| 释义 |
induction|ɪnˈdʌkʃən|
Also 5–6 induccyon, (6 enduction).
[a. F. induction (14th c.) or ad. L. inductiōn-em, n. of action from indūcĕre to induce.]
†1. The action of inducing by persuasion; inducement. Obs.
1490Caxton Eneydos xii. 44 The incitacyons moeued by naturell dylection, whiche commen of thy self, with out ony othre induction. Ibid. xxix. 113 There was som deceptyon or frawdulent induction that hath made her to condescende therunto. 1588Allen Admon. 5 Not the pope alone but God himselfe suerly, & other the most zelous & mightiest princes in Christendom by his Induction.
2. The action of introducing to, or initiating in, the knowledge of something; the process of being initiated; introduction, initiation.
1526Pilgr. Perf. (1531) 25 b, Of these iii examples we may take a general induccyon or informacyon to our sayd iourney. 1531Elyot Gov. i. xxii, The principal cause of this my little enterprise is to declare an Induction or mean how children..may be trayned into the waye of vertue. 1600Holland Livy 379 A strange kind of induction and institution of the souldiours, binding them to take their oth,..as if they were to take orders in some holy mysteries. 1724De Foe Mem. Cavalier (1840) 59, I have never yet seen any service, and must have my induction some time or other. 1877Black Green Past. xli, Society is vastly more concerned in the induction of its youthful members into these branches of culture than it is in teaching them to bawl harmoniously.
attrib.1962B.B.C. Handbk. 162 Induction courses were also continued during the year for all senior members of staff joining the Corporation to acquaint them with its purpose, organization, and basic procedures. 1962E. Godfrey Retail Selling & Organization xi. 121 It may be very useful to provide a special week or fortnight of induction training for them [sc. juniors]. 1965New Statesman 30 Apr. 678/3 The organisation of refresher or induction courses. 1966Ibid. 14 Jan. 49/1 Many firms run so-called ‘induction’ classes for new entrants, teaching them something about the company and its welfare provisions, perhaps giving them a brief run-down on the reasons for deductions from their wage packets, and even occasionally dealing with safety and hygiene.
3. a. That which introduces or leads on or in to something; an introduction. Now rare.
c1540Four P.P. in Hazl. Dodsley I. 355 Comparing that life for the best Induction to your endless rest. 1556J. Heywood Spider & F. liv. 12 Enter the path..One depe enduction wherto..Is to flee rash deedes rashlie done. 1631Chapman Cæsar & Pompey Plays 1873 III. 149 This prepares a good induction to the change of fortune. 1646Buck Rich. III 118 (T.) An induction to those succeeding evils which pursued that inconsiderate marriage. 1894Blackmore Perlycross 15 An old-fashioned Inn... This..was not in the Parson's opinion a pleasing induction to the lych-gate.
b. An introductory statement; a preface, preamble, or introduction (to a book or the like). arch.
1533More Answ. Poysoned Bk. Wks. 1094/1 In the .xi. leafe he hath an other argument, towarde whyche he maketh a blynde induccion before. 1559T. Sackville The Induction to Mirrour for Magistrates. 1607Beaum. & Fl. Woman-Hater Prol., Inductions are out of date, and a prologue in verse is as stale as a black velvet cloak. 1645Milton Colast. Wks. (1851) 362 That which hee takes for the second Argument..is no argument, but an induction to those that follow. 1875A. W. Ward Eng. Dram. Lit. I. Introd. 11 In the form of a Prologue or..by means of a separate Induction, or even by an inductive Dumb-show.
†c. The initial step in any undertaking. Obs.
1574Shakes. Rich. III, i. i. 32 Plots haue I laide, Inductions dangerous,..To set my Brother Clarence and the King In deadly hate, the one against the other. 1596― 1 Hen. IV, iii. i. 2 These promises are faire, the parties sure, And our induction full of prosperous hope.
†d. A leading on or gradual transition from one thing to another. Obs.
1638F. Junius Paint. of Ancients 281 [In a centaur] the horse..turneth from the one into the other as by a quiet and insensible induction.
†e. Music. (See quot.) Obs.
1597Morley Introd. Mus. 92 Here they set downe certaine obseruations, which they termed Inductions..euerie proportion whole, is called the Induction to that which it maketh being broken. As tripla being broken in the more prolation will make Nonupla, and so is tripla the Induction to nonupla.
