| 释义 |
traction|ˈtrækʃən|
[ad. med.L. tractiōnem (Albertus, a 1250), n. of action from trahĕre, tract-um to draw. So F. traction, Sp. traccion, Pg. tracção, It. trazione.]
1. a. The action of drawing or pulling; draught: opposed to pulsion or pushing, and (in Dynamics) to pressure.
force of traction, the force exerted in or required for traction. line of traction, the line along which this force acts. angle of traction, the angle between the line of traction and the surface along which the body is drawn.
1656tr. Hobbes' Elem. Philos. (1839) 343 Motion is distinguished into pulsion and traction. 1837Whewell Hist. Induct. Sc. (1857) II. 32 Bodies, on which pressure and traction are exerted. 1843Penny Cycl. XXV. 109/2 When the angle of traction..is 15 or 16 degrees, a horse pulls with good effect... An example of the force of traction exerted by steam. 1868Duncan tr. Figuier's Insect W. Introd. 25 The cockchafer..possesses a power of traction equal to more than 14 times its own weight.
b. Phys. and Path. A drawing or pulling of a part or organ (in an animal or plant) by some vital process, as the contraction of a muscle, or the tension of some adherent part.
1615Crooke Body of Man 544 In the traction of the first the lid is depressed; in the traction of the latter it is lifted vp. 1669Holder Speech 163 The Malleus, being fixed to an extensible Membrane, follows the Traction of the Muscle. 1802Paley Nat. Theol. xi. (ed. 2) 222 The claws do their office in keeping hold of the support..by the traction of the tendons, in consequence of the attitude which the legs and thighs take by the bird sitting down. 1875Bennett & Dyer Sachs' Bot. 728 The layers which are less turgid and grow more slowly are exposed to a passive traction which promotes their growth. 1876Clin. Soc. Trans. IX. 192 There was..a slight..traction of face to the right side when the patient laughed.
c. A drawing or pulling movement used in massage, etc.: in quot. 1841 applied to the use of metallic tractors (see tractor 1).
1841Fraser's Mag. XXV. 89 The effects produced by traction, or the rubbing of metallic tractors, tipped with little lumps of wax, on the parts affected by pain, are well known. 1887D. Maguire Art Massage iii. (ed. 4) 51 Tractions are movements used on the articulations by pulling one part while holding the other. 1901Westm. Gaz. 28 Nov. 10/2 Traction of the tongue—that is, moving it about in a rhythmical manner—has produced wonderful results in restoring the apparently dead (especially children) to life. Dr. Laborde, of Paris, is the discoverer of the treatment.
d. fig. Drawing, attraction, attracting power.
1649E. Reynolds Hosea v. 18 Our conversion and sanctification comes from..a supernaturall and omnipotent traction. a1711Ken Christophil Poet. Wks. 1721 I. 425 His Love in Suavities distills, Preventions, Tractions sweet, Devout Christ-hymning Heat. 1883A. H. Welsh Eng. Lit. I. vi. 384 He [Macbeth] feels the resistless traction of fate.
e. Med. A sustained pull applied to a part of the body to maintain the positions of fractured bones following reduction of the fracture; the state of being subjected to such a pull; so in traction.
1885Boston Med. & Surg. Jrnl. CXII. 545/1 The high pulleys..were used, as before, for oblique traction from the knee bands. 1939W. C. Campbell Operative Orthopedics ii. 97 The majority of apparatus for either suspension or traction of the upper extremity is extremely cumbersome. 1962Lancet 13 Jan. 61/1 The patient had previously been treated by neck traction and by prolonged physiotherapy, without benefit. 1973‘D. Shannon’ Spring of Violence (1974) iii. 46 They had one leg in traction. 1981R. S. H. Browne Basic Facts in Orthopaedics 95 Traction is used to overcome painful muscle spasm.
2. spec. The drawing of vehicles or loads along a road or track; esp. in reference to the power by which this is done, as horse traction, steam traction, electric traction.
1822J. Imison Sc. & Art I. 27 Dividing the beam..that the point of traction may be as much nearer to the stronger horse. 1826J. Adamson Sk. Inform. Rail-Roads 38 Every change..has..added to our powers of tracktion. 1902Daily Chron. 1 July 4/6 The three stages are horse-traction, steam traction, and electric traction.
b. transf. (a) A vehicle driven by some special power, as a motor car. nonce-use. (b) Stock Exchange. Stocks connected with traction, as tramways, etc.
