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Index Of Wave Articles
This is a list of Wave topics. 0–9 *21 cm line A *Abbe prism *Absorption spectroscopy *Absorption spectrum *Absorption wavemeter *Acoustic wave *Acoustic wave equation *Acoustics *Acousto-optic effect *Acousto-optic modulator *Acousto-optics *Airy disc *Airy wave theory *Alfvén wave *Alpha waves *Amphidromic point *Amplitude *Amplitude modulation *Animal echolocation *Antarctic Circumpolar Wave * Antiphase *Aquamarine Power *Arrayed waveguide grating *Artificial wave *Atmospheric diffraction *Atmospheric wave *Atmospheric waveguide *Atom laser *Atomic clock *Atomic mirror *Audience wave *Autowave *Averaged Lagrangian B *Babinet's principle *Backward wave oscillator *Bandwidth-limited pulse *beat *Berry phase *Bessel beam *Beta wave *Black hole *Blazar *Bloch's theorem *Blueshift *Boussinesq approximation (water waves) *Bow wave *Bragg diffraction *Bragg's law *Breaking wave *Bremsstrahlung, Electromagnetic radiation *Brillouin scattering *Bullet bow shockwave *Burgers' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wave
In physics, mathematics, and related fields, a wave is a propagating dynamic disturbance (change from equilibrium) of one or more quantities. Waves can be periodic, in which case those quantities oscillate repeatedly about an equilibrium (resting) value at some frequency. When the entire waveform moves in one direction, it is said to be a ''traveling wave''; by contrast, a pair of superimposed periodic waves traveling in opposite directions makes a '' standing wave''. In a standing wave, the amplitude of vibration has nulls at some positions where the wave amplitude appears smaller or even zero. Waves are often described by a '' wave equation'' (standing wave field of two opposite waves) or a one-way wave equation for single wave propagation in a defined direction. Two types of waves are most commonly studied in classical physics. In a '' mechanical wave'', stress and strain fields oscillate about a mechanical equilibrium. A mechanical wave is a local deformation (str ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Amplitude
The amplitude of a periodic variable is a measure of its change in a single period (such as time or spatial period). The amplitude of a non-periodic signal is its magnitude compared with a reference value. There are various definitions of amplitude (see below), which are all functions of the magnitude of the differences between the variable's extreme values. In older texts, the phase of a periodic function is sometimes called the amplitude. Definitions Peak amplitude & semi-amplitude For symmetric periodic waves, like sine wave A sine wave, sinusoidal wave, or just sinusoid is a curve, mathematical curve defined in terms of the ''sine'' trigonometric function, of which it is the graph of a function, graph. It is a type of continuous wave and also a Smoothness, smooth p ...s, square waves or triangle waves ''peak amplitude'' and ''semi amplitude'' are the same. Peak amplitude In audio system measurements, telecommunications and others where the wikt:measurand, measu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Mirror
In physics, an atomic mirror is a device which reflects neutral atoms in the similar way as a conventional mirror reflects visible light. Atomic mirrors can be made of electric fields or magnetic fields, electromagnetic waves or just silicon wafer; in the last case, atoms are reflected by the attracting tails of the van der Waals attraction (see quantum reflection). Such reflection is efficient when the normal component of the wavenumber of the atoms is small or comparable to the effective depth of the attraction potential (roughly, the distance at which the potential becomes comparable to the kinetic energy of the atom). To reduce the normal component, most atomic mirrors are blazed at the grazing incidence. At grazing incidence, the efficiency of the quantum reflection can be enhanced by a surface covered with ridges ( ridged mirror). The set of narrow ridges reduces the van der Waals attraction of atoms to the surfaces and enhances the reflection. Each ridge blocks ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atomic Clock
An atomic clock is a clock that measures time by monitoring the resonant frequency of atoms. It is based on atoms having different energy levels. Electron states in an atom are associated with different energy levels, and in transitions between such states they interact with a very specific frequency of electromagnetic radiation. This phenomenon serves as the basis for the International System of Units' (SI) definition of a second:The second, symbol s, is the SI unit of time. It is defined by taking the fixed numerical value of the caesium frequency, \Delta \nu_\mathsf, the unperturbed ground-state hyperfine transition frequency of the caesium 133 atom, to be when expressed in the unit Hz, which is equal to s−1. This definition is the basis for the system of International Atomic Time (TAI), which is maintained by an ensemble of atomic clocks around the world. The system of Coordinated Universal Time (UTC) that is the basis of civil time implements leap seconds to allo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atom Laser
An atom laser is a coherent state of propagating atoms. They are created out of a Bose–Einstein condensate of atoms that are output coupled using various techniques. Much like an optical laser, an atom laser is a coherent beam that behaves like a wave. There has been some argument that the term "atom laser" is misleading. Indeed, "laser" stands for "Light Amplification by Stimulated Emission of Radiation" which is not particularly related to the physical object called an atom laser, and perhaps describes more accurately the Bose–Einstein condensate (BEC). The terminology most widely used in the community today is to distinguish between the BEC, typically obtained by evaporation in a conservative trap, from the atom laser itself, which is a propagating atomic wave obtained by extraction from a previously realized BEC. Some ongoing experimental research tries to obtain directly an atom laser from a "hot" beam of atoms without making a trapped BEC first. Introduction The first pul ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Waveguide