4. a. Eccl. The action of formally introducing a clergyman into possession of the church to which he has been presented and instituted, together with all rights, profits, etc. pertaining to it.
c1380Wyclif Wks. (1880) 248 For institucion and induccion he schal ȝeue moche of þis god þat is pore mennus to bischopis officers, archdekenes & officialis. 1583Stubbes Anat. Abus. ii. (1882) 81 At the time of their initiation, institution, induction and admission. 1660R. Coke Power & Subj. 21 The division of all parishes..the right of institution and induction..were all originally of the King's foundation and donation. 1765Blackstone Comm. I. xi. 307 The method of becoming a parson or vicar is much the same. To both there are four requisites necessary: holy orders; presentation; institution; and induction. 1875Gladstone Glean. VI. lii. 228 He had indeed received a formal induction..from the arch priest of Cavriana.
b. In Presbyterian churches: The placing of a minister already ordained in a new pastoral charge. (Distinguished from ordination.)
1871Sir H. Moncrieff Pract. F.C. of Scot. (1877) 269 The Presbytery resolved to loose him from his present charge and translate him to—,..and they request that Reverend Court to give them notice of his Induction when it takes place. Ibid. 270 Edict previous to Ordination or Induction.
c. gen. The formal introduction to an office, position, or possession; installation. (Cf. endue v. 1.)
1460J. Capgrave Chron. (Rolls) 301 Ve send oure special legates to trete..of the restitucion, and the real induccioune of the duchy of Gian. 1828Webster s.v., Induction is applied to the introduction of officers only when certain oaths are to be administered or other formalitites are to be observed, which are intended to confer authority or give dignity to the office. In the United States it is applied to the formal introduction of civil officers, and the higher officers of colleges.
d. U.S. Introduction into military service (cf. induct v. 3 b). Also attrib.
1934in Webster. 1940Congress. Rec. 6 Sept. 11676/1 Any person..shall be afforded an opportunity to volunteer for induction. 1951N.Y. Herald-Tribune 26 Dec. 11/3 You label this procedure of impressing R.O.K. Army members into your army as voluntary induction... It is nothing more than forced induction, impressment. 1967Boston Sunday Herald 26 Mar. ii. 7/7 Clay has been ordered to appear for induction in the Army on April 11. 1973C. Himes Black on Black 209 Here is your induction papers... I hope the army likes you bettern I does. 1973Times Lit. Suppl. 19 Oct. 1269/1 One summer the dreaded Induction Notice comes and he goes to war.
5. The action of introducing or bringing in (a person, custom, etc.). rare.
1604Dekker King's Entert. Wks. 1873 I. 271 The induction of such a person, might pass very currant. 1610Healey St. Aug. Citie of God ii. xiii. (1620) 66 Such things as our Gods themselues doe make sacred, by their owne expresse induction of those plaies into our customes. 1612Woodall Pref. Surg. Mate Wks. (1653) 9 The Knowledge and use of all such medicines..as were of his production and induction. 1802Lamb J. Woodvil iv. ii, Therefore, without much induction of superfluous words, I attach you..of high treason.
6. The bringing forward, adducing, or enumerating of a number of separate facts, particulars, etc., esp. for the purpose of proving a general statement.
1551Gardiner Explic., Transubst. 125 (R.) For the auctour of this booke concludeth solemly thus by induction of the premisses, that euen so the bodye of Christe was after thascension chaunged into the godly substaunce. 1624Bedell Lett. iii. 57 The rest of your induction of Arch⁓bishops, Bishops, and whole Clergie.., &c. is but a needlesse pompe of words. 1631Gouge God's Arrows iv. §3. 377 It may further be proved by that induction of particulars tending to this purpose which God himselfe bringeth in. 1655Fuller Ch. Hist. ii. vi. §42 That the Doctrine remained still sound and entire..will appeare by an Induction of the dominative Controversies. 1794Paley Evid. i. ix. (1817) 168 The persuasion produced by this species of evidence depends upon a view and induction of the particulars which compose it. 1842H. Rogers Introd. Burke's Wks. I. 40 It is valuable rather as a most extensive induction of facts, than as an instance of their successful application.
