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  • The investigation of properties of gas sensitive materials based on SiO2SnOxCuOy thin films used in gas sensors for multisensory air monitoring system

    The establishment of automated air monitoring systems is a promising way of the air monitoring devices development. The comparative analysis of literature has shown that thin films based on semiconductor metal oxides are effective and widely used material for air monitoring systems creation. In order to create effective and more sensitive sensors it is important to research processes that occur on the surface of the gas sensitive material when it contacts with different substances. The processes that proceed on the surface of gas sensitive material based on SiO2SnOxCuOy during the interaction with molecules of nitrogen dioxide. Quantum chemical calculations have shown that there are three possible mechanisms of interaction between the molecules of nitrogen dioxide with a surface of gas sensitive material.

    Keywords: multitouch system of the monitoring, gas-sensitive material, molecules of dioxide of nitrogen

  • The influence of multiple-charge impurity centers on the potential distribution in the semiconductor surficial region

    The mathematical model of the potential distribution in the semiconductor surficial region in the presence of deep-lying levels in its forbidden zone which specified by multiple-charge impurity centers has been developed. The simulation results can be used for the width of the space charge region estimation, for the prognostication of the most probable mechanism of the charge carriers transfer in metal-semiconductor structure with multiple-charge deep-lying levels and also for the prognostication of the barrier capacitance value. It can be used in the development of solid-state electronic devices with improved values of some parameters.

    Keywords: Poisson’s equation, multiple-charge impurity center, potential distribution, deep-lying levels

  • Sensitivity analysis of ZnO thin film deposited by rf reactive magnetron sputtering

      Results of researches of gas sensitive properties of zinc oxide films grown by reactive rf magnetron sputtering was shown. Process parameters, affected on the gas-sensitive ratio, response time, recovery time and the type of electrical conductivity of obtained films were identified. Optimal modes of magnetron sputtering of zinc oxide for implementing gas sensors (RF sputtering Zn target in a gas mixture of oxygen and argon at a concentration of 80% oxygen, a chamber pressure of 0.8 Pa and the magnetron power 100 W) were established. Avarage response time on NO2 gas was 5-15 sec.  The obtained values ​​of the gas-sensitivity were in the range 30-67% for NO2 concentrations from 20 to 100 ppm, CO and CO2 from 50 to 100 ppm and 81-97% for higher gas concentrations from 500 to 1000 ppm.  

    Keywords: Nanotechnology, magnetron sputtering, zinc oxide, thin films, gas sensitivity

  • Development of sensors based on ferroelectric films for hybrid sensor systems

      In this work researches of structural and electrophysical properties of ferroelectric films of lead zirconate titanate (PZT) which afterwards is planned to apply in hybrid sensor systems are done. Values of capacities of the received samples are in the range from 200 to 1100 pF, the range of thickness of the received films is 300-1000 nanometers. X-ray analysis showed direct dependence of the quantitative maintenance of crystalline PZT in film structure from partial pressure of oxygen in the camera. By results of research the range of polarization of samples are in the range 0,06 – 2,2 µC/cm2, and values of calculated piezoelectric modules are in the range 0,04*10-12 – 13,3*10-12 C/N.

    Keywords: sensors, segnetoelektric films, touch systems, piezoelectric modules.

  • Accounting for the effects of differences between the moduli of elasticity in compression and tension in the calculation of the strength of reinforced beams with filler of foamy fibrous concrete

    The article investigates the impact on the normal stresses of inequality of the young modulus for tension and compression in the bending of reinforced beams. Obtained formulas for determination of the bending moments that arise in the fixture, compressed and stretched zone of the aggregate. Found the formula for the normal stresses arbitrarily supported reinforced beams, arbitrary cross section and arbitrarily loaded bending loads. For example, reinforced beams of rectangular cross-section shows the determination of the neutral line and maximum stresses.

    Keywords: reinforced beam, elastic modulus, stress, normal concrete

  • Cracking of reinforced-concrete elements with holes during torsion and during torsion wist

    Cracking of reinforced-concrete elements with holes is examined. Comparison of theoretical and experiment moments of crack’s  formation during torsion, and during intensive torsion with twist. Formula for practical calculations of cracking of reinforced-concrete elements with holes during torsion and formula for estimate of cracking of reinforced-concrete elements with holes during intensive torsion with twist is suggested.

    Keywords: Crack, twist, torsion, reinforced-concrete, elements, hole, beam

  • A method of numerical modeling of spectrometric systems of gas sensors

      A principle of spectrometric systems of gas sensors was described. A model and a method of numerical modeling of spectrometric gas sensor with the combined radiator-receiver of infrared radiation on the basis of the punched semiconductor thermoresistor were proposed.

