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 examines the use of a diffraction grating interferometer for quantitative investigation of gas flows around models in a shock tube, where simultaneous visualization of shock structures and density measurements is required under vibration and transient conditions. The authors analyze pract…
The paper studies one-dimensional multiphase Stefan-type problems with several moving internal and external fronts governed by nonlinear parabolic equations and front conditions. It applies a front-straightening change of variables that maps each moving phase interval to a fixed strip, then uses suc…
This note studies metrizability questions for finally compact and related topological spaces with point-countable bases. Its main theorem proves that a finally compact p-space with a point-countable base must have a countable base and is therefore metrizable, using perfect mappings onto second-count…
The paper studies a discontinuous linear conjugation boundary value problem for analytic functions in Hardy classes on a closed Riemann surface with Lyapunov contours and measurable data. It develops an analogue of Schwarz’s alternating method to prove a harmonic extension theorem, then applies it t…
This note develops properties of constructive generalized functions, continuing the author’s earlier definition of a constructive analogue of classical distributions. It introduces equality on intervals, carriers and bounded carriers, limits of sequences and parameter-dependent families, linear chan…
This paper studies solvability of first and second order Cauchy problems for abstract parabolic equations in a Banach space with time dependent, generally unbounded operators whose domains may vary with time. Under resolvent estimates and Hölder type continuity assumptions on the operator coefficien…
This paper studies non-self-intersecting curvilinear rays on closed surfaces, understood through their lifts to the universal covering surface. It proves that any such lifted ray which goes to infinity has an asymptotic direction, treating orientable surfaces of negative Euler characteristic via the…
This paper addresses the experimental study of the transition from linear to nonlinear behavior in parametric resonance for systems approximated by Hill-type equations with periodic coefficients. Using Floquet theory, it derives a relation among three values of a solution separated by one period, al…
This paper extends earlier results on second order elliptic equations that degenerate on a closed subset of the boundary to bounded domains with arbitrary smooth boundary. It formulates Dirichlet and oblique derivative boundary value problems in which the ellipticity may fail on separated boundary p…
The problem of approximating, on a finite time interval, the solutions $x(t)$ of an $n$-dimensional system of linear differential equations \begin{equation} dx(t)/dt=\sum_{i=1}^n A_i(t)x_i(t-h_i(t)) \label{1} \end{equation} with variable delays $0\le h_i(t)\le h$ is considered. It is shown that the …
This paper develops an operational approach for obtaining integral characteristics of nonstationary diffusion or heat transport in active, possibly multilayer media without explicitly inverting Laplace transforms. It considers processes with linear conversion or source terms and shows that quantitie…
This paper extends Korovkin-type convergence theorems for sequences of linear positive operators by replacing uniform convergence with convergence in the Hausdorff distance between completed graphs of functions. It introduces the notion of local monotonicity through a modulus of nonmonotonicity and …
The paper calculates the phonon frequency spectrum of the silicon lattice and uses it to derive principal thermodynamic functions. Starting from Born and von Karman lattice dynamics for the diamond structure, the authors use experimentally determined elastic constants and Raman frequency data at 73 …
The paper reports an X-ray crystallographic determination of the triclinic structure of potassium bichromate, K2Cr2O7, lopezite, using single-crystal diffraction data and three-dimensional Patterson and electron-density syntheses. The structure is refined in the centrosymmetric space group P1bar, wi…
This note extends aspects of Jordan theory to a class of bounded linear operators in separable Hilbert space whose spectrum is concentrated at zero, whose imaginary part is nonnegative, and whose imaginary component has finite trace. Using Brodskii’s notion of a single-block operator and a quasidire…
This note studies a one-dimensional analogue of a second-order elliptic equation whose leading coefficient vanishes at the boundary, focusing on smoothness of bounded solutions up to the degeneracy point. The equation is reduced to Volterra integral equations, and properties of the associated integr…
This paper analyzes a nonlinear magnetohydrodynamic effect in which a self-sustaining high-temperature, electrically conducting gas layer forms through preferential Joule heating during nonstationary interaction of a compressible conducting medium with a magnetic field. The authors examine the pheno…
This paper examines the conversion of electrical energy into mechanical work during an electric discharge in a gas or plasma channel. Using the first law of thermodynamics and the ideal gas equation, the authors derive expressions for the mechanical energy produced by expansion, the load giving maxi…
This paper examines variations in radon content in deep thermomineral waters of the Tashkent basin as a possible precursor to strong tectonic earthquakes, using observations made before and after the 26 April 1966 Tashkent earthquake. The authors relate a long-term rise, rapid increase, subsequent s…
The paper develops a realization of infinite-dimensional representations of the rotation group, or equivalently SU(2) locally, with arbitrary complex weight in spaces of single-valued entire functions, avoiding earlier realizations by multivalued analytic functions with branch singularities. Startin…
The content of the article is determined by the decisive role of a special exponent in the study of solutions to differential equations. The main result is contained in Theorem 1: If the operator $A(t)$ in equation \begin{equation} \frac{dx}{dt}=A(t)x\tag{1} \label{1} \end{equation} is such that for…
