SovietRxiv · Open Access in English
Rediscovering the Soviet scientific archive, in English
25357 full-text translations 14926 English PDFs 22539 abstracts
Showing 50 of 25357 papers
This paper addresses stochastic programming problems arising in static optimal control when control variables are only partially controllable and constraints must be satisfied with prescribed probabilities. It proposes a direct simulation method for the general case in which variable distributions m…
This paper evaluates the practical usefulness of Sobol pseudorandom sequences for multidimensional integration and related tasks requiring uniformly distributed trial points, such as search methods and experimental design. Numerical experiments on a BESM-4 computer compare Sobol sequences with stand…
This paper presents an implementation of a random search method with adaptive step size for constrained minimization of functions of several variables. It describes the algorithm, based on paired trial steps, step reduction after unsuccessful searches, and occasional long steps to update the nominal…
This paper formulates modifications of the Monte Carlo method for the radiative transfer equation in terms of transformations of Markov random walk processes. It constructs the underlying Markov process for collision histories, defines additive trajectory functionals used as estimators, and states c…
This paper discusses the use of a problem-oriented hybrid computing system for solving three-dimensional Dirichlet problems for the Laplace equation by the Monte Carlo method, motivated by field calculations in charged-particle motion and electron optics. The proposed system combines analog white-no…
This paper calculates the transport characteristics of positrons with initial energies from 0.23 to 1.0 MeV in absorbers of different atomic number, focusing on depth distributions of stopped particles and absorbed energy. Using a one-dimensional beta-particle transport formalism in the continuous-s…
This paper proposes a digital-computer method for solving finite, generally nonlinear operator equations of the form Ax = 0. It reformulates the problem through the residual norm functional and derives a system of ordinary differential equations whose trajectories follow the normals to nested level …
This paper presents an experimental and computational procedure for determining stress distributions during cold forward extrusion of strain-hardening metals. The method combines hardness measurements, deformed grid analysis, finite-difference evaluation of strain increments, and calculation of stre…
The paper considers the problem of replacing a continuous function on a finite interval by its best uniform approximation from a chosen finite-dimensional family of continuous functions. After recalling the classical Chebyshev formulation and related polynomial cases, it formulates the approximation…
This paper formulates a sequential experimental design problem for choosing observations that both discriminate among several linear hypotheses and refine the parameters of the true model. It introduces a duality-based functional combining a discrimination criterion with a D-optimality term, weighte…
The paper studies the choice of the regularization parameter alpha in Tikhonov-type methods for ill-conditioned systems of linear algebraic equations with perturbed right-hand sides. Using the discrepancy principle and spectral norm estimates, it derives an upper bound for alpha in terms of the matr…
This paper examines the absolute compression constant, defined as the molar volume of a compound divided by the sum of the molar volumes of its constituent elements, as a structural and physical parameter for alkali metal halide single crystals. Using tabulated data for lithium, sodium, potassium, r…
A remote measurement setup is described for determining elastic constants and internal friction of alkali metal halide single crystals placed in an irradiation zone. The apparatus uses a resonance method with a two-component quartz vibrator, coaxial connections, shielded mechanical holders, and freq…
Elastic constants and related elastic coefficients of NaCl, NaBr, and NaCl, NaBr solid solution single crystals of several compositions were measured by a pulsed ultrasonic method at 2.5 MHz over 80 to 300 K. The study determines \(C_{11}\), \(C_{12}\), \(C_{44}\), compliance coefficients, the aniso…
Elastic properties of single crystals in the KCl and KBr solid solution system were investigated at low temperatures to extend earlier room temperature and high temperature data. Using a pulsed ultrasonic method at 2.5 MHz, longitudinal and transverse wave velocities were measured from 80 to 300 K f…
The study examines the thermal stability of F and V1 color centers formed by X-ray irradiation at liquid nitrogen temperature in KCl, KBr, and KCl-KBr solid solution crystals. Using thermal bleaching and thermally stimulated luminescence during linear heating, the authors compare destruction tempera…
