منابع مشابه
Hysteresis and Related Error Mechanisms in the NIST Watt Balance Experiment
The NIST watt balance experiment is being completely rebuilt after its 1998 determination of the Planck constant. That measurement yielded a result with an approximately 1×10(-7) relative standard uncertainty. Because the goal of the new incarnation of the experiment is a ten-fold decrease in uncertainty, it has been necessary to reexamine many sources of systematic error. Hysteresis effects ac...
متن کاملThe new METAS Watt Balance, Mark II
In the context of the future new definition of the mass unit, kg, a promising route to link the mass unit to a fundamental constant, the Planck constant h, is represented by the watt balance experiment. Since a number of years, the Federal Institute of Metrology is active in this field and published a first result with its Mark I experiment in 2011. To reach the target uncertainty of 2 parts in...
متن کاملThe New Watt Balance Experiment at Metas
The kilogram is the last unit of the international system (SI) still based on a material artifact, the international prototype of the kilogram (IPK). The comparisons made in the last hundred years have clearly revealed a long term relative drift between the IPK and a set of copies kept under similar conditions. Since the long term stability is one of the major conditions set on the SI base unit...
متن کاملFabrication of the Magnetic Circuit for the Bipm Watt Balance
INTRODUCTION Since 1889 the International Prototype of the Kilogram, kept at the BIPM, had served as the definition of the unit of mass in the International System of Units (SI). It is the last material artefact to define a base unit of the SI, and it influences several other base units. This situation is no longer adequate in a time of ever increasing measurement precision. It is therefore pla...
متن کاملDetermination of the Planck constant with the METAS watt balance
The METAS watt balance project was initiated slightly more than a decade ago. Over this time, the apparatus has been through an uninterrupted series of upgrades that have improved its reliability to a point where continuous series of measurements can be taken fully automatically over periods of several months. A comprehensive analysis of possible systematic errors has now been completed and a l...
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ژورنال
عنوان ژورنال: IEEE Transactions on Instrumentation and Measurement
سال: 1996
ISSN: 0018-9456
DOI: 10.1109/19.492750