With the use of pulsed laser deposition and carbothermal synthesis а photosensitive structure on the basis of the Schottky barrier Au/ZnO(nanorods)/ZnO(film)/ZnO(nanorods)/Au was obtained. The parameters of the carbothermal method of synthesis of nanorods ZnO were optimized. Under directly applied bias of 7V current sensitivity of luminous flux for this photodetector is observed in the UV and visible regions of the spectrum, and is 0.14 A/W - for 325 nm and 0.18 A/W - to 405 nm, which means that this structure has the ability of potential applications in various fields for the control of UV radiation (for example, for the monitoring of solar UV radiation, control of UV radiation in air and disinfecting water devices).
Keywords: ZnO nanorods, Schottky barrier, photodetector, photosensitivity
ZnO nanorod arrays have been synthesized on silicon wafers by chemical vapor deposition (CVD) technique with different temperature modes, without metal catalyst. With this method vertically aligned ZnO nanostructures were grown at the quite low temperatures. Modification of the method allowed to place silicon substrates in areas with different ratios of concentrations of the molecules in the vapor phase. Photoluminescence spectroscopy and electron microscopy studies have shown that morphologies and optical properties of nanorods depends on different ratios of concentrations of the molecules in the vapor phase.
Keywords: ZnO nanorods,chemical vapor deposition (CVD), photoluminescence
The arrays of ZnO nanorods were obtained on the sapphire substrates by means of pulsed laser deposition under the high pressure of argon. The conditions of synthesis were optimized, and their influence on the morphology of ZnO nanostructures were revealed. It is shown that the concentration of oxygen vacancies in ZnO nanorods can be changed by regulation of the synthesis temperature from 850 to 915 °. This process can be controlled by the ratio of intensities of the photoluminescence emission in the visible and ultraviolet regions. So, it allows to create nanostructures for UV photodetectors or chemosensors depending on the temperature choice.
Keywords: ZnO nanorods, laser deposition, PLD, photoluminescence
This paper outlines the implementation of computer model of second-order visual mechanisms that are specific to spatial contrast modulations, and represents the results of testing the model. Computer simulation is based on "Filter-Rectify-Filter" model with some important additions. The inhibitory parts of receptive field of simulated mechanism are non-selective to orientation and spatial frequency of texture elements. Texture modulated by orientation or spatial frequency does not reduce flank inhibition and does not activate the mechanism. Unmodulated texture also does not cause activation of the filter because the flanking inhibition will be equal to or exceed the excitation. However, increasing the contrast in the center and reduction it on the flanks leads to the activation of the second order mechanism.
Keywords: Second order visual mechanisms, image filtering, texture, spatial modulation, computer simulation
The work is devoted to the study of algorithms of control subsystem as part of the integrated onboard control system of the aircraft and used in the final part of the trajectory. Algorithms of control subsystems are synthesized on the basis of the theory of optimized delta-transformations of the second order using the principle of the inverted pendulum on a cart. The studies based on the simulation using the developed software model, allowed to estimate as the impact dispersion, and the contribution to it of various subsystems.
Keywords: terminal control, aircraft, on-board integrated control system, optimized delta transformation of the second order, autonomous short range radionavigation system, simulation, software model
In this paper the technology of repair of ground water retaining structures soil mixture improved quality with and without soil mixture install.Use soil mixture , improved sharps and ensure the return of ashes (repaired ) slopes and ridge structures of high strength (up to 13-15 MPa) and water resistance , thus increasing the effectiveness and quality of the repair work and increased resistance to the elements of the structures induced defect . The presence of the bran soil mixture not only enhances the strength of 30-40% , but also gives a significant increase in water and frost (20-30 %), which prevent or substantially reduce the infiltration of water through the filtration body water retaining structures , since high strength and frost soil-concrete being laid on a slope ( in the recovery slope failure ) and groove (at soil dumping and capacity to or in excess of the design marks ) will reliably protect the body of the dams ( dams ) of the drawdown , erosion , buckling , suffusion , and other deformities.
Keywords: technology, dribble feed , soil mixture, sift, cement, fly ash, dam, construction and repair operations, soil mixture installation, factors plan of the experiment, the regression equation
In the article authors examine specificities of internal components behavior changing in fiber-optical cable under influence of strong variable uniform electromagnetic field. There are some process variations proposed for describing of obtained results.
