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The Penrose–Lucas argument is a logical argument partially based on a theory developed by mathematician and logician Kurt Gödel . In 1931, he proved that every effectively generated theory capable of proving basic arithmetic either fails to be consistent or fails to be complete . Due to human ability to see the truth o... | https://en.wikipedia.org/wiki/Penrose–Lucas_argument |
The Pensky–Martens closed-cup flash-point test is a test for the determination of the flash point of flammable liquids. It is standardized as ASTM D93, EN ISO 2719 and IP 34 [ 1 ] The United States Environmental Protection Agency (EPA) has also published Method 1010A: Test Methods for Flash Point by Pensky-Martens Clos... | https://en.wikipedia.org/wiki/Pensky–Martens_closed-cup_test |
Penta-graphene is a hypothetical carbon allotrope composed entirely of carbon pentagons and resembling the Cairo pentagonal tiling . [ 2 ] Penta-graphene was proposed in 2014 on the basis of analyses and simulations. [ 2 ] Further calculations predicted that it is unstable in its pure form, [ 3 ] but can be stabilized ... | https://en.wikipedia.org/wiki/Penta-graphene |
Pentabromodiphenyl ether (also known as pentabromodiphenyl oxide ) is a brominated flame retardant which belongs to the group of polybrominated diphenyl ethers (PBDEs). Because of their toxicity and persistence, their industrial production is to be eliminated under the Stockholm Convention , a treaty to control and pha... | https://en.wikipedia.org/wiki/Pentabromodiphenyl_ether |
Pentachlorobenzene (PeCB) is an aryl chloride and a five-substituted chlorobenzene with the molecular formula C 6 HCl 5 which is a chlorinated aromatic hydrocarbon . It consists of a benzene ring substituted with five chlorine atoms. PeCB was once used industrially for a variety of uses, but because of environmental ... | https://en.wikipedia.org/wiki/Pentachlorobenzene |
Pentachloronitrobenzene , typically abbreviated PCNB , is a registered fungicide formally derived from nitrobenzene . It is a off-white to yellow crystalline solid with a musty odor.
PCNB was originally synthesized in the laboratory in 1868. It was introduced to the agricultural world in the 1930s in Germany by Bayer ... | https://en.wikipedia.org/wiki/Pentachloronitrobenzene |
Pentachlorophenol ( PCP ) is an organochlorine compound used as a pesticide and a disinfectant . First produced in the 1930s, it is marketed under many trade names. [ 5 ] It can be found as pure PCP, or as the sodium salt of PCP, the latter of which dissolves easily in water. It can be biodegraded by some bacteria, in... | https://en.wikipedia.org/wiki/Pentachlorophenol |
In organic chemistry , pentadiene is any hydrocarbon with an open chain of five carbons , connected by two single bonds and two double bonds . All those compounds have the same molecular formula C 5 H 8 . The inventory of pentadienes include:
Well known derivatives containing pentadiene groups include hexadienes , cyc... | https://en.wikipedia.org/wiki/Pentadiene |
Pentaerythritol tetranitrate ( PETN ), also known as PENT , pentyl , PENTA ( ПЕНТА , primarily in Russian), TEN (tetraeritrit nitrate), corpent , or penthrite (or, rarely and primarily in German, as nitropenta ), is an explosive material. It is the nitrate ester of pentaerythritol , and is structurally very similar to ... | https://en.wikipedia.org/wiki/Pentaerythritol_tetranitrate |
Pentafluorophenyl ( PFP ) esters are chemical compounds with the generic formula RC(O)OC 6 F 5 . They are active esters derived from pentafluorophenol (HOC 6 F 5 ).
PFP esters are useful for attaching fluorophores such as fluorescein [ 1 ] or haptens [ 2 ] to primary amines in biomolecules. They also are valuable in l... | https://en.wikipedia.org/wiki/Pentafluorophenyl_esters |
Pentagastrin (trade name Peptavlon ) is a synthetic polypeptide that has effects like gastrin when given parenterally . [ 2 ] It stimulates the secretion of gastric acid , pepsin , and intrinsic factor , and has been used as a diagnostic aid as the pentagastrin-stimulated calcitonin test .
Pentagastrin binds to the ch... | https://en.wikipedia.org/wiki/Pentagastrin-stimulated_calcitonin_test |
In chemistry , a pentagonal bipyramid is a molecular geometry with one atom at the centre with seven ligands at the corners of a pentagonal bipyramid . A perfect pentagonal bipyramid belongs to the molecular point group D 5h .
