Translated papers from the Chinese Preprint site, Chinaxiv
Showing 50 of 15540 papers
Generated abstract This paper studies the topological classification of normally solvable boundary value problems for Petrovskii elliptic systems in a simply connected planar domain. Using the invariant subspace associated with the upper half-plane spectrum of the principal symbol, the authors express normal solvabili…
Generated abstract This paper examines possible secular changes in gravity across Ukraine using repeated gravity measurements made in 1962 and 1969 at 36 uniformly distributed points. Differences relative to a reference point in Kiev ranged from about +0.4 to −0.5 mGal, with estimated errors of approximately ±0.08 mGa…
Generated abstract This paper develops a four-terminal network representation for an optocoupler with direct optical coupling, specifically an injection light-emitting diode coupled to a photoresistor. It derives the conductance, impedance, and hybrid parameter matrices in terms of differential device characteristics,…
Generated abstract This note addresses a problem posed by Maskit concerning the existence of fundamental domains for finitely generated Kleinian groups. It reviews the relevant notions of regular and limit sets, forms the quotient of the regular set by the group, and analyzes its components as Riemann surfaces covered…
Generated abstract The paper studies stability of abstract three-level operator difference schemes in a Hilbert space, extending earlier stability results expressed in compound norms to estimates in standard energy norms associated with the scheme operators. Under positivity, Lipschitz continuity in time, and the cond…
Generated abstract The paper introduces condition R for varieties of universal algebras, a strengthening of the embedding theorem for partial algebras, and studies its consequences for free extensions, free closures, and free products. Under this condition, it proves analogues of the Nielsen-Schreier, Kurosh, and Grus…
Generated abstract This note studies the rate of uniform approximation of continuous periodic functions by partial sums of their Fourier series, using best trigonometric approximation and quantities measuring the tails of Fourier coefficients or remainders in related \(L_q\) metrics. It proves an estimate for \(\|f-S_…
Generated abstract The paper studies periodic convolution equations arising in mixed problems of elasticity, especially contact problems for finite bodies, in cases where the interval length is not assumed small relative to the period. For kernels with Fourier coefficients of order inverse linear decay, it establishes…
Generated abstract This paper studies elliptic boundary value problems for systems of linear differential equations in a smooth bounded domain when the boundary condition degenerates on a smooth codimension one submanifold of the boundary. The authors introduce weighted Sobolev-type spaces adapted to the degeneracy an…
Generated abstract This paper examines satellite thermal sounding of the atmosphere, in which vertical temperature profiles are inferred from measurements of outgoing thermal radiation. Using Nimbus III interference spectrometer data for Brownsville, Texas, the authors compare two inversion approaches for the resultin…
Generated abstract This note studies uniform convergence criteria for Fourier series of Bohr almost periodic functions whose Fourier exponents have a single limit point, considering separately the cases where the exponents tend to infinity or to zero. The criteria are formulated through rates of decrease of best appro…
Generated abstract The paper develops a method for solving differential equations whose variable coefficients include delta functions and their derivatives, motivated by models combining continuous structures with discrete concentrated elements. It first formulates a class of partially degenerate operator equations, t…
Generated abstract This paper examines the nucleon composition and excitation energies of nuclei undergoing photofission when bismuth-209, lead-208, and gold-197 targets are irradiated with photons of maximum energy 1 GeV. The authors derive fissioning-nucleus parameters from measured fragment kinetic energies and mas…
Generated abstract The paper studies integral relations for the Milne problem in radiative transfer in a half-space, including both the homogeneous case and the case with prescribed boundary insolation. It formulates the problem in an operator setting on functions over the unit sphere, recalls the associated character…
Generated abstract The paper examines absorption of intense laser radiation by an electron gas through the multiphoton Compton effect, a mechanism expected to become important when electron oscillation energy in the laser field is relativistic. Using results for Compton scattering in an external circularly polarized p…
Generated abstract This paper studies a global computational approach to regularization for evolution problems governed by positive definite self-adjoint differential operators, contrasting it with local time-stepping methods. The authors discretize the full space-time problem at once, reduce it to a system of linear …
