About: http://webisa.webdatacommons.org/238225747

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	Helium is the preferred pulse tube gas; however any effective working gas may be used in a pulse tube refrigerator and among such one can name nitrogen, oxygen, argon and neon, or mixtures containing one or more thereof such as air.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com