text stringlengths 11 320k | source stringlengths 26 161 |
|---|---|
Spatial scale is a specific application of the term scale for describing or categorizing (e.g. into orders of magnitude ) the size of a space (hence spatial ), or the extent of it at which a phenomenon or process occurs. [ 1 ] [ 2 ]
For instance, in physics an object or phenomenon can be called microscopic if too smal... | https://en.wikipedia.org/wiki/Spatial_scale |
Spatial transcriptomics, or spatially resolved transcriptomics , is a method that captures positional context of transcriptional activity within intact tissue. [ 1 ] The historical precursor to spatial transcriptomics is in situ hybridization , [ 2 ] where the modernized omics terminology refers to the measurement of a... | https://en.wikipedia.org/wiki/Spatial_transcriptomics |
Spatial–temporal reasoning is an area of artificial intelligence that draws from the fields of computer science , cognitive science , and cognitive psychology . The theoretic goal—on the cognitive side—involves representing and reasoning spatial-temporal knowledge in mind. The applied goal—on the computing side—involve... | https://en.wikipedia.org/wiki/Spatial–temporal_reasoning |
Spatio-spectral scanning [ 1 ] is one of four techniques for hyperspectral imaging , the other three being spatial scanning, [ 2 ] spectral scanning [ 3 ] and non-scanning, or snapshot hyperspectral imaging .
The technique was designed to put into practice the concept of 'tilted sampling ' of the hyperspectral data cu... | https://en.wikipedia.org/wiki/Spatiospectral_scanning |
Spatiotemporal gene expression is the activation of genes within specific tissues of an organism at specific times during development . Gene activation patterns vary widely in complexity. Some are straightforward and static, such as the pattern of tubulin, which is expressed in all cells at all times in life. Some, on ... | https://en.wikipedia.org/wiki/Spatiotemporal_gene_expression |
Spatiotemporal patterns are patterns that occur in a wide range of natural phenoma and are characterized by a spatial and temporal patterning. The general rules of pattern formation hold. In contrast to "static", pure spatial patterns, the full complexity of spatiotemporal patterns can only be recognized over time. An... | https://en.wikipedia.org/wiki/Spatiotemporal_pattern |
Speakeasy was a numerical computing interactive environment also featuring an interpreted programming language . It was initially developed for internal use at the Physics Division of Argonne National Laboratory by the theoretical physicist Stanley Cohen . [ 4 ] He eventually founded Speakeasy Computing Corporation to ... | https://en.wikipedia.org/wiki/Speakeasy_(computational_environment) |
A special-use permit authorizes land uses that are allowed and encouraged by the ordinance and declared harmonious with the applicable zoning district. [ 1 ]
Land use is governed by a set of regulations generally known as ordinances or municipal codes , which are authorized by the state's zoning enabling law. Within ... | https://en.wikipedia.org/wiki/Special-use_permit |
In logic , especially as applied in mathematics , concept A is a special case or specialization of concept B precisely if every instance of A is also an instance of B but not vice versa, or equivalently, if B is a generalization of A . [ 1 ] A limiting case is a type of special case which is arrived at by taking some a... | https://en.wikipedia.org/wiki/Special_case |
In the petroleum industry , special core analysis , often abbreviated SCAL or SPCAN , is a laboratory procedure [ 1 ] for conducting flow experiments on core plugs taken from a petroleum reservoir . Special core analysis is distinguished from "routine (RCAL) or conventional (CCAL) core analysis" by adding more experime... | https://en.wikipedia.org/wiki/Special_core_analysis |
In mathematics , the special linear group SL ( n , R ) {\displaystyle \operatorname {SL} (n,R)} of degree n {\displaystyle n} over a commutative ring R {\displaystyle R} is the set of n × n {\displaystyle n\times n} matrices with determinant 1 {\displaystyle 1} , with the group operations of ordinary matrix multiplic... | https://en.wikipedia.org/wiki/Special_linear_group |
Specialty chemicals (also called specialties or effect chemicals ) are particular chemical products that provide a wide variety of effects on which many other industry sectors rely. Some of the categories of speciality chemicals are adhesives , agrichemicals , cleaning materials, colors, cosmetic additives , constructi... | https://en.wikipedia.org/wiki/Speciality_chemicals |
