English: A graph of the relative change in mass of selected kilogram prototypes. From The Third Periodic Verification of National Prototypes of the Kilogram (1988—1992), G. Girard, Metrologia 31 (1994) 317—336. The International Prototype Kilogram (IPK) kept in Sevres, France, and the other national prototype kilogram standards have been found to vary in mass over the years. Since the IPK defines the kilogram, the only way to detect changes in mass is to compare the mass of the prototypes, which is done every 40 years. This graph shows the "mass drift" of the numbered prototypes compared to the IPK.
The IPK is represented by the stylized K in an old-English typeface.
No. 39, which lost 665 µg relative to the IPK, had originally been allocated to Japan in 1894. In 1958, following the Second World War, it was ceded to the Republic of Korea.
No. 23 was allocated to Finland in 1890.
No. 8(41) was accidentally stamped with the number 41, but its accessories carry the proper number 8: since there is no prototype marked 8, this prototype is referred to as 8(41).
本圖片是以PNG、GIF或JPEG格式上傳。然而,其中包含的資料或訊息,應該重新建立成可縮放向量圖形(SVG)檔案,以更有效率或更準確的方式儲存。如有可能,請上傳本圖片的SVG格式版本。在上傳之後,請修改維基各姊妹計畫中所有使用舊版圖片的條目(列在圖像連結章節中),替換為新版圖片,並在舊圖片的描述頁中加入{{Vector version available|新圖片名稱.svg}}模板,同時移除本模板。
2007-12-10 04:22 Greg L 790×500× (194748 bytes) A graph of the relative change in mass of selected kilogram prototypes. From ''The Third Periodic Verification of National Prototypes of the Kilogram (1988â1992)'', G. Girard, Metrologia '''31''' (1994) 317â336
說明
添加單行說明來描述出檔案所代表的內容
A graph of the relative change in mass of selected kilogram prototypes,
{{BotMoveToCommons|en.wikipedia}} {{Information |Description={{en|A graph of the relative change in mass of selected kilogram prototypes. From ''The Third Periodic Verification of National Prototypes of the Kilogram (1988â1992)'', G. Girard,