| 释义 |
polar, a. (n.)|ˈpəʊlə(r)|
[ad. med.L. polār-is, f. L. pol-us pole n.2: see -ar1. Cf. It. polare (c 1300 in Dante), Sp. polar, F. polaire (1556 in Hatz.-Darm.).]
A. adj.
1. Astron. and Geog. Of or pertaining to the poles of the celestial sphere or of the earth; situated near or connected with either pole. Also, of or pertaining to the poles of another heavenly body.
1551Recorde Cast. Knowl. (1556) 41 Recken from one of the poles..23 degrees and an halfe,..draw a circle of that circuit about eche Pole... These circles maye well bee called Pole circles, or Polar circles. 1594J. Davis Seaman's Secr. ii. (1607) 6 The Artick Polar circle is one of the lesser circles, deuiding the Sphere into two vnequall partes. 1667Milton P.L. x. 289 As when two Polar Winds..together drive Mountains of Ice. 1669Sturmy Mariner's Mag. vii. ii. 5, [I] call it a Polar Plane, because the Poles thereof are in the Poles of the World. a1711Ken Hymnotheo Poet. Wks. 1721 III. 120 Devotion cold as Polar Ice was grown. 1815J. Smith Panorama Sc. & Art I. 277 The polar diameter of the earth. 1856Kane Arct. Expl. I. xxiii. 302 Well known to the Polar traveller. 1878Huxley Physiogr. 178 The cold polar waters sink by their density. 1894[see polar cap in 1 b below]. 1922H. S. Jones Gen. Astron. v. 134 The structure of the corona is very complex; it has no definite boundary and is usually symmetrical with respect neither to the centre of the Sun nor to the Sun's polar axis. 1973[see polar wandering in 1 b below].
b. In specific combinations with ns.: polar anæmia, anæmia due to residence in the polar regions during the sunless winter. polar bear, the white bear of Arctic regions, Ursus (or Thalarctos) maritimus, or its fur; also attrib., comb., and fig. polar cap, a large region of ice or other frozen matter surrounding a pole of a planet. polar circle, each of the circles parallel to the equator at the distance of 23° 28′ from either pole, bounding the Arctic and Antarctic zones. polar dial, a dial having its gnomon in the plane of the earth's axis. polar distance, the angular distance of any point on a sphere from the nearer pole; the complement of declination or latitude. polar flattening, the extent to which the polar diameter of a planet is shorter than the mean equatorial diameter. polar front (Meteorol.), a front between polar and equatorial air masses. polar hare, the white hare, Lepus arcticus; also called the Arctic hare. polar lights, the aurora borealis or australis. polar orbit, an orbit that passes over polar regions. spec. one whose plane contains the polar axis; so polar-orbiting adj. polar plant, a name for Silphium laciniatum, from the fact of its leaves pointing due North and South (Syd. Soc. Lex.). polar projection: see projection. polar star (mod.L. stella polaris siue Polus, in Alphonsine Tables, Venice 1518), the pole-star; also fig. = guiding star, guide, cynosure. polar wandering, the slow, erratic movement of the earth's poles relative to the continents which is thought to have occurred throughout geological time and is ascribed largely to continental drift; also extended to corresponding movement on other planets.
1781T. Pennant Hist. Quadrupeds II. 290 The *Polar bear might have been one [sc. an animal natural to a rigorous climate]. 1829[see sea-bear 3]. 1834Dickens Sk. Boz (1836) 1st Ser. I. 210 In their shaggy white coats they look just like Polar bears. 1847T. Arnold Let. 23 Oct. in N.Z. Lett. (1966) 10 In Prince Edward's Island, the winter..is enough to deter anyone but a polar bear. 1910E. T. Seton Life-Histories Northern Animals II. 1034 It [sc. the grizzly bear] is easily distinguished..from the Polar-bear by the latter's white colour. 1917R. Fry Let. 2 Mar. (1972) II. 404 Lady Scott, the widow of the Antarctic man came in yesterday with Peter Scott, the most wonderful little monster of a polar bear cub. 1959G. D. Painter Proust I. ix. 126 Montesquiou..had a room decorated as a snow-scene, with a polar-bear rug. 1968A. Diment Bang Bang Birds iii. 37 The living room, with its nylon polar bearskin rug. 1974P. Dickinson Poison Oracle i. 17 The polar bear was swimming, huge in its tiny pool. 1976H. L. Gunderson Mammalogy xvi. 375 The female and sometimes the male polar bears..become dormant throughout the winter.