Generated abstract The paper develops a continual integral representation for the fundamental solution of a broad class of parabolic type differential equations, motivated by limitations of earlier measure based generalizations of Wiener and Feynman formulas. For equations with polynomial symbol \(P(x,\xi)\) of even o…
Generated abstract This paper analyzes the motion of test masses on circular equatorial orbits in the gravitational field of a rotating body, interpreting the resulting asymmetry between co-rotating and counter-rotating motion as a gravitational analogue of the Zeeman effect or partial dragging of local inertial frame…
Generated abstract The paper characterizes relatively projective closed ideals in Banach algebras of continuous functions on a compact space. It proves that a closed ideal in C(Omega) is projective as a C(Omega)-module precisely when its spectrum, the corresponding open subset of Omega, is paracompact. The sufficiency…
Generated abstract This note extends parts of the theory of strongly continuous operator semigroups to semigroups that are strongly continuous only for positive time and may have a singularity at zero, provided the singularity is summable after multiplication by a power of time. It defines classes of semigroups \(L^{(…
Generated abstract The paper examines whether induced amplification of characteristic X-ray radiation can be achieved by producing an inverted population of inner atomic shells under X-ray pumping. It argues that, for certain inner-shell transitions and at densities close to those of solids, radiationless vacancy tran…
Generated abstract This note studies a boundary value problem with a large complex parameter for a second order elliptic system in a three-dimensional domain, motivated by contour integral methods for parabolic mixed problems with time derivatives in the boundary condition. Under spectral, smoothness, and boundedness …
Generated abstract This paper examines how nonuniform stiffness in elastic ring supports can induce parametric oscillations in a rigid rotor mounted on one elastic and one hinged support. The authors formulate linear equations for small forced oscillations including gyroscopic effects, viscous damping, rotor unbalance…
Generated abstract This paper examines whether coagulation charging of precipitation particles by ion-charged cloud droplets can account for electric fields required for thunderstorm development. Using earlier ion-balance calculations and field estimates, it argues that natural ionization rates yield precipitation-par…
Generated abstract This paper studies feedback control laws that maximize the domain of asymptotic stability for systems whose uncontrolled plant may be unstable. It defines stability optimality as inclusion maximality of the attraction domain and proves, under broad admissibility assumptions, the existence of an admi…
Generated abstract This paper studies a quasilinear system arising in a model of groove oscillations of a rarefied plasma cylinder in a strong external magnetic field. The system couples two transport equations for particle density distributions with a Poisson equation for the electric potential, with the initial data…
Generated abstract This paper investigates whether bismuth films condensed at liquid helium temperature, previously known to form a superconducting amorphous phase, exhibit a critical thickness beyond which this metastable phase disappears. High purity bismuth was evaporated in high vacuum onto glass substrates cooled…
Generated abstract This paper experimentally examines the spatial intensity distribution of stimulated radiation from a ruby traveling-medium laser with a small circular diaphragm placed inside a plane-parallel resonator. Near-field patterns at the resonator mirror and far-field patterns in the focal plane were record…
Generated abstract The paper studies boundary behavior of multidimensional quasiconformal and related monotone Sobolev mappings using the notion of Bessel capacity of type (1,n). It proves that for a monotone mapping of a ball belonging to the class W_n^1, angular boundary values exist at all boundary points except fo…
Generated abstract This paper presents a numerical study of the onset and structure of natural convection in water near its temperature of maximum density, where density depends quadratically on temperature rather than linearly. A two-dimensional stationary problem is solved for a viscous liquid in a square cavity hea…
Generated abstract This paper develops and applies a surface ionization method for determining electron affinity energies of atoms whose vapors contain atoms and molecules with temperature-dependent dissociation, a case not suited to earlier comparison techniques. The method compares mass-spectrometrically measured cu…
Generated abstract The paper introduces a family of function spaces defined through the variation of local polynomial approximation errors on cubes. It develops distribution estimates, embedding results, and a decomposition theorem showing that functions in these spaces can, outside sets of small measure, be represent…
Generated abstract This note extends Carleman’s quasianalyticity criterion to linear operators in Banach spaces, asking when bounds on iterates of an operator imply that the vector is zero. For operators without spectrum, the argument relates quasianalyticity of the sequence of bounds to the growth of the entire resol…
