PMC:7796291 / 9272-9552 JSONTXT

{"project":"LitCovid-sentences","denotations":[{"id":"T83","span":{"begin":94,"end":229},"obj":"Sentence"},{"id":"T84","span":{"begin":231,"end":235},"obj":"Sentence"},{"id":"T85","span":{"begin":236,"end":251},"obj":"Sentence"}],"namespaces":[{"prefix":"_base","uri":"http://pubannotation.org/ontology/tao.owl#"}],"text":"atic voltmeter (Model 542A, Trek, Lockport, NY, USA), by holding the filter media in the air. A charge-monitoring probe was placed 4 cm above the web surface, and the surface potential was measured by line-scanning over the area.\n\n2.4. Filtration Test\nThe filtration performance o"}