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  • Modeling of MOSFET parameters in a wide temperature range

    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 parametric method of determining a phase difference of quasi-harmonic signals

    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

  • Raman spectroscopy as a method for structure analysis of individual carbon nanotubes

    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

  • The implementation of parallel algorithmic structures that simulate the ecosystem of lake facilities to multi-core processors

    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

  • Management of reproductive potential in the balanced development of the economy of the region

    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

  • Synthesis of energy-efficient electric train traffic control algorithms in the conditions of overcoming the heterogeneities profile of the track

    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

  • Study of the formation of trihalomethanes in Baghdad water supply system

    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 construction of a mathematical model of the basin of Lake Onega

    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

  • A method of providing of ecology and technical security at traffic areas

    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

  • Patent search in the field of shut-offvalve constructionsfor nuclear power plants, thermal power plants and main piping

    The results of a patent search in the field of shut-off valve constructions for nuclear power plants, thermal power plants and main piping are given.

    Keywords: Nuclear power plants, shut-off valve, construction, main piping

  • The analysis of ways to increase the competitiveness of energy biomass

    Following ways to increase the competitiveness of energy biomass are defined. The research of biomass as a raw material for logging and utilization, state encouragement of its industrial utilization, analysis and biomass supplier and customer market grouping, making of effective equipment for its logging, transportation and utilization, feasibility study of equipment parameters and modes of operations, energy biomass performance improvement.

    Keywords: alternative fuel,energy biomass, biofuel, logging, competition

  • Comparison resolution ability Prony and Bartlett methods when working on background noise of the sea

    Results of comparing the beamwidth and the concentration factor of receiving antenna wich were calculated using the metods of Bartlett and Prony when working on the background noise of the sea are considered. It was shown that efficiency parameter estimation signal sources using Prony methods is higher than when using the method of Bartlett.

    Keywords: Prony algorithm, vector-scalar array,dynamc sea noise, the covariance, the flow of power

  • Model the behavior of Autonomous script in the tasks of management of distributed information resources

    The article has received the further development of application technologies autonomous scripts for management of information resources of computer systems. Formalized behaviour of deterministic and stochastic autonomous scripts with the use of finite automata that enables you to develop models and technology for solving a wide class of problems of information resources management.

    Keywords: autonomous scripts, theory of finite automata, the concept of frames slot, management of distributed information resources

  • Features of development of light self-compacting concrete on porous fillers

    Possibility of receiving lungs self compacting concrete is considered. The technique of a choice of components of a raw mix is offered and are brought physics - mechanical characteristics of a ready construction materia  

    Keywords: Self-compacting concrete, the supersoftener, knitting, filler.

  • Mathematical modeling of heat transfer processes in energy-saving solar plants

    A mathematical model of heat transfer processes, the discrete model is based on the finite difference method, and the results of calculations of the temperature distribution also will be developed. In addition the program was created which allows to calculate the distribution of temperature over its entire length for given values ​​of insolation, ambient air temperature and air velocity inside the collector  

    Keywords: mathematical modeling, finite difference method, heat transfer processes, solar collector