<http://webisa.webdatacommons.org/prov/44841547>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/293521637> .
<http://webisa.webdatacommons.org/293521637>	<http://www.w3.org/ns/prov#value>	"Annular cover 261 preferably comprises a ceramic material, such as aluminum oxide or aluminum nitride, to shield the aluminum outer portion 255 of liner 250 from process gases and the heat within pumping channel 40." .
<http://webisa.webdatacommons.org/prov/297664218>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/293521637> .
<http://webisa.webdatacommons.org/293521637>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<google.com> .
<http://webisa.webdatacommons.org/293521637>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .