| 释义 |
▪ I. plateau, n.1|pləˈtəʊ, ˈplætəʊ|
Pl. plateaux, -eaus |-əʊz|.
[a. F. plateau:—OF. platel (12th c.) flat piece of metal, wood, etc., dim. of plat: see plat a.]
1. a. Geog. An elevated tract of comparatively flat or level land; a table-land.
1796State Papers in Ann. Reg. 262/2 The summits, plateaux (flat tops of hills), mountains, and other places. 1807Ibid. 11 A rising ground or flattish hill, which, in the military phraseology of the French, is called a plateau. 1830Lyell Princ. Geol. I. 375 On the chalk of Berkshire, extensive plateaus, six or seven miles wide, would again be formed. 1834Pringle Afr. Sk. ix. 293 A sort of plateau or table-land, rising abruptly from the plains..in immense buttresses of naked rock. 1880Haughton Phys. Geog. iv. 168 The great Central tableland of Asia, culminating in the lofty plateau of Thibet. 1898Bullen Cruise of Cachalot 91 The grassy plateau on which the village stands.
b. transf. A level elevation in a sphygmographic tracing of the pulse; hence, the form of pulse which shows this. More widely, a more or less level portion of a graph adjacent to a lower sloping portion; a condition or period that can be so represented, when there is neither an increase nor a decrease in something.
1894W. Ewart Pulse-Sensations iv. xiii. 277 In the cardiogram..this point occurs in the line of descent—or else in the ‘plateau’. 1898Allbutt's Syst. Med. V. 470 In the systolic plateau two minor undulations of pressure are seen. Ibid. 934 This feature of the pulse and its long plateau would set aside that extremely rare affection pulmonary stenosis. 1943J. D. White in H. L. Mencken Amer. Lang. Suppl. I. (1945) 416 Plateaus are the thing now. War production is on a plateau, meaning that it is way up and has been up long enough to establish a plateau in the curve of production figures. 1948Manch. Guardian Weekly 30 Dec. 9 The men on the Stock Exchange modestly allow they will be content with ‘a plateau’. 1959Listener 1 Jan. 18/1 The Ionians..had already reached a high plateau of civilization. 1961Ann. Reg. 1960 474 Although industrial production in aggregate was seemingly on a plateau, the fortunes of particular industries showed marked variations. 1969H. Perkin Key Profession v. 208 The post-1947 decline in the birth-rate would be succeeded by a further upturn, rising to a higher and more permanent ‘plateau’ from about 1960 onwards. 1976Nature 8 July 83/2 The world total of annual military expenditure..has remained on a plateau of 210,000 million US dollars (at 1970 prices) for seven years now. Ibid. 146/1 Fig. 1b shows a large current with a plateau at around +0·8 V.
c. Psychol. A stage in learning when no apparent progress is made.
1897Bryan & Harter in Psychol. Rev. IV. 52 All agree that just below the ability to understand what is spoken, there is a long discouraging plateau where many give up [learning telegraphy] in despair. 1936Brit. Jrnl. Psychol. XXVI. 218 The occurrence of breathing-places and plateaux in the learning process has usually been attributed..to the gradual formation of low and high habits... A plateau means that the lower order habits are approaching their maximum development, but have not become sufficiently automatic to leave attention free to attack the higher order habits. 1964P. M. Fitts in A. W. Melton Categories of Human Learning 265 The present writer knows of no evidence contrary to Keller's (1958) conclusion that a true plateau in skill learning has not been demonstrated, and that when such effects occasionally are reported they are artifacts. 1972P. Bach-y-Rita Brain Mechanisms iv. 77 Acquisition of a predominantly perceptual skill..and acquisition of a motor skill..are remarkably similar processes. Each is slow, and has several plateaus.
d. Physics. The range of applied voltage over which the counting rate of a Geiger counter remains approximately the same, for a given intensity of radiation.