1894Astron. & Astrophysics XIII. 542 So much for the terrestrial conditions under which the observations were made. The Martian ones were such as to make the *polar cap and its accompanying phenomena the centre of interest upon the planet. 1932[see fast ice s.v. fast a. 11]. 1967K. Lassen in B. M. McCormac Aurora & Airglow v. 453 We define the Polar Cap as the area with corrected geomagnetic latitude..greater than some 70°. 1968S. Glasstone Bk. of Mars vi. 107 Even if the polar caps are largely carbon dioxide, it does not mean that they do not also contain some solidified water.
1551–94*Polar circle [see 1].
1704J. Harris Lex. Techn. I, *Polar Dyals, are those whose Planes are parallel to some Great Circle that passes thro' the Poles, or parallel to some one of the Hours.
1816Playfair Nat. Phil. II. 35 From the azimuth, the *polar distance and the complement of latitude, compute the altitude. 1868Lockyer Elem. Astron. §329. 146 Sometimes the distance from the north celestial pole is given instead of that from the celestial equator. This is called north-polar distance.
1895Astrophysical Jrnl. II. 136 Micrometric measures of the diameters of Mars..give as the most probable value for the equatorial diameter of the planet at distance unity: 9{pp} .40 {pm} ·007; for the polar one: 9{pp} .35 {pm} ·005; and for the *polar flattening 1/190 of the equatorial diameter. 1899G. W. Myers tr. Lommel's Exper. Physics i. 85 From the values of the acceleration resulting from pendulum experiments and the magnitude of the centrifugal force, the polar flattening may be computed. 1966McGraw-Hill Encycl. Sci. & Technol. XIII. 516/2 Clairaut's formula for polar flattening... α = 5/2m - β in which m is the ratio of centrifugal force to gravity at the equator..and β is the coefficient of the principal latitude term.
1920V. Bjerknes in Nature 24 June 524/1 This line shows how far the cold air has succeeded in penetrating; it is a kind of *polar front line. Ibid. 524/2 All meteorological events of the temperate zone..are derived from the general atmospheric circulation..as we know it from the polar front. 1935C. F. Brooks et al. Why the Weather? (ed. 2) v. 50 The polar front is the forward edge of a moving mass of cold dry air, usually coming more or less directly from polar or sub⁓polar regions. 1973R. G. & A. H. Perry Synoptic Climatol. iii. 184 The classical view of tropical and polar air, separated by the polar front, does not accord well with modern knowledge of the general circulation.
1823J. Franklin Narr. Journey to Shores of Polar Sea 664 The *Polar hare appears to vary much in size, and consequently in weight. 1866W. R. King Sportsman & Naturalist in Canada 26 In this respect it differs from the Polar-hare, the finer and softer fur of which is in winter pure white to the roots. 1895[see blue hare (blue a. 12 a)]. 1911E. T. Seton Arctic Prairies 231 It was only a Polar Hare, the second we had seen.
1961Times Rev. Industry Feb. 26/3 There are a number of possible satellite systems using *polar, inclined and equatorial orbits. 1966McGraw-Hill Yearbk. Sci. & Technol. 171/1 NASA is presently planning six or seven observatories to be launched alternately into the highly eccentric equatorial orbits..and the low polar orbits. 1978Times 28 July 16/1 Europe's first lunar mission..would put a satellite in polar orbit round the moon.
1964Yearbk. Astron. 1965 141 Transmissions from the United States were being sent by conventional means to Jodrell Bank for reflection to Gorky via the *polar-orbiting balloon-satellite. 1968New Scientist 24 Oct. 175/3 It should now be possible, by means of a polar-orbiting satellite, to reap..data on.. cloud heights.
