Katsumi Fujii

TL;DR: A new approach for the molar Planck constant determination by counting the atoms in 1 kg single-crystal spheres, which are highly enriched with the 28Si isotope, is described, which is the most accurate input datum for a new definition of the kilogram.

TL;DR: In this paper, the authors compared the relative permittivity and dielectric loss between vector network analyzer (VNA) and time-domain spectroscopy (TDS) in the frequency domain.

Abstract: In the International Avogadro Coordination (IAC) Project using the X-ray crystal density method, volume measurements of silicon spheres by optical interferometry play a crucial role for the density measurement of the 28Si-enriched crystal. To confirm the reliability of the volume measurement, specified diameters of a silicon sphere were measured independently by optical interferometers at NMIJ (Japan), PTB (Germany) and NMIA (Australia). The sphere was washed before the measurement with the same procedure. The directions of the diameters were identified with reference marks prepared on the surface of the sphere. All of the results agree with each other within their uncertainties. This strongly confirms the reliability of the diameter and volume measurements in the IAC project.

TL;DR: This study of high gain antennas of horn, cassegrain and off-set parabolic types are developed, and these antenna radiation patterns are measured at 300 GHz and it is found that they have good agreements.

TL;DR: In this paper, a calculable loop antenna consisting of a loop element and a 180 degrees hybrid junction is proposed for measuring loop antennas used in the frequency band below 30 MHz, where a standard loop antenna generates a well-defined magnetic field at an antenna under calibration.