1937Physical Rev. LI. 1027/1 Reliable counting characteristics and long plateaus were obtainable only with counters whose cathode surfaces were completely cleaned..previous to filling. 1953H. H. Staub in E. Segrè Exper. Nucl. Physics I. i. iv. 149 A good counter shows a plateau of 160 volts over which the counting rate should not increase by more than 3 percent. 1973J. Yarwood Atomic & Nucl. Physics xiv. 396 Well designed counter tubes have a plateau slope of about 2 per cent. increase in count rate for an operating voltage increase of 100 V. This flat plateau is valuable since it means that the operating voltage is not critical.
e. The second of four recognized stages of sexual intercourse (see quot. 1960), in which there is an intense sexual excitement lasting a variable but usually short time following a longer phase of increasing excitement and succeeded either by orgasm or by a longer period of decreasing excitement. Usu. attrib., esp. in plateau phase.
1960W. H. Masters in Western Jrnl. Surg., Obstetr. & Gynecol. LXVIII. 58 The four phases of the human female's sexual response cycle are in order of their development: (1) the excitement phase; (2) the plateau phase; (3) the orgasmic phase; and (4) the resolution phase. Ibid., This plateau phase of sexual response is the base line from which the individual climbs with relative ease and rapidity to orgasm. 1966Masters & Johnson Human Sexual Response i. 7 Some physiologic reactions..may be confined to one particular phase of the cycle. Examples are the plateau-phase color changes of the minor labia in the female and the coronal engorgement of the penis in the male. 1972Encycl. Love & Sex i. 8/2 One of the most common of all sexual problems occurs when the man's plateau phase is short,..so that he reaches his climax too soon to satisfy his partner. 1974H. S. Kaplan New Sex Therapy i. 9 During plateau, the local vasocongestive response of the primary sex organ is at its peak in both genders. Ibid. 21 The retarded ejaculator becomes excited, reaches the plateau, may experience the intense urge to proceed to orgasm which is characteristic at this time, but cannot ejaculate despite vigorous and effective stimulation. 1976B. Goldstein Human Sexuality ix. 157 If sexual motivation is maintained by adequate erotic stimulation, the excitement phase accelerates to the plateau phase.
2. a. An ornamented tray or dish for table-service. b. A decorative plaque.
1791Washington Lett. Writ. 1892 XII. 53 The plateaux which you had the goodness to procure for me arrived safe. 1796Ld. Colchester Diary (1861) I. 34 The middle of the table was filled with a painted plateau ornamented with French white figures and vases of flowers. 1800in Spirit Pub. Jrnls. IV. 11 An elegant platteau, and a silver epergne. 1831J. Holland Manuf. Metal I. 136 The plateau sufficiently large to hold the entire tea equipage of a numerous party. 1861Times 6 June, The Grocers..have secured a lasting record of their commercial adventures in the shape of a gorgeous silver plateau, comprising four massive pieces, each representing a scene in the progress of a trading caravan through the Desert.
3. transf. A style of woman's hat with level top.
1900Daily News 21 July 6/5 Merely a burnt-straw plateau with a cluster of flowers under the raised brim at the left side. 1901Lady's Realm X. 650/1 Yet again have I seen the double plateau look perfectly charming in all-black.
4. attrib. and Comb., as (in sense 1) plateau air, plateau-ice, plateau land, plateau region, plateau state, plateau valley; plateau-like adj.; (in sense 1 b) plateau length, plateau level, plateau slope, plateau value; (in sense 3) plateau hat; plateau basalt, basaltic lava extruded from fissures and forming sheets that cover many square miles; in Petrol. freq. used with the implication of a tholeiitic or, formerly, an alkalic nature; plateau gravel, gravel occurring in a sheet on hilltops or a plateau, at a height that suggests it has been raised by earth movement since its deposition.
1888Proc. R. Soc. Edin. XV. 347 In Antrim bosses of trachyte and pitchstone rise through the *plateau⁓basalts. 1933Amer. Jrnl. Sci. CCXXV. 241 Olivine-Basalt Magma-Type... Many of the Patagonian plateau basalts appear to be of this type and some, at least, of the Siberian Traps. Ibid. 242 The Deccan Traps and the majority of the plateau basalts which have been studied are of tholeiitic composition. 1944A. Holmes Princ. Physical Geol. xx. 458 Plateau basalts covering areas of 200,000 square miles or more occur in the Columbia and Snake River region of the north-western United States. 1972G. A. Macdonald Volcanoes xi. 255 The basaltic lava flows that built the plains have commonly been called pleateau basalts. 1977A. Hallam Planet Earth 20/3 The materials of cratered plains [on the moon] resemble terrestrial plateau basalts.
