The surface-layer composition of Pb–Na alloys is studied using X-ray photoelectron spectroscopy and scanning electron microscopy with a device for local chemical analysis. It is shown that lead and sodium are present in the surface, both in the metallic and in the oxide states. Fragments of hydrocarbon compounds contaminating the sample surface are found in larger quantities in the surfaces of the studied samples. Surface treatment with an ion beam only reduces the thickness of the contaminated layer. In contrast to the method of X-ray photoelectron spectroscopy, the scanning-electron-microscopy method makes it possible to detect elements that are part of the substrate in the surfaces of the studied samples: Ca, Fe, Ti, Si and Ni. It is observed that the position of the sodium-adsorption peak with a temperature increase shifts on the composition scale. This is associated with the dissociation of large quasi-molecular formations that appear on the surface at lower temperatures in the form of interaction products of Pb, Na, and elements present on the surface of the substrate used, as well as fragments of hydrocarbon compounds contaminating the surface of the alloys under study.

The article shows that the national interests of Russia require an active policy for the development of regional universities because of their role in solving the basic problems of the country such as the consolidation and modernization of the Russian society.

The polytherms of density, the surface tension of melts of the Cu–Al system and wetting angles of Ni–Cr, Co–Cr, 25Cr18N9C2 stainless steel and titanium substrates are studied using the lying drop method. The drop contour is processed using modern information technologies, in particular, using the ImageJ software package. Equations for the polytherms of density and surface tension of the melts of the Cu–Al system are obtained. The Cu–Al melts are shown to wet the substrates at 1000 K or more. The features of the temperature dependences of the wetting angles are revealed.

Abstract—The phase composition of a film obtained by the method of the simultaneous electric arc sputtering of graphite and chromium from two evaporators is studied by Raman and X-ray photoelectron spectroscopy. Analysis of the chemical state of atoms by X-ray photoelectron spectroscopy is performed before and after cleaning the surface of the film by bombardment with argon ions. Raman spectroscopy reveals amorphous carbon and graphite nanoparticles in the film. Taking into account the dependence of the ratio of the intensities of the D and G peaks in the spectrum on the size of crystallites, the linear size of carbon nanostructures is estimated as ~6 nm. According to X-ray photoelectron spectroscopy, the formation of chromium carbide in the film with a stoichiometry of Cr6.8C3.2, which is close to the stoichiometry of Cr7C3 heptachromium tricarbide, as well as Cr2O3, Cr–O–C and Cr(OH)3 chromium oxides, is found.

A study of the effect small additions of sodium have on the surface tension (ST) of Pb–Na binary melts reveals a sharp drop in ST in the range of 0.2–0.25 at % Na. Calculations of the sodium adsorption isotherm indicate a maximum in the same region of the composition. An explanation for this effect is proposed. It is shown that the composition of the melt at which the maximum of sodium adsorption is observed is determined by the product of coefficient of displacement γ and the exchange parameter of the surface layer of a melt with volume F. It is established that raising the temperature of the melt results in partial decomposition of quasi-molecular formations with participation of sodium, filling of the surface of the melt, and a shift in the position of adsorption maximum toward an increase in the content of sodium.

Методом лежащей капли изучена температурная зависимость краевого угла смачивания сплавов Pb - Na разной концентрации на подложках из Co - Cr, Ni - Cr, нержавеющей стали 251892. Измерения проводились методом лежащей капли в широком интервале температур от 359°С до 800 °С в атмосфере чистого марки А. Показано, что значение угла смачивания уменьшается с увеличением температуры, наблюдаются пороги смачивания. The temperature dependence of the contact angle for Pb - Na melts of different concentrations on Co - Cr , Ni - Cr and stainless steel 25X18H9C2 substrate was studied by the method of a lying drop. Measurements were carried out by a lying drop method in the temperature range from 359 to 800 °C in an atmosphere of pure helium grade A. It is shown that the value of the wetting angle decreases with increasing temperature, wetting thresholds are observed.

The critical temperatures of alkali metals are calculated on the basis of refined data on temperature dependences of surface tension of alkali metals approximated with linear equations. It is shown that the calculated values of the critical temperatures of alkali metals are in satisfactory agreement with the experimental results and theoretical calculations available in the literature.

Polytherms of the density and surface tension of lead alloys with small additions of sodium in the heating mode from temperatures of melting of Pb–Na alloys up to 650°C in an atmosphere of pure He of grade A (99.995%) are studied using the large sessile drop approach. It is found that the density and surface tension fall as the temperature rises, and raising the content of sodium in the studied alloys to 4 wt % leads to a a substantial drop in surface tension.

