| 释义 |
saturation|sætjʊəˈreɪʃən|
[ad. late L. saturātiōn-em, n. of action f. L. saturāre to saturate. Cf. F. saturation.]
The action of saturating; the condition of being saturated.
†1. Complete satisfaction of appetite; satiation.
1554Coverdale Hope Faithful xxxi. 212 For tediousnesse and grefe runneth customably wyth saturacion or fulnesse. 1816–30Bentham Offic. Apt. Maximized, Extract Const. Code (1830) 16 For the perpetual saturation of appetites essentially unsaturable. 1831Carlyle Sart. Res. ii. ix, The Shoeblack..would require..for his permanent satisfaction and saturation, simply this allotment, no more, and no less. 1831Syd. Smith Wks. (1850) 565 The advocates of Boroughmongers must be crammed to saturation, before there is a morsel of bread for the man who does not sell his votes. 1832L. Hunt Transl. Poet. Wks. 243 When I have eat and drank—yea, ev'n to saturation.
2. The action of thoroughly soaking with fluid; the condition of being thoroughly soaked.
1846J. Baxter Libr. Pract. Agric. (ed. 4) II. 358 That the saturation of any vegetable fibre or compost with liquid manure or urine is of great use to the crop. 1882Vines tr. Sach's Bot. 814 In one case the amount of water present in the soil was 10 per cent...of the amount requisite for complete saturation. 1897M. Kingsley W. Africa 555, I am wet through, but it is not uncomfortable at this temperature,..if you can..forget the risk of fever which saturation entails.
3. a. The action of charging, or the state of being charged, up to the limit of capacity; spec. in Chem. the condition of a substance when combined with or holding in solution the largest proportion of another substance that it can take (cf. unsaturation.); in Physics, the condition of holding as much suspended matter, or of being as highly charged with electricity, heat, etc. as possible. (See saturate v.) point of saturation: the degree of charge at which a substance becomes saturated. More widely in Physics, a condition or phenomenon in which a quantity (usu. the value of some property) no longer increases in response to an increase in the magnitude of some external influence, or ceases to alter in the usual way; spec. in Spectroscopy (see quot. 1976). See also senses 3 c, d, f following.
1659H. More Immort. Soul i. ii. 13 To both these may be applied the termes of Reduplication and Saturation. 1673Phil. Trans. VIII. 5190 And this injection of calcin'd Tartar must be continued, untill all Fermentation do cease, that is, to the very degree of Saturation. 1758Reid tr. Macquer's Chym. I. 20 The instant when such proportions of the two saline substances are mixed together, that the one is incorporated with as much of the other as it can possibly take up, is called the Point of Saturation. 1799Sir H. Davy in Beddoes Contrib. Phys. & Med. Knowl. 34 Since the word gas..is intended to express the chemical combination or rather the saturation of bodies with caloric. 1807T. Thomson Chem. (ed. 3) II. 99 This augmentation varies with the quantity of salt dissolved. In general, it is the greater the nearer the solution approaches to saturation. 1848tr. Regnault in Chem. Rep. & Mem. (Cavendish Soc.) 293 The law regulating the densities of aqueous vapour in a state of saturation or non⁓saturation, at different pressures and different temperatures. 1857Miller Elem. Chem. (1862) III. 231 It then produces a base..which requires two atoms of a monobasic acid for its saturation. 1860Tyndall Glac. i. xxiv. 174 An atmosphere charged to saturation with aqueous vapour. 1866Notices Proc. R. Inst. Gt. Brit. IV. 422 The saturation of these two units [of attraction] by the trivalent nitrogen atom. 1882Geikie Text Bk. Geol. iii. ii. ii. §1. 328 This vapour remains invisible until the air containing it is cooled down below its dew-point, or point of saturation. 1902J. B. Cohen Theoret. Org. Chem. xvii. 240 The saturation of one unsaturated carbon atom necessitates that of the other. 1948Physical Rev. LXXIII. 683/1 As H1 is increased, the thermal contact between spin system and lattice eventually proves unable to cope with the energy absorbed by the spin system, the spin temperature rises, and the relative absorption..diminishes. It is the onset of this saturation effect which has been used to measure the spin-lattice relaxation time. 1953Ibid. XCI. 206/2 From the saturation of the absorption and a measurement of the rf field, a spin-lattice relaxation time of approximately one millisecond is calculated. 