1851Mayne Reid Scalp Hunt. xxxv, We were traversing the region of the ‘*polar plant’, the planes of whose leaves, at almost every step, pointed out our meridian. 1885Girl's Own Paper Jan. 171/1 The Compass plant—variously known, also, as the pilot weed, polar plant, and turpentine weed.
1727–41Chambers Cycl., Pole Star, or *Polar Star. 1768–74Tucker Lt. Nat. (1834) II. 366 If we lose sight of our polar star, we shall quickly wander into inextricable difficulties. 1797Mrs. Radcliffe Italian i, Guided over the deep waters only by the polar star. 1854Moseley Astron. iii. 14. 1860 Reade Cloister & H. lxv, His pure and unrivalled love for Margaret had been his polar star.
1924J. G. A. Skerl tr. A. Wegener's Origin Continents & Oceans viii. 123 Extensive, even if slow, *polar wanderings are then able to take place. 1969Times 23 Apr. 7/4 Some of the more strange implications of the early studies of magnetism in ancient rocks—polar wandering, continental drift and the like. 1973Science 9 Mar. 997 Polar wandering during the past 108 years may be recorded by unique quasi⁓circular structures in the polar regions of Mars.
2. Magn. Disposing itself in the direction of the poles of the earth; having polarity; of or pertaining to a magnetic pole or poles (see pole n.2 5); magnetic.
1692Sir T. P. Blount Ess. 88 The Polar Vertue of the Loadstone was unknown to the Ancients. a1696Scarburgh Euclid (1705) 2 In Loadstones it is commonly known that there are Polar Points, called North and South. 1849Noad Electricity (ed. 3) 296 The pole N, of the magnet..acts favourably in inducing south polar magnetism in n, and north polar at S. 1860Tyndall Glaciers i. xx. 142, I examined the stones..and found them strongly polar. 1872Sir W. Thomson Reprint Papers 421 A polar magnet, as I shall henceforth call anything magnetized after the manner of a loadstone or a steel magnet. 1891S. P. Thompson Electromagnet 39 The pole or polar region of a magnet is simply that part of the surface of a magnet whence the internal magnetic lines emerge into the air.
3. a. Electr. Pertaining to the poles of a voltaic battery; having positive and negative electricity.
1836–41Brande Chem. (ed. 5) 320 The decomposition was perfectly polar, and decidedly dependent upon a current of electricity passing from the zinc through the acid to the platinum in the vessel c, and back from the platinum through the iodic solution to the zinc at the paper x. 1850Daubeny Atom. The. x. (ed. 2) 352 Rendering the substances..positive and negative, or, to adopt the explanation of Faraday, causing a polar state in their particles. 1893Sloane Stand. Electr. Dict. 454 Polar Region. In electro⁓therapeutics the area or region of the body near the therapeutic electrode.
b. Chem. Applied variously in cases where bonding electrons are unequally shared between atoms in a molecule, so that there is some separation of electric charge: (i) applied spec. to electrovalent or ionic bonds, and to substances (usu. solids) in which bonding of this type predominates; (ii) applied to covalent bonds in which electrons are unequally shared between the atoms, to molecules or groups which contain such bonds, esp. those which possess a resulting electric dipole moment, and to substances (usu. liquids) which consist of such molecules.
