| 单词 | radium etc emanation |
| 释义 | > as lemmasradium etc. emanation c. Chemistry. A radioactive gas produced by the radioactive decay of a solid; spec. any of the three gases radon, actinon, and thoron produced respectively by radium, actinium, and thorium (so radium etc. emanation); also used as a name for the element radon, of which these gases are now known to be isotopes. ΚΠ 1900 Rutherford in London, Edinb. & Dublin Philos. Mag. 49 1 I have found that thorium compounds continuously emit radio-active particles of some kind, which retain their radio-active powers for several minutes. This ‘emanation’, as it will be termed for shortness, has the power.. of passing through thin layers of metals. 1903 Daily Chron. 27 Nov. 8/3 He [Sir W. Ramsay] pointed out that the thorium emanations were an ephemeral gas which in two minutes ceased to exist. 1906 E. Rutherford Radioactive Transformations iii. 72 A large quantity of emanation was introduced into a glass tube..and the ionization due to the issuing rays was measured. 1907 Athenæum 31 Aug. 244/2 Thorium..gives no fewer than seven radio-active products, in the following order: mesothorium, radiothorium, thorium X, thorium emanation, and thorium A, B, and C. 1927 N. V. Sidgwick Electronic Theory of Valency iii. 29 The names radon, thoron, and actinon are now accepted for the three isotopic emanations. It is desirable that there should be some name for element no. 86 irrespective of any particular isotope, and I have retained the name emanation (with the symbol Em) for this purpose. 1940 S. Glasstone Text-bk. Physical Chem. ii. 125 The emanations, particularly that from actinium, lost their activity relatively rapidly. 1950 S. Glasstone Sourcebk. Atomic Energy v. 116/2 The production of a gaseous emanation provides a convenient means of separating this radioactive species from those which precede it in the disintegration series. 1957 Encycl. Brit. XVII. 882 b/1 There are six elements collectively known as the inert gases... Their atomic numbers and their names are: 2 Helium, 10 Neon, 18 Argon, 36 Krypton, 54 Xenon, 86 Emanation. 1964 J. R. Partington Hist. Chem. IV. xxvii. 941 Some doubts about the existence of radium emanation were removed by Rutherford and Soddy, who liquefied it by cooling in liquid air. < as lemmas |
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