1959G. Troup Masers iii. 37 If the energy density of radiation falling on an assembly of molecules having an excess upper state population is increased, there comes a time when the energy of induced emission is no longer linearly dependent on the incident radiation energy density. This phenomenon is known as saturation. 1961G. R. Choppin Exper. Nuclear Chem. v. 62 The higher the atomic number of the scattering material, the larger is fb [back-scattering factor]. Also, fb increases with thickness up to a saturation thickness beyond which it is a constant. 1964N. G. Clark Mod. Org. Chem. vi. 89 By partial saturation of this triple bond with hydrogen, an olefin is produced. 1968A. A. Baker Unsaturation in Org. Chem. vi. 71 His formulas..illustrate the progressive saturation of a diatomic carbon molecule to acetylene, to ethylene, and to completely saturated ethane. 1972McFarlane & White Techniques of High Resolution N.M.R. Spectroscopy v. 55 The gross observable effects of saturation are a general broadening of the spectrum with associated loss of peak height and resolution. 1976D. Shaw Fourier Transform N.M.R. Spectroscopy ii. 20 Saturation is the equalisation of the population in the ground and the excited state which occurs because relaxation from the excited state is slow and with a strong exciting field a dynamic equilibrium can be set up. In this equilibrium the number of nuclei in the upper and lower states become [sic] equal, and the signal saturates, or disappears.
b. transf. and fig.
1820T. G. Wainewright Ess. & Crit. (1880) 55 Corregio's mind must have been full to saturation, of the honey-dew of Christianity, when he gave birth to this mysterious conception. 1848H. Miller First Impr. viii. (1857) 128 A long series of historic events had served..to fill with it to saturation every recess of the popular mind. 1859Smiles Self-Help x. (1860) 265 Abernethy was of opinion that there was a point of saturation in his own mind, and that if he took into it something more than it could hold, it only had the effect of pushing something else out.
c. Magnetism. The condition of being as strongly magnetized as possible, or so strongly magnetized that an increase in magnetizing force produces no appreciable increase in magnetization.
1837Brewster Magnet. 134 It was magnetized to saturation. 1864Chamb. Encycl. VI. 262/2 Magnets, when freshly magnetised, are sometimes more powerful than they afterwards become. In that case, they gradually fall off in strength, till they reach a point at which their strength remains constant. This is called the point of saturation. 1920Whittaker's Electr. Engineer's Pocket-bk. (ed. 4) 144 In addition to the limitations imposed by saturation, the parts of the magnetic circuit where the flux is continually changing in value are further restricted by losses due to eddy-currents and hysteresis. 1962Newnes Conc. Encycl. Electr. Engin. 463/2 The coercivity is the magnetizing force necessary to remove the magnetism completely from a specimen which has been magnetized to saturation. 1974Encycl. Brit. Macropædia XI. 333/2 It was suggested in 1907 that a ferromagnetic material is composed of a large number of small volumes called domains, each of which is magnetized to saturation.
d. Electronics. The condition in which increase in the potential difference between two electrodes in a gas-filled or evacuated vessel leads to no increase in the current flowing between them, owing to the limitations of the gas as a current-carrier or the electrode as an electron-emitter.
1896Phil. Mag. XLII. 394 It is evident that this saturation must occur if the current destroys the conducting power of the gas. 1899Ibid. XLVII. 158 The great difficulty in producing complete saturation, i.e. to reach a stage when all the ions produced reach the electrodes, may be due to one or more of three causes. 1947R. Lee Electronic Transformers & Circuits v. 116 In plate-modulated class C amplifiers, sufficient excitation must be applied so that grid saturation still obtains at 100 per cent modulation; otherwise output would not be proportional to plate voltage. 1962D. F. Shaw Introd. Electronics x. 192 Other cathode materials, such as metallic oxides, do not exhibit full saturation.
e. Psychol. A term used in mental testing based on the theory of two-factor analysis put forward by C. S. Spearman (1863–1945) for the degree to which the general factor (g) saturates the specific factor or ability in question; also attrib.
