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The photoacoustic effect or optoacoustic effect is the formation of sound waves following light absorption in a material sample. In order to obtain this effect the light intensity must vary, either periodically ( modulated light ) or as a single flash ( pulsed light ). [ 1 ] [ page needed ] [ 2 ] The photoacoustic effe... | https://en.wikipedia.org/wiki/Photoacoustic_effect |
Photoacoustic microscopy is an imaging method based on the photoacoustic effect and is a subset of photoacoustic tomography . Photoacoustic microscopy takes advantage of the local temperature rise that occurs as a result of light absorption in tissue. Using a nanosecond pulsed laser beam, tissues undergo thermoelastic ... | https://en.wikipedia.org/wiki/Photoacoustic_microscopy |
Photoacoustic spectroscopy is the measurement of the effect of absorbed electromagnetic energy (particularly of light ) on matter by means of acoustic detection. The discovery of the photoacoustic effect dates to 1880 when Alexander Graham Bell showed that thin discs emitted sound when exposed to a beam of sunlight tha... | https://en.wikipedia.org/wiki/Photoacoustic_spectroscopy |
Photoactivatable fluorescent proteins (PAFPs) is a type of fluorescent protein that exhibit fluorescence that can be modified by a light-induced chemical reaction .
The first PAFP, Kaede (protein) , was isolated from Trachyphyllia geoffroyi in a cDNA library screen designed to identify new fluorescent proteins. [ 1 ] ... | https://en.wikipedia.org/wiki/Photoactivatable_fluorescent_protein |
Photoactivatable probes , or caged probes , are cellular players ( proteins , nucleic acids , small molecules ) that can be triggered by a flash of light. They are used in biological research to study processes in cells. The basic principle is to bring a photoactivatable agent (e.g. a small molecule modified with a lig... | https://en.wikipedia.org/wiki/Photoactivatable_probes |
Photoactivated adenylyl cyclase (PAC) is a protein consisting of an adenylyl cyclase enzyme domain directly linked to a BLUF (blue light receptor using FAD) type light sensor domain. When illuminated with blue light, the enzyme domain becomes active and converts ATP to cAMP , an important second messenger in many cells... | https://en.wikipedia.org/wiki/Photoactivated_adenylyl_cyclase |
Photo-activated localization microscopy ( PALM or FPALM ) [ 1 ] [ 2 ] and stochastic optical reconstruction microscopy (STORM) [ 3 ] are widefield (as opposed to point scanning techniques such as laser scanning confocal microscopy ) fluorescence microscopy imaging methods that allow obtaining images with a resolution b... | https://en.wikipedia.org/wiki/Photoactivated_localization_microscopy |
Photoaffinity labeling is a chemoproteomics technique used to attach "labels" to the active site of a large molecule, especially a protein . The "label" attaches to the molecule loosely and reversibly, and has an inactive site which can be converted using photolysis into a highly reactive form, which causes the label t... | https://en.wikipedia.org/wiki/Photoaffinity_labeling |
Photoanalysis (or photo analysis) refers to the study of pictures to compile various types of data, for example, to measure the size distribution of virtually anything that can be captured by photo. Photoanalysis technology has changed the way mines and mills quantify fragmented material.
Images are a good way to doc... | https://en.wikipedia.org/wiki/Photoanalysis |
In botany , a photoassimilate is one of a number of biological compounds formed by assimilation using light-dependent reactions . This term is most commonly used to refer to the energy-storing monosaccharides produced by photosynthesis in the leaves of plants. [ 1 ]
Only NADPH, ATP and water are made in the "light" re... | https://en.wikipedia.org/wiki/Photoassimilate |
Photoautotrophs are organisms that can utilize light energy from sunlight and elements (such as carbon ) from inorganic compounds to produce organic materials needed to sustain their own metabolism (i.e. autotrophy ). Such biological activities are known as photosynthesis , and examples of such organisms include plants... | https://en.wikipedia.org/wiki/Photoautotroph |
Photobiology is the scientific study of the beneficial and harmful interactions of light (technically, non-ionizing radiation ) in living organisms . [ 1 ] The field includes the study of photophysics, photochemistry, photosynthesis , photomorphogenesis , visual processing , circadian rhythms , photomovement, biolumine... | https://en.wikipedia.org/wiki/Photobiology |
A photobioreactor (PBR) refers to any cultivation system designed for growing photoautotrophic organisms using artificial light sources or solar light to facilitate photosynthesis. Photobioreactors are typically used to cultivate microalgae , cyanobacteria , and some mosses . [ 1 ] Photobioreactors can be open systems,... | https://en.wikipedia.org/wiki/Photobioreactor |
Photobiotin is a derivative of biotin used as a biochemical tool. It is composed of a biotin group, a linker group, and a photoactivatable aryl azide group.
