About: http://webisa.webdatacommons.org/366082238

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 illustrated in Fig. 5(a), metals such as aluminum, gold and silver all have a negative electric permittivity at optical frequencies.
http://www.w3.org/ns/prov#wasQuotedFrom	opticsinfobase.org