| 释义 |
forward scattering
a. Physics. Scattering in which the direction of the scattered radiation or particles makes an angle of less than ninety degrees with the original direction.
b. Telecommunications. Scattering or reflection of high-frequency radio waves by irregularities in the troposphere or ionosphere so that some of their energy returns to earth beyond the horizon of the point of transmission. Hence (as a back-formation) forward-scatter v. trans.; also forward-scattered ppl. a.
1950Proc. IRE XXXVIII. 406/1 This formula for forward scattering applies no matter what may be the relation of the scale of turbulence to the wavelength. 1952Physical Rev. LXXXVI. 1 (heading) Forward scattering of light by a Coulomb field. 1953Jrnl. Geophysical Res. LVIII. 90 The amplitude of the forward-scattered signal exceeds that of an equivalent back-scattered signal. 1954Proc. IRE XLII. 530/1 Echoes forward-scattered from individual meteor ionization trails. 1967Rodberg & Thaler Introd. Quantum Theory of Scattering xii. 370 For a large target of uniform particle density..only forward scattering will occur. 1968W. G. Burrows V.H.F. Radio Wave Propag. 6 The propagation of a VHF wave beyond the radio horizon by forward scattering.
So forward(-)scatter n., (a) forward scattering (sense b); (b) radio waves that have returned to earth after being scattered in this way. Also attrib.
1954Canad. Jrnl. Physics XXXII. 450 Reflections from meteoric trails can support, intermittently, high frequency radio transmissions well beyond the line-of-sight... The Stamford workers have developed a theory of this forward-scatter transmission. 1956Ann. Reg. 1955 409 Waves reflected from the E-layer..and sent on by ‘forward scatter’. 1958Times 30 Apr. 6/6 Experiments are to be carried out in Britain to ascertain whether television pictures can be transmitted by the ‘forward scatter’ technique over distances of 200 miles or more. 1960Gloss. Terms Telecomm. (B.S.I.) 168 A signal received by forward scattering is often referred to as forward scatter. |
