| 释义 |
reˈactive, a. and n.|riːˈæktɪv|
[f. react v.1 + -ive. Cf. F. réactif (18th c.), It. reattivo.]
A. adj.
†1. Repercussive, echoing. Obs.—1
1712Blackmore Creation 357 Ye fish, assume a voice, with praises fill The hollow rock, and loud reactive hill.
2. Acting or operative in return.
1794G. Adams Nat. & Exp. Philos. III. xxi. 103 Every body that acts, is at the same instant both active and re⁓active. 1851H. Spencer Soc. Stat. 318 We have to consider, not only what is done for the afflicted, but what is the reactive effect upon those who do it.
3. Path.
a. Supervening on a previous opposite state; due to reaction. Also reactive formation = reaction formation s.v. reaction 5; reactive inhibition, the inhibiting effect of the supervention of fatigue or boredom on the response to a stimulus.
1822–34Good's Study Med. (ed. 4) IV. 434 The patient..was not rendered faint by the re-active glow that ensued upon his quitting the water. 1885–8Pye-Smith Fagge's Princ. Med. I. 51 Such patients..sometimes pass into a condition of reactive pyrexia. 1925J. Strachey tr. Freud's Case of Hysteria in Coll. Papers III. 67 Repression is often achieved by means of an excessive reinforcement of the thought contrary to the one which is to be repressed. This process I call reactive reinforcement. Ibid. 68 The thought which asserts itself exaggeratedly in consciousness and (in the same way as a prejudice) cannot be removed I call a reactive thought. 1943C. L. Hull Princ. Behavior xviii. 327 Uniform time intervals between reinforcements great enough to prevent the accumulation of appreciable amounts of reactive inhibition. 1968Globe & Mail (Toronto) 3 Feb. 11/6 These young people can join ‘negative identity’ groups and become..therapeutically involved in extreme reactive kinds of activity. 1974Chaplin & Krawiec Systems & Theories of Psychol. vii. 263 In and of itself fatigue will generate a form of inhibition which Hull calls reactive inhibition, and the animal will cease to respond. 1975Way Suppl. No. 25. 67 Dynamic psychology might interpret this as evidence for reactive formation, which is a technical term suggesting that we control an unacceptable impulse by exaggerating the opposite tendency. 1977G. H. Sage Introd. Motor Behav. (ed. 2) xvi. 359 The first of these is an inhibition (reactive inhibition) caused by a reluctance to repeat a response.
b. Recuperative; responsive (to a stimulus); characterized by reaction to a stimulus.
1822–34Good's Study Med. (ed. 4) I. 704 There is no longer any rallying or reactive power remaining. 1896Allbutt's Syst. Med. I. 193 These granules are feebly reactive to light. Ibid. 293 Delicate children, with little reactive power. 1927C. Spearman Abilities of Man iv. 47 Stern's division of persons into the ‘spontaneous’ and the ‘merely reactive’. 1952M. K. Wilson tr. Lorenz's King Solomon's Ring xi. 171 A few birds—usually old, strongly reactive ones— take off, emitting ‘Kiaw’ cries and thereby provoking the whole flock to leave the ground with them.
c. Psychol. Of mental illness: thought to be caused by reaction to environmental stress; exogenous; so reactive schizophrenic, a person with reactive schizophrenia (cf. process schizophrenia s.v. process n. 13 a).
