"The ratio between the emissive power
and the absorptive power is the same for all bodies at the same temperature".
It's all to do with emissivity, the term that describes the ratio of emissive power
of a surface at a given temperature to that of a black body at the same temperature and with the same surroundings.
For a relatively small area [A.sub.s] [(m.sup.2]) in a large enclosure at constant temperature [T.sub.a] (K), the irradiation to the surface from the surroundings equals the blackbody emissive power
of the surroundings.
It can improve the ultrasonic emissive power
that the push-pull form adds square signal at each end of ultrasonic transducer.
1 was presented in this form , the reflectivity term was viewed as reducing the emissive power
from arbitrary cavities.
Another approach, which is well suited to complex fenestration systems, is to formulate the nodal net radiation flux in terms of the effective emissivity and absorptivity coefficients of a layer medium, its nodal emissive power
and the incident radiation from all directions.
Now these particles, becoming incandescent, will radiate enormously more than the gaseous environment itself, at the same temperature, because their emissive power
is much superior to that of elementary gases or vapors.
As expected, the radiant heat transfer between the two surfaces is driven by black emissive power
and this heat transfer will be zero if either surface emissivity is zero.
Based on Magnus , Secchi advanced  that some condensed matter was present within the photosphere, as gases were devoid of the emissive power
required to produce the solar spectrum .
As such, relative to the Planck satellite LFI, the published return-loss values, do not properly represent the emissive power
of their reference targets.
While Stefan's law might appear to hold over narrow spectral ranges within the infrared, such band-like emissions fall far short of producing the emissive power
expected at all frequencies, through the application of the 4th power relationship.
Stewart's formulation leads to the realization that the emissive power
of any object depends on its temperature, its nature, and on the frequency of observation.