Sufficient progress towards redefining the International System of Units (SI) in terms of exact
values of fundamental constants has been achieved. Exact values of the Planck constant h …

This paper gives the 1998 self-consistent set of values of the basic constants and conversion
factors of physics and chemistry recommended by the Committee on Data for Science and …

The redefinition of the SI unit of mass in terms of a fixed value of the Planck constant has
been made possible by the Kibble balance, previously known as the watt balance. Once the …

The special least-squares adjustment of the values of the fundamental constants, carried out
by the Committee on Data for Science and Technology (CODATA) in the summer of 2017, is …

On 16 November 2018 a revision of the International System of Units (the SI) was agreed by
the General Conference on Weights and Measures. The definitions of the base units were …

New results are reported from an ongoing international research effort to accurately
determine the Avogadro constant by counting the atoms in an isotopically enriched silicon …

A new single crystal from isotopically enriched silicon was used to determine the Avogadro
constant NA by the x-ray-crystal density method. The new crystal, named Si28-23Pr11, has a …

Abstract Researchers at the National Institute of Standards and Technology (NIST) have
measured the value of the Planck constant to be $\newcommand {\hres}{6.626\, 069\, 934 …

The magnet system is an essential component of the Kibble balance, a device that is used to
realize the unit of mass. It is the source of the magnetic flux, and its importance is captured in …

A precise instrument, called a watt balance, compares mechanical power measured in terms
of the meter, the second, and the kilogram to electrical power measured in terms of the volt …