About: http://webisa.webdatacommons.org/448263057

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	A chamfer is shown on the lower end of the field free tube 140; in the example shown in FIGS. 8A & 8B the chamfer is a surface at approximately 30 degrees to the X-Y plane, extending across the entire lower end of the tube.
http://www.w3.org/ns/prov#wasQuotedFrom	google.co.uk