| vibration | 1. The act of vibrating, or the state of being vibrated, or in vibratory motion; quick motion to and fro; oscillation, as of a pendulum or musical string. "As a harper lays his open palm Upon his harp, to deaden its vibrations." (Longfellow) 2. <physics> A limited reciprocating motion of a particle of an elastic body or medium in alternately opposite directions from its position of equilibrium, when that equilibrium has been disturbed, as when a stretched cord or other body produces musical notes, or particles of air transmit sounds to the ear. The path of the particle may be in a straight line, in a circular arc, or in any curve whatever. Vibration and oscillation are both used, in mechanics, of the swinging, or rising and falling, motion of a suspended or balanced body; the latter term more appropriately, as signifying such motion produced by gravity, and of any degree of slowness, while the former applies especially to the quick, short motion to and fro which results from elasticity, or the action of molecular forces among the particles of a body when disturbed from their position of rest, as in a spring. Amplitude of vibration, the maximum displacement of a vibrating particle or body from its position of rest. Phase of vibration, any part of the path described by a particle or body in making a complete vibration, in distinction from other parts, as while moving from one extreme to the other, or on one side of the line of rest, in distinction from the opposite. Two particles are said to be in the same phase when they are moving in the same direction and with the same velocity, or in corresponding parts of their paths. Origin: L. Vibratio: cf. F. Vibration. Source: Websters Dictionary (01 Mar 1998) |
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| vibration syndrome | <syndrome> Tingling, numbness, and blanching of the fingers resulting from use of hand-held vibration tools; may persist without further exposure to vibration. (05 Mar 2000) |
| vibration tolerance | The maximum vibratory or oscillatory movements that an individual can experience and bear without pain; the limit of tolerance is a function of amplitude and frequency of the vibration and varies with the direction of application. (05 Mar 2000) |
| bounce frequency | <physics> The average frequency of oscillation of a particle trapped in a magnetic mirror as it bounces back and forth between its turning points in regions of high magnetic field. (See also trapped particle, turning points, banana orbit). (09 Oct 1997) |
| radio frequency current drive | <radiobiology> Plasma waves in the radio-frequency range can be used to push plasma particles in such a way that current forms in the plasma, this is a method of non-inductive current drive which would allow for steady-state fusion reactors to operate. (09 Oct 1997) |
| radio frequency heating | <radiobiology> Process for heating the plasma by transferring energy to ions or electrons using waves generated by an external oscillator at an appropriate frequency. (This is similar to how a microwave oven heats food.) There are various types: See: ECRH, ICRH, and Lower Hybrid. (09 Oct 1997) |
| radio frequency or radiofrequency | <physics> Term used to describe electromagnetic radiation with frequencies less than infrared, but greater than audio frequencies, i.e., greater than about 15,000 Hz. Wavelengths are therefore less than about 20,000 km and greater than about 0.01 mm. (These numbers are not precise.) (09 Oct 1997) |
| gene frequency | The relative occurence (expressed as a percentage) of a gene in a given population. (09 Oct 1997) |
| recombination frequency | The frequency at which crossingover occurs between two chromosomal loci--the probability that twoloci will become unlinked during meiosis. (09 Oct 1997) |
| resonant frequency | The frequency at which individual magnetic nuclei absorb or emit radiofrequency energy in magnetic resonance studies. Synonym: resonance. (05 Mar 2000) |
| respiratory frequency | The number of breaths per minute. (05 Mar 2000) |
| collision frequency | <chemistry> The rate at which chemical species collide, used in theories of chemical kinetics. Also, the frequency with which gaseous molecules collide. (09 Oct 1997) |
| plasma frequency | <radiobiology> The natural collective oscillation frequency of a charge species (electrons, ions, etc.) in a plasma, in the absence of (or at least parallel to) a magnetic field. Also known as Langmuir or Langmuir-Tonks frequency. See: electrostatic waves, plasma oscillations. (09 Oct 1997) |
| mutational frequency | The proportions of mutations in a population. (05 Mar 2000) |
| critical flicker fusion frequency | The minimal number of flashes of light per second at which an intermittent light stimulus no longer stimulates a continuous visual sensation. (05 Mar 2000) |