In the branch of mathematics known as topology , the specialization (or canonical ) preorder is a natural preorder on the set of the points of a topological space . For most spaces that are considered in practice, namely for all those that satisfy the T 0 separation axiom , this preorder is even a partial order (called... | https://en.wikipedia.org/wiki/Specialization_(pre)order |
Specialized pro-resolving mediators ( SPM , also termed specialized proresolving mediators ) are a large and growing class of cell signaling molecules formed in cells by the metabolism of polyunsaturated fatty acids (PUFA) by one or a combination of lipoxygenase , cyclooxygenase , and cytochrome P450 monooxygenase enzy... | https://en.wikipedia.org/wiki/Specialized_pro-resolving_mediators |
Specialty drugs or specialty pharmaceuticals are a recent designation of pharmaceuticals [ 1 ] [ 2 ] classified as high-cost, [ 3 ] [ 4 ] [ 5 ] high complexity and/or high touch . [ 4 ] Specialty drugs are often biologics [ 3 ] [ 6 ] —"drugs derived from living cells" [ 7 ] that are injectable or infused (although some... | https://en.wikipedia.org/wiki/Specialty_drugs_in_the_United_States |
In the domain of systems engineering , Specialty Engineering is defined as and includes the engineering disciplines that are not typical of the main engineering effort. More common engineering efforts in systems engineering such as hardware , software , and human factors engineering may be used as major elements in a ... | https://en.wikipedia.org/wiki/Specialty_engineering |
Specialty pharmacy refers to distribution channels designed to handle specialty drugs — pharmaceutical therapies that are high cost, [ 1 ] [ 2 ] [ 3 ] high complexity [ 3 ] or high touch . [ 2 ] High touch refers to higher degree of complexity in terms of distribution, administration, or patient management which drives... | https://en.wikipedia.org/wiki/Specialty_pharmacy |
Speciation is the evolutionary process by which populations evolve to become distinct species . The biologist Orator F. Cook coined the term in 1906 for cladogenesis , the splitting of lineages, as opposed to anagenesis , phyletic evolution within lineages. [ 1 ] [ 2 ] [ 3 ] Charles Darwin was the first to describe the... | https://en.wikipedia.org/wiki/Speciation |
The American Species Survival Plan or SSP program was developed in 1981 by the (American) Association of Zoos and Aquariums to help ensure the survival of selected species in zoos and aquariums , [ 1 ] most of which are threatened or endangered in the wild.
SSP programs focus on animals that are near threatened, threa... | https://en.wikipedia.org/wiki/Species_Survival_Plan |
Species affinis (commonly abbreviated to: sp. , aff. , or affin. ) is taxonomic terminology in zoology and botany . In open nomenclature it indicates that available material or evidence suggests that the proposed species is related to, has an affinity to, but is not identical to, the species with the binomial name it c... | https://en.wikipedia.org/wiki/Species_affinis |
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synony... | https://en.wikipedia.org/wiki/Species_complex |
A species description is a formal scientific description of a newly encountered species , typically articulated through a scientific publication . Its purpose is to provide a clear description of a new species of organism and explain how it differs from species that have been previously described or related species. Fo... | https://en.wikipedia.org/wiki/Species_description |
Species distribution , or species dispersion , [ 1 ] is the manner in which a biological taxon is spatially arranged. [ 2 ] The geographic limits of a particular taxon's distribution is its range , often represented as shaded areas on a map. Patterns of distribution change depending on the scale at which they are viewe... | https://en.wikipedia.org/wiki/Species_distribution |
Species distribution modelling (SDM) , also known as environmental (or ecological) niche modelling (ENM) , habitat modelling , predictive habitat distribution modelling , and range mapping [ 1 ] uses ecological models to predict the distribution of a species across geographic space and time using environmental data. Th... | https://en.wikipedia.org/wiki/Species_distribution_modelling |
In biology, a species complex is a group of closely related organisms that are so similar in appearance and other features that the boundaries between them are often unclear. The taxa in the complex may be able to hybridize readily with each other, further blurring any distinctions. Terms that are sometimes used synony... | https://en.wikipedia.org/wiki/Species_flock |
In ecology , species homogeneity is a lack of biodiversity . Species richness is the fundamental unit in which to assess the homogeneity of an environment. Therefore, any reduction in species richness , especially endemic species , could be argued as advocating the production of a homogeneous environment.
