Inverse magnetostatic problem for ferromagnets
Engineering Education # 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.
Measuring phase difference of quasi-harmonic signals in real time
Engineering Education # 07, July 2013
The authors propose a digital method of measuring the phase shift of quasi-harmonic signals with the same instantaneous frequency on a limited sample. A real-time algorithm was created on the basis of the specified method; the proposed algorithm was tested in numerical simulations and experiments at the developed hardware-software package. The measurement error of the phase difference of harmonic signals in the experiments did not exceed 10-6 rad while the measurement error of signals with amplitude modulation of 20% was less than 5 ∙ 10-5 rad. The method could be used to solve problems of radio interferometry, acoustics, etc., where the unknown value us expressed in terms of the phase difference of quasi-harmonic signals.
Interaction of mutually perpendicular magnetic fields in the type II superconductor
Engineering Education # 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
Engineering Education # 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 %.