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 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
A mathematical model of a surface mini-ship "Neptune", including a mathematical model of the actuators. Used to identify the parameters of the mathematical model. analysis of stability and controllability of surface mini-vehicle for its mathematical model.
Keywords: mathematical model, surface mini-ship, handling, stability
In this paper a systematic study of individual single-walled and multi-walled carbon nanotubes was performed by Raman spectroscopy and high-resolution electron microscopy. We have presented the geometrical and electronic structure analysis on the examples of two tubes: individual single-walled and double-walled nanotubes. The role of different environmental effects and their influence on the final structure assignment are discussed. Moreover, we have shown that the Raman spectroscopy gives reliable estimations of the nanotube diameters and the conductivity. Given a non-destructible character of Raman spectroscopy, we may conclude that it is one of the most efficient methods for structure analysis of carbon nanotubes.
Keywords: Carbon nanotubes, Raman spectroscopy, electron microscopy
Proposed by parallel implementation structures aloritmicheskih simulating year-round circulation of water bodies. The research evaluation of computation time, find the optimal algorithm for the implementation of independent calculations for multi-core processors to reduce the computation time.
Keywords: parallelization of computations, thermohydrodynamics modeling of water objects, multi-core processors
This article describes the model of the pseudorandom sequences (PRS) generator developed in OrCAD program suite.The described model is applicable for radio systems modules circuits simulation that are using in the operation a PRS. The PRS generator implementation in OrCAD make possible to change PRS parametres immediately in the program, without using other software. A model specificity is that it is parametrised. Parametrization facilitates model control and that is reduce to a minimum necessary manipulations for changing of PRS type. The model is constructed on the basis of circuitry implementation of the linear feedback shift register (LFSR). For adjustment of model it is enough to instal code words setting starting state a LFSR, parametres of a signal of a clock source and to specify register tap output. As an example, used a 16-bit LFSR to create maximum length PRS, tap sequence {0, 5, 9, 13}. Emulation results are presented.
Keywords: pseudorandom sequence, PRS generator, LFSR, OrCAD, circuit simulation
In modern conditions, of particular importance is the need to form a model of the reproductive system of the regional economy, adequate objectively existing level of technological development, trends involvement in every phase of the reproductive process of innovative products, intellectualization of human activity, as well as the new requirements of economic globalization of world economic relations. In this regard, there is a need for a management model reproductive potential, focused on the balanced development of all the subsystems of the regional economy, taking into account the factors of integration and globalization of the world economy.
Keywords: balance, reproductive potential, production function, the economy of the region
In the paper we consider the energy efficiency of electric trains in overcoming the curved portion of the profile path. In this paper, were synthesized motion control algorithms that will help conserve energy resources by means of changes in traffic patterns electric depending on the profile path. The simulation electrorolling stock motion by offer the model showed a reduction in energy consumption compared to the nominal operation.
Keywords: energy efficiency, electric train, traffic management, motion control algorithms, reducing the consumption of energy resources
Article represents the analysis of activity of management companies in the market of housing-and-municipal services of Rostov-on-Don for definition of structure of the market and development of offers on its improvement on the basis of mechanisms of management, such as standards of housing and communal services, the public-private partnership, coordination of interests of business, administration and owners of housing stock.
Keywords: Management company, housing-and-municipal services, housing and communal services, public-private partnership.
We prove the prospect of using the territory of the Republic of Karelia for the production of the pilot project "Karelian bioenergy cluster", to reduce dependence on imported thousands of miles away-facing expensive fossil fuels and to improve their socio-economic situation due to the involvement in the processing of native species in -renewable resources.
Keywords: bioenergy, wood, potential, Republic of Karelia, the peat
Chlorination is the most common, and in fact no alternative method of disinfection using in Baghdad water supply system. Thus there is an urgent need to control the trihalomethanes (THMs) in drinking water. One of the objectives of this study is to investigate the content of THMs in Baghdad water supply network. Studies showed that the substantial amount of THMs formed in water distribution system, THMs content tends to increase with the distance from the starting point coupled with a decrease of residual chlorine concentration. It is observed that in summer total THMs concentration growth rate in water supply network was 1.3-1.4 times higher than in winter as well as total amount of THMs increase by 30 percent in summer. It was found that the concentration of total THMs never exceeded 80 μg/l – the level specified in National Primary Drinking Water Regulations: Disinfectants and Disinfection Byproducts (Stage 1) established by USEPA. However, in summer total THMs concentration in the water always exceeded 40 μg/l – the level set in accordance with Stage 2 of this Rule. The most of total THMs (73-80%) were bromine compounds (CHCl2Br, CHClBr2 and CHBr3). It is shown that the most efficient way to reduce THMs in Baghdad water supply network is to use the chlorine dioxide for chlorination.
Keywords: chlorine dioxide, chlorination, drinking water, trihalomethanes (THM), water supply network, water supply system
The process of constructing a mathematical model of basin water bodies. Using the raw data, a mathematical model of the basin of Lake Onega. This model can be used for modeling thermal and hydrodynamic processes.
Keywords: parallelization of computations, thermohydrodynamics modeling of water objects, multi-core processors
his paper presents mathematic model of logging timber freights by combine transport network. This model optimize of cargo-carrying and technological roading of forest bases in timber procurement enterprise and lumber factories. Authors developed procedures and functions, which allowed solving optimization of cargo-carrying and technological roading of forest bases in timber procurement enterprise and lumber factories. Authors also analyze technological process on cut-over land, loading bay and railheads. This reporting allows to reduce transport costs and makes optimal schedule of logging timber freights.
Keywords: log truck, rail transportation in timber processing complex
The consideration of basic control homeostatic system is carried out. With a glance on Stepanov’s research result in the area of medical homeostatics the conception of oscillatory homeostatic neural network on the basis of the meridional homeostatic model of human body is generated.
Keywords: homeostat, knowledge, neural network, meridional homeostatic model
This article is devoted to reviewing of crusted composition, based on natural minerals: magnesium chloride (bischofite) and glauconite, as a method of providing an ecological and technical security at traffic areas. In one of the main parametres of road safety - the coefficient of coupling revealed the advantages of using of eco composition over other commonly used anti-icing agents.
Keywords: crusted eco composition, icemelter, coefficient of adhesion, accident rate, ecological security, technical security