No abstract available

No abstract available

No abstract available

[en] The problem of the stabilization of a semilinear equation in the exterior of a bounded domain is considered. In view of the impossibility of an exponential stabilization of the form e^-σt of the solution of a parabolic equation in an unbounded domain no matter what the boundary control is, one poses the problem of power-like stabilization by means of a boundary control. For a fixed initial condition and parameter k>0 of the rate of stabilization the existence of a boundary control such that the solution approaches zero at the rate 1/t^k is demonstrated

[en] The Zelenchukskaya radio survey has been initiated with coverage of 0.33 sr of sky in the zone 0⁰< or =delta< or =4⁰. Concurrent observations at 8.7- and 14.4-GHz frequency disclose 82 and 24 sources, respectively, six of which have not hitherto been recorded

[en] Laser tests were performed on first mirror (FM) prototypes manufactured from single crystal and polycrystal Mo and with reflective Mo coatings on Mo substrate. Data on laser damage thresholds under the influence of the frequency-operated pulsed YAG laser (1064 nm wavelength, 12.5 Hz repetition rate, 10-30 mJ per pulse energy, 12 ns pulse duration) were obtained for single laser shot and after about 2.2x10⁵ laser shots. The output beam of the laser operating in the TEM_oo mode has a Gaussian profile. The single shot damage thresholds were measured and were equal to 2±0.4 J/cm² for polycrystal Mo and Mo/Mo mirrors, 3±0.5 J/cm² for single crystal Mo mirror. The long-time effect of frequency-operated YAG laser on mirror reflectivity was studied. It was shown that diffusion scattering is a very sensitive instrument to check the surface condition. Different types of Mo mirrors show various values of multipulse laser damage threshold. It may be connected as with initial quality of the surface and with different structures of the reflection layer for investigated samples of Mo. The degradation of a single crystal Mo mirror under multiple pulse laser irradiation is described with good accuracy by a predictive model for multipulse laser damage of metal mirrors [Appl. Optics 30-36 (1991) 5239] up to 1.5x10⁵ laser pulses

[en] In 1972, V. Keilis-Borok and I. Gelfand introduced the phenomenological approach based on the morphostructural zoning and pattern recognition for identification of earthquake-prone areas. This methodology identifies seismogenic nodes capable of generating strong earthquakes on the basis of geological, morphological, and geophysical data, which do not contain information on past seismicity. In the period 1972–2018, totally, 26 worldwide seismic regions have been studied and maps showing the recognized earthquake-prone areas in each region have been published. After that, 11 of these regions were hit by earthquakes of the relevant sizes. The goal of this work is to analyze the correlation of the post-publication events with seismogenic nodes defined in these 11 regions. The test was performed using the NEIC earthquake catalog because it uniformly defines the location and magnitudes of earthquakes over the globe. The ArcMap facilities were exploited to plot the post-publication events on the maps showing the recognized seismogenic nodes. We found that about 86% of such events fall in the recognized seismogenic nodes. The performed test proved the sufficient validity of the methodology for identifying areas capable of strong earthquakes and confirms the idea on nucleating strong earthquakes at the nodes.

[en] The influence of UV-irradiation by an XeCl excimer lamp on the physicochemical and catalytic properties of MFI-type high-silica zeolites modified by cobalt tungsto- and molybdobismuthates in the process of getting high-octane gosoline components is studied. It is show that the concentration of acidic centers can be increased by 76%; the arene yield, by 4-13 wt%; and the octane number of the products, by 2-3 points as compared with starting zeolite if cobalt tungstobismuthate heteropoly compound (1 wt%) is used as the modifier and the material is activated by UV-irradiation for 24 min. It is established that UV-irradiation of modified zeolites increases the concentration of acidic centers and decreases the adsorption capacity and specific surface area.

[en] Lowering of heavy element abundances Z according to modern determinations presents a problem of the solar modeling. We estimate settling rates of several heavy elements such as C, N, O, Ne, Si and Fe from the solar convective zone during evolution according to the Bahcall-Thoul technique. Acceleration of the heavy elements settling due to partial ionization and radiation-driven slowing are taken into account. Diffusion profile in modern Sun reveals a narrow region under the convective zone where heavy elements abundance remains almost the same due to specific effect of thermal diffusion. A rate of the elements settling from the convective zone depends on the convective zone depth and on the overshooting mixing around the low convective boundary. According to our results, diffusion settling is fairly small to explain entirely a low Z value in the photosphere.

[en] High-reflective Beryllium cover of ITER first wall (R≈30–60%) causes remarkable increase of divertor stray light component (DSL). Optical dumps are well-known solution for DSL attenuation. In this work few types of optical dumps have been examined both by modeling and experimental studies. Taking into account the limitations, induced by ITER first wall design, OD optimized design has been proposed which could decrease divertor stray light component by 10..100 times depending on incidence angle of light