V. A. Kakichev
This paper studies boundary value problems of linear conjugation for functions holomorphic in bicylindrical domains, formulated on the product of two smooth closed contours with Hölder boundary data. Using Cauchy type integrals, singular operators, and reductions to elementary homogeneous and nonhom…
I. A. Kipriyanov, M. I. Klyuchantsev
The paper studies boundary value problems in a half-space for constant-coefficient B-elliptic differential equations involving the Bessel operator, with homogeneous boundary operators satisfying the Lopatinskii condition. Using the Fourier-Bessel transform, the problem is reduced to ordinary differe…
V. I. Burkov, V. A. Kizel', M. F. Kostenko, Z. B. Perekalina
This paper reports experimental studies of optical activity in the infrared region of vibrational transitions, a spectral range in which such effects had received little prior theoretical or experimental attention. The authors measured rotatory dispersion in three dithionate crystals, SrS2O6·4H2O, C…
L. M. Gluskin
This note studies simple positional operatives, including associative, alternative, and more general permutation-defined classes, and extends parts of the Rees, Sushkevich, Clifford theory of completely simple semigroups to these n-ary algebras. It develops structural results for i-simple, j-simple,…
L. R. Volevich, S. G. Gindikin
This note introduces a class of pseudodifferential operators whose symbols are analytic in one complex half-plane variable and satisfy conditions analogous to Petrovskii correctness, strong correctness, and constancy of strength. The authors develop a symbolic calculus for these operators modulo ope…
I. I. Ibragimov
This paper studies interpolation of functions analytic in the complex plane except for finitely many singularities by rational functions whose poles are prescribed at those singular points and whose interpolation nodes accumulate only at them. Using an integral representation of the interpolation re…
M. G. Dzhavadov
This note justifies an asymptotic method for a boundary value problem for the biharmonic equation arising in the pure cylindrical bending of a thin simply supported rectangular plate. After scaling the transverse variable by the small thickness parameter, the solution is constructed through an itera…
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This paper studies instability of equilibria in systems of ordinary differential equations subject to small, constantly acting perturbations. Using an auxiliary Lyapunov-type function whose derivative along the unperturbed system is nonnegative, the argument derives sufficient instability conditions…
K. M. Musaev
This paper studies boundary properties of generalized analytic functions satisfying a first order Vekua type equation with coefficients in an appropriate integrability class. Using estimates for the basic kernels, it extends classical results on Cauchy and Cauchy-Stieltjes integrals to this setting,…
N. H. Ibragimov
The paper determines the widest local Lie groups of point transformations admitted by homogeneous wave equations for zero mass fields, focusing on the Dirac, Maxwell, and weak gravitational field equations. Using the standard infinitesimal Lie method, it shows that the space-time part of the admitte…
Ya. B. Livchak
The paper develops an algebraic approach to limits in which every indexed sequence has a limit, defined as a coset modulo a chosen normal divisor, subspace, ideal, or lattice ideal. It distinguishes fine and rough limits, relates them to reduced products and infinitesimal sequences, and shows that s…
O. V. Bol'shakova, V. A. Troitskaya
This paper examines the global modulation of sustained geomagnetic Pc 2 to Pc 4 oscillations and its relationship to the orientation of the interplanetary magnetic field in the ecliptic plane. Using IMP I measurements from December 1 to 14, 1963, compared with continuous ground records of Pc activit…
V. S. Starunov
The paper develops a nonlinear theory of stimulated light scattering in the Stokes wing of the Rayleigh line, attributed to the orientation of anisotropic molecules in strong optical fields. It derives coupled Maxwell equations for laser, Stokes, and anti-Stokes waves, obtains exponential gain in th…
V. V. LARICHEVA, M. V. REIN
This paper studies the nonuniqueness of extremal solutions in optimal control problems governed by ordinary differential equations and Pontryagin’s maximum principle. It introduces the notion of the relief of a functional, a hypersurface describing the value of an extremal functional over a set of i…
S. Sirota
The paper studies Vietoris hyperspaces of closed subsets of bicompact spaces and their behavior under inverse spectra. It proves that the hyperspace functor commutes with inverse limits of spectra of bicompacta, using exponential continuations of bonding maps, and develops auxiliary results on d-map…
N. I. Vulfson, L. M. Levin
This paper examines whether developing cumulus clouds can be disrupted by artificially initiated downdrafts, using a theoretical model of spontaneous ascending and descending jets in an unstable atmospheric layer. Treating cumulus clouds as unstable layers with conical jets, the authors compare calc…
I. V. Pomerantseva, L. S. Shumilina
This paper reports results from the deployment of thirteen “Zemlya” seismic recording stations in Tashkent from June to December 1966, organized to investigate crustal structure and the causes of the April 1966 Tashkent earthquake. Using records of distant, nearby, and local earthquakes, together wi…
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This paper studies minimax properties of the usual squared multiple correlation test \(R^2\) for testing zero correlation in a multivariate normal sample, focusing on the case \(p=3\) with large sample size. Building on earlier work of Giri, Kiefer, Linnik, Prokhorov, and Shalaevskii, it proves that…
V. B. Zylev
The note studies finite decompositions of compact bodies in a topological space under the action of a group whose transformations can place any body inside any other. It defines notions of G-composability, equivalence by rearrangement of finitely many transformed pieces, and G-complementability, equ…
P. E. Krasnushkin, R. B. Baibulatov
The paper develops a computational method for determining angular wave numbers of normal waves in spherically layered anisotropic media by recalculating a matrix impedance operator. Starting from Maxwell’s equations, it derives a Riccati-type sweep equation for the impedance matrix and formulates th…
