| 释义 |
oscillation|ɒsɪˈleɪʃən|
[ad. L. oscillātiōn-em, n. of action from oscillā-re to swing. Cf. Fr. oscillation (1701 in Hatz.-Darm.).]
1. a. The action of oscillating; swinging to and fro like that of a pendulum; a periodic movement to and fro, or up and down.
angular oscillation, gyration. axis of oscillation: see axis 6. centre of oscillation: see centre 16.
1658Phillips, Oscillation, a hanging or tottering motion, a swinging upon a rope whose ends are tyed to several beams. 1713B. Taylor in Phil. Trans. Abr. VI. 7 (heading) Of Finding the Centre of Oscillation. 1726[see oscillate 1]. 1822J. Imison Sc. & Art I. 80 Observing the oscillations of a lamp which was hung from the ceiling. 1831Brewster Newton (1855) I. xiii. 362 The tides are the consequence of the perpetual oscillation of the waters of the ocean. 1865Livingstone Zambesi xxv. 535 Evidences of the oscillations of land and sea. 1871B. Stewart Heat §77 The rate..of a watch depends upon the time of oscillation of its balance-wheel.
b. In Acoustics, sometimes = vibration; sometimes = beat n.1 8. rare.
2. a. fig. A swaying to and fro between two states, opinions, principles, purposes, etc.; alternating variation, fluctuation, wavering.
1798Malthus Popul. (1817) I. 27 The same retrograde and progressive movements, with respect to happiness..This sort of oscillation will not probably be obvious to common view. 1809–10Coleridge Friend (1865) 216 This oscillation of political opinion. 1876Rogers Pol. Econ. iii. (ed. 3) 29 There are always oscillations in price. 1884Bower & Scott De Bary's Phaner. 42 Oscillations and transitions between the related types are by no means rare.
b. Psychol. Fluctuation of attention or mental efficiency.
1895Amer. Jrnl. Psychol. VII. 84 Schwankungen der Aufsmerksamkeit, oscillations or fluctuations of the attention. 1927C. S. Spearman Abilities of Man xix. 319 We may now conveniently turn to a phenomenon which may be described as oscillation of cognitive efficiency, and which probably has an intimate connection with..fatigue. Ibid. 326 Here in oscillation, then, we have come upon a new single and universal factor, a third in addition to g and perseveration. 1943C. L. Hull Princ. Behavior xvii. 306 One may reasonably conjecture that it was produced by some factor in the experimental situation other than the primitive oscillation tendency. 1950P. E. Vernon Struct. Human Abilities viii. 89 An Oscillation factor in rate of fluctuation of reversible perspective figures.
3. Electronics. A rapid alternation in the direction of flow of a current; the state of a circuit in which this is occurring; also, a rapidly varying electromagnetic field produced by such a current.
1853tr. H. Helmholtz in Sci. Mem. Trans. Foreign Acad. (Nat. Philos.) 143 It is easy to explain this law if we assume that the discharge of a battery is not a simple motion of the electricity in one direction, but a backward and forward motion between the coatings, in oscillations which become continually smaller until the entire vis viva is destroyed by the sum of the resistances. 1885Electrician 18 Dec. 106/1 It shows that if the resistance be reduced to nothing, whilst the coefficient of self-induction of the circuit is finite..the oscillations continue for ever undiminished in strength. 1911Encycl. Brit. XXVI. 532/2 The transmitting antenna wire is alternately charged to a high potential and discharged with the production of high frequency oscillations in it. 1932E. V. Appleton Thermionic Vacuum Tubes 102 Since the applied anode potential is negative no anode current flows unless oscillations are present. 1951A. Sheingold Fund. Radio Communication xii. 254 The desirable operational properties of an oscillator may include the property of being self-starting, the ability to maintain continuous oscillation, [etc.]. 1959R. L. Shrader Electronic Communication xii. 307 If it is desired to prevent a radio circuit from going into oscillation, it may be necessary to introduce degeneration in it, or neutralize it. 1975Barron & Joyce Electricity xv. 450 The electrical oscillations of a capacitor-inductor loop can be used to transmit oscillations of radio frequency.
4. Math.
a. The difference between the greatest and the least values of a function in any given interval.
1893Harkness & Morley Treat. Theory of Functions ii. 49 If f(x) be a discontinuous function of x, which is always finite between a and b, its values within an interval δ will have an upper and a lower limit. The difference between these upper and lower limits is named the oscillation of the function. 1937Michell & Belz Elem. Math. Analysis I. i. 73 If the focal bounds are unequal, the sequence is said to be divergent and to have a finite oscillation. Ibid. 91 The functions sin x, (sin x)/x. The former function has a finite oscillation -1 to +1 at x = +∞. 1973G. Klambauer Real Analysis iii. 75 The oscillation is a monotone mapping in the sense that if J1 and J2 are bounded open intervals and J1⊂ J2, then ω(f; J1) {slle} ω(f; J2).
b. Variation consisting of alternate increase and decrease (cf. oscillate v. 4).
1908T. J. I'A. Bromwich Introd. Theory Infinite Series ii. 22 If all the terms..of the series are positive, the sequence..steadily increases; and so..the series σan must be either convergent or divergent; that is, oscillation is impossible. 1968Fox & Mayers Computing Methods for Scientists & Engineers vii. 129 A characteristic of a good approximation is a type of oscillation property, effectively produced by the presence of n + 2 alternating maxima and minima of the error.
5. attrib., as † oscillation circuit (now called oscillator circuit), oscillation detector, † oscillation valve; oscillation constant (see quot. 1940); † oscillation transformer = jigger n.1 5 p.
1906A. F. Collins Man. Wireless Telegr. ii. 32 The resistance of an oscillation circuit is practically negligible. 1923― Everybody's Wireless Bk. xii. 198 The resistance of an oscillation circuit, whether it is a closed circuit or the aerial, must be made as low as possible in order to let the high frequency currents oscillate in it freely.
1908C. C. F. Monckton Radio-Telegr. ii. 36 For different circuits, as long as the oscillation constants are the same the natural periods of vibration are the same. 1940Chambers's Techn. Dict. 601/1 Oscillation constant, the square root of the product of the inductance (in henries) and the capacitance (in farads) of a resonant circuit.
1908J. A. Fleming Elem. Man. Radiotelegr. ix. 324 It is necessary to employ in the receiving circuit an oscillation detector which is..not merely affected by oscillations, but affected to some extent proportionately to their amplitude.
1906Oscillation transformer [see jigger n.1 5 p]. 1923A. F. Collins Everybody's Wireless Bk. viii. 130 There are two distinct types of tuning coils used for continuous wave sending sets, and these are (1) the helix, or close-coupled coil, and (2) the oscillation transformer, or loose-coupled coil. The former gives much better results.
1906Proc. Physical Soc. XX. 177 (heading) The construction and use of oscillation valves for rectifying high-frequency electric currents. 1908J. A. Fleming Elem. Man. Radiotelegr. vi. 205 A very simple but effective form of oscillation valve was invented by the author in 1904. |