About: http://webisa.webdatacommons.org/374062027

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	Various apparatus for placing such masks or mask portions in the path of a beam of radiation are known in the art, and FIG. 1 schematically illustrates such as apparatus.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com