Thermodepolarization currents were measured in pure and impurity-doped KCl and KBr single crystals between 80 and 300 K to investigate low-temperature polarization relaxation in alkali-halide crystals. Using linear heating after polarization, the study recorded TDP spectra and estimated activation e…
This study examines the thermoelectric properties of pyrite from quartz veins and near-ore altered rocks in several Siberian, Ural, Transbaikalian, and Far Eastern gold deposits of vein, stockwork, and contact-metasomatic types. Thermo-EMF measurements at a constant temperature of 250°C show that mo…
This study examines how electron irradiation alters the electrical conductivity of LF-2 forsterite ceramics and emphasizes the need to correct measurements for radiation-stimulated thermocurrents produced by internal electrical inhomogeneities. Disk specimens were irradiated with 1.2 MeV electrons a…
This paper investigates the fracture behavior of NaCl and LiF optical single crystals under pulsed radiation from a neodymium glass laser in modulated and free-running regimes. The authors irradiated annealed single-crystal specimens and analyzed macroscopic damage patterns together with dislocation…
This study examines how ionizing radiation changes the electrical conductivity of calcium fluoride crystals with different growth histories and impurity contents. Conductivity and thermoluminescence were measured after irradiation at room temperature with 1.2 MeV electrons and 4.5 MeV protons over d…
This study examines how yttrium and rare earth impurities affect the formation of intrinsic radiation defects in calcium fluoride crystals irradiated by 4.5 MeV protons and 1.2 MeV electrons. Optical absorption spectra and radiation induced density changes were used to follow the accumulation of F a…
This study examines how specific pressing pressure affects the optical transparency and microhardness of pressed NaCl, KCl, and KBr tablets intended for infrared spectroscopic applications. Fine salt powders were vacuum pressed at 120°C under pressures from about 3000 to 12000 kg/cm², and the result…
This paper examines the physical meaning and measurement of the electromotive force of high-voltage polarization in ionic dielectrics. The authors analyze conditions under which space charge formation can produce such an emf, distinguishing these cases from other sources of absorption current, inclu…
This paper evaluates a contactless torque method for measuring the electrical properties of spherical alkali halide crystals across very low frequencies and elevated temperatures. Building on Ogawa’s theory, the authors derive the relations between torque in a rotating electric field, conductivity, …
This paper examines stored energy in ionic crystals, especially alkali-halide dielectrics, as a thermodynamic measure of instability produced by temperature changes, mechanical and electric fields, and irradiation. It develops a defect-based interpretation in which stored energy is associated chiefl…
This study examines how sodium modifier ions affect the radiation-optical behavior of alkali borate glasses irradiated with 1.2 MeV electrons. Optical absorption, thermoluminescence, and thermodiffusion concentration emf measurements were compared for vitreous boron oxide and sodium borate glasses w…
The paper derives practical formulas for characterizing hydrodynamically imperfect wells by comparing pressure drop expressions for imperfect and ideal wells. It first obtains an expression for the reduced well radius, defined as the radius of a perfect well with the same inflow, and illustrates tha…
This study examines the alkaline hydrolysis of O-methyl-O-ethyl thiophosphates derived from phenolic model lignin compounds, with attention to the stability of the P-OAr bond and its relation to phenol acidity. Hydrolysis kinetics were measured in aqueous ethanol with sodium hydroxide by photocolori…
The study examines selective phosphorylation of alcoholic hydroxyl groups in lignin model compounds using O-methyl-O-ethyl chlorothiophosphate, with attention to the effects of base, solvent, and aromatic substituents. Aromatic alcohols and phenol alcohols were reacted in anhydrous organic solvents …
This study examines how temperature affects the reduction of acetyldiphenyl with aluminum isopropoxide in p-xylene, a reaction that yields both diphenylmethylcarbinol and the vinyl compound phenylstyrene. Experiments were conducted at 80, 100, and 120°C using a 1:1 ratio of ketone to reducing agent,…
The study examines how the ratio of aluminum isopropoxide to acetyldiphenyl affects phenylstyrene formation and reaction order during reduction in a xylene medium at 100°C. Experiments were conducted at acetyldiphenyl to aluminum isopropoxide ratios of 1:1, 1:3, and 1:6, with ketone concentration me…
