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Density and dense usually refer to a measure of how much of some entity is within a fixed amount of space. Types of density include: In physics, density of mass: * Density, mass per unit volume * * The Planck density, the derived unit of density in the Planck unit system (1 Planck mass divided by 1 Planck volume) * Area density or surface density, mass over a (two-dimensional) area * Linear density, mass over a (one-dimensional) line * Bulk density, mass of many particles of a particulate solid or a powder divided by the total volume they occupy * Particle density or true density, density of the particles that make up a particulate solid or a powder * Relative density or specific gravity, a measure of density in comparison to the density of something else * * Vapour density, a relative density used for gases In physics, densities of entities other than mass: * Number density, number of particles per unit volume, area, or length * Current density, the ratio of electric current to area * Charge density, the electric charge per volume * Energy density, potential energy per unit volume or mass, depending on context * Force density, force per unit volume * ''Optical density'', or ''Neutral density'', the absorbance of an element In mathematics: * Dense set and nowhere dense set in topology * Dense-in-itself, in topology, is a set that contains no isolated points * Schnirelmann density in number theory * Natural density (also called asymptotic density) in number theory * Lebesgue's density theorem in measure theory * Probability density function, a function which maps probabilities across the real line and whose integral is 1 * * Density estimation is the construction of an estimate of a probability density function * * Kernel density estimation, used in statistics to estimate a probability density function of a random variable * Tensor density in differential geometry * Density (graph theory), the fraction of possible edges that exist in a graph * Dense order in order theory * A coinitial subset in the mathematical theory of forcing * Density (polytope) in geometry * Density on a manifold * Dense submodule in abstract algebra In other scientific fields: * Population density, population per unit area * Areal density (computer storage), bits (how computers store information) over an amount of area or volume * Nutrient density, the proportion of any array of a single nutrient or nutritional factor, or of numerous nutrients in foods, often ordered by different scalar indices * Urban density, in urban planning and urban design Density can also refer to: * Spiritual density, levels of spiritual evolution, planes of existence or "dimensions" in ''The Law of One'' * Stupidity, a stupid person is sometimes referred to as being "dense" In Arts: * ''Dense'' (film), a 2004 film * ''Density 21.5'' – a piece of music for solo flute written by Edgard Varèse ==See also== * Concentration * Flux * Intensity (physics) 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Density (disambiguation)」の詳細全文を読む スポンサード リンク
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