/di frak"sheuhn/, n. Physics.1. the phenomenon exhibited by wave fronts that, passing the edge of an opaque body, are modulated, thereby causing a redistribution of energy within the front: it is detectable in light waves by the presence of a pattern of closely spaced dark and light bands (diffraction pattern) at the edge of a shadow.2. the bending of waves, esp. sound and light waves, around obstacles in their path.[1665-75; < NL diffraction- (s. of diffractio) a breaking up, equiv. to L diffract(us) broken up (ptp. of diffringere) + -ion- -ION. See DIF-, FRACTION]
* * *Spreading of waves around obstacles.It occurs with water waves, sound, electromagnetic waves (see electromagnetic radiation), and small moving particles such as atoms, neutrons, and electrons, which show wavelike properties. When a beam of light falls on the edge of an object, it is bent slightly by the contact and causes a blur at the edge of the shadow of the object. Waves of long wavelength are diffracted more than those of short wavelength.
* * *▪ physicsthe spreading of waves around obstacles. Diffraction takes place with sound; with electromagnetic radiation, such as light, X-rays, and gamma rays; and with very small moving particles such as atoms, neutrons, and electrons, which show wavelike properties. One consequence of diffraction is that sharp shadows are not produced. The phenomenon is the result of interference (i.e., when waves are superimposed, they may reinforce or cancel each other out) and is most pronounced when the wavelength of the radiation is comparable to the linear dimensions of the obstacle. When sound of various wavelengths or frequencies is emitted from a loudspeaker, the loudspeaker itself acts as an obstacle and casts a shadow to its rear so that only the longer bass notes are diffracted there. When a beam of light falls on the edge of an object, it will not continue in a straight line but will be slightly bent by the contact, causing a blur at the edge of the shadow of the object; the amount of bending will be proportional to the wavelength. When a stream of fast particles impinges on the atoms of a crystal, their paths are bent into a regular pattern, which can be recorded by directing the diffracted beam onto a photographic film.
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См. также в других словарях:
Diffraction — La diffraction est le comportement des ondes lorsqu elles rencontrent un obstacle qui ne leur est pas complètement transparent ; le phénomène peut être interprété par la diffusion d une onde par les points de l objet. La diffraction se… … Wikipédia en Français
diffraction — [ difraksjɔ̃ ] n. f. • 1666; du lat. diffractus, p. p. de diffringere « mettre en morceaux » ♦ Phys. Phénomène optique de déviation des rayons lumineux, au voisinage de corps opaques. ⇒ déflexion, dispersion. Par ext. Phénomène analogue pour d… … Encyclopédie Universelle
Diffraction — Dif*frac tion, n. [Cf. F. diffraction.] (Opt.) The deflection and decomposition of light in passing by the edges of opaque bodies or through narrow slits, causing the appearance of parallel bands or fringes of prismatic colors, as by the action… … The Collaborative International Dictionary of English
diffraction — 1670s, from Fr. diffraction (17c.) or directly from Mod.L. diffractionem (nom. diffractio), noun of action from pp. stem of L. diffringere break in pieces, from dis apart (see DIS (Cf. dis )) + frangere to break (see FRACTION (Cf. fraction)) … Etymology dictionary
Diffraction — des Lichts, s. Beugung des Lichts … Herders Conversations-Lexikon
diffraction — DIFFRACTION. sub. fém. Terme d Optique. Inflexion ou détour que subissent les rayons de lumière en rasant la surface d un corps … Dictionnaire de l'Académie Française 1798
diffraction — ► NOUN Physics ▪ the process by which a beam of light or other system of waves is spread out as a result of passing through a narrow aperture or across an edge. DERIVATIVES diffract verb diffractive adjective. ORIGIN Latin, from diffringere break … English terms dictionary
diffraction — [di frak′shən] n. [ML diffractio < L diffractus: see DIFFRACT] 1. the breaking up of a ray of light into dark and light bands or into the colors of the spectrum, caused by the interference of one part of a beam with another, as when the ray is … English World dictionary
Diffraction — Computer generated intensity pattern formed on a screen by diffraction from a square aperture … Wikipedia
Diffraction X — Diffractométrie de rayons X La diffractométrie de rayons X (DRX, on utilise aussi souvent l abréviation anglaise XRD pour X ray diffraction) est une technique d analyse basée sur la diffraction des rayons X sur la matière. La diffraction n ayant… … Wikipédia en Français