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Devices and Methods of Measurements

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Vol 9, No 4 (2018)
View or download the full issue PDF (Russian)
https://doi.org/10.21122/2220-9506-2017-0-4(56)

Measuring instruments

280-287 1122
Abstract

The object of the research is the development of the method of aperture synthesis of a mirror system designed for remote sensing of the Earth.

The analysis of existing methods for the formation of the synthesized aperture was carried out, their accuracy, cost, and mass-dimensional characteristics were evaluated. A new version of the optical system of the synthetic aperture mirror lens is presented and its optimization is performed in the Zemax software package. An estimate of the accuracy of the designed system has been made; a design variant has been developed that includes a transformation mechanism when the telescope is put into near-earth orbit.

As a result of the study, the design parameters of the base lens were determined: a focal length of 13 m, a main mirror diameter of 800 mm, a field angle of 0.25° for modifying a telescope for a low orbit; and the entire telescope as a whole: the lag from the main axis of the telescope is 1.2 m, the angle of rotation of the flat mirror for combining images (45 + 1,5)°, the signal-to-noise ratio (189 in a low orbit with an angle of the Sun 0°, 15 in the geostationary orbit with a sun angle of 60°).

It has been established that the use of aperture synthesis technology allows the development of highresolution optical-electronic systems with lower production and operation costs compared with classical methods for forming the surface of the main mirror. In the course of the simulation, the instability of the values of the frequency-contrast characteristic with increasing angle of view was determined, which is important for a low near-earth orbit, and the requirement for positioning elements of the optical system was established.

288-295 1337
Abstract

The problems of elaboration and application of microand nanometer sized antennas for the generation and reception of electromagnetic radiation is still relevant in both fundamental and applied aspects. With decreasing antenna size, the frequency of electromagnetic radiation increases, and its power decreases. To increase the radiation power, the periodic (in space) electrodynamic structures are used. The aim of the work is to find the possibility of application of injection and (quasi)ballistic drift of single electrons inside curved carbon nanotubes for emission of electromagnetic waves in the microwave range and to determine the parameters of the radiating system that affect the radiation power.

By the calculation within the framework of classical electrodynamics it is shown the possibility in principle of generation of electromagnetic radiation of the gigahertz range by a stream of single electrons inside a hollow curved dielectric carbon nanotube.

It was found that the spectrum and power of this radiation can be controlled by varying the electron flux density, length and curvature of the hollow nanotube.

The results of the work can be applied for elaboration of a microminiature emitter of microwave electromagnetic radiation based on a curved carbon nanotube in the engineering of contactless probe microscopy.

296-305 797
Abstract

Registration of non-stationary processes, namely snapshot hyperspectral imaging that allows to capture data cube I(x,y,λ) in one measurement act, is of interest for imaging spectroscopy.

The purpose of the work is increasing of spectral resolution of imaging spectrometers with spatial filtering of object image using multislit mask, where a diffractive grating is used as disperser (providing almost constant dispersion in working spectral range), and the data cube is projected on a detector as a set of local spectra from object fragments.

An image is formed on detector by a two-objective telecentric system composed from two lenses focused on infinity so that their front focuses are matched. A diaphragm in the match point allows passing only for beams of needed diffraction order, so along with a bandpass filter near the system entrance they solve a typical problem of diffractive systems – elimination of beams of all orders but a needed one. The approach is implemented in two proposed designs of spectrometers: in the first a telecentric system is based on two multi-lens imaging objectives, in the second – is based on two reflective off-axis parabolic objectives.

In this paper we proposed variants for optical design optimization: normalization of beam incidence on a mask and field curvature compensation; they allow to increase system resolution and to extend application area of multislit dispersive spectrometers; also a design being a synthesis of these two approaches is analyzed. According to simulation results, width on half-maximum in dispersion direction Δl ≤ 10 µm, only for limited field points set Δl ≤ 15 µm, that stands for spectral resolutio

Methods of measurements, monitoring, diagnostics

308-313 760
Abstract

The key element determining stability of the semiconductor devices is a gate dielectric. As its thickness reduces in the process of scaling the combined volume of factors determining its electrophysical properties increases. The purpose of this paper is development of the control express method of the error-free running time of the gate dielectric and study the influence of the rapid thermal treatment of the initial silicon wafers and gate dielectric on its reliability.

The paper proposes a model for evaluation of the reliability indicators of the gate dielectrics as per the trial results of the test MDS-structures by means of applying of the ramp-increasing voltage on the gate up to the moment of the structure breakdown at various velocities of the voltage sweep with measurement of the IV-parameters. The proposed model makes it possible to realize the express method of the reliability evaluation of the thin dielectrics right in the production process of the integrated circuits.

On the basis of this method study of the influence of the rapid thermal treatment of the initial silicon wafers of the KEF 4.5, KDB 12 wafers and formed on them by means of the pyrogenic oxidation of the gate dielectric for the error-free running time were performed. It is shown, that rapid thermal treatment of the initial silicon wafers with their subsequent oxidation results in increase of the error-free running time of the gate dielectric on average from 12.9 to 15.9 years (1.23 times greater). Thermal treatment of the initial silicon wafers and gate dielectric makes it possible to expand the error-free running time up to 25.2 years, i.e.1.89 times more, than in the standard process of the pyrogenic oxidation and 1.5 times more, than under application of the rapid thermal treatment of the initial silicon wafers only.

