相关论文: The irony of the magnet system for Kibble balances…
Although the so-called magnetic geometrical factor, $Bl$, of a Kibble balance does not appear in the Kibble equations, it offers the precision link between electrical and mechanical quantities and furthers a quasi-quantum traceability path…
The Kibble balance has become one of the major instruments for realizing the mass unit, the kilogram, in the revised international system of units (SI). Researchers at about a dozen national metrology institutes are actively working with…
The magnet-moving measurement scheme in Kibble balances avoids displacing force-sensitive components, such as the weighing cell, and enables a broader magnetic profile measurement range during the velocity phase. However, this mechanism…
Employing very simple electro-mechanical principles known from classical physics, the Kibble balance establishes a very precise and absolute link between quantum electrical standards and macroscopic mass or force measurements. The success…
Yoke-based permanent magnetic circuits are widely used in Kibble balance experiments. In these magnetic systems, the coil current, with positive and negative signs in two steps of the weighing measurement, can cause an additional magnetic…
With the adoption of the revised International System of Units (SI), the Kibble balance has become a pivotal instrument for mass calibrations against the Planck constant, $h$. One of the major focuses in the Kibble balance community is…
The design of the permanent magnet system for the new Quantum Electro-Mechanical Metrology Suite (QEMMS) is described. The QEMMS, developed at the National Institute of Standards and Technology (NIST), consists of a Kibble balance, a…
The watt balance is an experiment being pursued in national metrology institutes for precision determination of the Planck constant $h$. In watt balances, the $1/r$ magnetic field, expected to generate a geometrical factor $Bl$ independent…
The Kibble balance realizes the kilogram by linking mechanical and electrical quantities via a magnet system. In an improved BIPM-type magnet design by Tsinghua University, an open/close surface was incorporated, facilitating operation.…
Permanent magnets together with yokes to concentrate the magnetic flux into a cylindrical air-gap are widely employed in Kibble balances. These experiments require a uniform magnetic flux density along a vertical path, typically a…
The magnet system is one of the key elements of a watt balance. For the new watt balance currently under construction at the National Institute of Standards and Technology, a permanent magnet system was chosen. We describe the detailed…
This paper presents recent advances in the KBmini Kibble balance, a tabletop system for E2-accuracy mass calibration up to 1 kg. The $Bl(z)$ profile is characterized by manually setting the magnet at different vertical positions, and the…
The UME Kibble balance project was initiated at the second half of 2014. During this period we have studied the theoretical aspects of Kibble balances in which an oscillating magnet generates AC Faraday voltage in a stationary coil and…
Watt balances are used to measure the Planck constant and will be used in the future to realize mass at the kilogram level. They increasingly rely on permanent magnet systems to generate the magnetic flux. It has been known that the…
A Kibble balance measures the $gravitational$ mass (weight) of a test mass with extreme precision by balancing the gravitational pull on the test mass against the electromagnetic lift force. The uncertainty in such mass measurement is…
We establish the principles for a new generation of simplified and accurate watt balances in which an oscillating magnet generates Faraday's voltage in a stationary coil. A force measuring system and a mechanism providing vertical movements…
The ``Quantum Electro-Mechanical Metrology Suite'' (QEMMS) is being designed and built at the National Institute of Standards and Technology. It includes a Kibble balance, a Graphene quantum Hall resistance array and a Josephson voltage…
Analytically the forces and torques on a coil in a field of magnetic flux density can be calculated one of two ways. The line integral can be conducted along the coil's wire, summing up the differential force contribution. For each…
We studied the anelastic aftereffect of a flexure being used in a Kibble balance, where the flexure is subjected to a large excursion in velocity mode after which a high-precision force comparison is performed. We investigated the effect of…
One of the key issues in magnetic refrigeration is generating the magnetic field that the magnetocaloric material must be subjected to. The magnet constitutes a major part of the expense of a complete magnetic refrigeration system and a…