| 释义 |
▪ I. radius, n.|ˈreɪdɪəs|
Also 7 -ous. Pl. radii |ˈreɪdɪaɪ|; also 7–8 radius's, 8 -uses.
[a. L. radius a staff or stake, measuring-rod, spoke, ray, etc. (cf. senses below).]
1. A staff, rod, bar, or other straight object.
†a. The staff of a cross; hence Astron. a cross-staff. Obs.
1597Morley Introd. Mus. 174 The Radius or staffe of the crosse containeth like wise two partes in one. [1727–41Chambers Cycl. s.v., Radius astronomicus, an instrument usually called Jacob's staff, or the cross-staff.] 1742Young Nt. Th. ix. 646 With my Radius (the rich Gift Of Thought nocturnal!) I'll point out to thee Its various Lessons.
†b. The bony spine or sting near the base of the tail of a sting-ray. Obs. rare—1.
1661Lovell Hist. Anim. & Min. 201 Fork-fish... Their Radius only is poysonsome, which being cut off, the rosted may be eaten.
c. Anat. The thicker and shorter of the two bones of the forearm in man, extending from the humerus to the thumb side of the wrist; also the corresponding bone of the foreleg in quadrupeds, and of the wing in birds.
The name has also been given to a bone of the pectoral arch in fishes, held to be homologous with the radius of higher vertebrates.
1615Crooke Body of Man (1618) 782 The whole hand being sustained almost alone by the Radius, hath one and the same motion. 1719Quincy Phys. Dict. (1722) s.v., Altho the Ulna and Radius accompany one another, they touch but at their Extremities. 1758J. S. Le Dran's Observ. Surg. (1771) 12 The Radius of the left Arm was..broke. 1827Abernethy Surg. Wks. II. 72 The carpal bones were..driven upwards, some before, and others behind the ends of the radius and ulna. 1841R. E. Grant Comp. Anat. 65 In the perch..the two succeeding bones [are regarded] as the ulna and the radius. 1881Mivart Cat 94 At its lower end the radius becomes much broadened out. 1896Newton Dict. Birds 859 In Birds..there are..only two free carpals—one, generally termed the ‘radial’,..articulating with the distal end of both radius and ulna.
†d. (In full radius articulatus.) The alveolus of the belemnite. Obs. rare—1.
1753Chambers Cycl. Supp. s.v., Many of these radii are found remarkably compressed, bent, or distorted, which is an accident accounted peculiar to the fossils formed in animal moulds.
e. A dorsal fin. rare—1.
1822G. A. Mantell Geol. Sussex 229 Dorsal fin, or radius, of a fish allied to the Balistes... It consists of thirteen narrow parallel rays.
2. a. A rod, bar, etc., forming one of a set extending in several directions from one point; a wheel-spoke; a radiating part or filament, etc.
1726Bailey, Radius (in mechan.), a spoke, or felloe of a wheel, because they issue like rays from the centre of it. 1800J. Hurdis Fav. Village 169 His fine-spun radii flings from side to side. 1805Southey Madoc ii. x, Equal in number,..The spreading radii of the mystic wheel, Revolve. 1876Nature XIV. 465/1 A horizontal wheel of iron..having six radii. 1878Bell Gegenbaur's Comp. Anat. 41 In the animals built on a radiate plan the number of the ganglia is increased in correspondence with the radii.
†b. In fishes: (a) pl. The branchial lamellæ. (b) A fin-ray. Obs.
1691Ray Creation i. (1692) 66 These papillæ do well resemble the Aristæ or radii of a Fishes Gills. 1753Chambers Cycl. Supp. s.v. Radii, In the mackrel, the radii of the first fin of the back..are absolutely simple.
c. Bot. (a) The ray or outer whorl of ligulate florets surrounding the disk in a composite flower-head; the border of enlarged petals on a partial umbel; (b) a peduncle supporting a partial umbel; (c) a medullary ray.
1775J. Jenkinson tr. Linnæus Brit. Pl. Gloss., Radius, is the semifloscules that surround the disk. 1796Encycl. Brit. (ed. 3) III. 448/1 Radius, the rim or outward part, consisting of irregular florets. 1835Lindley Introd. Bot. (1839) 156 The peduncles which support the partial umbels are named radii. [1866Treas. Bot. 955/1 Radii Medullares, the medullary rays.] 1880Gray Struct. Bot. (ed. 6) 430/1 Ray (Radius), one of the radiating branches of an umbel.
d. Ent. One of the radiating subdivisions of a digitate wing.