    Keywords: spectrometric gas sensor, model, method of modeling

  • Micropower selective amplifier in basis in radiation-hard process technology ABMK_1_3

    Classical implementation of active selective amplifiers (SA) are usually associated with design sophisticated active elements (operational amplifiers) that consume relatively large power from their universality. This paper present the active SA based on an analog array chip ABMK_1_3, that have high level of radiation resistance to the flow of neutrons and accumulated dose of radiation. This SA implemented on the basis of a voltage-to-current converter with a minimum number of transistors and low consumption static current. Efficient use of current amplifier can be explained by use frequency dependent symmetric chains in a feedback loop. This property provides the independence of the pole frequency f0 = fp on the gain of the active element, as well as maximizing the quality factor.
    The basic analytical expressions that establish the relationships between the SA and the characteristics of active and passive components are given. The relations that help minimize sensitivity of parameters SA to instability properties of the components are considered. Simulation results of desired SA are shown.  

    Keywords: selective amplifier, bandpass filter, active RC-filter, analog array chip, radiation hardness

  • Principles for the development of biopotential amplifiers and method of processing data on reactions

      The requirements to be met by a data acquisition system in terms of each of the problems to be solved. Presented electric concept developed biopotential amplifier with a total gain of 2000. The theoretical model of the spectrum of RR intervals and changes depending on the running processes. The analysis revealed that the resulting spectrum satisfies the conditions considered in the theoretical model, and can be further analyzed with fractal characteristics.

    Keywords: Instrumental amplifier, biopotential, fractal index

  • Multichannel OpAmp and JFET follower IC on radiation hardened array

    The features of circuit engineering and results of chip computer simulation which consists of 4-channel operational amplifier (op amp) and 2-channel electrometric voltage follower, designed for pre-processing of sensors signals in high-energy physics are considered. 
    The characteristic properties of designed op amp are the absence of current source in the input differential stage and the use of parallel high-frequency channel for increasing of the bandwidth and slew rate.
    The results of experimental research that have confirmed the low sensitivity of the parameters of designed integrated circuits created on the field programmable gate array "FGPA-1.3" without the horizontal p-n-p transistors to the influence of gamma-irradiation and electrons with energy of 4 MeV are given.  

    Keywords: operational amplifier, field programmable gate array, voltage follower, sensor, sensing element, radiation resistance.

  • The concept of organization of processing of the information in the systems of diagnostics and detection

     In the article there are considered the problems arising in the building of systems of diagnostics and recognition, provides methods to detect deviations in functioning of the various objects.

    Keywords: Diagnostics, еmpirical mode decomposition, extreme filtering, time-frequency distributions

  • Analysis of the conditions of biogas at the landfill for the disposal of solid waste consumption

    Submitted manufacturing operations performed at the landfill site TOP, their main types of negative impacts on the environment. The conditions of formation and emission of biogas generated in the interior of the landfill body and having a pronounced toxic effects. The dependence of the specific biogas yield for the period of his active stable generation.

    Keywords: Solid waste consumption, landfill disposal TOP, biogas, wet waste, environmental safety

  • The method of extension operating frequency range of source and emitter voltage follower

    The paper discusses the features of method of extension of circuit’s operating frequency range of the source and the classical emitter voltage follower (VF). The features of this method based on the effect of the mutual compensation of the parasitic impedances are considered. Problem of improving operation speed of VF with output capacitance and reducing the time of establishment of transient at pulsed input voltage are discussed.
    The simulation results of VF in Cadence on model of SiGe integrated transistors are given. This shows that with capacitive load high-frequency cutoff, the time of establishment of transient and the slew rate improved to tens - hundreds of times. 
    The results of investigate complement of methods of improving operation speed of the classical stage with a common drain and common collector.

    Keywords: operating frequency range, source follower, emitter follower, operational speed, broadband amplifier

  • Method of compensation offset voltage operational amplifiers with classical input stages based current mirrors

    Are considered method of reducing one of the most essential components of the voltage offset Uvo operational amplifiers (op-amp), executed on classical architecture with current mirrors, which is linked to the change current gain of base (β) bipolar transistors in conditions of temperature and radiation effects.
    To solve this problem in the basic architecture of op-amp is entered special corrective multipole, which will provide low-current asymmetry in coordination of input differential stage (DS). The method is applicable to op-amp, which is inexpedient to make any adjustments to the original structure of the DS. 
    The analytical expressions determining basic parameters the compensation circuits Uvo, and also shows the tabular data that simplify the choice of standard functional components of precision op-amps.  

    Keywords: microelectronics, circuit design, a differential amplifier, operational amplifier, voltage offset, temperature drift, the effect of radiation on the zero level

  • Improving the planning system of in a mixed freight by rail and by sea

    The article is devoted to the planning problem  in the international freight rail and by sea. Identified and dealt with problems in the planning of cargo via Russian ports.

    Keywords: planning, loading, international, rail-waterway