| 释义 |
ˈend-point
[f. end n. + point n.1]
The end or latter part of a period, process, etc.
1. spec. in Chem., etc. The point in a titration, or the stage of a process of dilution, at which a definite effect is observable.
1899Henderson & Parker Introd. Anal. Chem. 114 The exact point at which neutralization takes place (‘the end point’) is determined by means of an indicator. 1919Chemist & Druggist XCI. 243 The solution is very slowly decolorised at first... The end point was taken as the faintest visibly pink tint, permanent for one minute. 1946Nature 19 Oct. 556/2 The concentration of chloride in the blood of agouti and black mice has been investigated..but with only 0.22 c.c. of serum the end-point is not certain. 1956Ibid. 18 Feb. 303/2 Tobacco seedlings show systemic symptoms sooner when inoculated with tobacco sap diluted almost to the infection end-point than when they are inoculated with undiluted sap from infected Prince beans. 1961Lancet 29 July 228/1 In the tube dilution methods the end-point was taken as the last tube showing visible growth after 48 hours incubation at 35–37°C. 1963Ibid. 5 Jan. 52/2 ‘Total acid’ meant titratable acidity to an end-point about pH 8–10 (phenolphthalein).
2. transf. and fig.
1921E. Sapir Language (1922) v. 115 The starting-point and end-point of the flow of activity. 1927L. Clendening Human Body iv. 109 (caption) An air sac. The end point of a lung branch. 1959J. C. Catford in Quirk & Smith Teaching of English vi. 183 The variations in the vertical dimension..represent..different types of end-point, or ‘second term’, for the relations represented. 1965W. S. Allen Vox Latina ii. 60 Scaurus..who comments on the current end-point of the dipthong as e rather than i. |