42,772 articles
Nilsson model
The Nilsson model is a nuclear shell model describing nucleons in an axially deformed harmonic-oscillator potential, formulated by Sven Gösta Nilsson in his 1955 paper.
Nilsystem
A nilsystem is a dynamical system on a compact nilmanifold G/Γ of a nilpotent Lie group, with translation dynamics; nilsystems are the characteristic factors in multiple ergodic averages.
Nima Arkani-Hamed
Nima Arkani-Hamed, born 1972, is a Canadian-American theoretical particle physicist at the Institute for Advanced Study in Princeton, known for large extra dimensions, split supersymmetry, and the amplituhedron.
Nimber
A nimber, also called a Grundy value or nim-value, is the value assigned to a position in an impartial combinatorial game; a nonzero nimber means a winning position.
Nimbostratus cloud
Nimbostratus is a gray, often dark cloud layer, diffuse because of continuously falling rain or snow, that forms mainly from thickening altostratus along warm fronts of mid-latitude cyclones.
Nimrod Moiseyev
Nimrod Moiseyev (N. Moiseyev) is an Israeli theoretical chemist and Professor Emeritus at Technion who developed non-Hermitian quantum mechanics and authored the first textbook on the subject.
Nineteenth-century classical physics
Nineteenth-century classical physics is the body of physical theory developed from about 1800 to the 1890s, including energy conservation, the wave theory of light, and Maxwell's electromagnetic synthesis.
Ning Zeng
Ning Zeng is a climate and carbon-cycle scientist at the University of Maryland, known for proposing wood vaulting, a carbon removal method based on burying wood.
Ninhydrin
Ninhydrin is an organic compound that reacts with amino acids to give a purple dye and is widely used to detect amino acids and develop latent fingerprints.
Nintedanib
Nintedanib, sold as Ofev and Vargatef, is an oral tyrosine kinase inhibitor developed by Boehringer Ingelheim, first FDA-approved in 2014 to slow lung function decline in idiopathic pulmonary fibrosis.
Niobium
Niobium, symbol Nb and atomic number 41, is a corrosion-resistant transition metal used chiefly to strengthen steel and in superconducting magnets for MRI scanners and accelerators.
Niobium alloys
Niobium alloys are metallic alloys based on niobium, a refractory metal with a melting point of 2477 °C, used in rocket nozzles, jet engines, superconductors, and medical implants.
Niobium arsenide
Niobium arsenide (NbAs) is an inorganic compound of niobium and arsenic, crystallizing in a noncentrosymmetric tetragonal structure and confirmed in 2015-era experiments as one of the first Weyl semimetals.
Niobium carbide
Niobium carbide (NbC) is an extremely hard refractory ceramic compound of niobium and carbon with a melting point of 3,520 °C, used in tool steels and cemented carbides.
Niobium diselenide
NbSe2, or niobium diselenide, is a layered transition-metal dichalcogenide combining superconductivity with a 3×3 charge-density wave; bulk crystals superconduct below 7.2 K, and atomically thin layers show Ising superconductivity.
Niobium nitride
Niobium nitride (NbN) is a superconducting compound of niobium and nitrogen with a critical temperature of 14.7 to 16 K, making it the standard material for superconducting nanowire single-photon detectors.
Niobium oxide
Niobium oxide refers to compounds of niobium and oxygen, from NbO to Nb₂O₅ and mixed oxides, among the most studied fast-charging lithium-ion battery anode materials since the early 2010s.
Niobium pentoxide
Niobium pentoxide (Nb₂O₅), also called niobium(V) oxide, is a white, water-insoluble solid and the most stable compound of niobium, with over 15 crystalline phases and uses in lithium-ion batteries, optical glass, and capacitors.
Niobium–tin
Niobium–tin (Nb3Sn) is a superconducting intermetallic compound of niobium and tin, discovered in 1954 with a then-record 18 K transition temperature and used in high-field magnets for fusion reactors and particle accelerators.
Niobium–titanium
Niobium–titanium (NbTi) is a ductile alloy superconductor, typically 46–48 percent titanium, used in the magnets of the LHC, clinical MRI machines, and the ITER fusion reactor.
Niobrara Formation
The Niobrara Formation is a Late Cretaceous unit of chalk, limestone, and shale deposited in the Western Interior Seaway, named by Meek and Hayden in 1862.
NIP theory
NIP theory, also called a dependent theory, is a first-order theory in which no formula has the independence property. Introduced by Saharon Shelah, it is a central tameness dividing line in model theory.
NiPS3
NiPS3, or nickel phosphorus trisulfide, is a layered van der Waals antiferromagnetic semiconductor whose Ni spins order in a zigzag pattern below about 150 K.
NIR-II fluorescence imaging
NIR-II fluorescence imaging is an optical technique that visualizes biological structures, using contrast agents and InGaAs detectors to enable penetration with micrometre resolution in living animals.
Nirenberg and Matthaei experiment
The Nirenberg and Matthaei experiment was a 1961 NIH study showing that poly-U RNA directs phenylalanine synthesis, giving the first decoded word of the genetic code.
Nirit Dudovich
Nirit Dudovich (נירית דודוביץ) is an Israeli physicist at the Weizmann Institute of Science who studies attosecond science, measuring electron motion with ultra-short laser pulses.
NIRPS
NIRPS (Near Infra-Red Planet Searcher) is a high-resolution near-infrared spectrograph on the ESO 3.6-meter telescope at La Silla Observatory, Chile, built to discover exoplanets around red dwarf stars.
Nisan
Nisan (Hebrew: ניסן) is the first month of the Jewish ecclesiastical year and the seventh of the civil year in the Hebrew calendar, the month of Passover.
NIST Handbook 44
NIST Handbook 44, formally Specifications, Tolerances, and Other Technical Requirements for Weighing and Measuring Devices, is the annual US standard for commercial weighing and measuring equipment.
NIST-F1
NIST-F1 is a laser-cooled cesium fountain atomic clock at NIST in Boulder, Colorado, serving as the United States primary frequency standard from 1999 and defining the SI second.