Reproduction and storage of measurement units are carried out using standards – measuring instruments with the highest accuracy, a key link in the metrological chain of transferring units. The procedure for certification of measurement standards is a key event that confirms the ability of standards to ensure the accuracy and uniformity of measurements. The key factor in the standard certification procedure is the correct definition of the intervals between certifications.

The main direction of development of the legislative base of metrology in the Russian Federation is strengthening the order and discipline in the field of ensuring the uniformity of measurements. Failure to comply with the certification procedure by legal entities entails significant fines. The improvement of methods for determining intervals between certifications of standards is becoming more relevant in modern metrology.

The purpose of the work is a solution of methodological problems of determining intervals between certifications of measurement standards. The publication reveals the contradictions that arise when determining the intervals between certifications of standards, as well as the disadvantages of the current certification procedure and their methodological reasons.

As a solution to the identified problems, directions for improving the existing scientific and methodological apparatus for determining intervals between certifications are identified. In particular, a decision tree is proposed as a tool that allows choosing one of the methods for determining intervals between certifications based on an analysis of the composition of the initial data.

The article describes the principle of operation of a laser interferometric oil manometer from the GET 101-2011 – State Primary Measurement Standard for the pressure unit in the field of absolute pressure in the range 1 · 10^–1 ÷ 7 · 10⁵ Pa and its error budget. The article compares the metrological characteristics of the laser interferometric oil manometer with foreign analogues based on the results of international key comparisons. The problems of measuring low absolute pressure in the range of 0.1–1 000 Pa using the laser interferometric oil manometer and possible solutions to these problems are considered. A study of the influence of degassing and compressibility effects on the density of the working fluid of the laser interferometric oil manometer is described, and an analysis of the research results is presented. The idea of increasing the resolution of pressure measurements using the laser interferometric oil manometer is described. An analysis of the possibilities of measuring pressure using the laser interferometric oil manometer is carried out, provided that it is equipped with an optical interferometric device with phase modulation in order to increase the resolution of the pressure manometer and taking into account the research results of the physico-chemical properties of the working fluid of the pressure manometer.

Raman spectroscopy is mainly used for qualitative analysis, since the intensity of Raman lines is instrument dependent. At the same time, the high selectivity of Raman spectra stimulates interest in finding ways to use them for quantitative analysis as well, and the development of methods to effectively apply Raman spectroscopy for quantitative analysis is quite relevant.

The aim of the study was to investigate the possibilities of using the measure developed at the All-Russian Scientific Research Institute for Optical and Physical Measurements and designed for calibration of Raman instruments on the Raman shift wavenumber scale for quantitative analysis from Raman spectra.

The developed measure (registration number in the Federal Information Fund for Ensuring Uniformity of Measurements 93847-24) is a polymer film made of polystyrene with sulfur addition and allows storing and transmitting a unit of Raman shift wavenumber for Raman scattering excitation wavelengths of 532, 633 and 785 nm.

The possibility of using this measure for quantitative analysis of substances by measuring the intensity of Raman lines in instrument-independent units is considered. It was found that the use of the measure allows to determine the volume fraction of individual substances (ethanol) with relative random error less than 3 % and relative systematic error less than 6 %. To analyze multicomponent mixtures (alcohols, sugars) with the help of the measure, a multivariate calibration was constructed using the Partial Least Squares method. In this case, the volume fraction of components in an unknown sample was determined with a relative error not exceeding 15 %.

The practical significance of the obtained study results allows to calibrate Raman microscopes and spectrometers on the Raman shift wavenumber scale, as well as to carry out quantitative analysis of individual substances and multicomponent systems using Raman spectroscopy.

The article considers the problem of the lack of traceability of mechanical deformation measurement results to state standards of measurement units and describes a study aimed at developing a verification schedule design. The requirements for metrological characteristics of strain gauges presented in domestic and foreign standards are analyzed. The main methods of standardization of metrological characteristics are defined; their comparative analysis is carried out. The advantages and disadvantages of standardization of metrological characteristics of extensometers defined in ISO 9513 and ASTM E83 are established. A unified approach to the method of expressing permissible error values in units adopted for measuring mechanical deformation is proposed, and the procedure for transferring the unit of deformation to such measuring instruments as extensometers, strain gauges and measuring transducers of deformation is presented. The proposed verification schedule for deformation measuring instruments is important in establishing the metrological traceability of deformation measuring instruments used in uniaxial tests.

The work is focused on issues that need to be taken into account when creating a unified system of metrological support for deformation measurements, in particular, the need to introduce a classification of deformation measuring instruments, methods for standardizing metrological characteristics, and methods for transferring units from standards to deformation measuring instruments.

The article is devoted to the development of methods for measuring the characteristics of the steel ductility during static tensile testing – relative elongation and relative contraction after rupture.

The objectives of the work were to analyze the uncertainty budgets of measurements of relative elongation and relative contraction after rupture determined during static tensile testing, optimize the measurement parameters associated with sample preparation using methodological factors, assess the contributions to the measurement uncertainty budgets during the development of measurement methods, and develop methods for measuring relative elongation and relative contraction after rupture intended to assess the accuracy of measurement results obtained using standard methods for measuring the same quantities according to GOST 1497–2023 «Metals. Tensile test methods».

In the course of the work, theoretical and experimental studies were carried out to compile uncertainty budgets for measurements of relative elongation and relative contraction after rupture, indicating the identified sources of uncertainty. Metrological characteristics of measurement methods were calculated.

As a result of the study, two methods for measuring the characteristics of steel ductility using a video measuring microscope were developed and certified, providing a margin of accuracy compared to the standardized measurement method according to GOST 1497–2023, intended for testing for the purpose of approving the type of reference materials.

The article discusses the features and problems of metrological quality assurance of measure- ments of parameters of optical single-crystal materials and elements made of them using examples of measurements of parameters of dielectric ionic optical materials from the practice of the interdepartmental educational and testing laboratory of semiconductor materials and dielectrics «Single crystals and blanks stock on their base» of NUST MISIS.

It has been established that the properties of grown crystals can be adjusted by exposing numerous structural point defects, which control the properties of the crystals, to external influences. Evidence is provided that the approach «structure – structure defects – properties – application of defects to control properties – ad- justment of crystal production technology» is the most effective for studying the physical parameters of dielectric crystals.

The article contains a summary of information from regulatory documents, original articles, reviews and monographs on the problems of metrological assurance in the field of solid state physics. The material is based on the results of the authors’ analysis of the influence of structural point growth defects on the properties and technological parameters of crystals. The review is based on long-term experience with optical dielectric crystals in the laboratory where the authors of the publication work. The key conclusions are based on the au- thors’ dissertations for scientific degrees, information from reports at domestic and international conferences. The review is intended for specialists – metrologists for theoretical and applied research. In addition, the published material may be useful to teachers and students of specialized areas of higher education institutions.