| 释义 |
thermionic, a. Physics.|θɜːmɪˈɒnɪk|
[f. prec. + -ic.]
Of, pertaining to, or employing electrons emitted from an incandescent surface; thermionic valve, an electronic device consisting of an evacuated envelope containing two or more electrodes, such that a current can flow only in one direction as a result of thermionic emission from one electrode.
1909O. W. Richardson in Phil. Mag. XVII. 814 Here we have two currents: the current used to heat the wire and the thermionic current away from the surface of the latter. 1915Electrician 21 May 241/1 The thermionic current..increased at first. 1917Wireless World June 152 The invention by the writer [sc. J. A. Fleming] of this article of the thermionic detector. Ibid. 158 Known by various titles, such as Fleming valve, vacuum valve,..thermionic valve, and audion valve, it is the result of experiments extending over a large number of years. 1920Glasgow Herald 9 July 10 What with the high-frequency alternator, and..the thermionic valve, wireless practice has been very much revolutionised. 1933Jrnl. Exper. Biol. X. 293 (heading) A thermionic potentiometer for measuring light intensity with photo-electric cells. 1956G. A. Montgomerie Digital Calculating Machines xi. 216 By using thermionic valves and similar devices, the speed of automatic computors can be made very much higher. 1957Times 26 Nov. 10/6 A new ‘thermionic converter’..takes advantage of the fact that electrons can be ‘boiled out’ of a hot metal surface and used to produce an electric current directly. 1975D. G. Fink Electronics Engineers' Handbk. xxvii. 18 In a thermionic generator..electrons are emitted from the heated cathode..and collected by a cooler anode.
So thermiˈonically adv.; thermiˈonics n. pl., the branch of science and technology concerned with thermionic emission.
1909O. W. Richardson in Phil. Mag. XVII. 814 The author ventures to suggest that the word ‘Thermionics’..is very suitable for the purpose. 1922J. Mills Within Atom vii. 74 When electrons are being thermionically emitted from a heated wire. 1933E. L. Chaffee Theory of Thermionic Vacuum Tubes i. 8 Early experimenters in the field of thermionics believed that the emission of electricity from hot bodies..was the result of some sort of chemical reaction. 1940Times 31 Aug. 7/4 New branches of knowledge like..photo-electricity, and thermionics sprang up out of the fertile soil. 1947Jrnl. Optical Soc. Amer. XXXVII. 424/2 Associated with this component of the dark current is a shot noise resulting from random thermionically emitted electrons. 1966McGraw-Hill Encycl. Sci. & Technol. XII. 542a/1 In thermionics, power densities of 25 watt/cm2 at emitter temperatures of 1700°C have been obtained with hardware which is suitable for [space] flight. |