| 释义 |
dispersion|dɪˈspɜːʃən|
Also 5 -cioune, 6 -tion.
[a. F. dispersion (disparcion 13th c. in Hatz.-Darm.), or ad. L. dispersiōn-em scattering, n. of action f. dispergĕre: see disperse v.]
1. The action of dispersing or scattering abroad; the condition or state of being dispersed; scattering, distribution, circulation.
Early applied to the scattering of the Jews among the Gentiles after the Babylonian Captivity; whence sense 5.
c1450Mirour Saluacioun 3635 The Jewes yt tyme hadde bene thorgh the werlde in dispersionne. 1555Eden Decades 266 In the fyrst dispertion of nations. 1656Manasseh ben Israel Vind. Judæorum in Phenix (1708) II. 423, I conceiv'd that our universal Dispersion was a necessary Circumstance to be fulfil'd. 1786Burke W. Hastings Wks. 1842 II. 180 The dispersion and exile of the reigning family. 1793Trial Fyshe Palmer 22 The alleged dispersion of a seditious writing. 1882Vines Sachs' Bot. 929 The specialities of organisation which effect the dispersion of their seeds.
fig.c1450tr. De Imitatione i. xx, What comeþ þerof but grucching of conscience & dispersion of herte?
2. The action of diffusing or spreading; diffusion.
1664Power Exp. Philos. i. 29 That all Vegetables have a constant perspiration, the continual dispersion of their odour makes out. 1794Sullivan View Nat. II. 36 When the natural dispersion of heat is disturbed..then a sensible heat is produced. 1874Hartwig Aerial W. ii. 21 By this means is also gradually effected the dispersion of all gases.
3. Med. ‘The removal of inflammation, suppuration, or other morbid processes, from a part, and restoration to health’ (Syd. Soc. Lex.); dissipation.
1753Chambers Cycl. Supp. s.v., This is commonly term'd in surgery the resolution or dispersion of tumors. Ibid., Remedies for the dispersion of inflammations. 1789W. Buchan Dom. Med. (1790) 573 An inflammation..must terminate either by dispersion, suppuration, or gangrene.
4. Optics. The divergence or spreading of the different-coloured rays of a beam of composite light when refracted by a prism or lens, or when diffracted, so as to produce a spectrum: esp. in reference to the amount of this divergence.
1727–51Chambers Cycl., Point of Dispersion, is a point from which refracted rays begin to diverge. 1794G. Adams Nat. & Exp. Philos. II. xxii. 447 This diffusion or dispersion of the rays is greater. 1833N. Arnott Physics (ed. 5) II. 199 The quality of..bending a beam, or of refraction, and that of dividing it into coloured beams, or of dispersion, are distinct. 1871tr. Schellen's Spectr. Anal. §18. 63 The decomposition of white light into its colored rays is called dispersion. 1881N. Lockyer in Nature No. 617. 399 [The lines] are..visible when considerable dispersion is employed.
5. the Dispersion: The Jews dispersed among the Gentiles after the Babylonian Captivity; the scattered communities of Jews in general, or the communities in some single country, as the Egyptian Dispersion; = diaspora.
1382Wyclif 1 Pet. i. 1 To the chosen gestis of dispersioun [gloss, or scateringe abroad]. c1450St. Cuthbert (Surtees) 3781 Of ysrael þe dispercioune he gadird samen fra strete and toune. 1582N. T. (Rhem.) John vii. 35 Wil he goe into the dispersion of the Gentiles, and teach the Gentiles? 1641Evelyn Mem. (1857) I. 30 Transported..to all the desolate ports and havens throughout the world, wherever the dispersion was, to convey their brethren and tribes to the Holy City. 1880J. E. Carpenter tr. Ewald's Hist. Israel V. 4 The ‘Coasts of the Sea’..are now (as in the eighth century) mentioned as a residence of the Dispersion. 1893Smith & Fuller Dict. Bible s.v., The African Dispersion..preserved their veneration for the ‘holy city’.
6. law of dispersion: The ‘Law of Error’ as regards distance from the mark without reference to the direction of error. So dispersion = the degree of scatter of values in a set of observations.
1876Catal. Sci. App. S. Kens. Mus. §48 Testing how far the relative numbers in the several classes accord with the results of the Law of Error or Dispersion. Ibid. §49 The well-known bell-shaped curve, by which the law of error or of dispersion is mathematically expressed. 1897Jrnl. R. Statist. Soc. LX. 865 Notice that no term measuring the dispersion of weights enters in the formula; but that the approximation was made on the assumption that the weights were equal. 1930Engineering 13 June 756/1 The observations were characterised by a large dispersion, which was attributed to the numerous factors involved. 1963B. Fozard Instrum. Nucl. Reactors vii. 70 A commonly used measure of the dispersion or scatter of a number of observed values about the central values is the standard deviation σ.
7. Physical Chem. A type of intimate mixture in which one substance is present in a large number of separate small regions distributed throughout another, continuous, substance; examples are emulsions (one liquid in another) and aerosols (a solid or a liquid in a gas); also, the state of being so distributed. Also attrib., as dispersion medium; a substance that may contain another substance ‘dispersed’ in it.
1915[see dispersed ppl. a. c]. 1919E. Hendrick Chem. Everyday Life 74 Soap is a colloid, and when we get a little of it in a great deal of water we have it in dispersion. 1924A. Findlay Physical Chem. 173 A colloidal sol..consists of finely divided particles (the dispersed phase) distributed throughout a dispersion medium. 1927Crocker & Matthews Theoret. & Exper. Physical Chem. 274 Dispersion medium, the continuous phase in a colloidal solution, corresponding to the solvent in true solution. 1944Petroleum Refiner Dec. 504/2 The property of maintaining insoluble matter (sludges and contaminants) in dispersion in the oil so that they will not settle out. 1957Encycl. Brit. VI. 25/2 A foam is a gaseous dispersion (usually of air) in a liquid continuum. Ibid., Pastes are concentrated dispersions of fine solid particles in a liquid continuum. 1958Times Rev. Industry May 69/1 The main dispersion mill..will turn out 500 gallons of emulsion paint in an hour.
8. attrib. dispersion hardening Metall., a process of ageing produced by heating at high temperatures.
1891Times 28 Sept. 13/6 By an appropriate choice of dispersion lenses. 1932Metallurgist VIII. 110/1 The hardening depends on the degree of dispersion of the particles, and it is accordingly sometimes known as dispersion hardening. 1934H. O'Neill Hardness of Metals vi. 195 ‘Dispersion hardening’ and ‘precipitation hardening’ are good labels to employ for the phenomenon in general. |