| 释义 |
stratified, ppl. a.|ˈstrætɪfaɪd|
[f. stratify v. + -ed1.]
1. Disposed in strata or layers.
a. Geol. Of rocks, a portion of the earth's crust.
1799[see polygenous a. 1]. 1802Playfair Illustr. Huttonian Theory 65 In the view now given of metallic veins they have been considered as traversing only the stratified parts of the globe. 1813Bakewell Introd. Geol. (1815) 29 Stratified mountains or rocks are those which are composed of layers of stone, laid over each other. 1832H. T. De la Beche Geol. Man. (ed. 2) 35 In the accompanying Table, rocks are first divided into Stratified and Unstratified. 1854H. Miller Sch. & Schm. xxi. (1860) 228 The deposit..consists..of alternate beds of limestone, sandstone and stratified clay. 1889Hardwicke's Sci.-Gossip XXV. 69 The absence of large erratic blocks in the stratified beds may indicate a period of extreme glaciation. 1897G. P. Merrill Rocks etc. 34 The term massive is applied to such igneous rocks as show no sign of bedding or stratification, while limestones, sandstones, and such other rocks as are arranged in more or less parallel layers are described as stratified.
b. in various applications; said, e.g., of incrustations, animal or vegetable tissues, a solid or fluid substance.
1809J. Kidd Min. I. 38 The calcareous incrustation..is of a stratified appearance. 1859Parkinson Optics (1866) 106 In this way the law of variation of density of a stratified medium may be expressed. 1887T. W. Shore Elem. Biol. Vegetable 13, 1. The thin common cell wall, or middle lamella. 2. The much thicker stratified thickening of the cell wall. 1897Allbutt's Syst. Med. III. 360 The internal surface [of the œsophagus] is covered with stratified squamous epithelium.
c. Electr. (Cf. stratification 2 d.)
1856Rep. Brit. Assoc. ii. 10 On the Stratified Appearance of the Electrical Discharge. By W. R. Grove. 1865Ibid. ii. 15 On the Change of Form and Colour which the Stratified Discharge assumes when a Varied Resistance is introduced in the Circuit of an Extended Series of the Voltaic Battery. 1873J. C. Maxwell Electr. & Magnetism I. 369 On Stratified Conductors. Let a conductor be composed of alternate strata of thickness c and c′ of two substances whose coefficients of conductivity are different.
d. Placed in alternate layers with something else.
1855J. Scoffern in Orr's Circ. Sci., Elem. Chem. 490 The stratified copper leaves..are taken out.
e. Of a lake or other body of water: exhibiting stratification. [tr. F. stratifié (F. A. Forel 1880, in Bibliothèque Univ.: Arch. des Sci. physiques et nat. IV. 94).]
1881Proc. Boston Soc. Nat. Hist. XXI. 66 In summer the return current takes place at no great depth, because then the water is stratified according to its temperature. 1910E. M. Wedderburn in Murray & Pullar Bathymetrical Surv. Sc. Fresh-Water Lochs I. 104 As winter draws on the lake becomes thermally stratified. 1957G. E. Hutchinson Treat. Limnol. I. v. 334 Not only can a lake oscillate as a whole, but if it is stratified, the various layers of different density can oscillate relative to one another. 1972M. G. Gross Oceanography xi. 301 Tidal currents [in an estuary] cause mixing between layers, so that the waters become only moderately stratified. 1980G. E. Fogg in Barnes & Mann Fund. Aquatic Ecosystem ii. 37 Sometimes lakes are permanently stratified, as for example in tropical regions.
f. Sociol. (Cf. stratification 2 e.)
1927P. Sorokin Social Mobility ii. 11 If the economic status of the members of a society is unequal, if among them there are both wealthy and poor, the society is economically stratified. 1960V. Packard Status Seekers xxii. 325 Life is said to be more stable and serene in clearly stratified societies. 1969C. D. Darlington Evol. of Man & Soc. xviii. 422 The urban society was still stratified and even more highly stratified, but the strata and their boundaries had changed.
g. stratified charge: in an internal-combustion engine, a rich mixture for ignition in each cycle followed by a lean one for combustion, usu. achieved by having a side chamber in each cylinder into which the mixture for ignition is introduced; freq. attrib.
1931D. R. Pye Internal Combustion Engine vi. 148 (caption) Thermal efficiencies obtainable at weak petrol-air mixtures with ‘stratified charge’ operation. 1953H. R. Ricardo High-Speed Internal Combustion Engine (ed. 4) xviii. 366 Two alternative schemes were tried:..(2) The use of a stratified charge in which the mixture immediately in the zone of the sparking-plug is very much richer than that in the main body of the combustion space. 1976National Observer (U.S.) 22 May 9/4 The Japanese car is..powered with a larger version of the stratified-charge engine. 1981Sci. Amer. May 45/1 Direct-injection stratified-charge engines have efficiency advantages comparable to those of the diesel.
2. Statistics. Employing, or obtained by means of, the technique of stratification.
1920A. L. Bowley Elements of Statistics (ed. 4) ii. iv. 333 In a non-stratified selection we should have had σ = ·0141. 1934Jrnl. R. Statistical Soc. XCVII. 567 This method has been called by Professor Bowley the method of stratified sampling. 1956B.B.C. Handbk. 1957 104 This Survey employs part-time interviewers..who each day question some four thousand people—a sample or cross-section of the adult public... (Technically speaking, the sample used is a stratified quota sample.) 1980Nature 1 May 5/3 One [technique] is stratified sampling, in which the site was first divided into 20 metre by 20 metre squares, and then four randomly selected one metre by one metre trenches excavated within each of the larger squares. |