Two-layer nonreflective absorber of electromagnetic radiation

Conditions for reflectionless quenching of electromagnetic radiation in the layer of absorbing dielectric applied to a nonabsorptive quarter-wave substrate have been found. These conditions as functions of the layer thickness and the dielectric properties of the coating and the substrate are investigated.     

Experimental studies of water temperature regime in trough solar collectors

Results are presented of comparative studies of water heating in large trough solar collectors with protected and open evaporation surfaces.     

Measurement of the magnetic properties of liquid magnetic materials at microwave frequencies

Equations are obtained which give a unique functional relation between the required magnetic properties of a liquid magnetic material and the informative parameters on the position and value of the extrema of the experimental dependence of the reflected signal on the thickness of the layer of material. Various methods and algorithms for solving them are considered, taking the degree of attenuation of the wave in the material into account. __________ Translated from Izmeritel’naya Tekhnika, No. 4, pp. 47–49, April, 2007.     

The mechanisms of the emotiogenic regulation of memory

The determining mechanism of memory regulation is a system involving the right temporal region and two anterior frontal regions. This is a cortical part of the integral system of the emotional regulation of memory. The dopaminergic mechanism forms the basis for fortifying the emotiogenic memory system, promoting the facilitation of retrieval. The selective emotional set of aggressive and submissive mice determines both the processes of extinction, development of amnesia, and subsequent reactivation of a memory trace induced by neuropharmacological agents. The GABA system is shown to enter the mechanism that controls the activity of dopamine system--dopamine release from the terminals of the nigrostriatal and mesolimbic dopaminergic systems is stimulated. The neurochemical background in the development of amnesia or forgetting determines the subsequent retrieval of a memory trace. The dopamine and GABA systems are common links in the retrieval of amnestic and forgetting memory traces, respectively. A substantial rise of met-enkephaline levels along with the maximum increase of D2-receptor density in the frontal cortex, amygdala, striatum, and hippocampus were observed in rats after learning. In vitro experiments indicated that met-enkephaline and beta-endorphine stabilized the kinetics of dopamine-receptor interactions.     

Limiting sensitivity of location probing of power transmission lines while detecting ice coatings

Ice coatings on power transmission lines (PTSs) are detected during location probing from the amplitude reduction and the increase of propagation (delay) time of the reflected signals. The stability of the amplitude and delay of the reflected signals in the normal conditions in the absence of glaze ice and the limiting sensitivity of the method of location are studied in the article. As a result of long-term measurements on operating power transmission lines, the daily–annual variation of amplitude U and delay Δτ of the reflected signals were detected due to the high sensitivity of the method of location, which is mainly due to variations in environmental temperature. It was shown that these variations, combined with the random fluctuations,in normal conditions are much smaller than the changes of the amplitude and delay of signals upon early appearance of ice coatings. The recommendations on selection of the values of settings (operating threshold) are given by the amplitude and delay upon detection of the glaze ice and damage to the power transmission lines by the method of location.