The pentagonal bipyramid is a case where bond angles surrounding an atom are not identical (... | https://en.wikipedia.org/wiki/Pentagonal_bipyramidal_molecular_geometry |
In chemistry , the pentagonal planar molecular geometry describes the shape of compounds where five atoms , groups of atoms, or ligands are arranged around a central atom, defining the vertices of a pentagon .
The only two pentagonal planar species known are the isoelectronic (nine valence electrons ) ions [XeF 5 ] − ... | https://en.wikipedia.org/wiki/Pentagonal_planar_molecular_geometry |
In chemistry , pentagonal pyramidal molecular geometry describes the shape of compounds where in six atoms or groups of atoms or ligands are arranged around a central atom, at the vertices of a pentagonal pyramid . It is one of the few molecular geometries with uneven bond angles . [ 1 ]
Pentagonal pyramid , Wolfram ... | https://en.wikipedia.org/wiki/Pentagonal_pyramidal_molecular_geometry |
A pentagram (sometimes known as a pentalpha, pentangle, or star pentagon) is a regular five-pointed star polygon , formed from the diagonal line segments of a convex (or simple, or non-self-intersecting) regular pentagon . Drawing a circle around the five points creates a similar symbol referred to as the pentacle , [ ... | https://en.wikipedia.org/wiki/Pentagram |
In mathematics , the pentagram map is a discrete dynamical system on the moduli space of polygons in the projective plane . The pentagram map takes a given polygon, finds the intersections of the shortest diagonals of the polygon, and constructs a new polygon from these intersections. Richard Schwartz introduced the pe... | https://en.wikipedia.org/wiki/Pentagram_map |
In the geometry of hyperbolic 4-space , the pentagrammic-order 600-cell honeycomb is one of four regular star- honeycombs . With Schläfli symbol {3,3,5,5/2}, it has five 600-cells around each face in a pentagrammic arrangement. It is dual to the small stellated 120-cell honeycomb . It can be considered the higher-dimen... | https://en.wikipedia.org/wiki/Pentagrammic-order_600-cell_honeycomb |
Pentamethylantimony or pentamethylstiborane is an organometalllic compound containing five methyl groups bound to an antimony atom with formula Sb(CH 3 ) 5 . It is an example of a hypervalent compound. The molecular shape is trigonal bipyramid . [ 1 ] Some other antimony(V) organometallic compounds include pentapropyn... | https://en.wikipedia.org/wiki/Pentamethylantimony |
Pentamethylarsenic (or pentamethylarsorane [ 1 ] ) is an organometalllic compound containing five methyl groups bound to an arsenic atom with formula As(CH 3 ) 5 . It is an example of a hypervalent compound. The molecular shape is trigonal bipyramid . [ 2 ]
The first claim to make pentamethylarsenic was in 1862 in a ... | https://en.wikipedia.org/wiki/Pentamethylarsenic |
Pentamethylbismuth (or pentamethylbismuthorane [ 2 ] ) is an organometalllic compound containing five methyl groups bound to a bismuth atom with formula Bi(CH 3 ) 5 . It is an example of a hypervalent compound. The molecular shape is trigonal bipyramid . [ 3 ]
Pentamethylbismuth is produced in a two step process. Fi... | https://en.wikipedia.org/wiki/Pentamethylbismuth |
Pentamethyltantalum is a homoleptic organotantalum compound.
It has a propensity to explode when it is melted. [ 4 ] Its discovery was part of a sequence that led to Richard R. Schrock 's Nobel Prize winning discovery in olefin metathesis . [ 5 ]
Pentamethyltantalum can be made from the reaction of methyllithium with ... | https://en.wikipedia.org/wiki/Pentamethyltantalum |
This page provides supplementary chemical data on n -pentane .
The handling of this chemical may incur notable safety precautions. It is highly recommend that you seek the Material Safety Datasheet ( MSDS ) for this chemical from a reliable source such as eChemPortal , and follow its directions.