7. Logic.
a. The process of inferring a general law or principle from the observation of particular instances (opposed to deduction, q.v.).[Directly representing L. inductio (Cicero), rendering Gr. ἐπαγωγή (Aristotle), in same sense.] 1553T. Wilson Rhet. 111 We mighte heape many men together, and prove by large rehersall, any thyng that we would, the whiche of the logicians is called induction. 1613Purchas Pilgrimage (1614) Ep. Ded. ⁋iii, Others may hence learne by that most laborious, though not most learned Argument of Induction, two lessons fitting these times. 1656Stanley Hist. Philos. v. (1701) 182/1 Induction is every method of reason which proceedeth either from like to like or from singulars to generals. 1734Berkeley Analyst §19 You must take up with Induction, and bid adieu to Demonstration. 1812–16Playfair Nat. Phil. I. 2 It is from induction that all certain and accurate knowledge of the laws of nature is derived. a1862Buckle Misc. Wks. I. 41 Logic, considered as a science, is solely concerned with induction; and the business of induction is to arrive at causes. 1876Fowler Induct. Logic (ed. 3) Pref., Induction..may or may not employ hypothesis, but what is essential to it is the inference from the particular to the general, from the known to the unknown.
b. An act or instance of induction; the result of this; a conclusion derived from induction; formerly used in the wider sense of ‘inference’.
c1440J. Capgrave Life St. Kath. v. 1923 The hill in whiche god ȝaf the wrytyn lawe On-to the Iewes, ledeth to that perfeccyon Of crystis gospell..Paule in his bookis maketh swyche induccyon; He seyth it longeth to Ierusalem as in seruage With alle his children heere in pylgremage. c1530L. Cox Rhet. (1899) 49 He treateth of the fourme of Sillogismes, Enthimemes and Inductions. 1587Golding De Mornay xxvi. 396 We would haue [God] to vse Inductions as Plato doth, or Syllogismes as Aristotle doth. 1697tr. Burgersdicius his Logic II. xi. 46 In an induction..it's proved that animals void of bile are long-liv'd, because a man, a horse, an ass, &c., are long-liv'd. 1727–41Chambers Cycl. s.v., The conclusion of a syllogism, is an induction made from the premises. 1833H. Martineau Briery Creek iv. 86 They look..into the evidence of circumstance, and learn to make an induction for themselves. 1868W. R. Greg Lit. & Social Judgm. 313 The contrast between his wide inductions and the apparently flimsy foundation on which they are made to rest. 1869Fowler Induct. Logic i. 1 [This] is an inference of that particular character which is called an Inductive Inference or an Induction.
8. Math. (See quot. 1875.)
1838Penny Cycl. XII. 466/1 An instance of mathematical induction occurs in every equation of differences, in every recurring series, &c. 1875Todhunter Algebra (ed. 7) xxxiii. §484 The method of mathematical induction may be thus described: We prove that if a theorem is true in one case, whatever that case may be, it is true in another case which we may call the next case; we prove by trial that the theorem is true in a certain case; hence it is true in the next case, and hence in the next to that, and so on; hence it must be true in every case after that with which we began.
9. a. The action of bringing on, bringing into existence or operation, producing, causing. Chiefly Med. spec. Induction of labour.
1660Stanley Hist. Philos. ix. (1701) 403/2 The induction of sickness is the expulsion of health. 1835I. Taylor Spir. Despot. iii. 108 The gradual induction of political, ecclesiastical and moral changes. 1840Lancet 7 Nov. 225/1 (heading) Induction of premature labour. 1865Reader 1 Apr. 374/3 Abuse of tobacco is far more operative in the induction of this paralysis than alcohol. 1877Erichsen Surg. I. 23 The time required for the induction of the anaesthetic state varies. 1916G. P. Shears Obstetrics xxvi. 567 By the induction of abortion is meant the artificial interruption of pregnancy during the first twenty-eight weeks; i.e., before the fœtus becomes viable. The artificial interruption of pregnancy at any subsequent period is known as the induction of labor. 1962Lancet 6 Jan. 6/2 The failure-rate was decidedly high when induction of labour was started after the calculated date for confinement had passed. 1968D. C. Bethea Introd. Maternity Nursing ix. 120 Inductions may also be done for the convenience of the mother and/or the doctor.
b. Embryol. The determination of the development or differentiation of an embryonic region into a particular morphogenetic pattern by the influence or activity of another embryonic region; an instance of this.