1826Kirby & Sp. Entomol. IV. 338. 1848 Maunder Treas. Nat. Hist., Gloss.
e. One of the five arched rod-like pieces set radially in the mouth of a sea-urchin.
1877Huxley Anat. Inv. Anim. 576 The Latern consists of twenty principal pieces—five teeth, five alveoli, five rotulæ, and five radii.
f. Ornith. One of the processes on the barb of a feather, a barbule.
1893Newton Dict. Birds 240 The radii or barbules are attached in two opposite rows to the thick upper rim of the rami..Each radius is a thin lamella, about 1 mm. in length.
3. Math.
a. A straight line drawn to the circumference of a circle or the surface of a sphere from the centre, all lines so drawn being equal in length.
1656Hobbes Six Lessons Wks. 1845 VII. 256 Is the radius that describes the inner circles equal to the radius that describes the exterior? 1672Boyle Virtues of Gems 67 These rows of Planes reaching euery way, almost like so many radious's of a Sphere from the Centre. 1705Berkeley Commonpl. Bk. Wks. 1871 IV. 428 Circles on several radius's are not similar figures. a1721J. Keill Maupertuis' Diss. (1734) 47 Our first Method of finding the Curves, by Radii and Angles. 1831Brewster Optics iii. 23 Let a small tube..be so made that it may be attached to the board along any radius. 1853Herschel Pop. Lect. Sc. i. §53 (1873) 41 In a circle 22 miles in radius..every town and village was destroyed. 1879Calderwood Mind & Br. iii. 70 A series of fibres, some of which are arranged as radii, others in a circular manner.
transf. and fig.1649G. Daniel Trinarch., Hen. IV, xlv, Thus when All Causes are mett, their Radij must Spread. 1710T. Fuller Pharm. Extemp. 201 It [the Glyster]..driveth the Radii of the Miasmi outward. 1856Dove Logic Chr. Faith vi. §5. 369 Phenomena are the radii of Knowledge. 1860Farrar Orig. Lang. (1865) 15 The radii of inference from many other sources all converge to the common centre of a similar hypothesis.
b. A radial line of a curve, drawn from a certain point such as the focus to any point on the curve.
1836Lardner in Civil Eng. & Arch. Jrnl. I. 40/2 This..is altogether independent of the radius of the curve. Ibid., A curve of large radius. 1849Salmon Conic Sect. (1855) 162 In the hyperbola, the difference of the focal radii is constant. 1875B. Williamson Integr. Calc. 261 The area between two focal radii of a parabola and the curve.
c. Any line in an arrangement of straight lines diverging from a point, and resembling the radii of a circle.
1774Pennant Tour Scotl. in 1772, 358 On a live rock is cut the radii of a dial. 1802James Milit. Dict. s.v., In fortification, the radius is distinguished into exterior, interior, oblique, and right radius... The latter is a perpendicular line drawn from the center of a polygon to the exterior side.
d. In various phrases, as radius of concavity, radius of curvature, radius of dissipation, radius of an eccentric, radius of the evolute, radius of evolution, radius of explosion, radius of gyration, radius of inversion, radius of rupture, radius of torsion (cf. quots. and see the second element). radius of action: in Aeronautics, the distance that an aircraft can cover so as to leave sufficient fuel for its return to base.
1753Chambers Cycl. Supp. App., Radius of Concavity, in Geometry, is sometimes used for the Radius or ray of curvature. Ibid., s.v. Curvature, This circle is called the circle of curvature..and its semidiameter, the ray or radius of curvature. 1758J. Landen Resid. Anal. vii. 75 The right line CP is called the radius of evolution corresponding to the point P. 1834–47J. S. Macaulay Field Fortif. (1851) 201 In common mines the horizontal radius of rupture is equal to 13/4 times the line of least resistance... In a vertical direction, this radius is of the same length as the radius of explosion. 1879Thomson & Tait Nat. Phil. I. i. §281 The radius of gyration about any axis is therefore the distance from that axis at which, if the whole mass were placed, it would have the same moment of inertia as before. 1881Casey Sequel to Euclid iii. xx. 41 The point C is called the inverse of the point P,..and the constant R the radius of inversion. 1887D. A. Low Machine Draw. (1892) 47 The distance from the centre of the sheave to the centre of the shaft is called the radius or eccentricity of the eccentric. 1908Aeronaut. Jrnl. Apr. 44/2 In a 10 hours' run a distance of 300 kilm. (186 miles) might be traversed, the radius [of] action being 150 kilm. 1918Flying 20 Mar. 188/3 The problem of any extension of the radius of action is almost entirely one of increased efficiency..of modern aircraft.
