| 单词 | mean lifetime |
| 释义 | > as lemmasmean lifetime b. Physics. Also mean lifetime. The average duration of existence of the members of an exponentially decaying population of identical particles or states (equal to the period in which the population decreases by a factor of e). Cf. half-life n. 2a, life n. 10b. ΘΚΠ the world > matter > physics > atomic nucleus > radioactive isotope > radioactive nuclide > [noun] > average duration life1903 mean lifetime1909 1909 Munsey's Mag. 41 399/2 The actual lifetime of radium is unknown, but after fifteen hundred years only half of the original mass would remain. 1939 Physical Rev. 55 506/1 The lifetime for a mesotron at rest has been estimated..to be of the order 2−4 × 10−6 sec. 1950 Physical Rev. 77 153/1 (heading) Lifetimes of mercury and potassium atoms in excited states. 1973 L. J. Tassie Physics Elem. Particles vi. 51 A typical strange particle is the Λ°, an uncharged particle which decays with a mean lifetime of 2·5 × 10−10 s. 1993 New Scientist 13 Mar. 41/2 Particle physicists are also interested in this quantity [sc. half-life], but for historical reasons they talk in terms of a related number called the lifetime, which is the time it takes for the number of particles in the original sample to reduce to 1/e of their original number. 2002 F. Close et al. Particle Odyssey viii. 150 Nowadays, almost every experiment has a silicon ‘vertex’ detector, which can reveal the ‘vertices’ where tracks diverge as short-lived particles decay to those with longer lifetimes. < as lemmas |
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