Homogeneity ... | https://en.wikipedia.org/wiki/Species_homogeneity |
In biological classification , a species inquirenda is a species of doubtful identity requiring further investigation. [ 2 ] The use of the term in English-language biological literature dates back to at least the early nineteenth century. [ 3 ]
The term taxon inquirendum is broader in meaning and refers to an incompl... | https://en.wikipedia.org/wiki/Species_inquirenda |
The ecological and biogeographical concept of the species pool describes all species available that could potentially colonize and inhabit a focal habitat area. [ 1 ] [ 2 ] The concept lays emphasis on the fact that "local communities aren't closed systems , and that the species occupying any local site typically came ... | https://en.wikipedia.org/wiki/Species_pool |
Species reintroduction is the deliberate release of a species into the wild, from captivity or other areas where the organism is capable of survival. [ 1 ] The goal of species reintroduction is to establish a healthy, genetically diverse , self-sustaining population to an area where it has been extirpated, or to augmen... | https://en.wikipedia.org/wiki/Species_reintroduction |
Species sorting is a mechanism in the metacommunity framework of ecology whereby species distributions and abundances can be related to the environmental or biotic conditions in a particular habitat. The species sorting paradigm [ 1 ] describes a system of habitat patches with different environmental conditions that o... | https://en.wikipedia.org/wiki/Species_sorting |
The species–area relationship or species–area curve describes the relationship between the area of a habitat , or of part of a habitat, and the number of species found within that area. Larger areas tend to contain larger numbers of species, and empirically, the relative numbers seem to follow systematic mathematical r... | https://en.wikipedia.org/wiki/Species–area_relationship |
Specific-pathogen-free (SPF) is a term used for laboratory animals that are guaranteed free of particular pathogens . Use of SPF animals ensures that specified diseases do not interfere with an experiment. For example, absence of respiratory pathogens such as influenza is desirable when investigating a drug's effect on... | https://en.wikipedia.org/wiki/Specific-pathogen-free |
Specific absorption rate ( SAR ) is a measure of the rate at which energy is absorbed per unit mass by a human body when exposed to a radio frequency (RF) electromagnetic field . It is defined as the power absorbed per mass of tissue and has units of watts per kilogram (W/kg). [ 1 ]
SAR is usually averaged either over... | https://en.wikipedia.org/wiki/Specific_absorption_rate |
Specific appetite , also known as specific hunger , is a drive to eat foods with specific flavors or other characteristics. [ 1 ]
Regulation of homeostasis is essential to the survival of animals. Because the nutritional content of a diet will vary with environmental and other conditions, it is useful for animals to h... | https://en.wikipedia.org/wiki/Specific_appetite |
Specific detectivity , or D* , for a photodetector is a figure of merit used to characterize performance, equal to the reciprocal of noise-equivalent power (NEP), normalized per square root of the sensor's area and frequency bandwidth (reciprocal of twice the integration time).
Specific detectivity is given by D ∗ = A... | https://en.wikipedia.org/wiki/Specific_detectivity |
Specific dynamic action ( SDA ), also known as thermic effect of food ( TEF ) or dietary induced thermogenesis ( DIT ), is the amount of energy expenditure above the basal metabolic rate due to the cost of processing food for use and storage. [ 1 ] Heat production by brown adipose tissue which is activated after consum... | https://en.wikipedia.org/wiki/Specific_dynamic_action |
Specific energy or massic energy is energy per unit mass . It is also sometimes called gravimetric energy density , which is not to be confused with energy density , which is defined as energy per unit volume. It is used to quantify, for example, stored heat and other thermodynamic properties of substances such as spec... | https://en.wikipedia.org/wiki/Specific_energy |
Specific Fan Power ( SFP ) is a parameter that quantifies the energy-efficiency of fan air movement systems. It is a measure of the electric power that is needed to drive a fan (or collection of fans), relative to the amount of air that is circulated through the fan(s). It is not constant for a given fan, but changes w... | https://en.wikipedia.org/wiki/Specific_fan_power |
Specific force ( SF ) is a mass-specific quantity defined as the quotient of force per unit mass .