314-324 1936
Abstract

The well-known method of spatial conductometry is widely used for hydrodynamical investigations in the frame of validation benchmarks. The aim of the work was to develop the method of representativeness substantiation for use of the conductometric sensors in single-phase applications.

The paper presents aspects of wire-mesh sensors (WMS) applications in non-uniform conductivity fields. The equivalent electrical circuits for the measurement cell and WMS are proposed and investigated. The methods of translation from measured conductance to conductivity of the water are discussed. Decomposition of the uncertainty sources and their propagation through measurements are investigated.

To obtain the «cross-talk» effect of the measurements the fi model of WMS fl domain was created. The results of calculations showed the dependence of the measurement results on the conductivity contrast in the cells as well as on the size of the contrast domain. The proposed method of the measurement uncertainty estimate was applied to the real WMS and it’s measurement system. The obtained results are topical for validation tests with the use of tracer methods and WMS.

325-326 812
Abstract

Application of surface and subsurface waves for control of objects with a double-layer structure allows to extend possibilities of diagnostics of their physico-mechanical properties. The purpose of work was to determine conditions and offer recommendations providing measuring of ultrasonic velocity and amplitude of the former modes in protective layers and in basis of object at one-sided access to its surface.

The analysis of an acoustic path of a measuring system in relation to ultrasonic evaluation of the objects having the restricted sizes and the protective coating according to velocity data of the surface and subsurface waves propagation is made. On the basis of representations of beam acoustics the dependences connecting a wavelength of the excited surface and subsurface modes, thickness and width of a controlled object, acoustic base of a sounding are defined. There are to provide a condition leveling of the influence of an acoustical noise created by the reflected and accompanying waves on parameters of acoustic signal with the given quantity of oscillations in an impulse.

The principle opportunity is shown and conditions for determination of velocity of subsurface body waves in the base material which is under a protective coating layer are established. For these purposes on the basis of use of the block of ultrasonic probes the optimum scheme of a sounding is offered and the analytical expression for calculation of required velocity considering varying of thickness of a covering is received.

The method of acoustical measuring realized by a direct and reverse sounding of the objects with small aperture and angle probes was analysed and formulas for determination of speed of subsurface wave under protective layer of the wedge form have been got. An ultrasonic device is suggested for the excitationreception of subsurface waves with different speed in objects (on 20–35 %) using for the acoustic concordance of environments of metallic sound duct as a wedge. Possibility of leveling of interference in a protective layer to control efects in basis of material by a volume wave by creation of supporting echo-signal of longitudinal wave of the set frequency and entered normally to the surface of object was studied.

337-346 1815
Abstract

Analysis of methods for recording and reproducing a three-dimensional image allows to distinguish two different approaches. The fi approach consists in formation of stereoscopic images, the second one provides the formation of an optical object model and includes particularly a group of integral photography methods .
The use of integral photography methods for recording and reproducing volumetric images is relevant due to the lack of fl inherent for stereoscopic methods and relative simplicity of technical implementation. Lens raster used in this method is a possible source of image distortion. This paper aim is to determine the range of parameters of the lens system, namely, the allowable values of the pitch of the lens raster, providing distortions absence caused this raster.
Types of possible distortions and sources of their occurrence are indicated. The requirements for the pitch of the lenticular raster are formulated, based on conditions of false information absence, absence of discontinuity of the image in depth and in the transverse direction, and invisibility of lens elements of the reproduction matrix.
Studies shoed that the lenticular pitch is limited by the four inequalities, three of which limit the pitch value from below, and the fourth one from above. A set of conditions limiting the step of the lens matrix was analyzed. The boundaries of allowable step values depend on four groups of parameters: raster dimensions, location of the subjects, reproduction and observation parameters. Result of the method usage as a dependence of the allowable range of the pitch of the lenticular raster on transverse coordinate of the recorded point with fi values of other parameters is presented.

347-358 1818
Abstract

This article is dedicated to the issue of efficiency increase of fire detection equipment in living accommodation and adjacent spaces. This research is intended to develop the testing methodology for spatial pattern of combustion products, including toxic gases with asphyxiant and irritant effects, in both height and area of rooms in a standard apartment building, as well as correlation identification between controlled by fire alarm parameters of environment in living rooms and dangerous fire factors.

Proposed methodology includes the concentration measurement of the basic gaseous combustion products (asphyxiant and irritant), generated in the process of materials burning in living accommodation. Justification of measurement facilities location in the fire scene and adjacent spaces is provided, considering the most likely position of a person during the evacuation and leisure time. The impact of fire stage on the flow rate of optical radiation diffused by smoke is shown.

The findings will enable to develop the testing methodology for fire detectors designed to protect living accommodations and people located in them, formulate the functioning effectiveness criteria (operation algorithms) for detectors, used in living accommodations.



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ISSN 2220-9506 (Print)
ISSN 2414-0473 (Online)