1928Biol. Abstr. II. 686/2 In the small yolk-plug stage both the median and paramedian parts of the posterior 2/3 of the gut roof are capable of induction. 1935Discovery May 136/2 If..an organisation centre is grafted out of its usual place in an egg into new surroundings it will cause those new surroundings to develop into a complete embryo or complete organ. This ‘induction’ of a new embryo involves both sorts of embryological change; the production of new sorts of tissues..and the arrangement of those tissues. 1950L. G. Barth tr. Brachet's Chem. Embryol. x. 397 The middle layer..gave good inductions in 16 per cent of the cases. 1958B. M. Patten Found. Embryol. vi. 134 Experimental studies..have yielded extraordinarily interesting information as to the way one part of a developing embryo may influence the differentiation of other parts. When this occurs it is spoken of as induction. 1960B. I. Balinsky Introd. Embryol. vi. 169 The result may be expressed as a percentage of successful inductions. 1962T. W. Torrey Morphogenesis Vertebr. xviii. 481 Neural induction has been shown to occur in vertebrates other than amphibians.
c. Biochem. An increase in the rate at which an enzyme is synthesized by a cell (esp. in a micro-organism), or the initiation of its synthesis, as a result of the exposure of the cell to some specific substance (the inducer).
1947Growth XI. 242 Where the enzymes have not been obtained in pure crystalline state.., the evidence must come mainly from a study of the specificity of the phenomenon of induction. 1951Biochim. & Biophys. Acta VII. 599 These observations are incompatible with all hypotheses which imply that the induction is connected..with the activity of the enzyme. 1953Cohn et al. in Nature 12 Dec. 1096/1 It might prove unpractical to abandon the use of the term ‘enzyme adaptation’ altogether at this stage; but we should like to suggest that..a more accurate and significant terminology be employed. We therefore propose the following terms and designations; previously used terms are placed in parenthesis. A relative increase in the rate of synthesis of a specific apoenzyme resulting from exposure to a chemical substance is an ‘enzyme induction’ (enzyme adaptation). Any substance thus inducing enzyme synthesis is an enzyme ‘inducer’. An enzyme-forming system which can be so activated by an exogenous inducer is ‘inducible’, and the enzyme so formed is ‘induced’ (adaptive). Although many compounds can act both as inducer and substrate, the terms are not equivalent. Certain substrates for induced enzymes are not inducers, while some inducers cannot function as substrates of the enzymes the formation of which they elicit. 1966E. R. M. Kay Biochem. xxvii. 357 By many mechanisms of feedback control, repression, and induction, enzyme levels can be regulated in accord with the metabolic demands of the cell. 1971Nature 26 Nov. 177/2 Substrate induction of enzymes (that is, their synthesis in response to the presence of their substrates) is now commonplace in microorganisms and not infrequent in higher animals.
d. Biol. The initiation of the lytic cycle in a bacterium carrying a prophage; the process of inducing a bacterium that contains a prophage.
[1950A. Lwoff et al. in Ann. de l'Inst. Pasteur LXXIX. 817 Entre l'induction et la libération du bactériophage, il s'écoule de quarante-cinq à quatre-vingts minutes. 1951Jrnl. Bacteriol. LXII. 302 High titer stocks of this phage were obtained from K12 by induction of phage production with UV (the Lwoff effect). ] Ibid. 304 The plaque count rises..to a number equal to the colony count before induction.1953Cold Spring Harbor Symp. Quant. Biol. XVIII. 101/2 In 1950, Lwoff, Siminovitch and Kjeldgaard showed that..irradiation of cultures of lysogenic Bacillus megatherium with ultraviolet light greatly increased the proportion of bacteria producing phage... This phenomenon is called induction. 1959Jacob & Wollman in Burnet & Stanley Viruses II. ix. 326 It makes it possible to compare phage development in the same phage-bacterium system, whether after infection of sensitive bacteria, or after induction of lysogenic bacteria. 1959Jrnl. Molecular Biol. I. 177 When the reverse mating ({male} non-lysogenic × {female} λ-lysogenic) is performed, zygotic induction does not occur. 1968Echols & Joyner in H. Fraenkel-Conrat Molecular Basis Virol. vi. 557 The treatments which produce induction of wild-type prophages are rather diverse (e.g., UV irradiation, growth in mitomycin C, thymine deprivation of a thymine requiring bacterium).
