单词 | depressant |
释义 | depressantadj.n. Medicine. A. adj. a. Having the quality of lowering the activity of the vital functions; sedative. ΘΚΠ the world > health and disease > healing > medicines or physic > medicines for specific purpose > sedatives, antispasmodics, etc. > [adjective] > sedative, narcotic, or hypnotic stupefactive?a1425 sedativec1425 narcotic1526 opiate1543 narcotical1587 soporiferous1601 hypnotic1625 soporative1629 pacative1664 opiative1674 opiatic1678 thebaic1746 soporific1775 narcotico-acrid1815 depressant1887 opiumy1891 1887 Athenæum 13 Aug. 217/1 The depressant and narcotic action. 1892 N. Moore in Dict. National Biogr. XXIX. 221/1 The depressant treatment of fever. b. In ore and froth flotation: having the property of a depressant (sense B. c). ΚΠ 1945 A. F. Taggart Handbk. Mineral Dressing xii. 32 Lime..present in excess in sulphide flotation..has a definite depressant effect on the copper sulphides other than chalcopyrite. 1959 Chambers's Encycl. X. 235/2 Alkalis are generally depressant in action on all sulphide flotations, preventing the collectors from working. B. n. a. A medicine or agent having this quality; a sedative. ΘΚΠ the world > health and disease > healing > medicines or physic > medicines for specific purpose > sedatives, antispasmodics, etc. > [noun] > sedative sedative1797 depressant1876 psycholeptic1961 1876 S. W. Gross Gross's Pract. Treat. Dis. Bladder (ed. 3) i. ix. 267 The heart's action is reduced with aconite and other depressants. 1890 Standard 19 Nov. 3/6 Malaria and heat are remarkable depressants. b. Also depressent. A depressing influence. ΘΚΠ the mind > will > motivation > demotivation > [noun] > discouraging action or quality > a discouraging influence discouragement1574 disheartening1619 cold shower1875 depressant1894 disincentive1946 chilling effect1951 1894 R. L. Stevenson & L. Osbourne Ebb-tide i. v. 87 So strong a tonic to the merely weak, and so deadly a depressent to the merely cowardly. 1923 R. Kipling Irish Guards in Great War I. 121 There are times when Extreme Unction can be a depressant. 1961 Times 22 Mar. 18/3 To the ambitious athlete there is really no reason why standards should not be an incentive rather than a depressant. c. In ore and froth flotation, an agent that causes certain of the solids to sink while not affecting the others. ΚΠ 1934 Webster's New Internat. Dict. Eng. Lang. Depressant..Ore Dressing, a reagent that depresses. 1939 A. M. Gaudin Princ. Mineral Dressing xv. 393 Practical depressants for sulphide flotation include alkali hydroxides. 1951 Engineering 19 Oct. 492/1 Agents, known as depressants, are..used to promote wetting of..constituents, such as pyrites, which would otherwise float with the coal. 1962 Gloss. Terms Coal Preparation (B.S.I.) 24 Depressant, a substance which when added to a pulp prevents a particular mineral or minerals from floating. This entry has not yet been fully updated (first published 1895; most recently modified version published online June 2018). < adj.n.1876 |
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