1904C. S. Spearman in Amer. Jrnl. Psychol. XV. 276 Intellective saturation, or extent to which the considered faculty is functionally identical with General Intelligence. Ibid. 277 Mathematics, for example, has a saturation of 74 and Common Sense has one of about 96. 1927Psychol. Bull. XXIV. 392 Slocombe..applies the intellective saturation formula of Spearman to nine group tests. 1940C. L. Burt Factors of Mind xii. 299 Let us suppose that both the variances for the different factors and the saturation coefficients for the different tests are everywhere equal. 1951R. H. Thouless Gen. & Social Psychol. (ed. 3) xxiii. 367 This degree of dependence on the general factor was called by Spearman the saturation with g of the ability in question; the term more commonly used at the present time is the general factor loading.
f. Electronics. The state of operation of a transistor in which the collector current becomes independent of the base voltage, arising when the base-collector junction becomes forward-biased.
1956J. C. Logue in L. P. Hunter Handbk. of Semi-conductor Electronics xv. 48 In pulse-type computer systems, the length of time that the transistor is driven into saturation is controllable. 1962Simpson & Richards Physical Princ. Junction Transistors xvi. 389 ‘External’ control causes the ‘on’ position to be largely independent of transistor parameters..and makes heavy base overdrive possible without danger of saturation. 1975D. G. Fink Electronics Engineers' Handbk. xvi. 13 When the collector current IC reaches its maximum possible value.., saturation occurs and the collector junction becomes forward-biased.
g. The retention by the blood of the greatest amount of inert gas possible under the given pressure, as during a saturation dive (see sense 5 below); also transf., a saturation dive.
1971J. K. Summitt et al. in C. J. Lambertsen Underwater Physiol. 519 A study of five trained men during compression to a simulated depth of 1000 FSW, during subsequent saturation at this pressure for 77 hr and 30 min, and during decompression. 1974Encycl. Brit. Macropædia X. 926/1 Reasonably safe and efficient decompression from saturation at depths up to 600 feet..can be accomplished by a decompression at the rate of 15 minutes per foot.., or about 100 feet..per day. 1975BP Shield Internat. May 5/1 In excess of 14,000 diver man hours were spent in saturation without a single decompression problem or lost time accident. 1975Offshore Engineer Dec. 7/2 A 17-day saturation involving six divers at depths of up to 260m carried out by Strongwork Diving (International) has given a British company a new record.
4. a. Chromatics. Degree of intensity (of a colour); relative freedom from admixture of white. Cf. hue n.1 3 c.
1878Encycl. Brit. VIII. 824/1 Saturation, which depends on the amount of white the colour contains; thus, it is saturated when there is no white, as in the pure colours of the spectrum, and there may be an infinite number of degrees of saturation from the pure colour to white. 1879O. N. Rood Mod. Chromatics iii. 39 Purity and luminosity are the factors on which the intensity or saturation depends. 1966[see hue n.1 3 c]. 1967E. Short Embroidery & Fabric Collage i. 12 The hues are all used at their full strength or saturation, i.e. they are not diluted in any way by black or white. 1970Nature 19 Sept. 1183/1 Discrimination tests revealed that sorters identified stamps most easily if seven colours were used each at two distinct levels of saturation, for example, dark blue and light blue, dark green and light green. 1978Sci. Amer. Mar. 87/3 The color pictures were generated by first determining the spectral irradiance of Mars in each of the regions and then computing the hue, brightness and saturation of color for the range of wavelengths to which the human eye is sensitive.
b. transf. The name of a control on a colour television set used to adjust the quality of colours in the picture.