Table data obtained f... | https://en.wikipedia.org/wiki/Pentane_(data_page) |
Pentane interference or syn -pentane interaction is the steric hindrance that the two terminal methyl groups experience in one of the chemical conformations of n-pentane . The possible conformations are combinations of anti conformations and gauche conformations and are anti-anti, anti-gauche + , gauche + - gauche + an... | https://en.wikipedia.org/wiki/Pentane_interference |
In organic chemistry , pentanonide is a functional group which is composed of a cyclic ketal of a diol with 3-pentanone . [ 1 ] It is seen in amcinafal (triamcinolone pentanonide). [ 1 ]
This organic chemistry article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Pentanonide |
Pentanoyl chloride is an acyl chloride derived from pentanoic acid . It is a colorless liquid that is used to attach the valeroyl group. It is usually produced by chlorination of valeric acid . [ 1 ]
Like related acyl chlorides , valeryl chloride hydrolyzes readily:
Alcohols react to give esters:
Amines react to gi... | https://en.wikipedia.org/wiki/Pentanoyl_chloride |
Pentaoxidane is an inorganic compound of hydrogen and oxygen with the chemical formula H 2 O 5 . [ 1 ] This is one of the most unstable hydrogen polyoxides . [ 2 ] [ 3 ] [ 4 ] | https://en.wikipedia.org/wiki/Pentaoxidane |
Pentaoxygen difluoride is a binary inorganic compound of fluorine and oxygen with the chemical formula O 5 F 2 . [ 1 ] [ 2 ] The compound is one of many known oxygen fluorides .
The compound can be prepared by electric discharges through the F 2 — O 2 mixture of the certain molar ratio at 60 to 77 K. The ratio is pred... | https://en.wikipedia.org/wiki/Pentaoxygen_difluoride |
Pentaphenylantimony is an organoantimony compound containing five phenyl groups attached to one antimony atom. It has formula Sb(C 6 H 5 ) 5 (or SbPh 5 ).
The structure of pentaphenylantimony has been the subject of several studies, and a definite ground state remains uncertain. The molecule adopts a roughly square ... | https://en.wikipedia.org/wiki/Pentaphenylantimony |
In mathematics , pentation (or hyper-5 ) is the fifth hyperoperation . Pentation is defined to be repeated tetration , similarly to how tetration is repeated exponentiation , exponentiation is repeated multiplication , and multiplication is repeated addition . The concept of "pentation" was named by English mathematici... | https://en.wikipedia.org/wiki/Pentation |
In chemistry , the pentazenium cation (also known as pentanitrogen ) is a positively-charged polyatomic ion with the chemical formula N + 5 and structure N−N−N−N−N . Together with solid nitrogen polymers and the azide anion, it is one of only three poly- nitrogen species obtained in bulk quantities.
Within the High En... | https://en.wikipedia.org/wiki/Pentazenium |
Pentazine is a hypothetical chemical compound that consists of a six-membered aromatic ring containing five nitrogen atoms with the molecular formula C H N 5 . The name pentazine is used in the nomenclature of derivatives of this compound.
Pentazine is predicted to be unstable and to decompose into hydrogen cyanide (... | https://en.wikipedia.org/wiki/Pentazine |
Pentazole is an aromatic molecule consisting of a five-membered ring with all nitrogen atoms, one of which is bonded to a hydrogen atom. It has the molecular formula HN 5 . Although strictly speaking a homocyclic , inorganic compound , pentazole has historically been classed as the last in a series of heterocyclic azol... | https://en.wikipedia.org/wiki/Pentazole |
Pentosans are polymers composed of pentoses . In contrast to cellulose , which is composed of hexose ( glucose ) monomers , pentosans are derived from five-carbon sugars such as xylose . Pentosan-rich biomass is the precursor to furfural . [ 1 ]
The pentosan content has been determined for many natural materials: [ 1 ... | https://en.wikipedia.org/wiki/Pentosan |
Pentosidine is a biomarker for advanced glycation endproducts , or AGEs. It is a well characterized and easily detected member of this large class of compounds.
