the central part of the Early Mesozoic magmatic areal may imply a deeper source related to the mantle plume.
First data on yatulian (2.1 Ga) metamorphism in the Belomorian mobile belt
Abstract
The Sm-Nd isotope ages of apoamphibolite eclogites and eclogite-like garnet-clinopyroxene crystalline schists collected in the Chupa and Engozero segments of the Belomorian mobile belt are estimated. Eclogites and eclogite-like garnet-clinopyroxene rocks demonstrated nearly the same isotope age (2119±170 and 2191±39 Ma, respectively) on the same pair of minerals (garnet-clinopyroxene). The age obtained (about 2.1 Ga) is the oldest indicator of the onset of Paleoproterozoic metamorphism in the Belomorian mobile belt.
Formation parameters of high-pressure minerals in the Dhofar 717 AND 864 chondrite meteorites
Abstract
This paper presents the results of a Raman spectroscopic study of shock melt veins in L6 chondritic meteorites Dhofar 717 and 864, and conclusions about the PT-parameters recorded in these meteorites after the impact event. The primary minerals of the host chondrite include olivine, orthopyroxene, clinopyroxene, plagioclase, chromite, phosphates, troilite, and kamasite. Shock melt veins up to 1 cm thick contain fragments of the high- pressure minerals ringwoodite, wadsleyite, majorite, akimotoite, jadeite, lingunite, and tuite and quenched melt consisting of majorite, ringwoodite, troilite, and kamasite. The mineral associations of the Dhofar 717 and 864 chondrites indicate high peak PT-parameters of the impact in the region of stability of majorite (>20 GPa and >2500 K) and bridgmanite (>25 GPa and >2500 K). The presence of lingunite also directly indicates a peak pressure in the area of stability of the bridgmanite.
Effect of natural organic acids on mobilization of macro- and microelements from rocks
Abstract
Experimental study of leaching of the main cations (Na, K, Mg, and Ca), alkaline and alkaliearth microelements (Li, Rb, Cs, Be, Sr, and Ba), heavy metals (Mn, Fe, Co, Ni, Cu, Zn, Cd, Tl, and Pb), hydrolyzate elements (Y, RZ, Ti, Th, and U), and anionic elements (F, Si, P, and V) from rocks of different acidity with distilled water and a multicomponent solution of organic acids, having the distribution of dissociation constants corresponding to natural dissolved organic matter was carried out. It has been shown that carboxylic acids, which are part of the dissolved organic matter contained in surface waters, cause a sharp increase in the mobilization of both the main cations and trace elements from silicate rocks. The chemical properties of the elements are of secondary importance, as was shown by the general correlation between the parameter related to the mobility of the elements at the initial stage of the leaching and their content in the rocks.
238U/235U isotopic ratio as redox conditions marker in ediacarian paleobasin: section in Chaya river, Baikal-Patom highland, south of middle Siberia
Abstract
This article is devoted to a study of variations in the U isotopic composition (238U/235U) in the section of clas- tic-carbonate Ediacaran sediments exposed along the Chaya River in the southern part of Central Siberia (Russia). Measurements of 238U/235U in the rocks were performed using a high-precision (±0.07%o, 2SD) MC-ICP- MS with a 233U-236U double isotope spike. The total variation range of S238U in the studied carbonate rocks was -0.91 to -0.01%. Extremely low values of S238U (-0.91%, -0.9%, and -0.84%), which were found in a number of samples from the lower part of the section, are interpreted as the result of postsedimentation processes affecting the rocks. In the overlying sediments, the range of S238U variations is smaller from -0.49 to -0.01%. Here, regular “weighting” of the U isotopic composition observed upwards through the section indicates an increase in the reduction conditions at this time (about 550 Ma) in the paleobasin. This conclusion is consistent with the elevated concentrations of U, Mo, and V in the Late Ediacaran sedimentary rocks of the region studied.
Geophysics
Geomagnetic field disturbances from the fall of the Lipetsk (june 21, 2018) and Chelyabinsk (february 15, 2013) meteorites
Abstract
Based on the Chelyabinsk (February 13, 2013) and Lipetsk (June 21, 2018) events, disturbances in the Earth's geomagnetic field, which were induced by the fall of these meteorites, were studied. Based on the data provided by geomagnetic observatories of the INTERMAGNET network and the mid-latitude Mikhnevo geophysical observatory (IDG RAS), it was established that the fall of meteorites through the Earth's atmosphere, in general, induces geomagnetic disturbances of up to 5 nT at distances up to 2700 km from the impact point of a cosmic body; the maximum effect is reached with a delay time ranging from ~5 to ~10 min, and the duration of the period of the induced geomagnetic field disturbances varies from ~5 to ~20 min. The estimation dependencies of the amplitude and duration of induced geomagnetic disturbances from a distance from the meteorite impact points are proposed.
Biochemistry, biophysics, molecular biology
Dipeptide mimetic of the bdnf loop 4 possesses analgetic activity
Abstract
Previously, we synthesized a dimeric dipeptide mimetic of the brain-derived neurotrophic factor (BDNF) loop 4, GSB-106, which, similarly to BDNF, activated TrkB, PI3K/AKT, and MAPK/ERK. When administered systemically, it exhibited neuroprotective, antidepressant, and antidiabetic activities and stimulated neurogenesis and synaptogenesis. In this study, we established that GSB-106 also exhibits the analgesic activity, typical for BDNF, which was revealed in rats in hot plate and tail flick tests 0.5–48 h after intraperitoneal injection at doses of 0.1 and 1 mg/kg.
The generation of the human mab RabD4 specific to the rabies virus glycoprotein and characterization thereof
Abstract
We generated a novel human neutralizing human mAb RabD4 against rabies virus glycoprotein using in vitro stimulation human peripheral B cells produced from immunized donor. It was revealed that the human mAb RabD4 demonstrated high antigen-binding activity and virus-neutralizing activity in the FAVN test with the CVS-11 rabies virus.
Detection of taxuyunnanin c in suspension cell culture of Taxus canadensis
Abstract
This is the first study to isolate the taxoid taxuyunnanin C (group of 14-hydroxylated taxoids) from the biomass of suspension cell culture of the Canadian yew (Taxus canadensis). According to available data, this is the first report of the presence of nonpolar (polyacylated) forms of 14-hydroxylated taxoids, including taxuyunnanin C, in T. canadensis.
Natural dicarbonyls inhibit peroxidase activity of peroxiredoxins
Abstract
It has been established that the activity of recombinant human peroxiredoxins (Prx1, Prx2, Prx4 and Prx6) inhibits by natural dicarbonyls formed during free radical peroxidation of unsaturated lipids (malonic dialdehyde) and oxidative transformations of glucose (glyoxal, methylglyoxal). The possible role of peroxiredoxins activity decreasing under oxidative and carbonyl stress is discussed as an important factor that includes molecular mechanisms of vascular wall damage in atherosclerosis and diabetes mellitus.
General biology
Taurida cave, a new locality of the early pleistocene vertebrates in Crimea
Abstract
A study of the association of vertebrates from the Pleistocene deposits of the Taurida karst cave discovered in 2018 in the central Crimea (Belogorsky district, Zuya village) showed its correlation with the Late Villafranchian faunas of the Eastern Mediterranean and an approximate age of 1.8–1.5 Ma.