- column density
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The total amount per unit area of a material suspended in a fluid or in a cloud in space, measured along the length of a column.
Wikipedia foundation.
Wikipedia foundation.
density gradient — A column of liquid in which the density varies continually with position, usually as a consequence of variation of concentration of a solute. Such gradients may be established by progressive mixing of solutions of different density (as for… … Dictionary of molecular biology
Eruption column — over Mount Pinatubo in the Philippines An eruption column consists of hot volcanic ash emitted during an explosive volcanic eruption. The ash forms a column rising many kilometres into the air above the peak of the volcano. In the most explosive… … Wikipedia
Particle density — The particle density or true density of a particulate solid or powder, is the density of the particles that make up the powder, in contrast to the bulk density, which measures the average density of a large volume of the powder in a specific… … Wikipedia
Low-Density-Parity-Check-Code — Low Density Parity Check Codes, auch als LDPC oder Gallager Codes bezeichnet, sind lineare Blockcodes zur Fehlerkorrektur. Sie wurden 1962 von Robert Gray Gallager im Rahmen seiner Dissertation am MIT entwickelt [1] [2]. Low Density Parity Check… … Deutsch Wikipedia
Low-density parity-check code — In information theory, a low density parity check code (LDPC code) is an error correcting code, a method of transmitting a message over a noisy transmission channel. [David J.C. MacKay (2003) Information theory, inference and learning algorithms … Wikipedia
Trihydrogen cation — Protonated molecular hydrogen, trihydrogen cation, or H3+, is one of the most abundant ions in the universe. It is stable in the interstellar medium (ISM) due to the low temperature and low density of interstellar space. The role that H3+ plays… … Wikipedia
Atmosphere of Mercury — Atmosphere of Mercury[1] Species CD,[n 1] cm−2 SD,[n 2] cm−3 … Wikipedia
Airmass — For air mass in meteorology, see air mass .In astronomy, airmass is the optical path length through Earth s atmosphere for light from a celestial source.As it passes through the atmosphere, light isattenuated by scattering and absorption; the… … Wikipedia
Extinction (astronomy) — Extinction is a term used in astronomy to describe the absorption and scattering of electromagnetic radiation by matter (dust and gas) between an emitting astronomical object and the observer. Interstellar extinction also called Galactic… … Wikipedia
Interstellar medium — Interstellar redirects here. For other uses, see Interstellar (disambiguation). The distribution of ionized hydrogen (known by astronomers as H II from old spectroscopic terminology) in the parts of the Galactic interstellar medium visible… … Wikipedia