All articles starting with S

Straight-twin engine

A straight-twin engine, also called a parallel-twin or inline-twin, is a two-cylinder piston engine with both cylinders in a single row, used chiefly in motorcycles.

Sep 19, 2026

Straightener

Straightener (ストレイテナー) is a Japanese alternative rock band formed in Tokyo in 1998 by Atsushi Horie and Shinpei Nakayama, a four-piece since 2008 with over ten studio albums.

Straightlining

Straightlining, also called response non-differentiation, is a survey response pattern where a respondent gives identical or nearly identical answers to every item on a rating grid.

Strain (biology): a lineage of microbes descended from a single pure-culture isolation, or a distinguishable genetic/phenotypic variant within a species; distinct from isolate and clone, defined by typing methods such as MLST and PFGE.

Strain (injury)

Strain (injury): an overstretched or torn muscle or tendon, also called a pulled muscle, distinct from a ligament sprain. Common in legs, feet, and back; treated with PRICE therapy; graded I–III or by MRI.

Strain (mechanics)

In mechanics, strain measures the deformation of a material body as relative changes in length and angle, excluding rigid motion; it is a symmetric second-rank tensor with six independent components.

Strain aging

Strain aging is a change in the mechanical behavior of a deformed metal that occurs when carbon and nitrogen atoms diffuse to dislocations and pin them, raising yield strength.

Sep 29, 2026

Strain elastography

Strain elastography is an ultrasound technique that images how tissue deforms under light compression, showing relative stiffness to help assess lesions in the breast and thyroid.

Sep 29, 2026

Strain engineering

Strain engineering deliberately applies elastic strain to crystals or thin films to change their properties; strained silicon became standard in 90, 65, and 45 nm CMOS logic.

Strain engineering of monolayer transition metal dichalcogenide band gaps

Strain engineering of monolayer transition metal dichalcogenide band gaps is the use of mechanical strain to tune the band gaps of atomically thin semiconductors like MoS2.

Strain feedback control

Strain feedback control is a method for flexible-link robots in which strain gauges on the link feed back to actuators, damping vibration and positioning the tip.

Strain gauge

A strain gauge is a sensor whose electrical resistance changes as it is stretched or compressed, used in load cells and stress analysis of aircraft and bridges.

Strain gradient theory

Strain gradient theory is a family of non-classical elasticity theories in which strain energy depends on strain gradients, explaining size-dependent behavior of micro- and nanostructures.

Sep 29, 2026

Strain imaging

Strain imaging is an ultrasound technique that measures how tissue deforms under light compression, displaying relative stiffness as a color map to distinguish benign from malignant lesions.

Strain index

The Strain Index is a job analysis method that predicts risk of hand, wrist, and forearm disorders from repetitive, forceful hand work, published by Moore and Garg in 1995.

Strain rate

Strain rate, also called rate of strain, is the rate at which a material deforms, defined as the time derivative of strain and measured in reciprocal seconds (s⁻¹).

Strain rate imaging

Strain rate imaging measures the speed of myocardial deformation (s^-1) by tissue Doppler or speckle-tracking echocardiography; distinguishes active contraction from tethering, standardized by ASE/EACVI, used for prognosis in heart disease.

Strain tensor

The strain tensor is a second-rank tensor of continuum mechanics that describes local deformation of a material body, with rigid-body motion removed; Augustin-Louis Cauchy set it out in 1822.

Strain theory (sociology)

Strain theory (sociology): criminological tradition from Merton's 1938 anomie theory to Agnew's 1992 general strain theory, explaining crime as a response to blocked goals, loss of valued stimuli, and negative stimuli.

Strain-mediated magnetoelectric control with PMN-PT

Strain-mediated magnetoelectric control with PMN-PT is a technique in which voltage-induced strain in the PMN-PT piezoelectric crystal alters an adjacent magnetic layer, enabling low-power spintronic devices.

Strain-promoted azide–alkyne cycloaddition

Strain-promoted azide–alkyne cycloaddition (SPAAC) is a copper-free click reaction between an organic azide and a strained cyclooctyne, used for labeling biomolecules on living cells and in antibody–drug conjugates.

Strain-promoted cycloaddition

Strain-promoted cycloaddition is a family of copper-free bioorthogonal reactions in which a strained alkyne, most often a cyclooctyne, reacts with an azide or diene, the release of ring strain driving the reaction.

Strain-release

Strain-release is a strategy in organic synthesis that uses the stored energy of strained rings, such as cyclopropanes and cyclobutanes, to drive carbon–carbon bond cleavage and ring opening.

Strain-release chemistry

Strain-release chemistry is a branch of organic synthesis in which the stored energy of strained small rings drives bond-forming reactions under mild conditions, widely used in drug discovery.

Strain-release functionalization

Strain-release functionalization is a strategy in organic synthesis where the stored strain energy of a small-ring compound, chiefly bicyclo[1.1.0]butane, drives new bond formation under mild conditions.

Strain-release functionalization of bicyclobutanes

Strain-release functionalization of bicyclobutanes is a set of synthetic methods in which bicyclo[1.1.0]butanes' strained central C–C bond is cleaved, yielding functionalized cyclobutanes, bridged bicyclics, and heterocycles under mild conditions.

Strained germanium channel transistor

A strained germanium channel transistor is a MOSFET with a compressively strained germanium channel, boosting hole mobility up to 4 to 25 times for high-performance CMOS.

Strained silicon

Strained silicon is silicon whose lattice is deliberately stretched, usually by growing it on silicon-germanium, raising carrier mobility; Intel commercialized it in its 90 nm process in 2003.