Energy exchange between a test charge and an unstable electron beam

An investigation is made of the interaction between a test charge and an electron beam which is convectively unstable against plasma oscillations. An analysis is made of the negative-mass instability of the longitudinal motion. Expressions are derived for the reaction force exerted by the electron plasma polarized by the moving charge and for the diffusion tensor arising from electric field fluctuations. The approximation of uniform rectilinear motion of a test particle is used to estimate the systematic and diffusion components of the rates of change in its energy. It is shown that in this case, interaction with an unstable electron beam leads to acceleration of the particle in respect to the longitudinal degree of freedom (antifriction) and under certain conditions enhances the friction effect (cooling) in respect to the transverse degrees of freedom. An assessment is made of the possibility of obtaining an overall positive friction effect by using a special “sweeping” procedure whereby the longitudinal velocity of the electron beam is changed in a specific manner consistent with the cooling process. Zh. Tekh. Fiz. 67, 58–61 (November 1997)     

Search for exotic baryons with hidden strangeness in proton diffractive production at the energy of 70 GeV

The first preliminary results from the upgraded SPHINX spectrometer, working in the proton beam with the energy of 70 GeV of the IHEP accelerator, are presented. The data for the reaction p + N ? [Σ⁰ K ⁺] + N based on new statistics are in good agreement with our previous data and strongly support the existence of the X (2000) state (with an increase in statistics for this state by a factor of ～5). We also observed radiative decay of Λ(1520) → Λγ. The significant increase in statistics for many diffractive-production reactions will allow us to study them in great detail.     

Free n-groups

The structure of n-subgroups of free n-groups is described.Translated from Matematicheskie Zametki, Vol. 8, No. 4, pp. 499–507, October, 1970.     

Design of infrared laser pulses for the deexcitation of highly excited homonuclear diatomic molecules

We explore the possibility of using shaped infrared laser pulses to deexcite a homonuclear diatomic molecule from its highest vibrational state down to its ground vibrational state. The motivation for this study arises from the need to deexcite alkali metal dimers in a similar way so as to stabilize molecular Bose-Einstein condensates. We demonstrate that for the case of the H(2) molecule, where it is possible to evaluate all the necessary high accuracy ab initio data on the interaction of the molecule with an electric field, we are able to successfully design a sequence of infrared laser pulses to accomplish the desired deexcitation process in a highly efficient manner.     

Features of Propene Oxidation in Argon,Carbon Dioxide and Water Vapor Media at a High Density of Reagents

The features of propene oxidation in high-density mixtures of C₃H₆/O₂ ([C₃H₆]₀ = 0.23–0.25 mol/dm³, [O₂]₀ = 0.76–0.82 mol/dm³), diluted with argon, carbon dioxide and water vapor at uniform heating (1 K/min) to T ≤ 620 K are investigated for the first time. From the time dependences of reaction mixtures temperature it is found that propene self-ignition occurs at 465 K and does not depend on the nature of the diluent. Using mass spectrometry analysis it is demonstrated that in the composition of the products of propene oxidation in the Ar and CO₂ medium predominate methanol, acetaldehyde, acetone, acetic acid and formaldehyde; in the oxidation in the H₂O medium, only small amof O₂ in the oxidation of propene increases in ounts of these substances were registered. Degree of consumption the following order: CO₂ ? Ar < H₂O, which is a consequence of the involvement of CO₂ and H₂O molecules in chemical transformations. Mechanisms of the observed processes are discussed.     

Synthesis of α-monoglycerides of aromatic acids

The synthesis of -monoglycerides of aromatic acids has been performed by the transesterification of the methyl esters of the corresponding acids with glycerol. The structures of the compounds obtained have been confirmed by their IR, UV, and¹H and¹³C NMR spectra.A. B. Bekturov Institute of Chemical Sciences, Academy of Sciences of the Republic of Kazakhstan, Almaty, fax (3272) 61 57 65. Translated from Khimiya Prirodnykh Soedineii, No. 4, pp. 452–457, July–August, 1999.     

Isomorphisms of free decompositions of Г-operator groups with a regular group of operators Г

A theorem on the existence of isomorphic continuations for free decompositions of a -operator group with a group of operators acting regularly is proved.Translated from Matematicheskie Zametki, Vol. 4, No. 3, pp. 355–360, September, 1968.The author is deeply grateful to A. G. Kurosh for supervising the research.     

Catalytic dehydrogenation of 4-ethylpyridine

A study is made of the dehydrogenation of 4-ethylpyridine over a mixed oxide catalyst, at atmospheric pressure, using dilution with steam, carbon dioxide, and nitrogen. Maximum yields of 4-vinylpyridine are obtained when the dehydrogenation is carried out at 620° C, feed rate 500 ml/l catalyst/hr, and CO₂ dilution of the 4-ethylpyridine at a mass ratio of 12–13.