SovietRxiv · Open Access in English
Rediscovering the Soviet scientific archive, in English
25456 full-text translations 14926 English PDFs 22540 abstracts
Showing 50 of 25456 papers
This paper studies a class of invariant first order systems that become hyperbolic for a Lorentz signature metric, focusing on their structure after separating a distinguished time coordinate. The system is rewritten in terms of spatial exterior differentiation and its adjoint, and it is shown that …
This paper addresses the inverse scattering problem on the half-line for second-order differential equations whose coefficients include an inverse-square singularity, under weighted integrability assumptions on the real potential. Using a method related to the Agranovich and Marchenko approach, it g…
This study examines how temperature affects the fine structure of the titanium K absorption edge in barium monotitanate and tetratitanate, with emphasis on the region near the ferroelectric Curie point of BaTiO3. X-ray absorption spectra were recorded photographically using a focusing tube spectrogr…
This paper examines the stability of a plasma confined in a magnetic dipole field, motivated by mirror trapping in the Earth’s magnetic field and the observed radiation belts. Using the hydrodynamic approximation and the energy principle for small perturbations, the authors derive a stability condit…
The study examines reactions of sodium cyclopentadienide with alkoxytitanium chlorides as a route to cyclopentadienyl alkoxy derivatives of titanium. Mono-cyclopentadienyl triethoxy and tri-n-propoxy titanates, a bis-cyclopentadienyl ethoxy chloride, and mixed chloro-alkoxy cyclopentadienyl titanium…
This paper computes the centers of all connected simply connected noncompact simple real Lie groups, extending a method used by Dynkin and Onishchik for compact and complex simple groups. The argument realizes each real form through an involutive automorphism of a compact simple Lie algebra, proves …
This paper reexamines the motion of Encke Backlund’s comet during the 1898 to 1911 apparitions in order to derive a new estimate of Mercury’s mass from the comet’s close 1905 approach to the planet. The authors recompute planetary perturbations, including repeated recalculation after orbital improve…
This paper gives a sufficient operator-theoretic condition for solvability of the multidimensional moment problem. It considers tensor products of linear spaces with involution and commuting symmetric real operators, proving that if one operator is self-adjoint in each induced one-dimensional comple…
This paper reports the first preparation of organomagnesium compounds in the isoxazole series, using 3,5-dimethyl-4-bromo- and 3,5-dimethyl-4-iodoisoxazole under entrainment conditions with ethyl bromide. Reaction conditions were compared by carbonation to 3,5-dimethylisoxazole-4-carboxylic acid, sh…
The paper addresses the design of electrical prospecting apparatus capable of combining the productivity of transient-field methods with the noise immunity of multifrequency measurements. It analyzes the limitations of sequential fixed-frequency measurements and broadband transient recording, then p…
This study examines the relative reactivity of benzene and alkylbenzenes in olefin alkylation catalyzed by boron trifluoride phosphoric acid, addressing whether benzene homologs are generally more reactive than benzene. The authors compare alkylation by propylene, butylenes, isobutylene, and cyclohe…
The study examines the kinetics and reaction pathways of butane and butane, butylene mixtures over an alumina, chromia catalyst at 600 to 635 °C and atmospheric pressure. Flow experiments with binary mixtures of butane with butylene, butadiene, or hydrogen, and with butylene or butadiene diluted by …
The paper studies transient phenomena in continuous-time branching processes with finitely many particle types when the dominant characteristic root of the mean matrix tends to zero. For a compact class of indecomposable processes with uniformly bounded second and third factorial moments, it derives…
This note studies a singularly perturbed boundary value problem for the second order equation with a small parameter multiplying the highest derivative, in the case where the right hand side depends only on the unknown function and the independent variable. Under smoothness assumptions near the limi…
The paper formulates continuum equations for unsteady filtration of a homogeneous fluid in rocks with strongly developed fracturing, where explicit modeling of individual fractures is impractical. It represents the rock as two interacting porous media, a highly permeable fracture system and a lower …
This paper studies laws of large numbers for random variables associated with non-homogeneous Markov chains, allowing each variable to depend on a fixed finite number of consecutive time instants. Using Dobrushin-type coefficients of ergodicity, it derives variance bounds for sums of such variables …
