All articles starting with Q
2,252 articles
Quadrilateral
A quadrilateral is a polygon with four sides and four vertices, such as a square, rectangle, parallelogram, or trapezoid, with interior angles summing to 360°.
Quadrilateral Security Dialogue
The Quadrilateral Security Dialogue (Quad) is an informal partnership of Australia, India, Japan, and the United States, established in 2007 after the 2004 Indian Ocean tsunami and revived in 2017. Unlike NATO, it has no mutual-defense pact, operating through summits and working groups on maritime security, technology, and infrastructure.
Quadrilha
Quadrilha is a short 1930 poem by the Brazilian poet Carlos Drummond de Andrade, from his debut collection Alguma Poesia, tracing unrequited loves among six characters.
Quadrille
Quadrille, an 18th-century four-player trick-taking card game adapted from Spanish Hombre/Ombre, played with a 40-card deck and a called-King secret partner; Europe's most fashionable card game before Whist displaced it.
Quadrinhos brasileiros
Quadrinhos brasileiros, also called histórias em quadrinhos, are comics produced in Brazil since Angelo Agostini's Nhô Quim of 1869, later spanning children's magazines like Turma da Mônica and graphic novels.
Quadriporticus of the theatre
Quadriporticus of the Theatres (Caserma dei Gladiatori), Pompeii VIII.7.16: a courtyard behind the Large Theatre ringed by 74 Doric Nocera-tuff columns, built as a theatre foyer and converted after the AD 62 earthquake into gladiators' barracks.
Quadrivalent influenza subunit vaccine
Quadrivalent influenza subunit vaccine (慧尔康欣, Hui Erkang Xin), China's first quadrivalent subunit flu vaccine by Jiangsu Ab&B Bio-Tech, NMPA-approved May 2023, covering H1N1, H3N2, BV, BY with 15 µg HA per strain.
Quadrivium
The quadrivium is the group of four mathematical arts of the classical seven liberal arts: arithmetic, geometry, music, and astronomy. It followed the trivium in medieval university education.
Quadro
Quadro was NVIDIA's brand of professional workstation graphics cards, launched in November 1999 and sold for more than 20 years before the line was rebranded as NVIDIA RTX.
Quadrobics
Quadrobics ("quads") is moving on all fours imitating animal gaits like trot, pace, bound, gallop. Emerging in the 2000s from Kenichi Ito's four-limbed 100 m record, Crawling, Animal Flow, and parkour, it went viral on TikTok (300,000+ videos by May 2024), carries parkour-level injury risk, and remains a movement practice, not a sanctioned sport.
Quadroon
Quadroon: dated, offensive English term for a person of one-quarter Black ancestry (one Black grandparent), offspring of a mulatto and a white parent; used in the 1890 US census and Louisiana law, from Spanish cuarterón.
Quadrophenia
Quadrophenia is The Who's sixth studio album, a 1973 double rock opera written by Pete Townshend about mod Jimmy, whose split personality mirrors the four band members; it reached No. 2 in the UK and US and inspired the 1979 film.
Quadrophenia (film)
Quadrophenia (1979) is Franc Roddam's debut British drama film, loosely adapted from The Who's 1973 rock opera album, starring Phil Daniels as mod teenager Jimmy Cooper amid the 1965 mods-versus-rockers clashes in Brighton, with Sting in his debut role.
Quadruple bond in C2
The quadruple bond in C2 is a proposed description of bonding in the dicarbon molecule, with a weak fourth bond added to one σ and two π bonds, proposed by Sason Shaik in 2012.
Quadruplet pregnancy
Quadruplet pregnancy, a higher-order multiple gestation with four fetuses (ICD-11 JA80.2, ICD-10 O30.2), occurs naturally about 1 in 700,000 conceptions and carries high risks of preterm delivery, maternal complications, and neonatal loss.
Quadruplex telegraph
The quadruplex telegraph, also called the quadruplex system, is a telegraph system that sends four messages at once over a single wire, two in each direction.
Quadrupolar order
Quadrupolar order is a type of electronic order in solids in which the electric quadrupole moments of ions align into a long-range pattern without magnetic order, studied chiefly in cubic Pr compounds.
Quadrupole
A quadrupole is the third term in the multipole expansion of an electric, magnetic, or gravitational field, arising when the monopole and dipole moments of a charge distribution vanish.
Quadrupole formula
The quadrupole formula, first derived by Einstein in 1916 and corrected in 1918, gives the energy radiated as gravitational waves by an isolated mass distribution.
Quadrupole interaction
The quadrupole interaction is an electrostatic interaction involving the quadrupole moment, the second-rank moment remaining after charge and dipole; it shapes the adsorption and phase behavior of molecules like CO₂.
Quadrupole magnet
A quadrupole magnet, or Q-magnet, is an accelerator magnet with four poles that focuses a charged-particle beam in one plane and defocuses it in the other.
Quadrupole mass spectrometry
Quadrupole mass spectrometry separates and detects ions by mass-to-charge ratio using oscillating radiofrequency and DC fields between four parallel rods, and anchors GC-MS, LC-MS/MS, and ICP-MS.
Quadrupole time-of-flight mass spectrometry
Quadrupole time-of-flight mass spectrometry (Q-TOF-MS, also written QTOF or QqTOF) is a tandem mass spectrometry technique that combines a quadrupole mass filter with a high-resolution time-of-flight analyzer.
Quadrupole topological insulator
A quadrupole topological insulator (QTI) is a two-dimensional higher-order topological insulator whose quantized bulk quadrupole moment appears as in-gap corner states rather than conducting edges.
Quadrupole triplet lens
A quadrupole triplet lens is a beam-focusing system of three quadrupole lenses with alternating polarities, used to focus charged-particle beams to micrometer-scale spots in nuclear microprobes.
Quadtree
A quadtree, or quadtree decomposition, is a tree data structure in which each node has four children, one per quadrant, used for spatial indexing and image encoding.
Quaestor
Quaestor: Roman magistrate, lowest office of the cursus honorum, mainly financial (treasury, provincial revenue). Numbers grew from two to twenty under Sulla, forty under Caesar; late imperial quaestor sacri palatii drafted laws.
Quagga
Quagga (Equus quagga quagga), extinct South African subspecies of the plains zebra with a striped front and unstriped rear, extinct 1883; first extinct species with DNA recovered (1984), now target of the Quagga Project back-breeding program.
Quai des Orfèvres
Quai des Orfèvres is a 1947 French crime film by Henri-Georges Clouzot, adapted from Stanislas-André Steeman's Légitime défense, starring Louis Jouvet, Suzy Delair, and Bernard Blier; it won Venice's best director prize and revived Clouzot's post-blacklisting career.
Quaise Energy
Quaise Energy is an American energy company spun out of MIT in 2018 that is developing millimeter wave drilling to reach superhot geothermal resources deeper than mechanical drills can go.