PORTABLE SEISMIC SYSTEMS (OVERVIEW)

The review presents a survey of the current state of development of portable (transportable) guard and reconnaissance-signaling seismic systems. The features of application and advantages of such systems over stationary are shown, the general trends in the design of the portable guard and reconnaissance-signaling systems are to described. Their main design features and characteristics serially produced for civilian and military use are given.

FORMATION OF THE OBJECT IDENTIFICATION ZONE WITH LASER INFORMATION-MEASURING SYSTEMS AT SHORT DISTANCES

The optimization of the methods for the formation of the spatial-energy distribution of the probing radiation power and the processing the receiving signal by the locating laser information-measuring systems (LIMS), taking into account the spatial-temporal structure, is carried out, and the analysis of the existing methods of their processing is carried out too. An assessment of the integral criteria for the LIMS functioning when operating in conditions of interference has been made. The calculation of the parameters of the LIMS main links was carried out, taking into account the correlation between the resolution of the optical system and the capabilities of object detection, recognition and classification. A method was developed for the formation of the probing radiation density distribution and the receiving signal processing, taking into account its space-time structure, which made it possible to determine the optimal duration of the laser probe pulse. The determined duration makes it possible to eliminate errors in measuring the parameters of an object's movement under the influence of a combination of destabilizing factors and a lack of signal processing time, which will ensure the accuracy of the target detection and recognition.

METHOD OF EXCITATION OF QUASI LONGITUDINAL ACOUSTIC WAVES IN LAYERED STRUCTURES

The analysis of methodological possibilities of excitation of quasi-longitudinal (QL) acoustic waves of the megahertz frequency range in layered structures GaN-on-sapphire is studied and carried out. Volume-type transducers polarized by plate thickness are used to generate and detect QL waves. It is concluded that quasilongitudinal modes (QL) can be excited by this method – the so-called Anisimkin (AN) waves, for which the displacement plane is localized in the film plane and the displacement direction is directed along the wave vector.

ADAPTATION OF THE PROCEDURE OF CO-IMMOBILIZATION OF ENZYMES WITH DIFFERENT MODIFICATIONS OF ZEOLITES ON THE SURFACE OF CONDUCTOMETRIC TRANSDUCERS

A comparative study of different parameters of conductometric biosensors based on urease and glucose oxidase, co-immobilized with different types of zeolites. Urease immobilized on silicalite-2 was shown to have better performance than immobilized urease without zeolites. Conductometric biosensor with glucose oxidase co-immobilized with zeolite NH4+-Beta 25 had similar response values compared to immobilized enzyme without zeolite. Immobilization of zeolites NH4+-BEA 30 and H+-BEA 30 together with urease leads to an increase in the response of the biosensor, while the reproducibility of the signal remains unchanged. Biosensors with zeolites with a higher Si/Al ratio were characterized by increased signals. The use of zeolites modified with methylviologen and silver did not give a positive effect.

DEVELOPMENT OF AN ENZYME BIOSENSOR BASED ON pH-SENSITIVE FIELD-EFFECT TRANSISTORS FOR ESTIMATING THE TOTAL CONTENT OF INDOLE ALKALOIDS IN TISSUE CULTURE OF RAUWOLFIA SERPENTINA BENTH. EX KURZ