1913Jrnl. Amer. Chem. Soc. XXXV. 1443 In the preceding paragraphs we have suggested that there are two distinct types of union between atoms: polar, in which an electron has passed from one atom to the other, and non⁓polar, in which there is no motion of an electron. 1924O. Maass in H. S. Taylor Treat. Physical Chem. I. iv. 130 A polar molecule, one in which the molecular force of attraction is more concentrated in one particular part, so that if these molecules [of propionic acid] are oblong in shape, the field of force around one end, the {b1}COOH end, will be more pronounced. 1927N. V. Sidgwick Electronic Theory Valency iv. 52 Polar or ionizable linkages between the oppositely charged ions of a salt. 1950S. Glasstone Elem. Physical Chem. iii. 69 Compounds containing the groups {b1}OH, {b1}CN, {b1}COOH and {b1} NO2, which are examples of polar groups, are generally highly polar in character, unless they happen to be completely symmetrical. Ibid., Polar liquids have relatively high boiling points. 1950W. J. Moore Physical Chem. xi. 289 The polar compounds, of which NaCl was a prime example, could be adequately explained as being composed of positive and negative ions held together by coulombic attraction. 1951I. L. Finar Org. Chem. ii. 14 A symmetrical molecule is non-polar, although it may contain polar bonds. 1962Corson & Lorrain Introd. Electromagn. Fields iii. 82 A water molecule..possesses just such a permanent dipole moment and is thus called a polar molecule. 1966Gucker & Seifert Physical Chem. (1967) xi. 276 Both the Trouton and Hildebrand constants are abnormally high for many liquids like water and ammonia, which are known to be polar. 1970S. W. Benson Atoms, Molecules, & Chem. Reactions iv. 109 An extreme example of polar bonds occurs in the case of the alkali metal halides. 1974J. S. Blakemore Solid State Physics (ed. 2) iv. 338 Optical phonon scattering..is especially important for a solid with a polar (partially or completely ionic) lattice. 1975Hughes & Pooley Real Solids & Radiation ii. 15 Crystalline solids which are held together by electrostatic forces between oppositely charged ions are known as ionic or polar crystals.
4. Physics.
a. Of forces: Acting in two opposite directions. (Also in figurative applications.)
1809–10Coleridge Friend (1865) 55 There is, strictly speaking, no proper opposition but between the two polar forces of one and the same power. 1862Grove Corr. Phys. Forces (ed. 4) 38 Cases where a dual or polar character of force is manifested. 1863E. V. Neale Anal. Th. & Nat. 45 The thought of centres of force becomes that of polar force, where the most entire union is produced by the most complete opposition.
b. Of molecules: Regularly or symmetrically arranged in a definite direction (as though under the action of a magnetic force, e.g. like iron filings under the influence of a magnet).
1850Grove Corr. Phys. Forces (ed. 2) 36 At the point of maximum density the molecules of these bodies assume a polar or crystalline condition. 1862Ibid. (ed. 4) 39 In the rupture of crystals, we are dealing with substances having a polar arrangement of particles—the surfaces of the fragments cannot be assumed to be molecularly identical. 1870H. Spencer Princ. Psychol. (ed. 2) I. v. ii. 517 Adjacent molecules will be unsymmetrically placed..they will not stand in polar order.
5. Biol. Of or pertaining to the poles of a nerve-cell, an ovum, etc. See pole n.2 7. polar body, one of the small cells which bud off from an oocyte at the two meiotic divisions and do not develop into ova; = polocyte. Cf. oocyte, ootid.
1878Bell Gegenbaur's Comp. Anat. 111 The polar areas, which are surrounded by short fringe-like processes. 1882Vines Sachs' Bot. 581 In some instances the two polar nuclei meet, not in the centre, but towards the upper end of the embryo-sac. 1888Rolleston & Jackson Anim. Life Introd. 22 note, A clear spot, the polar spot or corpuscle, may appear at each pole of the spindle. Ibid. 23 As soon as the ovum has attained its definitive size, it very generally..gives origin to two polar bodies, or globules, or directive vesicles. 1898J. Hutchinson in Arch. Surg. IX. No. 36. 356 Opacities in the vitreous and posterior polar cataract had made their appearance. 1908[see ootid]. 1927Haldane & Huxley Animal Biol. ii. 60 In order to retain the large size of the egg, three of every four gametes produced are minute and non-functional, and are called polar bodies, while only one becomes a functional ovum. 1945,1946[see oocyte]. 1964[see ootid]. 1974Sci. Amer. Sept. 54/3 The remaining 23 [human chromosomes] replicate once more, and it is only after a sperm makes contact with the surface of the egg that a second polar body is expelled.
6. Geom. Relating or referred to a pole (see pole n.2 8); spec. Reciprocal to a pole; of the nature of a polar (see B.). polar co-ordinates: see co-ordinate B. 2. polar curve with respect to a line, the locus in tangential co-ordinates corresponding to the polar curve with respect to a point in polar co-ordinates. polar diagram, a diagram in which the length of the radius joining a fixed point to any point of a curve represents the magnitude of something (as the sensitivity of an aerial or the brightness of a lamp) measured in the direction of the radius. polar equation, an equation in polar co-ordinates. polar surface, in geometry of three dimensions, a locus analogous in all respects to a polar curve in plane geometry. polar vector (see vector).
