Recent Papers

Characteristics of Spherical Flames at the Formation Stage

This paper investigates the formation stage of centrally ignited spherical flames, addressing the discrepancy between theories that assume immediate establishment of plane-flame characteristics and observations indicating gradual development of burning velocity and temperature. Experiments on a prop…

Effect of structure and medium on the reactivity of hydrocarbons in their interaction with free methyl radicals in the liquid phase

This study examines how hydrocarbon structure and reaction medium affect hydrogen abstraction by free methyl radicals in the liquid phase. Using competing reactions with tritium-labeled n-heptane as a standard and methyl radicals generated by thermal decomposition of acetyl peroxide, relative overal…

Erycordin and Desglucoerycordin – New Cardiac Glycosides

This study characterizes erycordin, a previously undescribed cardiac glycoside isolated from the herb of Erysimum cheiranthoides, and its related monoglycoside desglucoerycordin. The authors use enzymatic and chemical hydrolysis, acetylation, oxidation, chromatography, elemental analysis, molecular …

On Analytic Solutions of the Tricomi Equation

This note studies analytic solutions of the Tricomi equation near the origin and in the entire complex plane, using a representation of solutions in terms of two analytic functions of one variable. Boundary value problems are considered in which values are prescribed on the line y = 0 and on curves …

Physical Investigation of the Yellow and Red Forms of Mercuric Oxide

This paper examines the long discussed color difference between the yellow and red forms of mercuric oxide, testing whether it can be explained solely by particle size or whether other solid-state factors are involved. The authors compare the two forms using sedimentation measurements, powder X-ray …

Decomposition of Cyclopentadienyl Metal Compounds by Bromine and Potassium Hypobromite

On Small Perturbations of Torus Automorphisms

The paper studies small smooth perturbations of hyperbolic automorphisms of the torus, focusing first on the two-dimensional case. Using successive approximations, it constructs invariant expanding and contracting families of nonclosed curves for the perturbed map, then proves a simultaneous straigh…

On functions satisfying the differential equation $x^2y'''+3xy''+y'+x^2y=0$

This note solves the third order linear ordinary differential equation with variable coefficients x squared y triple prime plus 3 x y double prime plus y prime plus x squared y equals 0 by an operational method. After a change of variables, the equation is related to an operator of the form d/dt, t …

Synthesis of Dihydroambrettolide

A synthetic route to macrocyclic musk lactones is described using cyclic ketones and unsaturated alcohol derivatives as starting materials, illustrated by the preparation of dihydroambrettolide, or hexadecanolide, from cyclopentanone and undecenol acetate. The method involves tert-butyl peroxide ini…

New Synthetic Sodium Zeolites and Their Adsorption Properties

This paper reports the low-temperature hydrothermal synthesis of sodium zeolites in the system Na2O, Al2O3, SiO2, H2O, extending beyond the known NaA and NaX types. The authors describe three additional products, designated B, E, and Zh, compare their compositions, refractive indices, and X-ray char…

PAIR INTERACTIONS OF ATOMS AND PROPERTIES OF X-SUBSTITUTED METHANES AND THEIR RADICALS

This paper develops a pair interaction approach for relating the structure of substituted methanes to molecular and radical properties. Assuming that heats of formation and other physicochemical properties can be expressed as sums of atom pair contributions, the author derives quadratic formulas for…

On Estimates of the Chromatic Number of Connected Graphs

This paper studies extremal values of the chromatic number among connected simple graphs with a fixed number of vertices and edges. The authors define upper and lower chromatic numbers for the class of connected graphs with n vertices and p edges, then prove exact formulas for both quantities. The p…

On Minimal Systems and Quasicomplements in a Banach Space

The paper studies minimal systems, total conjugate systems, and quasi-complements in separable Banach spaces. It proves that a complete minimal system in a subspace, under a totality condition on its conjugate system, can be extended to a complete minimal system in the whole space with a total conju…

