The problem of increasing the accuracy of determining the magnetic moment of the cesium-133 nucleus, which is used as a reference standard for determining the magnetic properties of short-lived cesium isotopes, is considered. Experimental results of determining the ratio of the resonance frequencies of water protons and ₁₃₃Cs nuclei for aqueous solutions of CsF, CsCl and CsNO₃ with concentrations from 0.1 to 0.4 Mol/kg H₂O are presented. As a result, of the simultaneous registration of nuclear magnetic resonance signals of water protons and cesium-133 nuclei, random and systematic uncertainty in determining the ratio of the resonance frequencies of water and cesium protons to units of the eighth decimal place are minimized. Extrapolation of the content of cesium salts in water to zero concentrations was carried out. For single cesium ions in water, the resonance frequency ratio 7.6241815(2) was determined. The magnetic moment of the cesium-133 nucleus was calculated taking into account the data for the magnetic moment of the proton, the screening of protons in water, and the known data on the screening of cesium ions in water. As a result, the magnetic moment of the cesium-133 nucleus was determined: 2.58243(12), which was compared with the data of other authors. The study of solutions of cesium salts in water revealed an anomalously large dependence of the resonance frequency of cesium nuclei on the solution temperature, which is 12 times higher than the analogous dependence of the resonance frequency of water protons.

The problems of calibration of measuring instruments are discussed. A brief overview of the 1978–1992 discussion on the applicability of statistical methods and its lessons is given. According to the normative documents, the transformation of ideas about calibration is traced. The general measurement problem of tests for the purpose of type approval, verification and calibration of measuring instruments is considered as the problem of identification of functional metrological characteristics. When checking measuring instruments under normal conditions, the importance of their calibration for operating conditions is noted. The main difficulty of solving this problem is the multidimensional nature of the calibration function model and the need to take into account the errors of its inadequacy along with the measurement errors. It is shown that taking into account only one of these components can lead to excessive complication of the model with the loss of its stability, or to the use of insufficiently complete models that create the appearance of high accuracy. An example of calibration of a measuring instrument for operating conditions by two influencing values is given.

The method of automated measurement of coordinates of digital images of centrally symmetric artificial objects proposed by the authors is considered in order to analyze the possibility of its application in software complexes for processing images obtained by a remote sensing system. Two correlation algorithms are proposed for the implementation of the method that allows determining the coordinates of the centers of digital images of artificial objects with subpixel accuracy. The influence of the discrete structure of raster images on the measurement accuracy is investigated. Calculations of errors in measuring the coordinates of digital images are given. An experiment with the use of the author's software on automated determination of the coordinates of the centers of images of radial test-objects for measuring optical resolution obtained from real surveys is described, confirming the effectiveness of the proposed method.

The problem of investigating the temporal structure of optical pulses in nano- and picosecond ranges and measuring their temporal characteristics is considered. In order to solve the problem, measuring instruments of temporal characteristics of optical pulses have been created – the miniature image converter streak cameras having picosecond temporal resolution. The functional capabilities and application examples of the cameras are described. Operating principle, design, features and functions of the created cameras are considered. The technological process of manufacturing of the image converter streak tubes for the image converter streak cameras implemented on the unique high-vacuum technological complex is described. Features of the software used to control the image acquisition process as well as for processing and analysis of the images captured by the image converter streak cameras, are considered. Metrological and main technical specifications of the miniature image converter streak cameras are given. Using the miniature image converter streak camera, the temporal structure of emission of a semiconductor pulsed laser was investigated, the pulse shape was determined and the pulse duration was measured with error estimation. It is demonstrated that the miniature picosecond image converter streak cameras are effective instruments for emission parameters control of nano- and picosecond pulsed lasers during their development, setup, tests and operation. The information about real temporal shape of laser pulses obtained by means of image converter streak cameras is relevant for designers of pulsed lasers as well as for specialists in laser ranging and spectroscopy.

The article discusses a design of an optical flow meter for monitoring the flow rate of a coolant in a pipeline, both in laminar and turbulent flow regimes at different temperatures. A method for measuring the flow rate of the coolant based on the registration of γ-radiation from changes in its oxygen activity has been developed. The design of sensors for recording oxygen activity based on optical fiber and a method for their placement on the pipeline are proposed. The optimal value of doping the core of an optical fiber with germanium oxide for measuring the flow rate of the coolant q at various intensities of oxygen activity in it has been established. A method is proposed for restoring the transparency of an optical fiber when measuring q in the presence of γ-radiation. The technique for measuring q is considered in detail and the features of its implementation are noted. The results of investigating the operation of an optical flow meter on an experimental stand are presented

The paper describes the design of the control system of the reference adiabatic calorimeter, which is part of the state standard for the unit of specific heat of solids GET 60-2019. The hardware implementation and control algorithms that ensure the required measurement accuracy are considered in detail. The digital control system provides an adiabatic mode of operation of the calorimeter in the range of 30-600 °C by maintaining the set temperature difference with an error of less than 0.06 °C in the dynamic mode and less than 0.001 °C in the static one. A predictive PID controller is used for control, the parameters of which are determined on the basis of a mathematical model.

