| ion cyclotron emission | <radiobiology> As ions gyrate around in a magnetic field (see also larmor radius or cyclotron radius), they radiate radio-frequency electromagnetic waves. This is known as ion cyclotron emission, and can be measured to help diagnose a plasma. (09 Oct 1997) |
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| electron cyclotron emission | <physics, radiobiology> As electrons gyrate around in a magnetic field (see also larmor radius or cyclotron radius), they radiate radio-frequency electromagnetic waves. This is known as electron cyclotron emission, and can be measured to help diagnose a plasma. (09 Oct 1997) |
| emission | 1. The act of sending or throwing out; the act of sending forth or putting into circulation; issue; as, the emission of light from the sun; the emission of heat from a fire; the emission of bank notes. 2. That which is sent out, issued, or put in circulation at one time; issue; as, the emission was mostly blood. 3. <physics> Emission theory, the theory of Newton, regarding light as consisting of emitted particles or corpuscles. See Corpuscular theory. Origin: L. Emissio: cf. F. Emission. Source: Websters Dictionary (01 Mar 1998) |
| emission-computed tomography | <radiology> Tomography using emissions from radionuclides and a computer algorithm to reconstruct the image. (20 Jun 2000) |
| emission electron | <physics>? A beta particle resulting from radioactive decay. (05 Mar 2000) |
| emission offset | <chest medicine> A reduction in the air pollution emissions of existing sources to compensate for emissions from new sources. (05 Dec 1998) |
| emission standard | This regulatory value is a quantitative limit on the emission or discharge of a potentially toxic substance from a source. The simplest form for regulatory purposes is a uniform emission standard (UES) where the same limit is placed on all emissions of a particular contaminant. (09 Oct 1997) |
| flame emission spectrophotometry | Determination of the concentration of an element by measurement of light emitted when the element is excited by energy in the form of heat. (05 Mar 2000) |
| binocular microscope | <instrument, microscopy> A microscope fitted with double eyepieces for vision with both eyes. The purpose in dividing the same image from a single objective of the usual compound micro-scope is to reduce eyestrain and muscular fatigue which may result from monocular, high-power microscopy. The purpose in obtaining a different image for each of two oculars is to provide stereoscopy by means of two different angles of view. There are two kinds of stereoscopic microscopes: binobjective (Greenough) older type and monobjective (common main objective) newer type. (See stereo microscope, Greenough microscope, etc.) (05 Aug 1998) |
| Rheinberg microscope | <instrument> A modified form of dark-field microscope in which the central opaque stop in the condenser is replaced by a coloured filter, producing a background of contrasting colour against which the specimen is illuminated. (05 Mar 2000) |
| Greenough microscope | <instrument, microscopy> One of two kinds of stereomicroscopes with two separate compound microscopes, one for each eye, focused on the same object. The other kind has a common main objective. See: binocular microscope. (05 Aug 1998) |
| phase-contrast microscope | <instrument> A specially constructed microscope that has a special condenser and objective containing a phase-shifting ring whereby small differences in index of refraction are made visible as intensity or contrast differences in the image; particularly useful for examining structural details in transparent specimens such as living or unstained cells and tissues. (05 Mar 2000) |
| microscope | <instrument> A piece of laboratory equipment that is used to magnify small things that are too small to be seen by the naked eye, or too small for the details to be seen by the naked eye, so that their finer details can be seen and studied. Examples are the light (or optical) microscope, electron microscope, X-ray microscope, and acoustic microscope. (09 Oct 1997) |
| microscope, compound | A microscope that consists of two microscopes in series, the first serving as the ocular lens (close to the eye) and the second serving as the objective lens (close to the object to be viewed). Credit for creating the compound microscope goes usually to the dutch spectaclemakers hans and zacharias janssen who in 1590 invented an instrument that could be used as either a microscope or telescope. The compound microscope evolved into the dominant type of optical microscope today. (12 Dec 1998) |
| microscope, electron | <microscopy> An electron-optical device which produces a magnified image of an object. Detail may be revealed by virtue of selective transmission, reflection, or emission of electrons by the object. (05 Aug 1998) |