Dynamic Modeling of an Active Damper

A dynamic model of the starting current of an active damper based on a magnetorheological elastomer is described, Experimental data for the damper are derived.     

On the Advantages of Local Measurement of Coercive Force of Ferromagnetic Objects Based on Internal Field

Russian Journal of Nondestructive Testing - It has been shown that locally measuring coercive force $${{H}_{{\text{c}}}}$$ based on the magnitude of demagnetizing current has a fundamental...     

The effect of implantation of P ions on the photoluminescence of Si nanocrystals in SiO<Subscript>2</Subscript> layers

The effects of implanting 10¹³–10¹⁶ cm^?2 P ions and subsequent annealing at 600–1100°C on the photoluminescence of Si nanocrystals formed preliminarily in SiO₂ layers were studied. Quenching of the 780-nm luminescence band related to nanocrystals was observed immediately after the implantation of 10¹³ cm^?2 P ions. The recovery of emission from partially damaged nanocrystals was noticeable even after annealing at 600°C; however, heat treatments at 1000–1100°C were needed when the amorphization-threshold dose was exceeded. Intensification of luminescence was observed as a result of heat treatments of SiO₂ layers implanted with low doses of P ions; if the P content was higher than ～0.1 at. %, the recovery of luminescence was promoted. The former effect is attributed to impact crystallization of nanoprecipitates. The latter effect is attributed to the promotion of crystallization by an impurity and (along with the dose dependence of postannealing luminescence) is considered an indication that P atoms penetrate into the Si nanocrystals. Contrary to a number of estimations, introducing P does not result in the quenching of luminescence due to Auger recombination. This discrepancy is attributed to the interaction of charge carriers with the nuclei of donors.     

Use of γ Radiation from Short-Lived Fission Products for Detecting <Superscript>235</Superscript>U and <Superscript>239</Superscript>Pu

It is suggested that γ radiation with E _γ > 4900 keV from short-lived fission products produced by thermal neutrons be used to detect ²³⁵U and ²³⁹Pu in samples. A time regime is substantiated: 120 sec irradiation, 60 sec holding time, and 120 sec measurement time. The contribution of the reaction (n, p) on fast neutrons is studied.__________Translated from Atomnaya Energiya, Vol. 98, No. 5, pp. 365–370, May 2005.     

Performance enhancement in high-<Emphasis Type="Italic">T</Emphasis><Subscript><Emphasis Type="Italic">c</Emphasis></Subscript> ceramics through melting by Joule heating,infrared lamps,and laser radiation

We have analyzed experimental data on the effect of short-term melting followed by recrystallization on the microstructure and critical current density of YBa₂Cu₃O_{7 ? x} , Bi₂Sr₂CaCu₂O_{8 ? x} , and Bi₂Sr₂Ca₂Cu₃O_{10 ? x} high-T _c ceramics. The ceramics were melted using different heat sources: infrared lamps, laser radiation, and electric current. A significant increase in the critical current density of Bi₂Sr₂Ca₂Cu₃O_{10 ? x} ceramics (by a factor of 40 at 20 K and by a factor of 8 at 77 K) was achieved using cw CO₂ laser irradiation. Melting TiC-doped (0.1%) Bi₂Sr₂Ca₂Cu₃O_{10 ? x} ceramics with a CO₂ laser, followed by annealing, insured an even larger increase in critical current density: by a factor of 35 at 77 K. We have calculated the thickness of the molten layer produced by laser heating of high-T _c ceramics.     

Nitrogen alloying of the 12% Cr martensitic-ferritic steel

The influence of the nitrogen content on the structure and mechanical properties of heat and corrosion resistant 12% Cr martensitic-ferritic steel developed at the Central Research Institute of Structural Materials Prometey has been studied. Steel containing 0.061 wt % nitrogen possesses a high level of mechanical properties. The decrease in the nitrogen content to 0.017 wt % leads to an increase of structurally free ferrite fraction in the steel, a decrease in the density of dislocations, a decrease of structural dispersity and the absence of finely dispersed precipitates of niobium and vanadium nitrides and carbides. As a result, there is a decrease in the strength properties, especially in the heat resistance.     

Installations for producing electrospark erosion- and abrasion-resistant coatings on the blades of steam turbines of thermal and nuclear power plants

This article is devoted to the creation of installations for generating electric spark erosion- and abrasion-resistant protective and strengthening coatings on the blades of steam turbines of thermal and nuclear power plants such as GBF and KGB, developed and manufactured by the OAO VTI. A characteristic feature of the installations is the fact that they are equipped with electromechanical exciters with a high service life and reliability compared to electromagnetic ones. The study data for the electrical characteristics of the KGB-5 installation are presented.