42,772 articles
Epistemic modal logic
Epistemic modal logic, also called epistemic logic, is the branch of modal logic that formalizes knowledge and belief with operators like "agent a knows that". Jaakko Hintikka's 1962 book founded the field.
Epistemic network analysis
Epistemic network analysis (ENA) is a quantitative discourse analysis method modeling connections among coded elements as weighted networks, introduced by David Williamson Shaffer in 2009.
Epistemic values
Epistemic values are properties of a scientific hypothesis or theory, such as accuracy, consistency, scope, simplicity, and fruitfulness, that guide the assessment and choice of theories.
Epistemological break
The epistemological break (French rupture épistémologique) is a philosophy of science concept introduced by Gaston Bachelard in the 1930s, holding that science must break with everyday common sense rather than refine it.
Episulfide
An episulfide (thiirane, olefin sulfide) is a strained, reactive three-membered cyclic sulfide, the sulfur analog of an epoxide, used in organic synthesis and as a monomer for polythioether polymers.
Epitaxial graphene
Epitaxial graphene is graphene grown directly on a silicon carbide wafer by heating it so silicon sublimes and carbon rearranges into hexagonal layers, without any transfer step.
Epitaxially connected quantum dot superlattices
Epitaxially connected quantum dot superlattices are ordered arrays of colloidal semiconductor nanocrystals fused by direct crystal-to-crystal atomic bonding, enabling strong electronic coupling and band-like charge transport.
Epoch (astronomy)
In astronomy, an epoch is a specific instant chosen as a reference for measurements or coordinate systems, since star positions and orbits change over time.
Epoch (computing)
An epoch in computing is a fixed reference date from which a system counts elapsed time; the best-known is the Unix epoch, 00:00:00 UTC on 1 January 1970.
EPOS (research infrastructure)
EPOS (the European Plate Observing System) is a distributed European research infrastructure integrating solid Earth science data and services, established as a consortium with its seat in Rome in 2018.
Epoxidation
Epoxidation is the chemical conversion of an alkene into an epoxide, a three-membered cyclic ether, by adding a single oxygen atom across the carbon–carbon double bond.
Epoxide
An epoxide, also known as an oxirane, is a cyclic ether with one oxygen and two carbon atoms in a strained three-membered ring, making it a key building block in organic synthesis and epoxy resins.
Epoxide ring-opening reactions
Epoxide ring-opening reactions are nucleophilic cleavages of the strained three-membered epoxide ring that release about 27 kcal/mol of strain and yield diols, halohydrins, or amino alcohols.
Epoxide–anhydride ring-opening copolymerization
Epoxide–anhydride ring-opening copolymerization (ROCOP) is a chain-growth polymerization in which an epoxide and a cyclic anhydride react in alternation, yielding degradable, often fully alternating polyesters from commercialized monomers.
Epoxy
Epoxy, also called epoxy resin or polyepoxide, is a thermosetting polymer cured with hardeners such as amines into strong cross-linked networks, used widely in adhesives and coatings.
Eppendorf tube
An Eppendorf tube is a small single-use polypropylene microcentrifuge tube, typically holding 0.5 to 2 mL, used in laboratories to mix, store, and centrifuge microliter-scale samples.
EPR paradox
The EPR paradox is a 1935 argument by Einstein, Podolsky, and Rosen that, if locality holds, quantum mechanics is incomplete; Bohr replied, and Bell later reconsidered it.
EPR steering
EPR steering, also called quantum steering, is a form of quantum nonlocality where measuring one half of an entangled state remotely prepares the other half's states.
EPS Conference on Plasma Physics and Fusion
The EPS Conference on Plasma Physics and Fusion is the annual flagship meeting of the European Physical Society's Plasma Physics Division, first held in Munich in 1966.
EPS Europhysics Prize
The EPS Europhysics Prize, also known as the Europhysics Condensed Matter Prize, is a biennial European prize for discoveries in condensed matter physics, awarded since 1975.
Epsilon Aurigae
Epsilon Aurigae is an eclipsing binary star in the constellation Auriga, where a visible F-type supergiant fades every 27.1 years behind an opaque disk around a companion B star.
Epsilon Canis Majoris
Epsilon Canis Majoris, commonly called Adhara, is a binary star system in Canis Major and that constellation's second-brightest star, the brightest known extreme ultraviolet source beyond the Sun.
Epsilon Cygni
Epsilon Cygni, or Aljanah, is an orange giant star of magnitude 2.48 in the constellation Cygnus, forming the eastern wing of the Northern Cross about 75 light-years away.
Epsilon expansion
The epsilon expansion is a calculational method in critical phenomena that computes critical exponents as power series in ε = 4 − d, introduced by Kenneth Wilson in 1972.
Epsilon Fornacis
Epsilon Fornacis (HD 18907) is a spectroscopic binary star in the southern constellation Fornax, roughly 105 light years away, whose metal-poor primary is over 12 billion years old.
Epsilon Geminorum
Epsilon Geminorum, also called Mebsuta, is a yellow supergiant star in Gemini about 840 light-years away, best known as the target of a rare occultation by Mars in 1976.
Epsilon number
An epsilon number is a transfinite ordinal that is a fixed point of omega exponentiation, satisfying ω^α = α, with ε₀ the first and best known.
Epsilon Orionis
Epsilon Orionis, also known as Alnilam, is a blue supergiant forming the center of Orion's Belt, the brightest and most distant of the three belt stars.
Epsilon Pegasi
Epsilon Pegasi, or Enif, is an orange K-type supergiant about 690 light-years away marking the nose of the winged horse Pegasus, and the constellation's brightest star.
Epsilon Persei
Epsilon Persei, officially named Áldu since 2025, is a bright multiple star system in Perseus, a massive, rapidly rotating Beta Cephei variable about 638 light-years away.