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| Категории верхнего уровня |
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| Криптон (@1882) |
| Krypton [Анг.] |
(Gr. kryptos: hidden) Discovered in 1898 by Ramsay and Travers in the residue left after liquid air had nearly boiled away. In 1960 it was internationally agreed that the fundamental unit of length, the meter, should be defined in terms of the orange-red spectral line of 86Kr. This replaced the standard meter of Paris, which was defined in terms of a bar made of a platinum-iridium alloy. In October 1983, the meter, which originally was defined as being one ten millionth of a quadrant of the earth's polar circumference, was again redefined by the International Bureau of Weights and Measures as being the length of a path traveled by light in a vacuum during a time interval of 1/299,792,458 of a second.
A Periodic Table of the Elements at Los Alamos National Laboratory |
| Тип: Объект |
| Относится к разделам: |
| / Вещество / Химические элементы |
| / Физика / Оптика / Спектроскопия |
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