It is a physical quantity of kind acceleration , with dimension of length per time squared and units of metre per second squared (m·s −2 ).
It is normally applied to forces other than gravity , to emulate the relationsh... | https://en.wikipedia.org/wiki/Specific_force |
Specific granules are secretory vesicles found exclusively in cells of the immune system called granulocytes .
It is sometimes described as applying specifically to neutrophils, [ 1 ] and sometimes the term is applied to other types of cells. [ 2 ]
These granules store a mixture of cytotoxic molecules, including many... | https://en.wikipedia.org/wiki/Specific_granule |
In thermodynamics , the specific heat capacity (symbol c ) of a substance is the amount of heat that must be added to one unit of mass of the substance in order to cause an increase of one unit in temperature . It is also referred to as massic heat capacity or as the specific heat. More formally it is the heat capacity... | https://en.wikipedia.org/wiki/Specific_heat_capacity |
Specific impulse (usually abbreviated I sp ) is a measure of how efficiently a reaction mass engine, such as a rocket using propellant or a jet engine using fuel, generates thrust . In general, this is a ratio of the impulse , i.e. change in momentum, per mass of propellant. This is equivalent to "thrust per massflow"... | https://en.wikipedia.org/wiki/Specific_impulse |
In theoretical chemistry , Specific ion Interaction Theory ( SIT theory) is a theory used to estimate single- ion activity coefficients in electrolyte solutions at relatively high concentrations . [ 1 ] [ 2 ] It does so by taking into consideration interaction coefficients between the various ions present in solution. ... | https://en.wikipedia.org/wiki/Specific_ion_interaction_theory |
Specific modulus is a materials property consisting of the elastic modulus per mass density of a material. It is also known as the stiffness to weight ratio or specific stiffness . High specific modulus materials find wide application in aerospace applications where minimum structural weight is required. The dimensiona... | https://en.wikipedia.org/wiki/Specific_modulus |
In the gravitational two-body problem , the specific orbital energy ε {\displaystyle \varepsilon } (or specific vis-viva energy ) of two orbiting bodies is the constant quotient of their mechanical energy (the sum of their mutual potential energy , ε p {\displaystyle \varepsilon _{p}} , and their kinetic energy , ε k {... | https://en.wikipedia.org/wiki/Specific_orbital_energy |
In the natural sciences , including physiology and engineering , a specific quantity generally refers to an intensive quantity obtained by the ratio of an extensive quantity of interest by another extensive quantity (usually mass or volume ). If mass is the divisor quantity, the specific quantity is a massic quantity .... | https://en.wikipedia.org/wiki/Specific_quantity |
In chemistry , specific rotation ( [α] ) is a property of a chiral chemical compound . [ 1 ] : 244 It is defined as the change in orientation of monochromatic plane-polarized light , per unit distance–concentration product, as the light passes through a sample of a compound in solution. [ 2 ] : 2–65 Compounds which rot... | https://en.wikipedia.org/wiki/Specific_rotation |
Specific speed N s , is used to characterize turbomachinery speed. [ 1 ] Common commercial and industrial practices use dimensioned versions which are of equal utility. Specific speed is most commonly used in pump applications to define the suction specific speed [1] —a quasi non-dimensional number that categorizes pum... | https://en.wikipedia.org/wiki/Specific_speed |
In the field of hydrogeology , storage properties are physical properties that characterize the capacity of an aquifer to release groundwater . These properties are storativity (S) , specific storage (S s ) and specific yield (S y ) . According to Groundwater , by Freeze and Cherry (1979), specific storage, S s {\displ... | https://en.wikipedia.org/wiki/Specific_storage |
The specific strength is a material's (or muscle's) strength (force per unit area at failure) divided by its density . It is also known as the strength-to-weight ratio or strength/weight ratio or strength-to-mass ratio . In fiber or textile applications, tenacity is the usual measure of specific strength. The SI unit ... | https://en.wikipedia.org/wiki/Specific_strength |
Specific surface area ( SSA ) is a property of solids defined as the total surface area (SA) of a material per unit mass , [ 1 ] (with units of m 2 /kg or m 2 /g). Alternatively, it may be defined as SA per solid or bulk volume [ 2 ] [ 3 ] (units of m 2 /m 3 or m −1 ).