The photoactivatable group provides nonspecific labeling of proteins, DNA and RNA probes or other molecules. Biotinylation of DNA and RNA with photoactivatable b... | https://en.wikipedia.org/wiki/Photobiotin |
Photoblasticism is a mechanism of seed dormancy . Photoblastic seeds require light in order to germinate . [ 2 ] Once germination starts, the stored nutrients that have accumulated during maturation start to be digested which then supports cell expansion and overall growth. [ 3 ] Within light-stimulated germination, Ph... | https://en.wikipedia.org/wiki/Photoblasticism |
In optics , photobleaching (sometimes termed fading) is the photochemical alteration of a dye or a fluorophore molecule such that it is permanently unable to fluoresce. This is caused by cleaving of covalent bonds or non-specific reactions between the fluorophore and surrounding molecules. [ 1 ] [ 2 ] Such irreversible... | https://en.wikipedia.org/wiki/Photobleaching |
A photocarcinogen is a substance which causes cancer when an organism is exposed to it, then illuminated. Many chemicals that are not carcinogenic can be photocarcinogenic when combined with exposure to light, especially UV . This can easily be understood from a photochemical perspective: The reactivity of a chemical... | https://en.wikipedia.org/wiki/Photocarcinogen |
In chemistry , photocatalysis is the acceleration of a photoreaction in the presence of a photocatalyst , the excited state of which "repeatedly interacts with the reaction partners forming reaction intermediates and regenerates itself after each cycle of such interactions." [ 1 ] In many cases, the catalyst is a solid... | https://en.wikipedia.org/wiki/Photocatalysis |
Photocatalyst activity indicator ink ( paii ) is a substance used to identify the presence of an underlying heterogeneous photocatalyst and to measure its activity. Such inks render visible the activity of photocatalytic coatings applied to various "self-cleaning" products. The inks contain a dyestuff that reacts to ul... | https://en.wikipedia.org/wiki/Photocatalyst_activity_indicator_ink |
Photocatalytic water splitting is a process that uses photocatalysis for the dissociation of water (H 2 O) into hydrogen ( H 2 ) and oxygen ( O 2 ). The inputs are light energy ( photons ), water, and a catalyst (s). The process is inspired by Photosynthesis , which converts water and carbon dioxide into oxygen and ca... | https://en.wikipedia.org/wiki/Photocatalytic_water_splitting |
A photocathode is a surface engineered to convert light ( photons ) into electrons using the photoelectric effect . Photocathodes are important in accelerator physics where they are utilised in a photoinjector to generate high brightness electron beams. Electron beams generated with photocathodes are commonly used fo... | https://en.wikipedia.org/wiki/Photocathode |
The Photochemical Reflectance Index ( PRI ) is a reflectance measurement developed by John Gamon during his tenure as a postdoctorate fellow supervised by Christopher Field at the Carnegie Institution for Science at Stanford University. The PRI is sensitive to changes in carotenoid pigments (e.g. xanthophyll pigments) ... | https://en.wikipedia.org/wiki/Photochemical_Reflectance_Index |
Photochemical action plots are a scientific tool used to understand the effects of different wavelengths of light on photochemical reactions . The methodology involves exposing a reaction solution to the same number of photons at varying monochromatic wavelengths, monitoring the conversion or reaction yield of starting... | https://en.wikipedia.org/wiki/Photochemical_action_plots |
A photochemical logic gate is based on the photochemical intersystem crossing and molecular electronic transition between photochemically active molecules, leading to logic gates that can be produced. [ 1 ]
The OR gate is based on the activation of molecule A, and thus pass electron / photon to molecule C's excited st... | https://en.wikipedia.org/wiki/Photochemical_logic_gate |
Photochemical reduction of carbon dioxide harnesses solar energy to convert CO 2 into higher-energy products. Environmental interest in producing artificial systems is motivated by recognition that CO 2 is a greenhouse gas . The process has not been commercialized.
