按方法、领域与证据探索科学。

Acoustic Holography

Near-Field Acoustic Holography (NAH) is a technique for reconstructing 3D acoustic sound fields and visualizing sound radiation from sources by measuring pressure at a dense microphone array in the near field. Pioneered by Maynard, Williams, and Lee in 1985, NAH extends holographic principles from optics to acoustics,

nuclear physics

Criticality Safety Analysis

Criticality safety analysis is a systematic evaluation of fissile material systems to ensure nuclear chain reactions remain controlled, originating from Hahn and Strassmann's 1938 discovery of nuclear fission. It determines safe limits on fissile mass, concentration, geometry, and spacing using neutron transport calcul

applied physics

Gravity Assist

A gravity assist (or swing-by) maneuver uses the gravitational field of a planet or other celestial body to alter a spacecraft's trajectory and velocity without expending fuel. Discovered by Michael Minovitch at JPL in 1961, this technique is crucial for reaching distant planets economically. It works by exploiting the

optics

ABCD Matrix

The ABCD matrix, or ray transfer matrix method, is a compact algebraic framework for analyzing optical systems. Introduced by Kogelnik and Li in 1966, it represents the linear transformation of ray position and angle (or Gaussian beam parameters) through optical elements. This method is foundational in laser physics, G

oceanography

Acoustic Doppler Current Profiler

The Acoustic Doppler Current Profiler (ADCP) is an instrument that uses Doppler-shifted acoustic backscatter to measure water velocity profiles along a vertical profile. Developed by RD Instruments in the 1980s, it has become the standard method for high-resolution current profiling in oceanographic research. ADCPs pro

acoustics

Acoustic Ray Tracing

Acoustic ray tracing is a computational technique for predicting sound propagation in rooms by treating acoustic energy as rays that reflect specularly off surfaces. Formalized by Allen and Berkley in 1979 via the image source method, ray tracing is one of the most computationally efficient methods for room acoustic si

applied physics

Adsorption Isotherm (Langmuir-Freundlich)

Adsorption isotherms describe the equilibrium uptake of a substance on a solid surface as a function of gas or solution phase concentration at constant temperature. The Langmuir isotherm (1918) and Freundlich isotherm (1906) are classical empirical models. The Langmuir model assumes monolayer coverage and is mechanisti

geophysics

Aerosol Optical Depth

Aerosol Optical Depth (AOD) is a dimensionless measure of aerosol light extinction in the atmosphere, quantifying how much sunlight is scattered and absorbed by particles suspended in air. Formalized by Ångström in 1929 and now routinely measured via satellite (MODIS, Sentinel-5P) and ground networks (AERONET), AOD is

geophysics

Ambient Noise Tomography

Ambient Noise Tomography (ANT) is a seismic imaging method that extracts surface wave information from long-term records of seismic background noise, enabling high-resolution imaging of crustal and upper mantle structure. Developed by Shapiro, Campillo, and colleagues in 2005, ANT has revolutionized seismic imaging by

applied physics

Ambisonics

Ambisonics is a full-sphere spatial audio encoding and reproduction technique that captures and reproduces three-dimensional sound fields. Developed by Michael Gerzon in the 1970s, it uses spherical harmonics to represent sound at all directions around a central point. Unlike surround systems that use discrete channels

analytical chemistry

Analytical Method Validation

Analytical method validation is a systematic process of establishing documented evidence that an analytical method is suitable for its intended use in measuring the identity, purity, strength, and/or content of a substance. Governed by regulatory agencies (FDA, ICH) and industry standards (USP, EP), validation ensures

particle physics

Anti-kT Jet Algorithm

The anti-kT jet algorithm, introduced by Cacciari and Salam in 2008, is a sequential recombination jet clustering algorithm widely used in high-energy physics to group final-state particles into jets. Unlike earlier algorithms, anti-kT produces jets with regular cone-like geometries in transverse momentum-rapidity spac

astronomy

Asteroseismology

Asteroseismology is the study of stellar oscillations—tiny brightness and radial velocity variations caused by sound waves resonating inside stars. Proposed by Roger Ulrich in 1970 and established as a major field by the Kepler and TESS space telescopes, asteroseismology provides unprecedented precision in determining

astronomy

Astrometry (Parallax)

