42,772 articles
Infinity symbol
The infinity symbol (∞), also known as the sideways eight or infinity sign, is a mathematical sign for infinite quantity, introduced by English mathematician John Wallis in 1655.
Inflaton
The inflaton, or inflaton field, is a hypothetical scalar field whose potential energy is thought to have driven cosmic inflation, the rapid early expansion of the Universe.
Inflection point
An inflection point, also written point of inflection or inflexion point, is a point on a function's graph where concavity changes, so the second derivative changes sign.
Inflow tail
An inflow tail is a band of low cloud marking warm, moist air drawn into a supercell thunderstorm's updraft, including the tail cloud and the beaver tail.
Influence function (statistics)
The influence function, also called the influence curve, is a statistic measuring a single outlier's effect on an estimator's asymptotic version, introduced by Frank Hampel in 1974.
InFocus
InFocus is an American audiovisual technology company founded in 1986 in Oregon by Steve Hix and Paul Gulick, known for projectors including the first digital and DLP projectors.
Informant interview
An informant interview is an in-depth qualitative interview with someone chosen for first-hand knowledge about a group, used to describe it rather than measure a population.
Information
Information is a quantifiable measure of resolved uncertainty, formalized by Claude Shannon in his 1948 paper A Mathematical Theory of Communication, with the entropy formula and the bit as its unit.
Information theory
Information theory, also known as Shannon theory, is the mathematical study of the quantification, storage, and transmission of information, founded by Claude Shannon in his 1948 paper.
Infrared
Infrared, also called infrared radiation or infrared light, is electromagnetic radiation beyond visible red, discovered by William Herschel in 1800 and used for thermal imaging.
Infrared Astronomical Satellite
The Infrared Astronomical Satellite (IRAS) was the first space telescope to survey the entire sky in infrared light, a 1983 joint project of the United States, the Netherlands, and the United Kingdom.
Infrared heater
An infrared heater, also called a heat lamp, is a heating device that warms people and objects directly by infrared radiation instead of warming the air first.
Infrared ion spectroscopy
Infrared ion spectroscopy is a family of gas-phase methods that measures infrared absorption of mass-selected ions indirectly, mainly to distinguish isomers that mass spectrometry alone cannot resolve.
Infrared microscopy
Infrared microscopy combines an infrared spectrometer with a microscope to record absorption spectra at many points across a sample, producing false-color chemical images used in tissue, pharmaceutical, and microplastics analysis.
Infrared microspectroscopy
Infrared microspectroscopy is an analytical technique that combines an infrared spectrometer with a microscope to identify and map chemical components in materials at microscopic resolution, with uses in biomedical science, microplastics research, and forensics.
Infrared multiphoton dissociation
Infrared multiphoton dissociation (IRMPD) is a tandem mass spectrometry method that fragments trapped gas-phase ions by resonant absorption of many infrared photons, introduced in 1979 and also used for vibrational spectroscopy of stored ions.
Infrared nano-imaging of graphene plasmons
Infrared nano-imaging of graphene plasmons is the real-space visualization of plasmons in graphene at nanometer resolution using a sharp AFM tip, first achieved in two 2012 Nature papers.
Infrared reflection absorption spectroscopy
Infrared reflection absorption spectroscopy (IRAS, also RAIRS or IRRAS) is a surface-sensitive vibrational technique that identifies molecules adsorbed on reflective metal surfaces and their bonding geometry.
Infrared Space Observatory
The Infrared Space Observatory (ISO) was a European Space Agency satellite with a 60 cm helium-cooled telescope that made nearly 30,000 infrared observations between 1995 and 1998.
Infrared spectroscopic ellipsometry
Infrared spectroscopic ellipsometry is a contactless, nondestructive optical technique measuring how infrared light's polarization changes on reflection, yielding dielectric functions, phonon properties, and free-carrier data.
Infrared spectroscopic imaging
Infrared spectroscopic imaging combines an infrared spectrometer with a microscope to record a full mid-infrared spectrum at each pixel, mapping chemical composition label-free for applications such as digital histopathology.
Infrared spectroscopy
Infrared spectroscopy, also known as IR spectroscopy, is an analytical technique that measures which infrared frequencies a sample absorbs, revealing molecular structure and chemical identity.
Infrared thermal imaging
Infrared thermal imaging is a passive remote sensing technique that records infrared radiation emitted by surfaces and converts it into temperature maps without contact, used in handheld cameras and satellites.
Infrared thermometer
An infrared thermometer, also known as a laser thermometer or temperature gun, is a non-contact instrument that measures temperature from the thermal radiation an object emits.
Infrasound
Infrasound, or infrasonic sound, is sound below about 20 Hz, beneath human hearing, used to monitor nuclear explosions, volcanic eruptions, and meteors and by elephants to communicate over long distances.
Inge Lehmann
Inge Lehmann was a Danish seismologist who in 1936 discovered that the Earth has a distinct inner core, and headed seismology at the Danish Geodetic Institute.
Ingersoll Watch Company
The Ingersoll Watch Company was an American firm founded by Robert H. Ingersoll and his brother in New York, known for the mass-produced Yankee dollar watch.
Inglehart–Welzel cultural map of the world
The Inglehart–Welzel cultural map of the world is a two-dimensional map of national values built from World Values Survey data by Ronald Inglehart and Christian Welzel.
Ingleton's inequality
Ingleton's inequality is a linear inequality on matroid ranks, proved by Aubrey Ingleton in 1971, that holds for every matroid representable over a field but is not implied by the rank axioms.
Ingo Krossing
Ingo Krossing is a German inorganic chemist, professor at the University of Freiburg since 2006, known for weakly coordinating anions and unified acidity and redox scales.