It is a physical value that can be used to determ... | https://en.wikipedia.org/wiki/Specific_surface_area |
Specific ultraviolet absorbance ( SUVA ) is the absorbance of ultraviolet light in a water sample at a specified wavelength that is normalized for dissolved organic carbon (DOC) concentration. [ 1 ] Specific UV absorbance (SUVA) wavelengths have analytical uses to measure the aromatic character of dissolved organic mat... | https://en.wikipedia.org/wiki/Specific_ultraviolet_absorbance |
In respiratory physiology , specific ventilation is defined as the ratio of the volume of gas entering a region of the lung (ΔV) following an inspiration, divided by the end-expiratory volume (V 0 ) of that same lung region:
SV = ΔV ⁄ V 0
It is a dimensionless quantity. For the whole human lung, given an indicative t... | https://en.wikipedia.org/wiki/Specific_ventilation |
In thermodynamics , the specific volume of a substance (symbol: ν , nu ) is the quotient of the substance's volume ( V ) to its mass ( m ):
It is a mass-specific intrinsic property of the substance. It is the reciprocal of density ρ ( rho ) and it is also related to the molar volume and molar mass :
The standard uni... | https://en.wikipedia.org/wiki/Specific_volume |
The specific weight , also known as the unit weight (symbol γ , the Greek letter gamma ), is a volume-specific quantity defined as the weight W divided by the volume V of a material: γ = W / V {\displaystyle \gamma =W/V} Equivalently, it may also be formulated as the product of density , ρ , and gravity acceleration , ... | https://en.wikipedia.org/wiki/Specific_weight |
This specification is usually called SEMI [ 1 ] E95-0200 standard. It was originally published in February 2000, and the latest technical revision is SEMI E95-1101. [ 2 ]
This standard addresses the area of processing content with the direct intention of developing common software standards, so that problems involving... | https://en.wikipedia.org/wiki/Specification_for_human_interface_for_semiconductor_manufacturing_equipment |
A specification tree shows all specifications of a technical system under development in a hierarchical order.
For a spacecraft system it has the following levels:
This technology-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Specification_tree |
Specificity in symbiosis refers to the taxonomic range with which an organism associates in a symbiosis. [ 1 ] [ 2 ] [ 3 ] [ 4 ] In a symbiosis between a larger organism such as a plant or an animal (called host) and a microorganism (called symbiont ) specificity can be looked at both from the perspective of the host i... | https://en.wikipedia.org/wiki/Specificity_(symbiosis) |
A structural load or structural action is a mechanical load (more generally a force ) applied to structural elements . [ 1 ] [ 2 ] A load causes stress , deformation , displacement or acceleration in a structure . Structural analysis , a discipline in engineering , analyzes the effects of loads on structures and struct... | https://en.wikipedia.org/wiki/Specified_load |
Specim, Spectral Imaging Ltd is a European technology firm headquartered in Oulu , Finland. Specim manufactures and sells imaging spectrographs, hyperspectral cameras and systems. Specim's airborne AISA hyperspectral cameras have been utilized for example in monitoring the environmental effects of major industrial cata... | https://en.wikipedia.org/wiki/Specim |
Specimen provenance complications (SPCs) result from instances of biopsy specimen transposition, extraneous/foreign cell contamination or misidentification of cells used in clinical or anatomical pathology . If left undetected, SPCs can lead to serious diagnostic mistakes and adverse patient outcomes.
