| 释义 |
induced, ppl. a.|ɪnˈdjuːst|
[f. induce v. + -ed1.]
1. a. Brought on, caused, or produced, by attraction, persuasion, etc. (see esp. induce v. 4 b); induced current, an electric current excited by induction (sense 10). Also, affected by induction as induced magnet. More widely (in sense 4 of the vb.), caused or brought into being artificially or by some extraneous agent or process; not spontaneous (cf. induction 9).
1611Cotgr., Meu,..also induced, inclined, persuaded. 1652Needham tr. Selden's Mare Cl. 21 Som deriving the Dominion of the Republick over the Sea from Custom, som from prescription, others from an induced subjection. 1812Sir H. Davy Chem. Philos. 133 The conductor, which is thus affected by induced electricity. 1830Herschel Stud. Nat. Phil. 324 The phenomena of the communication of magnetism and what is called its induced state, alone remain unaccounted for. 1852Grove Contrib. Sc. in Corr. Phys. Forces (1874) 359 The ordinary plan for producing an induced current. 1874Carpenter Ment. Phys. i. ix. §2 (1879) 393 The essential feature..of natural and induced Reverie. 1922C. C. Van Blarcom Obstetr. Nursing xiii. 309 Induced abortion applies to the termination of pregnancy before the child is viable,..and is performed solely in the interests of the mother, as the fetus is always lost. 1929Biol. Abstr. III. 1495/2 The distal skeleton of the induced limbs might be normal. 1941Jrnl. Nat. Cancer Inst. II. 198/2 The incidence of spontaneous hepatomas..is decidely below that of the induced tumors in our experimental animals. 1947Growth XI. 225 (heading) The occurrence of substrate-induced enzyme formation. 1960B. I. Balinsky Introd. Embryol. vi. 168 In other experiments the whole of the induced neural tube was developed exclusively from host tissue. 1962H. D. Bush Atomic & Nucl. Physics v. 105 (heading) Induced nuclear transmutations. 1970G. K. Woodgate Elem. Atomic Struct. iii. 32 Three radiation processes are postulated: spontaneous emission,..absorption,..and induced emission.
b. induced (radio)activity, radioactivity brought about in otherwise non-radioactive material by its transformation under bombardment or irradiation or by the proximity of radioactive material.
[1899P. & M. Curie in Compt. Rend. CXXIX. 714 Nous avons constaté que les rayons émis par ces matières, en agissant sur des substances inactives, peuvent leur communiquer la radioactivité, et que cette radioactivité induite persiste pendant un temps assez long.] 1900Rutherford in Phil. Mag. XLIX. 169 Two or three layers of ordinary foolscap-paper completely cut off the ordinary radiation given out by thorium compounds, but do not much diminish the amount of induced radio⁓activity. 1904F. Soddy Radio-Activity ii. 33 With the power of a radio-active element to produce a radio-active emanation is bound up its power to impart radio-activity to objects in the neighbourhood. Rutherford discovered this property for the thorium emanation, and designated it the excited activity. M. and Mme. Curie..called it the induced activity. 1913[see excited ppl. a. 2 d]. 1926R. W. Lawson tr. Hevesy & Paneth's Man. Radioactivity viii. 90 Before the material nature of the active deposit had been recognised, it was customary to call the activity acquired by bodies that had been in contact with emanation by the name of ‘induced activity’. 1963B. Fozard Instrumentation Nucl. Reactors i. 7 When the irradiated material is removed from the neutron flux the induced activity is measured. 1966McGraw-Hill Encycl. Sci. & Technol. XI. 277/2 The yield of any induced radioactivity is the initial rate of production of the activity under the particular conditions of nuclear bombardment.
2. Biol. Of a bacterium: that has been induced (see induce v. 4 e).
1951Jrnl. Bacteriol. LXII. 305 The induced bacteria double in length and thickness..between irradiation and lysis. 1963G. S. Stent Molecular Biol. Bacterial Viruses xii. 312 There is little doubt..that the phages are liberated by lysis of the induced lysogenic cells. 1970Jrnl. Virol. V. 244/2 After mitomycin C treatment, DNA continues to be synthesized by the induced bacterium.
3. Special comb.: induced drag, that part of the drag on an aircraft or aerofoil which arises from the development of lift; induced draught, a draught towards a fan or other device that draws air through a furnace, up a chimney, etc.; induced reaction, a chemical reaction that is accelerated by the presence of an inductor (see inductor 4) that reacts with one of the reactants.
1926H. Glauert Elem. Aerofoil & Airscrew Theory x. 132 The lift force is..inclined backwards at the small angle..and therefore gives a component in the direction of the drag force. This component is called the *induced drag, since it is caused by the induced velocity of the trailing vortices. 1931,1948[see drag n. 7 e]. 1962F. I. Ordway et al. Basic Astronautics viii. 340 There are three basic types of aerodynamics drag: skin-friction drag, form drag, and induced drag.
1887W. A. Martin in Trans. Soc. Engin. 1886 117 In comparing the three systems, of ordinary draught, forced draught, and the author's *induced draught,..it is necessary to say [etc.]. 1894Westm. Gaz. 29 Dec. 3/2 The other improvement is that of induced—instead of forced—draught. 1971Sci. Amer. May 73/3 In a forced-draft [cooling] tower the fan is at the bottom and pushes the air up through the tower; in an induced-draft tower the fan is at the top and pulls the air up.
1903Jrnl. Chem. Soc. LXXXIV. ii. 277 The reaction between bromic and sulphurous acids is the primary spontaneous reaction; and that between bromic and arsenious acids is the secondary *induced reaction. 1917Ibid. CXI. i. 702 In all the experiments on induced reactions recorded above, the oxidising agents take part and are themselves reduced during the chemical change. 1964J. R. Partington Hist. Chem. IV. vi. 194 Closely related to the subject of autoxidation is that of induced reactions. |