42,772 articles
High-pressure NMR
High-pressure NMR is nuclear magnetic resonance spectroscopy performed on samples inside a diamond anvil cell at pressures up to 202 GPa, notably probing hydrogen in metal hydrides studied as high-temperature superconductors.
High-pressure X-ray diffraction
High-pressure X-ray diffraction is the measurement of X-ray diffraction patterns from crystalline samples under elevated pressure, usually in a diamond anvil cell, to determine structure, equation of state, and phase transitions.
High-purity germanium detector
A high-purity germanium (HPGe) detector is a semiconductor radiation detector, cooled with liquid nitrogen, that measures gamma-ray and X-ray energies with very high resolution; it succeeded the Ge(Li) detector.
High-redshift galaxy
A high-redshift galaxy is one whose light was emitted when the universe was young and stretched by expansion, studied mainly with Hubble and the James Webb Space Telescope.
High-redshift protocluster
A high-redshift protocluster is a concentration of galaxies and dark matter at an early cosmic epoch that is the progenitor of a present-day galaxy cluster, before the members collapse into one bound structure.
High-redshift quasar
A high-redshift quasar is a quasar, an active nucleus powered by a supermassive black hole, seen at redshift z above 6, within the Universe's first billion years.
High-resolution electron energy loss spectroscopy
High-resolution electron energy loss spectroscopy (HR-EELS), also known as vibrational electron energy loss spectroscopy, is an electron microscopy technique that detects vibrational excitations, phonons, and light elements such as hydrogen.
High-resolution mass spectrometry
High-resolution mass spectrometry (HRMS) is mass spectrometry using analyzers such as FT-ICR, Orbitrap, and time-of-flight that resolve closely spaced ion peaks and assign elemental compositions from accurate mass.
High-Resolution Rapid Refresh
The High-Resolution Rapid Refresh (HRRR) is a NOAA numerical weather prediction model that runs hourly at 3-km resolution across the United States, operational since 2014.
High-resolution resonant inelastic X-ray scattering
High-resolution resonant inelastic X-ray scattering (high-resolution RIXS) is an X-ray spectroscopy technique that measures the energy and momentum of excitations such as magnons and phonons with tens-of-millielectronvolt resolution.
High-resolution transmission electron microscopy
High-resolution transmission electron microscopy (HRTEM) is a technique that forms phase-contrast images of atomic lattices in thin specimens, used to study defects, interfaces, and nanoparticles in materials science.
High-resolution X-ray diffraction of epitaxial layers
High-resolution X-ray diffraction (HRXRD) is a branch of X-ray diffraction that uses highly monochromatic beams to measure composition, thickness, strain, relaxation, and defect broadening in single-crystalline epitaxial layers, an essential semiconductor characterization tool.
High-speed atomic force microscopy
High-speed atomic force microscopy (HS-AFM) is a scanning-probe technique that records nanoscale movies of biomolecules moving in liquid at video rate, first reported by Toshio Ando and colleagues in 2001.
High-temperature superconductivity
High-temperature superconductivity is superconductivity above roughly 30 K, begun by Bednorz and Müller's 1986 discovery in a copper oxide ceramic, honored with the 1987 Nobel Prize in Physics.
High-temperature superconductivity in pressurized La3Ni2O7
High-temperature superconductivity in pressurized La3Ni2O7 is a superconducting state with transition temperatures near 80 K in the bilayer nickelate La3Ni2O7 above 14 GPa, reported in 2023.
High-test peroxide
High-test peroxide (HTP), or high-test hydrogen peroxide, is concentrated hydrogen peroxide in water used as a rocket propellant, monopropellant, and storable oxidizer, in grades up to 98%.
High-throughput electrocatalyst screening
High-throughput electrocatalyst screening is the rapid, systematic evaluation of many candidate electrocatalyst materials in parallel to identify compositions with high activity and stability for reactions like hydrogen evolution and carbon dioxide reduction.
High-Z Supernova Search Team
The High-Z Supernova Search Team, led by Brian Schmidt, is an international collaboration whose 1998 observations of Type Ia supernovae revealed that the universe's expansion is accelerating.
Higher-dimensional class field theory
Higher-dimensional class field theory extends abelian class field theory to higher local fields and arithmetic schemes, due to Parshin and Kato, replacing the multiplicative group with Milnor K-groups.
Higher-dimensional supergravity
Higher-dimensional supergravity is supergravity formulated in spacetime dimensions above the four of ordinary general relativity; the eleven-dimensional theory of Cremmer, Julia, and Scherk (1978) is maximal and underlies M-theory.
Higher-energy collisional dissociation
Higher-energy collisional dissociation (HCD) is a fragmentation method in tandem mass spectrometry in which ions collide with gas in a dedicated cell; lacking CID's low-mass cutoff, it suits TMT quantification.
Higher-order aberration theory
Higher-order aberration theory describes optical wavefront errors by extending the aberration expansion beyond the five Seidel terms, adding fifth-, seventh-, and higher-order terms represented chiefly by Zernike polynomials.
Higher-order function
A higher-order function is a function that takes one or more functions as arguments, returns a function as its result, or both, as in map, filter, and fold.
Higher-order logic
Higher-order logic (HOL), also called simple type theory or Church's type theory, extends first-order logic by quantifying over predicates and functions via the simply typed lambda calculus; standard semantics is not axiomatizable, Henkin semantics is complete, and HOL underlies proof assistants like Isabelle/HOL and HOL Light.
Higher-order post-Newtonian effects
Higher-order post-Newtonian effects are corrections to Newtonian gravity and first-post-Newtonian relativity, covering 2PN through 4PN two-body dynamics, gravitational-wave tail terms, and the frontier at 5PN and 6PN.
Higher-order singular value decomposition
The higher-order singular value decomposition (HOSVD), also known as higher-order SVD, is a multilinear generalization of the matrix SVD, introduced by De Lathauwer, De Moor, and Vandewalle in 2000.
Higher-order topological insulator
A higher-order topological insulator (HOTI) is an insulating material whose surfaces are gapped but which hosts protected states at corners or hinges, predicted in 2017.
Higher-order topological insulator in bismuth
Bismuth is a higher-order topological insulator, a crystalline solid with insulating bulk and surfaces but conducting, topologically protected hinge modes, established in a 2018 Nature Physics study.
Highest temperature recorded on Earth
The highest temperature recorded on Earth is 56.7 °C (134 °F), measured at Furnace Creek Ranch in Death Valley, California, on 10 July 1913, though a 2025 reanalysis contests it.
Highest-weight theory
Highest-weight theory is the branch of representation theory classifying representations of semisimple Lie algebras and Lie groups by a single linear functional, the highest weight, attached to each irreducible representation.