All articles starting with S
44,216 articles
Selective emitter solar cell
A selective emitter solar cell is a crystalline silicon solar cell whose front emitter is doped non-uniformly: heavily under the metal contacts and lightly between them, improving efficiency.
Selective epitaxial growth
Selective epitaxial growth (SEG) is a crystal growth technique that deposits a single-crystal semiconductor layer only through open windows in a mask, used in CMOS for raised and embedded source and drain regions.
Selective flotation
Selective flotation is a mineral processing method that separates valuable particles from waste gangue in an aerated slurry, using air bubbles that adhere only to water-repellent particles.
Selective harmonic elimination
Selective harmonic elimination (SHE), also called programmed PWM, is a technique for power converters whose precomputed switching angles eliminate chosen low-order harmonics, suiting high-power applications.
Selective hydrogenation
Selective hydrogenation is the catalytic addition of hydrogen to one type of unsaturated bond in a molecule while leaving other reducible groups untouched, used in petrochemical purification.
Selective IgM deficiency
Selective IgM deficiency (SIgMD) is a rare primary immunodeficiency, first described in 1967, in which serum IgM is absent or low while other antibody levels are normal.
Selective inference
Selective inference is a statistical framework for p-values and confidence intervals that stay valid when the hypothesis or model tested was chosen from the same data used to test it.
Selective internal radiation therapy
Selective internal radiation therapy (SIRT), also called radioembolization, is a liver-directed cancer treatment that injects radioactive microspheres into arteries feeding liver tumors, sparing normal liver.
Selective intrauterine growth restriction
Selective intrauterine growth restriction (sIUGR, or sFGR) is one fetus growing restrictively in a twin pregnancy, affecting 10–25% of monochorionic twins; classified Gratacós Types I–III by umbilical artery Doppler, with type-dependent mortality and management.
Selective ion sieving through graphene oxide membranes
Selective ion sieving through graphene oxide membranes is the water-driven transport effect reported at Manchester in 2012, in which graphene oxide sheets block solutes larger than about 4.5 Å.
Selective laser melting
Selective laser melting (SLM), also called laser powder bed fusion, is a metal additive manufacturing process that builds fully dense parts layer by layer from a laser-melted powder bed.
Selective laser sintering
Selective laser sintering, also known as laser sintering, is an additive manufacturing process that builds parts from a powder bed with a laser; it was invented in the mid-1980s at the University of Texas at Austin.
Selective leaching
Selective leaching, also called dealloying, is a corrosion process in which the most active element of an alloy dissolves, leaving a porous noble metal used to make nanoporous materials.
Selective methanation
Selective methanation (SMET) is a catalytic process that removes trace carbon monoxide from hydrogen-rich reformate by converting it to methane, serving as the final purification step before fuel cells.
Selective mutism
Selective mutism is a childhood anxiety disorder (DSM-5-TR, ICD-11; formerly elective mutism) in which a child speaks in some settings but consistently cannot speak where expected, such as school; onset ages 3–6, prevalence 0.2–1.6%, treated with CBT and SSRIs.
Selective neck dissection
Selective neck dissection is a head and neck surgery procedure removing only the cervical lymph node levels at risk of metastasis while preserving nerves and vessels.
Selective non-catalytic reduction
Selective non-catalytic reduction (SNCR) is a flue gas treatment that injects ammonia or urea into combustion exhaust, reducing nitrogen oxides to nitrogen and water without a catalyst.
Selective organ targeting (SORT) of lipid nanoparticles
Selective organ targeting (SORT) is a lipid nanoparticle engineering strategy that redirects mRNA and CRISPR delivery from the liver to organs like the lungs and spleen.
Selective plane illumination microscopy
Selective plane illumination microscopy (SPIM) is a light-sheet fluorescence microscopy method that illuminates a thin plane of a specimen from the side, enabling fast 3D imaging of living embryos.
Selective precipitation
Selective precipitation is a separation method that drives a chosen ion or protein out of solution as a solid while related species stay dissolved, by controlling pH or precipitant.
Selective reduction
Selective reduction is an obstetric procedure that terminates one or more fetuses in a multifetal pregnancy, usually by ultrasound-guided potassium chloride injection, to improve survival of the rest.
Selective search
Selective search is a region proposal algorithm for object recognition, introduced by Uijlings and colleagues in 2013, that generates class-independent candidate locations by hierarchically merging image regions, later serving as the proposal engine of R-CNN.
Selective serotonin reuptake inhibitor
Selective serotonin reuptake inhibitors (SSRIs) are antidepressants, including fluoxetine, sertraline, and escitalopram, that block the serotonin transporter SERT; first approved with fluoxetine (Prozac) in December 1987.
Selective Service Act of 1917
Selective Service Act of 1917, also the Selective Draft Act, was the US law signed by Wilson on May 18, 1917 creating the decentralized Selective Service System; 24.2 million registered, 2.8 million inducted for World War I.
Selective Service System
The Selective Service System, or U.S. Selective Service, is the independent federal agency that registers American men ages 18 through 26 for a potential military draft.
Selective thinning
Selective thinning is a forestry practice in which trees are removed or retained on their individual merits, providing more space, light, water, and nutrients for the best remaining trees.
Selective withdrawal
Selective withdrawal is the extraction of fluid from one chosen depth of a density-stratified body of fluid, most commonly water from a stratified reservoir through a multilevel outlet.
Selectivity coefficient
The selectivity coefficient, a potentiometric quantity, expresses how strongly an ion-selective electrode responds to an interfering ion relative to its primary ion; smaller values mean better selectivity.
Selectivity ratio
The selectivity ratio (SR) is a variable-importance measure in partial least squares regression that ranks predictors by explained over residual variance, introduced by Rajalahti and colleagues in 2008.
Selegiline
Selegiline (L-deprenyl, Jumex, EMSAM) is the first selective irreversible MAO-B inhibitor, developed by Joseph Knoll; used for Parkinson's disease and, as a transdermal patch, major depressive disorder.