| 单词 | numerical aperture |
| 释义 | > as lemmasnumerical aperture numerical aperture n. a measure of the resolving power of a microscope objective (for a given wavelength), equal to the product of the refractive index of the medium in front of it and the sine of the semi-angle of the cone it subtends at the centre of the object. ΚΠ 1878 Jrnl. Royal Microsc. Soc. 1 19 The inner scale shows the air-angle, the outer scale the ‘numerical aperture’. 1952 R. W. Ditchburn Light viii. 253 Higher magnifications have been obtained using electron microscopes... The effective wavelength may be of the order of 0·1 Å., but the numerical aperture of models so far available is very low, being only of the order of 0·01. 1988 M. Tucker Techniques in Sedimentol. (BNC) 178 He found that the controlling factors were the magnifications and numerical apertures of eyepieces and objectives, transmission of individual optical elements, and other details of the optical path. < as lemmas |
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