| ATEM | analytic transmission electron microscopy |
|---|---|
| BEI | back-scattered electron imaging; biological exposure indexes; butanol-extractable iodine |
| BeV, Bev | billion electron volts |
| CEM | computerized electroencephalographic map; conventional transmission electron microscope |
| CIDEP | chemically induced dynamic electron polarization |
| orbital sulci | A number of irregularly disposed, variable sulci dividing the inferior or orbital surface of each frontal lobe of the cerebrum into the orbital gyri. Synonym: sulci orbitales. (05 Mar 2000) |
|---|---|
| orbital surface | The surface of a bone which contributes to the walls of the orbit. The NA recognises an orbital surface on the following bones: greater wing of the sphenoid bone; the maxilla; the frontal bone; the zygomatic bone. Synonym: facies orbitalis. (05 Mar 2000) |
| orbital syndrome | <syndrome> An obsolete term referring to neoplastic tissue formation involving the apex of the orbit, causing ophthalmoplegia and optic nerve atrophy. (05 Mar 2000) |
| orbital tubercle of zygomatic bone | A small elevation on the orbital surface of the zygomatic bone, just within the orbital margin, about 1 cm below the zygomaticofrontal suture; it gives attachment to the lateral check ligament, the lateral palpebral ligament, and the suspensory ligament of the eyeball. Synonym: eminentia orbitalis ossis zygomatici, orbital eminence of zygomatic bone, Whitnall's tubercle. (05 Mar 2000) |
| orbital width | The distance between the dacryon and the farthest point on the anterior edge of the outer border of the orbit (Broca), or between the latter point and the junction of the frontolacrimal suture and the posterior edge of the lacrimal groove. (05 Mar 2000) |
| tarso-orbital | Relating to the eyelids and the orbit. (05 Mar 2000) |
| zygomatico-orbital | Relating to the zygomatic bone and the orbit. (05 Mar 2000) |
| zygomatico-orbital artery | <anatomy, artery> Origin, superficial temporal, sometimes middle temporal; distribution, orbicularis oculi muscle and portions of the orbit; anastomoses, lacrimal and palpebral branches of ophthalmic. Synonym: arteria zygomatico-orbitalis. (05 Mar 2000) |
| zygomatico-orbital foramen | The common opening on the orbital surface of the zygomatic bone of the canals transmitting the zygomaticofacial and zygomaticotemporal nerves; sometimes each of these canals has a separate opening on the orbital surface. Synonym: foramen zygomatico-orbitale. (05 Mar 2000) |
| fronto-orbital area | The cerebral cortex covering the basal surface of the frontal lobes. Synonym: fronto-orbital area. (05 Mar 2000) |
| 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) |
| backscattered electron | <microscopy> Produced by an incident electron colliding with the nucleus of an atom in the specimen. The incident electron is then scattered backward about 180 degrees with no appreciable loss of energy, an elastic collision. (05 Aug 1998) |
| backscattered electron imaging | <microscopy> The production of backscattered electrons from a sample varies directly with the specimen's average atomic number, higher atomic number elements produce more backscattered electrons than lower atomic number ones. Detection of Backscattered Electrons is achieved by using a donut shaped solid state saemiconductor device mounted on the bottom of the objective lens. When Backscattered Electrons strike the detector electron-hole pairs are created which are then counted. This quantity is translated into a pixel intensity and displayed on the CRT, forming the image. By splitting the detector into halves (or quadrants) differences in the signal level on the individual detector segments provide surface topography information. (05 Aug 1998) |
| valence electron | One of the electron's that take part in chemical reactions of an atom. (05 Mar 2000) |