N. N. Bogolyubov (Jr.)
The paper relates Thirring’s quasispin model to a broader class of exactly solvable model Hamiltonians previously studied by the author using the method of approximating Hamiltonians. It shows that, with suitable choices of the collective spin operators and free part of the Hamiltonian, Thirring’s H…
V. A. Baranenko, Yu. M. Pochtman
This paper applies Bellman dynamic programming to nonlinear static problems for thin elastic rods formulated as minimization of potential energy. For a cantilever curved flexible rod under distributed moments and forces of varying magnitude and direction, the rod tangent angle is treated as the stat…
Yu. A. Volkov
The paper studies Cohn-Vossen’s problem of estimating changes in Euclidean distances on closed convex surfaces from changes in their intrinsic metrics. It proves that if two closed convex surfaces are related by a homeomorphism whose intrinsic distances differ by at most epsilon, then the correspond…
A. N. Sevchenko, A. A. Kovalev, V. A. Pilipovich, Yu. V. Razvin
This paper investigates the polarization of stimulated emission from glycerol and alcohol solutions of the organic dyes cryptocyanine and AlCl PhC under polarized ruby laser excitation. The authors combine experiments with a two-level molecular model to derive the angular dependence of the gain coef…
V. P. Gurarii
This paper studies primary ideals in the convolution Banach ring of functions on the positive half-line that are integrable with an increasing weight satisfying standard submultiplicativity and growth conditions. Using an approximation theorem for right translations, it describes the primary ideals …
I. S. Kats
This paper studies the high-energy growth of spectral functions for generalized second-order boundary-value problems with a boundary condition imposed at a regular endpoint. For a class of decreasing weight functions that includes powers with exponent between minus one and zero, it gives necessary a…
L. S. Frank
The paper studies numerical regularization of an ill-posed Cauchy problem arising as a model for the inverse problem of ideal gas flow in a Laval nozzle. It formulates the problem as the Cauchy problem for the Cauchy-Riemann equation in an angular domain and establishes conditional well-posedness un…
E. D. Lozanskiy
This paper examines the Townsend ionization coefficient in helium when indirect ionization by excited helium atoms is included, motivated by evidence that reactions involving the metastable or excited state He may supply electrons more effectively than direct electron impact under some conditions. T…
B. V. Deryagin, D. V. Fedoseev, V. M. Lukyanovich, B. V. Spitsyn, V. A. Ryabov, A. V. Lavrent'ev
This paper reports experiments on the growth of diamond whisker crystals from a carbon-containing gas at subatmospheric pressures on seed diamond single crystals, addressing the problem of graphite deposition that limits earlier diamond buildup methods. Using a radiation-heating apparatus, the autho…
M. I. Korsunskii, M. M. Sominskii, B. A. Zubarev
This paper examines the mechanism responsible for anomalously high photovoltage in CdTe films, a phenomenon previously interpreted mainly through a series of microscopic p-n junctions or through diffusion, Dember, processes. The authors argue that earlier criteria based on sign inversion with illumi…
A. I. Felzenbaum
This paper formulates a nonstationary hydrodynamic model for an inhomogeneous ocean, extending an earlier stationary treatment to include time-dependent adjustment of level, velocity, temperature, salinity, and density under wind stress, atmospheric pressure gradients, and surface heat and salt flux…
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The paper studies Chebyshev minimax problems for general interpolation classes of continuous functions, with emphasis on the convergence of generalized methods of successive Chebyshev interpolations. After recalling the interpolation, continuity, and alternation properties defining such classes, the…
M. G. Gasymov
The paper studies eigenfunction expansions for a non-self-adjoint three-dimensional Schrödinger operator with a complex exponentially decreasing potential. Using solutions of the associated scattering problem, it analyzes solvability and analytic continuation of the Lippmann-Schwinger type integral …
S. D. Volkov, V. P. Stavrov, V. Ya. Dolgikh, V. M. Mendelson
A statistical boundary-value problem in thermoelasticity is formulated for a macroscopically homogeneous, quasi-isotropic two-component medium with isotropic constituents and random component distribution described by moment functions. For uniform cooling in the absence of external forces, the autho…
B. T. Geilikman, V. Z. Kresin
This paper examines electromagnetic properties of superconductors with strong electron phonon coupling, motivated by materials such as lead, mercury, gallium, niobium nitride, and bismuth films for which weak coupling theory is insufficient. Using thermodynamic Green functions in a magnetic field an…
B. A. Maksimov, V. V. Ilyukhin, N. V. Belov