e. radius vector, a variable line drawn to a curve from a fixed point as origin; in astronomy the origin is usually at the sun or a planet round which a satellite revolves. Also pl.
1753in Chambers Cycl. Supp. App. 1816Playfair Nat. Phil. II. 103 The line drawn from the moveable to the immoveable body, (the radius vector), describes areas round the latter proportional to the times. 1841C. Graves tr. Chasles' Properties of Cones 60 The sum or the difference of the two radii vectores. 1872Proctor Ess. Astron. xxx. 373 These cones will have a common axis—namely, the Earth's radius vector.
4. a. A circular area of which the extent is measured by the length of the radius of the circle which bounds it. Also pl.
1853Stocqueler Mil. Encycl. s.v. Grenade, It bursts into many pieces, scattering death and wounds among all who are within its radii. 1862M. E. Braddon Lady Audley xiii. 82, I shall first go to Audley Court, and look for George Talboys in a narrow radius. 1866Crump Banking ix. 180 Restricting its operations to a radius of sixty-five miles from London.
b. spec. in London, a circle of four miles in all directions from Charing Cross, outside of which cab-fares are higher.
1889Baedeker London (ed. 7) 28 Beyond the 4-mile radius from Charing Cross the fare is 1s. for every mile. 1899W. P. Ridge (title) Outside the Radius. Stories of a London Suburb.
5. Comb., as radius-bearing adj.; radius-bar, a bar pivoted at one end so that it can move in a circle or arc of a circle, used esp. in the parallel motion of a steam engine; radius-finder, an instrument for finding two radii (and thereby the centre) of a circle; radius rod = radius-bar; radius-saw, a circular saw in which the plate is journaled to the end of a radius-bar (Knight Dict. Mech. Suppl. 1884).
1839R. S. Robinson Naut. Steam Eng. 75 To these levers are also secured the radius bars, which are rods of wrought-iron, proceeding from the side rods. 1853Glynn Treat. Power Water 140 The radius bar carries a pen, the nib of which is in the line of the radius. 1858Murray Marine Engines (ed. 3) Gloss., Radius rods or bars,..are the guiding rods in a parallel motion. 1886Lockwood Dict. Terms s.v., Radius finder, a centre square. 1893Newton Dict. Birds 245 In Gallinæ there are from 10 to 12 somewhat stiff radius-bearing rami. 1907[see chain case s.v. chain n. 19]. 1946Happy Landings July 2/1 The inner radius rod of the starboard undercarriage was pulled away from the undercarriage. 1970K. Ball Fiat 600, 600D Autobk. 165/1 Radius rod, pivoted arm confining movement of a part to an arc of fixed radius.
▪ II. radius, v.|ˈreɪdɪəs|
[f. the n.]
trans. To round off, make (a corner or end) curved.
1938J. Healey Metal Aircraft ii. 14 Tubular rivets are a reamer fit, so having reamered the hole to size, radius the edge of the metal slightly. 1954Electronic Engin. XXVI. 538/1 All corners and bends should be ‘radiused’, i.e. finished with as large a radius as possible. 1962Engineering 6 July 10/1 The effect of radiusing the corners is also discussed. 1972Greer & Howell Mech. Engin. Craft Stud. II. iii. 157 (table) Millsaw. For sharpening circular saws, radiusing slots etc.
Hence ˈradiused ppl. a.
1954Archit. Rev. CXV. 144/1 Radiused blocks are made for use at corners. 1959New Scientist 31 Dec. 1339/2 Sharply radiused members are more expensive than straight members. 1975Mariner's Mirror LXI. 406 A slightly more radiused stem rabbet where it meets the keel. |