Astrometric parallax is the foundational geometric method for measuring distances to nearby stars, based on observing the apparent shift in a star's position as Earth orbits the Sun. First successfully demonstrated by Friedrich Wilhelm Bessel in 1838 for the star 61 Cygni, parallax remains the most direct and reliable

analytical chemistry

Atomic Absorption Spectroscopy

Atomic absorption spectroscopy is an analytical technique that measures the concentration of metal elements by detecting the absorption of light by ground-state metal atoms in the gaseous state. Invented by Alan Walsh in 1955, it rapidly became the standard method for trace metal analysis in environmental, clinical, ag

acoustics

Bark and Mel Scales

Bark and Mel scales are perceptual frequency scales that map physical frequency (Hz) to perceived pitch and auditory perception. Formalized by Zwicker (Bark, 1961) and Stevens (Mel, 1937), these non-linear scales reflect how the human ear processes sound. Bark scale divides hearing into 24 critical bands; Mel scale mod

meteorology

Barnes-Cressman Analysis

Barnes-Cressman analysis is an objective interpolation method that creates gridded meteorological fields from irregularly spaced observations (station data, radiosonde profiles, buoys). It is widely used for synoptic analysis, quality control, and initialization of numerical weather models.

astronomy

Baryon Acoustic Oscillations

Baryon Acoustic Oscillations are imprints of sound waves in the early universe that appear as a characteristic scale in the large-scale distribution of galaxies today. First predicted theoretically by Piet Peebles and Joseph Yu in 1970, and detected observationally by the Sloan Digital Sky Survey in 2005, BAO provides

geoscience

Basin Subsidence Analysis

Basin subsidence analysis is the quantitative study of how sedimentary basins deepen over geological time, driven by tectonics, isostasy, and load. Formalized by McKenzie (1978) and Sclater and Christie (1980), this method reveals the mechanical causes of basin development, predicts subsurface temperature and pressure

thermodynamics

Battery Equivalent Circuit Model

The Battery Equivalent Circuit Model (ECM) represents battery electrochemical behavior using an electrical circuit analogy. It includes an ideal voltage source (open-circuit voltage dependent on state of charge), internal resistance(s) for ohmic losses, and capacitive/resistive elements for transient response. ECM enab

particle physics

BDT Particle Identification

Boosted Decision Trees (BDTs) are powerful multivariate classifiers used in particle physics to distinguish between different particle types based on detector signatures. By combining many weak decision trees through adaptive boosting, BDTs achieve superior discrimination power compared to simple cuts, enabling improve

optics

Beam Propagation Method

The Beam Propagation Method is a computational technique for simulating the propagation of optical beams through slowly varying, weakly guiding structures. Developed by Feit and Fleck in 1978, BPM exploits the paraxial approximation to reduce the full vector wave equation to a scalar or vector envelope equation, enabli

acoustics

Beamforming

Beamforming is a spatial signal processing technique that uses microphone arrays to selectively enhance sound from a desired direction while suppressing sounds from other directions. Formalized by Van Veen and Buckley in 1988, beamforming is fundamental to hands-free speech communication, hearing aids, sonar, radar, an

acoustics

BEM Acoustics

The Boundary Element Method (BEM) is a numerical technique for solving acoustic wave equations in complex geometries. Unlike finite element methods (FEM) that mesh entire volumes, BEM discretizes only the acoustic boundaries (surfaces), reducing computational cost and memory. First applied to acoustics by Burton and Mi

oceanography

Benthic Index of Biotic Integrity

The Benthic Index of Biotic Integrity (B-IBI) is an ecological assessment metric that measures the health and integrity of benthic (seafloor) communities based on the composition, abundance, and diversity of benthic fauna. Developed by James Karr in 1981 for freshwater fish assemblages and later adapted for marine bent

thermodynamics

Betz Limit

The Betz Limit states that no wind turbine can extract more than 59.3% of the kinetic energy from flowing wind, regardless of design. This fundamental thermodynamic limit arises because extracting energy slows the wind, which then blocks further energy extraction. Albert Betz derived this limit in 1920 from momentum an

quantum computing

Born-Oppenheimer Approximation

The Born-Oppenheimer (BO) Approximation is a foundational assumption in molecular quantum mechanics that nuclei can be treated as fixed while solving for electrons, and vice versa. Introduced by Born and Oppenheimer in 1927, this separation reduces the complex many-body electronic-nuclear problem to a sequence of simpl

fluid dynamics

Boundary Layer Theory

Boundary Layer Theory is the analytical and approximate framework for understanding viscous flow near solid surfaces, pioneered by Ludwig Prandtl in 1904. The central insight is that at high Reynolds numbers, viscous effects are confined to a thin layer near walls (the boundary layer), while the flow outside remains es

thermodynamics

Boussinesq Approximation

The Boussinesq Approximation simplifies the governing equations for natural convection by treating density as constant except in the buoyancy term. This approximation is valid when temperature variations produce small density changes and allows researchers to solve coupled heat-fluid flow problems without solving the f

thermodynamics

Brayton Cycle

The Brayton Cycle (also called Joule Cycle) describes the thermodynamic process in gas turbines and jet engines. It consists of four processes: isentropic compression in a compressor, isobaric combustion (heat addition), isentropic expansion in a turbine, and isobaric heat rejection. The Brayton Cycle is the foundation