10. Electr. and Magnetism.
a. The action of inducing or bringing about an electric or magnetic state in a body by the proximity (without actual contact) of an electrified or magnetized body.
The terms induce and induction were originally employed apparently to avoid the use of terms involving any theory of the nature of the action involved. The medium of communication was later held to be, as in the case of other forms of energy, the intervening ether.
electrodynamic induction or voltaic induction, the production of an electric current (induced current) by the influence of another independent electric current. electromagnetic induction, the production of a state of magnetic polarity in a body near or round which an electric or galvanic current passes, or the generation of an electric current by the action of a magnet (the latter called by Faraday, more properly, magneto-electric induction). electrostatic induction, the production of an electrical charge upon a body by the influence of a neighbouring body charged with statical electricity, as exemplified in Volta's electrophorus. magnetic induction, the production of magnetic properties in iron or other substances when placed in a magnetic field, as when a bar of soft iron is magnetized by a neighbouring magnet. mutual induction, the reaction of two electric circuits upon each other; self-induction, the reaction of different parts of the same circuit upon one another.
1801Encycl. Brit. Suppl. I. 572/2 (marginal note) A neutral body attracted, because rendered electrical by induction. 1812Sir H. Davy Chem. Philos. 132 To produce a succession of effects both conductors must be brought near bodies connected with the ground, which gain the opposite state, in consequence of what may be called induction. 1830Herschel Stud. Nat. Phil. 329 The communication of magnetism from the earth to a magnetic body, or from one magnetic body to another, is performed by a process to which the name of induction has been given. 1832Faraday Exp. Researches §1 in Phil. Trans. 125 The power which electricity of tension possesses of causing an opposite electrical state in its vicinity has been expressed by the general term Induction; which, as it has been received into scientific language, may also with propriety be used in the same general sense to express the power which electric currents may possess of inducing any particular state upon matter in their immediate neighbourhood. Ibid. §58. 139, I propose to call the agency thus exerted by ordinary magnets, magneto-electric or magnelectric induction. §59 The only difference which powerfully strikes the attention as existing between volta-electric and magneto-electric induction, is the suddenness of the former, and the sensible time required by the latter. 1870Tyndall Lect. Electr. 14 This forcible separation of the two fluids of a neutral conductor, by the mere proximity of an electrified body, is called electric induction. Bodies in this state are also said to be electrified by influence. 1892S. P. Thompson Dynamo-Elect. Mach. (ed. 4) 83 We know that every electric current possesses a property sometimes called ‘electric inertia’, sometimes called ‘self-induction’, by virtue of which it tends to go on, and that it is in the current's own magnetic field that this inertia of self-induction resides. Ibid. 102 Mutual induction between adjacent parts is of enormous importance in alternate current machines.
b. (Also magnetic induction.) Magnetic flux or (more commonly) flux density, by virtue of which an electric current experiences a magnetic force; as flux density, it is a vector quantity whose magnitude at any point is the magnetic force exerted per unit length on a conductor carrying unit current in the direction that gives rise to the maximum force, and whose direction is normal to those of the current and the force. Also (electric induction), electric flux or flux density, = displacement 2 d (now somewhat rare). line of induction, one of the imaginary lines conceived as representing, by their direction and number, the induction at each point throughout a region.
The C.G.S. unit of magnetic induction (flux density) is the gauss; in the International System of Units the tesla (= 10,000 gauss) is used.
