scientific edition of Bauman MSTU
SCIENCE & EDUCATION
Bauman Moscow State Technical University. El № FS 77 - 48211. ISSN 1994-0408
Simulation of Recording the Microwave Holograms of Complex Objects by the Near Range Radars
# 06, June 2014
This investigation goal is to develop a computer simulation method to record the microwave holograms of complex objects by the near range radars. The surface of the created object is described by a set of triangular facets. While calculating the reflected field, representation of the object as a set of point reflectors is used. Thus, the model of unitary dispersion is used, which does not consider re-reflection and cross influence of reflectors. Methods for forming a focused image of the object reflectivity function from microwave hologram are described. The model can be used at the early designing stages of the near range radars.
Inverse magnetostatic problem for ferromagnets
# 01, January 2014
УДК: 537.62, 620.1
We consider the problem of multi-parameter analysis of the magnetic microtopology to determine the structure of the material and finding defects. We propose a method for the analysis of raw data by dividing the obtained information on a priori criteria, determined by the physical model of a ferromagnet. We show the integral connection between the slowly varying magnetization and the stray field with tensor system functions. We calculate limits of heterogeneity of the magnetization and the external field. The analysis of experimental data for magnetic microtopology steel flat specimens with artificially created defect. The above approach to magnetostatic problem can be used in the microarray analysis and inspection.
Simulation of absorption and dispersion processes of electromagnetic waves within the microwave frequency range in dispersed media based on wave optics
# 09, September 2013
This paper describes the interaction of artificial disperse systems with electromagnetic radiation within the microwave frequency range, which is based on the conditional division into sub-bands according to the character of interaction. For one of the sub-bands, a mathematical model was proposed that in the approximation of wave optics allows one to calculate the reflection and absorption characteristics of the system. Results of the calculations were also presented. A possibility of creating a dispersed system operating within the frequency range from 1 GHz (30 cm) up to 120 GHz (2.5 mm) was demonstrated. Moreover, its sizes (14 m) are comparable to the size of an object of military equipment, and the mass of the dispersed phase is only 3.7 kg.
Accuracy evaluation of modern computer programs for calculating objects’ effective echoing area
# 09, September 2013
A problem of computational accuracy of objects’ effective echoing area (EEA) using modern software such as CST Microwave Studio and «Analysis of radiolocation characteristics of complex shaped objects» developed in Bauman Moscow State University was considered. The authors tried to formalize accuracy evaluation procedure for these programs using characterization factors and mean-root-square errors between monostatic angle diagrams of EEA for some objects obtained with a use of the specified software and ones, experimentally measured. It was shown, that software had acceptable accuracy of ±5m2.
Controlling the abrasive finishing process
# 04, April 2013
The author considers factors of abrasive finishing of details at finishing machines by a loose abrasive; these factors determine the output of the process. It was noted that the physical basis of abrasive finishing is an abrasive destruction of the detail material and lap material which is the result of the influence of forces occurring during machining; however, the majority of factors are not power ones but they do influence the result of machining. A new characteristic of the abrasive finishing process was proposed; this is a spectrum of the force influencing the surface element of a detail. This parameter allowed to unite all basic technological, kinematical and dynamical factors of the abrasive finishing process into a single power characteristic. This will lead to simplification of the control system and increase its efficiency.
Study of structural properties of high-performance radio-protective materials
# 10, October 2012
In this work the object of the study is composites based on ultrahigh molecular weight polyethylene (UHMWPE) filled with nano-size particles of tungsten and boron carbide. The aim is to study structural properties of composite materials based on the polymer matrix UHMWPE. The field of application of composite materials based on UHMWPE and reinforced by nano-particles of tungsten and boron carbide is: materials for radiation protection capable of operating in a complex radiation environment with the ability to absorb both gamma and neutron radiation.
Interaction of mutually perpendicular magnetic fields in the type II superconductor
# 11, November 2012
The problem of interaction of crossed magnetic fields in the superconductors is considered. The expression which connects values of longitudinal and cross components of a magnetic field was obtained. The possibility of using this effect for measuring a magnetic field is shown; assessment of sensitivity of such a magnetometer was carried out.
System function of magnetoactive element in inhomogeneous magnetic field
# 10, October 2012
The authors propose a method of calculating a system function of a magnetoactive element in the linear approximation. The authors carried out numerical calculations for the galvanomagnetic element of type PHE602817A and experimental verification of the relations of reciprocity in an inhomogeneous magnetic field. They demonstrates the ratio of reciprocity with an accuracy of 2 %.
Description of electromagnetic waves in a vacuum with the usage of physical quantities - polarization and magnetization
# 06, June 2012
Wave equations are usually differential relations between electromagnetic field quantities. However, there is a possibility of description of electromagnetic waves even in a vacuum with the use of material quantities of polarization and magnetization. A model of electromagnetic waves can be created using these physical quantities. The author’s system of physical quantities and laws was used for demonstrative description of wave and other relationships of electromagnetism.