All articles starting with P
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Phongsawadan of Luang Prabang
The Phongsawadan of Luang Prabang (ພົງສາວະດານຫຼວງພະບາງ) is a Lao palm-leaf chronicle of the kingdom, which Maha Sila Viravong used as the main basis for his 1957 Phongsawadan Lao.
Phonics
Phonics is a method of teaching reading that stresses acquiring letter-sound correspondences and using them in reading and spelling, delivered through systematic or incidental instruction, with approaches including synthetic phonics.
Phonk
Phonk: hip hop subgenre rooted in 1990s Memphis rap, named by SpaceGhostPurrp in the early 2010s; built on cowbell riffs, distorted 808s, and chopped vocals; drift phonk from Russia went viral on TikTok around 2020.
Phonocardiogram
Phonocardiogram (PCG), phonocardiography: graphic recording of heart sounds and murmurs, first attempted by Donders in 1856, developed by Einthoven and Geluc in 1894; noninvasive cardiac screening and AI-based heart sound analysis.
Phonocardiography
Phonocardiography (PCG) is a biomedical technique that records the heart's acoustic vibrations as a waveform, first performed by Einthoven and Geluc in 1894 and later flown on Gemini missions.
Phonograph
The phonograph, also known as the record player or gramophone, is a machine that records sound as a groove and plays it back, patented by Thomas Edison in 1878.
Phonograph and gramophone museums
Phonograph and gramophone museums are institutions whose core holdings are mechanical sound-reproduction machines and playable records, ranging from the Kanazawa Phonograph Museum to private collections in Kerala and China.
Phonograph cylinder
The phonograph cylinder, or wax cylinder, is a cylindrical sound recording medium engraved with a helical groove, the first commercial recorded-sound format, dominant until discs displaced it by about 1910.
Phonograph horn
The phonograph horn is the flared conduit that carried sound from a phonograph's diaphragm to the listener, serving as the machine's only amplification before electrical amplification.
Phonograph record
A phonograph record, also called a vinyl record or gramophone disc, is an analog sound medium storing audio as a spiral groove on a rotating disc.
Phonograph-era recording industry trade associations
The phonograph-era recording industry trade associations were collective bodies of talking machine manufacturers, jobbers, and dealers, active from about 1890 into the 1920s to fight price cutting and set standards.
Phonological rule
Phonological rule: formal operation substituting sounds in a derivation, central to Chomsky and Halle's generative phonology; discussed against Optimality Theory, rule ordering, opacity, and clinical use.
Phonology
Phonology: the linguistic study of sound patterns in spoken language, covering contrastive sound inventories, distributional regularities, and alternations. Key concepts include phonemes, 25–35 distinctive features, and prosodic hierarchy; distinct from phonetics.
Phonon
A phonon is a quantum of vibrational energy in a crystal lattice, a quasiparticle that is the main vehicle through which solids store and conduct heat.
Phonon bottleneck
A phonon bottleneck is a slowdown of hot-carrier relaxation in semiconductors, caused when energy gaps fail to match available phonon energies, relevant to hot-carrier solar cells.
Phonon density of states
The phonon density of states, also called the vibrational density of states, counts the vibrational modes of a crystal per frequency interval and determines heat capacity, entropy, and free energy.
Phonon drag
Phonon drag is a solid-state transport effect in which phonons carrying heat transfer momentum to charge carriers, adding an extra contribution to the thermoelectric power, described theoretically by Conyers Herring in 1954.
Phonon engineering
Phonon engineering is the deliberate design of a material's structure, composition, or interfaces to control phonons, the quasiparticles of crystal-lattice vibration that carry heat, enabling thermoelectrics and device cooling.
Phonon hydrodynamics
Phonon hydrodynamics is a regime of heat transport in crystals in which phonons move collectively like a fluid, producing second sound, Poiseuille flow, and thermal vortices instead of ordinary diffusion.
Phonon magnetic moment
The phonon magnetic moment is a magnetic moment carried by a circularly polarized crystal vibration, or chiral phonon, detectable as Zeeman splitting in a magnetic field.
Phonon mean free path
The phonon mean free path (MFP) is the average distance a phonon, the quantum of lattice vibration, travels between scattering events, spanning nanometers to millimeters within one material.
Phonon polariton
A phonon polariton is a quasiparticle formed by strong coupling between infrared photons and polar optical phonons in crystals like silicon carbide and boron nitride, first predicted in 1951.
Phonon polariton canalization
Canalization of hyperbolic phonon polaritons is a propagation regime in which polaritons in anisotropic crystals travel as highly collimated, diffraction-free beams with a nearly fixed group velocity direction.
Phonon thermal Hall effect
The phonon thermal Hall effect is a magnetic-field-induced transverse heat current carried by phonons, first observed in 2005 in terbium gallium garnet; its mechanism remains debated.
Phonon-glass electron-crystal
Phonon-glass electron-crystal (PGEC) is a design concept for thermoelectric materials, introduced by Glen A. Slack in 1995, calling for solids that conduct heat poorly but electricity well.
Phonon-liquid electron-crystal in copper selenide
The phonon-liquid electron-crystal (PLEC) concept describes copper selenide, where a rigid selenium sublattice conducts charge while liquid-like copper ions suppress heat transport, proposed in 2012.
PhononDB
PhononDB is an open database of first-principles phonon calculations covering roughly 10,000 inorganic crystals, created by Atsushi Togo and Isao Tanaka at Kyoto University using VASP and phonopy.
Phononic crystal
A phononic crystal is an artificial, periodically structured material that controls sound and elastic waves through acoustic band gaps, a concept developed since the 1990s by analogy to photonic crystals.
Phononic metamaterial
A phononic metamaterial is an engineered composite material that controls mechanical waves through its structure rather than its composition, creating bandgaps where waves cannot travel, and enabling vibration isolation, acoustic filtering, and seismic shielding.
Phonophobia
Phonophobia, fear of sound, is an anticipatory fear of and avoidance of sound in audiology, and migraine-related sound intolerance in neurology; distinct from hyperacusis and misophonia, treated with desensitization and counseling.