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Standards of lenght and time / J. Terrien in Reports on progress in physics, vol 39 n° 11 ([01/11/1976])  

Public [article]  inReports on progress in physics > vol 39 n° 11 [01/11/1976] . - pp 1067 - 1108 Titre : Standards of lenght and time Type de document : Article/Communication Auteurs : J. Terrien, Auteur Année de publication : 1976 Article en page(s) : pp 1067 - 1108 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Métrologie [Termes IGN] électronique [Termes IGN] étalon [Termes IGN] longueur [Termes IGN] temps Résumé : (auteur) The Pt-Ir bar, international prototype of the metre, was one hundred times less precise as a length standard than the orange line of 86Kr by which the metre has been defined since 1960. Molecular absorption lines which happen to coincide with gas laser radiations are being studied, two of which now have their wavelengths agreed internationally to serve as standards one hundred times more precise than the Kr radiation. The present time standard is the period of oscillation of the radiation corresponding to a hyperfine transition in 133Cs on which the definition of the second has been based since 1967, the preceding definitions based on the year (adopted in 1956) and on the mean solar day (before 1956) being 104 and 106 times less precise. Ways to further increase the precision and accuracy of these and other types of frequency standards as well as values for the speed of light, are discussed. Numéro de notice : A1976-057 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1088/0034-4885/39/11/002 En ligne : https://doi.org/10.1088/0034-4885/39/11/002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=34302 [article]

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Code-barres	Cote	Support	Localisation	Section	Disponibilité
54468-01	24.40	Tiré à part	Centre de documentation	Physique	Disponible