NNR IN RAPIDLY ROTATED METALS By - Nottingham eTheses ...

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rate of 6 kHz. Higher speeds were achieved by using helium.
The rotors would spin at all frequencies down to 20 Hz and were
largely unaffected by altering the clearance between the rotor
and the bearing: characteristics which were remarkably different
from the original system.
The sample-carrying capacity of the Prague rotor system is
inferior to the conical and foil bearing rotors. The only
obvious advantage of the rotors produced in the laboratory was
their stable operation at very low frequencies. As this is not
a normal requirement of an NMR system, work was discontinued on
this type of rotor in favour of the foil-bearing design.