| NIL | noise interference level |
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| PSIL | preferred frequency speech interference level |
| RFI | radiofrequency interference; recurrence-free interval; renal failure index |
| RI | radiation intensity; radioactive isotope; radioimmunology; recession index; recombinant inbred [stra... |
| SIL | soluble interleukin; speech interference level |
| differential interference contrast | <technique> A mode of contrast generation in microscopy that yields an image with a shadow relief. The relief reflects the gradient of optical path difference. Differential Interference Contrast, which is a form of interferenc microscopy that uses polarizing beam splitters, can be of the Smith or Nomarski type. Acronym: DIC (05 Aug 1998) |
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| dissociation by interference | The simultaneous operation of two separate cardiac pacemaking foci that are unassociated because of interference (a normal physiologic phenomenon) due to rendering their respective territories refractory to each other. Usually atrioventricular dissociation is indicated, the rates being quite close to each other with the atrial rate slightly faster than that of the pacemaker in control of the ventricles. Capture is in either direction, usually the ventricle by the atrium, in incomplete dissociation. H Synonym: dissociation by interference. (05 Mar 2000) |
| interference | Opposition or hampering of an action or procedure. Origin: L. Ferire = to strike (18 Nov 1997) |
| interference beat | Ventricular capture in forms of A-V dissociation due to interference. (05 Mar 2000) |
| interference diffraction patterns | The patterns arising from the recombination of beams of light or other waves after they have been split and one set of rays have undergone a phase retardation relative to the other. Such patterns formed by simple objects give information on the correctness of the focus and the presence or absence of optical defects. (18 Nov 1997) |
| interference dissociation | The simultaneous operation of two separate cardiac pacemaking foci that are unassociated because of interference (a normal physiologic phenomenon) due to rendering their respective territories refractory to each other. Usually atrioventricular dissociation is indicated, the rates being quite close to each other with the atrial rate slightly faster than that of the pacemaker in control of the ventricles. Capture is in either direction, usually the ventricle by the atrium, in incomplete dissociation. H Synonym: dissociation by interference. (05 Mar 2000) |
| interference figure | <microscopy> The conoscopic pattern of extinction positions of a crystal superimposed on the pattern of interference colours corresponding to the full cone of directions by which the crystal is illuminated, each direction showing its own interference colour. (05 Aug 1998) |
| interference microscope | <instrument> A specially constructed microscope in which the entering light is split into two beams which pass through the specimen and are recombined in the image plane where the interference effects make the transparent (invisible) refractile object details become visible as intensity differences; permits measurements of light retardation, index of refraction, and thickness and mass of specimen; it is useful in the examination of living or unstained cells. (05 Mar 2000) |
| interference microscopy | <procedure> Although all image formation depends on interference, the term is generally restricted to systems in which contrast comes from the recombination of a reference beam with light that has been retarded by passing through the object. Because the phase retardation is a consequence of the difference in refractive index between specimen and medium and because the the refractive increment is almost the same for all biological molecules, it is possible to measure the amount of dry mass per unit area of the specimen by measuring the phase retardation. Quantification of the phase retardation is usually done by using a compensator to reduce the bright object to darkness (see Senarmont and Ehrlinghaus compensators). Two major optical systems have been used the Jamin Lebedeff system and the Mach Zehnder system. These instruments are often referred to as interferometers, since they are designed for measuring phase retardation. Although their use has passed out of fashion, it may be that they will be employed more frequently in future in conjunction with image analysing systems. (18 Nov 1997) |
| interference reflection microscopy | <procedure> An optical technique for detecting the topography of the side of a cell in contact with a planar substrate and for providing information on the separation of the plasmalemma from the substrate. Interference between the reflections from the substrate medium interface and the reflections from the plasmalemma medium interface generate the image. (18 Nov 1997) |