| 释义 |
refraction|rɪˈfrækʃən|
[ad. late L. refractiōn-em (Boethius), n. of action f. refringĕre: see refract v. and cf. F. réfraction (16th c.).]
†1.
a. The action of breaking open or breaking up. Obs. rare.
1578Banister Hist. Man vii. 91 This bloud by styrring..is made thinne, and together with the ayre mixed, which thus, by the same refraction, and beatyng together, is prepared. 1611Florio, Refrattione, a bursting or refraction. 1661Blount Glossogr. (ed. 2), Refraction, a breaking open.
b. Rebound, recoil. Obs. rare.
1653Harvey Anat. Exerc. ii. (1673) 135 The blood being forc'd against the hand, did by its reverberation and refraction, fly back four or five foot. 1661Blount Glossogr. (ed. 2), Refraction,..a rebound.
2. a. The fact or phenomenon of a ray of light, heat, († the sight), etc., being diverted or deflected from its previous course in passing obliquely out of one medium into another of different density, or in traversing a medium not of uniform density. More widely, change in direction of propagation of any wave as a result of its travelling at different speeds at different points along the wave front.
angle of refraction, the angle between the refracted ray and the perpendicular to the surface of the refracting medium at the point of incidence († or that between the refracted ray and a continuation of the incident ray). † axis of refraction, the perpendicular to the surface of the refracting medium at the point of incidence. double refraction, the fact of a ray of light being split up by certain minerals into two divergent, unequally refracted rays. index of refraction: (see index n. 9 a).
1603Holland Plutarch's Mor. 1295 The rainbow is..distinguished by sundry colours, by the refraction of our eie-sight against a cloud. 1646Sir T. Browne Pseud. Ep. 347 The colours are made by refraction of light, and the shadows that limit that light. 1677Grew Anat. Fruits iv. §6 By Refraction, Objects of all Sizes are represented on the Walls of the Eye. 1706W. Jones Syn. Palmar. Matheseos 301 The Refraction out of a Rarer Medium into a Denser is made towards the Perpendicular. 1797Encycl. Brit. (ed. 3) XIII. 279/2 The phenomena of refraction are explained by an attractive power in the medium through which light passes. 1831Brewster Optics xvii. 144 The refraction of the two pencils is called double refraction and the bodies which produce it are called doubly refractive bodies. c1860Faraday Forces Nat., Electric Light 177, I can employ the principle of refraction to bend and direct the rays of light. 1874Proc. R. Soc. XXII. 532 This refraction explains the well-known difference which exists in the distinctness of sounds by day and by night. 1880Le Conte Sight 32 All refraction is accompanied by dispersion. 1914[see absorption 4 (d)]. 1944A. Holmes Princ. Physical Geol. xiv. 297 (caption) Diagram to illustrate the development of a hooked spit by the refraction of oblique waves. 1971Nature 12 Feb. 452/2 T. D. Krishna Kartha describes his work on the variation of velocity (refraction) of microseisms approaching Cochin in southern India. 1974Harvey & Bohlman Stereo F.M. Radio Handbk. vii. 144 Refraction of the radio wave occurs due to the effects of the varying density of the gas layers in which the wave is travelling.
fig.1614Selden Titles Hon. Pref. C 4, I..euer..vsd that Medium only, which would not at all, or least, deceiue by Refraction. 1873Spencer Stud. Sociol. i. 12 To make allowance for the refraction due to the historic medium.
b. With a and pl. An instance of this.
1619J. Bainbridge Descr. Late Comet 10 A second refraction of the Sunne beames. 1660Boyle New Exp. Phys. Mech. xviii. 136 The various refractions that may happen in the Air. 1743Emerson Fluxions 284 The Sum of all the Refractions will be equal to the single Refraction [etc.]. 1796Kirwan Elem. Min. (ed. 2) I. 241 It causes a double refraction. 1867J. Hogg Microsc. i. i. 2 A table of the refractions which light experiences under different angles of incidence in passing from air into glass.
fig.1827Hare Guesses Ser. i. (1873) 2 When among the manifold refractions of Knowledge, Wisdom is almost lost sight of. 1860Emerson Cond. Life, Illusions, Even the prose of the streets is full of refractions.
†c. pl. Refracted beams. Also fig. Obs. rare.
1648Boyle Seraph. Love xxv. (1700) 152 Variety..such as we may see in the diversify'd refractions of the same sparkling Diamond. 1649G. Daniel Trinarch., Hen. IV, ccclxxxvii, Now..the Refractions of his Spirit Gild Only the Hemme of Life.
3. a. Astron. The deflection of the beams or light from heavenly bodies when not in the zenith, due to the refracting power of the atmosphere, which increases their apparent elevation.
Spec. called atmospheric refraction and astronomical refraction.
