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Phosphor bronze
Phosphor bronze is a copper-tin alloy containing a trace of residual phosphorus, prized for strength, corrosion resistance, and fatigue behavior in springs, contacts, and bearings.
Phosphoric acid fuel cell
A phosphoric acid fuel cell (PAFC) uses concentrated phosphoric acid as its electrolyte and runs at 150 to 200 °C; it was the first fuel cell type commercialized.
Phosphorus anode
A phosphorus anode is a battery negative electrode of red or black phosphorus that stores lithium or sodium ions by alloying, offering 2,596 mAh g⁻¹ theoretical capacity.
Photo booth
A photo booth is a self-service machine with a camera that produces a strip of portraits within minutes, first commercialized as Anatol Josepho's Photomaton in 1925.
Photo Booth
Photo Booth is the built-in camera application on Apple's Mac computers, capturing single photos, four-photo 4-up sequences, and video with effects applied live before capture.
Photo print sizes
Photo print sizes, also known as standard photographic print sizes, are standardized dimensions into which photos are printed, chiefly 4×6, 5×7, and 8×10 inches, with larger enlargements above them.
Photo-Fenton oxidation
Photo-Fenton oxidation is an advanced oxidation process for water treatment that combines iron, hydrogen peroxide, and UV or sunlight to generate hydroxyl radicals degrading organic pollutants.
Photoacid generator
A photoacid generator (PAG) is a compound that releases a strong acid when exposed to radiation, the light-sensitive acid source in chemically amplified photoresists used to pattern silicon wafers.
Photoanode
A photoanode is the illuminated electrode of a photoelectrochemical cell where oxidation reactions occur, typically an n-type semiconductor such as TiO2, hematite, or BiVO4, often used for solar water splitting.
Photobiological hydrogen production
Photobiological hydrogen production is the generation of hydrogen gas by photosynthetic microorganisms, chiefly green algae and cyanobacteria, using sunlight to split water, an early-stage technology limited by oxygen sensitivity.
Photocatalytic hydrogen evolution
Photocatalytic hydrogen evolution is the production of hydrogen from water using light-activated semiconductor particles or electrodes, a field begun with Fujishima and Honda's 1972 TiO₂ work.
Photocatalytic overall water splitting by Al-doped SrTiO3
Al-doped SrTiO3 (SrTiO3:Al, also written Al:STO) is a benchmark photocatalyst powder that splits water into hydrogen and oxygen under ultraviolet light without any applied bias.
Photocatalytic plastic upcycling
Photocatalytic plastic upcycling is the use of light-activated catalysts, typically driven by sunlight, to convert plastic waste into value-added chemicals and fuels at ambient temperature and pressure.
Photocatalytic water oxidation
Photocatalytic water oxidation is the light-driven conversion of water to oxygen by a photocatalyst, the oxidative half-reaction of artificial photosynthesis and the rate-determining step of overall water splitting.
Photocatalytic water purification
Photocatalytic water purification is a water treatment method in which light-activated semiconductor catalysts, usually titanium dioxide, degrade organic pollutants and inactivate pathogens, often using sunlight.
Photocathode
A photocathode is a photoemissive surface, usually of alkali metals or semiconductors in a vacuum device, that converts photons into electrons via the photoelectric effect.
Photochemical curing
Photochemical curing is a manufacturing method that uses light, typically ultraviolet, to polymerize liquid resins, adhesives, coatings, and hydrogels into solids, curing most materials fully in 1 to 30 seconds and enabling high-build-rate 3D printing.
Photochemical etching
Photochemical etching, also called photochemical machining or photochemical milling, patterns thin metal sheets by printing a photoresist mask and chemically dissolving exposed areas, producing burr-free, stress-free flat parts used for IC leadframes, screens, and shims.
Photocopier
A photocopier, also called a copy machine or Xerox machine, is an office machine that makes paper copies of documents, most commonly by the dry electrostatic xerography process.
Photoelectrocatalysis
Photoelectrocatalysis (PEC) is a water-treatment method combining photocatalysis with electrochemistry, in which an applied bias separates charge on a semiconductor photoelectrode to degrade organic pollutants.
Photoelectrochemical water splitting
Photoelectrochemical water splitting is a method of producing hydrogen from water using sunlight and semiconductor photoelectrodes in a single device, first demonstrated in 1972 and still uncommercialized.
Photogrammetry
Photogrammetry builds 3D models, point clouds, and orthophotos from overlapping photographs taken from many positions, and is used in surveying, geology, archaeology, and underwater exploration.
Photographic paper
Photographic paper is paper coated with light-sensitive materials, historically silver salts, used to make positive prints from photographic negatives; early printing-out papers needed light alone, later papers chemical development.
Photolithography
Photolithography, also known as optical lithography, is the semiconductor manufacturing process that transfers a geometric circuit pattern from a photomask onto a photoresist coating on a wafer.
Photomask
A photomask, also known as a photoreticle or optical mask, is a transparent quartz plate bearing an integrated circuit layer's pattern, projected by lithography onto silicon wafers.
Photometric stereo
Photometric stereo is a computer vision method that recovers surface normals and albedo from multiple images taken with a fixed camera under different lighting directions.
Photometric visual servoing
Photometric visual servoing (PVS) is a robot control technique that uses the luminance of all pixels as the visual feature, proposed by Christophe Collewet and Eric Marchand in 2011.
Photomodeler
PhotoModeler is close-range photogrammetry software developed by Eos Systems in Vancouver, British Columbia, that extracts measurements and 3D models from ordinary photographs, used in accident reconstruction, forensics, manufacturing, and surveying.
Photon recycling in lead iodide perovskite solar cells
Photon recycling in lead iodide perovskite solar cells is the repeated reabsorption and reemission of photons within the absorber, first demonstrated directly in 2016, enabling long energy-transport distances.
Photon recycling in perovskite solar cells
Photon recycling in perovskite solar cells is the process by which photons from radiative recombination are reabsorbed within the perovskite, extending carrier diffusion length and raising open-circuit voltage.