| RF | radial fiber; radio frequency; receptive field; regurgitant fraction; Reitland-Franklin [unit]; rela... |
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| CHFV | combined high-frequency ventilation |
| EHF | epidemic hemorrhagic fever; exophthalmos-hyperthyroid factor; extreme high frequency |
| hf | half; high frequency |
| HFC | hard filled capsule; high-frequency current; histamine-forming capacity |
| nearest neighbor frequency | The frequency by which certain types of entities or structures are immediately adjacent to a given structure. (05 Mar 2000) |
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| dominant frequency | The frequency occurring most often in an electroencephalogram. (05 Mar 2000) |
| flicker fusion frequency technique | A technique of perimetry using the criterion of critical fusion frequency. Synonym: flicker fusion frequency technique. (05 Mar 2000) |
| Larmor frequency | In magnetic resonance, the precessional frequency, n0, of magnetic nuclei in a plane perpendicular to the direction of the external magnetic field; v0 = gB0/2π, where B0 is the magnetic field strength and g is the magnetogyric ratio. (05 Mar 2000) |
| frequency | 1. <physics> The number of occurrences of a periodic or recurrent process per unit time, for example the number of vibrations of a particle per second or the number of repetitions of a complete wave form (cycles) per second. 2. <statistics> The number of members of a population or statistical sample falling in a particular class. 3. Relative frequency, the average number of occurrences of a particular event in a large number of repeated trials. (07 Apr 1998) |
| frequency analysis | <ecology, statistics> A method of evaluating vegetation in an area by establishing a transect and counting the occurrences of plant species at various sampling points along the transect. (07 Apr 1998) |
| frequency curve | A systematic grouping of data into classes or categories according to the frequency of occurrence of each successive value or ranges of such values, resulting in a graph of a frequency distribution. Synonym: frequency curve. (05 Mar 2000) |
| frequency distribution | A statistical description of raw data in terms of the number or frequency of items characterised by each of a series or range of values of a continuous variable. (05 Mar 2000) |
| frequency domain | The expression of a function by its amplitude and phase at each component frequency, usually as determined by Fourier analysis. (05 Mar 2000) |
| frequency encoding | In magnetic resonance imaging, a method of varying the magnetic field strength with location to encode the location of each voxel uniquely in one direction. (05 Mar 2000) |
| frequency of micturition | Micturition at short intervals; it may result from increased urine formation, decreased bladder capacity, or lower urinary tract irritation. (05 Mar 2000) |
| frequency of occurrence | The number of times a given event occurs at specified sample points during a defined period. (07 Apr 1998) |
| frequency spectrum | The range of frequencies in a signal, used to describe the resolving power of an imaging system in radiology. (05 Mar 2000) |
| frequency, urinary | Urinating too often, at too frequent intervals, not due to an unusually large volume of urine, but rather to a decrease in the capacity of the bladder to hold urine. (12 Dec 1998) |
| fundamental frequency | The principal component of a sound wave, which has the greatest wavelength, tone produced by the vibration of the vocal folds before the air reaches any cavities. (05 Mar 2000) |