| 释义 |
Newton|ˈnjuːtən|
[Name of Sir Isaac Newton: see Newtonian a. and n.]
1. Newton's rings: a set of concentric circular fringes seen surrounding the point of contact when a convex lens is placed on a plane surface (or on another lens), which join points where the intervening thin layer of air has the same thickness and are caused by interference between light reflected from its upper and lower surfaces. When used attrib. also sing.
[1807Phil. Trans. R. Soc. XCVII. 180 (heading) Experiments for investigating the cause of the coloured concentric rings, discovered by Sir Isaac Newton, between two object-glasses laid upon one another. 1809Ibid. XCIX. 299 In order completely to account for the Newtonian rings.] 1835Phil Mag. VII. 363 In examining Newton's rings I was induced to place a convex lens..between two surfaces of plate-glass, in order to effect the superposition of the rings. 1904A. Schuster Introd. Theory of Optics iv. 72 The colours observed in Newton's rings are the colours of thin films, the film being the layer of air included between the lens and the plate. 1969S. G. & H. Lipson Optical Physics xii. 382 Lens surfaces can be tested to a high degree of accuracy by forming Newton's rings with a known surface. Ibid. 383 Coefficients of thermal expansion of quite small crystals can be measured by counting the fringes that pass through the centre of a Newton's ring system as the crystal is heated.
2. (Written newton.) The unit of force in the metre-kilogramme-second system (now incorporated in the S.I.): the force that would give a mass of one kilogramme an acceleration of one metre per second per second; 100,000 dynes (approximately the weight of 102 grammes or 3·6 oz.). Abbrev. N.
1904D. Robertson in Electrician 22 Apr. 25/1 The writer suggests that the name ‘Newton’ be given to the unit of force (105 dynes). 1919Nature 4 Sept. 13/2 A fourth matter..which was discussed was the proposal to adopt in future legislation for metric countries the M.K.S. system of units... On this system the unit of force is the ‘Newton’. 1935Hartshorn & Vigoureux in Ibid. 7 Sept. 397/2 In the M.K.S. system..no name has yet been assigned to the unit of force... G. Giorgi has provisionally used the word ‘vis’... We venture to suggest that ‘newton’ would be more appropriate. 1942H. Howe Introd. Physics iv. 57 The awkwardly large numbers in Ex. 2 would have been avoided had mks units been used; the answer would have been F = 300 newtons. 1962Corson & Lorrain Introd. Electromagnetic Fields ii. 29 In these units Coulomb's law is written as F ab = (1/4πεο) (QaQb/r2)/r1, where the force F is measured in newtons; the charges Qa and Qb, in coulombs..; and the distance r, in meters. 1970Daily Tel. 14 May 18 In the SI the force is measured not in kilogrammes, but in newtons—spelt with a small ‘n’ but abbreviated with a large one, ‘N’. One newton (reinforcing the legend) is roughly the pull of gravity on one apple. |