Generated abstract This paper studies bifurcation of small eigenfunctions for nonlinear operator equations in a real Banach space when the eigenspace corresponding to an isolated Fredholm spectral point has arbitrary finite dimension. It justifies reducing the problem by projection to a finite-dimensional homogeneous …
Generated abstract The paper studies exterior boundary-value problems for the polyharmonic equation in unbounded domains of Euclidean space whose complements are bounded. It formulates families of problems with standard Dirichlet-type boundary data on a simple boundary, distinguished by prescribed asymptotic behavior …
Generated abstract This paper examines whether crystalline long-range order can exist in one- and two-dimensional classical many-particle systems with pair interactions at nonzero temperature. Using Bogolyubov’s quasi-average method and a classical analogue of Bogolyubov’s inequality, the argument relates a possible n…
Generated abstract This paper applies the principle of maximum stability to determine the mean velocity profile in the viscous sublayer and buffer region of turbulent channel flow. Using a generalized Van Driest mixing-length formula with adjustable parameters, the authors analyze local hydrodynamic stability of short…
Generated abstract This paper studies ergodic limiting behavior in multichannel loss service systems governed by stationary sequences of interarrival and service times, using occupancy processes that record residual numbers in service after future time shifts. It proves convergence, in a strong coupling sense, to stat…
Generated abstract The paper studies the stability of time-periodic forced motions of a viscous incompressible fluid in a bounded three-dimensional domain, formulated through perturbations of a periodic Navier-Stokes solution in an energy space. It establishes well-posedness and compact differentiability properties fo…
Generated abstract The paper examines how electron thermal conductivity affects the propagation of laser radiation absorption waves in vapor formed above a strongly heated solid surface. A one-dimensional gas-dynamic model with radiation absorption and heat conduction is solved numerically, and a traveling-wave formul…
Generated abstract This paper reports measurements of low-frequency current oscillations in amorphous fused films of beta-carotene and in beta-carotene films containing protoporphyrin, using surface-type cells with tin electrodes under dark and illuminated conditions at room temperature. Oscillations appeared only in …
Generated abstract This paper derives an analytic expression for the flux of singly scattered neutrons emitted by an isotropic monoenergetic point source in a homogeneous infinite elastically scattering medium. Using the fundamental solution of the transport operator, the authors separate the uncollided and once-colli…
Generated abstract This paper investigates whether internal shock waves can occur in axisymmetric supersonic flow of a perfect gas past cones with spherical blunt noses and no break in the generatrix at the junction. Using finite difference calculations of the steady flow near a sphere, subsequent supersonic flow comp…
Generated abstract The paper derives a priori estimates and sufficient conditions for stability with respect to the right-hand side for three-level operator difference schemes in a Hilbert space. The approach reduces the three-level scheme to an equivalent two-level scheme and applies separation of stationary inhomoge…
Generated abstract This paper examines why the faces of the hexagonal prism in quartz crystals often fail to grow, despite being morphologically expressed, and under what natural conditions their growth occurs. Using X-ray diffraction topography of natural quartz crystals from Kazakhstan and the Southern Urals, the au…
Generated abstract This note estimates how many errors are corrected by Reed decoding of binary Reed-Muller codes beyond the usual guaranteed minimum-distance bound. Using combinatorial estimates for the parity distribution of errors across coordinate groups, Fourier coefficient representations, and asymptotic probabi…
Generated abstract The paper examines the use of Faddeev equations with a separable Hilbert-Schmidt expansion of two-particle amplitudes for calculating zero-energy electron scattering on ground-state hydrogen. The authors derive integral-equation systems for singlet and triplet scattering lengths, exploit symmetry re…
Generated abstract The paper studies the asymptotic deflection of a finite viscoelastic beam of variable cross-section resting on a Winkler elastic foundation, with hereditary material behavior represented by an integral kernel. Using Tauberian theorems of Paley, Wiener, and Gelfand type, it derives conditions under w…
Generated abstract This note proposes nonlinear light scattering by static optical inhomogeneities, such as impurities or inclusions in transparent media, as distinct from stimulated scattering seeded by dynamic fluctuations. Using the Rayleigh single-scattering approximation for small, widely separated spherical part…
Generated abstract This note studies optimal sequential estimation of a location, or shift, parameter under squared error loss within a class of invariant stopping rules and equivariant terminal decisions. It defines optimality by analogy with Wald’s criterion, comparing risks among procedures whose expected sample si…
