A Radiofrequency–Optical Modulation Spectroscope for Investigating Semiconductor Structures

A radiofrequency –optical spectroscope that makes it possible to investigate the modulation optical reflectance spectra of the various layers of a semiconductor structure is proposed and manufactured. Near the edge of the fundamental optical absorption, the light reflectance is modulated by an RF field with various spatial orientations. By using the RF–optical modulation spectroscope, new features of the electron–hole interaction in the layers of a selectively doped GaAs/AlGaAs heterostructure are discovered and investigated.     

Method of calculation of parameters of wireless access channel for mobile terminals in millimeter wavelength band

It is proposed a number of new technical solutions to implement the delivery of multimedia signals 4G services with data transfer rate for each subscriber 6–12 Mb/s, which move at a speed of 300–350 km/h with a total capacity of the network over a thousand subscribers. The block diagram (architecture) of transfer network in the millimeter wavelength band is developed. We derived balance equation for the network radio energy, which is the basis of the method for calculating the radio channel parameters. Examples of calculation of radio wireless access parameters to mobile terminals in the millimeter range are presented.     

Testing mechanical properties of materials by indentation curves at different scale levels

Techniques and instruments for the determination of mechanical properties of materials by scratch and indentation curves are discussed. The capabilities and advantages of the indentation techniques at different scale levels of the deformed volume are shown. A new technique for the hardness determination by the indentation curve of a pyramid is proposed. The scope of application of the indentation techniques for testing mechanical properties of materials is determined.     

About numerical simulations of oil extraction process

We considered the problems of computational modeling of oilfield geological structure and simulations of oil extraction process. The paper describes the mathematical model of non-steady displacement of non-Newtonian oil by water in essentially inhomogeneous bed tapped by a system of injecting and operating wells. It presents the algorithms of numerical analysis of corresponding boundary-value problems. The features of the model have been keyed in user-friendly software. The capabilities of the software are illustrated through calculations of several typical problems of oil displacement by water.     

How to estimate the reliability of a weld joint under conditions of cyclic loading according to the results of a nondestructive check

The problem of how to determine the reliability of thin-walled structures as a function of the number of loading cycles and degree of inspection of the weld joints with blind cracklike holes, whose depth and length are independent random values, is solved. The reliability is characterized by the probability of whether the defect sizes belong to the admitted region, whose boundary is determined by the set of the initial sizes of the defects, which rises past the limit state of the predetermined number of loading cycles.     

Optimization of the Technological Synthesis of Refractory Compounds

The results of experimental studies, which are related to the regulation of the fractional composition of refractory compounds by roll milling in using controlled roll opening and unbalanced peripheral speeds of rollers, are reported. The content of prepared fine, middle, and coarse fractions is within 50–80%; in this case, the milling time of synthesis products is less than the time of ball milling by an order of magnitude. The application of roll milling for refining the products of self-propagating high-temperature synthesis can be most efficient in using together with heat-generating reactor to solve the main problem of self-propagating synthesis (SHS), which is a problem for recent several decades (the problem is the creation of intense automated production of refractory compounds in using continuous manufacturing cycle within a energotechnological system with the recovery of a great quantity of heat released during SHS).