We report on the ability to use polarized light to measure the particle size distribution of thin layers of polystyrene microspheres on top of a solid Intralipid phantom. The optical properties of ...each layer were adjusted to match the absorption and scattering properties of the epidermis (polystyrene layer) and dermis (Intralipid layer). Polarized light was used to discriminate between light scattered from the top layer of polystyrene and the lower layer of Intralipid. In this paper we also study the effect of the thickness of the top layer on the ability to reconstruct the polystyrene size distribution.
We report here for the first time the detection of a seasonal variation in the occurrence of peaks in the spectra of energetic ∼ 100‐keV electrons precipitating from the inner radiation belt as the ...result of cyclotron resonance between the waves and the electrons. The spectra reported here were observed from the low‐altitude polar orbiting satellite P78‐1 at midnight local time. The data, acquired over the 5‐year period from March 1979 to July 1984, compose the first multiyear data set used to study cyclotron resonance peaks. The geographical distribution of the events is strongly clustered around the 22.3‐kHz VLF transmitter NWC in Australia. Binning the data into seasons, we find that the events occur 2.5 times more often during the 6 months from day 80 to 263 than during the remainder of the year and that the seasonal difference is statistically significant at a high level. Since the observed change is in the frequency of occurrence of the peaks and not in the mean energy of the peaks, we attribute the effect to a seasonal change in ionospheric transmission of VLF waves rather than a seasonal change in the equatorial cold plasma density.