1964M. S. Kiver Color Television Fundamentals (ed. 2) v. 144 There is also a color saturation control to adjust the vividness or depth of color. 1967Punch 12 Apr. 532/3 It is good to be able to report that the colour sets shown at the Ideal Home Exhibition in London..had one colour control only. For reasons impossible to conjecture it is labelled ‘Saturation’. Twisting this knob does not release a jet of water, however; it simply changes the picture from black-and-white to any strength of colour desired. 1968Guardian 5 July 8/5 There is a secondary colour knob marked either ‘saturation’ or ‘colour’ which enables you to control the shade you receive. 1974A. G. Priestly Receiving PAL Colour Television v. 103 A good saturation control is not easy to design. The control itself is usually situated on the front of the receiver for use by the viewer.
5. attrib. and Comb., as saturation charge, saturation experiment, saturation recording, saturation time, saturation weapon; saturation current, the greatest current that can be carried by a gas or electronic device (cf. senses 3 d, f above); saturation dive, a dive made with the diver's blood-stream saturated with an inert gas, usu. helium or nitrogen, at the pressure of the surrounding water, so that the time required for decompression afterwards is independent of how long the dive lasts; so saturation diver, diving vbl. n.; saturation point, the state or condition at which saturation begins; the limit of acceptance; freq. fig.; saturation (vapour) pressure Physics (see quot. 1969).
1969*Saturation charge [see saturation time below].
1896Phil. Mag. XLII. 403 The *saturation current depends only on the number of conducting particles produced by the rays. 1929B.B.C. Year-bk. 1930 450/2 As the anode voltage applied to a three-electrode valve is increased, the anode current also increases up to a point, when a further increase in anode voltage does not increase the anode current. This maximum value of the current is called the ‘saturation current’. 1954L. M. Krugman Fund. Transistors iii. 43 The saturation current is composed of two components. The first is formed by thermally generated carriers which diffuse into the junction region. The second component is an ohmic characteristic which is caused by surface leakage across the space charge region. 1976Millman & Halkias Electronic Fund. & Appl. iv. 79 In addition to the variability of reverse saturation current with temperature, there is also a wide variability of reverse current among samples of a given transistor type.
1966Sci. Amer. Mar. 27/1 It is clear..that the ‘partial pressure’ of oxygen should be kept between about 150 and 400 millimeters of mercury during the at-depth phase of a long *saturation dive. 1974Daily Tel. 22 Feb. 7/6 The record saturation dive in the North Sea was 621ft. The diver took a day to get down, and after surfacing spent 3½ days in a decompression chamber.
1970Sci. Jrnl. Feb. 15 The Argyronète, a self-propelled submersible combining a house in which *saturation divers can live (under sea bottom pressure) and a conventional submarine with a crew at normal atmospheric pressure. 1974Encycl. Brit. Macropædia X. 926/1 In practice, saturation divers are compressed slowly to working pressure, generally in the deck chamber, and are then transferred as needed to and from the work site sealed in the diving bell. 1975BP Shield Internat. May 5/4 It is..not uncommon for saturation divers to spend from two to three weeks under saturation conditions.
1966Sci. Amer. Mar. 27/1 Although this ‘*saturation diving’ is efficient, it imposes an extra technical burden, because the schedules for the ultimate decompression must be calculated and controlled with particular care. 1970New Scientist 26 Mar. 617/2 The experiment successfully demonstrated the feasibility in scientific research of saturation diving—a technique which relies on the fact that once the body tissues become saturated with gases breathed under pressure, the time to remove them during decompression remains the same no matter how much longer the person stays at that pressure. 1974Daily Tel. 22 Feb. 7/6 Bone necrosis is a growing fear connected with saturation diving. 1976Offshore Platforms & Pipelining 122/3 Any diving inspection beyond the 140-ft. depth, which requires any appreciable time on the bottom, is carried out by using saturation diving.
1904Brit. Med. Jrnl. 10 Sept. 563 By *saturation experiments we can remove the one opsonine after the other.
