{"?xml":{"@version":"1.0"},"edm:RDF":{"@xmlns:dc":"http://purl.org/dc/elements/1.1/","@xmlns:edm":"http://www.europeana.eu/schemas/edm/","@xmlns:wgs84_pos":"http://www.w3.org/2003/01/geo/wgs84_pos","@xmlns:foaf":"http://xmlns.com/foaf/0.1/","@xmlns:rdaGr2":"http://rdvocab.info/ElementsGr2","@xmlns:oai":"http://www.openarchives.org/OAI/2.0/","@xmlns:owl":"http://www.w3.org/2002/07/owl#","@xmlns:rdf":"http://www.w3.org/1999/02/22-rdf-syntax-ns#","@xmlns:ore":"http://www.openarchives.org/ore/terms/","@xmlns:skos":"http://www.w3.org/2004/02/skos/core#","@xmlns:dcterms":"http://purl.org/dc/terms/","edm:WebResource":[{"@rdf:about":"http://www.dlib.si/stream/URN:NBN:SI:DOC-T7TW8V80/5fd94771-00dd-4da3-a473-7fa807adb456/HTML","dcterms:extent":"22 KB"},{"@rdf:about":"http://www.dlib.si/stream/URN:NBN:SI:DOC-T7TW8V80/2b093102-cb30-4ae0-ad15-38aacca2ec60/PDF","dcterms:extent":"252 KB"},{"@rdf:about":"http://www.dlib.si/stream/URN:NBN:SI:DOC-T7TW8V80/9d7401b8-9925-41bb-826d-5357c2773867/TEXT","dcterms:extent":"20 KB"}],"edm:TimeSpan":{"@rdf:about":"2000-2024","edm:begin":{"@xml:lang":"en","#text":"2000"},"edm:end":{"@xml:lang":"en","#text":"2024"}},"edm:ProvidedCHO":{"@rdf:about":"URN:NBN:SI:DOC-T7TW8V80","dcterms:isPartOf":[{"@rdf:resource":"https://www.dlib.si/details/urn:nbn:si:spr-ihg6vo21"},{"@xml:lang":"sl","#text":"Materiali in tehnologije"}],"dcterms:issued":"2007","dc:creator":"Šetina, Janez","dc:format":[{"@xml:lang":"sl","#text":"številka:3"},{"@xml:lang":"sl","#text":"letnik:41"},{"@xml:lang":"sl","#text":"5 strani"},{"@xml:lang":"sl","#text":"str. 145-149"}],"dc:identifier":["ISSN:1580-2949","COBISSID:607402","URN:URN:NBN:SI:doc-T7TW8V80"],"dc:language":"sl","dc:publisher":{"@xml:lang":"sl","#text":"Inštitut za kovinske materiale in tehnologije"},"dc:subject":[{"@xml:lang":"sl","#text":"merjenje"},{"@xml:lang":"sl","#text":"trenje"},{"@xml:lang":"sl","#text":"vakuum"},{"@xml:lang":"sl","#text":"vakuumski merilnik"},{"@rdf:resource":"http://www.wikidata.org/entity/Q82580"}],"dcterms:temporal":{"@rdf:resource":"2000-2024"},"dc:title":{"@xml:lang":"sl","#text":"Frekvenčna odvisnost rezidualnega trenja viskoznostnega vakuumskega merilnika z lebdečo kroglico| Frequency dependence of spinning rotor gauge residual drag|"},"dc:description":[{"@xml:lang":"sl","#text":"Spinning rotor gauge (SRG) is well recognized in the field of low pressure metrology as precise and stable reference standard in the range from 10-4 Pa to 1 Pa. The achievable measurement uncertainty of commercial SRG is 0,5%, assuring a suitable calibration with a higher level primary standard. Important correction of SRG is the pressure independent contribution to the measured signal known as residual drag. It is caused by eddy current losses in magnetic levitation system and metallic parts in the close vicinity of the spinning rotor, and can be determined at very low gas pressure as a zero signal of the gauge. The residual drag usually depends on the rotational frequency of the rotor. It can be approximated with a linear function which can be determined by linear regression of measured values as a function of rotational frequency. We have investigated stability and frequency dependence of residual drag for several different suspensions of two SRG rotors. Results showed that there is no correlation between frequency dependence and magnitude of residual drag. The frequency dependence is in most cases large enough to have significant influence on the measurements and has to be taken into account for precise pressure measurements below 1 10-3 Pa"},{"@xml:lang":"sl","#text":"Viskoznostni merilnik tlaka z lebdečo kroglico (SRG - Spinning Rotor Gauge) seje uveljavil v meroslovju nizkih tlakov kot precizen in stabilen referenčni etalon za območje med 10-4 Pa in 1 Pa. Ob ustrezni kalibraciji s primarnimi vakuumskimi standardi je v tem območju tlakov dosegljiva merilna negotovost pri komercialnih merilnikih 0,5 %. Med vplivnimi veličinami pri merjenjih z SRG-merilnikom je najpomembnejše rezidualno trenje rotorja, ki se pojavi zaradi vrtinčnih električnih izgub pri magnetnem lebdenju in vrtenju kroglice. Rezidualno trenje lahko izmerimo pri zelo nizkem tlaku kot ničelni signal in ga nato upoštevamo pri meritvi tlaka kot popravek. Časovna stabilnost rezidualnega trenja določa spodnjo merilno mejo SRG-merilnika. Izkaže se, da je rezidualno trenje odvisno od frekvence vrtenja rotorja. Frekvenčno odvisnost lahko določimo z linearno regresijo merjenih vrednosti rezidualnega trenja v odvisnosti od frekvence. Podrobneje smo raziskali stabilnost in frekvenčno odvisnost rezidualnega trenja pri različnih namestitvah dveh kroglic. Rezultati so pokazali, da je frekvenčna odvisnost slabo korelirana z absolutno vrednostjo rezidualnega trenja. V večini primerov je frekvenčna odvisnost tako velika, da jo moramo upoštevati pri izračunu popravka rezidualnega trenja pri meritvah tlakov plina pod 1 10-3 Pa"}],"edm:type":"TEXT","dc:type":[{"@xml:lang":"sl","#text":"znanstveno časopisje"},{"@xml:lang":"en","#text":"journals"},{"@rdf:resource":"http://www.wikidata.org/entity/Q361785"}]},"ore:Aggregation":{"@rdf:about":"http://www.dlib.si/?URN=URN:NBN:SI:DOC-T7TW8V80","edm:aggregatedCHO":{"@rdf:resource":"URN:NBN:SI:DOC-T7TW8V80"},"edm:isShownBy":{"@rdf:resource":"http://www.dlib.si/stream/URN:NBN:SI:DOC-T7TW8V80/2b093102-cb30-4ae0-ad15-38aacca2ec60/PDF"},"edm:rights":{"@rdf:resource":"http://rightsstatements.org/vocab/InC/1.0/"},"edm:provider":"Slovenian National E-content Aggregator","edm:intermediateProvider":{"@xml:lang":"en","#text":"National and University Library of Slovenia"},"edm:dataProvider":{"@xml:lang":"sl","#text":"Inštitut za kovinske materiale in tehnologije"},"edm:object":{"@rdf:resource":"http://www.dlib.si/streamdb/URN:NBN:SI:DOC-T7TW8V80/maxi/edm"},"edm:isShownAt":{"@rdf:resource":"http://www.dlib.si/details/URN:NBN:SI:DOC-T7TW8V80"}}}}