This study examines reactions of diborane with butyl esters of diarylboronic and arylboronic acids in diethyl ether at room temperature. The authors show that diarylboronic acid esters react readily to give 1,2-diaryldiboranes, including diphenyl, di-p-chlorophenyl, and di-alpha-naphthyl derivatives…
This study examines how the cation in acetate salts influences anodic processes and product yields in Kolbe electrosynthesis on platinum electrodes. Polarization measurements with alkali, alkaline earth, ammonium, tetramethylammonium, and several variable-valence metal cations were combined with gas…
This study examines the addition of lithium diethyl- and dibutylphosphides to vinylacetylene, vinylmethylacetylene, and vinylethylacetylene, extending earlier work on analogous lithium amide reactions. The reactions were carried out in ether under argon, and the resulting tertiary phosphines were ch…
This note extends a modification of the Lobachevsky-Graeffe method for numerical solution of algebraic equations to cases in which roots have equal moduli and may be multiple, avoiding a preliminary separation of multiple roots. It derives how repeated Graeffe transformations and a small shift of th…
This paper investigates the fine structure of Rayleigh light scattering in acetone-water and methyl alcohol-water solutions in order to separate scattering contributions from different fluctuations and to determine hyperacoustic propagation velocities. Using a high-resolution Fabry-Perot interferome…
The study examines the catalytic activity of tungsten pentoxide in alcohol dehydration and in the dehydrogenation of methyl alcohol and tetralin under flow, low-conversion, approximately isothermal conditions. Using diluted catalyst and alcohol mixtures with reaction products, the authors determined…
This paper addresses the previously unknown cis isomer of the inner-complex divalent platinum salt with alpha-alanine, in the context of analogous glycine and alpha-aminobutyric acid complexes. The authors prepare potassium tetrakisalaninoplatinate, acidify the solution, and heat it to induce format…
The paper examines whether dimethylaminostyryl derivatives of acridine form colored molecular complexes with nitrobenzene, analogously to known donor, acceptor chromophoric systems. Absorption spectra were measured for several acridine anhydro bases in nitrobenzene and compared with spectra of the c…
This note studies metrically complete, sufficiently smooth Riemannian spaces possessing a pole, under the assumption of positive curvature, or more specifically positivity in two-dimensional directions tangent to geodesic rays from the pole. Using Fermi coordinates, associated two-dimensional surfac…
The paper studies when a symmetric operator in a Hilbert space completion of a topological vector space has a self-adjoint extension commuting with the self-adjoint closure of another commuting symmetric operator. It proves an extension criterion based on strong self-adjointness and a reality condit…
This study examines the destruction and reformation of natural protein structures during high-voltage electrodialysis through nonporous cellophane membranes. Using gelatin, myosin, denatured egg albumin, and edestin, the authors combine transfer experiments under varied temperature, concentration, v…
The paper studies entire analytic solutions of a class of partial differential equations that includes the heat equation and a mixed type equation, characterizing such solutions through series expansions and growth restrictions on an associated entire function. It formulates and solves a Cauchy prob…
This study examines the radicals formed during radiolysis of benzene, diphenyl, terphenyls, and ditolyls, and relates radical yields to molecular structure. Electron paramagnetic resonance spectra and accumulation kinetics were measured during irradiation by 1.6 MeV electrons at low and room tempera…
This note studies densely embedded ideals in abstract semigroups, extending earlier characterizations related to transformation semigroups. Using right and left shifts and their linked pairs, it constructs for a semigroup without equiacting elements a canonical semigroup in which the original semigr…
This study examines the vapor-phase catalytic hydrogenation of 2-alkyl-5-acylfurans over platinum on carbon at atmospheric pressure and 300 to 310°C, focusing on how carbonyl-containing substituents direct furan-ring hydrogenolysis. The authors show that cleavage occurs primarily at the C-O bond adj…
This note studies compactness, in the Fréchet metric, for families of surfaces of finite topological type lying in a bounded region and having uniformly bounded area. It shows that these Hilbert-type boundedness conditions are not sufficient by themselves, and formulates necessary and sufficient com…
