All articles starting with D
24,034 articles
Dual-Axis Radiographic Hydrodynamic Test Facility
The Dual-Axis Radiographic Hydrodynamic Test (DARHT) Facility at Los Alamos National Laboratory uses two perpendicular X-ray accelerators to image imploding mock nuclear weapon pits for stockpile stewardship.
Dual-clutch transmission
A dual-clutch transmission (DCT), also called a twin-clutch gearbox, is an automotive gearbox combining manual-transmission efficiency with automatic shift comfort, pre-selecting the next gear on a second clutch so shifts occur without traction interruption.
Dual-comb spectroscopy
Dual-comb spectroscopy is an optical technique that measures a sample's absorption and phase spectrum across a broad bandwidth by interfering two frequency combs whose repetition rates differ slightly.
Dual-cycle hydrocarbon pool mechanism
The dual-cycle hydrocarbon pool mechanism describes how acid zeolite catalysts convert methanol into hydrocarbons through two interlinked cycles, one based on olefins and one on aromatics.
Dual-die and multi-die stacking
Dual-die and multi-die stacking is a semiconductor approach bonding dies or wafers vertically with through-silicon vias into 3D integrated circuits, best known for high-bandwidth memory and 3D NAND flash.
Dual-energy computed tomography
Dual-energy computed tomography (DECT) acquires CT data at two X-ray energy spectra to characterize tissue composition, yielding iodine maps, virtual non-contrast images, and virtual monoenergetic images.
Dual-energy X-ray absorptiometry
Dual-energy X-ray absorptiometry (DXA, DEXA) is the standard imaging method for measuring bone mineral density using two X-ray energy peaks, diagnosing osteoporosis with a T-score of -2.5 or less, and monitoring treatment.
Dual-fuel combustion
Dual-fuel combustion is an engine method where a small diesel pilot ignites a premixed gaseous fuel such as natural gas, used widely in marine propulsion.
Dual-ion battery
A dual-ion battery is a rechargeable battery in which both electrolyte cations and anions intercalate into the electrodes, unlike the rocking-chair mechanism of lithium-ion cells.
Dual-mass flywheel
A dual-mass flywheel is a vehicle flywheel split into two masses connected by springs to filter engine vibration, developed by LuK and mass-produced from around 1985.
Dual-mode ramjet
A dual-mode ramjet, also called a dual-mode scramjet (DMS), is an air-breathing jet engine that runs with either subsonic or supersonic combustion, covering flight from about Mach 2 to beyond Mach 15.
Dual-phase steel
Dual-phase steel is an advanced high-strength steel with hard martensite islands in a soft ferrite matrix, giving high strength with good ductility for automotive parts.
Dual-phase titanium alloys
Dual-phase titanium alloys, usually called α + β titanium alloys, contain both the hexagonal α phase and the body-centered cubic β phase in their microstructure.
Dual-polarization 64-QAM
Dual-polarization 64-QAM (DP-64QAM, also written PDM-64QAM) is a coherent optical modulation format that transmits 64-state QAM on two polarizations, carrying 12 bits per symbol and reaching about 100 km.
Dual-porosity model
The dual-porosity model is a mathematical representation of a fractured porous medium treating rock as two overlapping continua, fractures and porous matrix, introduced by Barenblatt and colleagues in 1960.
Dual-probe in situ hybridization
Dual-probe in situ hybridization is a molecular pathology assay that counts HER2 gene and chromosome 17 signals in the same tumor cell nuclei to detect HER2 amplification in breast cancer.
Dual-rail qubit
A dual-rail erasure qubit is a quantum bit encoded in one photon shared between two modes, so photon loss becomes a detectable erasure that improves error correction.
Dual-source co-evaporation of perovskite
Dual-source co-evaporation of perovskite is a vacuum deposition method that forms perovskite thin films by evaporating two precursors simultaneously, used mainly for perovskite/silicon tandem solar cells.
Dual-source computed tomography
Dual-source computed tomography (DSCT) is a CT technique using two X-ray tubes and detectors mounted 90° apart on one gantry, giving fast cardiac imaging and dual-energy material analysis.
Dual-specificity phosphatase
Dual-specificity phosphatases (DUSPs, MKPs) are Cys-based protein tyrosine phosphatases with an HCX5R motif that dephosphorylate both phosphotyrosine and phosphoserine/threonine, chiefly inactivating MAPKs (ERK, JNK, p38); 10 mammalian MKPs in three localization-based subgroups regulate immunity, metabolism, cancer, and development.
Dual-sport motorcycle
A dual-sport motorcycle, also called dual-purpose or all-road, is a street-legal motorcycle usable both on pavement and off-road, typically with a 250 to 650cc single-cylinder engine.
Dual-task paradigm
The dual-task paradigm is an experimental method in cognitive psychology in which participants perform two tasks at once, so attentional resources and cognitive load can be measured.
Dual-threat quarterback
Dual-threat quarterback: an American football quarterback effective at both passing and rushing. Contrasted with pocket passers; central to spread option and read-option offenses; injury risk is the main concern.
Dual-track price system
The dual-track price system was China's reform letting the same goods sell at both planned and market prices, first proposed by economist Zhang Weiying in 1984 and abolished by 1992.
Dual-tree complex wavelet transform
The dual-tree complex wavelet transform (DTCWT), introduced by N.G. Kingsbury in 1998, runs two real wavelet transforms in parallel, giving near shift invariance and six directional subbands in 2-D.
DualDisc
DualDisc is a two-sided music disc introduced by major record labels in 2004, pairing a CD album with DVD-Audio, videos, and other DVD content on one disc.
Dualism
Dualism is the philosophy of mind theory that mind and body are fundamentally different kinds of things, most famously advanced by Descartes in his Meditations of 1641.
Dualite
Dualite is a rare yellow zircono-titanosilicate mineral of the eudialyte group, approved by the International Mineralogical Association in 2005 and found at Mount Alluaiv, Russia.
Duality (optimization)
Duality in optimization, notably Lagrangian duality, pairs a primal minimization problem with a dual maximization problem whose value bounds the primal and usually equals it for convex problems.
Dualizing sheaf
The dualizing sheaf is a coherent sheaf on a Noetherian scheme representing duality on coherent sheaves, generalizing the canonical bundle to singular spaces and underlying Serre and Grothendieck duality.