CINF 20 |
| The Consultative Committee for Units (CCU) advised the 23rd General Conference on Weights and Measures (CGPM, Sept 2007) that new definitions be adopted for the kilogram, ampere, kelvin and mole to fix the values of h, e, k and NA respectively. Reports from numerous bodies were taken into consideration for this recommendation, including the Consultative Committee for Electricity and Magnetism (CCEM) that unambiguously supports redefining the kilogram to fix h and the ampere to fix e. Their primary argument for this change is that it would bring electrical metrology, which is now universally based on the use of the Josephson effect to measure electrical potential difference and the quantum Hall effect to measure electrical resistance, into line with the SI, through the use of defined values for e and h in the relations KJ = 2e/h for the Josephson constant and RK = h/e2 for the von Klitzing constant. Use of these quantum electrical standards to realize the new definition of the SI unit of mass via a watt balance, known as the “electronic kilogram,” and the implications for the base unit of mole will be discussed. |
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Past, Present and Future of the Kilogram
3:30 PM-5:10 PM, Sunday, April 6, 2008 Marriott Convention Center -- Blaine Kern C, Oral
Division of Chemical Information |