The results of modelling of wire antenna with fractal configuration of radiating elements are presented. For analysis the fractional differintegration calculus is used. Antenna diagrams depending on index of fractality of consisting vibrators are compared. INTRODUCTIONThe necessity of perfection of mobil communication makes it actual designing and studying of properties of nonsymmetrical antennas with very little electrical length of vertical parts of vibrators. It is interesting to use inhomogenious artificial mediums with vertical and inclined vibrator elements placed near to each other and weakly radiate because of odd currents. Antennas with such properties my be realised on the base of designing of fractal radiating elements. As a result of covering of fractal part of vibrator by regular compacts the problem of analysis is reduced to construction of the Housdorffs smoothing measure on the physically prefractal layer with differintegration of equilibrational current density over the projection of fractal set on smooth segment. Proceeding from the fractal representations about the current structure in a conductor and the field induced in an artificial metal-dielectric medium, using of the concept of fractional differintegration calculus the proved fact [l] is used in this paper that the behaviour of the field component u(r) in the medium with fractal properties of conductivity, permittivity etc. may be described by fractional integrodifferential (acharacteristic):
Background. Under the influence of combined interference, the effectiveness of radar performance significantly deteriorates. This is preconditioned by decorrelation of active noise interference by passive one that has a spatially distributed spectrum. To reduce the influence of passive interference on the active interference compensation process, it is necessary in one way or another to form a classified training sample generated only by the active interference and to assess the possible losses that arise with this case. Objective. The aim of the paper is to estimate losses for the case of adaptive spatial filtering of the active component of combined interference in the frequency method of generating a classified training sample. Methods. Analytical method of losses estimation simultaneously with the method of simulation. Results. The estimation of losses in compensation of active interference arising for different values of the base and the width of the interference spectrum coming from different angular directions has been made. The losses have been estimated which were preconditioned with introduction of notch filters in the chain for forming the weight factor of the autocompensator are estimated. Conclusions. The scientific novelty is the possibility to estimate the losses in active interference compensation in spatial signal filtering using the frequency method of classified training sample generation. The practical significance is to provide the possibility to choose parameters of the jamming system when designing the radar.
The deformability of refractory brickwork differs sharply from the deformability of the refractory parts themselves. Brickwork of refractory blocks or bricks with mortar or without it is a complex mechanical system the elements of which contain a multitude of defects unknown in advance (roughness, nonuniformities, projections, etc.) and therefore have a statistical nature.Laboratory investigations of the mechanical properties of brickwork based on tests of small samples (composite of the periodic element--layer-element--..."structure") in isothermal loading are basically made difficult for reasons related to the scale effect. Under actual service conditions the brickwork is subject to the action of high temperatures. For given materials at certain specific temperatures a "sintering" effect is observed, as the result of which the brickwork becomes almost monolithic but the properties of the joints and the blocks are individual. Therefore an experimental method in which the interaction and influence of the above factors would be taken into consideration integrally is the most reliable for studying the properties of brickwork,* To conduct the experiments in compression and tension of an element (packet) of the brickwork in heating to 1500~ the Institute of Mechanics of Moscow State University together with the Ukrainian Scientific-Research Institute for Refractories designed and built a test stand in the Experimental Plant of the Ukrainian Scientific-Research Institute for refractories, Using the test method developed, a sample packet with a mortar binder of 10-12 bricks (cross-sectional area F) was assembled on a special car in front of the kiln passage or in the kiln, The thickness of the Joints was measured with a thickness gauge. The car was rolled into the kiln and the packet was placed on the cylindrical rollers of the support ceramic plate and then dried in the kiln for 24 h, after which the kiln was turned off. On the two end sides of the sample was placed a measuring system with a dial indicator. The difference A~ in the indicator readings was the change in packet length as a whole. In the horizontal position the sample was loaded with an axial force. The total axial compressive force P, determined with a dynamometer~ reached 49 kN. The accuracy in measuring the deformation was • A packet of type MKV-72 mullite--corundum refractories (GOST 20901-75) for the brickwork of the walls of hot blast stoves was tested. The 345•215 mm parts were produced by Zaporozhe Refractory Plant. VT-I mortar was used in laying the packet. The firing temperature of the packets was:
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