| 释义 |
radiometer|reɪdɪˈɒmɪtə(r)|
[f. radio- + meter.]
†1. An instrument formerly used for measuring angles; a cross-staff, forestaff. Obs.
1727–41in Chambers Cycl. 1802in James Milit. Dict.
2. An instrument invented by Sir W. Crookes, with the design of illustrating the transformation of radiant energy into mechanical force. Also, more generally, any device used to detect, or measure the intensity of, electromagnetic radiation (freq. spec. infra-red). Also extended to instruments (in the first cases adapted from Crookes's device) used to measure the intensity of sound by means of its radiation pressure.
1875Crookes in Proc. R. Soc. XXIII. 377 The luminous rays..repel the black surface more energetically than they do the white surface. Taking advantage of this fact, the author has constructed an instrument which he calls a radiometer. 1893Sir R. Ball Story of Sun 256 Highly rarefied gas like that contained in one of Mr. Crookes's radiometers. 1905R. W. Wood in Physical Rev. XX. 113 It occurred to me that a mill-wheel or radiometer driven by these [sound] waves would be useful for purposes of demonstration in treating of radiation pressure. 1920Q. Jrnl. R. Meteorol. Soc. XLVI. 399 (heading) The ether differential radiometer. 1927I. B. Crandall Theory Vibrating Syst. & Sound iv. 180 The radiometer is a simple torsion balance; a thin hollow metal box filled with air, on being submerged serves as a very good totally reflecting vane. 1930R. H. Baker Astron. x. 396 Abbot,..working with the 100-inch reflector, made use of delicate radiometers, having vanes of blackened bits of fly-wings, to measure the energy in different parts of the spectrum. 1963G. L. Pickard Descriptive Physical Oceanogr. vi. 92 The downward directed component of the long-wave radiation term..is determined by means of a radiometer. 1966McGraw-Hill Encycl. Sci. & Technol. XI. 317/1 Other radiometers use the pressure of sound waves to deflect a spherical body. Ibid. 317/2 The Crookes radiometer survives in jewelers' windows as a ‘perpetual motion’ device. 1969Times 19 Feb. 13/6 An infra-red radiometer will map the temperature across the surface of Mars. 1973Nature 20 Apr. 506/2 The radiometer was a load-switched superheterodyne microwave receiver. 1977R.A.F. News 11–24 May 11/1 Radiometers to measure infra-red and solar radiation.
attrib.1876Nature XIV. 288/2 The friction of the radiometer vanes with the rarefied air of the globe. Ibid. 508/1 The radiometer experiments were successful.
3. An instrument for determining the amount of X-radiation administered to a patient.
[1904Sci. Abstr. A. VII. 362 A ‘chromo-radiometer’ has been invented by Holzknecht, which consists of two parts—a measurer and a comparative scale.] 1912Med. Ann. 73 The..method of using Holzknecht's new radiometer for the more exact measurement of the x-ray dose. 1918R. Knox Radiogr. (ed. 2) II. 437 The radiometer is so sensitive that it is possible to measure with accuracy the pastille tint when it has not become nearly such a dark colour as in the case of the Sabouraud method. 1934H. Davies Pract. X-Ray Therapy iii. 31 (caption) Holzknecht radiometer, showing both halves of the pastille in position. |