AGEs are biochemicals formed continuously under normal circumstances, but more rapidly under a variety of stresses, especially oxidative stress and hyperglyc... | https://en.wikipedia.org/wiki/Pentosidine |
A pepper-spray projectile , also called a pepper-spray ball , pepper-ball , pepper bomb , or pepper-spray pellet , is a frangible projectile containing a powdered chemical that irritates the eyes and nose in a manner similar to pepper spray . These projectiles are fired from specially designed forced compliance weapons... | https://en.wikipedia.org/wiki/Pepper-spray_projectile |
Pepper spray , oleoresin capsicum spray , OC spray , capsaicin spray , mace , or capsicum spray is a lachrymator (tear gas) product containing as its active ingredient the chemical compound capsaicin , which irritates the eyes with burning and pain sensations and so causes them to close, bringing temporary blindness. T... | https://en.wikipedia.org/wiki/Pepper_spray |
Pepperl+Fuchs SE (sometimes referenced by the initialism P+F ) is a German multinational company headquartered in Mannheim , Germany . The company manufactures electronic products for fabrication and process automation. It specializes in sensor manufacturing, such as sensors used in automatic doors in elevators, encode... | https://en.wikipedia.org/wiki/Pepperl+Fuchs |
Pepscan is a procedure for mapping and characterizing epitopes involving the synthesis of overlapping peptides and analysis of the peptides in enzyme-linked immunosorbent assays (ELISAs). The method is based on combinatorial chemistry and was pioneered by Mario Geysen and coworkers. [ 1 ]
Rob Meloen was one of Geysen'... | https://en.wikipedia.org/wiki/Pepscan |
In bio-informatics , a peptide-mass fingerprint or peptide-mass map is a mass spectrum of a mixture of peptides that comes from a digested protein being analyzed. The mass spectrum serves as a fingerprint in the sense that it is a pattern that can serve to identify the protein. [ 1 ] The method for forming a peptide-m... | https://en.wikipedia.org/wiki/Peptide-mass_fingerprint |
Peptide PHI, also known as peptide histidine isoleucine , is a peptide which functions as a hormone . This peptide contains a composition of 27 amino acids with histidine on the N-terminus and isoleucine on the C-terminus . It was originally isolated from the mammalian small intestine amongst mammalian neurons called i... | https://en.wikipedia.org/wiki/Peptide_PHI |
In organic chemistry , a peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 ( carbon number one) of one alpha-amino acid and N2 ( nitrogen number two) of another, along a peptide or protein chain. [ 1 ]
It can also be called a eupeptide bond [ 1 ] to distinguish i... | https://en.wikipedia.org/wiki/Peptide_bond |
Peptide computing is a form of computing which uses peptides , instead of traditional electronic components . The basis of this computational model is the affinity of antibodies towards peptide sequences. Similar to DNA computing , the parallel interactions of peptide sequences and antibodies have been used by this mod... | https://en.wikipedia.org/wiki/Peptide_computing |
A peptide library is a tool for studying proteins . Peptide libraries typically contain a large number of peptides that have a systematic combination of amino acids . Usually, solid phase synthesis, e.g. resin as a flat surface or beads, is used for peptide library generation. Peptide libraries are a popular tool for e... | https://en.wikipedia.org/wiki/Peptide_library |
Peptide mass fingerprinting ( PMF ), also known as protein fingerprinting , is an analytical technique for protein identification in which the unknown protein of interest is first cleaved into smaller peptides , whose absolute masses can be accurately measured with a mass spectrometer such as MALDI-TOF or ESI-TOF . [ 1... | https://en.wikipedia.org/wiki/Peptide_mass_fingerprinting |
A peptide microarray (also commonly known as peptide chip or peptide epitope microarray) is a collection of peptides displayed on a solid surface, usually a glass or plastic chip. Peptide chips are used by scientists in biology, medicine and pharmacology to study binding properties and functionality and kinetics of pro... | https://en.wikipedia.org/wiki/Peptide_microarray |
Peptide plane flipping is a type of conformational change that can occur in proteins by which the dihedral angles of adjacent amino acids undergo large-scale rotations with little displacement of the side chains . The plane flip is defined as a rotation of the dihedral angles φ,ψ at amino acids i and i+1 such that the ... | https://en.wikipedia.org/wiki/Peptide_plane_flipping |
Protein primary structure is the linear sequence of amino acids in a peptide or protein . [ 1 ] By convention, the primary structure of a protein is reported starting from the amino -terminal (N) end to the carboxyl -terminal (C) end. Protein biosynthesis is most commonly performed by ribosomes in cells. Peptides can a... | https://en.wikipedia.org/wiki/Peptide_sequence |
A peptide spectral library is a curated, annotated and non-redundant collection/database of LC-MS /MS peptide spectra. One essential utility of a peptide spectral library is to serve as consensus templates supporting the identification of peptides and proteins based on the correlation between the templates with experim... | https://en.wikipedia.org/wiki/Peptide_spectral_library |