The paper reports an X-ray crystallographic determination of a hydrothermally synthesized potassium yttrium silicate obtained from the system K2O, Y2O3, SiO2, H2O, initially without a known chemical formula. Weissenberg and diffractometer data were analyzed through Patterson methods, symmetry testin…
V. S. Gerasimenko, B. Ya. Lubov
This paper develops a theoretical description of nonstationary crystal growth from a melt under nonisothermal conditions, combining heat removal through the growing solid with the physicokinetics of two-dimensional nucleation at the crystallization front. Starting from the Becker-Döring and Zel’dovi…
LIVIU LIBRESCU (L. LIBRESCU)
This paper develops a bending theory for symmetric anisotropic three-layer elastic plates whose outer layers have identical properties and whose core may be either stiff or light. Using curvilinear coordinates, Love-Kirchhoff assumptions for the face layers, moderate-thickness plate theory for the c…
G. V. Chudnovskii
The paper studies model-theoretic properties of infinitary languages \(L_{\alpha\beta}\), focusing on compactness for restricted classes of axioms, preservation theorems, and characterizations of axiomatizable classes. It proves universal compactness under a cardinality condition on the signature, d…
B. V. Kuksenko, S. A. Losev
This paper examines vibrational excitation and relaxation of diatomic molecules in atom, molecule collisions, using classical trajectory calculations for oxygen, argon interactions with varied intermolecular potentials, molecular orientations, impact parameters, relative energies, and initial rotati…
A. I. Guseinov, G. A. Rasulova
This paper studies a mixed initial boundary value problem on a finite interval for a third order quasilinear differential equation with a dissipative mixed derivative term and homogeneous Dirichlet boundary conditions. Using Fourier sine expansions, Banach spaces adapted to the boundary conditions, …
A. Kh. Mirzadzhanzade, A. K. Karaev, A. A. Movsumov, U. D. Mamadzhanov, G. T. Gasanov, R. T. Aliev
This paper examines hydraulic resistance during the flow of clay solutions in pipes with permeable walls, a condition relevant to borehole annular spaces and not covered by earlier studies of impermeable pipes. The authors discuss why changes in total flow rate and in structural mechanical propertie…
A. G. Ramm
The paper studies the asymptotic distribution of eigenvalues for the three-dimensional Schrödinger operator with a continuous potential tending to infinity in unbounded domains whose boundaries may be infinite. It defines a class of admissible domains and proves discreteness and an approximation res…
A. V. Pogorelov
This note examines postcritical elastic equilibrium of a closed spherical shell under external pressure, restricting attention to axisymmetric deformations after loss of stability. Using a variational principle for isometric transformations of the shell middle surface, the deformation is represented…
1. Consider the system of ordinary differential equations
The paper studies bifurcation and Lyapunov stability of small nonzero periodic solutions in parameter-dependent systems of ordinary differential equations whose linearized monodromy matrix has the eigenvalue one with multidimensional degeneracy. Using generalized eigenvectors, adjoint vectors, and a…
A. P. Vinogradov, Yu. A. Surkov, K. P. Florenskii, B. M. Andreichikov
This paper reports preliminary direct measurements of the chemical composition of the atmosphere of Venus obtained during the Venera 4 descent. Using physicochemical gas analyzers operated at two atmospheric levels, the study estimates an atmosphere dominated by carbon dioxide, about 90 percent with…
A. B. Vasil'eva, V. A. Tupchiev
This paper studies periodic solutions of two-dimensional autonomous differential systems in which a small parameter multiplies the derivatives, focusing on trajectories inside a saddle separatrix cell that approach the separatrix cycle as the parameter tends to zero. Under smoothness and nondegenera…
Academician of the Academy of Sciences of the Uzbek SSR T. A. SARYMSAKOV, Ya. Kh. KUCHAROV
This paper studies the law of the iterated logarithm for sums of independent random variables represented as measurable elements of a complete topological semifield equipped with a Boolean algebra and measure. After formulating integration, probability, independence, and Laplace transforms in this s…
A. V. Pogorelov
The paper studies a variational problem for regular parametrized surfaces with prescribed spherical image and prescribed boundary support function, where the integrand is a positive, first-degree homogeneous, strictly convex function of the oriented area element. It reformulates the problem using th…
Yu. I. Yalamov, I. N. Ivchenko, B. V. Deryagin
This paper calculates the diffusion-slip velocity of a binary gas mixture near a solid plane wall when a tangential concentration gradient is present. Unlike earlier treatments that assumed incident molecular distributions in the Knudsen layer remain equal to bulk distributions, the authors solve li…