[en] The research problem of substituting existing hypotheses by a well-defined re modeling of the geological processes, which, in its turn, initiate and govern the formation of hydrothermal gold-ore deposits, is becoming more and more relevant. The four existing hypotheses - granitogene, basaltogene (magmagene), metamorphogene, and polygene have been considered and discussed. The interpretation of different hypotheses and analysis of substantiating facts showed the inconsistency of above-mentioned hypothesis-approaches. Up-dated petrological, petrochemical, geochemical data proved the following: generation of metal-bearing fluids in sources of moderate alkali-basalt melts during the late basalt formation stages show recycling Late Riphean to Late Paleozoic convergent antidromic granite diorite dolerite magmatic complexes

[en] The mechanical properties of brickwork depend on a multitude of different factors such as components properties, their specific volume content, relative location and the quality of adhesion bonds. An important feature of the masonry is the high degree of these factors indeterminacy and the wide scatter of the experimental data in the testing of bricks and mortar. We present a mathematical model that allows determining the mechanical characteristics of the masonry based on the mechanical properties of the brick and mortar, their specific volume content in a fuzzy setting in this paper. All input parameters, which allow to obtain interval estimates of stresses and deformations of the brickwork fragment, are determined by membership functions. The simulation results are compared with the experimental data of other authors. (paper)

[en] The results of studies of optical reflection in the far- and mid-infrared spectral regions are reported. The reflectance of five Bi_2Se_3 topological insulator films grown by molecular-beam epitaxy on Si(111) substrates is measured. The characteristic parameters of phonons and plasmons are determined by means of dispersion analysis for multilayer structures. It is found that the plasma frequency in a layer close to the Si–film interface is noticeably higher than that in the film bulk. Calculations of the loss function show that plasmon–phonon coupling plays an important role in Bi_2Se_3 films. The attenuated total internal reflection method is used to determine the frequency of the surface plasmon–phonon mode.

[en] The narrow-gap II-VI and IV-VI alloys are convenient objects for studying the electron-phonon interaction. However, the concentration of free carriers in the IV-VI alloys is rather high (∼10¹⁸ cm^-3), which complicates studying this effect, by the optical reflection method. The concentration of free carriers in the narrow-gap Hg_1-xZn_xTe alloys is considerably lower (∼10¹⁶ cm^-3). Therefore, the plasma component exerts less effect on the lattice reflection spectrum. The reflection spectra of Hg_1-xZn_xTe crystals with x = 0.1-1 were studied in the far-IR region in the range of 30-700 cm^-1 at 40-300 K. Using the dispersion analysis and the Kramers-Kronig method, the frequencies of the TO phonons of the HgTe-like and ZnTe-like modes were determined depending on the composition. It is shown that the reconstructed phonon spectrum involves two modes. The temperature dependences of the frequencies of the TO phonons and the damping parameter were measured for the narrow-gap alloy with x = 0.1 in the range of 80-200 K. A decrease in the frequency of the TO phonon of the soft mode in the vicinity of the inversion point of the bands at T = 110 K was for the first time found by optical methods. The damping parameter slightly increases in the vicinity of this temperature. The result obtained qualitatively agreed with the theoretical model of Kawamura et al., which makes allowance for the effect of the electron-phonon interaction on the frequency of the soft mode in the IV-VI compounds

[en] The reflectance spectra of the topological insulator Pb_1–xSn_xSe (x = 0.2, 0.34) films grown by molecular-beam epitaxy on a ZnTe/GaAs substrate are measured in the range of 12–2500 cm^–1 at room temperature. Using dispersion analysis, the frequencies of transverse optical phonons, plasma frequencies, highfrequency permittivities, and layer thicknesses are determined. In the quasi-steady-state approximation, the interface mode frequencies of the four-layer structure are calculated as a function of the overlap parameter χ₁ (0 ≤ χ₁ ≤ 1). The parameter describes the degree of overlap of two interface modes localized at planes bounding the layer to the right and left. The existence of interacting interface modes in the structure makes its spectrum different from the sum of component spectra. These differences manifest themselves in the experiment. The conditions of the interaction of interface modes with IR radiation are discussed.

[en] The infrared reflection spectra of PbTe/CdTe multilayer nanostructures grown by molecular-beam epitaxy are measured in the frequency range of 20–5000 cm"−"1 at room temperature. The thicknesses and high-frequency dielectric constants of the PbTe and CdTe layers and the frequencies of the transverse optical (TO) phonons in these structures are determined from dispersion analysis of the spectra. It is found that the samples under study are characterized by two TO phonon frequencies, equal to 28 and 47 cm"−"1. The first frequency is close to that of TO phonons in bulk PbTe, and the second is assigned to the optical mode in structurally distorted interface layers. The Raman-scattering spectra upon excitation with the radiation of an Ar"+ laser at 514.5 nm are measured at room and liquid-nitrogen temperatures. The weak line at 106 cm"−"1 observed in these spectra is attributed to longitudinal optical phonons in the interface layers

[en] The frequencies of the vibrational modes of CdTe and CdSe quantum dots and CdTe/CdSe core/shell nanoparticles prepared by the colloidal chemistry method are determined using IR transmission and IR reflection spectroscopy. The experimental IR transmission spectrum of CdTe and CdSe nanocrystals exhibits a broad minimum located between the frequencies of the transverse (TO) and longitudinal (LO) optical phonons of bulk CdTe and CdSe crystals. The frequencies of the modes for ensembles of CdTe and CdSe quantum dots are considerably shifted toward lower frequencies as compared to those calculated for single quantum dots. This is explained by the dipole-dipole interaction between quantum dots. The frequencies of modes for the structures with core/shell nanoparticles differ little from the calculated frequencies. This suggests a weakening of the interaction in these structures due to the enhancement of dielectric screening