1816tr. Lacroix's Diff. & Int. Calculus 129 The variables in this equation are what Geometers have called polar co-ordinates. 1831Hind Diff. Calc. 262 If r be the radius vector of a polar curve, and θ be the angle which it makes with a fixed axis. 1848G. Salmon Conic Sect. (1855) i. §44 To find the polar equation of a right line. 1879Thomson & Tait Nat. Phil. I. i. §134 The polar figure to any continuous curve on a spherical surface is the locus of the ultimate intersections of great circles equatorial to points taken infinitely near each other along it. 1895Electrician 10 May 43/1 (heading) Representation of periodic currents by polar diagrams. 1923Glazebrook Dict. Applied Physics IV. 429/2 These diagrams are what are generally termed ‘polar diagrams of light distribution’. In these curves the length of the radius vector at any angle gives the candle-power at that angle. 1943Electronic Engin. XVI. 241/1 The field strength relations and polar diagrams of several aerials..were discussed. 1962A. Nisbett Technique Sound Studio i. 20 (caption) In a polar diagram such as this the curve indicates the out⁓put of the microphone for a given sound arriving from any angle.
7. fig.
a. Analogous to the pole of the earth, or to the pole-star; of or pertaining to a central or directive principle.
1799Chron. in Ann. Reg. 156/1 Universal Emancipation, with Representative Legislature, was the polar principle which guided the Society of United Irishmen. 1858Carlyle Fredk. Gt. i. i. (1872) I. 4 A king over men; whose movements were polar, and carried..those of the world along with them. 1899A. Black in Expositor Jan. 51 Both the Church and the world depend in crisis on the man of insight:..the polar primary man.
b. Directly opposite in character, action, or tendency. (See also 4 a.)
1832J. Wilson in Blackw. Mag. XXXI. 998 Rusticity and Urbanity are polar opposites. 1840Carlyle Heroes iii. (1872) 90 Dante felt Good and Evil to be the two polar elements of this Creation, on which it all turns. 1953T. Parsons et al. Working Papers in Theory of Action 208 The instrumental and the system-integrative norms, which very closely characterize what..have been thought of as polar types of institutional structure. 1959McKinney & Loomis in J. S. Roucek Contemp. Sociol. 557 The polar extremes in point are clearly ideal or constructed types. Ibid. 558 The polar type formulations..have firmly established the point that the continuum is a vital notion in the comparative analysis of social phenomena. 1964E. A. Nida Toward Sci. Transl. ii. 24 The differences between literal and free translating are, however, no mere positive-negative dichotomy, but rather a polar distinction with many grades between them. 1965Language XLI. 275 Only the conjunction of ‘polar’ adjectives in contexts of this kind seems odd. 1972Sci. Amer. Jan. 35/1 Although sex-role ideologies form a continuum, we grouped the respondents into two polar categories, which we labeled ‘traditional’ and ‘contemporary’. 1975Language LI. 1 Polar interrogative sentences (‘yes/no questions’) are different from the corresponding declarative sentences not only pragmatically..but also semantically.
B. n. Geom. A curve related in a particular way to a given curve and a fixed point called the pole; in conic sections, the straight line joining the points at which tangents from the fixed point touch the curve.
1848G. Salmon Conic Sect. (1855) vi. §86 Whether the tangents from x′ y′ be real or imaginary, the line joining their points of contact will be the real line xx′ + vy′ = r2 which we shall call the polar of x′ y′ with regard to the circle. Ibid. xv. §302 The relation between the curves is reciprocal, that is..the curve S might be generated from s in precisely the same manner that s was generated from S; hence the name ‘reciprocal polars’. 1885C. Leudesdorf Cremona's Proj. Geom. 201 The straight line s determined in this manner by the point S is called the polar of S with respect to the conic; and, reciprocally, the point S is said to be the pole of the straight line s. |