| STM | scanning tunneling microscope; short-term memory; streptomycin |
|---|---|
| CTT | cefotetan; central tegmental tract; central transmission time; compressed tablet triturate; computer... |
| DT | defibillation threshold; delirium tremens; dental technician; depression of transmission; dietetic [... |
| IVT | index of vertical transmission; interventional video tomography; intrasound vibration test; intraven... |
| NMT | neuromuscular tension; neuromuscular transmission; N-methyltransferase; N-myristoyltransferase; no m... |
| opaque microscope | <instrument> A microscope with a condenser built around the objective; used for the investigation of opaque, or only slightly translucent, minute specimens. Synonym: opaque microscope. (05 Mar 2000) |
|---|---|
| operating microscope | <instrument> A binocular microscope used to obtain good visualization of fine structures in the operating field; in the standing type of microscope, a motorised zoom lens system operated by hand or foot controls provides an adjustable working distance; in headborne models, interchangeable oculars provide the magnification needed. Synonym: operating microscope. (05 Mar 2000) |
| optical microscope | <instrument, microscopy> A very ambiguous term since all microscopes involve optics, better to specify light, acoustic, X-ray or electron microscope, etc. (05 Aug 1998) |
| television microscope | <instrument> A microscope in which the image is observed by a television camera that produces a television display; it is used for quantitative studies, display to a large audience, or examinations in ultraviolet and infrared regions of the spectrum. (05 Mar 2000) |
| ultrasonic microscope | <instrument> A microscope that has lenses designed to use acoustic energy so that the ultrasonic wavelengths may be utilised; by means of transducers, the information is translated to a form that may be visualised or recorded. (05 Mar 2000) |
| ultraviolet microscope | <instrument> A microscope having optics of quartz and fluorite that allow transmission of light waves shorter than those of the visible spectrum, i.e., below 400 nm; the image is made visible by photography, fluorescence of special glasses, or television; in a scanning instrument the receptor is a multiplier phototube. (05 Mar 2000) |
| field-emission microscope | <instrument, microscopy> Either one of two kinds of point-projection microscopes, both invented by E. W. Muller: (1) The older device (1936) is a specialised cathode-ray tube, employing field-emission of electrons from a negatively charged tip of a very sharp needle in a vacuum, by point-projection of the image onto a positively charged, fluorescent screen. (2) A later device (field-ion-mission microscope, 1950) emits absorbed helium ions from an anode. (05 Aug 1998) |
| field ion microscope | <instrument> Type of microscopy in which the specimen is illuminated with ions, often gallium ions, that are focussed electrostatically. The ions remove components of the specimen, lower atomic masses first. These are imaged and provide information on elemental distribution with a resolution of perhaps 30 nm. (18 Nov 1997) |
| fluorescence microscope | <instrument, microscopy> A microscope illuminated by ultraviolet or blue light so that the object may re-radiate light of longer wavelengths. To protect the eyes, a W-absorbing filter should be provided if not built into the fluorescence microscope. (05 Aug 1998) |
| fluorescent microscope | <instrument> A microscope equipped to examine material that fluoresces under ultraviolet (UV) light. (12 Dec 1998) |
| flying spot microscope | <instrument> A microscope in which a moving spot of light is imaged in the object plane, the energy transmitted by the specimen being detected with a photoelectric cell; the light source may be a cathode ray tube, a scanning disk or drum, or an oscillating mirror. (05 Mar 2000) |
| laser microscope | <instrument> A microscope in which a laser beam is focused on a microscopic field, causing it to vaporise; the emitted radiation is analyzed by means of a microspectrophotometer; at a low intensity the laser is employed as the light source in an interference microscope. (05 Mar 2000) |
| light microscope | <instrument> The most common type of microscope (a device used to magnify small objects or substances) used in laboratories. The device works by passing visible light through a condenser and an objective lens. (09 Oct 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) |