Photochemical reduction involves chemical reduction ... | https://en.wikipedia.org/wiki/Photochemical_reduction_of_carbon_dioxide |
Photochemistry is the branch of chemistry concerned with the chemical effects of light. Generally, this term is used to describe a chemical reaction caused by absorption of ultraviolet ( wavelength from 100 to 400 nm ), visible (400–750 nm), or infrared radiation (750–2500 nm). [ 1 ]
In nature, photochemistry is of im... | https://en.wikipedia.org/wiki/Photochemistry |
Photochlorination is a chlorination reaction that is initiated by light. Usually a C-H bond is converted to a C-Cl bond. Photochlorination is carried out on an industrial scale. The process is exothermic and proceeds as a chain reaction initiated by the homolytic cleavage of molecular chlorine into chlorine radicals b... | https://en.wikipedia.org/wiki/Photochlorination |
A photochromic lens is an optical lens that darkens on exposure to light of sufficiently high frequency, most commonly ultraviolet (UV) radiation. In the absence of activating light, the lenses return to their clear state. Photochromic lenses may be made of polycarbonate , or another plastic . Glass lenses use visible... | https://en.wikipedia.org/wiki/Photochromic_lens |
Photochromism is the reversible change of color upon exposure to light. It is a transformation of a chemical species ( photoswitch ) between two forms through the absorption of electromagnetic radiation ( photoisomerization ), where each form has a different absorption spectrum. [ 1 ] [ 2 ] This reversible structural o... | https://en.wikipedia.org/wiki/Photochromism |
Photoconductive atomic force microscopy ( PC-AFM ) is a variant of atomic force microscopy that measures photoconductivity in addition to surface forces.
Multi-layer photovoltaic cells have gained popularity since mid 1980s. [ 1 ] At the time, research was primarily focused on single-layer photovoltaic (PV) devices be... | https://en.wikipedia.org/wiki/Photoconductive_atomic_force_microscopy |
Photoconductive polymers absorb electromagnetic radiation and produce an increase of electrical conductivity . Photoconductive polymers have been used in a wide variety of technical applications such as Xerography (electrophotography) and laser printing . Electrical conductivity is usually very small in organic compoun... | https://en.wikipedia.org/wiki/Photoconductive_polymer |
Photoconductivity is an optical and electrical phenomenon in which a material becomes more electrically conductive due to the absorption of electromagnetic radiation such as visible light , ultraviolet light, infrared light, or gamma radiation . [ 1 ]
When light is absorbed by a material such as a semiconductor , the ... | https://en.wikipedia.org/wiki/Photoconductivity |
A photocyte is a cell that specializes in catalyzing enzymes to produce light ( bioluminescence ). [ 1 ] Photocytes typically occur in select layers of epithelial tissue, functioning singly or in a group, or as part of a larger apparatus (a photophore ). They contain special structures called photocyte granules. These ... | https://en.wikipedia.org/wiki/Photocyte |
Photodegradation is the alteration of materials by light. Commonly, the term is used loosely to refer to the combined action of sunlight and air , which cause oxidation and hydrolysis . Often photodegradation is intentionally avoided, since it destroys paintings and other artifacts. It is, however, partly responsible f... | https://en.wikipedia.org/wiki/Photodegradation |
Photodisintegration (also called phototransmutation , or a photonuclear reaction ) is a nuclear process in which an atomic nucleus absorbs a high-energy gamma ray , enters an excited state, and immediately decays by emitting a subatomic particle. The incoming gamma ray effectively knocks one or more neutrons , protons ... | https://en.wikipedia.org/wiki/Photodisintegration |
Photodissociation , photolysis , photodecomposition , or photofragmentation is a chemical reaction in which molecules of a chemical compound are broken down by absorption of light or photons . It is defined as the interaction of one or more photons with one target molecule that dissociates into two fragments. [ 1 ]
He... | https://en.wikipedia.org/wiki/Photodissociation |
In astrophysics , photodissociation regions (or photon-dominated regions , PDRs ) are predominantly neutral regions of the interstellar medium in which far ultraviolet photons strongly influence the gas chemistry and act as the most important source of heat. [ 2 ] They constitute a sort of shell around sources of far-U... | https://en.wikipedia.org/wiki/Photodissociation_region |
In materials science , photoelasticity describes changes in the optical properties of a material under mechanical deformation . It is a property of all dielectric media and is often used to experimentally determine the stress distribution in a material.
