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 studies the Green matrix for homogeneous parabolic boundary value problems for systems whose coefficients may be discontinuous across a smooth interior hypersurface. The authors formulate the transmission problem, relate the constant coefficient model problem in the whole space to a stand…
This paper studies stability in probability for automatic control systems with variable structure whose dynamics include a random perturbation term. Using a positive definite quadratic form as a Lyapunov-type function and interpreting solutions of the discontinuous deterministic system in the sense …
This paper studies estimates for neighboring coefficients of normalized univalent functions in the unit disk, focusing on bounds for the difference between the moduli of consecutive coefficients. Using coefficient systems associated with meromorphic univalent functions outside the unit disk and a le…
Transient photocurrent processes in cadmium telluride films exhibiting the anomalous photovoltaic effect are investigated in order to determine the intrinsic photocurrent relaxation time apart from circuit RC limitations. Using intense pulsed optical excitation with submicrosecond fronts and a low-c…
This paper develops a theoretical framework for representing large-scale meteorological fields by biorthogonal eigenfunction expansions derived from the linearized hydrothermodynamic equations about a prescribed climatic state. The author formulates the basic and adjoint operators in a three-dimensi…
This note addresses a gap in earlier results on rings of quotients, namely that the system of elements denoted S1(S2) in R(S2) need not be multiplicatively closed. It introduces maximality of a multiplicatively closed system relative to an almost S-prime ideal and proves a characterization: such max…
The paper develops a metric theory for linear systems of ordinary differential equations with bounded uniformly continuous coefficients, motivated by variational equations along families of trajectories in dynamical systems rather than along a single trajectory. It studies the shift dynamical system…
This paper analyzes 148 three-prong inelastic interactions of 19.8 GeV/c protons with quasi-free neutrons in Ilford G-5 nuclear emulsions, focusing on secondary proton angular and momentum characteristics in the nucleon center-of-mass system. The proton angular distribution is strongly collimated al…
This paper examines current oscillations in homogeneous CdS crystals under conditions where their conductivity is below the critical value normally required for spontaneous current pulsations. Using a CdS sample in the current saturation regime, the authors introduced a high intensity 25 MHz ultraso…
The paper studies the Cauchy problem and a mixed boundary value problem for a second order parabolic system modeling heat and substance transfer, with boundary conditions not involving time derivatives. Using the contour integral method, it constructs a fundamental matrix of solutions in closed form…
The paper studies the construction of proper guiding functions for planar systems of ordinary differential equations whose leading terms are homogeneous vector fields and whose remaining terms are asymptotically smaller. Using the rotation index of the homogeneous field and an angular quasi-monotoni…
The note studies resolvents of generalized self-adjoint extensions of symmetric operators within a rigged Hilbert space framework \(G_{+}\subseteq G_{0}\subseteq G_{-}\). It first characterizes eigenvalues of a generalized self-adjoint operator by non-density of the corresponding range and derives d…
This paper investigates supersonic unsteady flow past blunt bodies of revolution undergoing small plane angular oscillations. Using a linear expansion in oscillation amplitude, the steady flow and the disturbance fields in phase with angle of attack and angular velocity are computed numerically in s…
This paper proposes a branch-and-bound enumeration method for the multidimensional 0-1 knapsack problem, using information from the linear programming relaxation to improve upper bounds and reduce the search. The method defines records for feasible partial solutions, transition rules for enumeration…
This paper studies quadratic variational control problems in real Hilbert spaces in which the cost includes both control effort and deviation from prescribed terminal or trajectory data. A general existence and uniqueness theorem is formulated for bounded linear operators, reducing the minimization …
This paper studies bounded and structurally constrained solutions of the linear differential equation x dot plus Ax equals phi in a complex Banach space, where A is a bounded operator whose spectrum does not meet the imaginary axis. It introduces a general class of function spaces defined by a trans…
This note studies extremal quasiconformal homeomorphisms between closed Riemann surfaces of genus greater than one under additional constraints: prescribed homotopy class, conformality on specified subdomains, and prescribed values or jets at finitely many points. It generalizes Teichmüller’s extrem…
Elastic scattering of fast ground state oxygen and nitrogen atom beams by NO and CO molecules is studied to probe short range interaction potentials and possible electronic transitions during collisions. Cross section dependences on beam energy are measured and used to determine parameters of effect…
This paper examines how mechanical vibrations of brushes affect commutation in commutator electrical machines through modulation of brush to commutator contact resistance and voltage drop. Tangential and radial vibrations are treated separately, with analytical expressions for time varying transitio…
The paper analyzes multipole pulsed-power synchronous generators as both kinetic energy storage devices and short-duration energy sources. Using expressions for emf, subtransient reactance, leakage permeance, damping constants, and rotor kinetic energy density, it argues that pulsed power can be inc…
This paper addresses the effect of manufacturing and operational deviations on commutation reliability in direct current machines, arguing that tolerance assignment should be probabilistic rather than based on maximum and minimum deviations. It develops an analytical model linking nominal electromag…
This paper addresses the mismatch between the rated power of induction motors used on universal metal-cutting machine tools and their typically low average operating loads. Drawing on prior load measurements described by a Weibull distribution, it argues for a motor modification with increased overl…
The paper addresses the mismatch between the low average loading of induction motors on universal metal-cutting machine tools and the high rated power selected to satisfy pull-out torque requirements. Using previously established Weibull load-distribution data for 1K62 machine tools, the authors arg…
This paper analyzes the energy balance of the transient process that occurs when the field winding of an impulse generator is connected to a constant voltage, with particular attention to losses in rotor windings. Using a simplified coupled circuit model for the excitation and damper windings, the a…