1855J. C. Maxwell in Trans. Cambr. Philos. Soc. (1864) X. 49 The unit cells in this case are portions of space in which unit of magnetic quantity is produced by unity [sic] of magnetizing force. The length of a cell is therefore inversely as the intensity of the magnetizing force, and its section is inversely as the quantity of magnetic induction at that point. Ibid. 50 If a closed conductor move transversely to the lines of magnetic induction..there will be no current. 1861― in Phil. Mag. XXI. 168 The total amount of magnetic induction through a closed surface surrounding the pole of a magnet, depends entirely on the strength of that pole. 1873― Treat. Electr. & Magn. I. i. ii. 77 If dS is the element of the surface, the electric displacement through dS will be..KR cos ε dS/4π. Since we do not at present consider any dielectric except air, K = 1. We may..avoid introducing at this stage the theory of electric displacement, by calling R cos ε dS the Induction through the element dS. Ibid 85 We have used the phrase Lines of Force because it has been used by Faraday and others. In strictness, however, these lines should be called Lines of Electric Induction. Ibid. II. iii. ii. 24 The three vectors, the magnetization ℑ, the magnetic force 𝔥, and the magnetic induction 𝔅 are connected by the vector equation 𝔅 = 𝔥 + 4 πℑ. 1879Encycl. Brit. VIII. 75/2 For ‘number of lines of force’ may of course be substituted the equivalent expressions, ‘induction through the circuit’, or ‘surface integral of magnetic induction’. 1885O. Heaviside in Electrician 4 Sept. 311/1 There is a definite magnitude called by Maxwell ‘the magnetic induction’, which may well be called simply ‘the induction’. Ibid. 311/2 We pass to electric displacement, the analogue of magnetic induction (noting by the way that it had better not be called the electric induction..but be called the displacement). 1922Glazebrook Dict. Appl. Physics II. 449/2 Magnetic flux, the total amount of magnetic induction through a circuit, measured by the number of lines of induction which are linked with the circuit. 1925F. B. Pidduck Treat. Electr. (ed. 2) iii. 96 It is of some importance..to inquire what happens when the polarisation is not proportional to the electric force. We now require two vectors, P, E, not in general parallel to each other, to express the state of the medium at any point... If we define a vector D = E + 4πP, div D = o. The vector D is called the electric induction. 1938G. P. Harnwell Princ. Electr. & Electromagn. ix. 278 By analogy with the introduction of the electric field E in electrostatics it is convenient to introduce a vector B, known as the magnetic induction, which determines the force on a current element. The element of induction is defined by the equation dF1 = i1 dl1 × B2. 1957B. I. & B. Bleaney Electr. & Magn. v. 116 Both a magnet and a current-carrying coil are said to produce a magnetic induction B, which exerts forces on other coils or magnets. Ibid. 128 With a magnetic pole, H is the force vector, while the introduction of a uniform magnetic medium throughout the whole of space leaves the magnetic induction B due to a pole unchanged. In the case of a current, B is the force vector and introduction of a magnetic medium leaves H unchanged. If the magnetizable matter does not fill the whole of space, then it is the surface integral of B, the total normal induction, which remains unchanged in magnetostatics. 1962Corson & Lorrain Introd. Electromagn. Fields v. 179 If the current I is distributed in space with a current density J amperes/meter2, then I becomes J da and must be put under the integral sign... Thus, in the general case, the magnetic induction B at a point in space is given by B = (µ0/4π)∫τ(J × r1)/r2dτ, where the integration is carried out over any volume τ which includes all the currents.
11. Grammar. (See quot.)
1860Haldeman Anal. Orthogr. ix. 52 Induction is the influence of larger classes of words on smaller ones, causing uniformity and regularity in Grammatical inflections.
12. Chem. (See quot.)
1857Bunsen & Roscoe in Phil. Trans. R. Soc. CXLVII. 381 The act by which the resistance to combination is diminished, and the combining power thus brought into greater activity, we call Chemical Induction. 1892Morley & Muir Dict. Chem. III. 8/1 When H and Cl are mixed in equal volumes and exposed to sunlight, a measurable time elapses before chemical change begins. Bunsen and Roscoe, who examined this phenomenon, regard the mixture as resisting chemical change, and they used the term induction to express the gradual overcoming of this resistance. The term has also been used by Wright, who noticed a similar phenomenon in the reduction of metallic oxides by CO and H.
13. attrib. and Comb., as (sense 10) induction apparatus, induction current, induction machine, induction shock, induction spark; also induction accelerator = betatron; induction-balance, an electrical apparatus so contrived that the currents induced in the secondary wires of two induction-coils balance each other; induction-bridge, a form of induction-balance arranged on the principle of a Wheatstone's bridge; induction coil, an apparatus for producing electric currents by induction, consisting of two separated coils of wire generally surrounding a soft-iron core, the primary coil being connected with an external source of electricity, and having an arrangement for causing the electric current to vary in intensity, the effect of which is to produce a current of different character in the other or secondary coil; a coil in which an electric current is induced; an inductance coil; Teleph., a transformer in a telephone comprising two coils with a common core; induction compass = inductor compass; induction furnace, a furnace for melting metal by means of induction heating; induction generator, an induction motor driven at a greater speed than its synchronous speed, so that it acts as a generator; induction hardening, hardening of ferrous metal by means of induction heating followed by quenching; induction heater, an apparatus for the induction heating of objects; induction heating, in which an alternating current is made to induce heating currents in the substance or object to be heated or (less commonly) in its container; induction motor, an a.c. electric motor in which the torque or force is due to the interaction between a moving magnetic field produced by stationary primary windings and currents induced by this field in moving secondary conductors; (sense 12) induction period Chem., the time elapsing between the initiation of a chemical reaction and the production of detectable amounts of the product or products; (sense 3) induction-pipe, the pipe through which the live steam is introduced into the cylinder of a steam-engine; induction-port, the opening by which steam passes from the steam-chest into the cylinder; induction valve, the valve which controls the passage of steam into the cylinder.
