Psychophysiological studies in the pre-school children

The behavior of 24 children, aged 3-6 years, was recorded on video-tape. Simultaneously the ECG was recorded telemetrically. These observations were made during two pre-school educational programs lasting 90 minutes each: "Didactic games" and "Elementary music and movement program". For each child a scale was developed to show the correlation of mean heart-rate and well defined motor-activity. It was evident that the mean heart-rate was higher during the music program than during the didactic program, corresponding to the higher motor-activity. But it was found that in the didactic program the variation of the heart-rate within short intervals was higher due to the more frequent occurrence of respiratory arrhythmias. It was also seen that during the music program the children showed no signs of exertion as they did towards the end of the didactic program. Respiratory arrhythmias were not seen in children who according to the Schellong-test were classified as stable in their cardiovascular system. The arrhythmias occurred mainly when the children showed signs of fatigue.     

Strain Localization Kinetics in a Metal Strip in Tension

Simulation results for strain localization in a metal strip are obtained with analytical and numerical methods. The initiation of strain localization is shown to be determined by the initial nonuniformity of material properties and by loading conditions. The more uniform material properties, the higher the strain level at which localized flow starts to develop. Metal heating under adiabatic deformation (as a result of the thermal plastic strain effect) causes a decrease in a strain level at which its localization starts. The pulse current passage, accounting for its thermal effect, exerts a similar influence. __________ Translated from Problemy Prochnosti, No. 5, pp. 104 – 117, September – October, 2005.     

Application of ion implantation for synthesis of copper nanoparticles in a zinc oxide matrix for obtaining new nonlinear optical materials

We have obtained a layered composite material by implantation of single crystal zinc oxide (ZnO) substrates with 160-keV Cu⁺ ions to a dose of 10¹⁶ or 10¹⁷ cm⁻². The composite was studied by linear optical absorption spectroscopy; the nonlinear optical characteristics were determined by means of Z-scanning at a laser radiation wavelength of 532 nm. The appearance of the optical plasmon resonance bands in the spectra indicated that ion implantation to the higher dose provides for the formation of copper nanoparticles in a subsurface layer of ZnO. The new nonlinear optical material comprising metal nanoparticles in a ZnO matrix exhibits the phenomenon of self-defocusing and possesses a high nonlinear absorption coefficient (β=2.07×10⁻³ cm/W).     

MBE of InGaN/GaN heterostructures using ammonia as a source of nitrogen

Technical Physics Letters - InGaN/GaN heterostructures have been grown by molecular beam epitaxy (MBE) using ammonia as a source of nitrogen. The influence of the growth temperature and rate on the...     

Generalized Deformation Curve for High-Strength Steel over a Wide Range of Strain Rates

Test results for different high-strength steel specimens in static and impact tension and compression over a wide range of strain rates were summarized. These data were used to calculate the generalized deformation curve. The calculations based on this curve were compared with the experimental data on impact indentation with the conical indenter to evaluate the applicability of this method for studying the behavior of metals at high strain rates.     

Producing a compact long-lived plasma formation

A method of producing compact long-lived plasma formations (plasmoids) is described. The method is based on the effect of capture of a high-current relativistic electron beam under conditions of significant overcompensation of space charge of the beam by positive background ions. Requirements are formulated which are placed on the parameters of a plasma-beam system for the realization of this method, and numerical estimates are given of the overall electric charge and energy content of the electron component of a plasmoid. The dynamics of forming a plasmoid are investigated experimentally.Translated from Teplofizika Vysokikh Temperatur, Vol. 42, No. 6, 2004, pp. 843–849.Original Russian Text Copyright © 2004 by B. V. Alekhin, A. E. Dubinov, V. S. Zhdanov, V. G Kornilov, K. E. Mikheev, V. D. Selemir, N. V. Stepanov, V. I. Chelpanov, and O. A. Shamro.     

Luminescence of CdSe quantum dots near a layer of silver nanoparticles ion-synthesized in sapphire

We study the characteristics of the luminescence of composite films based on polymethyl methacrylate with CdSe quantum dots deposited from solution onto the surface of a sapphire substrate containing a preliminarily formed layer with ion-synthesized silver nanoparticles. The sapphire layer with silver nanoparticles exhibits selective plasmon absorption in the visible spectral range with a peak at 463 nm. Enhancement in the exciton luminescence intensity of quantum dots with a peak at 590 nm is observed upon excitation at wavelengths lying in the region of plasmon resonance of metal nanoparticles, as well as luminescence quenching for quantum dots located in the vicinity of silver nanoparticles.     

The T-125/150-12.8 cogeneration steam turbine

The article presents the design, the economic indicators, and the main solutions on the thermal process circuit and layout of the T-125/150-12.8 turbine, a new design version of the T-100-12.8 turbine, which is one of the best known, unique and widely used cogeneration turbines in Russia and abroad. The project of the new turbine is supposed to be used both for renovating and upgrading already installed turbines of the T-100 family and for supplying it as a full set for replacing obsolete equipment or constructing new one.