{{Unreferenced, date=December 2008 An atmospheric waveguide is an atmospheric flow feature that improves the propagation of certain atmospheric waves. The effect arises because wave parameters such as group velocity or vertical wavenumber depend on mean flow direction and strength. Thus, for instance, westerlies might be a good waveguide for eastward-traveling waves, but might strongly dissipate westward-traveling waves, by increasing or decreasing their vertical wavenumber, respectively. Modification of the waves' group velocity will change their meridional propagation speed, directing them more polewards or more equator The equator is a circle of latitude, about in circumference, that divides Earth into the Northern and Southern hemispheres. It is an imaginary line located at 0 degrees latitude, halfway between the North and South poles. The term can als ...wards. Atmosphere ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Wave
An atmospheric wave is a periodic disturbance in the fields of atmospheric variables (like surface pressure or geopotential height, temperature, or wind velocity) which may either propagate (''traveling wave'') or not (''standing wave''). Atmospheric waves range in spatial and temporal scale from large-scale planetary waves (Rossby waves) to minute sound waves. Atmospheric waves with periods which are harmonics of 1 solar day (e.g. 24 hours, 12 hours, 8 hours... etc.) are known as atmospheric tides. Causes and effects The mechanism for the forcing of the wave, for example, the generation of the initial or prolonged disturbance in the atmospheric variables, can vary. Generally, waves are either excited by heating or dynamic effects, for example the obstruction of the flow by mountain ranges like the Rocky Mountains in the U.S. or the Alps in Europe. Heating effects can be small-scale (like the generation of gravity waves by convection) or large-scale (the formation of Rossby w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Atmospheric Diffraction
Atmospheric diffraction is manifested in the following principal ways: * Optical atmospheric diffraction * Radio wave diffraction is the scattering of radio frequency or lower frequencies from the Earth's ionosphere, resulting in the ability to achieve greater distance radio broadcasting. * Sound wave diffraction is the bending of sound waves, as the sound travels around edges of geometric objects. This produces the effect of being able to hear even when the source is blocked by a solid object. The sound waves bend appreciably around the solid object. However, if the object has a diameter greater than the acoustics, acoustic wavelength, a 'sound shadow' is cast behind the object where the sound is inaudible. (Note: some sound may be propagated through the object depending on material). Optical atmospheric diffraction When light travels through thin clouds made up of nearly uniform sized water or aerosol droplets or ice crystals, diffraction or bending of light occurs as the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Artificial Wave
Artificial waves are human-made Ocean surface waves, waves usually created on a specially designed surface or in a Swimming pool, pool. Making waves {{Further, Mechanical wave Surface waves can be created by any moving object displacing fluid: turbine blades, paddles, a hand, a flung stone, etc. Each pulse of water (or Crest (physics), crest) pushed outward from the disturbance leaves a space (or trough) behind it which causes another, smaller pulse to follow: thus a thrown stone's single impact causes a series of ripples. Larger waves can be built up if a series of movements are timed to reinforce waves' motion, much like a person sliding back and forth in a bathtub. Boundaries and obstacles also shape waves by concentrating or dissipating some of the wave's energy. When fluid flows over a surface which diverts it upward, this flow can rise above the rest of the fluid in a standing wave which remains in one place while the flow lasts. An example of a natural standing wave may b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arrayed Waveguide Grating
{{Unreferenced, date=April 2019 Arrayed waveguide gratings (AWG) are commonly used as optical (de)multiplexers in wavelength division multiplexed (WDM) systems. These devices are capable of multiplexing many wavelengths into a single optical fiber, thereby increasing the transmission capacity of optical networks considerably. The devices are based on a fundamental principle of optics that light waves of different wavelengths do not interfere linearly with each other. This means that, if each channel in an optical communication network makes use of light of a slightly different wavelength, then the light from many of these channels can be carried by a single optical fiber with negligible crosstalk between the channels. The AWGs are used to multiplex channels of several wavelengths onto a single optical fiber at the transmission end and are also used as demultiplexers to retrieve individual channels of different wavelengths at the receiving end of an optical communication ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aquamarine Power
Aquamarine Power was a wave energy company, founded in 2005 to commercialise the Oyster wave energy converter, a device to capture energy from near-shore waves. The company's head offices were in Edinburgh, Scotland. The company ceased to trade on 20 November 2015. History The Oyster concept originated from studies conducted in 2003 by the wave power research team at Queen's University, Belfast, led by Professor Trevor Whittaker. The studies were co-funded by the Engineering and Physical Sciences Research Council and Allan Thomson, who had previously founded and led the UK's first commercial wave energy company, Wavegen. In 2005, Thomson founded Aquamarine Power to progress the commercialisation of the Oyster device. In 2007 Scottish & Southern Energy subsidiary Renewable Technology Ventures Limited invested in Aquamarine with a further investment in 2010. In February 2009, Aquamarine Power and Queen's University signed an agreement to extend their R&D partnership to 2014. In ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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