The photoelastic phenomenon was first discovered by the Scottish ... | https://en.wikipedia.org/wiki/Photoelasticity |
The photoelectric effect is the emission of electrons from a material caused by electromagnetic radiation such as ultraviolet light . Electrons emitted in this manner are called photoelectrons. The phenomenon is studied in condensed matter physics , solid state , and quantum chemistry to draw inferences about the prope... | https://en.wikipedia.org/wiki/Photoelectric_effect |
Flame photometry is a type of atomic emission spectroscopy . It is also known as flame emission spectroscopy . [ 1 ] [ 2 ] A photoelectric flame photometer is an instrument used in inorganic chemical analysis to determine the concentration of certain metal ions, among them sodium , potassium , lithium , and calcium . [... | https://en.wikipedia.org/wiki/Photoelectric_flame_photometer |
A " photoelectrochemical cell " is one of two distinct classes of device. The first produces electrical energy similarly to a dye-sensitized photovoltaic cell , which meets the standard definition of a photovoltaic cell . The second is a photoelectrolytic cell , that is, a device which uses light incident on a photose... | https://en.wikipedia.org/wiki/Photoelectrochemical_cell |
A " photoelectrochemical cell " is one of two distinct classes of device. The first produces electrical energy similarly to a dye-sensitized photovoltaic cell , which meets the standard definition of a photovoltaic cell . The second is a photoelectrolytic cell , that is, a device which uses light incident on a photose... | https://en.wikipedia.org/wiki/Photoelectrochemical_oxidation |
Photoelectrochemical processes are processes in photoelectrochemistry ; they usually involve transforming light into other forms of energy. [ 1 ] These processes apply to photochemistry, optically pumped lasers , sensitized solar cells , luminescence , and photochromism .
Electron excitation is the movement of an elec... | https://en.wikipedia.org/wiki/Photoelectrochemical_process |
Photoelectrochemical reduction of carbon dioxide , also known as photoelectrolysis of carbon dioxide , is a chemical process whereby carbon dioxide is reduced to carbon monoxide or hydrocarbons by the energy of incident light. This process requires catalysts , most of which are semiconducting materials . The feasibilit... | https://en.wikipedia.org/wiki/Photoelectrochemical_reduction_of_carbon_dioxide |
Photoelectrochemistry is a subfield of study within physical chemistry concerned with the interaction of light with electrochemical systems . [ 1 ] [ 2 ] It is an active domain of investigation. One of the pioneers of this field of electrochemistry was the German electrochemist Heinz Gerischer . The interest in this do... | https://en.wikipedia.org/wiki/Photoelectrochemistry |
Photoelectrolysis of water , also known as photoelectrochemical water splitting , occurs in a photoelectrochemical cell when light is used as the energy source for the electrolysis of water, producing dihydrogen which can be used as a fuel. This process is one route to a " hydrogen economy ", in which hydrogen fuel is ... | https://en.wikipedia.org/wiki/Photoelectrolysis_of_water |
Photoelectron photoion coincidence spectroscopy ( PEPICO ) is a combination of photoionization mass spectrometry and photoelectron spectroscopy . [ 1 ] It is largely based on the photoelectric effect . Free molecules from a gas-phase sample are ionized by incident vacuum ultraviolet (VUV) radiation. In the ensuing pho... | https://en.wikipedia.org/wiki/Photoelectron_photoion_coincidence_spectroscopy |
In chronobiology , photoentrainment refers to the process by which an organism's biological clock, or circadian rhythm , synchronizes to daily cycles of light and dark in the environment. The mechanisms of photoentrainment differ from organism to organism. [ 1 ] Photoentrainment plays a major role in maintaining proper... | https://en.wikipedia.org/wiki/Photoentrainment_(chronobiology) |
Photoexcitation is the production of an excited state of a quantum system by photon absorption. The excited state originates from the interaction between a photon and the quantum system . Photons carry energy that is determined by the wavelengths of the light that carries the photons. [ 1 ] Objects that emit light with... | https://en.wikipedia.org/wiki/Photoexcitation |
Photofermentation is the fermentative conversion of organic substrate to biohydrogen manifested by a diverse group of photosynthetic bacteria by a series of biochemical reactions involving three steps similar to anaerobic conversion . Photofermentation differs from dark fermentation because it only proceeds in the pres... | https://en.wikipedia.org/wiki/Photofermentation |
Photofission is a process in which a nucleus , after absorbing a gamma ray , undergoes nuclear fission and splits into two or more fragments.
