Том 60, № 12 (2018)

Following many years of intense investigations, leading to significant progress with the determination of fundamental constants, it is now likely that the General Conference for Weights and Measures (CGPM) will approve revised definitions for the SI base units at its next meeting in November 2018. It is proposed that the definitions for the kilogram, the ampere, the kelvin, and the mole will be based on new physical concepts, whereas the definitions for the second, the meter and the candela will only be reformulated. As a consequence, the units of the revised SI would be derived from a set of seven defining constants. This article describes the principal shortcomings of the present SI, the planned changes and the consequences for the realization and dissemination of units in the different fields of metrology.

An overview of the current status of the development of a nuclear clock based on the state of lowest known nuclear excitation energy in ²²⁹Th is presented. The text is especially written for the interested reader without any particular knowledge in this field of research. It is thus ideal as an introductory reading to get a broad overview of the various different aspects of the field; in addition, it can serve as a guideline for future research. An introductory part is provided, giving a historic context and explaining the fundamental concept of clocks. Finally, potential candidates for nuclear clocks other than ²²⁹Th are discussed.

The functional capabilities of State Primary Standard GET 12–2011 of the units of magnetic induction, magnetic flux, magnetic moment, and gradient of magnetic induction are investigated for the purpose of expanding the range of measurements in the transmission of the unit of magnetic induction into the area of measurements of strong and weak magnetic fields as well as in the transmission of the unit of magnetic flux by instruments for measuring the parameters of magnetically soft materials.

The need to improve the State Primary Special Standard of the unit of mass concentration of particles in aerodispersed media GET 164–2003 is demonstrated. The structure of the standard is considered, methods of reproduction and transmission of the unit are described, and the basic metrological characteristics of the standard are presented. The improved standard GET 164–2016 is presented. A comparative analysis of the characteristics of the two standards is performed.

Specifications for methods of measuring the concentration of hydrogen in solid samples are analyzed. Multiple discrepancies in the results of comparisons of modern standard samples from different manufacturers are found experimentally and the probable source of these discrepancies is the method used to heat and melt samples in a carrier gas flow for the measurements. It is concluded that this method is unsuitable for metrological support of measurements of the concentration of hydrogen in structural materials, since the metrological characteristics of these means of measurement do not meet the requirements for safe operation in the modern economy.

This paper introduces the Prism, a new type of signal processing block, as a contribution to the challenges of 21st Century metrology. The Prism is a fully recursive, dual output, FIR filter: the computational burden is low and independent of data window length. Prism design is trivial, so that networks of Prisms can be created, whether at design time or autonomously in real time, to carry out a range of metrological tasks. Prism-based trackers can generate sample-by-sample estimates of frequency, phase, and/or amplitude of a sinusoid. A simulation example of sensor validation demonstrates how Prism signal processing can be used to autonomously detect, track, and compensate for an undesired frequency component in a frequency-based sensor.

Results from an experimental study of the reflectivity of radiation adsorbent materials probed by ultrashort electromagnetic radiation are presented. Ultra wide-band pulsed microwave spectroscopic methods are used. Measurements of reflectivity by traditional narrow band and ultra-wide band techniques are compared.

Modernization of instruments for the measurement of linear and angular displacements with the use of small-period optical measures, multiplicative transducers of scanning compensation guidance interpolators, and a universal signal processing system is considered.

A method is proposed for determining the parameters of the smoothing window function in pulsed spectroscopy. It is based on coupling the window to the spectral and energy centers of a pulsed signal recorded in a spectrogram.