Lêer:US radium standard 1927.jpg
Grootte van hierdie voorskou: 800 × 415 piksels. Ander resolusies: 320 × 166 piksels | 640 × 332 piksels | 1 222 × 634 piksels.
Oorspronklike lêer (1 222 × 634 piksels, lêergrootte: 171 KG, MIME-tipe: image/jpeg)
Opsomming
| Beskrywing |
English: Sealed glass tube of radium chloride kept by the US Bureau of Standards that served as the primary standard of radioactivity for the United States in 1927, and several subsidiary working standards. . This was officially known as the "Secondary radium standard no. 6" which had in 1913 been calibrated against the International Radium Standard, a similar tube of radium chloride prepared by Marie Curie, kept by the Bureau Internationale des Poids et Measures (International Bureau of Weights and Measures) at Sevres, France. This was determined to contain 20.68 mg of radium chloride, corresponding to 15.44 mg of radium in 1913. Since radium decays at a rate of about 1% in 25 years, at the time of this picture it was estimated to contain 15.360 mg of radium |
| Datum | |
| Bron | Retrieved January 19, 2014 from Standards Yearbook 1927, US National Bureau of Standards, Dept. of Commerce, printed by US Government Printing Office, Washington D.C., p. 399, fig. 30 on Google Books |
| Outeur | George K. Burgess, Director, US National Bureau of Standards |
Lisensiëring
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This work is in the public domain in the United States because it is a work prepared by an officer or employee of the United States Government as part of that person’s official duties under the terms of Title 17, Chapter 1, Section 105 of the US Code.
Note: This only applies to original works of the Federal Government and not to the work of any individual U.S. state, territory, commonwealth, county, municipality, or any other subdivision. This template also does not apply to postage stamp designs published by the United States Postal Service since 1978. (See § 313.6(C)(1) of Compendium of U.S. Copyright Office Practices). It also does not apply to certain US coins; see The US Mint Terms of Use.
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| Datum/Tyd | Duimnael | Dimensies | Gebruiker | Opmerking | |
|---|---|---|---|---|---|
| huidig | 10:55, 7 Oktober 2015 | | 1 222 × 634 (171 KG) | Chetvorno | User created page with UploadWizard |
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