In organic chemistry , peptide synthesis is the production of peptides , compounds where multiple amino acids are linked via amide bonds, also known as peptide bonds . Peptides are chemically synthesized by the condensation reaction of the carboxyl group of one amino acid to the amino group of another. Protecting group... | https://en.wikipedia.org/wiki/Peptide_synthesis |
Peptidoglycan or murein is a unique large macromolecule, a polysaccharide , consisting of sugars and amino acids that forms a mesh-like layer (sacculus) that surrounds the bacterial cytoplasmic membrane. [ 1 ] The sugar component consists of alternating residues of β-(1,4) linked N -acetylglucosamine (NAG) and N -acety... | https://en.wikipedia.org/wiki/Peptidoglycan |
A peptidomimetic is a small protein-like chain designed to mimic a peptide . [ 1 ] [ 2 ] They typically arise either from modification of an existing peptide, or by designing similar systems that mimic peptides, such as peptoids and β-peptides . Irrespective of the approach, the altered chemical structure is designed ... | https://en.wikipedia.org/wiki/Peptidomimetic |
The peptization of a liquid mixture is the process of converting the mixture into a colloid by shaking it with a suitable electrolyte called a peptizing agent . [ 1 ] That is, the insoluble solid particles which have settled out of the mixture (i.e. the precipitate ) are reformed into microscopic particles suspended in... | https://en.wikipedia.org/wiki/Peptization |
In nanobiotechnology , a peptoid nanosheet is a synthetic protein structure made from peptoids . Peptoid nanosheets have a thickness of about three nanometers and a length of up to 100 micrometers, meaning that they have a two-dimensional, flat shape that resembles paper on the nanoscale. [ 1 ] [ 2 ]
For assembly, a p... | https://en.wikipedia.org/wiki/Peptoid_nanosheet |
Per-Olov Löwdin (October 28, 1916 – October 6, 2000) was a Swedish physicist , professor at the University of Uppsala from 1960 to 1983, and in parallel at the University of Florida until 1993.
A former graduate student under Ivar Waller , Löwdin formulated in 1950 the symmetric orthogonalization scheme for atomic and... | https://en.wikipedia.org/wiki/Per-Olov_Löwdin |
Per- and polyfluoroalkyl substances (also PFAS , [ 1 ] PFASs , [ 2 ] and sometimes referred to as " forever chemicals " [ 3 ] [ 4 ] ) are a group of synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain; there are 7 million such chemicals according to PubChem . [ 5 ] P... | https://en.wikipedia.org/wiki/Per-_and_polyfluoroalkyl_substances |
In the power systems analysis field of electrical engineering , a per-unit system is the expression of system quantities as fractions of a defined base unit quantity. Calculations are simplified because quantities expressed as per-unit do not change when they are referred from one side of a transformer to the other. Th... | https://en.wikipedia.org/wiki/Per-unit_system |
Per-user unitary rate control ( PU 2 RC ) is a multi-user MIMO (multiple-input and multiple-output) scheme. PU 2 RC uses both transmission pre-coding and multi-user scheduling. By doing that, the network capacity is further enhanced than the capacity of the single-user MIMO scheme.
Recently, PU 2 RC has been adopted i... | https://en.wikipedia.org/wiki/Per-user_unitary_rate_control |
The phrase per meg indicates a fraction equal to 0.001 permil , or 0.0001 percent , or 1 part per million ( ppm ). It is typically used as a unit in isotope analysis , where multiplying an isotope ratio in delta annotation, for example δ 18 O , by 1000000 yields a value in per meg. [ 1 ] [ 2 ] This notation is most fre... | https://en.wikipedia.org/wiki/Per_meg |
Perceived performance , in computer engineering , refers to how quickly a software feature appears to perform its task. The concept applies mainly to user acceptance aspects.
The amount of time an application takes to start up, or a file to download, is not made faster by showing a startup screen (see Splash screen ) ... | https://en.wikipedia.org/wiki/Perceived_performance |
In human visual perception , the visual angle , denoted θ , subtended by a viewed object sometimes looks larger or smaller than its actual value. One approach to this phenomenon posits a subjective correlate to the visual angle: the perceived visual angle or perceived angular size . An optical illusion where the physic... | https://en.wikipedia.org/wiki/Perceived_visual_angle |
The percent sign % (sometimes per cent sign in British English ) is the symbol used to indicate a percentage , a number or ratio as a fraction of 100. Related signs include the permille (per thousand) sign ‰ and the permyriad (per ten thousand) sign ‱ (also known as a basis point ), which indicate that a number is divi... | https://en.wikipedia.org/wiki/Percent_sign |
A percentage point or percent point is the unit for the arithmetic difference between two percentages . For example, moving up from 40 percent to 44 percent is an increase of 4 percentage points (although it is a 10-percent increase in the quantity being measured, if the total amount remains the same). [ 1 ] In written... | https://en.wikipedia.org/wiki/Percentage_point |
Perceptual Audio Coder ( PAC ) is a lossy audio compression algorithm. It is used by Sirius Satellite Radio for their digital audio radio service .
