| 释义 |
scission|ˈsɪʃən|
[a. F. scission (14th c. in Hatz.-Darm.) (= It. scissione), ad. late L. scissiōn-em a cleaving or dividing, f. L. scindĕre (ppl. stem sciss-) to cut or divide.]
1. The action, or an act of cutting or dividing, as with a sharp instrument.
1676Wiseman Chirurg. Treat. v. iii. 357 Nerves may be many ways wounded, viz. by Scission or Puncture. 1835Kirby Hab. & Inst. Anim. I. Introd. 25 Mix them, and you have an animal which begins to absorb fluid, and..multiplies itself by scissions or germes.
2. fig. Division, separation; in early use = schism.
1443Sc. Acts Jas. II (1814) II. 33/1 Alsua at ferme & faste obedience be kepit til our haly fadir the pape Eugene..And at rigorouss processis be maid agaynis þe fauoraris of scissione, & the agaynstandaris of þe said obedience. 1736Hervey Mem. Geo. II, 252 A scission (which is the term the Poles have to express an election decided by arms and not by voices). 1789Jefferson Writ. (1853) II. 561 The Princes of the blood..presented and published a memoir, threatening a scission. 1798Ibid. IV. 246 If on a temporary superiority of the one party, the other is to resort to a scission of the Union, no federal government can ever exist. 1837Carlyle Fr. Rev. II. iii. iii. (1872) 97 Things ripen towards downright incompatibility and what is called ‘scission’. 1870Baring-Gould In Exitu Israel I. xiv. 185 The Church was divided into two classes,..and the scission between them was almost as sharp as that between the noble and the roturier. 1887Stevenson Merry Men, etc. (ed. 2) 123 He feared..some scission in the continuity of man's experience.
3. a. Chem. Breakage of a bond, esp. in a long chain polymer such that two smaller chains result.
1923Jrnl. Chem. Soc. CXXIII. i. 85 The scission of the ring..with elimination of nitrogen seems possible. 1944Jrnl. Appl. Physics XV. 389/2 For the case of Hevea and GR-S, the number of places along the chain that are subject to scission is not very large. 1952Turner & Harris Org. Chem. xxvii. 524 Another apparently reasonable alternative is that hydrazobenzene undergoes scission at the N—N link. 1975Nature 1 May 31/2 mRNA was treated with O.M NaOH for 4 min at o°C, which gave on average about one scission per molecule.
b. Nuclear Physics. The event of separation of the parts of a nucleus undergoing fission, as opposed to the process as a whole.
1956Physical Rev. CII. 440/1 The corresponding deformed shape roughly approximates the egg-shaped fragment resulting from scission of a dumbbell-shaped parent nucleus. 1958Rev. Mod. Physics XXX. 555/1 The separation of charge centers at the moment of scission. 1964L. Wilets Theories Nuclear Fission ii. 21 Of greater relevance to the fission process is the energy release to the point of scission, the time at which the fragment masses are unalterably determined. 1975Physics Bull. July 307/1 Dr Specht..concentrated on a description of those fission phenomena which seem to be decided by conditions in the nucleus at the time of scission rather than at the saddle point. |