State primary standard GET 138-2021 of refractive index, his structure, principle of work, and the metrological characteristics are presented. The modernized standard provides uniformity of measurements of the spectral dependence and spatial distribution of the refractive index of solid and liquid substances in the extended wavelength range from 0.4 to 1.55 microns. The standard GET 138-2021 includes a dynamic goniometer-spectrometer with a ring laser, an autocollimation null indicator and a set of 12 replaceable light sources in the form of laser modules with fi ber output. High-precision and reliable refractometric measurements are necessary in the optical industry to increase the resolution of objectives and other optical devices. Also it is necessary to control the quality and composition of substances in the food, chemical and pharmacological industries.

The results of research and improvement of the National primary standard machine on Brinell hardness scales GET 33-85 are presented. The standard was improved at the Russian Metrological Institute of Technical Physics and Radio Engineering (VNIIFTRI) from 2018 to 2020 in order to ensure the uniformity of hardness measurements according to the Brinell scales. The range of reproduction of Brinell hardness numbers has been expanded, the number of reproducible scales by the standard has been increased. New standard nodes have been developed and created to ensure the reproduction of Brinell hardness numbers in accordance with modern international requirements. The State primary hardness Standard according to the Brinell scales GET 33-2020 has been approved. Metrological characteristics of GET 33-2020 were investigated, a budget of measurement uncertainty was compiled when reproducing hardness numbers according to the Brinell scales. Measuring instruments traceable to GET 33-2020 are used in metallurgy, energy, aerospace, machine tool industry. 

The problem of synonymy of measurements and calculations is considered, which for a long time prevented the proper normative and methodological elaboration of the issues of inadequacy for mathematical models of measurement objects – one of the most important problems of metrology. Conceptually, the solution to the problem of inadequacy in identifying mathematical models based on joint measurements is associated with the transition from synonymy of measurements and calculations to the principle of unity of measurement results and calculation results. A brief description of the topics of the All-Union discussion on the applicability of probabilistic and statistical methods of the 1970–1990s, initiated by A. N. Kolmogorov's question about the objective meaning of probability, is given. Attention is drawn to the fact that during the discussion the mathematical results were criticized, which later formed the basis of the "Guide to the expression of measurement uncertainty" and its applications. The main results of mathematics as a universal language of science related to the solution of measurement problems that expand the understanding of the subject of metrology are analyzed. From this point of view, modern metrology is a fundamental science of methods and means of displaying the properties of measurement objects by mathematical models. The simplest of them are quantities and distributions of values, and the more complex ones are random functions, functionals and operators. The means of selection, in addition to measuring instruments, include computing tools with mathematical, algorithmic and software for solving measurement problems. The connection with the problem of inadequacy of difficulties arising in the training and advanced training of metrologists is noted.

The substance trans-1-chloro-3,3,3-trifluoro-1-propene (R1233zd(E)) refers to fl uorinated hydrocarbon compounds; it is currently being considered as an alternative, fi rstly, to the refrigerant R245fa, which works in organic Rankine cycles. Secondly, R1233zd(E) works as an alternative to the R134a and R123 refrigerants previously used in chillers. To calculate the equilibrium properties (density, entropy, etc.) of this substance, a unifi ed fundamental equation of state (UFEoS) is proposed that satisfi es a number of requirements, including: a) takes into account the asymmetric nature of the behavior of a real fl uid relative to the critical isochore in accordance with the requirements of modern physics of critical phenomena, b) implements the transition of the UFEoS into the virial equation of state in the region of a rarefi ed gas, c) in a wide vicinity of the critical point is consistent with the scaling Berestov equation. On the basis of UFEoS in the temperature range from the triple point temperature, 195.15 K to 450 K and pressures from 0.1 MPa to 100 MPa, thermodynamic tables of standard reference data in the singlephase region and on the saturation line, including density, entropy and enthalpy, speed of sound, isochoric and isobaric heat capacities and heat of vaporization are calculated. Based on GOST 34100.3-2017/ISO/IEC Guide 98-3:2008 and the international methodology recommended for assessing the uncertainty of tabulated data, the uncertainty of the properties included in these standard tables was estimated. A comparative analysis of the properties calculated by the UFEoS with the experimental and literature data on the properties of R1233zd(E) has been made.

One of the problems related to detection of coarse measurements (outliers) in automated processing of data series measured in technical devices has been considered. A modifi cation of the strategy developed by the fi rst author for detecting outliers in time series of noisy data containing an unknown trend is proposed. The previously developed strategy consists of two steps: fi nding a trend and applying to the residues obtained after subtracting the found trend from the measurement data, an algorithm for fi nding the optimal solution. The search for a trend is carried out in the power polynomials class by means of the least squares method using sets with preset number of reference values. The trend search algorithm is carried out using a completely convergent iterative process and is based on the method of minimizing sequences (sets). The disadvantage of this strategy is the need to set a priori the total number of reference values by which the trend is built, which can lead to a distorted determination of the trend and incorrect detection of outliers. In the proposed strategy, the number of reference values is selected from the condition of minimizing the number of detected outliers on the one hand, and from the condition of maximizing the numberof reference values on the other. The results of numerical testing on real data for satellite laser range fi nding measurements are given. The proposed strategy can be used to detect and eliminate outliers from time series of data at the stage of their preliminary processing.