On the interaction of polymers and copolymers of 2-methyl-5-vinylpyridine with aromatic nitro compounds

This paper examines the interaction of poly-2-methyl-5-vinylpyridine and its styrene copolymers with aromatic nitro compounds, motivated by the reactivity of pyridine nitrogen atoms toward addition reactions. The authors prepared the polymers and copolymers, followed viscosity changes during heating…

Effect of Pressure, Temperature, and Electric Field on the Behavior of Molecular Patterns

This paper investigates the origin and stability of molecular emission patterns observed in an electron projector during adsorption of gases and vapors on a field emitter. By varying pressure, anode voltage, and temperature for substances including hydrogen, nitrogen, oxygen, carbon dioxide, inert g…

On the Process of Producing Acrylonitrile from Propylene and Ammonia

This study examines the one-stage oxidative ammonolysis of propylene with ammonia and atmospheric oxygen as a route to acrylonitrile over a catalyst composed of variable-valence metal oxides. Laboratory flow experiments with a fixed catalyst bed investigated the effects of catalyst grain size, tempe…

Templates for Interpreting the Formation of a Magnetic Field

This paper addresses the interpretation of transient magnetic-field establishment measurements used in electrical prospecting, particularly for regional tectonic studies in oil-bearing areas. The authors compute theoretical apparent-resistivity curves for three-layer and four-layer horizontally stra…

On the Theory of Turbulence in Inhomogeneous Flows

This paper develops a spectral description of weak inhomogeneous turbulence in incompressible viscous flows, focusing on how nonuniform mean motion can amplify turbulent fluctuations. Starting from averaged Navier Stokes equations and neglecting higher order correlations in the initial approximation…

Shape of the Surface of a Liquid Losing Weight

This paper examines how the free surface of water in a glass vessel changes as effective gravity is reduced to zero, a problem motivated by observations of liquids during spaceflight. Using capillary equilibrium equations for a wetting liquid in a cylindrical vessel, the author relates meniscus prof…

Electro-seismic effect

This paper proposes and experimentally investigates an electro-seismic effect reciprocal to the seismo-electric effect of the second kind: mechanical oscillation of a porous rock or similar rigid framework containing dissociated salt solution under an applied alternating electric potential. Laborato…

Semigroups of continuous transformations

This paper studies when a topological space can be recovered from the semigroup of its continuous self-transformations. It proves that completely regular spaces containing a simple arc are characterized up to homeomorphism by isomorphism of these semigroups, using the minimal two-sided ideal of cons…

ON THE CLASSIFICATION OF FORMAL ABELIAN GROUPS

This paper studies the classification up to isomorphism of formal Abelian groups over an algebraically closed field of characteristic \(p > 0\), within the class for which multiplication by \(p\) is an isogeny and whose unipotent component consists only of additive groups. Using Dieudonné module met…

Polyazines – a New Class of Polymers with Conjugated Bonds

This paper examines polyazines as a little-studied class of polymers with conjugated bonds in the main chain, focusing on how chain structure affects thermal behavior and electrical conductivity. Polyazines were synthesized by polycondensation of hydrazine with glyoxal and several diketones, includi…

On the Relationship Between Coloration and the Structure of Janovsky Reaction Products

This paper examines the relationship between color and structure in the colored products formed by aromatic dinitro compounds in the Janovsky reaction with acetone and alkali. Using absorption spectra, the authors interpret the products as two quinoid monosalt complexes with distinct short- and long…

Symmetric Almost Symplectic Affine Connections on Hermitian Manifolds

This paper constructs a canonical symmetric affine connection on a Hermitian manifold, using the fundamental skew tensor associated with the metric and almost complex structure. Starting from Lemlein’s pencil of symmetric almost symplectic connections, it imposes additional invariant conditions invo…

Calculation of the Generation Power of a Plane-Parallel Layer

This paper calculates the generation power of a plane-parallel optical layer by accounting for nonlinear absorption, with the absorption coefficient taken to depend on radiation density. Using geometrical-optics expressions for the mean radiation density in the layer, the authors derive analytic con…

