42,772 articles
Functional renormalization group
The functional renormalization group (FRG) is a nonperturbative method in quantum field theory and statistical physics that describes how the effective action changes with an energy or momentum scale.
Functional renormalization of gravity
Functional renormalization of gravity applies the functional renormalization group, via Wetterich's effective average action, to quantum gravity, where a non-Gaussian fixed point suggests gravity is asymptotically safe.
Functional-group isomerism
Functional-group isomerism is a form of constitutional isomerism in which molecules share a molecular formula but belong to different families, like ethanol and dimethyl ether, both C2H6O.
Functionalized phenols
Functionalized phenols are phenol molecules bearing substituents such as halogen, nitro, or amino groups, whose electronic effects shift acidity from phenol's pKa of 10 to picric acid's 0.4.
Functor
A functor is a structure-preserving map between categories that sends objects to objects and morphisms to morphisms, introduced by Eilenberg and Mac Lane in 1945.
Fundamenta Mathematicae
Fundamenta Mathematicae is a Polish mathematics journal published in Warsaw by the Polish Academy of Sciences, founded in 1920 as the world's first specialized mathematical journal, devoted to set theory.
Fundamental domain
A fundamental domain is a subset of a space that contains exactly one representative of each orbit of a group action, so its translates tile the space.
Fundamental frequency
The fundamental frequency, also called the fundamental tone or first harmonic, is the lowest frequency of a periodic vibration, abbreviated F0 and measured in hertz.
Fundamental group
The fundamental group, also called the first homotopy group, is the group formed by the loops of a topological space up to continuous deformation, recording how loops wind around holes.
Fundamental interaction
A fundamental interaction, also called a fundamental force, is one of the four basic ways matter acts on matter: gravity, electromagnetism, and the weak and strong nuclear forces.
Fundamental plane
The fundamental plane is an empirical scaling relation of elliptical galaxies linking effective radius, surface brightness, and velocity dispersion, established in 1987 and used to measure distances.
Fundamental theorem of algebra
The fundamental theorem of algebra, also called D'Alembert's theorem, states that every nonconstant polynomial with complex coefficients has at least one complex root; a degree n polynomial has exactly n.
Fundamental theorem of arithmetic
The fundamental theorem of arithmetic, also called the unique factorization theorem, states that every integer greater than 1 factors into primes in only one way.
Fundamental theorem of calculus
The fundamental theorem of calculus links the two central operations of calculus, stating that differentiation and integration are inverse processes; its evaluation formula is the Newton–Leibniz formula.
Fundamental theorem of Galois theory
The fundamental theorem of Galois theory is a field theory theorem giving an inclusion-reversing correspondence between intermediate fields of a Galois extension and subgroups of its Galois group.
Fundamentals of Physics
Fundamentals of Physics is a calculus-based introductory physics textbook by David Halliday, Robert Resnick, and Jearl Walker, published by Wiley since 1974 and used in university courses for science and engineering students.
Funnel
A funnel, in the chemistry laboratory, is a cone-shaped piece of glass or plastic labware for transferring liquids or powders and for filtering, with special types such as Büchner and separatory funnels.
Funnel approach
The funnel approach is a questioning technique in which interviews or questionnaires begin with broad, open-ended questions and progress to narrow, specific ones; its inverse is the inverted funnel.
Funnel metadynamics
Funnel metadynamics (FM) is an enhanced-sampling molecular dynamics method, introduced by Limongelli, Bonomi, and Parrinello in 2013, that computes protein-ligand binding free energies using a funnel-shaped restraint.
Funnel plot
A funnel plot is a scatter plot of effect estimates against study size or precision in a meta-analysis, used to display small-study effects and assess publication bias.
Furan
Furan, also known as oxole or furfurane, is a flammable five-membered aromatic heterocycle, formula C4H4O, made from furfural and used to synthesize tetrahydrofuran, pyrrole, and thiophene.
Furan Diels–Alder aromatization to p-xylene
Furan Diels–Alder aromatization to p-xylene is a two-step catalytic route in which biomass-derived 2,5-dimethylfuran reacts with ethylene, then dehydrates to p-xylene, the feedstock for PET.
Furazolidone
Furazolidone, marketed as Furoxone, is a synthetic nitrofuran antimicrobial with antibacterial and antiprotozoal activity, first described in 1956, used for diarrhea, giardiasis, cholera, and H. pylori infection.
Furfural
Furfural, also known as Furol, is an aldehyde of furan produced from biomass such as corn cobs, used as a solvent in petroleum refining and as a chemical precursor.
Furfuryl alcohol
Furfuryl alcohol, or furan-2-ylmethanol, is a colorless liquid primary alcohol produced industrially by hydrogenating furfural, mainly to make furan resins used as foundry sand binders.
Furlong
A furlong is a British imperial and US unit of length equal to 220 yards, or one eighth of a statute mile, surviving mainly in horse racing.
Fusakichi Ōmori
Fusakichi Ōmori (大森房吉, 1868–1923) was a Japanese seismologist, professor at Tokyo Imperial University, who formulated the 1894 aftershock decay law and designed the Omori seismometer.
Fused bead preparation
Fused bead preparation is a sample preparation method for X-ray fluorescence in which a ground sample is dissolved in molten lithium borate flux and cast into a homogeneous glass disc.
Fused multiply-add
A fused multiply-add (FMA) is a floating-point operation that computes a × b + c with a single rounding, added to IEEE 754 in 2008.
Fused quartz
Fused quartz, also known as fused silica or quartz glass, is an amorphous silicon dioxide glass prized for very low thermal expansion and ultraviolet transparency.