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Ionization degree
The ionization degree is the fraction of a plasma's heavy particles that are ionized, the parameter that separates weakly ionized gas discharges from fully ionized fusion and arc plasmas.
Ionization energy
Ionization energy, formerly called the ionization potential, is the minimum energy needed to eject an electron from a neutral atom or molecule, forming a positive ion.
Ionization front
An ionization front is the sharp boundary between ionized and neutral interstellar gas, driven outward by ultraviolet light from hot stars and bounding H II regions.
Ionization gauge
An ionization gauge measures low gas pressures indirectly via ion current and is the standard instrument for high and ultrahigh vacuum, its two families being hot- and cold-cathode gauges.
Ionization injection
Ionization injection is a method for trapping electrons in a plasma wakefield accelerator, where a laser or particle beam ionizes dopant atoms inside the wake; it was first laser-demonstrated in 2010.
Ionization parameter
The ionization parameter is a dimensionless astrophysical quantity describing the balance between ionizing radiation and gas density in a nebula, defined as the ratio of ionizing photon flux to hydrogen density.
Ionized-air glow
Ionized-air glow, also called air fluorescence or nitrogen fluorescence, is ultraviolet and visible light emitted by excited nitrogen molecules in air bombarded by ionizing radiation.
Ionizing photon escape in early galaxies
Ionizing photon escape in early galaxies is the leakage of hydrogen-ionizing ultraviolet photons into the intergalactic medium. Its escape fraction decides whether star-forming galaxies could have driven cosmic reionization.
Ionizing radiation
Ionizing radiation is energy released by atoms as gamma rays, X-rays, or particles such as alpha, beta, and neutrons, energetic enough to remove electrons from atoms.
Ionomer resin
Ionomer resin is a thermoplastic polymer in which metal ions form ionic cross-links between polymer chains, giving toughness, clarity, and strong heat sealing; DuPont's Surlyn, introduced in the mid-1960s, is the best known.
Ionomer-induced poisoning of Pt fuel cell cathodes
Ionomer-induced poisoning of Pt fuel cell cathodes is the loss of oxygen reduction activity in PEM fuel cells when ionomer sulfonate groups adsorb on platinum, blocking catalytic sites.
Ionomycin
Ionomycin (SQ-23377) is a polyether antibiotic produced by the bacterium Streptomyces conglobatus that binds and transports calcium across membranes; it is widely used in cell biology research and in some fertility clinics for artificial oocyte activation.
Ionone
Ionone is a monocyclic terpenoid ketone, C13H20O, occurring as α and β isomers that smell of violets; over 1,000 metric tons are produced yearly for fragrances and flavors.
Ionophore
An ionophore, or ion carrier, is a compound that carries specific ions through cell or organelle membranes. Many are microbial antibiotics, including over 120 polyethers.
Ionosphere
The ionosphere is the ionized part of Earth's upper atmosphere, roughly 80 to 600 km up, reflecting radio waves for shortwave broadcasting and affecting satellite communication and navigation.
Ionospheric tomography
Ionospheric tomography is an inverse technique, introduced in 1988, that images ionospheric electron density from total electron content measured along radio paths between satellites and ground receivers.
Ionothermal synthesis
Ionothermal synthesis is a method for preparing crystalline inorganic solids, such as aluminophosphates and metal–organic frameworks, in which an ionic liquid serves as both solvent and template.
Iosif Shklovsky
Iosif Shklovsky (1916–1985) was a Soviet theoretical astrophysicist who explained the Crab Nebula's radiation as synchrotron emission and co-wrote Intelligent Life in the Universe with Carl Sagan.
Iota Herculis
Iota Herculis is a slowly rotating B3 subgiant of magnitude 3.82 in Hercules, about 455 light-years away, a slowly pulsating binary star used by astronomers as an abundance standard.
Iota Orionis
Iota Orionis, also known as Nair al Saif, is a massive multiple star system at the southern tip of Orion's Sword, with the most massive known heartbeat star.
Iota Pegasi
Iota Pegasi is a naked-eye double-lined spectroscopic binary star in the constellation Pegasus, about 38 light-years from Earth, where an F5 and a G8 star orbit every 10.2 days.
Iota Persei
Iota Persei is a yellow dwarf star of spectral type G0V in the constellation Perseus, about 34.4 light-years from the Sun, visible to the naked eye at magnitude 4.05.
Iota Piscium
Iota Piscium is a yellow-white F-type main-sequence star in the zodiac constellation Pisces, about 45 light years from the Sun and visible to the naked eye.
Iota Ursae Majoris
Iota Ursae Majoris, also called Talitha, is a quadruple star system about 47.3 light-years from the Sun in the constellation Ursa Major, visible to the naked eye.
Iota Virginis
Iota Virginis, named Syrma, is a yellow F-type giant of magnitude 4.08 in Virgo, about 72.5 light-years away and a probable binary with a 55-year orbit.
Ioxaglic acid
Ioxaglic acid is an ionic dimeric iodinated X-ray contrast medium sold under the brand name Hexabrix, developed by Guerbet in the 1970s and used in angiography and computed tomography.
IP camera
An IP camera, or network camera, is a video camera that sends digital video over an IP network instead of analog cabling, for viewing and recording from any connected device.
IP Pegasi
IP Pegasi is an eclipsing dwarf nova, a cataclysmic variable where a white dwarf accretes from a companion, with a 3.8-hour period and outbursts every 100 days.
IPCC Fifth Assessment Report
The IPCC Fifth Assessment Report (AR5) is the Intergovernmental Panel on Climate Change's fifth comprehensive assessment of climate change, issued by its three working groups and a Synthesis Report in 2013 and 2014.
IPCC Guidelines for National Greenhouse Gas Inventories
The IPCC Guidelines for National Greenhouse Gas Inventories are internationally agreed IPCC methods that countries use to estimate and report national greenhouse gas emissions and removals to the UNFCCC.