According to rec... | https://en.wikipedia.org/wiki/Specimen_provenance_complications |
Specol (trade name Stimune ) is a water in oil adjuvant composed of defined and purified light mineral oil (Stills. 2005). It has been suggested as an alternative to Freund's adjuvant for hyperactivation of the immune response in rabbits (Leenaars et al. 1994). Specol can be used for antigens of low immunogenicity and ... | https://en.wikipedia.org/wiki/Specol |
A spectator ion is an ion that exists both as a reactant and a product in a chemical equation of an aqueous solution . [ 1 ]
For example, in the reaction of aqueous solutions of sodium carbonate and copper(II) sulfate :
The Na + and SO 2− 4 ions are spectator ions since they remain unchanged on both sides of the equa... | https://en.wikipedia.org/wiki/Spectator_ion |
In coordination chemistry , a spectator ligand is a ligand that does not participate in chemical reactions of the complex. Instead, spectator ligands (vs "actor ligands") occupy coordination sites. [ 1 ] Spectator ligands tend to be of polydentate , such that the M-spectator ensemble is inert kinetically. Although they... | https://en.wikipedia.org/wiki/Spectator_ligand |
Mass spectrometry is a scientific technique for measuring the mass-to-charge ratio of ions. It is often coupled to chromatographic techniques such as gas- or liquid chromatography and has found widespread adoption in the fields of analytical chemistry and biochemistry where it can be used to identify and characterize s... | https://en.wikipedia.org/wiki/Spectra_Viewer |
In convex geometry , a spectrahedron is a shape that can be represented as a linear matrix inequality . Alternatively, the set of n × n positive semidefinite matrices forms a convex cone in R n × n , and a spectrahedron is a shape that can be formed by intersecting this cone with an affine subspace .
Spectrahedra are ... | https://en.wikipedia.org/wiki/Spectrahedron |
The Spectral Database for Organic Compounds ( SDBS ) is a free online searchable database hosted by the National Institute of Advanced Industrial Science and Technology (AIST) in Japan, that contains spectral data for ca 34,000 organic molecules. [ 1 ] The database is available in English and in Japanese and it include... | https://en.wikipedia.org/wiki/Spectral_Database_for_Organic_Compounds |
Spectral Genomics, Inc. was a technology spin-off company from Baylor College of Medicine , selling aCGH microarrays and related software.
The company was founded in February 2000 by BCM technologies . Spectral licensed technology invented by its founders Alan Bradley, Ph.D., Wei-wen Cai, Ph.D.. The company raised $3.... | https://en.wikipedia.org/wiki/Spectral_Genomics |
Spectral bands are regions of a given spectrum , having a specific range of wavelengths or frequencies. Most often, it refers to electromagnetic bands , regions of the electromagnetic spectrum . [ 1 ]
More generally, spectral bands may also be means in the spectra of other types of signals, e.g., noise spectrum .
A f... | https://en.wikipedia.org/wiki/Spectral_band |
Bandwidth is the difference between the upper and lower frequencies in a continuous band of frequencies . It is typically measured in unit of hertz (symbol Hz).
It may refer more specifically to two subcategories: Passband bandwidth is the difference between the upper and lower cutoff frequencies of, for example, a b... | https://en.wikipedia.org/wiki/Spectral_bandwidth |
The spectral dimension is a real-valued quantity that characterizes a spacetime geometry and topology . It characterizes a spread into space over time, e.g. an ink drop diffusing in a water glass or the evolution of a pandemic in a population. Its definition is as follow: if a phenomenon spreads as t n {\displaystyle t... | https://en.wikipedia.org/wiki/Spectral_dimension |
A spectral energy distribution ( SED ) is a plot of energy versus frequency or wavelength of light (not to be confused with a 'spectrum' of flux density vs frequency or wavelength). [ 1 ] It is used in many branches of astronomy to characterize astronomical sources. For example, in radio astronomy they are used to sho... | https://en.wikipedia.org/wiki/Spectral_energy_distribution |
Spectral flatness or tonality coefficient , [ 1 ] [ 2 ] also known as Wiener entropy , [ 3 ] [ 4 ] is a measure used in digital signal processing to characterize an audio spectrum . Spectral flatness is typically measured in decibels , and provides a way to quantify how much a sound resembles a pure tone , as opposed t... | https://en.wikipedia.org/wiki/Spectral_flatness |
In spectroscopy , spectral flux density is the quantity that describes the rate at which energy is transferred by electromagnetic radiation through a real or virtual surface, per unit surface area and per unit wavelength (or, equivalently, per unit frequency). It is a radiometric rather than a photometric measure. In S... | https://en.wikipedia.org/wiki/Spectral_flux_density |
