42,772 articles
Ellipsometer
An ellipsometer is an optical instrument that measures the change in polarization of light upon specular reflection, used to determine film thicknesses, refractive indices, and other optical properties.
Ellipsometry
Ellipsometry is a nondestructive, contactless optical technique that measures how reflected light's polarization changes, fitting optical models to determine thin-film thickness, refractive index, roughness, and composition.
Elliptic curve
An elliptic curve is a smooth curve of genus one with a group law, given by y² = x³ + ax + b, used in modern cryptography.
Elliptic flow
Elliptic flow is the second harmonic coefficient (v2) of particle emission in noncentral heavy-ion collisions, the principal signature of fluid-like behavior in the quark-gluon plasma.
Elliptic function
An elliptic function is a meromorphic function of a complex variable that is doubly periodic, with two periods whose ratio is not real; it arose from inverting elliptic integrals.
Elliptic integral
Elliptic integral is a special function, first studied by John Wallis in 1655 regarding the arc length of an ellipse. It is an integral involving cubic or quartic polynomials.
Elliptic partial differential equation
An elliptic partial differential equation, or elliptic PDE, is a PDE whose highest-order terms have no real characteristic directions, exemplified by the Laplace and Poisson equations governing steady-state physics.
Elliptical copula
An elliptical copula is the copula of an elliptically contoured distribution, capturing its dependence structure separately from its marginals; examples include the Gaussian and Student t copulas.
Elliptical distribution
An elliptical distribution is a multivariate probability distribution whose density is constant on ellipsoids centered at a location vector, generalizing the multivariate normal distribution and widely applied in statistics, econometrics, and financial risk modeling.
Elliptical galaxy
An elliptical galaxy is a smooth, oval-shaped galaxy of old, red stars orbiting in random directions, with little gas or dust and little ongoing star formation.
Elliptical polarization
Elliptical polarization is the most general polarization state of a transverse wave, in which the electric field vector traces an ellipse; linear and circular polarization are special cases.
Ellis Kolchin
Ellis Kolchin (1916–1991) was an American mathematician at Columbia University, pupil and successor of Joseph Fels Ritt, who shaped differential algebra and created differential algebraic groups.
Ellis L. Johnson
Ellis L. Johnson (1938–2024) was an operations research mathematician known for foundational work in integer programming, who spent 25 years at IBM and later held a chaired professorship at Georgia Tech.
Ellyn Enderlin
Ellyn Enderlin is an American glaciologist and Associate Professor of Geosciences at Boise State University in Idaho, known for measuring how glaciers change using satellite datasets.
Elmar Thoma
Elmar Thoma (1926–2002) was a German mathematician who worked in harmonic analysis and representation theory, known for Thoma's theorem on countable discrete groups of type I.
Elmer Keiser Bolton
Elmer Keiser Bolton (1886–1968) was an American organic chemist who directed DuPont's Chemical Department from 1930 to 1951, directing the research organizations that produced neoprene, nylon, and Teflon.
Elmer McCollum
Elmer McCollum (1879–1967) was an American biochemist who discovered vitamin A, helped establish the alphabetical naming of vitamins, and pioneered rat-based nutrition research at Wisconsin and Johns Hopkins.
Elmer Peter Kohler
Elmer Peter Kohler (1865–1938) was an American organic chemist and Harvard professor known for work on unsaturated compounds, including the first resolution of an allene.
Elon Lindenstrauss
Elon Lindenstrauss, born 1970, is an Israeli mathematician working in ergodic theory, dynamical systems, and number theory, and the first Israeli Fields Medalist, winning in 2010.
Elsa M. Garmire
Elsa M. Garmire, born 1939, is an American physicist known for nonlinear optics and semiconductor lasers, elected to the National Academy of Engineering in 1989.
Elsie M. Sunderland
Elsie M. Sunderland is a Canadian-American environmental chemist, the Fred Kavli Professor at Harvard since 2022, whose research on methylmercury and PFAS has shaped US mercury regulation.
Elso S. Barghoorn
Elso S. Barghoorn (1915–1984) was an American paleobotanist at Harvard University who founded the formal field of Precambrian paleobiology, the study of life recorded in rocks older than the well-preserved fossil record.
Elspeth Garman
Elspeth Garman, born 1954, is a British molecular biophysicist and Oxford professor known for the "Garman limit" radiation dose limit and for making cryo-cooling of protein crystals routine.
Eltrombopag
Eltrombopag, sold as Promacta and Revolade, is an oral drug that stimulates platelet production and treats thrombocytopenia in immune thrombocytopenia, hepatitis C, and aplastic anemia.
Elution
Elution is the washing of adsorbed solutes off a chromatographic stationary phase by the mobile phase, the eluent, producing separated bands that a detector records as peaks.
Elutriation
Elutriation is a separation technique sorting particles suspended in a fluid by size using an upward or inward flow opposing sedimentation, used to isolate live cell populations.
Elwyn Berlekamp
Elwyn Ralph Berlekamp (1940–2019) was an American mathematician and electrical engineer at UC Berkeley, known for the Berlekamp–Massey algorithm for decoding Reed–Solomon codes and for combinatorial game theory.
EM-DAT
EM-DAT, the Emergency Events Database, is a free global database of disasters and their human and economic impacts from 1900 to the present, maintained by CRED at UCLouvain in Brussels.
Emanuel R. Piore
Emanuel R. Piore (1908–2000) was an American physicist and research administrator who led science at the Office of Naval Research and then IBM, helping develop digital computers.
Emanuel Sperner
Emanuel Sperner (1905–1980) was a German mathematician who, as a 22-year-old student, proved Sperner's theorem on antichains and Sperner's lemma, the combinatorial backbone of proofs of Brouwer's fixed-point theorem.