1858O. W. Holmes Aut. Breakf.-t. v. 52 The *saturation-point of each mind differs from that of every other. 1902Encycl. Brit. XXXIII. 631/2 It is a fair inference that similar behaviour would be observed up to the saturation-point if surface condensation could be avoided. 1927Sunday Times 13 Feb. 2 Those controlling the industry realize that the world production of motor-cars has by no means reached saturation point. 1932Wodehouse Louder & Funnier 71, I rather fancy that sinister jewel-trackers have about reached saturation-point. 1977Times 30 Apr. 3/3 The popularity of the forest may have reached saturation point.
1884A. Daniell Princ. Physics xiii. 346 Each volatile liquid has its own *saturation pressure for each temperature. 1902Encycl. Brit. XXXIII. 631/1 The values of the saturation-pressure have been very accurately determined for the majority of stable substances.
1975D. G. Fink Electronics Engineers' Handbk. xxiii. 56 There are two methods of recording called saturation and nonsaturation. With *saturation recording, material under the head is fully saturated throughout the material thickness.
1969J. J. Sparkes Transistor Switching i. 23 The turn-off time is divided into two parts. First the *saturation time,..during which the saturation charge..is used up and the collector current does not significantly change. Second, the fall time.
1955Sci. Amer. Mar. 74/2 For every temperature there is a ‘*saturation vapor pressure’ at which the rates of escape and of deposit at a step balance. Under these conditions the crystal does not grow. It can grow only when the vapor is supersaturated. 1969Gloss. Terms Vacuum Technol. (B.S.I.) I. 9 Saturation vapour pressure, the pressure exerted by a vapour when in equilibrium with its solid or liquid phase.
1955Bull. Atomic Sci. Jan. 14/3 The construction of ‘*saturation weapons’ became possible when it was discovered that under certain circumstances a tiny amount of matter transforms into a tremendous amount of energy.
b. Designating an activity intended to achieve the complete saturation of its object; orig. Mil., referring to intensive bombing operations, esp. in saturation bombing; hence saturation bomb vb.; more widely, applied to an intensive operation in the fields of marketing, advertising, security, and the like.
1942Sun (Baltimore) 15 Oct. 13/5 The fact that only nine bombers were lost..was taken to mean that the ‘saturation technique’ was used to crowd so many planes over the area in a short raid that the strong defenses..were swamped. 1943Time 7 June 29/3 According to U.S. testimony, the precision bombing of the American forces is more effective, ton for ton, than the saturation bombing of the R.A.F. Ibid. 30 Aug. 33/2 The greatest air force the world has known: a combination of the daylight precision bombing planes of the U.S. Eighth Air Force and the heavy night⁓time saturation raiders of the R.A.F. Ibid. 6 Sept. 36/3 Of the 73 raids Berlin had experienced, this was the worst, the first of the kind of saturation raids that had wrecked Hamburg. 1944Times 28 Mar. 4/5 A great weight of high-explosives and incendiaries pounded Essen in a ‘saturation’ attack which lasted just under half an hour. 1957Clark & Gottfried Dict. Business & Finance 314/2 Saturation selling involves making a product available in every outlet in an area, and using every possible means of sales promotion. 1958Listener 5 June 950/3 Mrs. Ancsa's father had been killed in a saturation air-raid. 1962Economist 2 June 920/3 The large number of copies of each film necessary for this so-called ‘saturation release’. 1966Times 12 July 11/3 It is simply not true to say that America has engaged in saturation bombing. 1971Wall St. Jrnl. 13 Aug. 14/1 He came to realize such journalism is possible through ‘saturation reporting’. 1975R. H. Rimmer Premar Experiments (1976) i. 19 The days when we believed we could change things—like the draft, or the saturation bombing of Vietnam, or the Pentagon running the universities. 1977Time 28 Nov. 29/2 As the deadline arrived.., West Germany's national airline responded with a policy of saturation security for its 411 daily scheduled flights worldwide. 1979P. Niesewand Member of Club xxi. 165 The Cubans were saturation bombing the camp. 1981I. A. Gordon in N.Z. Listener 18–24 Apr., The big idea behind the saturation-bombing of consumers with a trade-name is to persuade you that X (and not Y or Z) is the brand to remember. |