meteorology

Bulk Aerodynamic Flux

The bulk aerodynamic method estimates surface energy and momentum fluxes from standard meteorological observations. Rather than measuring turbulent fluxes directly, it parameterizes them using measurements of wind speed, temperature, and moisture at a reference height (typically 10 m) and surface conditions, multiplied

particle physics

Calorimeter Calibration

Calorimeter calibration establishes the relationship between the measured energy deposited in a detector and the true energy of incident particles. Precise calibration is essential for physics measurements, Higgs boson properties, and new physics searches at colliders, requiring careful control of systematic uncertaint

acoustics

Cepstral Analysis

Cepstral analysis is a spectral analysis technique that decomposes signals into independent components by inverting the log-magnitude spectrum. Pioneered by Bogert, Healy, and Tukey in 1963, cepstral analysis reveals periodic structure in spectra (pitch, echo patterns) and separates source excitation from filter respon

particle physics

Cherenkov Detection

Cherenkov detection exploits the emission of electromagnetic radiation when a charged particle travels through a medium faster than light travels in that same medium. This enables precise particle identification and mass measurement through analysis of Cherenkov light patterns, forming a cornerstone technology in moder

meteorology

Cloud Condensation Nuclei Analysis

Cloud condensation nuclei (CCN) analysis examines the number and properties of aerosol particles capable of nucleating cloud droplets at various supersaturation levels. This field involves measuring CCN concentrations, characterizing their chemical composition and size, and relating aerosol properties to cloud microphy

astronomy

CMB Anisotropy Analysis

The Cosmic Microwave Background is the ancient light from when the universe first became transparent, about 380,000 years after the Big Bang. Its tiny temperature variations (anisotropies) across the sky encode a wealth of information about the universe's composition, geometry, and history. First discovered by Arno Pen

oceanography

CO2SYS

CO2SYS is a widely-used software package for calculating the speciation and equilibrium state of the marine carbonate system from measurements of two carbonate parameters. Developed by Ernie Lewis and Doug Wallace in 1998, CO2SYS enables oceanographers to compute all carbonate species (dissolved CO2, bicarbonate, carbo

chemistry

Column Chromatography

Column chromatography is a liquid separation technique in which a stationary phase (typically silica gel or alumina) is packed into a vertical column, and a mobile phase (solvent) percolates through it to separate mixture components. Pioneered by Mikhail Tsvet in 1903, column chromatography remains the workhorse of org

chemistry

Coordination Compound Synthesis

Coordination compound synthesis is the methodology for preparing metal-ligand complexes, ranging from simple aqueous solutions of metal ions to sophisticated organometallic catalysts and biological metalloproteins. Developed systematically from the 1960s onward by pioneers like Geoffrey Wilkinson and others, coordinati

applied physics

Cosmological Perturbation Theory

Cosmological perturbation theory describes how small density fluctuations in the early universe grow into galaxies, clusters, and large-scale structure under gravity. Originating from James Jeans's 1902 stability analysis and extended by Lifshitz, Bardeen, and others, this theory is the foundation of structure formatio

analytical chemistry

Coulometry

Coulometry is an electrochemical analytical method that determines the concentration of an analyte by measuring the total electric charge (in coulombs) required to oxidize or reduce the analyte completely at an electrode. Developed by James J. Lingane in the 1940s, coulometry is highly accurate because it is based on f

quantum computing

Coupled Cluster CCSD

Coupled Cluster theory, particularly CCSD (Singles and Doubles) and CCSD(T) with perturbative triples, is one of the most accurate methods for molecular electronic structure. Developed by Jiri Cizek in 1966, CC theory treats the ground state wave function as an exponential of excitation operators applied to the Hartree

particle physics

CP Violation Measurement

Charge-Parity (CP) violation measurement is the experimental study of asymmetries between particle and antiparticle processes, a fundamental probe of physics beyond the Standard Model. By comparing decay rates and asymmetries in kaons, B mesons, and neutrinos, physicists constrain new sources of CP violation and addres

chemistry

Crystal Field Theory

Crystal Field Theory (CFT) is a model that explains the electronic structure, color, magnetism, and reactivity of coordination complexes by considering how the electric field created by surrounding ligands perturbs the d-orbitals of a central metal ion. Developed by Hans Bethe in 1929 and refined throughout the 20th ce

applied physics

CSTR Model

The CSTR (Continuous Stirred-Tank Reactor) model describes the behavior of an ideal mixed reactor where fresh feed is continuously added, products are withdrawn, and contents are kept uniform by vigorous stirring. This fundamental model, formalized by Octave Levenspiel in the 1960s, is widely used to design and scale b