1603Sir C. Heydon Jud. Astrol. 137 There lieth a deceipt or fallacie in the refraction of beams, which cheifly happeneth about the Horizon, where the aire is alwaies thickest. 1669Sturmy Mariner's Mag. ii. 118 The Refraction of the Sun, Moon and Stars, causeth them to appear higher above the Horizon than they are. 1715tr. Gregory's Astron. (1726) I. 279 The uncertain Refractions will render the Operation doubtful; and besides, then the Sun ascends and descends too obliquely [etc.]. 1812Woodhouse Astron. x. 74 Refraction, by which a star, to appearance, is elevated above its true place. 1868Lockyer Guillemin's Heavens (ed. 3) 186 The Sun, actually already below the horizon, is raised up by refraction, and remains visible to us.
fig.1850Tennyson In Mem. xcii, Such refraction of events As often rises ere they rise.
b. The effect of the atmosphere in making terrestrial objects appear higher than they are.
Spec. called terrestrial refraction; see also quot. 1831.
1698J. Keill Exam. Th. Earth (1734) 173 He seems to allow too much, both for refraction and errors in the Observations. 1831Brewster Optics iii. xxxi. 255 Great local heats or local colds will produce great changes of refractive power, and give rise to optical phenomena of a very interesting kind. Such phenomena have received the name of unusual refraction. 1853Kane Grinnell Exp. x. (1856) 69 My sketches of the coast..show what strange diversities of outline may be induced by refraction.
4. The action of a medium in refracting light; refractive power or effect. Also fig.
1664Power Exp. Philos. i. 34 Which is helped and advantaged also by the refraction of the water wherein they swim. 1796H. Hunter tr. St.-Pierre's Stud. Nat. (1799) III. 27 Allowing one degree for the refraction of the Atmosphere in winter. 1849Kingsley Misc. (1860) II. 246 A deep pool..paved with sandstone slabs and boulders, distorted by the changing refractions of the eddies. 1870Lowell Among my Bks. Ser. i. (1873) 279 The willful refraction of a clear mind, twisting awry whatever enters it.
†5. A reduction on a charge or bill. Obs.
1727–41Chambers Cycl. s.v., I will deduct or make you a refraction of 30s. charged inadvertently in my bill. 1782Gentl. Mag. LII. 364 Mr. K. mentioned the refraction which the Company had on their side of their bargains with Government, as very advantageous.
6. The process of ascertaining the percentage of impurities contained in a sample of nitre; the sum of the impurities as thus ascertained.
1842Parnell Chem. Anal. (1845) 478 The total amount of these impurities in 100 parts of a sample of nitre is technically termed the ‘refraction’ of that sample. 1876Voyle & Stevenson Milit. Dict. 335/1 Government..generally purchases saltpetre at 5 per cent. refraction.
7. Ophthalm. Measurement of the focusing characteristics of eyes. Also attrib. Cf. refract v. 4.
1900J. Thorington Refraction & how to Refract ix. 229 The great danger in any refraction..is an overcorrection. 1928S. Duke-Elder Pract. Refraction xxi. 302 Test..the depth of cycloplegia by testing the accommodation before the refraction is done. 1953N. Bier Contact Lens Routine & Pract. iv. 56 The practitioner's contact lens refraction set. Ibid., An alteration of 0·5 mm in the corneal radius is approximately equivalent to 3·00 D.S. in refraction. 1961Lancet 30 Sept. 760/2 An ophthalmologist holds refraction clinics weekly in the surgery. 1975M. Ruben Contact Lens Pract. iv. 67/2 The cylinder found by refraction is -3·00 D.
8. attrib., as refraction error, refraction-index; also refraction-circle, one of two or more graduated circles attached to a refracting telescope in order to adjust its direction; refraction profiling Geol., profiling (sense 3) by means of refraction shooting; refraction shooting Geol., seismic prospecting in which shock waves generated at the earth's surface are detected at several points along a line some miles long, the relation between the time of arrival at each point and its distance giving information about the nature and depth of the underlying strata.
1875Knight Dict. Mech. 1909/2 The refraction-circle of the Washington Observatory. 1879St. George's Hosp. Rep. IX. 489 The pulsation was more marked in the eye with inferior sight. There was absolutely no refraction error. 1889Anthony's Photogr. Bull. II. 167 The relation between the refraction-index and the dispersion. 1929,1963Refraction profiling [see profiling vbl. n. 3]. 1929,1951Refraction shooting [see reflection shooting s.v. reflection 11]. 1960C. Gatlin Petroleum Engin. iii. 37/1 Refraction shooting is used primarily as a reconnaissance tool to select areas and obtain interpretative data for the more detailed reflection method. 1978Nature 27 Apr. 789/1 Seismic refraction shooting near the Isle of Lewis in the Outer Hebrides has shown the presence of major sedimentary units.
Hence reˈfractional a.; reˈfractionist, one skilled in the application of the laws of refraction, esp. for the correction of visual defects.
1871Hutton Ess. II. 84 He rejected ‘refractional’ theories of light with scorn. 1899Daily News 23 Feb. 5/1 An exhibition organized..in the interest of the refractionist. |