Cauchy-Type Integrals and Boundary Value Problems for Generalized Analytic Functions on Closed Riemann Surfaces

This paper studies Cauchy-type integrals and boundary-value problems for generalized analytic functions satisfying a first-order conjugate equation on closed Riemann surfaces of genus greater than two. It constructs modified Cauchy kernels without eigenfunctions, derives integral representations, an…

Recrystallization Diagram of Vanadium

This paper reports the construction of a first-order recrystallization diagram for cold-rolled carbothermic vanadium refined with cerium, a material for which prior recrystallization data were lacking. Specimens were deformed by 5 to 95 percent, annealed in vacuum at 750 to 1300°C, and examined by m…

Determination of the Rate Constant for the Reaction of Atomic Oxygen with Ethane

This study determines the rate constant for the reaction of atomic oxygen with ethane, O + C2H6 = OH + C2H5, a process for which earlier work had not provided kinetic parameters. The authors use the shift of the lower self-ignition limit of carbon monoxide and oxygen mixtures caused by small ethane …

Low-temperature polymerization of ethylene on an oxychromium catalyst

This study examines the low-temperature polymerization of ethylene on an oxinochromium catalyst in n-heptane at 75°, below the melting point of polyethylene, where the product remains suspended rather than dissolved. Polymerization experiments in a stirred autoclave measured ethylene uptake as a fun…

On Direct and Inverse Embedding Theorems for Some Spaces of Abstract Set Functions

The paper studies spaces of Banach-valued additive set functions introduced by Sobolev and relates their direct and inverse embedding properties to operator theory. It proves norm identities showing that such set functions generate continuous, absolutely continuous, or completely continuous linear o…

Study of the Catalyzed Crystallization Process by Raman Scattering Spectroscopy

This study examines the role of small additions of titanium dioxide in the heat-induced crystallization of a spodumene-composition glass-forming system, using Raman light-scattering spectra from samples subjected to successive heat treatments. The spectra indicate that heating weakens the band assoc…

On Totally Bounded Metric Spaces

This note characterizes total boundedness of a metric space in terms of the remainder of its bicompact extension associated with the metric proximity. It proves that a metric space is totally bounded if and only if this remainder is hereditarily normal, using a reduction to a countable uniformly dis…

Mass Spectrometric Study of Carbohydrates. Methyl Ethers of Monosaccharides

This paper examines the applicability of mass spectrometric fragmentation analysis to carbohydrate chemistry through the study of methyl ethers of monosaccharides. Mass spectra were recorded for several methylated pyranose and furanose derivatives, including glucopyranose, glucofuranose, galactopyra…

Study of the Properties of the Polymer–Semiconductor Interface

This paper investigates the polymer, semiconductor interface as a surface-physical factor in adhesion and in the protection of semiconductor devices by polymer coatings. Using n-type germanium specimens, the authors apply the field-effect method to measure changes in surface conductivity under a per…

A Generalization of a Theorem of V. A. Ambartsumian

This paper generalizes Ambartsumian’s inverse Sturm-Liouville uniqueness theorem from an interval to bounded two- and three-dimensional domains with Neumann boundary conditions. It proves that, for a bounded potential in the perturbed Laplace eigenvalue problem, convergence of the series of eigenval…

Activity coefficients of cesium chloride in $\mathrm{N}$-methylformamide

Activity coefficients of cesium chloride in N-methylformamide at 25 degrees C were determined to test how a highly polar nonaqueous solvent affects deviations from Debye-Hückel electrostatic theory. The authors measured the emf of a galvanic cell without transference using purified solvent, CsCl, Ag…

Wiener-Type Theorem for Series in Walsh Functions

This note proves a Wiener-type theorem for functions represented by absolutely convergent Walsh series on the unit interval. The argument treats these functions as a complete normed ring, after passing to a compact zero-dimensional space in which dyadic rational discontinuities are separated, and sh…