The original version of PAC developed by James Johnston and Anibal Ferreira at AT&T's Bell Labs has a flexible format and bitrate . It provides efficient compression of hi... | https://en.wikipedia.org/wiki/Perceptual_Audio_Coder |
A perceptual trap is an ecological scenario in which environmental change , typically anthropogenic , leads an organism to avoid an otherwise high-quality habitat . The concept is related to that of an ecological trap , in which environmental change causes preference towards a low-quality habitat.
In a 2004 article di... | https://en.wikipedia.org/wiki/Perceptual_trap |
A perchlorate is a chemical compound containing the perchlorate ion , ClO − 4 , the conjugate base of perchloric acid ( ionic perchlorate ). As counterions, there can be metal cations , quaternary ammonium cations or other ions, for example, nitronium cation ( NO + 2 ).
The term perchlorate can also describe perchlora... | https://en.wikipedia.org/wiki/Perchlorate |
Percobaltates are chemical compounds where the oxidation state of cobalt is +5. This is the highest established oxidation state of cobalt. [ 1 ] The simplest of these are bi-metallic Group 1 oxides such as sodium percobaltate (Na 3 CoO 4 ); which may be produced by the reaction of cobalt(II,III) oxide and sodium oxide ... | https://en.wikipedia.org/wiki/Percobaltate |
A percolation trench , also called an infiltration trench , is a type of best management practice (BMP) that is used to manage stormwater runoff , prevent flooding and downstream erosion , and improve water quality in an adjacent river , stream , lake or bay . It is a shallow excavated trench filled with gravel or crus... | https://en.wikipedia.org/wiki/Percolation_trench |
Percoll is a reagent consisting of colloidal silica particles used in cell biology and other laboratory settings. It was first formulated by Pertoft and colleagues, [ 2 ] and commercialized by Pharmacia Fine Chemicals . [ 3 ] Percoll is used for the isolation of cells , organelles , or viruses by density centrifugation... | https://en.wikipedia.org/wiki/Percoll |
In statistical mechanics the Percus–Yevick approximation [ 1 ] is a closure relation to solve the Ornstein–Zernike equation . It is also referred to as the Percus–Yevick equation . It is commonly used in fluid theory to obtain e.g. expressions for the radial distribution function . The approximation is named after Jero... | https://en.wikipedia.org/wiki/Percus–Yevick_approximation |
The Percy L. Julian Award was first given in 1975 by the National Organization for the Professional Advancement of Black Chemists and Chemical Engineers (NOBCChE). The award is given every one to two years. It honors black scientists who have made significant contributions to the areas of pure or applied research in sc... | https://en.wikipedia.org/wiki/Percy_L._Julian_Award |
The Peregrine soliton (or Peregrine breather ) is an analytic solution of the nonlinear Schrödinger equation . [ 1 ] This soliton or breather solution was proposed in 1983 by Howell Peregrine , researcher at the mathematics department of the University of Bristol .
Contrary to the usual fundamental soliton that can ma... | https://en.wikipedia.org/wiki/Peregrine_soliton |
In botany , perennation is the ability of organisms , particularly plants , to survive from one germinating season to another, especially under unfavourable conditions such as drought or winter cold. It typically involves development of a perennating organ , which stores enough nutrients to sustain the organism during ... | https://en.wikipedia.org/wiki/Perennation |
In mathematical physics , the Peres metric is defined by the proper time
for any arbitrary function f . If f is a harmonic function with respect to x and y , then the corresponding Peres metric satisfies the Einstein field equations in vacuum . Such a metric is often studied in the context of gravitational waves . ... | https://en.wikipedia.org/wiki/Peres_metric |
The Peres–Horodecki criterion is a necessary condition, for the joint density matrix ρ {\displaystyle \rho } of two quantum mechanical systems A {\displaystyle A} and B {\displaystyle B} , to be separable . It is also called the PPT criterion, for positive partial transpose . In the 2×2 and 2×3 dimensional cases the co... | https://en.wikipedia.org/wiki/Peres–Horodecki_criterion |
Perfect Timing Holding (PTH) is a multinational group of companies headquartered in Turkey . It operates in Europe , Asia , America , and Africa . [ 1 ] [ 2 ]
PTH was established in 2000, through the merger of two family businesses: the Huseby company, founded in 1880 in America, and Yavuz, founded in 1925 in Turkey. ... | https://en.wikipedia.org/wiki/Perfect_Timing_Holding |
