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The effect of a magnetic spring is observed in electromechanical devices with limited pole sizes. Simultane-ous changing of the system magnetic conductivity after a relative displacement of the poles causes mag-netic tension forces. These forces in electromechanical magnetic fluid dampers have their own specific characteristics which have not been studied before. All this requires studying the effect of a magnetic spring on the damper power characteristics, estimating the effect of the properties of a magnetorheological suspension on the magnetic spring strength, nature of its change and combination of the action of magnetic forces and viscosity resistance to the piston movement. To do that, it is important to analyze the effect of a magnetic spring in statics, at a slow movement of the piston and its dynamic oscillations. The studies were based on the theory of natural experiment and methods of processing experimental results. We have obtained and analyzed dependences of the resistance force of the electromechanical magnetic fluid damper for different vibration frequencies and magnetic inductions. The effect of magnetic spring forces on the damper power characteristic has been investigated. It has been found how the damper resistance force is affected by the magnetic and hydrodynamic components. The use of a damper with alternating elements with high and low magnetic conductivities makes it possible to change the strength characteristic of electromechanical magnetic fluid dampers. The proportion of the force controlled by the magnetic field reaches 75 % of the total effort. The use of the magnetic spring effect allows increasing the damping efficiency at small amplitudes and vibration frequencies. Increasing the magnetic properties of a magnetorheological suspension enhances the effect of a magnetic spring if the piston is non-magnetic, and weakens it if it is a magnetic one. When the magnetic induction rises, the effect of the magnetic spring increases. By changing the initial piston position, it is possible to obtain an asymmetrical power characteristic, for example, without using valves and spools, to increase the rebound force and to reduce the compressive force. If there are no moving parts, the damper reliability increases.

The algorithm for analytical calculation of a power characteristic of magnetorheological (MR) dampers taking into account the rheological properties of MR fluid is considered. The nonlinear magnetorheological characteristics are represented by piecewise linear approximation to MR fluid areas with different viscosities. The extended calculated power characteristics of a MR damper are received and they coincide with actual results. The finite element model of a MR damper is developed; it allows carrying out the analysis of a MR damper taking into account the mutual influence of electromagnetic, hydrodynamic and thermal fields. The results of finite element simulation coincide with analytical solutions that allows using them for design development of a MR damper.

The results of a study of the dynamics of an induced attenuation of light in optical fibers exposed to γ radiation are presented. The doses were as high as ∼10 and 100 Mrad at dose rates of ∼10 and ∼100 rad/s. Two types (silica–silica and polymer–silica) of fibers produced by INFOS (Russia), Polymicro (USA), and Hestibel (Turkey) were investigated.

The project "Dubna Electron Synchrotron" (DELSY) is aimed to construct a synchrotron radiation source of the 3d generation at the Joint Institute for Nuclear Research. The DELSY synchrotron radiation source will be constructed on the base of the accelerator facility of the Institute for Nuclear Physics and High Energy Physics (NIKHEF), Amsterdam, the Netherlands. This accelerator facility consists of a linear electron accelerator MEA (Medium Energy Accelerator) for the electron energy of 700 MeV and the electron storage ring AmPS (Amsterdam Pulse Stretcher) for the maximum electron energy of 900 MeV at the circulating beam current of 200 mA. The DELSY storage ring is supposed to be constructed with the use of the "Amsterdam Pulse Stretcher" (AmPS) [1] storage ring the focusing system of which will be essentially modified: the ring circumference will be approximately 1.5 times smaller, the electron energy will be increased up to 1.2 GeV and the focusing strength will be enhanced. These measures will allow obtaining the beam emittance at least ten times smaller which subsequently increases the synchrotron radiation brilliance by several orders of magnitude. The rigging of the DELSY ring with the insertion devices — the superconducting wiggler with the magnetic field of 10 T and the so-called "vacuum hybrid miniundulator" is the principle feature of the new synchrotron radiation source. Both devices developed by Budker INP, Novosibirsk, will allow to enrich the DELSY characteristics as the synchrotron radiation source expanding its radiation spectrum in the region of the hard X-rays and increasing its brilliance up to 3 ⋅10 18

The lifetime of the 236U nucleus is measured in the range of excitation energies Ex = 6.7–11.5 MeV by a method based on the shadow (blocking) effect. The results obtained, as well as those of an earlier measurement of the lifetime for the 239U nucleus in the range Ex = 6.4–9.1 MeV, are compared with the results of calculations based on the level density ρ(Ex) in the Fermi-gas model and on the empirical level density ρ(E)x) calculated as a result of an analysis of(n, γ) and (n, n') cross sections. An increase of excitation energy produces a substantial reduction in the rate of decrease of the lifetime at Ex ≳ 7.5 MeV for both compound nuclei as compared to the theoretical dependence τ(ex).