In
A spectral index of -.1 typically indicates thermal, or free-free (
Wikimedia Foundation. 2010.
spectral index — … Useful english dictionary
spectral — index immaterial, insubstantial Burton s Legal Thesaurus. William C. Burton. 2006 … Law dictionary
Spectral energy distribution — A spectral energy distribution (SED) is a plot of flux, brightness, or flux density versus frequency or wavelength of light. It is used in many branches of astronomy to characterize astronomical sources. For example, in radio astronomy, an SED… … Wikipedia
Spectral music — (or spectralism) refers to a musical composition practice where compositional decisions are often informed by the analysis of sound spectra. Computer based sound spectrum analysis using a Fast Fourier transform is one of the more common methods… … Wikipedia
Spectral method — Spectral methods are a class of techniques used in applied mathematics and scientific computing to numerically solve certain Dynamical Systems, often involving the use of the Fast Fourier Transform. Where applicable, spectral methods have… … Wikipedia
Spectral sequence — In the area of mathematics known as homological algebra, especially in algebraic topology and group cohomology, a spectral sequence is a means of computing homology groups by taking successive approximations. Spectral sequences are a… … Wikipedia
Spectral theorem — In mathematics, particularly linear algebra and functional analysis, the spectral theorem is any of a number of results about linear operators or about matrices. In broad terms the spectral theorem provides conditions under which an operator or a … Wikipedia
Spectral theory of ordinary differential equations — In mathematics, the spectral theory of ordinary differential equations is concerned with the determination of the spectrum and eigenfunction expansion associated with a linear ordinary differential equation. In his dissertation Hermann Weyl… … Wikipedia
Spectral phase interferometry for direct electric-field reconstruction — In ultrafast optics, spectral phase interferometry for direct electric field reconstruction (SPIDER) is an ultrashort pulse measurement technique.The basicsSPIDER is an interferometric ultrashort pulse measurement technique in the frequency… … Wikipedia
Spectral theory — In mathematics, spectral theory is an inclusive term for theories extending the eigenvector and eigenvalue theory of a single square matrix. The name was introduced by David Hilbert in his original formulation of Hilbert space theory, which was… … Wikipedia
