Non-contact non-destructive laser-interferometric methods for measuring several electrophysical parameters of semiconductor and dielectric layers are proposed. They are the lifetime of charge carriers for electrons and holes separately; parameters of recombination centers, namely their concentration and capture cross-sections; bulk volume lifetime and rate of surface recombination, as well as the diffusion length of charge carriers. The methods are based on the interference-absorption interaction in a semiconductor of two laser radiations with different wavelengths. Short-wave injection radiation generates additional charge carriers in the material, which leads to a change in its optical constants at the wavelength of the other – long-wavelength probing laser radiation – and to modulation of this radiation as it passes through the sample of the studied material. The means for implementing the proposed methods and methods for processing the modulation signal for determining the parameters of the investigated samples are developed. The methods have been successfully tested on samples of such materials as germanium, silicon, indium antimonide and cadmium-mercury-tellurium alloy. It is shown that the methods can be used both in scientific research and electronic industry.
In clause the urgency of transition from traditional gauges of electric drives of a dredge to nogauge is shown to the observer of the basic coordinates, the mathematical model of the adaptive observer for a drive of rise of a dredge is proved and created.
For diagnosing transmission of the mountain machine without installation of expensive gauges pilot diagnostics on parameters of a feed of the electric motor, based on the assumption can be used, that the majority of the indignations arising in transmission and influencing at the moment of resistance, overcome by the engine, affects change of instant power consumed by the electric motor.
The paper demonstrates the necessity to introduce efficient adjustable electric drives for inter-floor moving ramps; a mathematical model has been created for an automatic drive control system and a mathematical model of the adaptive observer for the ramp drive has been justified and created.
Wind is one of the most important alternative sources of energy, the distinguishing features of which are zero cost and no negative impact on the environmental situation. In view of the increasingly worsening fuel and energy crisis, interest in the use of wind energy has increased significantly over the past few years. Data on the structure of a wind power plant are given. Asynchronous machine with squirrel cage rotor is considered as a generator. A model of an autonomous induction generator is constructed taking into account the nonlinearity of the magnetic circuit. The model for automatic construction of mechanical characteristic of asynchronous machine is also presented. Modeling is performed in the MatLab Simulink environment.
The article considers alternative possibilities of controlling electric drives of oil pumping units with the help of intelligent neural networks, models of traditional and modern sensorless coordinate observer, their comparison is carried out.
The Russian Federation is one of the largest miners and exporters of natural resources worldwide. The mineral reserves at the bottom of the world's oceans are many times greater than those on land, which makes it necessary to develop fundamentally new equipment for their extraction. One of the most interesting solutions to this problem is a double-supported walking machine. The issues devoted to the development of the structure and algorithm of controlling the motion of the walking machine for mining minerals from the seabed are considered. A mathematical model of the electromechanical drive for turning the chassis during stepping is proposed, technical requirements to the electromechanical drives of the machine are stated and the control algorithm of the non-contact electric drive is described.
