42,772 articles
Orthonormal basis
An orthonormal basis, also called a complete orthonormal system, is a basis of an inner product space with unit-length, mutually orthogonal vectors, and it extends to Hilbert spaces.
Orthonormality
Orthonormality is the property of a set of vectors, such as an orthonormal basis, whose members are unit vectors and mutually orthogonal, with inner products given by the Kronecker delta.
Orthotropic material
An orthotropic material is a material with elastic properties differing along three mutually perpendicular axes, described by nine independent elastic constants; wood, composite laminates, and cortical bone are examples.
Ortwin Hess
Ortwin Hess is a theoretical physicist working in quantum nanophotonics and metamaterials at Trinity College Dublin, known for the 2007 trapped rainbow principle and the Royal Society's Rumford Medal.
Orville Frank Tuttle
Orville Frank Tuttle (1916–1983) was an American experimental petrologist who showed that granite forms from a water-bearing melt and designed the Tuttle bomb pressure vessel.
Orville L. Chapman
Orville L. Chapman, born Orville Lamar Chapman (1932–2004), was an American organic chemist and UCLA professor who pioneered low-temperature trapping of reactive intermediates and synthesized carpanone in one step.
Osamu Ishitani
Osamu Ishitani (石谷治) is a Japanese photochemist known for rhenium and ruthenium–rhenium photocatalysts that convert carbon dioxide to carbon monoxide or formic acid, and a professor at Hiroshima University.
Osamu Sato
Osamu Sato (佐藤 治) is a Japanese materials and coordination chemist, a professor at Kyushu University known for photomagnetism, spin crossover, and dynamic molecular crystals, and for his 1996 Science paper on photoinduced magnetization.
Osamu Terasaki
Osamu Terasaki is a Japanese electron crystallographer known for solving the atomic structures of zeolites, mesoporous materials, and metal-organic frameworks by electron microscopy, with careers at Tohoku and Stockholm universities.
Oscar K. Rice
Oscar Knefler Rice (1903–1978) was an American physical chemist at the University of North Carolina, elected to the National Academy of Sciences in 1964, known for unimolecular reaction theory.
Oscar Loew
Oscar Loew (1844–1941) was a German agricultural chemist who announced catalase in 1900, discovered manganese as a plant nutrient, and taught in Tokyo and Munich.
Oscar Randal-Williams
Oscar Randal-Williams is a mathematician at the University of Cambridge, the Sadleirian Professor of Pure Mathematics, known for work on moduli spaces of manifolds with Søren Galatius.
Oscar Schlömilch
Oscar Schlömilch (1823–1901) was a German mathematician, professor in Dresden, founding editor of the Zeitschrift für Mathematik und Physik, and namesake of the Schlömilch series, an 1857 expansion in Bessel functions.
Oscar W. Greenberg
Oscar W. Greenberg is an American physicist who in 1964 introduced the three-valued quark charge now called color, resolving the spin-statistics paradox and providing an ingredient of quantum chromodynamics.
Oscar Zariski
Oscar Zariski, born Asher Zaritsky, was an American mathematician who rebuilt the foundations of algebraic geometry on commutative algebra, teaching at Johns Hopkins and then Harvard until 1969.
Oscillation
Oscillation is back-and-forth motion about an equilibrium position repeated at regular intervals; its study underlies waves, pendulum clocks, resonance, and examples from swings to vibrating atoms.
Oscillator strength
Oscillator strength, also called the f value, is a dimensionless measure of the strength of an allowed radiative transition between two quantum states of an atom, ion, or molecule.
Oscillatory shear rheometry
Oscillatory shear rheometry is a measurement technique that applies sinusoidally varying shear deformation and analyzes the stress response to determine viscoelastic properties, the standard method for polymer melts, gels, and soft solids.
Oscilloscope
An oscilloscope, often called an o-scope, is an electronic test instrument that displays how a voltage varies over time, drawing the waveform as a graph.
Osisko Development Corp.
Osisko Development Corp., formerly Ringbolt Ventures Ltd., is a Canadian gold development company incorporated in 2006, holding the Cariboo Gold Project in British Columbia and the Tintic Project in Utah.
Oskar Backlund
Oskar Backlund, known in Russia as Oskar Andreevich Baklund, was a Swedish-born astronomer who directed the Pulkovo Observatory from 1895 to 1916 and studied Encke's comet.
Oskar Bolza
Oskar Bolza (1857–1942) was a German mathematician known for the problem of Bolza in the calculus of variations, who taught at the University of Chicago from 1892 to 1910.
Oskar Klein
Oskar Benjamin Klein (1894–1977) was a Swedish theoretical physicist and longtime collaborator of Niels Bohr, known for the Klein–Gordon equation, Kaluza–Klein theory, and the Klein–Nishina formula.
Oskar Painter
Oskar Painter, born 1972, is an experimental physicist and Caltech professor known for optomechanical crystals, who since December 2019 has directed quantum hardware at Amazon Web Services.
Oskar Perron
Oskar Perron (1880–1975) was a German mathematician who held chairs at Heidelberg and Munich and is known for the Perron–Frobenius theorem, the Perron integral, and continued fractions.
Oskar Wintersteiner
Oskar Wintersteiner (1898–1971) was an Austrian-American biochemist who first crystallized penicillin and showed it contained sulfur, and who isolated progesterone and helped isolate cortisone at Squibb.
Oslo method
The Oslo method, developed at the Oslo Cyclotron Laboratory in Norway, extracts the nuclear level density and γ-ray strength function from particle-γ coincidence data, feeding neutron-capture calculations for astrophysics and reactors.
Osmium
Osmium is a hard, bluish-silver platinum-group metal, atomic number 76, often cited as the densest element, discovered in 1803 and known for its very toxic tetroxide and hard, wear-resistant alloys.
Osmium tetroxide
Osmium tetroxide (OsO4), also called osmic acid, is a volatile, highly poisonous oxide of osmium used as a fixative and stain in electron microscopy and as a reagent for cis-dihydroxylation of alkenes.
Osmometry
Osmometry is a family of analytical techniques that measure the osmotic pressure or osmolality of a solution, using vapor pressure, freezing point, or membrane methods to determine solute concentration and molecular weight.