All articles starting with S

Strontium oxide

Strontium oxide, also called strontia or strontium monoxide, is the strongly basic oxide of strontium, a grayish-white ionic solid used chiefly as a glass modifier and fluxing agent.

Strontium ruthenate

Strontium ruthenate (Sr2RuO4) is a layered perovskite that becomes superconducting below about 1.5 K, discovered in 1994 and studied for three decades as an unconventional superconductor.

Strontium titanate

Strontium titanate (SrTiO3, abbreviated STO) is a lead-free perovskite oxide of strontium and titanium, a model quantum material showing quantum paraelectricity and, when doped, superconductivity.

Strontium-87 optical lattice clock

A strontium-87 optical lattice clock is an atomic clock using thousands of laser-cooled strontium-87 atoms trapped in an optical lattice, accurate to parts in 10^18.

Strontium-89

Strontium-89 (⁸⁹Sr) is a radioactive isotope of strontium with a 50.5-day half-life that decays by beta emission and is used, as strontium-89 chloride, to relieve pain from bone metastases.

Strontium-90

Strontium-90, or Sr-90, is a radioactive isotope of strontium with a 29.1-year half-life, made in nuclear fission and infamous as a bone-seeking component of fallout.

Stroop effect: delayed ink-color naming when a word names an incongruent color, first reported by J. Ridley Stroop in 1935; the classic measure of selective attention, response inhibition, and frontal lobe function.

Sep 29, 2026

Stroop test

The Stroop test is a cognitive psychology task in which naming the ink color of a mismatched word, like red printed in blue, slows responses and raises errors.

Stroopwafel

Stroopwafel (syrup waffle): Dutch cookie of two thin waffle discs with syrup filling, invented in Gouda around 1810, credited to baker Gerard Kamphuisen; oldest recipe 1840, warmed on coffee.

Strophanthin

Strophanthin is a family of steroidal cardiac glycosides extracted from Strophanthus vine seeds, historically used as injectable drugs for heart failure and including ouabain, still used in the laboratory to inhibit the sodium pump.

Oct 21, 2026

Strophanthus

Strophanthus DC. (Apocynaceae), a genus of about 38-39 liana and shrub species from Africa to Malesia, source of cardiac glycosides such as ouabain, used as arrow poison and in heart medicine.

Oct 21, 2026

Strophanthus kombe

Strophanthus kombe (kombe arrow poison) is an East and southern African Apocynaceae liana whose glycoside-rich seeds served as arrow poison and yielded the heart medicine strophanthin-K, distinct from S. gratus (ouabain).

Oct 21, 2026

Strophomena

Strophomena is an extinct Ordovician (Caradoc–Ashgill) strophomenid brachiopod genus, type species Leptaena planumbona, a stationary epifaunal suspension feeder with a semicircular, resupinate shell, distinct from the mollusk Strophomenia.

Strossmayer Gallery of Old Masters

Strossmayer Gallery of Old Masters (Strossmayerova galerija starih majstora HAZU), Zagreb art museum founded by Bishop Josip Juraj Strossmayer, opened 9 November 1884 with 256 donated Old Master paintings in the HAZU Academy Palace; closed since the 2020 earthquake.

Stroszek

Stroszek (1977) is Werner Herzog's West German drama starring Bruno S., Eva Mattes, and Clemens Scheitz; a Berlin busker, a prostitute, and an eccentric emigrate to Wisconsin and find the American dream hollow. Written in four days for Bruno S., it won the German Film Critics' Award.

Strother Martin

Strother Martin (Strother Douglas Martin Jr.; 1919 to 1980) was an American character actor whose many Western roles included the chain-gang Captain in Cool Hand Luke (1967).

Stroud

Stroud is a Cotswold market town in Gloucestershire, England, once the center of a woollen cloth industry producing cloth known as Strouds, served by the 1779 Stroudwater Canal, and named the Sunday Times best place to live in the UK in 2021.

Strouhal number

The Strouhal number (St) is a dimensionless number defined as fL/U, relating periodic motion such as vortex shedding behind a bluff body to flow velocity and length.

Strowger switch

The Strowger switch, or step-by-step switch, is an electromechanical telephone switching device patented by Almon Strowger in 1891, in which dial pulses connect calls without an operator.

Struck by Lightning (book)

Struck by Lightning: The Curious World of Probabilities is a popular science book about probability in everyday life by statistician Jeffrey S. Rosenthal, published in 2005.

Struct (C programming language)

A struct in the C programming language is a composite data type grouping named members of different types into one object, introduced by Dennis Ritchie around 1972.

Structural adjustment

Structural adjustment, or structural adjustment programs, is development lending introduced by the World Bank in 1980, tying loans to reforms such as privatization, deregulation, and spending cuts.

Structural adjustment in Zambia

Structural adjustment in Zambia was a program of market-oriented reforms imposed through IMF and World Bank conditions, running from 1983 through the 1990s privatization of the state copper mines.

Structural adjustment programme in Nigeria

The structural adjustment program in Nigeria was a set of market-oriented reforms adopted in 1986 under General Ibrahim Babangida, combining exchange rate and trade liberalization to answer falling oil prices and rising debt.

Sep 29, 2026

Structural alignment of proteins

Structural alignment of proteins, also called multiple structure alignment, is a computational method that superimposes protein 3D structures to map corresponding residues, detect remote homologs, and classify folds.

Structural analysis

Structural analysis is the branch of engineering mechanics that determines the effects of loads on buildings, bridges, and other structures, predicting internal forces, stresses, displacements, and support reactions, most often using the finite element method.

Structural and Multidisciplinary Optimization

Structural and Multidisciplinary Optimization is a peer-reviewed Springer engineering journal founded in 1989 as Structural Optimization; it covers structural, fluid, thermal, and electromagnetic optimization and is ISSMO's official journal.

Structural battery

A structural battery is a multifunctional material that stores energy like a lithium-ion battery while carrying mechanical load, replacing added battery mass in electric vehicles, aircraft, and drones.