| neutral axis of straight beam | The axis perpendicular to the plane of loading of a beam at stresses within the proportional limit; it lies at the gravity axis of the cross-section of the beam. (05 Mar 2000) |
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| neutral beam injection | <radiobiology> This is one of the fundamental plasma heating methods. A particle accelerator is used to create fast ion beams (the particle energies are on the order of 100 keV), the ion beam is then passed through a neutral gas region, where the ions neutralise via charge-exchange reactions with the neutral gas. The neutralised beam is then injected into a magnetically confined plasma. The neutral atoms are unaffected (not confined) by the magnetic field, but ionize as they penetrate into the plasma. The high-energy ions then transfer some of their energy to the plasma particles in repeated collisions, and heat the plasma. (09 Oct 1997) |
| electron beam | <microscopy> A stream of electrons in an electron optical system. (05 Aug 1998) |
| palatine surface of horizontal plate of palatine bone | The inferior surface of the horizontal plate of the palatine bone. Synonym: facies palatina laminae horizontalis ossis palatini. (05 Mar 2000) |
| medial crus of the horizontal part of the facial canal | Medially-placed, anteriorly-directed first portion of the horizontal part of the facial canal. See: horizontal part of facial canal. Synonym: medial crus of the horizontal part of the facial canal. (05 Mar 2000) |
| great horizontal fissure | Horizontal fissure that divides the ansiform lobule into its major parts, crus I (superior semilunar lobule) and crus II (inferior semilunar lobule). Synonym: fissura horizontalis cerebelli, great horizontal fissure. (05 Mar 2000) |
| horizontal | 1. Pertaining to, or near, the horizon. "Horizontal misty air." 2. Parallel to the horizon; on a level; as, a horizontalline or surface. 3. Measured or contained in a plane of the horizon; as, horizontal distance. Horizontal drill, a drilling machine having a horizontal drill spindle. Horizontal engine, one the piston of which works horizontally. Horizontal fire, the fire of ordnance and small arms at point-blank range or at low angles of elevation. <physics> Horizontal force, the distance in a horizontal plane to which a gun will throw a projectile. Horizontal water wheel, a water wheel in which the axis is vertical, the buckets or floats revolving in a horizontal plane, as in most turbines. Origin: Cf. F. Horizontal. Source: Websters Dictionary (01 Mar 1998) |
| horizontal atrophy | A progressive loss of alveolar and supporting bone surrounding the teeth, beginning at the most coronal level of the bone. Synonym: horizontal resorption. (05 Mar 2000) |
| horizontal cell | A type of nonspiking interneuron found in the retina, named for its morphology. Horizontal cells process the information from a large number of photoreceptors and synapse onto ganglion cells and other cell types in the retina. (18 Nov 1997) |
| horizontal cell of Cajal | A small fusiform cell found in the superficial layer of the cerebral cortex with its long axis placed horizontally. Synonym: Cajal's cell. (05 Mar 2000) |
| horizontal cells of retina | Cell's in the outer part of the inner nuclear layer of the retina that lie with their axes more or less parallel with the surface. They are thought to connect the rods of one part of the retina with cones of another part. (05 Mar 2000) |
| horizontal classification | <zoology> Classification which stresses grouping together taxa in a similar stage of evolution, rather than location on the same phyletic line. See: Vertical classification. (09 Jan 1998) |
| horizontal fissure of cerebellum | Horizontal fissure that divides the ansiform lobule into its major parts, crus I (superior semilunar lobule) and crus II (inferior semilunar lobule). Synonym: fissura horizontalis cerebelli, great horizontal fissure. (05 Mar 2000) |
| horizontal fissure of right lung | The deep fissure that separates the upper and middle lobes of the right lung. Synonym: fissura horizontalis pulmonis dextri, horizontal fissure of right lung, minor fissure. (05 Mar 2000) |
| horizontal fracture | A fracture of the facial bones in which there is a horizontal fracture at the base of the maxillae above the apices of the teeth. Synonym: horizontal fracture, Le Fort I fracture. (05 Mar 2000) |