No. 6

Normalization and comparison of the bands of the maximum error of devices

The applied forms of standardization of the maximum error do not allow normalizing the band of the maximum error of wide-range devices without subranges. This makes it difficult to compare instruments in terms of accuracy and range. The article substantiates the expediency of using for comparison of devices the formula for normalizing the limiting relative measurement error, including the additive, multiplicative and hyperbolic components of the error. An additional degree of freedom, determined by the hyperbolic component, makes it possible to normalize the maximum error without using subranges, and also simplifies the comparison of instruments with a wide measurement range. The article shows that to compare the accuracy of devices, regardless of the differences in their marginal error bands, width and number of measurement subranges, the average reduced limiting measurement error and the number of effective scale quanta are also applicable. Examples of comparison of flow meters using these tools are given.

Keywords: measurement, instruments, accuracy, normalization, maximum error band, additive, multiplicative, hyperbolic, criterion for accuracy and range, wide range, reduced error.

Investigation of a high-resolution laser interference oil manometer measurement uncertainty caused by an optical interferometer with phase modulation

Investigation of a high-resolution laser interference oil manometer measurement uncertainty caused by an optical interferometer with phase modulation (OIPM) has been carried out in order to modernize and improve the metrological characteristics of the laser interference oil manometer (LIOM) which is a part of Russian primary pressure standard GET 101–2011. The article describes the design and principle of the OIPM operation, as well as the method of uncertainty measurement investigation of the interference fringe fractional part. OIPM functionality investigation was carried out by comparing the oscillograms of a real interference signal with a theoretical two-beam interference curve. It was found that the main contribution to the interference fringe fractional part measurement uncertainty is the nonlinearity of the piezoelectric modulator, which is part of the OIPM, deformation dependence on the applied voltage. The research results show that the interference fringe fractional parts measurement uncertainty does not exceed 1/25 of a fringe (0,1 mPa in pressure units), this is approximately 12 times less than LIOM resolution.

Keywords: liquid manometer, laser interferometer, phase modulation, piezoelectric element, fringe fraction measurement, resolution, measurement uncertainty.

Telemetric Data Transmission System with Adaptive Selection of Error-Correcting Code Parameters Based on Neural Methods

The article discusses a telemetry data transmission system with an adaptive selection of parameters of an error-correcting code based on neural network prediction of the state of a communication channel. The study was carried out on a binary symmetric model of a communication channel for the case of using the Bose-Chowdhury-Hockingham error-correcting code. The data obtained prove the possibility of effective application of neural network methods for the considered problem, and also show that the proposed approach allows more efficient use of the communication channel bandwidth in comparison with systems without adaptation.

Keywords: information-measuring system, prediction of the state of the communication channel, nonlinear autoregressive artificial neural network, artificial neural network with long short-term memory, Bose-Chowdhury-Hawkingham code.

Overview of Designs and Calibration Methods for Test Fixtures Contact Devices of Microwave Components

A review and analytical analysis of the designs of strip, coaxial and coaxial/strip test fixtures, as well as methods of their calibration, is given. It is shown that the advantage of coaxial/strip test fixtures is that they can be used to connect simulator/analyzer of microwave devices, both calibration coaxial measures, microstrip loads and microstrip line segments, and active components, such as transistors and its crystals used in microwave amplifiers, oscillators and frequency multipliers. The coaxial nodes of the coaxial/strip test fixture provide their calibration together with the analyzer with coaxial calibration measures. Additional calibration of contact nodes with a minimum set of calibration microstrip loads or microstrip line segments ensures the transfer of measurement planes of the S-parameters of the active component from the coaxial measuring path of the analyzer to the microstrip line. In addition, the method of calibration of the probe test fixture of microcircuit crystals by specialized calibration microstrip loads is considered.

Keywords: strip, coaxial, coaxial-strip and probe test fixture, simulator/analyzer, calibration, transistor, S-parameters.

The most effective method for suppressing thermodonor generation in silicon

It has been established that doping silicon with nickel in the range T = 1000…1250 °C makes it possible to almost completely suppress the generation of thermal donors, both in the process of diffusion and in the process of various low-temperature annealings (T = 300…500 °C), regardless of thermal annealing time. It is shown that clusters of nickel atoms getter oxygen atoms and other uncontrolled impurity atoms. The most effective technological method for producing silicon with stable parameters, in the range of T = 300…1250 °C, has been proposed.

Keywords: diffusion, nickel, gettering, thermal donor generation, silicon.

Comparison of the results of Experimental and Theoretical Studies of Mechanical Stress

In order to scientifically substantiate the experimental methods of ultrasonic testing of mechanical stresses (MS), studies were carried out to measure MS acting in the material of a beam during its bending, and the corresponding calculations were carried out to assess MS. To control the MS at transverse bending of the sample, two sets of MS control devices were used. A set of tools based on a laser-ultrasonic flaw detector and an optoacoustic separately combined transducer that allows an integral assessment of the MS values in the surface layer. And a set of tools based on an ultrasonic flaw detector and a three-component piezoelectric transducer, which allows an integral assessment values of MS along the thickness of the test object. The results of MS measurements using ultrasonic control methods and the calculation results showed satisfactory convergence. It is shown that using simultaneously the two proposed methods for monitoring MS, it is possible to get a complete picture of the stress-strain state of the body. On the other hand, having an idea of the loading scheme of the test object, it is sufficient to measure the MS in the surface layer, since, as has been shown, the average values of the MS over the thickness and over the surface are interrelated.

Keywords: mechanical stresses, ultrasonic method, acoustoelasticity, bending tests.

Using nonlinear phenomena to create underwater reflector markers

The article evaluates the limiting detection range of a new type of underwater markers – passive nonlinear reflectors with an unlimited operating time. This is due to their lack of a power source. The optimal range of operating frequencies has been substantiated taking into account the losses of the hydroacoustic signal in seawater.

Keywords: hydroacoustics, underwater markers, nonlinearity.

High temperature hydrogen annealing for modification of silicon trenches surface

The effect of high temperature hydrogen annealing on the shape transformation of micron-sized trenches formed on a Si(100) substrate was investigated.

It was shown that this process can be realized using cold wall system, because trench corner rounding occurred. It corresponds to experimental data of other researchers. Therefore, the chamber wall temperature does not affect on possibility of structural changes during hydrogen annealing, and the process doesn’t depend on wall temperature of chamber where annealing was going.

Besides that, the obtained samples have the least possible surface defects density of the crystal lattice.

Keywords: high temperature hydrogen annealing, silicon.

Tensoelectric properties of silicon with nanoclusters of manganese atoms

It was found that, in contrast to conventional semiconductor materials, silicon with nanoclusters of manganese atoms exhibits a high tens sensitivity at room temperature, which is difficult to explain by the existing theory. The high tens sensitivity in the obtained material is associated with the changing of state of nanoclusters of manganese atoms in the presence of pressure. These data show that silicon with nanoclusters of manganese atoms can serve as a promising material for creating a new class of strain gauges. By controlling the concentration and charge state of nanoclusters of manganese atoms, one can change the tens sensitivity of the obtained material.

Keywords: semiconductor, pressure, nanocluster, strain gauge, manganese, diffusion.