| 释义 |
orbital, a. and n.|ˈɔːbɪtəl|
[prob. ad. med. or mod.L. orbitāl-is, f. orbita orbit n.: see -al1.]
A. adj.
1. a. Anat. and Zool. Of, belonging to, or connected with the orbit or eye-socket.
1541R. Copland Guydon's Quest. Chirurg. E iij, The eyes..are set within the bone arbytall that is a party of the coronall, & the bones of the temples. 1828Stark Elem. Nat. Hist. I. 44 The Active Gibbon..forehead very low; orbital arches very prominent. 1870Rolleston Anim. Life 7 The temporal is never separated from the orbital fossa. 1878A. M. Hamilton Nerv. Dis. 168 The anterior lobe of the brain is composed of two divisions, the one inferior, or orbital, formed by the several convolutions called orbital.
b. Anthrop. orbital index [tr. F. indice orbitaire (P. Broca 1875, in Mém. de la Soc. d'Anthrop. de Paris II. 172)], one hundred times the ratio of the height of an orbit to its width.
1879A. de Quatrefages Human Species xxx. 388 The smallest orbital index known is that of the old man of Cro-Magnon, which we have seen to be 61·36. 1904W. L. H. Duckworth Stud. from Anthrop. Lab. Anat. Sch. Cambridge xvii. 104 The mean orbital index of thirty-one skulls is 82·6: that of twenty-four males 81·2; of three females 87·4. 1955Chambers's Encycl. I. 460/2 Similar conventional divisions of the orbital index..are: chamaeconchic (‘low orbits’) x–75·9, mesoconchic (‘medium orbits’) 76·0–84·9, and hypsiconchic (‘high orbits’) 85·0– x.
2. Of, belonging to, or of the nature of the orbit of a heavenly body; moving in an orbit; pertaining to such motion; taking place in an orbit, as orbital motion, orbital revolution (as distinguished from rotation on an axis).
1839Bailey Festus xxxi. (1852) 533 Its æras are all cycles; its events, How strange soe'er, are ever orbital. 1875Tait & Stewart Unseen Univ. (ed. 2) 126 That our earth will gradually lose its orbital energy and approach the sun by a slow spiral motion. 1932[see sense B below]. 1949W. Ley Conquest of Space (1950) 48 Probably the manned moonship will have to be postponed until there is an orbital station. 1951A. C. Clarke Exploration of Space 47 ‘Orbital refuelling’..is the key to interplanetary flight. It depends simply on the fact that once a spaceship had reached circular velocity outside the atmosphere, it would continue to orbit indefinitely without the use of power. 1961Guardian 6 May 1/4 The Mercury programme itself could be used as a means of sending men into substantially protracted orbital flights. 1961New Scientist 27 July 203 The advent of Midas in orbit raises the whole question of orbital warfare. Either manned or unmanned orbital bombers are an obvious starting point for such conceptions. 1962I. R. & M. W. Williams Basic Nucl. Physics i. 9 The innermost orbital electrons are the most tightly bound to the atom. 1970G. K. Woodgate Elem. Atomic Struct. iv. 55 A single-electron atom has a magnetic moment associated with the orbital motion of the electron. 1972M. G. Gross Oceanography ix. 243 (caption) Orbital motion and displacement of a water particle during the passage of a wave.
3. Designating a road, railway, or rail or road system encircling a large town; cf. ring-road. Also ellipt. as quasi-n., an orbital road.
1933Archit. Rev. LXXIV. 166/2 Orbital road system around London. 1937Times 13 Apr. (British Motor Suppl.) p. x/2 The plan may provide for orbital and radial roads, parkways, viaducts and tunnels, communications to aerodromes, railway stations, and docks. 1939N. & Q. 1 July 1/2 The proposal to thrust an orbital road through land belonging to the National Trust. 1967Times Rev. Industry Apr. 50/2 Essential features are good car parking space..and good communications. Orbital roads, motorways and similar positions are popular. 1970Times 3 Feb. 2 First priority for roads, after the orbitals outside Greater London, is Ringway 2 (North and South Circular Roads). 1975Country Life 16 Oct. 970 (caption) Near Great Warley. The London Orbital will pass across the fields in the middle distance. Ibid., The London Outer Orbital Route—a far-flung bypass..running around London. 1976Conservation News Nov./Dec. 7/2 Conservationists..are already presently split on their views of the proposed extension of the M25, London Outer Orbital Motorway. 1977Modern Railways Dec. 459/3 This would effectively establish one of the north orbital routes discussed in the Barran Committee's London Rail Study three years ago.
B. n. Physics and Chem. A possible pattern of electron density in space which can be realized by two electrons at the most in an atom or molecule; the wave function of a single electron corresponding to any such pattern.
1932R. S. Mulliken in Physical Rev. XLI. 50 From here on, one-electron orbital wave functions will be referred to for brevity as orbitals. The method followed here will be to describe unshared electrons always in terms of atomic orbitals but to use molecular orbitals for shared electrons. 1956Nature 11 Feb. 275/1 The resultant g values..will yield details on the orbitals involved in the chemical binding of the central iron atom. 1964J. W. Linnett Electronic Struct. Molecules i. 6 In quantum mechanics the orbits of the Bohr-Sommerfeld semi⁓classical methods are replaced by orbitals. Ibid. 9 Since each spatial orbital is defined by the three quantum numbers n, l and m, this [sc. the Pauli Principle] is equivalent to saying that each orbital can accommodate two electrons. 1970Sci. Amer. Apr. 54/2 Each orbital is characterized by a set of ‘quantum numbers’, denoting various properties of the electrons in that orbital (for instance their spin, angular momentum and the probability of finding the electrons in various regions of space). 1971J. Z. Young Introd. Study Man ii. 26 They are atoms able to receive electrons in the orbitals of their outer shell. |