| 释义 |
▪ I. mu|mjuː|
[a. Gr. µῦ, name of the letter Μ, µ (see M).]
1. One micrometre (micron). Usu. denoted by µ.
[1880: see micron.] 1888Nature 8 Mar. 438/1 Micron is currently used here to express 1/1000 of a millimetre. French botanists call it µ, and seldom use its first decimal because they cannot see such a small space. 1900Dorland Med. Dict. 398/2 Mu, in micrometry, a micron or micro⁓millimeter. 1957Jrnl. Anat. XCI. 2 The mean nuclear volume in six [vole] oocytes was found to be 5200 µ3. 1958Times Rev. Industry June 53/2 It [sc. the Mercast process] yields castings to extremely close dimensional limits, one example quoted being..a surface finish of 60µ an inch or better. 1959Listener 31 Dec. 1161/1 Cell sizes range from a few mu to a few dozens of mu. 1970Ambrose & Easty Cell Biol. i. 7 Bacteria..vary greatly in size from a diameter of 5,000 Å for the cocci up to about 20 µ in length for some of the filamentous bacteria.
2. Electronics. The amplification factor of a valve.
1918H. J. van der Bijl in Physical Rev. XII. 184 The factor µ0, which plays a very important part in the theory of operation of the thermionic amplifier, can be more easily and accurately determined with the help of equation (19), which gives the relation between the anode and grid potentials necessary to maintain the current at some convenient constant value. Ibid. 192 The voltage amplification µ is given by µ = µ0R/(R + R0). 1927B. F. Dashiell Pop. Guide Radio vi. 98 The amplification constant of a tube, usually designated as mu, is a measure of the relative effect of changing the grid bias compared to changes in the plate voltage. 1931Electronics Apr. 609/1 Mutual conductance meter... The compensator dial is set for the value most nearly corresponding to the ‘Mu’ of the tube under test. 1962Newnes Conc. Encycl. Electr. Engin. 860/1 A coarse-pitch grid gives a low magnification and requires greater bias to cutoff. In the variable-mu valve the grid is graded, and this gives a valve whose gain can be altered by changing the bias applied to it.
▪ II. mu
var. mou. |