The paper addresses a problem posed by A. A. Markov: to find an effective criterion for when a method of translating alphabets preserves the translation theorem for normal algorithms. It defines admissibility for such translation methods and proves that admissibility is equivalent to nondegeneracy t…
The paper examines the anomalously strong lithium absorption observed in T Tauri type stars and its possible relation to nonthermal processes in stellar atmospheres and to lithium in cosmic rays. Using a photoionization and recombination balance for neutral and singly ionized lithium, and adopting a…
This paper considers dynamic synthesis of a mechanical system with a variator, seeking laws of variation of the transmission ratio that realize prescribed motion of either the driving or driven link. Starting from differential equations of motion in relative variables, it derives finite solutions fo…
This paper studies an elliptic boundary value problem in a bounded three-dimensional domain with an oblique derivative condition that degenerates along a finite set of boundary curves where the oblique field becomes tangent. The boundary curves are classified by the direction of the field on their t…
Methods are proposed for constructing the right-hand sides of a system of differential equations for the gradient method, ensuring acceleration of the convergence process. In this context, the system of differential equations describing the motion of a phase space point toward an extremal point is c…
Linearly independent systems \begin{equation} \{\ln r(x_i,y)\},\quad\biggl\{\frac{\partial}{\partial n_y}\ln r(x_i,y)\biggr\}\quad(i=1,2,\dots), \label{1} \end{equation} are considered, where $x_i$ are uniformly distributed on the circle $S_1$, and $y \in S$; here, $S$ and $S_1$ are concentric circl…
This paper reports measurements of reflection and scattering of meter wavelength radio waves from the lunar surface using signals emitted by the Luna 11 satellite and received on Earth. By separating direct and reflected components through their differing Doppler shifts, the authors determined the v…
This paper studies existence and uniqueness for nonlinear Hammerstein integral equations with symmetric matrix kernels in general ideal Banach spaces of vector functions. The authors reduce solvability questions to properties of the associated linear integral operator and the superposition operator,…
The paper studies boundedness criteria for Nemytskii operators and applies them to Sobolev’s problem of characterizing coefficient functions satisfying a condition called T-invariance for quasilinear hyperbolic equations. It first proves that a Carathéodory function A(x,y) defines a bounded operator…
This paper derives particular exact solutions for axisymmetric, nonstationary motions of a rarefied plasma with anisotropic pressure, magnetic field, and self-gravitation, under the assumption that the magnetic field is perpendicular to particle trajectories. Using a self-similar radial velocity pro…
The paper analyzes the flow produced by a plane, cylindrical, or spherical point explosion in a perfect gas capable of detonating, treating the shock and reaction zone as a single strong discontinuity with heat release. It argues that the early motion is close to the classical point explosion while …
This note studies topological invariants of noncompact Lie groups that become visible when principal bundles are allowed to have Hausdorff, possibly nonparacompact, bases, rather than only CW-complex bases. It constructs universal spaces for such bundles and proves that natural assignments from prin…
This paper examines whether electromagnetic sounding methods can distinguish internal geoelectric divisions within the crystalline basement. Field measurements from the Priozersk district were combined across a wide frequency range, using several sounding configurations and magnetotelluric data tran…
This paper develops a numerical formulation for nonlinear problems of baroclinic ocean circulation, extending earlier linearized pressure based models. The governing equations for velocity, pressure, and density are posed with surface, bottom, lateral boundary, and initial conditions, then treated b…
This paper analyzes turbulent exchange in the lower atmosphere over oceans, emphasizing effects of water vapor on buoyancy, entropy flux, and long wave radiative heat transfer. It formulates stationary boundary layer equations for momentum, moisture, heat, and turbulent energy, incorporating latent …
A regular solution of the equation \begin{equation} L_nL_{n-1}\dotsb L_1u=0, \label{1} \end{equation} is considered, where $$L_i=A_i\frac{\partial^2}{\partial x^2}+2B_i\frac{\partial^2}{\partial x\partial y}+C_i\frac{\partial^2}{\partial y^2}+D_i\frac{\partial}{\partial x}+E_i\frac{\partial}{\partia…
This paper analyzes the propagation and generation of magnetohydrodynamic waves in the Earth’s magnetosphere as a possible explanation for geomagnetic micropulsations. Using curvilinear coordinates tied to an axially symmetric magnetic field, the authors derive wave equations for Alfvén and magnetoa…
This paper studies cluster decomposition properties for vacuum expectation values of radiation operators and for matrix elements of the causal S-matrix in Bogolyubov’s axiomatic framework, restricted for simplicity to a real scalar field with self-interaction. Using the causality condition, complete…
This paper investigates emission currents and photoelectric properties in sandwich diode structures fabricated from high-resistance polycrystalline gallium arsenide films on insulating quartz substrates. The authors prepared aluminum, gallium arsenide, aluminum structures by vacuum evaporation and a…
The paper studies Dirichlet problems for second order elliptic systems written in complex form, focusing on cases where the standard problem is not Noetherian unless suitable terms involving the conjugate unknown are present. It derives integral representations of solutions through holomorphic funct…
This paper develops a simplified linear model for long-term ocean atmosphere interaction, treating nonadiabatic atmospheric processes through a quasigeostrophic potential vorticity equation coupled to heat exchange at the ocean surface. The model incorporates radiative and condensation heating, turb…