1924A. A. Brill Bleuler's Textbk. Psychiatry xii. 537 Reactive depressions, which become aggravated to a mental disease, are quite rare in the light of present views. 1955McCarthy & Corrin Med. Treatment of Mental Dis. xix. 326 Reactive depressions are the mild, brief depressions, the result of situations depressing in themselves, and not out of proportion to circumstances. 1958H. Weiner in L. Bellak Schizophrenia iv. 157 Whether such reactive psychoses actually imply a different series of etiologic contributing factors, i.e., ‘non-organic’, is highly speculative. 1962Lancet 10 Jan. 105/1 Two were middle-aged men with anxiety states... The third was a middle-aged lady with a reactive depression. 1962Psychol. Bull. LIX. 329/1 Reactive schizophrenia indicates a good prognosis..with notable stress precipitating the psychosis. Ibid. 332/1 If the Rorschach diagnosis is followed, then it appears that reactive schizophrenics are not psychotic. 1965J. Pollitt Depression & its Treatment 95 The terms ‘endogenous’ and ‘reactive’..differentiate types of depression on the basis of presence or absence of an external cause. 1966I. B. Weiner Psychodiagnosis in Schizophrenia vi. 94 A group of process schizophrenics made no more frequent errors than the reactive schizophrenics. 1971Brit. Med. Bull. XXVII. 77/2 One school of thought..allocates such cases to a special category of ‘reactive psychoses’. 1974M. C. Gerald Pharmacol. xvi. 310 When the cause of depression can be identified,..we term this reactive or exogenous depression. 1976L. J. West et al. Treatment of Schizophrenia vi. 278 The good premorbid/bad premorbid, and process/reactive dimensions do seem to identify significant characteristics.
4. Characterized by reaction (sense 4).
1868Gladstone Juv. Mundi i. (1870) 24 The reactive tendency to preserve the text by recurrence to a standard. 1890Harper's Mag. June 77/1 He constantly inclined to reactive measures.
5. Chem.
a. Readily susceptible to chemical reaction.
1888Nature 22 Mar. 503/1 The unsaturated hydrocarbons..are..more reactive than the paraffins. 1942G. Wendt Chem. vii. 179 As in the other families of elements we shall meet, the lightest of the group—in this case fluorine—is the most reactive. 1957G. E. Hutchinson Treat Limnol. I. xi. 708 It is not clear, however, in what form this reactive iron is actually present in the lake water. 1972R. A. Jackson Mechanism iv. 78 A trapping or inhibiting agent may be insufficiently reactive towards a particular intermediate to divert it from its normal course of reaction, or the agent may react in such a way as to regenerate another reactive intermediate.
b. Of a process: involving chemical reaction.
1950Chem. Abstr. XLIV. 8190 (heading) Reactive diffusion in metals. 1960Ibid. LIV. 23646 The reactive diffusion in a system Nb-B is accomplished by diffusion of B atoms through the reaction products toward the metal. 1971New Scientist 8 Apr. 96/1 Reactive evaporation..is often used for depositing metal oxides. 1973R. L. Burwell in Basolo & Burwell Catalysis ii. 72 Ethylene is adsorbed by reactive adsorption. Perhaps it first adsorbs as a π-complex and then reacts to monoadsorbed ethane. 1978Felder & Rousseau Elem. Princ. Chem. Processes x. 384 In this chapter we show..how calculated enthalpies of reaction are incorporated in energy balances on reactive processes.
c. Of a dye or other colouring material: designed to react chemically with the substrate, usu. in order to become fixed.
1957Jrnl. Soc. Dyers & Colourists LXXIII. 238/2 The search for more practical methods of using reactive dyes has continued, and this work has now culminated in the production of a new range of dyes—the Procion (ICI) dyes—which are water-soluble but contain a reactive group capable of combining with cellulose under alkaline conditions. 1973Materials & Technol. VI. iv. 310 The direct, basic, sulphur, vat, azoic and reactive dyes are all suitable for colouring the fibre [sc. rayon]. a1977Harrison Mayer Ltd. Catal. 39/1 Reactive colours, a new range of leadless colours for underglaze, on-glaze or in-glaze decoration... On firing, these colours react with the glaze to give interesting and variegated effects.
d. Of coke or coal: having a high reactivity (sense b).