The reaction was discovered in 1940 by a small team of engineers and scientists operating the Westinghouse Atom Smasher at the company's Research Laboratories in Forest Hills, P... | https://en.wikipedia.org/wiki/Photofission |
Photofragment ion imaging or, more generally, Product Imaging is an experimental technique for making measurements of the velocity of product molecules or particles following a chemical reaction or the photodissociation of a parent molecule. [ 1 ] The method uses a two-dimensional detector, usually a microchannel plate... | https://en.wikipedia.org/wiki/Photofragment-ion_imaging |
Photogeochemistry merges photochemistry and geochemistry into the study of light-induced chemical reactions that occur or may occur among natural components of Earth's surface. The first comprehensive review on the subject was published in 2017 by the chemist and soil scientist Timothy A Doane, [ 1 ] but the term photo... | https://en.wikipedia.org/wiki/Photogeochemistry |
Photoglottography or photo-electric glottography is a laboratory technique for investigating the opening and closing of the glottis in the larynx . It detects variations in the amount of light that can pass through the glottis as it opens and closes. [ 1 ]
It was observed by Czermak in 1861 that the inside of the trac... | https://en.wikipedia.org/wiki/Photoglottography |
Photografting is a technique used in the study of polymers and more in specific polymeric biomaterials . Technically speaking it is the covalent incorporation of functional additives to a polymer matrix or polymer surface using a light-induced mechanism. It is an important technique for the modification of biomaterial ... | https://en.wikipedia.org/wiki/Photografting |
Photographic processing or photographic development is the chemical means by which photographic film or paper is treated after photographic exposure to produce a negative or positive image . Photographic processing transforms the latent image into a visible image, makes this permanent and renders it insensitive to ligh... | https://en.wikipedia.org/wiki/Photographic_laboratory |
Photographic magnitude ( m ph or m p ) is a measure of the relative brightness of a star or other astronomical object as imaged on a photographic film emulsion with a camera attached to a telescope . An object's apparent photographic magnitude depends on its intrinsic luminosity , its distance and any extinction of lig... | https://en.wikipedia.org/wiki/Photographic_magnitude |
Photoheterotrophs ( Gk : photo = light, hetero = (an)other, troph = nourishment) are heterotrophic phototrophs —that is, they are organisms that use light for energy, but cannot use carbon dioxide as their sole carbon source. Consequently, they use organic compounds from the environment to satisfy their carbon requirem... | https://en.wikipedia.org/wiki/Photoheterotroph |
In photochemistry , photohydrogen is hydrogen produced with the help of artificial or natural light . This is how the leaf of a tree splits water molecules into protons (hydrogen ions), electrons (to make carbohydrates ) and oxygen (released into the air as a waste product). [ 1 ] Photohydrogen may also be produced by ... | https://en.wikipedia.org/wiki/Photohydrogen |
Photoinduced charge separation is the process of an electron in an atom or molecule, being excited to a higher energy level by the absorption of a photon and then leaving the atom or molecule to free space, or to a nearby electron acceptor . [ 1 ]
An atom consists of a positively-charged nucleus surrounded by bound el... | https://en.wikipedia.org/wiki/Photoinduced_charge_separation |
Photoinduced electron transfer ( PET ) is an excited state electron transfer process by which an excited electron is transferred from donor to acceptor. [ 1 ] [ 2 ] Due to PET a charge separation is generated, i.e. , redox reaction takes place in excited state (this phenomenon is not observed in Dexter electron transfe... | https://en.wikipedia.org/wiki/Photoinduced_electron_transfer |
Photoinduced phase transition is a technique used in solid-state physics . It is a process to the nonequilibrium phases generated from an equilibrium by shining on high energy photons , and the nonequilibrium phase is a macroscopic excited domain that has new structural and electronic orders quite different from the st... | https://en.wikipedia.org/wiki/Photoinduced_phase_transitions |
Photoinhibition is light-induced reduction in the photosynthetic capacity of a plant , alga , or cyanobacterium . Photosystem II (PSII) is more sensitive to light than the rest of the photosynthetic machinery, and most researchers define the term as light-induced damage to PSII. In living organisms, photoinhibited PSII... | https://en.wikipedia.org/wiki/Photoinhibition |
In chemistry , a photoinitiator is a molecule that creates reactive species ( free radicals , cations or anions ) when exposed to radiation ( UV or visible ). Synthetic photoinitiators are key components in photopolymers (for example, photo-curable coatings, adhesives and dental restoratives).
