Ion beam parameters of a plasma accelerator

The aim of the present investigation was to determine the dependences of the current density, the energy, and the divergence of the ion beams of an UZDP-type source (a plasma accelerator with closed electron drift in the accelerator channel and an extended zone of ion acceleration) on the parameters which determine its performance, and to establish qualitative relationships between these values.Translated from Izvestiya Vysshikh Uchebnykh Zavedenii, Fizika, No. 2, pp. 20–24, February, 1987.     

Poincaré series in SL(3, R)

It is shown that in the spectral decomposition of the one-parameter Poincaré series from SL(3, R) involves only the discrete spectrum, induced from SL₂ and not the discrete spectrum of SL₃ itself. Translated from Zapiski Nauchnykh Seminarov Leningradskogo Otdeleniya Matematicheskogo Instituta im. V. A. Steklova AN SSSR, Vol. 160, pp. 37–40, 1987.     

Cluster states in the neutron excess nucleus 22Ne

High-spin states of the ²²Ne nucleus in the excitation energy range of 15–30 MeV have been studied. The angular correlation method has been used to determine the spins of excited states. A number of new states with high angular momenta—20.0 MeV (9^?), 20.7 MeV (11^?), 21.6 MeV (9^?), 22.2 MeV (12⁺), and 25.0 MeV (9^?)—have been revealed. They are intensely populated in the reaction ¹⁴C(¹²C, α₁)²²Ne* → α₂ + ¹⁸O and correspond to the rotational bands of various structures.     

Probing shear-band initiation in metallic glasses

In?situ acoustic emission monitoring is shown to capture the initiation of shear bands in metallic glasses. A model picture is inferred from stick-slip flow in granular media such that the origin of acoustic emission is attributed to a mechanism of structural dilatation. By employing a quantitative approach, the critical volume change associated with shear-band initiation in a metallic glass is estimated to be a few percent only. This result agrees with typical values of excess free volume found in the supercooled liquid regime near the glass transition temperature.     

X-ray absorption investigation of the electronic structure of the CuI@SWCNT nanocomposite

The Cu 2p, I 3d, and C 1sX-ray absorption spectra of the CuI@SWCNT nanocomposite prepared by filling single-walled carbon nanotubes (SWCNTs) with the CuI melt by the capillary technique have been measured with a high-energy resolution using the equipment of the Russian-German beamline at the BESSY electron storage ring. In order to characterize the electronic structure of the nanocomposite and possible changes in the atomic and electronic structures of CuI and SWCNTs in the CuI@SWCNT nanocomposite, the spectra obtained have been analyzed in the framework of the quasi-molecular approach by comparing with the spectra of the pristine (CuI and SWCNT) and reference (CuO) systems. It has been revealed that the encapsulation of the CuI compound inside SWCNTs is accompanied by changes in the electronic structure of CuI and SWCNTs due to the chemical interaction between the filler and carbon nanotubes and the change in the atomic structure of CuI.     

Approximation estimates for convolution classes in terms of the second modulus of continuity

We establish the best approximation estimates for certain convolutions whose kernels are entire functions of exponential type in terms of the second modulus of continuity. The Jackson-type inequalities for even-order derivatives are particular cases of our estimates.     

Synthesis of organized mesoporous γ-alumina templated with polymer–colloidal complex

Mesoporous γ-Al₂O₃ materials with high surface area and a narrow pore size distribution were synthesized by facile sol–gel procedure with application of the polymer–colloid complex as a template.     

Synthesis and nitration of condensation products of sulfamates with aliphatic amines and formaldehyde

A method for the synthesis of 5-alkyl-1,3-dinitro-1,3,5-triazacyclohexanes and linear polynitramines was proposed. It includes the reaction of aliphatic amines with sulfamates and formaldehyde and nitration of the reaction products. The yield and composition of nitramino derivatives depend on the conditions of the condensation and nitration. Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1088–1091, June, 2000.     

On a Representative Volume in the Micromechanics of Particulate Composites

A rectangle filled with closely packed spheres of random size and properties is considered as a micromechanical model of a two-phase particulate composite. A numerical simulation is used to determine the effective mechanical properties of the assembly and their scatter as a function of the number of spheres. It is shown that, in a system with relatively small number of particles (up to 300), the scatter of Young's modulus decreases with the system size. However, the rate of the scatter decrease becomes smaller with growing size of the system, so that the convergence to zero most likely takes place at infinity.