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Experimental data on Fe-CaCO3 interaction at 6 GPa and 1273-1873 K are presented. The system models the hypothetical redox interaction in subducting slabs at the contact with the reduced mantle and a putative process at the core-mantle boundary. The reaction is accompanied by carbonatite melt formation. It also produces Fe3C and calcium wüstite, which form solid or liquid phases depending on experimental conditions. In iron-containing systems at 6 GPa, calcium carbonate melts in the range 1473-1573 K, which is consistent with aragonite disappearance from complex carbonate systems. The composition of calcium carbonate liquid is not influenced by metallic Fe. It corresponds to nearly pure CaCO3. Along the mantle adiabat or at slightly higher temperatures, nearly pure CaCO3 coexists with metallic iron or calcium wüstite. This hypothesis explains the coexistence of metallic iron and carbonate inclusions in lithospheric and superdeep diamonds.

We consider mineral assemblages and mineralogical and geochemical peculiarities of hypogene gold from the Khaak-Sair multistage low-sulfide gold-quartz ore occurrence in listwänites. Three productive substages of Au- and Ag-mineral formation have been recognized on the basis of mineralogical studies: gold-sulfosalt-sulfide-quartz, gold-mercury-quartz, and gold-selenide-telluride-sulfide-quartz. These substages were characterized by the following sequences of mineral formation: (1) ultrahigh-fineness gold → high-fineness gold → argental gold (medium- and low-fineness gold) → electrum + Ag-bearing and argental fahlores (up to 50 wt.% Ag) ± acanthite ± hessite; (2) high-fineness gold → Hg-bearing and mercurian gold → mercurian electrum → mercurian kustelite → Au-bearing mercurian silver; and (3) high-fineness gold → mercurian gold → mercurian electrum + naumannite + Te-bearing naumannite + fischesserite + tiemannite + hessite + coloradoite + Ag-bearing minerals of the galena-clausthalite series (up to 6 wt.% Ag) ± Se-cinnabar ± Se-imiterite. Productive mineral assemblages of the ore occurrence formed in the hypabyssal facies (depth ~1.5 km, P ~0.5 kbar) on the background of a temperature decrease from 290 to 160 °C and variations in f (O ₂), f (S ₂), f (Se ₂), and f (Te ₂).

In this paper, the solution of two-dimensional Maxwell’s equations is considered using the Laguerre transform. Optimal parameters of the difference schemes for the equations are obtained and presented. Numerical values of these optimal parameters are given. Second-order difference schemes with the optimal parameters provide an accuracy of the solution of the equations that is comparable to the accuracy of the solution using fourth-order schemes. It is shown that, when using the Laguerre transform, the number of optimal parameters can be reduced compared to the Fourier transform. This reduction leads to a simplification of the difference scheme and a reduction in the amount of computation, i.e., to efficiency of the algorithm.

We discuss the results of comparative analysis of finely and coarsely dispersed components of atmospheric aerosol optical depth (AOD), obtained according to data of SP sun photometer measurements in 14 regions of the Atlantic, Southern, and Arctic Oceans, and Far East seas. Average (over regions) values of the coarsely dispersed AOD component vary from 0.007 to 0.24, and average values of the finely dispersed AOD component vary from 0.015 to 0.25. Despite the fact that the two AOD components are independent in their origin and exist in a variety of combinations, the distributions of their average values exhibit joint growth from lowermost values in the Southern Ocean to maximal values in the zone of severe continental outflows (the Sea of Darkness and the Sea of Japan). Taking into account the natural specific features, we grouped the data with respect to a few types of maritime regions; and for each, we determined the most probable values of the coarsely dispersed component and two parameters (analogous to Ångström parameters), which characterize the finely dispersed AOD component.

In order to reduce the effect of time delay on the work of the adaptive system as a dynamic feedback system, a modern approach to the correction of turbulent distortions of optical radiation involves the use of new control algorithms for correcting mirror using prediction of phase distortion. Here the results of numerical simulation are presented.

The problem of second harmonics generation (SHG) of monochromatic spatially coherent paraxial radiation in homogeneous quadratic nonlinear uniaxial crystals is considered theoretically. It is assumed that the laser radiation is focused into a crystal by two crossed cylindrical lenses with different focal lengths. The aim of this study is to find dependences of optical focusing parameters on the primary radiation power. The work consists of two parts. Part 1 describes the mathematical apparatus required for the study. It is suggested to transform a set of nonlinear wave equations to a form, more convenient for further use. Some important particular cases are considered. An asymptotically exact analytical solution of the SHG problem is presented.

The problem of second harmonics generation (SHG) of monochromatic spatially coherent paraxial radiation in homogeneous quadratic nonlinear uniaxial crystals is considered theoretically. It is assumed that the laser radiation is focused into a crystal by two crossed cylindrical lenses with different focal lengths. The aim of this study is to find dependences of optical focusing parameters on the primary radiation power. The work consists of two parts. Part 2 presents main results of numerical calculations. It is shown that optimal focusing parameters first vary insignificantly as the primary radiation power increases. Then, beginning from a certain power value, which depends on the initial conditions of the problem, the SHG efficiency maximum becomes attainable at weaker and weaker focusing, and the value of the efficiency maximum monotone increases, probably tending to a value close to 100% under an infinite increase in the power.

In the article are examined some consequences of the axioms, accepted in the epistemic logic I. Hintikka, who concern the possibility for the subject to be in error relative to its own persuasions.

A symmetry is so an important tool in the search of unified theory that the developing of new scientific theory is closely linked with the one of the correspond group of symmetry. During the modern scientific theory search scientists face with a different understanding of the space symmetry in quantum field theory and in the theory of gravity, it prevents to find of a unified theory. The aim of the paper consists of the point to conceptual difficulties preventing to accord conceptions of different theories.

Philosophical and methodological criteria based on which it is possible make the conclusion about the degree of "jointness" of physical theory are given. For the analysis, the theory of superstring is selected. In this regard, the history of the theory of superstring and the theory of supersymmetry (SUSY) is briefly considered. The main philosophical problems of the theory are shown. Based on the cited philosophical and methodological criteria the author concludes that string theory is not the final theory of unification of fundamental interactions in physics.