Some small molecules in ... | https://en.wikipedia.org/wiki/Photoinitiator |
Photoionisation cross section in the context of condensed matter physics refers to the probability of a particle (usually an electron ) being emitted from its electronic state .
The photoemission is a useful experimental method for the determination and the study of the electronic states. Sometimes the small amount of... | https://en.wikipedia.org/wiki/Photoionisation_cross_section |
Photoionization is the physical process in which an ion is formed from the interaction of a photon with an atom or molecule . [ 2 ]
Not every interaction between a photon and an atom, or molecule, will result in photoionization. The probability of photoionization is related to the photoionization cross section of the ... | https://en.wikipedia.org/wiki/Photoionization |
A photoionization detector or PID is a type of gas detector .
Typical photoionization detectors measure volatile organic compounds and other gases in concentrations from sub parts per billion to 10 000 parts per million (ppm). The photoionization detector is an efficient and inexpensive detector for many gas and vapor... | https://en.wikipedia.org/wiki/Photoionization_detector |
In chemistry , photoisomerization is a form of isomerization induced by photoexcitation. [ 2 ] Both reversible and irreversible photoisomerizations are known for photoswitchable compounds. The term "photoisomerization" usually, however, refers to a reversible process.
Photoisomerization of the compound retinal in the ... | https://en.wikipedia.org/wiki/Photoisomerization |
Photokinesis is a change in the velocity of movement of an organism as a result of changes in light intensity. [ 1 ] The alteration in speed is independent of the direction from which the light is shining. Photokinesis is described as positive if the velocity of travel is greater with an increase in light intensity and... | https://en.wikipedia.org/wiki/Photokinesis |
A photolabile protecting group ( PPG ; also known as: photoremovable, photosensitive, or photocleavable protecting group ) is a chemical modification to a molecule that can be removed with light . PPGs enable high degrees of chemoselectivity as they allow researchers to control spatial, temporal and concentration varia... | https://en.wikipedia.org/wiki/Photolabile_protecting_group |
Photolithography (also known as optical lithography ) is a process used in the manufacturing of integrated circuits . It involves using light to transfer a pattern onto a substrate, typically a silicon wafer .
The process begins with a photosensitive material, called a photoresist , being applied to the substrate. A p... | https://en.wikipedia.org/wiki/Photolithography |
Photoluminescence (abbreviated as PL ) is light emission from any form of matter after the absorption of photons (electromagnetic radiation). [ 1 ] It is one of many forms of luminescence (light emission) and is initiated by photoexcitation (i.e. photons that excite electrons to a higher energy level in an atom), hence... | https://en.wikipedia.org/wiki/Photoluminescence |
Photoluminescence excitation (abbreviated PLE ) is a specific type of photoluminescence and concerns the interaction between electromagnetic radiation and matter . It is used in spectroscopic measurements where the frequency of the excitation light is varied, and the luminescence is monitored at the typical emission fr... | https://en.wikipedia.org/wiki/Photoluminescence_excitation |
Photomagnetism ( photomagnetic effect ) is the effect in which a material acquires (and in some cases loses) its ferromagnetic properties in response to light. The current model for this phenomenon is a light-induced electron transfer , accompanied by the reversal of the spin direction of an electron . This leads to an... | https://en.wikipedia.org/wiki/Photomagnetism |
A photomask (also simply called a mask ) is an opaque plate with transparent areas that allow light to shine through in a defined pattern. Photomasks are commonly used in photolithography for the production of integrated circuits (ICs or "chips") to produce a pattern on a thin wafer of material (usually silicon ). In s... | https://en.wikipedia.org/wiki/Photomask |
Photomath is an educational technology mobile app, owned by Google . It features a computer algebra system with an augmented optical character recognition system, designed for use with a smartphone's camera to scan and recognize mathematical equations; the app then displays step-by-step explanations onscreen. [ 4 ]
Th... | https://en.wikipedia.org/wiki/Photomath |
Photomechanical effect is the change in the shape of a material when it is exposed to light . This effect was first documented by Alexander Graham Bell in 1880. [ 1 ] Kenji Uchino demonstrated that a photostrictive material could be used for legs in the construction of a miniature optically-powered "walker". [ 2 ]
The... | https://en.wikipedia.org/wiki/Photomechanical_effect |
Photometric parallax is a means to infer the distances of stars using their colours and apparent brightnesses. It was used by the Sloan Digital Sky Survey to discover the Virgo super star cluster .
