| 释义 |
nodal, a.|ˈnəʊdəl|
[f. node n. + -al1; cf. F. nodal.]
Pertaining to, of the nature of, a node or nodes, in various senses, esp.
1. nodal line or nodal point, a line or point of absolute or comparative rest in a vibrating body or surface. Similarly nodal surface. Cf. node n. 6 a.
1831Faraday Exp. Res. xlvi. 318 Neither sand nor filings could rest on the quiescent, or nodal, lines. 1838in Eng. Mech. (1869) 24 Dec. 356/3 It was situated at a nodal or quiescent point during some tones. 1873W. Lees Acoustics i. iii. 25 We have not only nodal points in a vibrating string, but we may have nodal lines in a vibrating plate. 1937J. W. T. Spinks tr. Herzberg's Atomic Spectra & Atomic Struct. i. 41 For n > 1, ψ goes once, or more than once, through the value zero before the exponential decrease sets in; that is, on certain spherical surfaces about the nucleus, the ψ function is always zero. These are the nodal surfaces of the ψ function corresponding to the nodes of a vibrating string.
2. Bot. and Biol. Pertaining to, of the nature of, a node in a vegetable or animal organism.
1842Willshire in Ann. Nat. Hist. IX. 85, I have examined portions of the plant both young and old, and at all portions of the nodal places. 1875Huxley & Dyer in Encycl. Brit. III. 683/1 An inter-nodal cell, which elongates greatly,..is succeeded by a nodal cell, which elongates but little. 1882Vines tr. Sachs' Bot. 191 Each nodal disk consists of the anterior half of an older segment [etc.]. 1888Rolleston & Jackson Anim. Life 572 The cirri are borne..upon certain joints of the stem, hence termed nodal.
3. nodal point, a stopping- or starting-point; a centre of convergence or divergence; a point constituting a node of any kind.
1845Grove Contrib. to Sci. 298 Forming the nodal point or zero of the table. 1862M. Hopkins Hawaii 238 These nodal points [in history] determine the length of his chapters. 1863Dana Man. Geol. 598 These species occupy nodal points, as they may be called, or points of divarication. 1880Le Conte Sight 29 This point of ray-crossing is called the nodal point.
4. Astron. Pertaining to planetary nodes.
1868Lockyer Guillemin's Heavens (ed. 3) 220 It is enough to look out for the body at one or other of these nodal passages. 1872Proctor Ess. Astron. ix. 125 The nodal shifting of the meteor-band. |