| 释义 |
characteristic, a. and n.|ˌkærəktəˈrɪstɪk|
Also 7 -ick, -ique.
[ad. Gr. χαρακτηριστικός in same sense; cf. F. caractéristique.]
A. adj.
1. a. That serves to indicate the essential quality or nature of persons or things; displaying character; distinctive; typical. Const. of.
1665J. Spencer Prophecies 65 The Characteristick note between false and true Prophets. 1762Gibbon Misc. Wks. 1814 V. 249 The characteristic letter, and the termination of verbs. 1793Holcroft Lavater's Physiogn. xxi. 110 Fleshy lips, broad chin, and large ears, I believe to be characteristic of the Dutchman. 1880Haughton Phys. Geog. iii. 83 Shells characteristic of the Triassic and Jurassic periods.
b. Math.
1727–51Chambers Cycl., Characteristic Triangle of a Curve, in the higher geometry, is a rectilinear right-angled triangle, whose hypothenuse makes a part of the curve, not sensibly different from a right line. 1879Thomson & Tait Nat. Phil. I. i. §331 The function thus determined and employed to express the solution of the kinetic problem was called the Characteristic Function.
c. characteristic curve: a graph showing the relationship between two variable but interdependent quantities; spec. (see quot. 1955).
1902Encycl. Brit. XXVIII. 90/1 Curves delineating the relation of these variables for any incandescent lamp are called its characteristic-curves. 1922Glazebrook Dict. Appl. Physics II. 147/2 Characteristic Curves, curves showing the relation between current and voltage for any electrical apparatus. 1923[see bromide 4]. 1955Gloss. Terms Radiology (B.S.I.) 55 Characteristic curve, a curve showing the relation between the common logarithm of exposure..and the photographic density under specified conditions of processing. 1957R. W. G. Hunt Reprod. Colour iv. 71 The characteristic curve (density plotted against log exposure) of a typical reversal colour photographic process is shown.
d. characteristic impedance, ‘the impedance of a uniform alternating-current transmission line of indefinite length (as a long telephone cable) measured at the input end where the voltage is applied’ (Webster 1961).
1923Bell System Techn. Jrnl. II. ii. 1 The transmission of alternating currents over any transmission line..depends only on the propagation constant and the characteristic impedance. 1929E. Mallett Telegr. & Teleph. viii. 178 Instead of a characteristic resistance..there will be a complex characteristic impedance. 1940Chambers's Techn. Dict. 153/1 Characteristic impedance of an antenna (Radio), the impedance with which certain forms of antennae..must be terminated to prevent the formation of standing waves. Characteristic impedance of a line (or filter) (Elec. Comm.), the apparent impedance of an infinitely long line at any point, or of an infinite number of filter sections.
e. Nuclear Physics. Designating radiation the wavelengths of which are peculiar to the element which emits them.
1908Barkla & Sadler in Phil. Mag. XVI. 571 A characteristic homogeneous radiation was emitted by a metal when the primary beam to which the metal was exposed was of more penetrating type than the characteristic radiation. 1912W. H. Bragg Stud. Radioactivity xiv. 156 It is only when the β corpuscle possesses energy in excess of the same value that it is able to excite the characteristic X radiation of the atom. Ibid. xv. 175 Let K2 be the absorption coefficient of the same plate for its own characteristic rays. 1938R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity (ed. 2) v. 63 The characteristic rays of an element are related in a simple manner to the atomic number. Ibid. 65 The hardest characteristic radiation known, viz. the K-radiation of uranium. Ibid. viii. 87 The characteristic X-ray spectrum.
2. Relating to or descriptive of character.
1725H. Gally (title) Theophrastus, Moral Characters, with notes and a critical essay on Characteristic Writings.
B. n.
1. A distinctive mark, trait, or feature; a distinguishing or essential peculiarity or quality.
1664H. More Myst. Iniq. i. 2 The most obvious circumstantial Characteristick of the Whore of Babylon. 1677R. Cary Chronol. i. ii. i. iv. 59 These numbers..are undoubted Characteristiques..serving to discriminate one Year from another. 1762–71H. Walpole Vertue's Anecd. Paint. (1786) 265 The chapel of Lincoln's-inn has none of the characteristics of that architecture. 1772Junius Lett. lxviii. 335 Superstition is certainly not the characteristic of this age. 1858Doran Crt. Fools 125 It was the characteristic of our English kings, to be liberal to their buffoons. 1879Lubbock Sci. Lect. i. 9 Color, scent, and honey are the three characteristics by which insects are attracted to flowers.
†b. ? A distinctive name or appellation. Obs.
1851Life of Ken (1854) 653 (D.), I never use any characteristic in the prayers myself, nor am present when any is read.
†2. A system of alphabetic characters; = character n. 4 b. Obs.
1769tr. Michaelis' Opin. Lang. (1771) Introd. 6 A characteristic of easier execution. Ibid. 77 The written language of the Chinese..is rather a characteristic than a language.
3. Math. The whole number in a logarithm. characteristic of a cubic: the invariable anharmonic ratio of the four tangents which can be drawn to a plane cubic from any one of its own points.
1727–51in Chambers Cycl. 1801Hutton Course Math. (1806) I. 156 The integral part of a logarithm, usually called the Index, or Characteristic.
4. = characteristic curve.
1902Encycl. Brit. XXVII. 587/2 A curve connecting together corresponding values of external current and terminal voltage for a given speed of rotation is known as the external-characteristic of the machine... The ‘external characteristic’ for a shunt machine has an entirely different shape. 1918V. H. Laughter Operator's Wireless & Telephone Handbk. xi. 177 Characteristic, Dynamic, of a Conductor..the relation given by the curve obtained when the impresssed E.M.F.'s are plotted as ordinates against the resultant currents as abscissas, both E.M.F.'s and currents varying at the given frequency and between the given extremes. 1930Engineering 6 June 748/2 The boiler feed pumps were all rotary pumps and had a very flat characteristic. 1958Amos & Birkinshaw Television Engin. II. i. 31 One possible form for the phase-frequency characteristic of a practical amplifier. |