Irradiation

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irradiation

[i‚rād·ē′ā·shən]
(biophysics)
Subjection of a biological system to sound waves of sufficient intensity to modify their structure or function.
(engineering)
The exposure of a material, object, or patient to x-rays, gamma rays, ultraviolet rays, or other ionizing radiation.
(optics)
An optical illusion which makes bright objects appear larger than they really are.

Irradiation

 

in physiology, the spread of excitation or inhibition in the central nervous system. Irradiation plays an important part in cerebrocortical activity. The irradiation of excitation is manifested most distinctly after strong stimulation, when nerve centers usually not involved in a reflex response are drawn into the process. For example, moderate pain inflicted on the skin of an animal’s foot causes the paw to flex in the talocalcaneal joint. Increasing the force of stimulation causes the leg to flex in the knee and hip joints. In studying the effect of an inhibitory conditioned stimulus, I. P. Pavlov showed that inhibition can also spread (irradiate) in the cells of the cerebral cortex.


Irradiation

 

the apparent enlargement of the dimensions of white (light) objects against a black (dark) background (given the comparatively great brightness of the white object) or, conversely, the apparent diminution of the dimensions of black objects against a white background. (The first instance is called positive irradiation; the second, negative.)

As a result of irradiation, a thin black thread or wire observed against a bright flame seems to be interrupted in that segment, and the bright crescent of the new moon seems to have a larger diameter than the ash-gray disk of the moon seen simultaneously with it. The degree of irradiation increases when the brightness of the light background or object increases. Irradiation is caused by optical defects of the eye (spherical and chromatic aberrations), diffraction phenomena in the eye, and imperfect fixation of the eye on the objects observed.

REFERENCE

Kravkov, S. V. Glaz i ego rabota: Psikhofiziologiia zreniia, gigiena osvesh-cheniia, 4th ed. Moscow-Leningrad, 1950. (Includes bibliography.)
References in periodicals archive ?
Electron beam irradiation of the samples was done by electron-beam accelerator (model ELV 4, 2.
The concentration of hydrocarbons induced was found to increase in accordance to irradiation dose.
The reason for this high content of Cn-1 hydrocarbons than Cn-2, could be because of the hexane solvent interference as also determined the same for irradiation of meat and fish by Hwang et al 1997 [26].
Table-4: Concentrations (ug/g fat) of hydrocarbons induced by e-beam irradiation of jerky.
The sensory parameters were color, odor, taste, overall acceptability, and irradiation off- odor.
The Hunter color value changes of sliced and pizza cheeses by gamma and electron beam irradiation are shown in Table 1.
2007b) indicated that TBARS values increased as the increase of irradiation dose, but there was no significant difference between non-irradiated and irradiated (less than 3 kGy) cheddar cheese.
However, gamma and electron beam irradiation of sliced and pizza cheeses influenced all other sensory parameters.
The absorption spectra of bromo-chlorophenol blue, BCPB/PVA films containing different concentrations of chloral hydrate were recorded before and after irradiation to different doses.
Upon irradiation, these films change their color from blue (the alkaline form of the dye with lmax = 604 nm) to green and finally to yellow (the acid form of the dye with lmax = 440 nm) indicating acid formation.
1066phr) were recorded before and after irradiation to different doses and are shown in Fig.
It can be noticed that all curves have the same S-Shape, characteristic of the irradiation response of a pH indicator in an acid-base titration with different sensitivities.