Keywords: fiber-optical cable, electrothermal degradation, kevlar, conductivity, open fiber-optical cable, partial discharges, water treeing
The article describes peculiarities of modern syntax parser systems and problems originating in text analysis. As a result of comparative analysis the authors propose a unified approach to processing of unstructured texts in Russian and English which combines morphology and syntax processing. The developed syntax analysis system, using verbs’ valency dictionary, samples of minimal structural schemes of sentences and samples of conjunctions, allows choosing predicative structures of sentences in the text, realizing initial semantic analysis due to semantic content of predicate’s actants and building trees of syntactical subordination of sentences. The derived trees hold elements of tree of constitutives and tree of dependences. The proposed samples and rules organization allows resolving some of the problems of modern parsers. And the use of verbs’ valency dictionary allows reducing the number of sentences syntax analysis variants.
Keywords: automatic text processing; syntax parser; morphological analysis; structural text elements
In this work experimentally investigated the possibilities of the new method of obtaining adjustable roughness on metal surfaces electrothermal influence of mobile cathode spots in vacuum arc discharge. Presents the results of processing of various surfaces using this method. Proposed working modes of processing of metal surfaces with the aim to receive as minimum and maximum roughness.
Keywords: roughness of metal surfaces, vacuum arc discharge, cathodic spots
In the present work proposes a specified description of potential functions when the free spreading in the two-dimensional turbulent flow of planning. In contrast to previous decisions, new parameter satisfies the continuity of flow when the flow flowing from rectangular tubes on the discharging track
Keywords: final line of motion, lines of equal potential, horizontal rectangular tube, diverting from the mainstream flow
In this paper is offered hydraulic sensor to measure the kinematic, power and energy parameters. Developed scheme and the principles of the hydraulic sensor. Identification on the special flow lab with real modes of the device is determined by its performance in different conditions. Approximation of the results received dependences flow and pressure drop characteristics on the speed and entrance pressure, allowed more correctly assess and describe the operation of the hydraulic sensor over the entire range of speed and entrance pressure.
Keywords: hydraulic sensor, spilling method, flow and pressure drop characteristics, multifunction control unit.
An analysis of the problem of increasing the efficiency of the functioning of the logging trucks for hauling timber to the lower timber depots and consumers. Proposed technical solutions for of raising cross-trains in complex natural and industrial environments.
Keywords: Active semi-trailer used forestry, passableness, prosary operation.
The temperature dependencies of the main parameters of p-channel MOSFET model in a temperature range 20 ... 300 K are measured. The universal formal four-parametric model, which allows approximating all experimental temperature dependencies with the relative error less than 1 % is proposed. The model is intended for the MOSFETs which are applying in low-noise amplifiers of the radio-receiving devices of an optical and infrared range on astronomical satellites, radio telescopes and space observatories. The presented results can be used to simulate the temperature modes of MOSFET amplifiers in SPICE-type electronic simulators. The solution of this problem will predict uptime device when the temperature changes in the cases of emergency or extraordinary situations and also will allow optimizing the choice of refrigerant and increasing the reliability of the amplifier in the conditions of cryogenic temperatures.
Keywords: MOSFET, MOSFET parameters, cryogenic temperature, parameters measurement, temperature dependencies
The problem of efficient use of lubricants in service of railway technology, based on a system for the collection of used oil and re-use them after regeneration. The analysis of the consumption of lubricants and identify possible potential resource - the volume of used oil and the resulting volume of recovered oil.
Keywords: oils, operation of transport equipment, used oil, used oil collection, regeneration
The method of digital parametric measurement of the phase shift of signals with slowly varying amplitudes of the same slowly varying instantaneous frequencies was proposed. The numerical simulations and experiments on the developed hardware and software system were carried out. The error of measurement the phase difference of harmonic signals in the experiments were not more than 0,00001 radian. The method can be used in applications where the measured value is expressed in terms of the phase difference of quasi-harmonic signals.
Keywords: quasi-harmonic signal, phase shift, real time measurements, hardware and software system