| 释义 |
resiˈstivity
[f. resistive a. + -ity.]
1. Electr. The specific resistance of a substance, now usu. defined as the resistance of a conductor of unit length and unit cross-sectional area.
1885O. Heaviside in Electrician 4 Sept. 311/1 ‘Specific resistance’ may well be called ‘resistivity’. 1890Nature 9 Oct. 577/2 The..diameter of any of the conductors..divided by its electric resistivity. 1895[see -ivity]. 1943C. L. Boltz Basic Radio i. 26 Anyone capable of working out a formula can therefore find the resistance of any conductor by looking up the tables for specific resistance or resistivity. 1962Newnes Conc. Encycl. Electr. Engin. 658/1 Copper of the highest purity has a resistivity lower than that of any other known material except silver. A standard value for the resistivity of annealed copper was established in 1913 by the International Electrotechnical Commission as 0·017 241 Ω per m length and mm2 section. 1975Country Life 6 Feb. 331/3 The scientific techniques used by the archaeologists, such as the resistivity meters used to detect areas where the soil is broken up by the tops of mine shafts. 1975G. Anderson Coring vii. 121 The porosity of the sand is above 20% and the resistivity ranges from 0.3 ohm-m for saltwater sands to several ohm-meters for oil-saturated sands.
2. Special Combs.: resistivity surveying, measurement of the current passing between electrodes embedded in the ground at a series of positions over a given area, in order to identify regions of differing resistivity and hence locate buried structural features; so resistivity survey, a set or programme of such measurements.
1927Terrestrial Magnetism XXXII. 49 The Department of Terrestrial Magnetism of the Carnegie Institution of Washington has undertaken a series of resistivity surveys in regions where records of earth-current potential gradient are being obtained. 1952M. B. Dobrin Introd. Geophysical Prospecting xvi. 298 The interpretation of the actual data obtained in field resistivity surveys is usually a highly empirical and generally unreliable process. 1966McGraw–Hill Encycl. Sci. & Technol. XI. 22/2 Electromagnetic and electrical resistivity surveys are used to locate deposits of metallic sulfides, which, except for sphalerite, are good electrical conductors.
1931Engin. & Min. Jrnl. CXXXI. 325 (heading) Earth resistivity surveying. 1953R. J. C. Atkinson Field Archaeol. (ed. 2) i. 38 Resistivity surveying requires at least two operators, one at the instrument and one to move the electrodes. 1963Times 3 June 6/2 Resistivity surveying has been conducted by Mr. Whybrew, of the Ministry's test branch, and buried features have been detected. |