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Nuclear Overhauser effect spectroscopy
Nuclear Overhauser effect spectroscopy (NOESY) is a two-dimensional NMR experiment measuring cross-relaxation between spatially close nuclei, introduced in 1980 and used to determine protein and small-molecule structures.
Nuclear pairing
Nuclear pairing is the correlation in which two nucleons couple to zero angular momentum, giving open-shell nuclei superfluid properties; it explains odd-even binding-energy staggering and neutron-star superfluidity.
Nuclear pasta
Nuclear pasta is a phase of matter in neutron star crusts where nuclei form rod-like and slab-like shapes; simulations suggest it may be the strongest known material.
Nuclear physics
Nuclear physics is the branch of physics that studies atomic nuclei, their protons and neutrons, the strong force that binds them, and their reactions and decays.
Nuclear quadrupole resonance
Nuclear quadrupole resonance (NQR) is a radio-frequency spectroscopic technique for rigid solids, related to NMR but requiring no external magnetic field, first observed in 1949.
Nuclear quadrupole resonance spectroscopy
Nuclear quadrupole resonance (NQR) spectroscopy is a radio-frequency technique for solids, often called zero-field NMR, discovered in 1949 and used to detect explosives, narcotics, and landmines, and to analyze pharmaceuticals.
Nuclear quantum effects in water
Nuclear quantum effects in water arise from zero-point energy, delocalization, and tunneling of protons, measurably altering the structure, dynamics, and spectroscopy of liquid water, ice, and aqueous interfaces.
Nuclear reaction
A nuclear reaction, also called a nuclear process, occurs when an incoming particle such as a proton, neutron, or alpha particle collides with an atomic nucleus and produces different nuclei.
Nuclear reaction analysis
Nuclear reaction analysis (NRA) is an ion beam analysis method that directs MeV ions at a solid and detects nuclear reaction products to profile light elements like hydrogen and lithium.
Nuclear resonance
A nuclear resonance is a quasi-stationary energy level of a compound nucleus that appears as a sharp peak in the reaction cross section at discrete projectile energies.
Nuclear resonance scattering
Nuclear resonance scattering (NRS) is a family of X-ray spectroscopy techniques in which synchrotron radiation excites narrow nuclear resonances in Mössbauer isotopes, first demonstrated at Hamburg in 1985.
Nuclear rotation
Nuclear rotation is the collective, quantized rotation of an atomic nucleus as a whole, occurring in deformed nuclei such as the rare-earth (mass 150–190) and actinide regions.
Nuclear scattering theory
Nuclear scattering theory is the framework describing elastic and inelastic scattering of neutrons and protons by nuclei, built on partial-wave analysis, phase shifts, and the optical model.
Nuclear Schiff moment
The nuclear Schiff moment is a T,P-violating electric moment of a nucleus, the leading observable one in neutral atoms, and the key nuclear input to atomic EDM searches.
Nuclear Science Laboratory (University of Notre Dame)
The Nuclear Science Laboratory is a low-energy nuclear physics facility at the University of Notre Dame, operating three on-campus particle accelerators since the late 1930s.
Nuclear shell model
The nuclear shell model describes how protons and neutrons occupy shells in the atomic nucleus, explaining the magic numbers 2 through 126 and nuclear stability.
Nuclear space
A nuclear space, introduced by Grothendieck in 1955, is a locally convex space in which every continuous linear map into a Banach space is a nuclear operator.
Nuclear spin
Nuclear spin is the quantum number I measuring an atomic nucleus's total angular momentum; even-even nuclei have spin 0, and nonzero spin enables magnetic resonance.
Nuclear spin and parity
Nuclear spin and parity are quantum properties of an atomic nucleus. Odd mass number gives half-integer spin, even mass number gives integer spin, and every measured even-even nucleus has ground state 0+.
Nuclear strikes on hurricanes
Nuclear strikes on hurricanes, also called nuking a hurricane, is a recurring proposal to destroy hurricanes with bombs, rejected by scientists as ineffective and a radioactive fallout hazard.
Nuclear technology
Nuclear technology is the body of techniques using nuclear reactions, chiefly fission, fusion, and radioactivity, for electricity generation, medicine, industry, agriculture, and research, coordinated internationally by the IAEA.
Nuclear transmutation
Nuclear transmutation, also known as transmutation of elements, is the conversion of one chemical element or isotope into another through nuclear reactions, studied for reducing long-lived radioactive waste.
Nuclear winter
Nuclear winter is the hypothesized severe cooling and darkness that would follow nuclear war, first modeled in a 1983 paper by Turco, Toon, and Sagan's colleagues.
Nucleate boiling
Nucleate boiling is a boiling mode in which vapor bubbles grow at nucleation sites on a heated surface and detach, the most efficient boiling regime for heat transfer.
Nucleation
Nucleation, or the nucleation point, is the first step of phase transformations such as condensation, solidification, and crystallization, where rare fluctuations overcome a surface-energy barrier.
Nucleation overpotential
Nucleation overpotential (ηn) is the extra electrode potential, beyond the thermodynamic deposition potential, required to form stable metal nuclei during electroplating, appearing as a voltage spike at the onset of lithium deposition.
Nucleic acid double helix
The nucleic acid double helix, known as the DNA double helix or Watson-Crick structure, is the paired spiral of DNA or RNA strands, described by Watson and Crick in 1953.
Nucleic acid structure
Nucleic acid structure is the organization of DNA and RNA molecules across four levels, from nucleotide sequence and base pairing to 3D folding and interactions with proteins or other nucleic acids.
Nucleon
A nucleon is a proton or neutron, the two baryons that make up atomic nuclei, each built from three quarks and treated as two states of one particle.
Nucleophile
A nucleophile is a chemical species that donates an electron pair to bond with an electron-poor electrophile, playing a central role in organic substitution reactions.