| 释义 |
extinction|ɛkˈstɪŋkʃən|
Also 5 extinccion.
[ad. L. ex(s)tinctiōn-em, n. of action f. ex(s)tinguĕre: see extinguish. Cf. F. extinction.]
The action of extinguishing; the fact or state of being extinguished.
1. a. The quenching, putting out (of fire, light, anything burning or shining; fig. hopes, passions, life, etc.); the fact of being quenched; the process of becoming, or the condition of being, extinct.
In Optics occas. used for the stoppage of light by absorption, interference, etc.
1494Fabyan Chron. vii. 589 He ordeyned at Westminster to brenne perpetuelly w'out extinccion .iiii. tapers of waxe. 1646Sir T. Browne Pseud. Ep. ii. iii. 68 Red hot needles or wires extinguished in quicksilver, do yet acquire a verticity according to the Laws of position in extinction. 1669Boyle Contn. New Exp. i. Notes (1682) 191 Several Ignitions and Extinctions. 1672G. Harvey Morb. Angl. v. 14 The parts are consumed through extinction of their native heat. 1838Prescott Ferd. & Is. (1846) I. iii. 186 The sudden extinction of those hopes which she had so long..cherished. 1843Penny Cycl. XXVI. 424/1 The birth..and extinction of volcanoes are phenomena seen in separate parts of the earth's surface. 1860Tyndall Glac. i. xxvii. 204 The alternate appearance and extinction of the light. 1866Carlyle Remin. (1881) II. 275 A bright lamp flickering out into extinction.
b. The slaking (of lime); † ‘the quenching of red-hot minerals in some liquor, to abate their sharpness, or to impart their virtue to the liquor’ (Phillips 1706); † concr. a tincture made by this process. extinction of mercury: (see quot. 1842).
1646Sir T. Browne Pseud. Ep. ii. v. §3. 85 Gold inwardly taken..either in substance, infusion, decoction or extinction. Ibid. ii. v. §3. 86 [Alloyed gold] is actually dequantitated by fire, and possibly by frequent extinction. Ibid. iii. xxii. 165 For speedier operation we make extinctions, infusions, and the like. 1842Dunglison Med. Lex. (ed. 3), Extinction of mercury, trituration of mercury with lard or other substance, until the mercury disappears. 1848Craig, Extinction of lime.
c. Physics. Reduction in the intensity of radiation. (i) Reduction in the intensity of a beam of light as a result of absorption and scattering as it passes through a medium.
1794G. Adams Nat. & Exp. Philos. II. xxi. 406 Reflexion, refraction, and extinction, are affections of light by transparent bodies. 1827–8J. F. W. Herschel in Encycl. Metrop. (1845) IV. 431 The extinction of a beam of homogeneous light in passing through a homogeneous medium. 1957H. C. van de Hulst Light Scattering by Small Particles xviii. 388 Extinction can be measured by observing the intensity..of a light source as seen through a container with scattering particles. 1963J. M. Stone Radiation & Optics xiv. 335 Extinction is accounted for partly as scattering and partly as absorption. Extinction may..consist entirely of absorption (for example, in an opaque screen of negligible reflectance) or almost entirely of scattering (for example, from..a very thick cloud in the sky).
(ii) The state or condition of darkness in a crystal placed in polarized light between crossed nicols. Hence angle of extinction, the angle formed, on rotation, between the position of extinction of a ray of light and a principal crystallographic direction. Also attrib.
1873J. Tyndall Six Lectures on Light iv. 133 This brings us at once to the part played by the analyzer, the sole function of which is to recompound the two vibrations emergent from the gypsum. It reduces them to a single plane, where, if one of them be retarded by the proper amount, extinction will occur. 1912R. W. Clark tr. Weinschenk's Petrogr. Meth. 67 Maximum brightness is obtained when the vibration directions of the crystal are at 45° to those of the nicols. It diminishes upon further rotation and passes gradually over into complete darkness when these directions are respectively parallel. This latter position is also called the position of extinction, and the vibration directions in the crystal, the extinction directions. Ibid. 70 Extinction Curve for Diopside. Ibid., In triclinic minerals the determination of the extinction angles is of value only when the orientation of the face upon which they are observed is accurately known. 1921A. Holmes Petrogr. Meth. 126 When a transparent mineral fragment is rotated between crossed nicols various phenomena may be observed... If the object remains dark, and is therefore isotropic, the total extinction indicates an amorphous or cubic (isometric) mineral in an unstrained condition, or a basal section of a uniaxial mineral (tetragonal, hexagonal, or trigonal). 1937Discovery Sept. 283/2 A complete record of the colour variation and the angles of extinction can be permanently obtained.
