PropertyValue
http://www.w3.org/1999/02/22-rdf-syntax-ns#type
http://www.w3.org/ns/prov#value
  • The effect of these compensations is to operationally provide essentially constant frequency and uniform phase throughout the AC power network. [0016] The AC power distribution frequency in the United States, Canada, Mexico and some other countries is 60 Hz and in some other countries is 50 Hz.
http://www.w3.org/ns/prov#wasQuotedFrom
  • google.com