1896Westm. Gaz. 13 Nov. 5/2 They attended the Court, having ridden in ten miles on the offending traction. 1903Daily Chron. 5 Nov. 8/7 The victory for Tammany early in the session reflected strength in tractions and other municipal utility stocks. 1905Ibid. 4 May 5/7 Prices worked lower. Coalers and tractions showed some strength.
3. Short for force of traction (as a measurable quantity); the amount of rolling friction (also traction of adhesion) as measuring this (quot. 1877).
1825J. Nicholson Operat. Mechanic 666 If the speed be increased from six miles an hour to eight, the horses have by no means 1-4th less work to do, supposing the friction a constant quantity, and the traction consequently the same. 1838Civil Eng. & Arch. Jrnl. I. 350/1 A dynamometer, by which the traction might be measured with considerable accuracy. 1877Knight Dict. Mech., Traction, the adhesive friction of a wheel on a rail, a rope on a pulley, etc.
4. Physical Geogr. The rolling and bumping of particles along the ground by a stream or the wind.
1914G. K. Gilbert in Prof. Papers U.S. Geol. Surv. No. 86. 15 This second division of current transportation is called by certain French engineers entraînement but has received no name in English. Being in need of a succinct title, I translate the French designation..by the word traction. 1954W. D. Thornbury Princ. Geomorphol. iii. 48 Traction involves the partial support of the material being transported by the buoyancy of the water or air but consists chiefly of the rolling, pushing, and dragging along of rock particles which are too large to be lifted. 1968R. W. Fairbridge Encycl. Geomorphol. 319/2 Wind carries rock and organic debris by traction, saltation and suspension. 1972R. J. Small Study of Landforms ii. 40 In areas where..chemical weathering is very active, streams may contain much of their load in solution, and traction, saltation and suspension may be correspondingly small.
5. attrib. and Comb., as traction company, traction installation, traction instrument, traction movement, traction power; traction aneurism, diverticulum (see quots.); traction-gearing, an inexact name for friction-gearing (friction n. 5); traction-load, the weight of a locomotive engine or motor car which presses the driving-wheels upon the rail or ground so as to produce the requisite adhesive friction and prevent the wheel from slipping; traction motor, an electric motor designed for use in traction; traction splint (Surg.), a splint with an attachment for pulling upon the limb; traction-wheel, a driving-wheel.
1891Cent. Dict., *Traction-aneurism. 1899Syd. Soc. Lex., T[raction] aneurism, an aneurism most commonly seen in children, due to traction of the aorta from an incompletely atrophied ductus Botalli.
1897Allbutt's Syst. Med. III. 364 *Traction deverticula generally occur on the anterior wall of the œsophagus. 1899Syd. Soc. Lex., T[raction] diverticulum, a circumscribed sacculation of the œsophagus from the traction of the circum-œsophageal adhesions.
1877Knight Dict. Mech., *Traction-gearing, an arrangement for turning a wheel and its shaft by means of friction or adhesion.
1879St. George's Hosp. Rep. IX. 501 On three eyes a *traction instrument was used.
1900Parshall & Hobart Electr. Generators i. 232 For satisfactory commutation, *traction motors are designed with very high magnetisation at full load. 1950Times Rev. Industry Sept. 25/1 The other two [locomotives] will have single-phase a.c. traction motors of special design. 1969R. W. Smeaton Motor Applic. & Maintenance Handbk. viii. 5 Traction motors are very ruggedly built.
1887D. Maguire Art Massage iv. (ed. 4) 106 Executing..some *traction movements.
1908Westm. Gaz. 13 Feb. 5/2 American machines..are geared so low as to give them a maximum of *traction power at the expense of speed.
1935Sun (Baltimore) 5 Apr. 3/2 The remedy..is use of ‘*traction splints’, devices for automatically pulling ends of broken bones together and holding them. 1976M. Machlin Pipeline xl. 443 He's got a bad break there. You'd better put that leg in a traction splint.
1877Knight Dict. Mech., *Traction-wheel, a wheel employed in drawing or impelling a vehicle, as the driving-wheel of a locomotive or traction-engine.
Hence ˈtractional a., of or pertaining to traction.
1877Knight Dict. Mech. s.v. Traction, The tractional surface of a driving-wheel is the face of its perimeter. |