Accession Number : AD0257172

Title :   THE TIME CONSTANTS OF PEARL-CHAIN FORMATION

Corporate Author : PENNSYLVANIA UNIV PHILADELPHIA MOORE SCHOOL OF ELECTRICAL ENGINEERING

Personal Author(s) : SAITO,M. ; SCHWAN,H.P.

Report Date : DEC 1960

Pagination or Media Count : 1

Abstract : The time constants involved in the pearl-chain formation are of the order of a second for the radius of 1 micron, and they are porportional to the cube of the radius. The time constants are not strongly dependent on the field intensity when it is small, and they are inversely proportional to the square of the field intensity when it is large. The transition between the two regions occurs near the threshold. For particles of several microns or of larger sizes, the time constants become as large as hundreds of seconds, and consequently there exists a danger of observing erroneous threshold values in experimental works. The pulsed applied field is as effective as is expected from its r.m.s. value for usual radar systems. The hazards due to heat become pronounced before the field intensity is large enough for the pearl-chain to form if the particle size is less han 10 micron. The phenomenon of pearl-chain formation was considered of no biological significance in the area of microwave hazards due to radar exposure. (Author)

Descriptors :   *BIOPHYSICS, *COLLOIDS, DIELECTRIC PROPERTIES, EQUATIONS, FUNCTIONS(MATHEMATICS), HAZARDS, INTENSITY, MICROWAVES, PARTICLES, PHYSICAL CHEMISTRY

Distribution Statement : APPROVED FOR PUBLIC RELEASE