The paper examines static and dynamic current-voltage characteristics of sliding brush contacts in commutator electric machines, emphasizing the role of the cuprous-oxide surface film as a semiconductor blocking layer. It argues that static equivalent circuits using only ohmic resistances are insuff…
The paper addresses calculation of the leakage field of main poles in the commutation zone of P-series DC machines, a factor important for commutation stability especially under deep speed regulation and magnetic saturation. It proposes an empirical method based on conductive-paper field modeling an…
This paper analyzes the voltage spectrum of a single-phase inverter using sinusoidal pulse-width modulation, with attention to unipolar modulation as a means of reducing harmonic amplitudes and load-current ripple. An engineering-oriented method is developed for trailing-edge one-sided modulation by…
This paper examines how effectively active materials are used in combined electrical machines whose windings share common slots in a magnetic core. It develops a general analytical formulation for machines combined in a common active volume, introducing distribution coefficients for electric and mag…
This paper analyzes the operating stability of a brushless DC electric machine amplifier under active, active-inductive, and motor load conditions. Differential equation systems are formulated for each load case, reduced to characteristic equations of second, third, or fourth order, and stability re…
This paper presents a method for artificially modeling commutator surface profiles in order to study how commutator condition affects brush contact behavior in commutator machines. The authors argue that mechanical machining cannot accurately reproduce the small interbar steps typical of real commut…
This paper addresses objective assessment of commutation in direct current machines, focusing on limitations of photoelectric sparking observation and earlier instruments that measured only integral voltage pulses under the brush trailing edge. It argues that commutation stability can be evaluated f…
The paper develops a methodology for evaluating how operating conditions affect the economic efficiency of electrical machines. It considers annual operating hours, load and no-load time, load factor, energy tariffs, environmental severity, reliability requirements, and overload capacity, showing ho…
This paper examines how to evaluate the economic efficiency of new electric machine designs, using commutator and brushless electric-machine amplifiers as examples. It outlines a procedure for estimating cost and price from aggregate data, bringing technical and economic indicators into comparable f…
This paper examines how mechanical conditions in the commutator and brush assembly affect the actual time during which a commutator segment is short-circuited by a brush, distinguishing it from the apparent contact time. The authors combine analytical expressions with oscillographic measurements on …
This paper investigates tangential self-excited vibrations of brushes in sliding electrical contacts, a problem linked to disturbances in commutation but less studied than radial brush vibrations. Using the theory of frictional vibrations, the authors develop a mechanical model of the brush, derive …
This paper analyzes the mechanical stability of electric brush operation on commutators and slip rings, focusing on brush lift-off caused by eccentricity, ellipticity, surface harmonics, and interlamellar height differences. It develops analytical models for brush response to harmonic and impact dis…
This paper addresses the development of contactless sensors for measuring commutator profiles of operating electrical machines, where high voltage, sparking, small gaps, and narrow lamellae complicate dynamic measurement. The authors analyze transformer-type eddy-current sensors with shielded ferrit…
This paper develops a no-load theory for a proposed brushless DC electric-machine amplifier, a two-stage single-armature device using semiconductor commutators. Assuming an unsaturated magnetic circuit and a constant commutation-axis displacement, the authors formulate differential equations in term…
The paper analyzes how the steady-state current in the control winding of a regulated-frequency brushless electric-machine amplifier with a thyristor controlled commutator depends on the repetition frequency of control pulses. Using a staged commutation model, the authors derive expressions for the …
This paper proposes a three-stage brushless electric-machine amplifier of regulated frequency in which an asynchronous generator is connected in parallel with the first stage to reduce the counter-emf induced in the control winding under active-inductive loading. It derives frequency relations, ener…
This paper examines a cascade brushless synchronous motor intended to address limitations of existing low-power brushless synchronous designs, including large size, low starting torque, and reliability issues associated with rotating rectifiers. The proposed motor combines two asynchronous machines …
This paper examines the design of a contactless alternating-current electric-machine amplifier in which generator stages are combined in a single magnetic core to reduce size and weight. It derives relationships for distributing electromagnetic loadings between cascades, including constraints on mag…
This paper analyzes the initial voltage dip in a contactless AC electromechanical amplifier with phase compounding when an inductive load, representing the starting condition of an asynchronous motor, is switched on. The authors derive transient equations for the amplifier without feedback at the fi…
This paper develops a transient theory for a brushless AC electromechanical amplifier consisting of an inverted synchronous generator and an asynchronous frequency converter in a common magnetic core. Using Park, Gorev idealization, symmetry assumptions, and transformations from three-phase variable…
This paper develops an analytical method for studying commutation in a transverse-field electric-machine amplifier using dynamic, rather than averaged static, current-voltage characteristics of the brush and commutator contact. It derives separate empirical approximations for cathode- and anode-pola…
This paper examines the electrical behavior of the brush and commutator segment sliding contact in electric machines, with particular attention to capacitance in the contact layer and its role in commutation. It develops a physical model representing the contact as a nonlinear parallel combination o…
This article addresses the design of cross-field electric-machine amplifiers with a smooth armature, for which conventional machine-constant methods do not give voltage-independent sizing curves. It argues that such amplifiers require a single-layer armature winding, limited air-gap induction, and h…
This paper develops and tests a mathematical model of a transverse-field electric-machine amplifier with a smooth armature, emphasizing internal feedbacks and nonlinear effects that are often neglected in simplified representations. A nonlinear system of differential equations is formulated for oper…
This paper investigates voltage pulsations, vibration, and noise in production transverse-field electric-machine amplifiers and compares them with amplifiers using a smooth armature. By relating calculated excitation frequencies to measured spectra of output-voltage pulsations, vibration, and acoust…