The surfaces of polyphenylenesulfone samples with the addition of carbon fibers were studied by X-ray photoelectron and Auger-electron spectroscopy. The state of carbon atoms on the surface, the electronic structure, and the distribution of carbon fibers in the surface region as a function of the concentration of the additive were studied. It is shown that with 10 mass. % carbon fiber addition, the transformation of peaks is mainly associated with an increase in the number of carboxyl groups in the matrix, while with a carbon content exceeding 10 mass. %, the increasing role of differential vertical charging becomes the dominant factor. A further increase in the carbon fiber concentration leads to an increase in the conductivity of the bulk part and, consequently, to a decrease in the charge layer without carbon fiber, and therefore, to a decrease in the broadening effect of the C 1s carbon peak.

Geochemical study of water samples taken from the Malyi Mukulan and Bol’shoi Mukulan creeks and watercourses and trickling from the pile dike of tailing pond no. 3(1) of the Tyrnyauz tungsten–molybdenum plant has been carried out. Estimation of the degree of their polluting effect on the Baksan River was made.

Polytherms of density and surface tension of lead alloys with minor sodium percentages were studied in heating mode in a range from Pb-Na melting temperature to 650 degrees C under the atmosphere of pure Grade A He (99.995 %). It has been established that density and surface tension decrease with increased temperature, while increasing sodium content in the alloys to 4%wt leads to a significant decrease in surface tension.

In this paper, the task of obtaining new solders for brazing nickel and its alloys. Polyterms of wetting angle for Pb-Ni melts in the range from the melting point to 940 K on copper substrates and up to 900 K on aluminum were studied and wetting thresholds were detected: wetting of copper substrates starts at 640 K, and aluminum substrates are not wetted by the abovemelts.

In modern studies, experimental methods for estimating nonlinear elastic moduli are often replaced with calculations of these quantities in mathematical simulation. However, different reliable models and experiments give different values of nonlinear elastic moduli. This work proposes a poßsible solution to the problem of which sets of elastic moduli should be used to predict the properties of substances. Two sets of the second-({cαβ,γδ}), third-({cαβ,γδ}), and fourth-order elastic moduli ({cαβ,γδ,μη,τρ}) of hexagonal Gd crystal proposed in the literature are considered as examples. The elastic moduli are defined as partial derivatives of the nonequilibrium Landau potential ΦL {uαβ{ with respect to components of the tensor of homogeneous deformation of the crystal (Ü). Necessary information about the nonequilibrium Landau potential as a function of {uαβ{ is given in the second section. An analytical way of deriving relationships between generally independent values of nonlinear elastic moduli caused by symmetry is proposed in Sections 3 and 4. The approach is based on using the integral rational basis of invariants (IRBI), which have the form of polynomials {uaß{. Aspects of the theory of phase transitions based on IRBI are discussed in Section 3. The set of polynomials of the second, third, and fourth order included in the list of basic invariants {J i (P)}, and the form of Landau potential Φ({J i (P)}, are clearly defined. The forms of the chosen dependences {J i (P)} and (ΦL{J i (P)}) are defined in Section 4 to compare the results from different works. Once the forms of Landau potential ΦL{J i (P)} and ΦL{uαβ} are defined, they are compared. The comparison results allow derivation of the nontrivial relationships between the components of the third-C III and fourth-rank elastic moduli tensors C IV due Gd hexagonal symmetry. Two different sets of calculated elastic moduli of Gd crystals, found in two different works, are given in Section 5. The criteria for selecting the most suitable set of numerical values of elastic moduli are described in Sections 6 and 7. One criterion is a comparison of load limits calculated from isothermal Gd elastic moduli and experimentally determined numerical values of the limits of stability of a certain Gd phase. In the last section, we show how the criterion based on comparing the phase stability limits allows us to dertermine which sets of third-rank elastic moduli should be used in, e.g., predicting Raman spectra.

Anomalous concentrations of numerous major and minor elements significantly exceeding the threshold limit values (TLV) for drinking water were registered in the area of the Tyrnyauz Tungsten–Molybdenum Combine (TTMC). The maximal excess of the TLV (by one or two orders of magnitude) were obtained for Mo (up to 11 mg/L), W (4.4 mg/L), As (1.5 mg/L), Mn (8.4 mg/L), and Tl (up to 3.3 μg/L) in water of the Bolshoi Mukulan Brook flowing through the mines and three brooks flowing out from the base of the embankment of the tailing store no. 1. They are the major pollutants for water of the Baksan River. Upon flowing out to the plain, water of the Baksan River shows significant excess of the TLVs (in summer) for Al, Fe, Mn, Be, Si, Ti, Tl, and Hg.