| MRI | Magnetic Resonance Imaging; 자기 공명 영상 |
|---|---|
| fMRI | functional magnetic resonance imaging |
| MRI | machine-readable identifier; magnetic resonance imaging; medical records information; Medical Resear... |
| MRSI | magnetic resonance spectroscopy imaging |
| NMRI | Naval Medical Research Institute; nuclear magnetic resonance imaging |
| ligand gated ion channel | A transmembrane ion channel whose permeability is increased by the binding of a specific ligand, typically a neurotransmitter at a chemical synapse. The permeability change is often drastic, such channels let through effectively no ions when shut, but allow passage at up to 10exp7 ions sexp 1 when a ligand is bound. Recently, the receptors for both acetylcholine and GABA have been found to share considerable sequence homology, implying that there may be a family of structurally related ligand gated ion channels. (18 Nov 1997) |
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| magnetic | 1. A magnet. "As the magnetic hardest iron draws." (Milton) 2. Any metal, as iron, nickel, cobalt, etc, which may receive, by any means, the properties of the loadstone, and which then, when suspended, fixes itself in the direction of a magnetic meridian. Source: Websters Dictionary (01 Mar 1998) |
| magnetic attraction | The force that draws iron or steel toward a magnet. (05 Mar 2000) |
| magnetic axis | <physics> This typically refers to the location of the innermost flux surface in a toroidal device, the one which encloses no volume and has therefore degenerated from a flux surface into a single field line. Roughly, the circle through the middle of the dough of the donut. Additionally, in systems with magnetic islands (see entry below), each island has a local magnetic axis, distinct from the overall magnetic axis of the torus. (09 Oct 1997) |
| magnetic confinement | <physics> Use of magnetic fields to confine a plasma. (Confinement involves restricting the volume of the plasma and/or restricting particle or energy transport from the centre of the plasma to the edge.) (09 Oct 1997) |
| magnetic confinement fusion | <physics> Method of fusion which uses magnetic fields / magnetic bottles to confine a hot plasma until fusion occurs. (09 Oct 1997) |
| magnetic field | The sphere of influence of a magnet. (05 Mar 2000) |
| magnetic field gradient | In magnetic resonance imaging, a magnetic field that varies with location, superimposed on the uniform field of the magnet, to alter the resonant frequency of nuclei and allow recovery of their spatial position. Synonym: field gradient. (05 Mar 2000) |
| magnetic implant | A tissue-tolerated, magnetised metal placed within the bone to aid in denture retention; a similar magnet is placed in the overlying denture to complete the field. (05 Mar 2000) |
| magnetic inertia | <physics> A lagging or retardation of the effect, when the forces acting upon a body are changed, as if from velocity or internal friction; a temporary resistance to change from a condition previously invuced, observed in magnetism, thermoelectricity, etc, on reversal of polarity. Origin: NL, fr. Gr. To be behind, to lag. Source: Websters Dictionary (01 Mar 1998) |
| magnetic island | <physics> A magnetic topology near a rational surface where the flux surface is broken up into tubes which are not connected with each other poloidally. Islands may develop in non-ideal magnetohydrodynamic fluids, where electrical resistance becomes important and magnetic field lines are no longer frozen-in to the fluid. Then magnetic tearing and reconnection may allow field lines to link up and form islands with a local magnetic axis in a narrow region near a rational surface. (See also magnetohydrodynamic, frozen-in law). The development of islands may be caused by a small perturbation, whether internal or external, whether deliberate or accidental, and is usually associated with enhanced transport (i.e., reduced confinement). The centres of the islands are magnetic O-points, while the boundaries between islands are marked by X-points. (09 Oct 1997) |
| magnetic mach number | <physics> A dimensionless number equal to the ratio of the velocity of a fluid to the velocity of Alfven waves in that fluid. (13 Nov 1997) |
| magnetic moment | <physics> (a) A vector associated with a magnet, current loop, or particle, the cross product of this vector with the magnetic field is equal to the torque which the field exerts on the system. (b) The adiabatic invariant associated with the rapid gyromotion of a charged particle in a slowly varying magnetic field. (The value of the magnetic moment in sense (b) is the magnitude of the vector in sense (a).) (13 Nov 1997) |
| magnetic probe | <radiobiology> A conducting coil (sometimes insulated and inserted into the plasma) will have an induced voltage due to changes in the magnetic flux through the coil, and can therefore be used to measure changes in magnetic field strength. Small coils used to measure the local field strength are known as probes. (Other plasma diagnostics using this effect are the Rogowski coil, the voltage loop, and the diamagnetic loop.) Magnetic probes placed outside a toroidal plasma which are used to measure the poloidal magnetic field are also called Mirnov coils. (09 Oct 1997) |
| magnetic pumping | <radiobiology> Form of plasma heating where the plasma is successively compressed and expanded by means of a fluctuating external magnetic field. (See also adiabatic compression, frozen-in law.) (09 Oct 1997) |