The features of four-circle diffractometers, which are used to identify the composition of substances and materials, as well as to determine many mechanical, physico-chemical and biologically functionally significant characteristics of substances at the arbitration level, are considered. When monitoring the operation and certification of these measuring systems, a system of certified reference materials (СSRM) of diff action properties, including, including the CSRM of the crystal lattice parameter, is used. The characteristics of this and other CSRMs are specified in this work in connection with the need to use the results of measurements on diff ractometers, taking into account the new quantum reality of modern technologies. According to the results of precision measurements of the unit cell size of standard samples of the diffraction properties of silicon CSRM, a change in the structural characteristics with a change in the diameter of the spheres of the samples was found. This size effect, found for the fi rst time in the millimeter range, is similar to the effect observed when changing the size of silicon nanoparticles and other substances with different types of chemical bonding of atoms. It is shown that the size effect must be taken into account when certifying standard samples used in testing four-circle diffractometers. The results are also important for understanding the nanostate of the analyte surface and will be useful in various industries.

In this paper, presents the issues of increasing the reliability of the coordinate systems of laser systems as part of machine tools with numerical control. According to GOST 27803-91 “Adjustable electric drives for metalworking equipment and industrial robots. Technical Requirements” a theoretical assessment of the performance of a controlled electric drive with increased reliability indicators as part of the coordinate system of a laser installation was carried out. A method for calculating the parameters of the laser tool position controller and a generalized mathematical model of the electromechanical circuit of the laser facility are presented. The kinematic scheme is based on a brushless DC motor and a ball screw pair. The presented simulation results comply with the requirements of clause 2.5.7 of GOST 27803-91 and may be useful to developers of information-measuring and control systems for laser installations.

A model of a frame micro-optoelectromechanical angular velocity transducer with electrostatic excitation of primary oscillations is proposed. The transducer includes optical readout units based on the optical tunnel effect, in which precision optical reading of submicrometer movements of the sensing element is implemented. The optical reading unit was experimentally investigatedand the linear region of the function of converting the working gap into optical power was determined. To measure the amplitude of the secondary vibrations of the sensitive element (several hundreds of nanometers), two channels for reading optical signals were used. Values of the parameters of elastic suspensions are found to ensure the secondary movement of the sensitive element in the range of high sensitivity of the optical readout units. The parameters of the proposed transducer and the nonlinearity of the transformation function in the range of measured angular velocities are estimated. The proposed micro-optoelectromechanical transducer can be effectively used for highly sensitive measurement of the angular velocities of moving objects.

The paper investigates the possibility of creating a calibrator of the parameters of signals with digital modulation based on an arbitrary waveform generator. A method is proposed for reproducing calibration signals with a given value of the error vector magnitude by adding a normalized distortion. A particular case of the method is considered, where amplitude and phase modulation is used as the normalized distortion. Experimental confirmation of the possibility of transferring the size of units of the modulation depth and phase deviation from the primary standards GET 166-2020 and GET 180-2010 to the calibrator of the parameters of signals with digital modulation has been obtained.

A method for measuring the wave impedance of a microstrip transmission line with a vector network analyzer is proposed. The problem of determining the frequency dependence of the wave impedance of a microstrip line is relevant for creating circuit models of electronic components and touchstone fi les in a virtual strip channel with a standard wave impedance of 50 Ohm, used in computer-aided design systems for integrated microwave devices. The problem of measuring with a vector network analyzer in the entire frequency range of the device operation is proposed to be solved by the LTR method. This method makes it possible to determine, from the results of measurements by a network analyzer in a coaxial channel, the S-parameters and reflection coefficients of two segments: a short and an electrically long microstrip transmission line: phase velocity and attenuation coefficient of electromagnetic waves propagating in a stripline transmission line; transformed s-parameters of distorting adapters, simulating the contact areas of coaxial and strip lines. In the range from 0.02–2.00 GHz, the impedance is determined by the reflection coefficients from the side of the coaxial ports of the distorting adapters at two fixed frequency points. At these frequency points, the reactive capacitive component of the complex wave impedance is compensated by the inductance of the contact areas of the coaxial and strip lines. The frequency dependence of the real part of the wave impedance passing through the frequency points in the frequency range of the network analyzer is obtained using the circuit model of the Beatty microstrip standard in the NI AWR Design Environment computeraided design system. The model of this standard for a line with an air section between two segments of strip lines with an insulating base was obtained using a circuit analog of MLIN, which is adequate to the physical prototype of the line. The relevance of measuring the wave impedance of a microstrip line with a vector network analyzer is shown by the example of identifying the intrinsic parameters of chip resistors.

The problem of insufficient efficiency and accuracy of diffusion coefficient non-destructive testing methods in thin porous materials is studied. The productivity of diffusion coefficient studies by traditional methods is low due to the need for long-term calibration of diffusant concentration converters in a porous materials. Two methods that make it possible to determine the desired coefficient in the absence of a real static characteristic for the applied diffusant concentration converter are considered. Method I is rigidly tied to fix the time moment, which corresponds to the maximum diffusant concentration after the application of the pulsed action. When determining the desired coefficient by method II, it is possible to select two identical values of the converter output characteristics after a pulse action with fixing the corresponding time points. The comparison of these methods is carried out. The errors of determining the desired coefficient under comparable conditions are investigated by two methods. The possibility of reducing the resulting error for method II by selecting the values included in the calculated expression is analyzed. The results of the study will be useful in the production and operation of products made from porous materials.