| 释义 |
propagation|prɒpəˈgeɪʃən|
[a. F. propagation (13th c. in Hatz.-Darm.), or ad. L. prō-, propāgātiōn-em, n. of action f. prō̆pāgāre to propagate.]
The action of propagating.
1. a. The action of producing as offspring, or multiplying by such production; procreation, generation, reproduction.
a1450Mankind 181 in Macro Plays 7 Of þe erth & of þe cley we haue owur propagacyon. 1526Pilgr. Perf. (W. de W. 1531) 170 b, He that by naturall propagacyon hath generate or begoten vs. 1601Holland Pliny xvii. xiii. 515 The worke of nature, in sending out these sprigs, taught us the feat to couch and lay sets in the ground by way of propagation. 1781Burke Sp. Marriage Act Wks. X. 136 Matrimony is instituted not only for the propagation of men, but for their nutrition, their education, their establishment. 1857Henfrey Bot. §875 In the lower Algæ,..the plants are continually undergoing propagation by division of the constituent cells. 1883Goode Fish. Indust. U.S.A. 74 (Fish. Exhib. Publ.) The machinery for propagation [of fish] on a gigantic scale by the aid of steam.
†b. The action of peopling with offspring. Obs.
1662Stillingfl. Orig. Sacr. iii. i. §2 The propagation of the world after [the flood] by the Sons of Noah.
†2. That which is propagated; offspring, generation, breed, race. Obs.
1536Exhort. to the North 86 in Furniv. Ballads fr. MSS. I. 307 And with that noit content, hys mallys put in vre agaynes the trew lewes of hys propagation. 1596Warner Alb. Eng. xi. lxvii. (1612) 285 With Marrage, that legitimates our propagation. 1611Rich Honest. Age (Percy Soc.) 49 The Laconian women brought foorth a propagation of men of haughty courage.
†3. fig. Increase in amount or extent; enlargement; extension in space or time. Obs.
1603Shakes. Meas. for M. i. ii. 154 This we came not to, Onely for propogation of a Dowre Remaining in the Coffer of her friends. a1716South Serm. (1744) XI. ii. 39 The spoil and waste they had made..for the propagation of their empire, which they were still enlarging as their desires. 1741Middleton Cicero I. iii. 217 Not for the propagation of his own life.
4. Dissemination, diffusion, esp. of some principle, belief, or practice.
1588Reg. Privy Council Scot. IV. 266 The propagatioun of the trew..religioun. 1615Latham Falconry Epist., For the propagation of the noble sport. 1701Charter Will. III 16 June, [To] be one Body Politick and Corporate, in Deed, and in Name, by the Name of the Society for the Propagation of the Gospel in Foreign Parts. 1751Johnson Rambler No. 144 ⁋6 Calumny is diffused by all arts and methods of propagation. 1859Mill Liberty ii. 36 Forbidding the propagation of error. 1877Sparrow Serm. ix. 112 The main use of agencies..in connection with religion, is the propagation of the truth.
5. Transmission of some action or form of energy, as motion, light, sound, etc.
1656tr. Hobbes' Elem. Philos. (1839) 334 When..one body, having opposite endeavour to another body, moveth the same, and that moveth a third, and so on, I call that action propagation of motion. 1710J. Clarke Rohault's Nat. Philos. (1729) I. 191 The Propagation of Sound may very well be compared with Circles made in the Water, by throwing a Stone into it. 1804Sir J. Leslie (title) An Experimental Inquiry into the Nature and Propagation of Heat. 1849Noad Electricity (ed. 3) 138 We must consider the transference of the hydrogen to take place by the propagation of a decomposition through a chain of particles extending from the zinc to the platinum. 1854Pereira's Pol. Light 8 The Propagation of Light.—Light emanates, radiates, or is propagated in straight lines.
†6. The action of branching out as a shoot (L. propago); concr. a branch, ramification. Obs. rare.
1650Bulwer Anthropomet. 10 The nerves of the Taste descend from the third and fourth Propagations, and so diffuse themselves into the tongue.
7. Chem. In a chain reaction, the step or series of steps in which product molecules are formed or polymer chains lengthened, but which is self-perpetuating by virtue of the regeneration or relocation of reactive centres; e.g. in polymerization, reaction of a radical with a molecule of monomer to form a longer radical. Freq. attrib.
1928Proc. R. Soc. A. CXXII. 621 The conditions which govern the propagation of the stable reaction chains. 1940Ann. Rep. Progr. Chem. XXXVI. 74 When an active molecule possesses such a long lifetime, the rate of formation and destruction of these centres plays no part in the rate of polymerisation, which is then solely determined by the velocity of the propagation reaction. 1950Thorpe's Dict. Appl. Chem. (ed. 4) X. 88/1 This is followed by the propagation stage, in which successive additions of monomer molecules occur, maintaining an odd electron, characteristic of a free radical, at the end of the growing chain. 1964J. M. Crabtree et al. tr. V. N. Kondrat′ev's Chem. Kinetics of Gas Reactions ix. 613 The chain propagation processes involving HO2 radicals are important in the so-called slow oxidation of hydrogen which occurs..at relatively high pressures. 1973K. J. Saunders Org. Polymer Chem. i. 10 This new radical then adds further monomer molecules in rapid succession to form a polymer chain. In this propagation the active centre remains, being continuously relocated at the end of the chain.
8. attrib. and Comb., as propagation tray; propagation coefficient, constant, or factor Physics, the coefficient of the distance in an equation representing the propagation of a wave (quot. 1943 represents an equivalent def.); propagation function Physics, = propagator 3.
1943Gloss. Terms Telecommunications (B.S.I.) 7 Propagation coefficient, propagation constant, the natural logarithm of the vector ratio of the steady-state amplitudes of a wave at a specified frequency, at points in the direction of propagation separated by unit length.
1911J. A. Fleming Propagation Electr. Currents ii. 68, P is a complex quantity and therefore may be written in the form α+ jβ. It is called the Propagation constant of the line. 1963R. W. Ditchburn Light (ed. 2) ii. 28 The wave⁓length..is denoted by λ. An associated constant κ = 2π/λ is called the wavelength constant (or propagation constant). 1976G. R. Olhoeft in R. G. J. Strens Physics & Chem. of Minerals & Rocks 262 All of the material properties (other than geometric boundary conditions) which are important to the description of the propagation of an electromagnetic wave (or lack of propagation) are described in the propagation constant by the quantities µ, ε, and σ.
1958Condon & Odishaw Handbk. Physics iv. vii. 108/2 The solution is a plane wave..varying periodically in time with the frequency ν = ω/2π and advancing in the + x direction through space with a complex propagation factor γ = jω√ε*µ* = α + jβ .
1949Physical Rev. LXXVI. 770/1 Many of the properties of the integrals are analyzed using formal properties of invariant propagation functions. 1970J. Schwinger Particles, Sources, & Fields iii. 145 Considering spin o particles and their real scalar sources,..we examine the effect of adding an additional weak source δK(x). It is given by δW(k) = ∫(dx)δK(x)ϕ(x), where ϕ(x) = ∫(dx′) × Δ + (x -x′)K(x′). This combination of source and propagation function, measuring the effect of pre-existing sources on a weak test source, is the field of the sources. 1977Grimsby Even. Tel. 31 May 9/5 A hundred small cannabis plants in propagation trays, plus smoking pipes and an LSD tablet were found. |