An on-site comparison of the quantum Hall effect (QHE) resistance standards of the National Institute of Standards and Technology (NIST) and of the Bureau International des Poids et Mesures (BIPM) was made in April 1999. Measurements of a 100 0 standard in terms of the conventional value of the von Klitzing constant, RK-90, agreed to 12 parts in 101.0with a relative combined standard uncertainty 1Lc= 20 X 10-10. Measurements of 10000 0/100 nand 100 0/1 0 ratios agreed to 59 parts in 1010 with 1Lc= 55 X 10-10 and to 38 parts in 1010 with 1Lc = 31 X 10-10, respectively.

No abstract

No abstract

No abstract

No abstract