In algebra, a perfect complex of modules over a commutative ring A is an object in the derived category of A -modules that is quasi-isomorphic to a bounded complex of finite projective A -modules. A perfect module is a module that is perfect when it is viewed as a complex concentrated at degree zero. For example, if A ... | https://en.wikipedia.org/wiki/Perfect_complex |
In electrostatics , a perfect conductor is an idealized model for real conducting materials. The defining property of a perfect conductor is that static electric field and the charge density both vanish in its interior. If the conductor has excess charge, it accumulates as an infinitesimally thin layer of surface charg... | https://en.wikipedia.org/wiki/Perfect_conductor |
In number theory , a perfect digital invariant (PDI) is a number in a given number base ( b {\displaystyle b} ) that is the sum of its own digits each raised to a given power ( p {\displaystyle p} ). [ 1 ] [ 2 ]
Let n {\displaystyle n} be a natural number . The perfect digital invariant function (also known as a happy... | https://en.wikipedia.org/wiki/Perfect_digital_invariant |
In graph theory , the perfect graph theorem of László Lovász ( 1972a , 1972b ) states that an undirected graph is perfect if and only if its complement graph is also perfect. This result had been conjectured by Berge ( 1961 , 1963 ), and it is sometimes called the weak perfect graph theorem to distinguish it from the s... | https://en.wikipedia.org/wiki/Perfect_graph_theorem |
In mathematics , more specifically in group theory , a group is said to be perfect if it equals its own commutator subgroup , or equivalently, if the group has no non-trivial abelian quotients .
The smallest (non-trivial) perfect group is the alternating group A 5 . More generally, any non-abelian simple group is perf... | https://en.wikipedia.org/wiki/Perfect_group |
In economics , perfect information (sometimes referred to as "no hidden information") is a feature of perfect competition . With perfect information in a market, all consumers and producers have complete and instantaneous knowledge of all market prices, their own utility, and own cost functions.
In game theory , a seq... | https://en.wikipedia.org/wiki/Perfect_information |
Perfect mixing is a term heavily used in relation to the definition of models that predict the behavior of chemical reactors . Perfect mixing assumes that there are no spatial gradients in a given physical envelope , such as:
This physical chemistry -related article is a stub . You can help Wikipedia by expanding it . | https://en.wikipedia.org/wiki/Perfect_mixing |
In game theory , perfect recall is a property of players within extensive-form games , introduced by Harold W. Kuhn in 1953. [ 1 ] it describes a player's ability to remember their past actions and the information they possessed at previous decision points. [ 2 ] [ 3 ] For example, in a simplified card game where a pla... | https://en.wikipedia.org/wiki/Perfect_recall_(game_theory) |
A perfect ruler of length ℓ {\displaystyle \ell } is a ruler with integer markings a 1 = 0 < a 2 < ⋯ < a n = ℓ {\displaystyle a_{1}=0<a_{2}<\dots <a_{n}=\ell } , for which there exists an integer m {\displaystyle m} such that any positive integer k ≤ m {\displaystyle k\leq m} is uniquely expressed as the difference k =... | https://en.wikipedia.org/wiki/Perfect_ruler |
In general topology , a subset of a topological space is perfect if it is closed and has no isolated points . Equivalently: the set S {\displaystyle S} is perfect if S = S ′ {\displaystyle S=S'} , where S ′ {\displaystyle S'} denotes the set of all limit points of S {\displaystyle S} , also known as the derived set of ... | https://en.wikipedia.org/wiki/Perfect_set |
Perfluoro(2-methyl-3-pentanone) is a fluorinated ketone with the structural formula CF 3 CF 2 C(=O)CF(CF 3 ) 2 , a fully-fluorinated analog of ethyl isopropyl ketone . It is used as an electronics coolant liquid and fire protection fluid sold commercially by 3M under brand names such as Novec 1230 , Novec 649 , and FK-... | https://en.wikipedia.org/wiki/Perfluoro(2-methyl-3-pentanone) |
Perfluorocarbon emulsions are emulsions containing either bubbles or droplets which have perfluorocarbons inside them. Some of them are commonly used in medicine as ultrasound contrast agents, and others have been studied for use as oxygen therapeutics.
The most common use of perfluorocarbon emulsions is as ultrasound... | https://en.wikipedia.org/wiki/Perfluorocarbon_emulsions |
Perfluorocarbon tracers (PFTs) are a range of perfluorocarbons used in flow tracers and other tracing applications. They are used by releasing the PFT at a certain point, and determining the concentration of that PFT at another set of points, allowing the flow from the source to the points to be determined.