A laboratory prototype of an enzyme biosensor based on pH‑sensitive field-effect transistors has been developed to determine the total content of indole alkaloids in Rauwolfia serpentina Benth. Ex Kurz tissue culture. The biosensor was characterized by high sensitivity to th A laboratory prototype of an enzyme biosensor based on pH‑sensitive field effect transistors has been developed to determine the total content of indole alkaloids in Rauwolfia serpentina Benth. Ex Kurz tissue culture. The biosensor was characterized by high sensitivity to the total content of indole alkaloids (minimum limit of determination – 0.5 μg/ml of the total content of indole alkaloids contained in the juice obtained from tissue culture of Rauwolfia serpentina). The linear range of biosensor determination of the analyte was from 2 to 15 μg / ml of the total content of indole alkaloids. Analysis of indole alkaloids using a biosensor is simple and fast and does not require expensive equipment and special sample preparation for analysis, unlike traditional methods. The created biosensor can be further used to control the total content of indole alkaloids in modern biotechnological and pharmaceutical processes for the production of drugs and biologically active additives. e total content of indole alkaloids (minimum limit of determination – 0.5 μg/ml of the total content of indole alkaloids contained in the juice obtained from tissue culture of Rauwolfia serpentina). The linear range of biosensor determination of the analyte was from 2 to 15 μg / ml of the total content of indole alkaloids. Analysis of indole alkaloids using a biosensor is simple and fast and does not require expensive equipment and special sample preparation for analysis, unlike traditional methods. The created biosensor can be further used to control the total content of indole alkaloids in modern biotechnological and pharmaceutical processes for the production of drugs and biologically active additives.

DEPENDENCE OF MAXIMAL SENSITIVITY OF THE MAGNETIC FIELD HALL SENSORS BASED ON GRAPHENE ON TEMPERATURE

A theory of graphene-based magnetic field Hall sensors sensitivity dependence on temperature is summarized. The existence of low-temperature range with sensitivity, almost independent on temperature, is predicted; at higher temperatures, when thermally-induced carrier concentration in graphene prevails, the sensitivity decreases with temperature. The experimental studies of the temperature dependence of magnetic sensitivity of Hall sensors on single layer graphene base were carried in temperature range from 300 °K to 430 °K. The values of sensitivity, obtained for room temperatures ~ 230 V·А‑1·Т‑1 exceed essentially the maximum sensitivity of the traditional Hall sensors on silicon base ~ 100 V·А‑1·Т‑1.

METHOD OF EXPANDING THE DYNAMIC RANGE OF MEASURING SIGNALS OPTICAL LOCATORS

A method for broadening the dynamic range of signals in optical locators of a portable complex has been developed, which allows increasing sensitivity and perform effective spatial and spectral selection of signals against noise, what affects the quality of the detecting and tracking aerodynamic objects task. An assessment of the possibility of object detecting in different interference situations, i.e. the selection of the target signal from noise, background or internal, depending on the method of signal processing.

PHYSICS OF MOSFET NANOTRANSISTORS: FUNDAMENTAL LIMITS AND RESTRICTIONS

In the last one from the series of the tutorial review articles, devoted to physics of modern nanotransistors and aimed to serve reseachers, ingeneers, students and teachers in the universities, it is demonstrated that the existence of the minimal energy for recording of 1 bite of information leads to fundamental restriction on minimal MOSFET channel length and on minimal time of transistor swithching. The obtained simple estimation Lmin = 1.2 nm (for room temperature) is somewhat lower, than in reality, and it looks like that Si FETs with a channel shorter than 2.5–3 nm would newer be fabricated. This correlates with the results of numerical modeling of electron transport through the channel, which demonstrate that for short channels the greater part of current passes by tunneling below the barrier top, and the transistor loses its functionality, because the current in source-drain circuit is no longer governed by gate voltage.

SENSORY FEATURES OF TIACALIXARENE FILMS TOWARDS TOXIC AND EXPLOSIVE VOLETILE COMPOUNDS

The work is dedicated to the investigation of adsorption features of functionalized derivatives of tiacalix[4]arenes towards phosphorus and chlorine organic volatile compound as well as well as to nitroaromatic simulators of explosive organic compounds. Experiments were carried out with quartz resonators array covered with the films of calixarene receptors. Experiments were performed at the concentration levels 10–1000 ppm, that corresponds to 100–10 dilution of the saturated vapours of analytes. Detection limits reached 10–100 ppm depending on the type of analyzed toxic substances; operational speed was about 10–20 sec.