oceanography

CTD Profiling

Conductivity-Temperature-Depth (CTD) profiling is the primary method for measuring vertical profiles of seawater properties in oceanography. Developed by Neil Brown in 1977, CTD instruments are equipped with sensors for conductivity, temperature, and pressure (depth), and are typically mounted on water-sampling rosette

oceanography

Degree Heating Weeks

Degree Heating Weeks (DHW) is a thermal stress metric that quantifies accumulated heat exposure above a coral bleaching threshold, computed from satellite sea surface temperature data. Developed by NOAA's Coral Reef Watch program in 2003, DHW provides a standardized index for predicting and monitoring coral bleaching s

quantum computing

Density Functional Theory

Density Functional Theory (DFT) is a computational method for determining the properties of materials and molecules by modeling the ground state electron density. Developed by Walter Kohn and Lu Jeu Sham in the 1960s, DFT reduces the complexity of quantum chemistry from tracking individual electron coordinates to optim

fluid dynamics

Detached Eddy Simulation

Detached Eddy Simulation (DES) is a hybrid turbulence modeling approach introduced by Spalart in 1997 that combines the computational efficiency of RANS in attached boundary layers with the accuracy of LES in separated wake regions. By automatically switching between RANS and LES based on local grid spacing and turbule

fluid dynamics

Direct Numerical Simulation

Direct Numerical Simulation (DNS) is a computational approach that solves the Navier-Stokes equations without turbulence models, resolving all scales of motion from the largest energy-containing eddies down to the smallest dissipative scales (Kolmogorov microscales). Pioneered by Steven Orszag in 1971, DNS provides com

nuclear physics

Dosimetry Measurement

Dosimetry measurement is the experimental quantification of radiation dose and exposure, originating from Röntgen and Becquerel's 1890s discoveries. It employs specialized detectors (ion chambers, TLD, Geiger counters) to measure photon and particle energy deposition in biological tissue or materials, providing direct

oceanography

Drifter Lagrangian Analysis

Drifter Lagrangian analysis tracks the motion of water parcels using surface drifters (buoys with attached drogues) to measure ocean currents directly. Developed by Robert Davis in the 1980s, this method provides direct observation of water parcel trajectories and enables estimation of eddy diffusivity, transport pathw

meteorology

Dual-Polarization Radar

Dual-polarization (dual-pol) radar is a weather radar system that transmits and receives electromagnetic waves in both horizontal and vertical polarizations simultaneously. This technique, operational in weather services since the 2010s, provides detailed information about precipitation particle type, shape, and size d

meteorology

Eddy Covariance

The eddy covariance method is a direct, micrometeorological technique that measures turbulent fluxes of momentum, heat, water vapor, and CO2 by computing the covariance between high-frequency fluctuations of wind velocity and scalar properties (temperature, humidity, concentration). It is the gold standard for measurin

particle physics

Effective Field Theory

Effective Field Theory (EFT) is a general framework for studying physics at low energies in terms of the relevant degrees of freedom, without requiring complete knowledge of high-energy physics. By expanding in powers of energy, EFT provides model-independent parameterizations of new physics effects and systematic meth

thermodynamics

Effectiveness-NTU Method

The Effectiveness-NTU method is an alternative approach to heat exchanger analysis that measures thermal performance relative to the theoretical maximum possible heat transfer. It is particularly powerful for design problems where outlet temperatures are unknown. The method uses effectiveness (ratio of actual to maximu

oceanography

Ekman Transport

Ekman transport is the net volume flux of water driven by wind stress balanced with Coriolis force in the surface boundary layer. Derived by Vagn Walfrid Ekman in 1905 from the principle that wind stress is transmitted through the water column in a spiral pattern, Ekman transport is responsible for coastal upwelling an

geophysics

Electrical Resistivity Tomography

Electrical Resistivity Tomography (ERT) is an active-source geophysical method that maps the spatial distribution of electrical resistivity in the subsurface by injecting current between two electrodes and measuring potential differences across an array of receiver electrodes. Advanced as a practical technique by Loke

applied physics

Electrochemical Impedance Spectroscopy

Electrochemical Impedance Spectroscopy (EIS) is a powerful technique for characterizing electrochemical systems by applying a small AC voltage over a range of frequencies and measuring the resulting current response. Developed in the late 1960s, EIS reveals the frequency-dependent resistance and capacitance of interfac

meteorology

Empirical Orthogonal Teleconnection

Empirical orthogonal function (EOF) analysis is a statistical technique that identifies dominant spatial patterns and temporal variability in atmospheric or oceanic data. When applied to geographically distant locations, EOF analysis reveals teleconnection patterns—coherent patterns of variability that link weather sys