Patrick M C Rourke,Christof Gaiser,Bo Gao et al.
Patrick M C Rourke et al.
The principles and techniques of primary refractive-index gas thermometry (RIGT) are reviewed. Absolute primary RIGT using microwave measurements of helium-filled quasispherical resonators has been implemented at the temperatures of the tri...
The Boltzmann project [0.03%]
玻尔兹曼项目
J Fischer,B Fellmuth,C Gaiser et al.
J Fischer et al.
The International Committee for Weights and Measures (CIPM), at its meeting in October 2017, followed the recommendation of the Consultative Committee for Units (CCU) on the redefinition of the kilogram, ampere, kelvin and mole. For the red...
Mattias Kruskopf,Randolph E Elmquist
Mattias Kruskopf
Graphene-based quantised Hall resistance standards promise high precision for the unit ohm under less exclusive measurement conditions, enabling the use of compact measurement systems. To meet the requirements of metrological applications, ...
Challenges to miniaturizing cold atom technology for deployable vacuum metrology [0.03%]
冷原子技术微型化面临的挑战及真空计量应用
Stephen Eckel,Daniel S Barker,James A Fedchak et al.
Stephen Eckel et al.
Cold atoms are excellent metrological tools; they currently realize SI time and, soon, SI pressure in the ultra-high (UHV) and extreme high vacuum (XHV) regimes. The development of primary, vacuum metrology based on cold atoms currently fal...
A T Yue,E S Anderson,M S Dewey et al.
A T Yue et al.
A technique for establishing the total neutron rate of a highly-collimated monochromatic cold neutron beam was demonstrated using an alpha-gamma counter. The method involves only the counting of measured rates and is independent of neutron ...
Edward Hanson,Douglas Olson,Haijun Liu et al.
Edward Hanson et al.
We describe our progress in developing the infrastructure for traceable transient measurements of pressure. Towards that end, we have built and characterized a dual diaphragm shock tube that allows us to achieve shock amplitude reproducibil...
Traceable Calibration and Demonstration of a Portable Dynamic Force Transfer Standard [0.03%]
便携式动态力值传递标准的溯源标定及现场比对
Nicholas Vlajic,Ako Chijioke
Nicholas Vlajic
In general, the dynamic sensitivity of a force transducer depends upon the mechanical system in which it is used. This dependence serves as motivation to develop a dynamic force transfer standard, which can be used to calibrate an applicati...
Nicholas Vlajic,Ako Chijioke
Nicholas Vlajic
We describe an apparatus for traceable, dynamic calibration of force transducers using harmonic excitation, and report calibration measurements of force transducers using this apparatus. In this system, the force applied to the transducer i...
Determination of the Boltzmann constant with cylindrical acoustic gas thermometry: new and previous results combined [0.03%]
圆筒形声学气体温度计的玻尔兹曼常数测定：新旧结果合并
X J Feng,J T Zhang,H Lin et al.
X J Feng et al.
We report a new determination of the Boltzmann constant kB using a cylindrical acoustic gas thermometer. We determined the length of the copper cavity from measurements of its microwave resonance frequencies. This contrasts with our previou...
Determination of the molar mass of argon from high-precision acoustic comparisons [0.03%]
高精度声学比较法确定氩的摩尔质量
X J Feng,J T Zhang,M R Moldover et al.
X J Feng et al.
This article describes the accurate determination of the molar mass M of a sample of argon gas used for the determination of the Boltzmann constant. The method of one of the authors (Moldover et al 1988 J. Res. Natl. Bur. Stand.93 85-144) u...