Vacuum Conditions and the Lifetime of a Single-Charged Helium Ion Beam in the Booster Synchrotron of the NICA (First Run)

JETP Letters - The results of the first run (December 2020) for the commissioning of the new superconducting synchrotron Booster at the Joint Institute for Nuclear Research are presented. Vacuum...     

Effect of MQ-copolymer and polymethylsilsesquioxane on thermal and mechanical properties of highly filled polyisoprene

Russian Chemical Bulletin - Highly filled vulcanizates based on polyisoprene, organosilicon fillers (polymethylsilsesquioxane and MQ-copolymers), and p-quinone dioxime derivative as a rubber...     

Instability of the interface of two gases accelerated by a shock wave

Results are presented of an experimental study of the stability of the interface of two gases traversed by ashockwave. It is found that the interface is unstable both in the case of shock wave passage from the lighter to the heavier gas and for passage in the opposite direction. The interface disturbance grows linearly with time in the first approximation.     

Phase state and rheology of organosilicon nanocomposites with functionalized hyperbranched nanoparticles

The phase equilibrium in a system of linear polydimethylsiloxane–functionalized nanoparticles 1.2–2.2 nm in size with a core made of hyperbranched silica and a periphery of decyl groups has been studied by laser interferometry method. Phase diagrams of the studied systems fit the amorphous phase equilibrium with UCST increasing with the nanoparticle size. The mixtures present nanoparticle solutions in the linear polymer or emulsions of a saturated solution of one component in a saturated solution of other component depending on the components ratio. Dilute, concentrated, or highly concentrated dispersions show individual features of the rheological behavior. For each colloid chemical and phase states of mixtures, the viscosity and viscoelastic properties have been investigated in a wide temperature range. The obtained results have been compared with the previous data for mixtures of decylated nanoparticles and polyisobutylene.     

Corrosion Behavior of Quasi-Crystalline Alloys of the Al–Cu–Fe–Cr System in Alkaline Media

Russian Journal of Electrochemistry - The electrochemical behavior of three alloys of different composition in the system Al65Cu25Fe10 – хCrх is studied by the potentiodynamic...     

Hyperbolic equations with third-order symmetries

We present a complete list of nonlinear one-field hyperbolic equations with integrable third-order x and y symmetries. The list includes both equations of the sine-Gordon type and equations linearizable by differential substitutions.     

Methods of optical diagnostics of electron-positron beams and interaction between plasma and high-current electron beam

Optical diagnostics is widely used, both in plasma-physics experiments and in measuring parameters of electron and positron beams in accelerators. In doing so, the approaches with the same methodological base are often applied, which is explained by similarity of certain properties of objects under study despite the fact that these fields of physics are absolutely specific and require using the specialized techniques. The possibility of close contacts and cooperation among scientists concerned with similar problems in different fields of physics contributes to the fruitful exchange of ideas and helps to overcome these problems. It is especially characteristic of the Budker Institute of Nuclear Physics, Siberian Branch of Russian Academy of Sciences, which is famous for pioneering works in the field of electron-positron colliders and controlled thermonuclear fusion. The first part of this paper presents a review of optical diagnostics of the stationary beam parameters in cyclic accelerators of electrons and positrons. The only techniques considered are those that became the recognized tools at colliders and storage rings of the latest generation, without which the routine operation of the facility is difficult to imagine. The second part of the paper describes optical diagnostics used in experiments of heating the plasma by a high-current electron beam.     

Overview of diagnostic methods used in shock-tube investigations of mixing induced by Richtmyer–Meshkov instability

We present an overview of the diagnostic methods used in shock-tube investigations of mixing induced by Richtmyer–Meshkov instability. The different diagnostic techniques are first briefly presented, and then reviewed in a simple single table, which lists their advantages and disadvantages, their technological characteristics and domain of validity, the physical parameters measured, the laboratory in which they were developed and an assessment of their mean cost. Received 19 November 1997 / Accepted 3 March 1998     

Optimization of basis sets for isoelectronic series of closed-shell atoms in Hartree-Fock-Roothaan calculations

Optimization of the nonlinear parameters (orbital exponents) of basis functions in Hartree-Fock-Roothaan calculations may be canied out with a high degree of accuracy. A scheme using second-order methods is suggested for optimization of the orbital exponents of Slater type basis functions defining the ground state of closed-shell atoms. An exact fomula is derived for calculating the partial second derivatives of energy with respect to nonlinear parameters in temis of the density matrix. In bases of isoelectronic series, the orbital exponents are shown to be the linear functions of the charge of the ion nucleus. Optimization calculations are reported for He, Be, Ne, and Mg atoms and their isoelectronic series. Translated fromZhumal Struktumoi Khimii, Vol. 41, No. 2, pp. 217–228, March–April, 2000