About: http://webisa.webdatacommons.org/339523426

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	As an alternative, cavities made of materials such as ultra-pure Al and Be, which become very good ???but not super??? conductors at cryogenic temperatures, can be used.
http://www.w3.org/ns/prov#wasQuotedFrom	osti.gov