The study examines the alkylation of 2-chloroanisole with propylene, butene-2, and cyclohexene using a boron fluoride, phosphoric acid catalyst, extending earlier work on haloanisole alkylation. Under conditions previously found favorable for 4-chloroanisole, propylene and butene-2 gave only the cor…
This paper examines why low-melting metal melts can either reduce or increase the fatigue strength of steel under cyclic deformation, focusing on surface-active effects and secondary physicochemical processes in surface layers. Fatigue tests on steel specimens with stress concentrators compare behav…
This study examines how molecular weight affects the fluorescence of high molecular weight compounds, including polymers with and without continuous conjugated chains. Fluorescence spectra were photographed and microphotometrically analyzed for diverse polymers, with detailed comparisons of polyphen…
The study examines the surface state of anodically polarized germanium during electrochemical etching in alkaline media, a problem relevant to semiconductor processing but previously investigated mainly in acidic solutions. Using cathodic charging curves for polycrystalline degenerate germanium in 0…
This paper examines the hydration hardening of sulfate binders with different cations, focusing on how crystallization kinetics govern the formation and strength of dispersed structures. Using heat evolution measurements, dissolution studies, suspension hardening tests, and microscopy, the authors c…
This note studies the numerical stability of the Ritz method for solving equations with positive definite operators in Hilbert spaces, focusing on how the choice of coordinate system affects the behavior of the coefficients as the number of terms increases. It reviews reliable coordinate systems, re…
This note generalizes Hopf’s classification theorem for maps from n-dimensional polyhedra to the n-sphere to the setting of uniformly continuous mappings of uniform n-dimensional triangulations. It introduces uniform chains, uniform homology, and the uniform group, then uses simplicial approximation…
This paper studies the motion of an incompressible electrically conducting viscous fluid between two parallel porous planes under a constant transverse magnetic field, with injection through one plane and suction through the other. The magnetohydrodynamic equations are reduced to coupled equations f…
This paper studies the index of boundary value problems for systems of harmonic functions in a three dimensional convex domain with elliptic first order boundary operators. It associates the problem with elliptic first order systems on the boundary surface, defines a characteristic through a bundle …
This paper develops a finite-difference formulation for short-range weather prediction using the complete hydrodynamic equations in pressure coordinates, with unknown geopotential, horizontal wind components, and vertical motion variable. The system is reduced by eliminating vertical velocity, discr…
This paper examines crystallization behavior in eutectic-type binary alloys subjected to cooling rates of about 10^5 degrees per second, focusing on whether highly supersaturated primary solid solutions form under such conditions. Using rapidly solidified thin films studied by metallography, X-ray s…
A statistical thermodynamic calculation is presented for the adsorption equilibrium of argon on the basal face of graphite at low surface coverage. The authors compute the single-particle partition function from a model potential energy surface obtained by summing dispersion and repulsion interactio…
This study examines how electron donor substituents in the meta position and alkylation of the NH group affect the absorption spectra of 4-nitrodiphenylamine derivatives. Using a chromophoric decomposition approach, the authors compare spectral maxima for substituted and N-alkylated compounds in eth…
This study examines the alkylation of 4-fluorophenol with propylene and cyclohexene using boron fluoride based catalysts, BF3, H3PO4 and BF3, O(C2H5)2, a reaction not previously described for fluorophenols. Experiments varied catalyst type and amount, temperature, and reactant ratios, and products w…
This paper reports a thermochemical determination of standard enthalpies of formation for perchloric acid and several perchlorates, motivated by limited existing data. The authors measure decomposition, dissolution, and neutralization enthalpies calorimetrically, then apply Hess’s law with selected …
This study examines excess metallic phases in heat-treated multicomponent nickel alloys of the Ni, Cr, W, Mo, Nb, Ti, Al system, with emphasis on compounds formed at different niobium contents. Using intermetallic analysis, anodic dissolution in methanol-based electrolytes, microchemical analysis, e…