1872Wood & Harmer in S. V. Wood Suppl. Monogr. Crag Mollusca p. xxvi. (heading) The *Plateau gravel. 1873J. Geikie Gt. Ice Age (1894) 559 The deposition of the plateau-gravels was succeeded by a long period of valley-erosion. 1881Proc. Geologists' Assoc. VI. 33 On the top of Crawley (Portesbury) Hill..the plateau-gravel, with its overlying loam (loess) and its ferruginous layers, is well seen in the railway-cutting. 1970R. J. Small Study of Landforms vii. 234 In the New Forest.., the Tertiary sands and clays are overlain at many points by thick plateau gravels of Quaternary age.
1856Kane Arct. Expl. I. xxv. 336 The surface of the *plateau-ice, the mer-de-glace of the island.
1897M. Kingsley W. Africa 638 The great park-like *plateau lands.
1965Wireless World Aug. 382/2 This is particularly useful for Geiger tubes, as they tend to have individual working points and sometimes, if aged, a limited *plateau length.
1957G. E. Hutchinson Treat. Limnol. I. xii. 744 The absolute concentration..fell rapidly, reaching a *plateau level which represents about 10 per cent of the original amount added.
1863M. Howitt F. Bremer's Greece I. i. 7 The Acropolis..is a rock, which, *plateau-like, rises directly from the plain.
1962Newnes Conc. Encycl. Nucl. Energy 296/1 A good counter is one which has a low *plateau slope, e.g. less than 5 per cent increase in count-rate for 100 V increase in applied voltage.
1964L. Wilets Theories Nucl. Fission i. 3 As a function of excitation energy, the probability of fission frequently assumes the form of a barrier transmission curve.., rising to some *plateau value.
5. Med. (Passing into adj.) Of the pulse: having a plateau (sense 1 b) in the rising portion of the sphygmomanometric tracing.
1923W. D. Reid Heart in Mod. Practice xviii. 231 If the pulse is anacrotic and plateau in type, the diagnosis [of aortic stenosis] obtains strong support. 1936S. A. Levine Clin. Heart Dis. iv. 77 The plateau form of radial pulse is fairly characteristic of aortic stenosis. Ibid., This will counteract the plateau character. 1972Passmore & Robson Compan. Med. Stud. III. xvi. 6/1 The plateau pulse..is due to the slow ejection of blood from the left ventricle through the narrowed orifice.
▪ II. plateau, v.|ˈplætəʊ, pləˈtəʊ|
[f. plateau n.1]
intr. To enter a period of stability or stagnation; to cease increasing or progressing, to level out. So ˈplateaued (or plaˈteaued) ppl. a.; ˈplateauing (or plaˈteauing) vbl. n.
1952Proc. Soc. Exper. Biol. & Med. LXXIX. 584/2 In each experiment 10 ‘plateaued’ female rats of the Long-Evans strain were used. 1966Electronics 3 Oct. 23 Many companies have diversified their activities or extended their product lines, after having been scared by the plateauing of business in 1962 and 1963. Ibid., U.S. electronic companies have bitten deeply into local markets, causing the sales of European firms to plateau or slide on their home grounds. 1967Economist 16 Sept. 1009/1 There is an ominous lull in military cargoes which the shipping companies believe is temporary but which the military expect to be permanent and which they describe as ‘the pipeline plateauing out’. 1969D. Clark Nobody's Perfect ii. 60 The hope that some graph will plateau higher up the scale. 1973Maclean's Mag. Aug. 63/1 Kids get into swimming and they have a lot of initial success and then they plateau—they stick at the same level for a long period, maybe six months. 1975Harvard Business Rev. LIII. 30/3 We found a large number of managers who, in the judgment of their organization, have ‘plateaued’. That is, there is little or no likelihood that they will be promoted. 1976New Scientist 26 Aug. 439/2 The counts from radioactive carbon dioxide rose rapidly and then plateaued. 1978Jrnl. R. Soc. Arts CXXVI. 483/2 Petroleum supply will peak or plateau at the end of the century. |