PFTs are b... | https://en.wikipedia.org/wiki/Perfluorocarbon_tracer |
Perfluorodecyltrichlorosilane , also known as FDTS , is a colorless liquid chemical with molecular formula C 10 H 4 Cl 3 F 17 Si . FDTS molecules form self-assembled monolayers . They form covalent silicon–oxygen bonds to free hydroxyl (–OH) groups, such as the surfaces of glass, ceramics, or silica .
Due to its heavi... | https://en.wikipedia.org/wiki/Perfluorodecyltrichlorosilane |
Perfluorohexane ( C 6 F 14 ), or tetradecafluorohexane , is a fluorocarbon . It is a derivative of hexane in which all the hydrogen atoms are replaced by fluorine atoms. It is used in one formulation of the electronic cooling liquid/insulator Fluorinert for low-temperature applications due to its low boiling point of 5... | https://en.wikipedia.org/wiki/Perfluorohexane |
Perfluorohexanesulfonic acid ( PFHxS ) ( conjugate base perfluorohexanesulfonate ) is a synthetic chemical compound . It is one of many compounds collectively known as per- and polyfluoroalkyl substances (PFASs). It is an anionic fluorosurfactant and a persistent organic pollutant with bioaccumulative properties. Altho... | https://en.wikipedia.org/wiki/Perfluorohexanesulfonic_acid |
Perfluorooctanesulfonic acid ( PFOS ) ( conjugate base perfluorooctanesulfonate ) is a chemical compound having an eight- carbon fluorocarbon chain and a sulfonic acid functional group , and thus it is a perfluorosulfonic acid and a perfluoroalkyl substance (PFAS). It is an anthropogenic (man-made) fluorosurfactant , n... | https://en.wikipedia.org/wiki/Perfluorooctanesulfonic_acid |
Perfluorooctanesulfonyl fluoride ( POSF ) is a synthetic perfluorinated compound with a sulfonyl fluoride functional group . It is used to make perfluorooctanesulfonic acid (PFOS) and PFOS-based compounds. These compounds have a variety of industrial and consumer uses, but POSF-derived substances ultimately degrade to ... | https://en.wikipedia.org/wiki/Perfluorooctanesulfonyl_fluoride |
Perfluorooctanoic acid ( PFOA ; conjugate base perfluorooctanoate ; also known colloquially as C8 , from its chemical formula C 8 HF 15 O 2 ) is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes and as a chemical precursor. PFOA is considered a surfactant, or... | https://en.wikipedia.org/wiki/Perfluorooctanoic_acid |
Perfluorotributylamine ( PFTBA ), also referred to as FC43, is an organic compound with the chemical formula N(CF 2 CF 2 CF 2 CF 3 ) 3 . It is a colorless liquid. A molecule of this chemical compound consists of three butyl groups connected to one nitrogen atom , in which all of the hydrogen atoms are replaced with flu... | https://en.wikipedia.org/wiki/Perfluorotributylamine |
In March 2013, Lockheed Martin announced that it was developing a family of membranes made from graphene , under the trademark Perforene .
The most promising application is seawater desalination . With holes as small as one nanometer in diameter, the membranes would trap sodium, chlorine and other ions, while allowing... | https://en.wikipedia.org/wiki/Perforene |
Performance-Based Building Design is an approach to the design of any complexity of building, from single-detached homes up to and including high-rise apartments and office buildings. A building constructed in this way is required to meet certain measurable or predictable performance requirements, such as energy effici... | https://en.wikipedia.org/wiki/Performance-based_building_design |
Performance-enhancing proxies ( PEPs ) are network agents designed to improve the end-to-end performance of some communication protocols . PEP standards are defined in RFC 3135 (PEPs intended to mitigate link-related degradations) and RFC 3449 (TCP performance implications of network path asymmetry).
Available PEP imp... | https://en.wikipedia.org/wiki/Performance-enhancing_proxy |
Performance Analyzer is a commercial utility software for software performance analysis for x86 or SPARC machines. It has both a graphical user interface [ 2 ] and a command line interface . It is available for both Linux and Solaris operating systems. It can profile C, C++, and Java . [ 3 ]
Performance Analyzer is av... | https://en.wikipedia.org/wiki/Performance_Analyzer |
The PR ( performance rating , P-rating , or Pentium rating ) system was a figure of merit developed by AMD , Cyrix , IBM Microelectronics and SGS-Thomson in the mid-1990s as a method of comparing their x86 processors to those of rival Intel . The idea was to consider instructions per cycle (IPC) in addition to the cloc... | https://en.wikipedia.org/wiki/Performance_Rating |
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