The article describes the problem of reducing the measurement uncertainties of the electrodynamic characteristics of antenna radiation using the far-field measuring systems. The most significant limitations in such measurements are the sphericity of the phase front and multipath reflections. The impossibility of ensuring the specified conditions can lead to unacceptable measurement uncertainties and to the need of using another measurement system’s type. A method is proposed for increasing the accuracy of measuring antenna radiation patterns in the Fresnel zone under conditions of multipath reflections. The considered method can expand the nomenclature of antennas tested by the far-field measuring systems. The use of this method can significantly reduce the requirements for the characteristics of measuring systems and, therefore, reduce the cost of antenna testing. The essence of the proposed method is to synthesize the spatial (two- or three-dimensional) impulse response of the antenna by transforming the original frequency-angular dependence of the transmission coefficient. The physical meaning of the transformation can be interpreted as the reconstruction of the equivalent field distributions containing the test antenna or its geometric projection onto the rotation plane. The reducing of uncertainty caused by the multipath propagation of the electromagnetic field achieves by the filtering of the synthesized antenna spatial impulse response from the signals outside of the allocated volume. The used transformations linearity allows the possibility of recalculating the synthesized characteristic to an arbitrary distance. Thus, it is possible to reconstruct the antenna pattern in the Fraunhofer region and reduce the uncertainty caused by the electromagnetic field wavefront sphericity. The feature of the proposed method is the significant signal-to-noise ratio increase. The main theoretical relations and the results of experimental studies on testing the method are presented in this article.

A method has been proposed and a procedure has been developed for determining the standard deviation and nonexcluded systematic error in reproducing of the complex reflection coefficient unit in waveguides. The reproduction error was found to be dependent on the value of the measured complex reflection coefficient for a specific frequency, and its dominant component is due to the error in measuring the depth of short-circuit measures. The obtained results of determining the reproduction error are advisable to use in the form of tables to assess the error in the measurement results of the complex reflection coefficient. The proposed procedure was shown to be used for determination of the indicators of the accuracy of measurements of the complex reflection coefficient in the creation of the State Primary Standard for the complex reflection coefficient unit in standardized waveguides at frequencies up to 178.4 GHz.

The problem of “aging” of personal biometric data over time is considered. A method is proposed to overcome it by automatically updating the personal biometric data by using the speech signals of registered users obtained during latest requests for their identification and online service. The proposed method uses a scale-invariant indicator of the voice template quality. As a consequence, it is characterized by guaranteed reliability of the decisions made in the conditions of a wide speech signal dynamic range. It is shown that a guaranteed level of significance of decisions made by an observer is provided. The proposed method is implemented in a special software, which was used to experimentally estimate its effectiveness with real speech data. The obtained results are intended for use in the development of new and modernization of existing software and technologies for the personal biometric data automated quality control and updating.

The creation of adsorbents based on natural phylosilicates is one of the primary tasks of modern materials science. In its solution, the control of the granulometric composition of the powders is a prerequisite. The issues of controlling the particle size distribution and electrokinetic potential of phyllosilicates by the method of photon correlation spectroscopy are considered. Stable standardly prepared colloidal solutions of powders of kaolinite and montmorillonite clays from deposits of the Orenburg region are analyzed. The highest quality solution with objects accessible for observation was obtained near the isoelectric cleavage point of minerals (potential of hydrogen  pH=6,5). The modal effective diameters of non-agglomerated particles of kaolinite and montmorillonite have been determined. The formation of ultra- and microaggregates of micron-sized particles was established, interacting both along the basal planes and by the type of basal-lateral cleavage. The dependence of the electrokinetic potential of a suspension of kaolinite and montmorillonite particles on the pH of the medium has been measured. It is shown that the behavior of particles of both types in an electric field in a suspension with pH>5 is practically the same, and the main differences are manifested in an acidic medium: the isoelectric point for kaolinite is close to and for montmorillonite pH=3,5.