| 释义 |
▪ I. Wien1 Physics.|viːn|
The name of Wilhelm Wien (1864–1928), German physicist, used attrib. and in the possessive to denote (a) an approximation to Planck's law that holds at short wavelengths, according to which the flux of radiant energy of wavelength λ emitted by a black body at temperature T is proportional to 1/λ5 exp (hc/λkT); (b) the displacement law (sense (i) s.v. displacement 2 e).
1899Astrophysical Jrnl. X. 40 My observations..make it seem possible that the law derived by W. Wien represents the emission of ‘the absolutely black body’. In Wien's formula, J = [etc.]. 1900Sci. Abstr. III. 383 Wien's laws, according to which the wave-length of the maximum radiation is inversely proportional to the absolute temperature, and the corresponding maximum energy proportional to the fifth power of the absolute temperature, were confirmed. 1904Wien's displacement law [see displacement 2 e]. 1948[see Rayleigh–Jeans]. 1963G. L. Pickard Descriptive Physical Oceanogr. v. 52 According to Wien's Law this energy is concentrated round a wavelength of 0.5µ. 1978Pasachoff & Kutner University Astron. ii. 24 From Wien's displacement law, we can see that the colors of stars in the sky are telling us something about their temperatures.
▪ II. Wien2|viːn|
[The name of M. C. Wien (1866–1938), German physicist.]
a. Electr. Wien bridge: an alternating-current bridge circuit devised by Wien which is used to measure capacitance (or frequency) in terms of resistance and frequency (or capacitance); Wien bridge oscillator: an oscillator based on this circuit.
1922Glazebrook Dict. Appl. Physics II. 1029/1 Wien bridge, for the measurement of the capacity and power factor of a condenser. 1957Practical Wireless XXXIII. 709/2 In Fig. 2 a simple bridge for capacitor testing is given. This is known as a Wien bridge. 1967Electronics 6 Mar. 63/3 (Advt.), Here, the RA-240 is used in the design of a highly stable, uncompensated Wien bridge oscillator. 1979R. Hamilton Electronics for Technicians vii. 157 The other type of R–C oscillator to be considered is known as a Wien bridge oscillator. (The name derives from a type of bridge circuit used in measurements, the feedback network of the oscillator being part of a balanced Wien bridge.)
b. Physical Chem. Wien effect: the increase in the electrical conductivity of an electrolytic solution as the field strength is increased.
1934R. P. Bell Electrolytes v. 90 The increase in conductivity [with frequency] is..of the same order of magnitude as the Wien effect. 1978P. W. Atkins Physical Chem. xxv. 832 The Wien effect is the observation of higher mobilities [of ions] at higher electric fields. (There are two Wien effects. The first Wien effect is the one just described; the second Wien effect is the enhancement of the degree of ionization of an ionogen, or weak electrolyte, by the applied field.) |