| 释义 |
alternant, ppl. a. and n.|ælˈtɜːnənt, ɒl-|
[a. Fr. alternant, pr. pple. of alterner, ad. L. alternāre to alternate.]
A. adj.
1. Alternating, changing from one to the other.
a1640Jackson Creed x. xlii. Wks. IX. 492 Whatsoever is mutably good, or mutably evil..hath its alternant motions from God's decree.
2. Min. Consisting of alternating layers or laminæ.
1847in Craig.
B. n.
1. An alternating quantity.
1882Academy 21 Oct. 298/2 Chap. iii...gives in a concise form an account of continuants, alternants, symmetric determinants.
2. Logic. An alternative proposition or term; one of the components in an alternation (see alternation 7 b); = disjunct n.
1892W. E. Johnson in Mind I. 237 The alternants of the alternative synthesis a·b. 1912Mind XXI. 263 The argument..proves that there are alternants of universals like isosceles and scalene with respect to triangularity. 1921W. E. Johnson Logic I. iii. 31 In the alternative function ‘Either p or q’ p and q are alternants. Ibid. 36 It may very well be the case that the alternants in an alternative proposition are..‘exclusive’ to one another. 1957J. G. Brennan Handbk. Logic vi. 95 If at least one of the alternants must be true, then if one of them is false, the other is true.
3. Philol. The name given to any one of the possible variants found within any particular feature of speech or language. Cf. alternance.
1926L. Bloomfield in Language II. 160 Absence of sound may be a phonetic or formal alternant. 1942Bloch & Trager Outl. Ling. Analysis 57 We call the three forms /-ez, -z, -s/ alternants of the same morpheme. 1949C. E. Bazell in Archivum Linguisticum I. 2 There are variant expressions of the morpheme (the so-called morpheme-alternants) which may resemble the expressions of distinct morphemes in so far as they have no phonemes in common.
Add:[A.] 3. Chem. Designating or pertaining to a conjugated hydrocarbon whose rings each contain an even number of carbon atoms.
1947Coulson & Longuet-Higgins in Proc. R. Soc. CXCII. 19 As we move along any chain of unsaturated bonds the atoms will belong alternately to one set and to the other. For this reason we shall refer to such a hydrocarbon as an alternant hydrocarbon. 1952Jrnl. Amer. Chem. Soc. LXXIV. 3345/1 Most of the present discussion will be confined to alternant mesomeric systems. 1967I. L. Finar Org. Chem. (ed. 5) I. xxx. 808 Pyridine is an even-membered ring, and so is an alternant compound. 1980M. Orchin et al. Vocab. Org. Chem. iii. 64 This classification of hydrocarbons is significant in molecular orbital theory because alternant hydrocarbons possess complementary bonding and antibonding orbitals. |