Assuming that a star is on the main sequence, the star's absolute magnitude can be determined based on its color. Once th... | https://en.wikipedia.org/wiki/Photometric_parallax |
In astronomy , photometry , from Greek photo- ("light") and -metry ("measure"), is a technique used in astronomy that is concerned with measuring the flux or intensity of light radiated by astronomical objects . [ 1 ] This light is measured through a telescope using a photometer , often made using electronic devices su... | https://en.wikipedia.org/wiki/Photometry_(astronomy) |
In physics , photon-induced electric field poling is a phenomenon whereby a pattern of local electric field orientations can be encoded in a suitable ferroelectric material , such as perovskite . The resulting encoded material is conceptually similar to the pattern of magnetic field orientations within the magnetic dom... | https://en.wikipedia.org/wiki/Photon-induced_electric_field_poling |
2. Measurement of the number and spatial distribution of photons produced in particle collisions
Photon Multiplicity Detector (PMD) is a detector used in the measurement of the multiplicity and spatial distribution of photons produced in nucleus - nucleus collisions. In short form, it is denoted by PMD. [ 1 ] [ 2 ] It... | https://en.wikipedia.org/wiki/Photon_Multiplicity_Detector |
A photon bubble is a type of radiation-driven instability that can occur in the magnetized, radiation-supported gas surrounding neutron stars , black hole accretion disks or at the edge of ultra-compact HII regions around young, massive stars . [ 1 ] [ 2 ] [ 3 ] The instability occurs as follows. A compressive magnetoh... | https://en.wikipedia.org/wiki/Photon_bubble |
Photon diffusion equation is a second order partial differential equation describing the time behavior of photon fluence rate distribution in a low-absorption high-scattering medium.
Its mathematical form is as follows. ∇ ( D ( r ) ⋅ ∇ ) Φ ( r → , t ) − v μ a ( r → ) Φ ( r → , t ) + v S ( r → , t ) = ∂ Φ ( r → , t ) ∂... | https://en.wikipedia.org/wiki/Photon_diffusion_equation |
In physics, a photon gas is a gas -like collection of photons , which has many of the same properties of a conventional gas like hydrogen or neon – including pressure, temperature, and entropy. The most common example of a photon gas in equilibrium is the black-body radiation .
Photons are part of a family of particle... | https://en.wikipedia.org/wiki/Photon_gas |
Photon polarization is the quantum mechanical description of the classical polarized sinusoidal plane electromagnetic wave . An individual photon can be described as having right or left circular polarization , or a superposition of the two. Equivalently, a photon can be described as having horizontal or vertical linea... | https://en.wikipedia.org/wiki/Photon_polarization |
The photon underproduction crisis is a cosmological discussion concerning the purported deficit between observed photons and predicted photons. [ 1 ] [ 2 ]
The deficit, or underproduction crisis, is a theoretical problem, arising from comparing observations of ultraviolet light emitted from known populations of galaxi... | https://en.wikipedia.org/wiki/Photon_underproduction_crisis |
A photonic crystal is an optical nanostructure in which the refractive index changes periodically. This affects the propagation of light in the same way that the structure of natural crystals gives rise to X-ray diffraction and that the atomic lattices (crystal structure) of semiconductors affect their conductivity of ... | https://en.wikipedia.org/wiki/Photonic_crystal |
A photonic metamaterial ( PM ), also known as an optical metamaterial , is a type of electromagnetic metamaterial , that interacts with light, covering terahertz ( THz ), infrared (IR) or visible wavelengths . [ 1 ] The materials employ a periodic , cellular structure.
