Search results
Results From The WOW.Com Content Network
A surface which obeys Lambert's law is said to be Lambertian, and exhibits Lambertian reflectance. Such a surface has a constant radiance / luminance , regardless of the angle from which it is observed; a single human eye perceives such a surface as having a constant brightness, regardless of the angle from which the eye observes the surface.
It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the response of the electronic structure of the material to the electromagnetic field of light, and is in general a function of the frequency, or wavelength, of the light, its polarization, and the angle of incidence.
Spectroscopic reflectance of a thin film on a substrate represents the ratio of the intensity of light reflected from the sample to the intensity of incident light, measured over a range of wavelengths, whereas spectroscopic transmittance, T(λ), represents the ratio of the intensity of light transmitted through the sample to the intensity of ...
In telecommunications and transmission line theory, the reflection coefficient is the ratio of the complex amplitude of the reflected wave to that of the incident wave. The voltage and current at any point along a transmission line can always be resolved into forward and reflected traveling waves given a specified reference impedance Z 0.
Time-domain thermoreflectance (TDTR) is a method by which the thermal properties of a material can be measured, most importantly thermal conductivity. This method can be applied most notably to thin film materials (up to hundreds of nanometers thick), which have properties that vary greatly when compared to the same materials in bulk. The idea ...
The Abeles matrix method [3] [4] [5] is a computationally fast and easy way to calculate the specular reflectivity from a stratified interface, as a function of the perpendicular momentum transfer, Q z: = =
The IPCC reports an outgoing thermal radiation flux (OLR) of 239 (237–242) W m-2 and a surface thermal radiation flux (SLR) of 398 (395–400) W m-2, where the parenthesized amounts indicate the 5-95% confidence intervals as of 2015. These values indicate that the atmosphere (with clouds included) reduces Earth's overall emissivity, relative ...
As it is an opaque material, the remaining 10 percent must be reflected. Conversely, a low-e material such as aluminum foil has a thermal emissivity/absorptance value of 0.03 and as an opaque material, the thermal reflectance value must be 1.0 - 0.03 =0.97, meaning it reflects 97 percent of radiant thermal energy. Low-emissivity building ...