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Lignin-first biomass fractionation
Lignin-first biomass fractionation is a biorefining method that removes and stabilizes lignin from whole biomass, preventing condensation so both lignin and carbohydrate fractions yield valuable products.
Lignocellulose fractionation
Lignocellulose fractionation is the separation of lignocellulosic biomass, chiefly wood and agricultural residues, into cellulose, hemicellulose, and lignin for independent processing into pulp, sugars, chemicals, or fuels.
Lignoceric acid
Lignoceric acid, also called tetracosanoic acid, is the saturated 24-carbon fatty acid found in brain cerebrosides, plant waxes, and wood tars, and elevated in peroxisomal disorders.
LIGO
LIGO, the Laser Interferometer Gravitational-Wave Observatory, is a pair of 4 km laser interferometers in Washington and Louisiana that made the first direct detection of gravitational waves in 2015.
LIGO–Virgo–KAGRA O4
LIGO–Virgo–KAGRA O4 was the fourth joint observing run of the international gravitational-wave detector network, from May 2023 to November 2025, the longest run yet, raising confident detections to 390.
Lihir Gold Mine
The Lihir Gold Mine is a large open-pit gold mine on Aniolam Island in Papua New Guinea's New Ireland Province, wholly owned by Newmont and producing gold since 1997.
Likelihood function
The likelihood function describes how probable the observed data are under each candidate parameter value of a statistical model, and is central to maximum likelihood estimation and Bayesian inference.
Likelihood principle
The likelihood principle is a principle of statistical inference stating that the likelihood function fully captures the evidence in experimental data, independent of the experimental design.
Likelihood ratios in diagnostic testing
Likelihood ratios in diagnostic testing: LR+ = sensitivity/(1−specificity), LR− = (1−sensitivity)/specificity; they convert pretest odds to posttest odds via Bayes' theorem, are prevalence-independent, and guide rule-in and rule-out decisions.
Likelihood-free inference (statistics)
Likelihood-free inference is a family of simulation-based statistical methods, including approximate Bayesian computation (ABC), that estimate posterior distributions for models whose likelihood is intractable but whose data can be simulated.
Likelihood-ratio test
The likelihood-ratio test, also known as the LR test, is a statistical test comparing two nested models fitted by maximum likelihood, introduced by Neyman and Pearson in 1928.
Likert scale
A Likert scale is a psychometric instrument measuring attitudes, introduced by Rensis Likert in 1932, with respondents rating statements from strong disagreement to strong agreement.
LIL (CERN)
LIL (LEP Injector Linac) was a pair of linear accelerators at CERN, built with LAL Orsay, that produced the electrons and positrons feeding LEP from 1989 until 2000.
Limaçon
The limaçon, also called Pascal's snail, is a plane algebraic curve of order 4, the conchoid of a circle taken with respect to a point on its circumference.
Limb darkening
Limb darkening, also called stellar limb darkening, is the decrease in a star's observed brightness from disk center toward its edge, seen visibly on the Sun.
Lime (material)
Lime is a family of calcium chemicals, chiefly quicklime and hydrated lime, produced by heating limestone in kilns and used above all in steelmaking and construction.
Limestone
Limestone is a sedimentary rock consisting chiefly of calcium carbonate, formed from shells and mud on ocean and lake bottoms, and widely used to make Portland cement and lime.
Liming Dai
Liming Dai is a materials scientist and Scientia Professor at UNSW Sydney known for carbon-based metal-free electrocatalysts, opened by his 2009 Science paper on nitrogen-doped carbon nanotubes beating platinum.
Liming Zhang
Liming Zhang (张立明) is an organic chemist known for his work in homogeneous gold catalysis, including Au(I)/Au(III) redox catalysis, and a professor at UC Santa Barbara.
Limit (category theory)
In category theory, a limit of a diagram is a universal cone that every other cone factors through uniquely, generalizing products, equalizers, pullbacks, and terminal objects; it was named by Daniel Kan in 1958.
Limit (mathematics)
In mathematics, a limit is the value a function or sequence approaches as its input approaches some value, the foundational concept underlying continuity, derivatives, integrals, and convergence.
Limit cycle
A limit cycle is an isolated closed trajectory in the phase space of a differential equation, a periodic solution that nearby trajectories spiral toward or away from.
Limit of a function
The limit of a function is the value its output approaches as its input approaches a given point, and it underlies continuity, derivatives, and integrals in calculus.
Limit of a sequence
The limit of a sequence is the number its terms approach and stay near; a sequence with such a number is called convergent, one without, divergent.
Limit ordinal
A limit ordinal is a nonzero ordinal number that has no immediate predecessor, so it is not the successor of any ordinal; the first example is ω, the smallest infinite ordinal.
Limit point
A limit point, also called an accumulation point or cluster point, of a set is a point every neighborhood of which contains a point of the set other than itself.
Limit superior and limit inferior
The limit superior (limsup) and limit inferior (liminf) of a real sequence are its eventual upper and lower bounds, obtained from the suprema and infima of its tails.
Limited information maximum likelihood
Limited information maximum likelihood (LIML) is a single-equation instrumental-variable estimator for a structural equation in a simultaneous-equations system, introduced by Anderson and Rubin in 1949.
Limiter (plasma physics)
In magnetic-confinement fusion, a limiter is a material surface inside a tokamak or stellarator that defines the plasma edge and protects the wall, largely replaced by divertors.
Limiting reagent
The limiting reagent, also called the limiting reactant, is the reactant in a chemical reaction that is completely consumed first and therefore determines how much product can form.