The subwavelength periodicity [ 2 ] distinguishes... | https://en.wikipedia.org/wiki/Photonic_metamaterial |
Photonics Society of Poland ( Polish : Polskie Stowarzyszenie Fotoniczne, PSP ) is the largest optics / optoelectronics / photonics organization in Poland . It was transformed from the SPIE Poland Chapter on October 18, 2007 during the Extraordinary General Meeting of the SPIE Poland Chapter members.
PSP is a publishe... | https://en.wikipedia.org/wiki/Photonics_Society_of_Poland |
Photonics and Nanostructures: Fundamentals and Applications is a peer-reviewed scientific journal , published quarterly by Elsevier . The editors-in-chief are A. Di Falco University of St Andrews , M. Lapine University of Technology Sydney , P. Tassin Chalmers University of Technology , M. Vanwolleghem Centre National ... | https://en.wikipedia.org/wiki/Photonics_and_Nanostructures:_Fundamentals_and_Applications |
A photooxygenation is a light-induced oxidation reaction in which molecular oxygen is incorporated into the product(s). [ 1 ] [ 2 ] Initial research interest in photooxygenation reactions arose from Oscar Raab's observations in 1900 that the combination of light, oxygen and photosensitizers is highly toxic to cells. [ ... | https://en.wikipedia.org/wiki/Photooxygenation |
Photoperiod is the change of day length around the seasons. The rotation of the earth around its axis produces 24 hour changes in light (day) and dark (night) cycles on earth. The length of the light and dark in each phase varies across the seasons due to the tilt of the earth around its axis . The photoperiod defines ... | https://en.wikipedia.org/wiki/Photoperiodism |
Photopharmacology is an emerging multidisciplinary field that combines photochemistry and pharmacology . [ 1 ] Built upon the ability of light to change the pharmacokinetics and pharmacodynamics of bioactive molecules, it aims at regulating the activity of drugs in vivo by using light. [ 2 ] The light-based modulation ... | https://en.wikipedia.org/wiki/Photopharmacology |
In biology , photophobia (adjective: photophobic ) is negative response to light.
Photophobia is a behavior demonstrated by insects or other animals which seek to stay out of the light.
In botany , the term photophobia/photophobic describes shade-loving plants (sciophytes) that thrive in low light conditions. [ 1 ]
... | https://en.wikipedia.org/wiki/Photophobia_(biology) |
A photophore is a glandular organ that appears as luminous spots on marine animals, including fish and cephalopods . The organ can be simple, or as complex as the human eye, equipped with lenses, shutters, color filters, and reflectors; unlike an eye, however, it is optimized to produce light, not absorb it. [ 1 ]
The... | https://en.wikipedia.org/wiki/Photophore |
Photophoresis denotes the phenomenon that small particles suspended in gas (aerosols) or liquids (hydrocolloids) start to migrate when illuminated by a sufficiently intense beam of light . The existence of this phenomenon is owed to a non-uniform distribution of temperature of an illuminated particle in a fluid medium... | https://en.wikipedia.org/wiki/Photophoresis |
In the process of photosynthesis , the phosphorylation of ADP to form ATP using the energy of sunlight is called photophosphorylation . Cyclic photophosphorylation occurs in both aerobic and anaerobic conditions, driven by the main primary source of energy available to living organisms, which is sunlight. All organisms... | https://en.wikipedia.org/wiki/Photophosphorylation |
Photopigments are unstable pigments that undergo a chemical change when they absorb light. The term is generally applied to the non-protein chromophore moiety of photosensitive chromoproteins , such as the pigments involved in photosynthesis and photoreception . In medical terminology, "photopigment" commonly refers to... | https://en.wikipedia.org/wiki/Photopigment |
A photoplethysmogram ( PPG ) is an optically obtained plethysmogram that can be used to detect blood volume changes in the microvascular bed of tissue. [ 1 ] [ 2 ] A PPG is often obtained by using a pulse oximeter which illuminates the skin and measures changes in light absorption. [ 3 ] A conventional pulse oximeter m... | https://en.wikipedia.org/wiki/Photoplethysmograph |
A photopolymer or light-activated resin is a polymer that changes its properties when exposed to light, often in the ultraviolet or visible region of the electromagnetic spectrum . [ 1 ] These changes are often manifested structurally, for example hardening of the material occurs as a result of cross-linking when expos... | https://en.wikipedia.org/wiki/Photopolymer |
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