| 释义 |
Thomson|ˈtɒmsən|
Also (erron.) Thompson.
1. Physics. [The name of Sir William Thomson: see Kelvin, kelvin.] Thomson effect: the effect an electric current has, when flowing in the direction of a temperature gradient, of absorbing or giving out heat independently of the Joule heating; so Thomson coefficient, a numerical measure of this effect for a material.
1878Encycl. Brit. VIII. 98/1 This anomaly led Tait to the discovery..that the Thomson effect in iron changes its sign..at a temperature near low red heat. 1906, etc. [see Seebeck]. 1930Engineering 9 May 596/2 The Thomson and Peltier coefficients were given values of the right general order of magnitude. 1966C. R. Tottle Sci. Engin. Materials vi. 130 By choosing appropriate values of the Peltier and Thomson coefficients, two dissimilar materials can be arranged to produce a substantial e.m.f. if one junction is maintained at a high temperature and the other at a lower one. 1975D. G. Fink Electronics Engineers' Handbk. xxvii. 3 At large values of dT/dx the Thompson effect may be comparable with the Seebeck effect and must be taken into account in the design of generators and refrigerators.
2. Zool. The name of Joseph Thomson (1858–94), Scottish explorer, used in the possessive (rarely attrib.) to designate an East African gazelle with a broad black lateral stripe, Gazella thomsoni, first collected by him and named in his honour by A. Günther in 1884 (Ann. & Mag. Nat. Hist. XIV. 428).
1897Proc. Zool. Soc. 454 Thomson's Gazelle does not..extend beyond a few miles north of Lake Nakuru. 1906[see Tommy1 3 c]. 1915Roosevelt & Heller Life-Hist. Afr. Game Animals II. xviii. 600 The Thomson gazelle is essentially a highland antelope. 1969Daily Tel. 13 Aug. 17/3 A Thomson's gazelle, born at Whipsnade Zoo, brings the number in the herd..to 20. 1980R. W. Hayman tr. Haltenorth & Diller's Field Guide Mammals Afr. 94 Thomson's Gazelle..horns lyre-shaped and weakly S-formed.
3. Physics. [The name of Sir J. J. Thomson (1856–1940), British physicist.] Thomson scattering: scattering of light by free charged particles, spec. electrons, in accordance with classical mechanics.
1935Compton & Allison X-Rays in Theory & Exper. (ed. 2) iv. 298 This classical scattering from a free electron is often called ‘J. J. Thomson scattering’. Ibid. 827/2 (Index), Thomson scattering. 1962Sci. Survey III. 123 Knowing the brightness of the corona and, from the theory of Thomson scattering, the proportion of sunlight scattered towards the observer by each electron, we can calculate the number of electrons per cubic centimetre. 1978Nature 19 Jan. 220/1 One..expects that up to a certain radial distance from the accretion column the neutron star surface is covered by a dense atmosphere and represents a ‘tarnished mirror’, reflecting quasi-isotropically by Thomson scattering. |