This study examines tar formed during thermal decomposition of peat in peat-ore briquettes under experimental shaft-furnace smelting conditions, comparing it with tar from laboratory peat semicoking. The tars were characterized by water and ash content, group and fractional composition, while neutra…
This paper examines the extension of a one-stage direct iodination method to selected nitroaromatic substrates, addressing the limited availability of iodine-containing aromatic intermediates. Using iodine in the presence of a sulfuric and nitric acid mixture, with acetic acid and carbon tetrachlori…
The study examines the radical polymerization of 3-chloro-9-vinylcarbazole, a substituted 9-vinylcarbazole of interest for heat-resistant dielectric and electrophotographic materials. Polymerization was carried out in bulk, solution, and suspension using benzoyl peroxide or azobisisobutyric acid din…
This paper reports the preparation of iodine-containing monoazo dyes intended to explore the effect of halogen substitution on dye properties. The authors synthesized p-iodoaniline and 4,4'-iodoaminodiphenyl derivatives, diazotized them, and coupled each diazo component with phenol, beta-naphthol, c…
This paper develops the PPN polarographic method for studying slow, irreversible discharge and ionization processes of complex ions at a stationary graphite electrode, where mercury electrodes are unsuitable for noble metals. The authors derive relations connecting anodic and cathodic peak potential…
A stripping polarographic procedure is developed for determining nanogram quantities of gold in rocks, ores, minerals, and natural waters using accumulation on a graphite electrode. The authors examine supporting electrolytes and find that 1 M potassium bromide with 0.03 N hydrobromic acid gives rep…
This study examines why foam glass synthesized from nepheline-containing glass develops interconnected pores and high water absorption despite otherwise favorable properties. Nepheline glass was prepared from Uzhur deposit rock with additives, foamed under varied temperatures, times, heat treatments…
This study examines phase formation and polymorphic stability in the solid-state synthesis of magnesium metasilicate from stoichiometric silica and magnesium carbonate, with particular attention to protoenstatite and its transformation to clinoenstatite. Samples were fired between 1100 and 1450°C, w…
This study examines whether electrophysical measurements can clarify the mechanism of photolysis in solid ionic compounds, focusing on heavy-metal azides and their sensitization by organic dyes. The authors compare photochemical decomposition with photoconductivity and photopotential measurements in…
This study examines how sodium carbonate and calcium chloride additives affect the reaction of zircon concentrate with calcium carbonate at industrially relevant zircon to calcium oxide ratios. Differential thermal analysis was used to assess additive amounts from 1 to 8 percent by charge weight, an…
This study examines quantitative relationships among light alkane hydrocarbons in gasoline fractions of oils from several fields in Tomsk Oblast. Using capillary chromatography, the authors compare isomer distributions for hexanes and methyl-substituted paraffins, finding a generally stable order of…
This study examines thermal internal stresses in photosensitive semiconducting polymer coatings on metal substrates, a factor affecting coating quality, adhesion, and suitability for flexible electrophotographic applications. Polymer films were cast on brass plates of different thicknesses, heated t…
This study examines the adhesion of several photosensitive, semiconducting polymers to brass and aluminum substrates, a property important for electrophotographic coatings. Because the polymer films were brittle, adhesion was measured by peeling thin metal foil from the polymer layer using Deryagin’…
This study examines phase transformations in high-purity Onot and Algui talcs during heating from 800 to 1500°C, addressing conflicting views on the decomposition of talc and the stability of resulting magnesium metasilicate phases. Using X-ray diffraction, high-temperature X-ray analysis, petrograp…
A photometric procedure is described for determining trace aluminum in high-purity iron using methylthymol blue, which forms a colored 1:1 complex with aluminum at pH about 3.3. The method decomposes the iron sample in hydrochloric acid, oxidizes iron, removes it by extraction with diethyl ether, fo…
This paper reports an extension of a one-step iodination and nitration method for aromatic compounds using iodine together with a sulfuric and nitric acid mixture. The authors applied the reaction to fluoranthene and fluorenone-5-carboxylic acid, obtaining the previously undescribed products 3-iodo-…
This paper examines cementation as an interference in amalgam polarography with accumulation and chronopotentiometric determination of trace substances, focusing on a stationary spherical mercury electrode. A kinetic diffusion model is developed for an irreversible cementation reaction under stirred…