1940D. W. Kerst in Physical Rev. LVIII. 841/2 Of several suggestions which have been made for naming the apparatus, *induction accelerator seems to be the shortest descriptive one. 1958Condon & Odishaw Handbk. Physics ix. ix. 154/2 To make this device practical, it is necessary only to restrain the beam to a closed path around the flux and to maintain it in a stable orbit over some thousands of revolutions. Credit for the solution of the latter problem goes to D. W. Kerst, who built the first successful induction accelerator or ‘betatron’ in 1940.
1855–7H. M. Noad Man. Electr. II. 728 The *induction apparatus as at present constructed by M. Ruhmkorff is shown in Fig. 395.
1879D. E. Hughes in Proc. R. Soc. XXIX. 56 M. Dove..constructed an *induction balance, wherein two separate induction coils, each having its primary and secondary coils, were joined together in such a manner that the induced current in one coil was made to neutralize the induced current in the opposite coil, thus forming an induction-balance, to which he gave the name of differential inductor. Ibid., I have obtained a perfect induction balance which..allows us to obtain direct comparative measures of the force or disturbance produced by the introduction of any metal or conductor. 1889Fleming Alternate Current Transformer 247 Lord Rayleigh found it more convenient..to slightly alter the arrangement of the induction balance..B and I are a battery and interrupter, T is a telephone in the ‘bridge’.
1837Mag. Pop. Sci. III. 110 A lever has also been applied to move..the *induction-coil up and down along two magnetic bars. 1855–7Noad Man. Electr. II. 728 In 1851, M. Ruhmkorff of Paris brought the induction-coil to a far greater degree of perfection than it had hitherto attained by paying the greatest possible attention to the insulation of the secondary wire. 1876Preece & Sivewright Telegraphy 262 Each globe or tube ought to be tested from time to time with an induction-coil, or some other generator of electricity of high potential. 1885R. S. Culley Handbk. Pract. Telegr. (ed. 8) ix. 328 The current from the battery does not itself pass out to line, but through a local circuit formed by the primary wire of an induction coil. This coil has a core made of soft iron wires,..and is wound with two wires one over the other... Every variation of the battery current in the primary, produces a corresponding current in the secondary, but of a much higher potential; this last goes out to line, and acts on the distant receiver. Ibid. 329 The microphone, induction coil and battery, form the sending portion of the telephone. 1891J. W. Urquhart Dynamo Construction 9 (caption) The induction coils combined with the field magnet. 1896Allbutt's Syst. Med. I. 351, I shall speak of electrostatic methods, of treatment by the battery current, and of treatment by the induction coil current. 1943A. L. Albert Fund. Telephony vii. 142 When the receiver is removed..the battery causes direct current to flow through the transmitter and the primary of the transformer, often called in telephony an induction coil. 1966McGraw-Hill Encycl. Sci. & Technol. VII. 72/2 Still another type of induction coil, called a reactor, is really a one-winding transformer designed to produce a definite voltage drop for a given current.
1925Mech. Engin. XLVII. 796/2 Since to keep on the correct course it is only necessary to keep the pointer of the *induction compass indicator on zero, it is easier to read than the magnetic compass. 1931B. Jones Avigation ii. 18 The induction compass is a distant-reading magnetic compass, the part indicating the heading to the pilot being at a considerable distance from the part affected by the earth's magnetism.
1881Maxwell Electr. & Magn. II. 408 This diffusion and decay of the *induction-current is a phenomenon precisely analogous to the diffusion of heat. 1875Bennett & Dyer tr. Sachs' Bot. 689 Weak induction-currents act on the sensitive parts of the leaves of Mimosa..like concussion or contact.
