| 释义 |
concentric, a. (and n.)|kənˈsɛntrɪk|
Also 4 -sentrik, -sentryk, 7 -centrique.
[ad. F. concentrique, or med.L. concentric-us (14th c. in Du Cange), f. con- together + centr-um circle: cf. centric, eccentric, the ultimate type being Gr. κεντρικός, of the centre, central.]
A. adj.
1. Having a common centre, described about the same centre. (Said of circles and spheres, etc.)
c1391Chaucer Astrol. i. §16 Degres of this Bordure ben answering & consentrik to the degrees of the Equynoxial. Ibid. i. 17 The heued of capricorne turnyth euermo consentryk vp-on the same cercle. 1621Burton Anat. Mel. ii. ii. iii. (1676) 159/2 Real Orbes, eccentrick, concentrick, etc. 1692Bentley Boyle Lect. viii. 266 The concentric Revolutions of the Planets about the Sun. 1706Sibbald Hist. Picts in Misc. Scot. I. 105 An inner wall, concentric with, and distant about two feet from the other. 1726tr. Gregory's Astron. I. 3 Not perfect Circles, concentric to the Sun. 1808Asiat. Res. VIII. 289 The Baudd'hists of Tibet represent these zones as so many concentric squares. 1880G. Allen in Mind V. 451 A gradual regression or concentric widening of æsthetic feeling around this fixed point.
fig.1603Daniel Epist. Wks. (1717) 350 It hath a Course Concentrick, with the Universal Frame Of Men combin'd. a1711Ken Hymnarium Poet. Wks. 1721 II. 75 Till my will mov'd concentrick with thy own. 1871Tyndall Fragm. Sc. (ed. 6) II. ii. 29 Not until this..is the law of reason rendered concentric with the law of nature.
2. Specific uses.
a. Bot., as in concentric bundle: a fibro-vascular bundle in which the bast tissue surrounds the wood tissue, or vice versa. (Opposed to collateral.)
1878McNab Bot. (ed. 4) 45 In the ferns and lycopods, and in some monocotyledons, where the phloem completely surrounds the xylem the bundles may be called concentric. 1884Bower & Scott De Bary's Phaner 467 The number of the concentric cambium-like layers varies.
b. Conch. (See quot.)
1854Woodward Mollusca (1856) 102 The operculum is..Concentric, when it increases equally all round. 1866Tate Brit. Mollusks iii. 46 Its mode of growth is concentric.
c. Biol. etc.
concentric cells: ‘cells which contain another cell’. concentric contraction: ‘a muscular contraction which results in the approximation of the two ends, and the consequent shortening, of the muscle’. concentric differentiation: ‘that process by which, when any organic or inorganic substance exerts a play of forces with the surrounding medium, the superficial differ from the deeper parts’ (Syd. Soc. Lex.).
d. Geol. and Min. concentric structure: a structure in which parallel layers, differing in colour or composition, lie round a common centre.
1811Pinkerton Petral. I. 223 If the kernels..retain their uniform concentric tints. 1842H. Miller O.R. Sandst. xiii. (ed. 2) 281 Their concentric condition shows the chemical influences of the decaying animal matter.
e. Mil. concentric fire: firing concentrated on one point.
1850Alison Hist. Europe VIII. li. §62. 524 The severity of the concentric discharges was so great that this gallant regiment wavered and broke. 1852Blackw. Mag. LXXII. 355 Subject every day to the concentric fire of the Radical press. 1875tr. Comte de Paris' Civil War Amer. II. 348 [The brigade] soon found itself exposed to a concentric fire.
f. Pathol. concentric hypertrophy: A term applied to hypertrophy of the heart when the cavities are smaller than natural.
1871Sir T. Watson Princ. & Pract. Phys. II. 270. 1876 tr. Ziemssen's Cycl. VI. 211.
g. Electr. concentric cable = coaxial cable. So concentric main.
1892J. A. Fleming Altern. Curr. Transf. II. 151 Simple straight-joint coupling in Siemens and Halske concentric cable. Ibid. 316 Mr. Ferranti designed for the London Electric Supply Corporation a form of concentric main, intended for extra high-pressure service. 1944Electronic Engin. XVI. 403 Linking with the provinces would be possible by concentric cable.
h. Photogr. concentric lens, a symmetrical doublet lens of two combinations, the surfaces of which are spherical and concentric.
1892Brit. Jrnl. Photogr. 29 Apr. 273/1 We have on previous occasions spoken of a patent new ‘concentric’ lens. 1902Encycl. Brit. XXXI. 695/1 The first lens made with the new glasses was Dr. Schroeder's ‘Concentric’. 1918Photo-Miniature XV. 12 Concentric, the name given to an anastigmat lens, the radii of the back and front surfaces of each element of which were struck from a common condenser. 1958Ilford Man. Photogr. (ed. 5) viii. 132 The peculiarity of the Concentric was the use of plano-convex crowns, and the fact that the exposed surfaces were concentric.
†3. catachr. = concentrated 2. Obs. rare—1.
1771Phil. Trans. LXI. 340 Acids never are given in so concentric a state.
B. n. A concentric circle or other figure.
1551Recorde Pathw. Knowl. i. Concentrikes, that is to saie, circles drawen on one centre. 1603Florio Montaigne ii. xii. (1632) 301 These Epicycles, Excentriques, and Concentriques, which Astrology useth. a1656Hales Gold. Rem. (1688) 358 Such Concentricks or Epicycles of Sympathies and Antipathies. |