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Compensation for near-surface heterogeneity is an important part of the seismic reflection method. The problem is solved by continuing the observed wavefield to a horizontal datum. Traditionally, two reflection traveltime curves determined from survey and datum lines are related by static shift corrections. In this paper, we solve a continuation problem in which the relation between the traveltimes of the observed and continued wavefields is given by the root-mean-square velocity equation for a two-layer earth model. A comparative analysis is made for the two methods of compensation for surface heterogeneity due to the variable altitude of the ground surface.

This paper presents a comparative analysis of the contents of heavy metals (HM) in the water, suspended matter (SM), and bottom sediments (BS) of the Ob river based on the results of long-term monitoring. The spatial distribution of metals along the middle and lower course of the Ob river is affected by its large tributaries such as Tom', Chulym, and Irtysh and by the Novosibirsk reservoir, as well as by large cities (Novosibirsk, Tomsk, and Nizhnevartovsk). The metal distribution at the interface between water and bottom sediments depends on the hydrological and hydrochemical conditions and is the major factor that is responsible for the higher contents of heavy metals in the bottom sediments of the Novosibirsk reservoir compared with the channel and still water lines of the river. The calculated concentration factors depend on the nature of the metal; the least factors were obtained for lead and zinc. Previous data obtained for the Ob reservoir and the upper Ob in general are discussed.

Methods for utilization of liquid and solid wastes of soda production are reviewed. The possibility of flooding oil fields with distiller fluid is examined. A landfilling technique is described whereby distiller fluid is injected into deep horizons. Utilizations of distiller fluid in asbestos-cement and white black productions are discussed. From soda production sludge one can manufacture building materials and oil-well cement materials for cementing wells under stringent mining and geological conditions.

Ultradisperse tetrafluoroethylene powder obtained by thermo-gas-dynamic method (FORUM TM material) was studied by derivatography, mass spectrometry, and differential scanning microcalorimetry. Thermal decomposition of FORUM and its thermophysical properties differ significantly from those of commercial PTFE. The temperature range of decomposition increased more than fourfold: 465-595^oC for PTFE, and 70-550^oC for FORUM. Thermal decomposition of FORUM gave a wide spectrum of molecular fragments with atomic weights from 31 up to 881. In the crystalline phase, there are no phase transitions characteristic of commercial PTFE samples; at the same time, the melting and transformation points in the amorphous part of the polymer are shifted.

The crystal structures and electronic properties of magnesium and calcium nitrates, magnesium nitrate hexahydrate, and calcium nitrate tetrahydrate are studied at the density functional theory level by a hybrid functional in the basis set of localized atomic orbitals using the CRYSTAL14 program code. Atomic structural parameters, atomic charges, bond populations, energy and electron spatial distributions are calculated. The mainly electrostatic nature of interactions between nitro groups and water molecules is shown. The spectrum of the density of states of crystal hydrates, in comparison with nitrates, contains additional bands due to the presence of water. In the spectra of unoccupied states a gap is observed: the anionic gap is ~6.5 eV and the cationic gap is ~8.8 eV.

By the structural representation of a chemical reaction in the form of a condensed graph a model allowing the prediction of rate constants (logk) of Diels-Alder reactions performed in different solvents and at different temperatures is constructed for the first time. The model demonstrates good agreement between the predicted and experimental logk values: the mean squared error is less than 0.75 log units. Erroneous predictions correspond to reactions in which reagents contain rarely occurring structural fragments. The model is available for users at https://cimm.kpfu.ru/predictor/.

The structural and electronic properties of semiconducting BC₁₉ and AlC₁₉ heterofullerenes as adsorbents for toxic small gas molecules (H₂S and SO₂) are determined by DFT. Structural parameters, energy gaps, natural population analysis, partial density of state, dipole moments, and vibrational frequencies were extracted. The adsorption process and sensitivity to the gases are increased by doping with B or Al. The results show that AlC₁₉ is the most sensitive structure. The good sensing of AlC₁₉ is related to high charge transfer upon gas adsorption. Adsorption of the H₂S on the BC₁₉ has negligible effects on the electronic properties, to be categorized as "harmless adsorption". H₂S is weakly adsorbed on BC₁₉ and AlC₁₉. The H₂S and SO₂ molecules act as electron donating and electron withdrawing molecules, respectively. Notably, the adsorption processes are highly exothermic. In general, BC₁₉ is more reactive than C₂₀ and AlC₁₉ is the most reactive cage. This provides a theoretical basis to fabricate B- and Al-doped C₂₀-based gas sensors.

The spin Hamiltonian parameters (g factors, hyperfine structure constants and superhyperfine parameters) and local structures for Ag²⁺ centers in AgCl and KCl crystals are theoretically studied using the high-order perturbation formulas for a tetragonally elongated 4d⁹ cluster. The impurity centers undergo relative elongations (≈0.05 Å and 0.23 Å for Ag²⁺ in AgCl and KCl, respectively) along the C₄ axis owing to the Jahn-Teller effect. All the calculated spin Hamiltonian parameters show good agreement with the experimental data, and the ligand contributions to the spin Hamiltonian parameters are important and should be taken into account. The unpaired spin densities in the superhyperfine parameters are determined from molecular orbital coefficients based on the cluster approach, instead of being taken as the adjustable parameters in the previous treatments. Increasing tetragonal elongation from AgCl to KCl is attributed to a decrease in chemical bonding (or lower force constant) with increasing Ag²⁺-Cl distance.

Extraction complexes of Eu(III) and Am(III) with two 2,6-dicarboxypyridine diamide-type ligands L-A and L-B (Fig. 1) are studied by density functional theory (DFT). At both B3LYP/6-31G(d)/RECP and MP2/6-31G(d)/RECP levels of theory, the geometrical optimizations of the structures of the complexes can achieve the same accuracy and obtain the same geometrical configuration. At the B3LYP/6-311G(d,p)/RECP level of theory Eu³⁺ and Am³⁺ prefer to form [ML]³⁺ complexes under the solvation conditions, and the Am(III) complexes with L-A are more stable than the corresponding Eu(III) complexes. In the system with the ligand L-B, both [ML]³⁺ and [ML(NO₃)₃] species are very unstable.

Halogen and solvent effects on the conformational, vibrational, and electronic characteristics of thiophene-2-carbaldehyde (T2C, C₅H₄OS) and thiophene-2-carbonyl-halogens [C₅H₃XOS, X = F (T2C-F), Cl (T2C-Cl), and Br (T2C-Br)] are analyzed by the density functional theory (DFT) and time dependent density functional theory (TDDFT), using the B3LYP functional and the 6-31++G(d,p) basis set. Computations consider two conformations of the compounds in both gas phase and solution. The present study aims at the exploration of the halogen and medium effects on the stability, structural parameters, dipole moment, carbonyl stretching vibration, frontier molecular orbitals, ultraviolet (UV) and density-of-states spectra of the conformers. The atypical characteristics of fluorine and chlorine affecting the electrical-optical band gaps, chemical hardness, partial density-of-states plot, absorption band, and the highest occupied molecular orbital are observed correspondingly. The findings of this research will provide insight for future studies considering conformations analogous to the compounds studied.