Dimerization of Sodium Enolates of Malonic Ester and Acetylacetone Effected by the Action of 4-Methyl-3,4-dibromotetrahydropyran

Russian Journal of Organic Chemistry -     

Synthesis of polymers containing azo groups in the main chain from <Emphasis Type="Italic">m</Emphasis>-phenylenediamine: Study of doping

Synthesic approach to polymers containing azo groups was developed on the basis of diazotization and azo-coupling reaction of m-phenylenediamine (m-PDA) with various ratio m-phenylenediamine-sodium nitrite. Doping of poly(azoaminophenylenes) with iodine, perchloric and hydrochloric acids was examined. Electroconductivity increases in the case of iodine to 0.2 S mol⁻¹, of perchloric acid, to 7×10⁻³ S mol⁻¹, and at the action of hydrogen chloride it is virtually unaffected. According to the ESR spectra, at the doping with iodine and perchloric acid electroconductivity enhances generally due to the mobility increase of the charge carriers (polarons).     

Influence of the external noise intensity on the kinetics of ligands binding to receptors

The average, variance, correlation function and the spectral density of ligand–receptor complexes in the presence of the external Langevin noise are calculated and their characteristics are defined. The analysis of the experimental data using the formulas derived in this work enables one to obtain a new information on the process of forming of ligand–receptor complex, namely, the constants rates of formation and the decay of the ligand–receptor complex.     

Diffraction reflection of light on natural periodic inhomogeneities of a crystal with open surface of wave vectors

The forms of the surface of wave vectors for an extraordinary wave in the presence and absence of absorption are discussed. The normal transmission of light through a plane-parallel layer of a crystal with an open surface of wave vectors is considered. The diffraction reflection of light on natural periodic inhomogeneities of a crystal is studied. The frequency dependence of the reflection coefficient is calculated.     

Seeking and investigating isospin-two narrow dibaryon resonances in neutron-proton interactions at P n =5.20±0.13 Gev/c

The results are presented that are obtained from searches for and an investigation of isospin-two narrow resonances in the effective-mass spectrum of ppπ⁺ combinations originating from the reaction np → ppπ⁺π^?π^? induced by P _n =5.20±0.13 GeV/c neutrons. Data subjected to our analysis come from the 1-m hydrogen bubble chamber installed at the Laboratory for High Energies, Joint Institute for Nuclear Research (Dubna), and exposed to a beam of quasimonochromatic neutrons. Narrow structures in the effective-mass spectrum of ppπ⁺ combinations are found at 2175, 2221, 2321, 2398, 2471, 2525, 2596, and 2709 MeV/c ². The experimental widths of the resonances are determined primarily by the instrumental resolution. The branching fractions for various channels through which the 2596-MeV/c ² resonance decays are determined to be (83±23)% for the Δ ₃₃ ⁺⁺ p channel, (10±3)% for the (BB) ₂₀₉₅ ⁺⁺ π⁺ channel, and (7 _?7 ⁺¹⁵ for the ppπ⁺ channel; here, (BB) ₂₀₉₅ ⁺⁺ is a dibaryon in the two-proton system with a mass around 2095 MeV/c ². A qualitative analysis of the spins of the 2596-and 2709-MeV/c ² resonances is performed.     

Search for and study of low-mass scalar mesons in reactions np → npπ+π? at neutron beam momentum Pn = (3.83 ± 0.12) GeV/c

The results of a search for and study of the scalar 0⁺ [0⁺⁺] σ₀ mesons in a π⁺π⁻ system produced in the reaction np → npπ⁺π⁻ at the quasi-monochromatic neutron beam momentum P _n = (3.83 ± 0.12) GeV/c are presented as derived from analyzing the data obtained during the exposure of a 1-meter hydrogen bubble chamber at the Laboratory of High Energy, Joint Institute for Nuclear Research (LHE JINR). It is found that there is a significant bump in the effective mass distribution at M_{p⁺ p^-} = (404 ±5)MeV/c²M_{\pi ^ + \pi ^ - } = (404 \pm 5)MeV/c^2 and Γ_res^exp = (14±5.4) MeV/c ², which is observed with more than four standard deviations from the background. The spin of this resonance is estimated to be most likely equal to zero. Its quantum numbers are found to be 0⁺ [0⁺⁺].     

X-ray-to-optic image converter for visualization of crystal structure defects

The designed luminescent screen for an X-ray-to-optical image converter showed a high spatial resolution and a high efficiency in X-ray absorption and conversion.     

Λ-Baryon production in π ± N interactions

The process of Λ-baryon production in πp collisions is considered. The contribution of the string-junction mechanism to the strange-baryon production in meson-baryon scattering is analyzed. The results of numerical calculations in the framework of the quark-gluon string model are in reasonable agreement with the data. The text was submitted by the authors in English.     

An error estimate for the finite difference scheme for one-phase obstacle problem

In this paper we consider the finite difference scheme approximation for one-phase obstacle problem and obtain an error estimate for this approximation.