| dynamic refraction | Refraction of the eye during accommodation. (05 Mar 2000) |
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| angle of refraction | <optics> The angle that a ray leaving a refracting medium makes with a line drawn perpendicular to the surface of this medium. (05 Mar 2000) |
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| refraction | <physics> Bending of waves as they pass from a medium having one refractive index to a medium (or region within a medium) having a different refractive index. (09 Oct 1997) |
| refraction, angle of | <microscopy> The acute angle between the normal to a refracting surface at the point of incidence, and the refracted ray. (05 Aug 1998) |
| refraction, ocular | Refraction of light effected by the media of the eye. It also includes the determination of the refractive state and refractive correction. (12 Dec 1998) |
| static refraction | Refraction without accommodation. (05 Mar 2000) |
| double refraction | <microscopy> The refraction of light in two slightly different directions to form two rays or vector components. Each ray is polarized, and their vibration directions are perpendicular to each other. Furthermore, each ray has a different velocity, and therefore a different refractive index. See: birefringence. (05 Aug 1998) |
| index of refraction | <physics> For a given wavelength, this is the ratio of the velocity of light in vacuum (c) to the velocity of light in a refractive material (for example, glass, plasma, etc.). (09 Oct 1997) |
| law of refraction | For two given media, the sine of the angle of incidence bears a constant relation to the sine of the angle of refraction. Synonym: Descartes' law, Snell's law. (05 Mar 2000) |
| specific dynamic action | The increase of heat production caused by the ingestion of food, especially of protein. (05 Mar 2000) |
| dynamic aorta | Abnormally marked pulsations of aorta. (05 Mar 2000) |
| dynamic compliance of lung | The value obtained when lung compliance is estimated during breathing by dividing the tidal volume by the difference in instantaneous transpulmonary pressures at the ends of the respiratory excursions, when flow in the airway is momentarily zero; this value deviates markedly from static compliance in patients in whom resistances and compliances are not uniform throughout the lung (i.e., uneven time constants). (05 Mar 2000) |
| dynamic computed tomography | Computed tomography with rapid injection of contrast medium, usually with sequential scans at only one or a few levels; used to enhance the vascular compartment. Synonym: dynamic CT. (05 Mar 2000) |
| dynamic CT | Computed tomography with rapid injection of contrast medium, usually with sequential scans at only one or a few levels; used to enhance the vascular compartment. Synonym: dynamic CT. (05 Mar 2000) |
| dynamic demography | A study of the functioning of a community, including statistical records. (05 Mar 2000) |
| dynamic disease | A physical disorder with no known or detectable organic basis to explain the symptoms. See: behaviour disorder, neurosis. Synonym: dynamic disease, functional disease, functional illness. (05 Mar 2000) |