Our R&D efforts in this field cover standards for mass, force, torque, pressure, vacuum, acceleration due to gravitational acceleration, gas and liquid flow, and gas flow velocity. Commerce, social activities, the safety of technology, and aerospace and transport equipment all depend on a precise evaluation of the total quantities of materials. This is our sphere of activity. The world's highest class national standard for petroleum flow was recently completed at the Tsukuba North Center and is helping to accelerate technological development for the supply of the petroleum flow standard.    

NMIJ is engaged in research on the standard for mass, one of the fundamental quantities, and R&D activities for measurement technology and measuring equipment related to force, torque (moment), pressure, vacuum and acceleration due to gravity. It is very important to ensure traceability of general measuring instruments to national standards in measurements of those quantities. For instance, traceability to be maintained should cover the Japanese copy of Prototype Kilogram weights and weighing instruments; force standards, force meters and uniaxial testing machines; and primary pressure standard and digital pressure gauges for pressure. We are also involved in research to establish and provide the national standards for torque, vacuum and acceleration due to gravity.    

Our research fields include super precision mass measuring technology, which we have realizedinvented to a level of 10^-10 using our vacuum balance, calibration technology to investigate the effects of microgravity gradientsfine gravity gradients, analysis of mass changes due to differences in environmental conditions of standards (weights), and investigation of the behavior of atoms and molecules on the surfaces of standard weights. In these programs, state-of-the-art analytical technology is brought into full play.     [ Mass and Force Standards Section ]

Aiming at the establishment of a national standard of torque at a precision of 10^-5 orders of magnitude, the NMIJ is devoted to development of two torque standard machines of dead weight type with a capacity of 1 kN·m and 20 kN·m, respectively. Research on the calibration method for torque measuring instruments is also being conducted.     [ Mass and Force Standards Section ]

Pressure is defined as the force applied over a unit area normal to the area. The Pressure and Vacuum Standards Section maintains and supplies gas pressure standards from 5 kPa to 7 MPa and liquid pressure standards from 1 MPa to 500 MPa. We also participate in international comparisons of various standards to ensure international consistency. R&D programs are also being conducted to further expand and improve the range of pressures to be standardized.     [ Pressure and Vacuum Standards Section ]

Medium and high vacuum (10^-7 Pa to 1 Pa) and standard leak flows (10^-11 to 10^-3 Pa/m3/s) are essential to state-of-the-art science and technology, such as semiconductor device manufacturing process. In order to establish national standards, we are engaged in research into technology for generating standard pressure fields, such as the expansion method or orifice method, standard leak standards, and vacuum measuring technology.     [ Pressure and Vacuum Standards Section ]

NMIJ is in charge of the establishment and dissemination of measurement standards and calibration service for flow rate, flow velocity and volume, and R&D of the related measuring technologies. We now have the national standard equipment for gas flow rate, water flow rate, and air speed to provide relevant calibration services. We also engage in R&D to expand the range of these calibration services and to enhance the reliability of the standards. The most recent news is that we have completed the world's finest-class national standard for hydrocarbon flow rate.    

An astronomical amount of money is handled in transactions using hydrocarbon flowmeters in today's modem society. It is therefore extremely important to provide a measurement standard at high precision. Aware of the need to satisfy such demand, the national standard for hydrocarbon flow rate was newly completed at the Tsukuba North Site. Designed to calibrate flowmeters for kerosene and light oil, this system realizes the world's smallest uncertainty with its high-precision diverter, unrivaled in the world.     [ Liquid Flow Standards Section ]

Low-gas-flow measurement plays a pivotal role in today's modern world, serving the semiconductor industry, on which our economy increasingly depends, and facilitating environmental measurement, whose importance is increasing year by year. The national standard for low-gas-flow, developed by the Fluid Flow Division, is designed to directly measure, using a super high precision balance, the mass of gas that flows into the measuring vessel. To realize and maintain this facility, a variety of advanced technologies are being introduced.     [ Gas Flow Standards Section ]

The national standard for low air speed is a tow carriage system installed in a 300-meter-long underground tunnel. Temperatures are kept very stable throughout the year in this underground tunnel, guaranteeing almost no air movement inside it. When the carriage runs through this atmosphere, the anemometer under calibration, loaded on the carriage, is exposed to air flow, whose speed is exactly equal to that of the carriage. This is the national standard created from the unprecedented idea of moving the anemometers, instead of the air. The calibration range is 0.05 m/s to 1.5 m/s.     [ Gas Flow Standards Section ]