Electron density distribution in aluminum arsenide at $20$ and $-100^\circ$

This study examines the electron-density distribution and atomic scattering factors of aluminum and arsenic ions in aluminum arsenide with the sphalerite structure at 20°C and -100°C. Aluminum arsenide was synthesized in evacuated quartz ampoules, prepared as powder specimens under argon, and measur…

Arsenic and Phosphorus Polysulfides

This study examines the interaction of arsenic and phosphorus sulfides with sulfur-rich melts, where changes in physical properties suggest formation of distinct molecular or polymeric species beyond simple dissolution. Sulfur alloys containing arsenic or phosphorus were prepared in evacuated quartz…

Synthesis of Unsaturated Organosilicon Peroxides

This paper reports the synthesis and characterization of a series of unsaturated organosilicon peroxides containing vinyl or allyl substituents at silicon and one or two peroxide groups. The compounds were prepared by reacting unsaturated chloroorganosilanes with tert-butyl, tert-amyl, or cumene hyd…

Infinitesimal bendings of a convex surface with a generalized sliding boundary condition

This paper studies infinitesimal bendings of a simply connected convex surface of positive Gaussian curvature under a generalized sliding boundary condition, in which the displacement vector is required to be perpendicular along the boundary to a prescribed non-tangent vector field. The argument red…

On an Estimate for the Solution of a Parabolic Equation and Some of Its Applications

This note establishes an a priori estimate for solutions of a parabolic equation with zero boundary or initial data, under boundedness, continuity, and modulus conditions on the coefficients and forcing term. Using a probabilistic representation and trajectory continuity estimates for the associated…

Synthesis of Pyridylethyloxindoles

This paper reports the synthesis of pyridylethyloxindoles, compounds of interest because they combine pyridine and oxindole structural elements related to alkaloids and pharmacologically active indole derivatives. Arylaminoethylpyridines were haloacylated with chloroacetyl or bromopropionyl chloride…

Cycloalkylation of monoalkylbenzenes with cyclohexene

This study examines the cycloalkylation of toluene, ethylbenzene, and n-propylbenzene with cyclohexene using the boron trifluoride orthophosphoric acid molecular compound as catalyst. By varying reactant ratios, catalyst concentration, temperature, cyclohexene addition rate, and stirring time, the a…

On Hall's Theorem

The note studies Hall-type properties of finite groups relative to a set of primes, focusing on existence, conjugacy, containment, and solvability of corresponding Hall subgroups. It introduces the notion of a Pi-suitable subgroup and proves a generalization of a theorem of Philip Hall: if a normal …

Reaction of diethyl phenylphosphonite with $\alpha$ -, $\beta$ -, and $\gamma$ -chloroalkylalkylalkoxysilanes

The study examines the Arbuzov-type interaction of diethyl phenylphosphinite with a series of alpha-, beta-, and gamma-chloroalkylalkylalkoxysilanes to synthesize silicon-containing ethyl esters of alkylphenylphosphinous acids. Reaction conditions, times, and yields were compared across substituents…

On the Tunneling Effect in a Double Potential Barrier

This paper examines how a depression at the top of a chemical activation barrier can affect low temperature reaction rates through quantum tunneling. Using the quasiclassical approximation, it derives the transmission coefficient for an asymmetric double potential barrier and relates quasistationary…

Iron–Zirconium Phase Diagram

This study constructs a more complete phase diagram for the iron-zirconium system, with particular attention to the 16 to 52 percent zirconium region where earlier reports disagreed on intermediate phases. Alloys prepared by crucibleless arc melting were examined by differential thermal analysis, mi…

On Criteria for Complete Continuity of Linear and Nonlinear Integral Operators

This paper develops criteria for complete continuity of linear and nonlinear integral operators between Lebesgue spaces on finite measure domains, with particular attention to unbounded kernels. Using compactness in measure, equiabsolute continuity of integrals, and truncation of kernels, it proves …