1963Economist 21 Dec. 1284/1 Reconciling the clean air policy with the British love of open fires means trying to produce enough smokeless fuel of the sort that can be burnt in the fireplaces of smokeless zones. But the Minister of Power now estimates that there will be a gap..between the demand for such ‘reactive’ smokeless fuels and the supply. 1974Encycl. Brit. Macropædia IV. 783/2 Coals of medium rank are used for low-temperature carbonization because they yield reactive cokes.
6. a. Electr. Possessing or pertaining to electrical reactance; spec. applied to the vector component of an alternating current (or voltage) which is 90° out of phase with respect to the associated voltage (or current), i.e. wattless; reactive power, the product of the voltage and the reactive current, or of the current and the reactive voltage; reactive volt-ampere, a unit of reactive power.
1892J. A. Fleming Alternate Current Transformer II. ii. 269 Reactive Coil or Dimmer.—This is a device used in alternating current work to serve the same ends as rheostats in direct current plants. 1892S. P. Thompson Dynamo-Electr. Machinery (ed. 4) xxii. 628 We have here two electromotive-forces, the impressed O A and the reactive A E..with their resultant the effective electromotive-force O E, with an angle E O A..between them. 1914J. H. Morecroft Continuous & Alternating Current Machinery vi. 205 The component of voltage 90° out of phase with the current we shall call the reactive component of the voltage or reactive voltage. 1916Standardization Rules Amer. Inst. Electr. Engineers 15 Reactive volt-amperes, the product of the reactive component of the voltage by the total current, or of the reactive component of the current by the total voltage. 1920Whittaker's Electr. Engineers's Pocket-Bk. (ed. 4) 222 The reactive current changes from leading to lagging as the field excitation is reduced. 1951W. Sluckin Princ. Alternating Currents ix. 225 In an induction motor, neglecting heating losses, the active component provides the useful mechanical power delivered by the motor, while the reactive component is associated with the production of the alternating magnetic field necessary for the operation of the motor. 1956C. S. Siskind Electr. Circuits xi. 265 The vertical component—the quadrature component—is EI sin θ. The latter, acting adversely to lessen the power factor, is expressed as the reactive volt-amperes, abbreviated R-va. 1961Listener 9 Nov. 768/2 There is also the problem, with direct current lines, of providing what is called the reactive power—power where the current is out of step with the voltage—for the operation of converter equipment. 1970J. Earl Tuners & Amplifiers iv. 83 The source itself can be mostly resistive or mostly reactive. 1978Gramophone May 1958/1 It is claimed to have an output of 100 watts RMS working into an 8-ohm inductive or reactive load.
b. Mech. and Acoustics. Possessing or pertaining to mechanical or acoustic impedance.
1934Olson & Massa Applied Acoustics ii. 32 (caption) Resistive and reactive air load per unit area on one side of a vibrating piston of radius R centimeters set in an infinite baffle. 1963[see impedance 2]. 1976A. H. Benade Fund. of Musical Acoustics xxi. 457/2 The other register hole on my special clarinet can be called a reactive register hole, i.e., an aperture in which the flow depends mainly on the inertia of the air moving through it.
7. Gram. (See quot.) rare.
1957R. W. Zandvoort Handbk. Eng. Gram. v. ii. 224 To express the speaker's reaction to a previous statement by the person addressed which is repeated by the speaker (reactive questions)... You can't catch me.—I can't, can't I? said Philip.
B. n. Chem. [ad. F. réactif.] A reagent. rare.
[1790Monthly Rev. III. 546 Chemical tests, or, as the French call them, reactives.] 1791Hamilton Berthollet's Dyeing I. i. ii. iv. 192 A chemist should be employed for preparing a proper reactive. 1887Browning Parleyings, C. Avison ix, Reviewing learnedly the list complete Of chemical reactives.
Hence reˈactively adv. So reˈactiveness (Webster 1847) = next.
1805Foster Ess. i. ii. 30 The living world..is re-actively throwing on him various moral influences and infections. 1860A. L. Windsor Ethica v. 285 A very irritable temper, that bore him reactively into close relationship with a few. |