| 释义 |
paraxial, a.|pəˈræksɪəl|
[f. para-1 1 + L. axi-s axis: cf. axial.]
a. Anat. and Zool. Lying alongside, or on each side of, the axis of the body.
1861J. R. Greene Man. Anim. Kingd., Cœlent. 228 The oral extremities of the paraxial canal system. 1870Nicholson Man. Zool. 113 The ‘paraxial system’, comprising the paragastric canals. 1893Syd. Soc. Lex., Paraxial muscles, the muscles developed by the side of the vertebral column.
b. Optics. Situated close to the axis of an optical system, and (if linear) virtually parallel to it; of or pertaining to such a region.
1906H. D. Taylor Syst. Appl. Optics iv. 55 The ultimate or paraxial rays. 1930L. C. Martin Introd. Appl. Optics I. i. 17 Imagine..that the point P is brought so close to the axis that the inclination of the ray to the axis becomes very small; these conditions are characteristic of a ‘paraxial’ ray. 1934W. H. A. Fincham Optics v. 83 For light in the paraxial region the angles of incidence and refraction will be very small, and may be considered as proportional to their sines in applying the law of refraction. 1974W. T. Welford Aberrations Symmetr. Optical Systems iii. 17 We..define the domain of paraxial or Gaussian optics to be close enough to the axis to ensure that all terms of higher order of magnitude than quadratic in x and y are to be neglected.
Hence paˈraxially adv., adjacent to or virtually parallel to an axis.
The 1905 reference given in quot. 1909 is incorrect and has not been traced.
1909Cent. Dict. Suppl., Paraxially, in zoöl., in such a way as to lie on each side of the long axis (of the body). Proc. Roy. Soc. (London), Feb., 1905, p. 318. 1927V. T. Saunders Light iii. 38 If a single ray is incident on the mirror through the principal focus it is seen to be reflected paraxially. 1950H. H. Hopkins Wave Theory of Aberrations 162 The paraxial equations..refer to rays which are limitingly close to the axis. Since, however, the equations are linear in the angles u, a, i rays at finite apertures may be traced paraxially. |