Effect of modifying additions on the ductility and plastic properties and the brittle strength of cold‐resistant,low‐alloy steel

The special features of contact-reactive soldering of crystals to the bodies of devices are investigated. The methods of soldering crystals to the bodies of power semiconductor devices with the formation of the Si–Au, Al–Zn, and Zn–Sn eutectics are analysed. New methods of lead-free contact-reactive soldering of crystals with the formation of Si–Au, Al–Zn, Zn–Sn, and Al–Zn–Sn eutectics were developed and tested.     

Mathematical model of the mechanism of resistance of welded joints in oil and gas pipelines to static hydrogen fatigue

The problems of increasing the quality of resistance spot welded joints in transformation-induced-plasticity steel are investigated. Special attention is given to the effect of the heat treatment pulse and its parameters. The efficiency of application of an additional heating pulse for increasing the ductility of the welded joints is confirmed.     

Intrinsic noise variation in an amplifier based on a heterojunction bipolar transistor amplifier in nonlinear mode

Intrinsic noise variation in a heterojunction bipolar transistor amplifier with intense interference at its input was analyzed using the Volterra series method. During the analysis, the nonlinearity of correlated sources of collector and base noise currents was considered. It was shown that the change in noise at the amplifier output caused by interference depends on both nonlinear properties of the transistor and its dc operation mode, as well as the ratio of the levels of all its intrinsic noise sources.     

Conditions for SHS of intermetallic compounds with selective laser sintering of powdered compositions

The selective laser sintering of powdered mixtures traditionally used in high-temperature synthesis technology is studied. It is shown that a controlled exothermic combustion reaction can be set up in the focal spot of a CW Nd-YAG laser. The required laser interaction parameters (power, scan rate, and laser beam diameter) and dispersity and composition of the powder composition are determined for this mode of preparing three dimensional samples of intermetallic compounds by selective laser sintering. Translated fromFizika Goreniya i Vzryva, Vol. 35, No. 2, pp. 59–64, Mach–April 1999.     

Simulation of Curing Process for Propargyl Terminated Novolac Resins

Non-isothermal kinetic simulation analysis was carried for CFRP （carbon fiber reinforced plastic） based on PN （propargylated novolac） resins with various curing enthalpy. The simulation study was performed for CFRP with 40% mass resin content. It was shown that, curing enthalpy of PN resin must be less than 600 J/g to avoid uncontrolled heat emission causing destruction of composite sample.     

Fluorescent express-method for monitoring of oil condition in tribosystems

Current interest in evaluating the oil condition in tribosystems is discussed. Fluorescent express-methods for oil condition monitoring are analyzed and their main advantages and disadvantages are noted. The basic concept of the fluorescent method developed for evaluating oil oxidation rate by recording the shift of fluorescence spectrum to the long-wave region is described. The realization of the method is exemplified and the results of the analysis of fresh and worked hydraulic oils with the developed fluorescent sensor are given. The sensor can be used as both built in the oil line and a portable device under manufacture and laboratory conditions.