| 释义 |
nuˈtate, v.
[f. ppl. stem of L. nūtāre: cf. nutant a.]
intr. To undergo or exhibit nutation. Hence nuˈtating ppl. a.
1880C. & F. Darwin Movem. Pl. 99 He has shewn in the case of certain seedlings, whose tips are bent downwards (or which nutate), that [etc.]. 1881Spectator 8 Jan. 51 That side of the nutating stem..faces the north throughout the movement. 1897Willis Fl. Pl. & Ferns I. 174 The nutating tip of a twining stem. 1898S. H. Vives Elem. Text-bk. Bot. iii. 211 All growing members nutate in a more or less marked manner. 1921J. Small Textbk. Bot. xvii. 221 In the mature plant the top three internodes of the stem turn or nutate in a circle. 1943R. C. Binder Fluid Mech. viii. 107 The nutating-disk meter or wobble-plate meter..is frequently used to meter the water supply for domestic use. 1948C. E. Ingalls in S. N. Van Voorhis Microwave Receivers xv. 380 Tracking in azimuth and elevation is made possible by the use of a nutating antenna. A fixed paraboloidal reflector is combined with a dipole, which is caused to move in a small circular orbit about the focus of the reflector, to give a radiation pattern in the form of a beam that traces out a small cone. 1950H. Goldstein Class. Mech. v. 168 It is not the regular precession encountered in force-free motion, for as the figure axis goes around it nods up and down..—the top nutates. 1965Bell & Coombe tr. Strasburger's Textbk. Bot. 390 A nutating shoot. 1969R. Skinner Mech. iv. 469 The top continues to spin about its axis of symmetry, while this axis rotates, or precesses, about a vertical axis. All the while, this axis [of symmetry] nods up and down, or nutates, as it precesses. |