| grid | An electric utility's system for distributing power. (05 Dec 1998) |
|---|---|
| grid connection | Joining a plant that generates electric power to a utility system so that electricity can flow in either direction between the utility system and the plant. (05 Dec 1998) |
| grid ratio | In a radiographic scatter-absorbing grid, the ratio of the height to the width of the gaps between lead strips; a higher grid ratio removes more scattered radiation but requires more careful X-ray tube positioning to avoid grid cutoff of the primary radiation beam. (05 Mar 2000) |
| Wetzel grid | Chart of growth, plotting height, weight, physical fitness and related aspects of young and adolescent children during growth. (05 Mar 2000) |
| focused grid | A grid in which the divergent beam of X-rays from a particular distance range will be parallel to the lead strips. (05 Mar 2000) |
| radiographic parallel line shadows | The images of bronchial walls, usually thickened; colloq., British. Synonym: radiographic parallel line shadows. (05 Mar 2000) |
| parallel | 1. Pertaining to straight lines or planes that do not intersect. 2. <physics> Pertaining to electric circuit components connected in parallel so that the current flow divides, each branch passing through one component and rejoins, applied by extension to any similar parallel circuit, for example the systemic circulation to the various organs. (18 Nov 1997) |
| parallel attachment | A frictional or mechanically retained unit used in fixed or removable prosthodontics, consisting of closely fitting male and female parts, an attachment that may be rigid in function or may incorporate a movable stress control unit to reduce the torque on the abutment. Synonym: frictional attachment, internal attachment, key attachment, keyway attachment, parallel attachment, slotted attachment. (05 Mar 2000) |
| Parallel Electron Energy Loss Spectroscopy | <technique> Electron energy loss spectroscopy analyses the inelastically scattered electrons present in the beam after it has been transmitted through the sample. An electron energy loss spectrum typically consists of a monatomic decreasing background on which are superimposed a number of peaks. Each peak is characteristic of the scattering process that has occurred in the sample. The peaks can be used to obtain information about the chemical composition and electronic structure of the sample. Electron energy loss spectra are acquired typically in a magnetic sector spectrometer located under the camera chamber of the transmission electron microscope. Spatial resolution is typically limited by the minimum probe diameter of the microscope. Electron energy loss spectroscopy tends to be complimentary to EDS in that it can be used to analyse very thin samples of low Z materials. Acronym: PEELS (05 Aug 1998) |
| parallel rays | Ray's parallel to the axis of an optical system. (05 Mar 2000) |
| parallel track | <pharmacology> A system for distributing certain experimental drugs to people who are unable to participate in ongoing clinical trials. (09 Oct 1997) |
| plane-parallel | <optics> Having opposite surfaces exactly plane and parallel, as a piece of glass. Source: Websters Dictionary (01 Mar 1998) |
| second parallel pelvic plane | The plane extending from the middle of the posterior surface of the pubic symphysis to the junction of the second and third sacral vertebrae, and laterally passing through the ischial bones over the middle of the acetabulum. Synonym: second parallel pelvic plane, wide plane. (05 Mar 2000) |
| third parallel pelvic plane | The plane that extends from the end of the sacrum to the inferior border of the pubic symphysis; it is bounded posteriorly by the end of the sacrum, laterally by the ischial spines, and anteriorly by the inferior border of the pubic symphysis. Synonym: midplane, plane of least pelvic dimensions, plane of midpelvis, third parallel pelvic plane. (05 Mar 2000) |
| extinction parallel | <microscopy> Vibration directions parallel and perpendicular to the long direction of the crystal or fibre. (05 Aug 1998) |