1906A. Hiorth Brit. Pat. 28,960 (heading) Improved electrical *induction furnace with electrodes. 1951G. R. Bashforth Manuf. Iron & Steel II. ix. 251 When..it was decided to dispense with the iron core of the early induction furnaces, it was necessary to increase the frequency of the current in the primary coil.
1904G. T. Hanchett Alternating Currents xiv. 173 The *induction generator cannot generate its own magnetizing current, but must receive a reaction from the line which will permit the magnetizing current of displaced phase to flow in its fields. 1952G. V. Mueller Alternating Current Machines viii. 284 In an induction generator driven above synchronous speed with a negative slip..the rotor conductors are moving faster than the magnetic field of the stator.
1941Metals & Alloys Nov. 687/1 *Induction hardening has been applied to the surface of certain steel parts for modern tractor and road-building machinery. 1968E. N. Simons Outl. Metall. iii. ii. 142 The three main forms of surface hardening steel parts are carburizing, cyaniding, and nitriding... There are also the processes of flame hardening and induction hardening.
1919Electr. World 29 Mar. 634/1 (heading) High-power-factor *induction heaters. 1930Engineering 9 May 611/2 The electric resistance [heaters]..heated the chilled surface of the roll and were not so good as the induction heaters, which generated heat within the body of the roll.
1919H. P. Tiemann Iron & Steel (ed. 2) 153 Induction furnace (*induction heating). 1937Metals & Alloys May 149/1 Applications of induction heating..now being installed..include..hardening of metal surfaces by quenching after induction heating. 1954J. W. Cable Induction & Dielectric Heating xii. 319 Many types of furnaces use induction heating as an indirect source of heat... Installations using graphite crucibles, which extract energy from the magnetic field and transfer it to the charge, fall in this general classification. 1959Engineering 13 Feb. 210/1 Plastics to plastics welding is most easily performed by high frequency induction heating. 1962G. R. Bashforth Manuf. Iron & Steel (ed. 2) IV. ii. 58 Induction heating differs from the conventional methods of heating metallic components by virtue of the fact that the heat is generated within the material itself without the surface of the material coming into contact with the heating media.
1896Westm. Gaz. 7 May 8/2 A small Wimshurst *induction machine.
1897Electrician 17 Sept. 688/1 (heading) A 400 H.P. *induction motor. 1918P. Kemp Alternating Current Electr. Engin. xxvi. 394 On account of the fact that it must run at a speed rather less than that of synchronism, the induction motor is sometimes termed an asynchronous motor. 1962Newnes Conc. Encycl. Electr. Engin. 492/1 In its basic form the induction motor is essentially a constant-speed motor: the variation in speed from no load to full load when running normally near synchronous speed is only a few per cent. 1971E. R. Laithwaite Linear Electr. Motors i. 7 (caption) Imaginary process of unrolling a conventional motor to obtain a linear induction motor. 1973Nature 9 Feb. 359/2 It is now feasible both to levitate and to propel a hovertrain using only a linear induction motor.
1902Proc. R. Soc. LXX. 74 The *induction and deduction periods follow as a necessity from the same general thermodynamic conceptions. 1924H. S. Taylor Treat. Physical Chem. II. xviii. 1219 The induction period was not a function of the oxygen content of the gas—this only retarded the reaction velocity. 1953Frost & Pearson Kinetics & Mechanism viii. 156 The duration of the induction period, arbitrarily taken as the time to reach the point of inflection on the C [sc. concentration of product] versus t [sc. time] curve..is easily seen to be equal to the time for B [sc. concentration of intermediate] to reach its maximum value. 1970Induction period [see inhibition 3 b].
1875Bennett & Dyer tr. Sachs' Bot. 689 The number of *induction-shocks..appears to have no considerable influence on the action. 1878Foster Phys. i. ii. §2. 46 Induction-shocks, or at least galvanic currents in some form or other.
1865Intell. Observ. No. 36. 389 When the *induction spark is taken in air. 1870Proctor Other Worlds xii. 280 The spectrum of the induction spark.
1847Rep. Comm. Patents 1846 (U.S.) 87 The *induction valve is then closed, and an expansion valve simultaneously opened. 1859Rankine Steam-Engine (1861) 480 The admission and discharge of the steam take place through openings near the ends of the cylinder called ‘ports’, connected with passages called ‘nozzles’, which are opened and closed by induction and eduction valves. |