In signal processing and related disciplines, aliasing is a phenomenon that a reconstructed signal from samples of the original signal contains low frequency components that are not present in the original one. This is caused when, in the original signal, there are components at frequency exceeding a certain frequency ... | https://en.wikipedia.org/wiki/Spectral_folding |
In quantum mechanics , the spectral gap of a system is the energy difference between its ground state and its first excited state . [ 1 ] [ 2 ] The mass gap is the spectral gap between the vacuum and the lightest particle. A Hamiltonian with a spectral gap is called a gapped Hamiltonian , and those that do not are cal... | https://en.wikipedia.org/wiki/Spectral_gap_(physics) |
Spectral imaging is an umbrella term for energy-resolved X-ray imaging in medicine. [ 1 ] The technique makes use of the energy dependence of X-ray attenuation to either increase the contrast-to-noise ratio , or to provide quantitative image data and reduce image artefacts by so-called material decomposition. Dual-ener... | https://en.wikipedia.org/wiki/Spectral_imaging_(radiography) |
The Fourier transform of a function of time, s(t), is a complex-valued function of frequency, S(f), often referred to as a frequency spectrum . Any linear time-invariant operation on s(t) produces a new spectrum of the form H(f)•S(f), which changes the relative magnitudes and/or angles ( phase ) of the non-zero values... | https://en.wikipedia.org/wiki/Spectral_leakage |
A spectral line is a weaker or stronger region in an otherwise uniform and continuous spectrum . It may result from emission or absorption of light in a narrow frequency range, compared with the nearby frequencies. Spectral lines are often used to identify atoms and molecules . These "fingerprints" can be compared to t... | https://en.wikipedia.org/wiki/Spectral_line |
The analysis of line intensity ratios is an important tool to obtain information about laboratory and space plasmas. In emission spectroscopy , the intensity of spectral lines can provide various information about the plasma (or gas ) condition. It might be used to determine the temperature or density of the plasma. Si... | https://en.wikipedia.org/wiki/Spectral_line_ratios |
Spectral line shape or spectral line profile describes the form of an electromagnetic spectrum in the vicinity of a spectral line – a region of stronger or weaker intensity in the spectrum. Ideal line shapes include Lorentzian , Gaussian and Voigt functions, whose parameters are the line position, maximum height and ha... | https://en.wikipedia.org/wiki/Spectral_line_shape |
In signal processing , the power spectrum S x x ( f ) {\displaystyle S_{xx}(f)} of a continuous time signal x ( t ) {\displaystyle x(t)} describes the distribution of power into frequency components f {\displaystyle f} composing that signal. [ 1 ] According to Fourier analysis , any physical signal can be decomposed in... | https://en.wikipedia.org/wiki/Spectral_phase |
In radiometry , photometry , and color science , a spectral power distribution ( SPD ) measurement describes the power per unit area per unit wavelength of an illumination ( radiant exitance ). More generally, the term spectral power distribution can refer to the concentration, as a function of wavelength, of any radio... | https://en.wikipedia.org/wiki/Spectral_power_distribution |
Spectral purity is a term used in both optics and signal processing . In optics, it refers to the quantification of the monochromaticity of a given light sample. [ 1 ] This is a particularly important parameter in areas like laser operation and time measurement. Spectral purity is easier to achieve in devices that gen... | https://en.wikipedia.org/wiki/Spectral_purity |
Spectral regrowth is the intermodulation products generated in the presence of a digital transmitter added to an analog communication system. [ 1 ]
This electronics-related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Spectral_regrowth |
The spectral resolution of a spectrograph , or, more generally, of a frequency spectrum , is a measure of its ability to resolve features in the electromagnetic spectrum . It is usually denoted by Δ λ {\displaystyle \Delta \lambda } , and is closely related to the resolving power of the spectrograph, defined as R = λ ... | https://en.wikipedia.org/wiki/Spectral_resolution |
Spectral shape analysis relies on the spectrum ( eigenvalues and/or eigenfunctions ) of the Laplace–Beltrami operator to compare and analyze geometric shapes. Since the spectrum of the Laplace–Beltrami operator is invariant under isometries , it is well suited for the analysis or retrieval of non-rigid shapes, i.e. be... | https://en.wikipedia.org/wiki/Spectral_shape_analysis |