(iii) A reduction in the intensity of X-rays diffracted by a crystal owing to interference between the incident beam and beams multiply diffracted by the lattice planes (primary extinction) and to the progressive weakening of the incident beam in its passage through the crystal as energy is diverted into the diffracted beams (secondary extinction).
1914C. G. Darwin in Phil. Mag. 6th Ser. XXVII. 681 The extinction is complete long before the [X-]rays going in a slightly different direction are appreciably absorbed. This fact is important in explaining the reflexion from an ordinary imperfect crystal. 1922― in Ibid. XLIII. 804 The extinction itself..exerts two effects, which may be called primary and secondary. 1934W. P. Davey Study Crystal Struct. x. 308 The cleavage faces of all actual single crystals are perfect enough to show a little primary extinction and are imperfect enough to show a great deal of secondary extinction. 1948K. Lonsdale Crystals & X-Rays vi. 140 The effect of this primary extinction..is an enormous apparent increase in absorption, over a very restricted range of angle. 1966D. G. Brandon Mod. Techniques Metallogr. 83 Crystal imperfections will prevent double diffraction and hence prevent extinction, leading to an increased diffracted intensity in regions of lattice strain.
2. Suppression, abolition (of an institution, etc.); the complete wiping out (of a debt).
1651Hobbes Leviath. ii. xxix. 168 The Extinction of their Democracy. 1748Anson Voy. ii. xiv. 282 The extinction of their religion, and the slaughter of their ancestors. 1751Johnson Rambler No. 145 ⁋1 The public would suffer..inconvenience..from the extinction of any common trade. 1839Thirlwall Greece VIII. 469 After the extinction of the national independence. 1845McCulloch Taxation (1852) 462 The plan for the gradual extinction of the national debt.
3. a. The action of blotting (a living being, a soul) out of existence; destruction, annihilation.
1615Crooke Body of Man 333 We therefore define an abortment to be Either the issuing of an imperfect Infant or his extinction and death in the wombe. 1646Bp. Hall Balm Gil. 188 The utter extinction of those we loved. 1676Glanvill Ess. v. 19 Doctrines, such as..utter extinction, and annihilation of the Wicked after the Day of Judgment. 1796Morse Amer. Geog. I. 135 Which destruction they call the second death, and describe it as a perfect extinction. 1878Browning La Saisiaz 32, I..declare the soul's eclipse Not the soul's extinction.
†b. Effacement, utter disgrace or ruin (of a person). Obs.
1542Udall in Lett. Lit. Men (Camden) 5 To recover a man from present extinction.
4. Of a race, family, species, etc.: The fact or process of becoming extinct; a coming to an end or dying out; the condition of being extinct.
1602W. Fulbecke 2nd Pt. Parall. 63 If a man deuise to his daughter his lands..vntill she marie..it onely signifieth an extinction of the legacie when the mariage is accomplished. 1659C. Noble Mod. Answ. to Immod. Q. 15 By..extinction of the male blood it received an alteration. a1729J. Rogers 19 Serm. (1735) 135 The Extinction of Nations, and the Desolation of Kingdoms. 1818Cruise Digest (ed. 2) VI. 569 Any number of lives, the extinction of which could be proved without difficulty. 1875Bryce Holy Rom. Emp. xix. (ed. 5) 354 The extinction of the male line of Hapsburg in the person of Charles the Sixth. 1880A. R. Wallace Isl. Life 61 The most effective agent in the extinction of species is the pressure of other species.
5. attrib., as extinction coefficient, any coefficient that gives a measure of the total degree of extinction of radiation by a medium; extinction frequency (see quot.); extinction meter, a photographic exposure meter which gives readings in terms of visual comparisons.
1902Encycl. Brit. XXX. 237/1 After traversing thickness x the intensity I is reduced to I′ = Ie—ax where e is the number 2·71828..and a is known as the extinction-coefficient. 1912P. G. Nutting Outl. Appl. Optics 12 In theoretical work the most useful specification of absorption is the absorption per wave length called the extinction coefficient or absorptive index. 1959H. Barnes Oceanogr. & Marine Biol. 162 The clarity of the water, that is, its ability to transmit light (as measured by the so-called extinction coefficient), depends upon the wavelength of the light.
1953Amos & Birkinshaw Television Engin. I. 277 The frequency..at which zero output occurs is known as the first critical or extinction frequency.
1931J. H. Reyner Cine-Photogr. for Amateurs v. 58 These meters are often known as extinction meters, because the light coming through them is gradually reduced to or worked up from an extinction point. 1951G. H. Sewell Amateur Film-Making (ed. 2) ii. 19 An early type [of exposure meter] used for cinematography was the extinction meter, in which the subject was observed through a small telescope in which was a density wedge that was used in assessing the correct exposure for the subject. |