42,772 articles
Filamentation
Filamentation is a nonlinear propagation regime in which an ultrashort, high-power laser pulse self-focuses in a transparent medium and travels as a self-guided plasma channel meters long.
Filip E. Du Prez
Filip E. Du Prez is a Belgian polymer chemist who has led the Polymer Chemistry Research group at Ghent University since 1999, known for vitrimers.
Filip Hjulström
Filip Hjulström (1902–1982) was a Swedish geographer and professor of physical geography at Uppsala University, known for the Hjulström curve relating river flow velocity to sediment erosion, transport, and deposition.
Filippo De Angelis
Filippo De Angelis is an Italian computational chemist who models dye-sensitized and perovskite solar cells, founding CLHYO and serving as Deputy Director at CNR-ISTM in Perugia.
Filippo Pilotta
Filippo Pilotta (born 1978) is an Italian independent researcher, a metalworker and physics autodidact, author of the self-published cosmology framework Synchronia Mundi – Relatività Comune.
Filippo Radicchi
Filippo Radicchi, born in Rome in 1978, is an Italian-born network scientist and Professor of Informatics at Indiana University Bloomington, known for his 2008 community detection benchmark.
Fill power
Fill power is a laboratory measure of the loft, or insulating capacity, of down: the volume in cubic inches one ounce occupies, typically ranging from about 300 to 900.
Filled skutterudite
A filled skutterudite is a thermoelectric material in which guest atoms fill the voids of the CoSb₃ crystal structure, suppressing heat conduction while keeping electrical conduction intact.
Film badge dosimeter
The film badge dosimeter, or film badge, is a personal radiation monitor of photographic film in a filtered plastic holder, worn by workers to measure external ionizing radiation exposure.
Film boiling
Film boiling is a boiling regime in which a continuous vapor film separates the heated surface from the liquid, insulating it so heat passes mainly by conduction and radiation.
Film dosimetry
Film dosimetry is the measurement of absorbed radiation dose from changes in a film's optical density, using radiographic or self-developing radiochromic film, now widely used in radiotherapy.
Filo del Sol
Filo del Sol is a copper-gold-silver deposit in the high Andes on the Argentina-Chile border, described by BHP as the largest greenfield copper discovery in 30 years.
Filter (mathematics)
In mathematics, a filter is a non-empty family of subsets closed under finite intersections and upward inclusion and excluding the empty set, introduced by Henri Cartan in 1937.
Filter (signal processing)
In signal processing, a filter is a system that selectively modifies a signal's frequency content, passing some frequencies while attenuating others, and exists in analog and digital form.
Filter model
A filter model is a mathematical model of the untyped lambda-calculus whose elements are filters of intersection types, introduced by Barendregt, Coppo, and Dezani-Ciancaglini in 1983.
Filter paper
Filter paper is a semi-permeable paper barrier placed perpendicular to a liquid or airflow, used to separate fine solid particles from liquids or gases in laboratory filtration.
Filter stability and approximation in nonlinear filtering
Filter stability is the property of a nonlinear filter whereby its estimates become insensitive to the initial condition as observations accumulate, and it underpins accurate particle filter approximation.
Filtration
Filtration is a separation process removing suspended solids from a liquid or gas by forcing the fluid through a porous medium such as filter paper or a sand bed.
Filtration (probability theory)
A filtration in probability theory is an increasing family of σ-algebras on a probability space, indexed by time, modeling the accumulation of information; it underlies martingales and stopping times.
Filtration method
The filtration method is a proof technique in modal logic that converts an infinite Kripke model of a formula into a finite one, proving the finite model property.
Final focus
The final focus is the last section of a particle collider's beam delivery system, using strong magnets to focus beams to nanometer-scale sizes at the interaction point where collisions occur.
Final parsec problem
The final parsec problem is the theoretical difficulty of merging a supermassive black hole binary from a separation of about one parsec down to gravitational-wave-driven scales.
Financial network
A financial network is the web of claims and exposures, such as interbank loans, among institutions like banks and hedge funds, through which shocks spread by contagion.
Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph
The Fine Guidance Sensor and Near Infrared Imager and Slitless Spectrograph (FGS/NIRISS) is a Canadian Space Agency instrument on the James Webb Space Telescope that guides pointing and performs near-infrared imaging and spectroscopy.
Fine particulate organic matter
Fine particulate organic matter (FPOM) is the organic fraction of particles between 0.45 and 1000 μm in streams and rivers, and a key food for collector invertebrates.
Fine structure
Fine structure is the splitting of otherwise degenerate atomic energy levels caused by relativistic and spin-dependent corrections, of order α² times the Bohr energy in hydrogen and visible as closely spaced spectral-line components.
Fine-structure constant
The fine-structure constant, also called Sommerfeld's constant, is a dimensionless constant of about 1/137 measuring the strength of the electromagnetic interaction, introduced by Arnold Sommerfeld in 1916.
Fine-tuned universe
The fine-tuned universe is the claim in physics and philosophy that life depends sensitively on the constants of nature; small changes would have prevented life from arising.
Fine–Gray model
The Fine–Gray model is a semiparametric proportional hazards regression model for the subdistribution hazard of a competing risk, proposed by Jason P. Fine and Robert J. Gray in 1999 and widely used as competing risks regression.
Fineness
Fineness is the content of a precious metal in an alloy, expressed in parts per thousand by mass, the standard measure for gold, silver, platinum, and palladium purity.