| 单词 | dark line |
| 释义 | > as lemmasdark line dark line n. a line of relative darkness in the spectrum of light coming from a given source, caused by absorption of light at a particular wavelength; = absorption line n. at absorption n. Compounds 2; often in plural or as a modifier.Cf. bright line n. 1, Fraunhofer lines n. at Fraunhofer n. ΘΚΠ the world > matter > physics > atomic physics > decomposition of light, spectrum > [noun] > system of absorption bands > dark lines of dark line1802 absorption line1861 1802 W. H. Wollaston in Philos. Trans. (Royal Soc.) 92 ii. 378 C, the limit of green and blue, is not so clearly marked as the rest; and there are also, on each side of this limit, other distinct dark lines. 1890 C. A. Young Elem. Astron. vi. §207 The characteristic feature of the visual spectrum [of the sun's corona] is a bright line in the green... It coincides with a dark line..on Kirchhoff's map of the solar spectrum. 1928 W. M. Smart Sun, Stars & Universe vi. 83 Certain groups of lines which are known to belong to the arc spectra of the elements concerned..together with their dark-line counterparts in the solar spectrum. 2017 Guardian (Nexis) 5 Jan. (Books section) The photographs could, with the use of diffraction gratings, yield stellar spectra striated by those characteristic dark lines that are the signatures of various elements. < as lemmas |
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