| 释义 |
directivity|dɪrɛkˈtɪvɪtɪ, daɪ-|
[f. directive a. + -ity.]
1. The quality or state of being directed by a vital force or power as distinguished from the physical forces, spec. as a theory of evolution.
1903Daily Chron. Apr., That directivity which could not be explained without the power of the Deity behind it. 1907Hibbert Jrnl. Oct. 150 Sheep, oxen, horses, and even geese may be feeding in the same grass-land. In each case the molecular compounds of the grass are identical, but they find themselves ultimately disposed in very different arrangements in the different animals. This can only be possible under the influence of directivity, but ‘directing’ differently in each creature.
2. The property or degree of being directional (see directional a. 5). Also attrib.
1928Jrnl. Inst. Electr. Engin. LXVI. ii. 955 General considerations of the directivity of beam systems. 1930Techn. News Bull., U.S. Bureau of Standards Dec. 117/2 Directivity of reception or transmission, or both, will inform the pilot of the direction of danger. 1935Proc. Inst. Radio Engin. XXIII. 357 Experiments with directivity steering for fading reduction. Ibid., It has been noticed in the past that fading was affected by the directivity of the receiving antenna. |