Pion pair production in photon-photon collisions

The process γγ→π⁺π^? was measured using the detector MD-1 at VEPP-4. The two-photon reactionse ⁺ e ^?, μ⁺ μ^? and π⁺ π^? pair production were separated using scintillation counters, Cherenkov counters and shower-range chambers. A radiation widthГ _γγ(f ₂(1270))=3.1±0.35±0.35 keV was obtained.     

Sorption of Lower Alcohols with Activated Charcoals

The features of sorption of ethanol, isopropanol, butanol, isobutanol, and tert-butanol with activated charcoals under static conditions were studied.     

Phase Diagram and Properties of Glasses of the System Sb<Subscript>2</Subscript>S<Subscript>3</Subscript>-AgI

The phase diagram of the system Sb₂S₃-AgI was constructed from data of the differential thermal and X-ray phase analyses. The physicochemical properties of glassy and crystalline alloys were studied.     

Oxidative destruction of polymers under mechanical load

An influence of tensile stress on the rate of oxidative destruction of polydienes and polyolefins under the action of ozone has been found; the influence of molecular and submolecular parameters and macrochain segmental mobility on the kinetics of oxidation of polymers is discussed. It is shown that chemical processes, with sp³ to sp² carbon atom rehybridization in the main chain, can change the reactivity of molecules under the action of structural deformations. Both acceleration and deceleration of bimolecular reactions have been found.     

Structure Elucidator: a versatile expert system for molecular structure elucidation from 1D and 2D NMR data and molecular fragments

StrucEluc is an expert system that allows the computer-assisted elucidation of chemical structures based on the inputs of a series of spectral data including 1D and 2D NMR and mass spectra. The system has been enabled to allow a chemist to utilize fragments stored in a fragment database as well as user-defined fragments submitted by the chemist in the structure elucidation process. The association of fragments in this way has been shown to dramatically speed up the process of structure generation from 2D NMR data and has helped to minimize or eliminate the need for user intervention thereby further enabling the vision of automated elucidation. The use of fragments has frequently transformed very difficult 2D NMR elucidation challenges into easily solvable tasks. A strategy to utilize molecular fragments has been developed and optimized based on specific challenging examples. This strategy will be described here using real world examples. Experience gained by solving more than 150 structure elucidation problems from a variety of literature sources is also reviewed in this work.     

Tetrachlorosilane Consumption in Radio Frequency Glow Discharge

Time-resolved mass spectrometry was used for analysis of the plasma reactions in radio frequency (RF) SiCl ₄ and SiCl ₄ –O ₂ discharges as functions of starting partial pressure and electrical power. Molecular concentrations of the reactants and products from SiCl ₄ alone and with O ₂ were obtained from the mass spectra and used for plotting the kinetic curves. The SiCl ₄ and O ₂ consumption rates were calculated from the kinetic curves and compared with results of theoretical simulation of the reaction. Direct electron impact decomposition was found to be the main pathway for pure SiCl ₄ conversion. On the contrary, the consumption of SiCl ₄ in the SiCl ₄ +O ₂ mixtures was largely chemical. The experimental macrokinetics are in agreement with a model in which oxidation is caused by the atomic oxygen.     

Surface tension anisotropy in the mechanics of ellipsoidal micelles

Expressions for the calculation of the surface tension at any point of ellipsoidal micelle surface in the directions of the main axes have been derived within the framework of the droplet model of molecular aggregates. It has been established that the anisotropy of the surface tension of an ellipsoid of revolution-shaped micelle depends on the ellipsoid shape factor and the polar angle. At low shape factors, the anisotropy is low in the vicinity of points with maximum and minimum curvatures and it reaches its maximum value at angles of ≈π/4. The maximum is shifted toward larger polar angles with an increase in the shape factor.     

Continuous Process for Obtaining Carbon Nanofibers

A continuous laboratory installation with a horizontal reactor for obtaining carbon nanofibers by catalytic pyrolysis of methane was developed and tested. The conversion of methane at 600°C was studied and the nanofiber output capacity of the continuous installation under the optimal conditions on a Ni-La₂O₃ catalyst was determined.     

Angular distribution of electrons from powerful accelerators

A technique for measuring the angular distribution of electrons escaping from the center of the window of the IGUR-3 and ÉMIR-M powerful accelerators (designed at the All-Russia Institute of Technical Physics, Russian Federal Nuclear Center) into ambient air is presented, and measurement data are reported. The number of electrons is measured with cable detectors (the solid angle of the collimator of the detector is ≈0.01 sr). The measurements are made in three azimuthal directions in 120° intervals in the polar angle range 0–22°. The angular distributions of the electrons coming out of the accelerators are represented in the form of B splines.