In scientific imaging , the two-dimensional spectral signal-to-noise ratio (SSNR) is a signal-to-noise ratio measure which measures the normalised cross-correlation coefficient between several two-dimensional images over corresponding rings in Fourier space as a function of spatial frequency. [ 1 ] It is a multi-partic... | https://en.wikipedia.org/wiki/Spectral_signal-to-noise_ratio |
Spectral signature is the variation of reflectance or emittance of a material with respect to wavelengths (i.e., reflectance/emittance as a function of wavelength). [ 1 ] The spectral signature of stars indicates the composition of the stellar atmosphere . The spectral signature of an object is a function of the incide... | https://en.wikipedia.org/wiki/Spectral_signature |
In radio electronics or acoustics , spectral splatter (also called switch noise ) refers to spurious emissions that result from an abrupt change in the transmitted signal, usually when transmission is started or stopped. [ 1 ]
For example, a device transmitting a sine wave produces a single peak in the frequency spect... | https://en.wikipedia.org/wiki/Spectral_splatter |
In linear algebra and functional analysis , a spectral theorem is a result about when a linear operator or matrix can be diagonalized (that is, represented as a diagonal matrix in some basis). This is extremely useful because computations involving a diagonalizable matrix can often be reduced to much simpler computatio... | https://en.wikipedia.org/wiki/Spectral_theorem |
In mathematics , spectral theory is an inclusive term for theories extending the eigenvector and eigenvalue theory of a single square matrix to a much broader theory of the structure of operators in a variety of mathematical spaces . [ 1 ] It is a result of studies of linear algebra and the solutions of systems of line... | https://en.wikipedia.org/wiki/Spectral_theory |
In telecommunications , spectral width is the width of a spectral band , i.e., the range of wavelengths or frequencies over which the magnitude of all spectral components is significant, i.e., equal to or greater than a specified fraction of the largest magnitude.
In fiber-optic communication applications, the usual m... | https://en.wikipedia.org/wiki/Spectral_width |
A spectrochemical series is a list of ligands ordered by ligand "strength", and a list of metal ions based on oxidation number , group and element. For a metal ion, the ligands modify the difference in energy Δ between the d orbitals , called the ligand-field splitting parameter in ligand field theory , or the crystal-... | https://en.wikipedia.org/wiki/Spectrochemical_series |
Spectrochemistry is the application of spectroscopy in several fields of chemistry. It includes analysis of spectra in chemical terms, and use of spectra to derive the structure of chemical compounds, and also to qualitatively and quantitively analyze their presence in the sample. It is a method of chemical analysis th... | https://en.wikipedia.org/wiki/Spectrochemistry |
Spectroelectrochemistry ( SEC ) is a set of multi-response analytical techniques in which complementary chemical information ( electrochemical and spectroscopic ) is obtained in a single experiment. Spectroelectrochemistry provides a whole vision of the phenomena that take place in the electrode process. [ 1 ] [ 2 ] [ ... | https://en.wikipedia.org/wiki/Spectroelectrochemistry |
The spectroheliograph is an instrument used in astronomy which captures a photographic image of the Sun at a single wavelength of light , a monochromatic image. The wavelength is usually chosen to coincide with a spectral wavelength of one of the chemical elements present in the Sun.
It was developed independently by ... | https://en.wikipedia.org/wiki/Spectroheliograph |
A spectrohelioscope is a type of solar telescope designed by George Ellery Hale in 1924 to allow the Sun to be viewed in a selected wavelength of light. The name comes from Latin- and Greek-based words: "Spectro," referring to the optical spectrum , "helio," referring to the Sun, and "scope," as in telescope.
The basi... | https://en.wikipedia.org/wiki/Spectrohelioscope |
Spectrophotometry is a branch of electromagnetic spectroscopy concerned with the quantitative measurement of the reflection or transmission properties of a material as a function of wavelength. [ 2 ] Spectrophotometry uses photometers , known as spectrophotometers, that can measure the intensity of a light beam at diff... | https://en.wikipedia.org/wiki/Spectrophotometry |
A spectroradiometer is a light measurement tool that is able to measure both the wavelength and amplitude of the light emitted from a light source. Spectrometers discriminate the wavelength based on the position the light hits at the detector array allowing the full spectrum to be obtained with a single acquisition. Mo... | https://en.wikipedia.org/wiki/Spectroradiometer |
Subsets and Splits
No community queries yet
The top public SQL queries from the community will appear here once available.