| electrocardiographic wave | <cardiology, physiology> A deflection of special shape and extent in the electrocardiogram representing the electric activity of a portion of the heart muscle. (05 Mar 2000) |
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| electrohydraulic shock wave lithotripsy | Destruction of calculi (urinary tract or other) by fragmentation using shock waves sent transcutaneously. (05 Mar 2000) |
| electromagnetic wave | <physics> A wave of electric and magnetic fields that can move through space. Particles which make up the waves are called photons. (09 Oct 1997) |
| electrostatic wave | <radiobiology> Longitudinal oscillations appearing in a plasma due to a perturbation of electric neutrality. For a cold unmagnetised plasma, or at large wavelengths, the frequency of these waves is by definition the plasma frequency. (09 Oct 1997) |
| transverse wave | <radiobiology> Waves in which the direction of the oscillation is perpendicular (transverse) to the direction of the wave propagation. Examples include plucked strings and electromagnetic waves in free space or air. (09 Oct 1997) |
| T wave | The next deflection in the electrocardiogram following the QRS complex; represents ventricular repolarization. (05 Mar 2000) |
| excitation wave | A wave of altered electrical conditions that is propagated along a muscle fibre preparatory to its contraction. (05 Mar 2000) |
| extracorporeal shock wave lithotripsy | <procedure> This procedure uses sound waves delivered inside a water bath to pulverise kidney stones painlessly inside the body. (11 Nov 1997) |
| y wave | The wave in the atrial and venous pulse curves reflecting rapid filling of the ventricles just after the atrioventricular valves open. (05 Mar 2000) |
| U wave | A positive wave following the T wave of the electrocardiogram. (05 Mar 2000) |
| fluid wave | A sign of free fluid in the abdominal cavity; percussion on one side of the abdomen transmits a wave that is felt on the opposite side. (05 Mar 2000) |
| free wave | <radiobiology> A wave (for example, electromagnetic) traveling in a homogeneous infinite medium (no boundary conditions). (09 Oct 1997) |
| longitudinal wave | <physics> Waves where the variation of the field is partially or totally in the direction of propagation (parallel to wavennumber, k [a vector]). Examples include sound waves and Langmuir waves. Contrasted with transverse waves, where the variation is perpendicular to the direction of propagation, such as light waves. (13 Nov 1997) |
| aperture for electron microscopy | <technique> Anode aperture: The opening in the accelerating voltage anode shield of the electron gun through which the electrons must pass to irradiate the specimen. Condenser aperture: An opening in the condenser lens controlling the number of electrons entering the lens and the angular aperture of the electron beam. The angular aperture can also be controlled by the condenser lens current. Physical objective aperture: A metallic diaphragm, with a small central hole, used to limit the cone of electrons accepted by the objective lens. This improves image-contrast since highly scattered electrons are prevented from arriving at the Gaussian image plane and therefore cannot contribute to background fog. Aplanatic. Free from spherical aberration and coma. (05 Aug 1998) |
| Auger electron | An electron ejected from a lower energy orbital after a photoelectric interaction of an X-ray photon with a K-shell electron by the characteristic radiation photon; the Auger electron recoils with energy equal to the characteristic radiation less the difference in shell binding energies. See: photoelectric effect. (05 Mar 2000) |