| 单词 | negative crystal |
| 释义 | > as lemmasnegative crystal negative crystal n. (a) Optics a crystal in which the index of refraction is greater for the ordinary than the extraordinary ray; (b) Geology a cavity having the shape of a crystal within a mineral mass. ΘΚΠ the world > the earth > minerals > mineral structure or appearance > [noun] > cavity cell1665 negative crystal1831 glass-cavity1857 the world > matter > chemistry > crystallography (general) > crystal (general) > crystal types > [noun] negative crystal1831 plastic crystal1877 liquid crystal1891 cholesteric1965 mesomorph1969 1831 D. Brewster Treat. Optics xxii. 196 Those produced by the positive crystals..though to the eye they differ in no respect from those of negative crystals, yet they possess different properties. 1839 G. Bird Elements Nat. Philos. 354 In negative crystals, as Iceland spar, the direction of these rays is reversed. 1882 A. Geikie Text-bk. Geol. 96 Such a space defined by crystallographic contours is a negative crystal. 1895 A. Harker Petrol. ii. 26 These [sc. fluid-cavities] are sometimes in the form of ‘negative crystals’, either dihexahedral pyramids or elongated prisms. 1968 I. Kostov Mineral. 500 Slavikite is trigonal, found in minute uniaxial negative crystals tabular on {0001}. 1995 Mineral. Mag. 59 5 Microinclusions with the corroded olivines generally have subspherical/ellipsoidal shapes with boundaries modified to a subplanar ‘negative crystal’-like outline. < as lemmas |
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