No abstract

No abstract

No abstract

Chemically deposited PbS thin films have been prepared for use as infrared detectors. A systematic and elaborate study using scanning electron microscopy shows that the structure and crystallite size are related to the photosensitivity. Both the role of chemical oxidant influencing the type of conductivity and morphological details such as crystallite size distribution have been investigated. It is observed that in the absence of oxidant the average size of crystallites is about 0.9 pm. This decreases to 0.3 pm for the concentration of oxidant imparting maximum photosensitivity and further reduces to 0.2 pm or less at higher concentrations. A good photosensitive film is electronically p-type and has a more uniform crystallite size distribution with relatively loose compact structure. Annealing of the films at 393 K under vacuum (5 x Torr) for 4-5 h affects the electronic properties considerably but does not cause any appreciable change in the structure except in smoothing the grain boundaries to a certain extent. A qualitative explanation in terms of rate of chemical reaction is offered for the morphological parameters observed in these experiments. It is also suggested that the photocharacteristics could be viewed partly as a support for barrier modulation but having its origin in the physical nature of the films.

Soybean trypsin inhibitor (STI) is a known antinutrient and food allergen present in soybean. γ-Radiation has the potential to inactivate the TI protein. However, a systematic study on the influence of different moisture levels during γ radiation on structure and function of the molecule has not been reported. Pure STI was irradiated up to 200 kGy, in dry state, with 50% moisture and in aqueous solution. The radiation damage in molecular structure was assessed using, SDS-PAGE, size exclusion chromatography, fluorescence measurement, and circular dichroism, while functional damage was assessed by the TI assay. In aqueous solution, both the structure and function of TI were almost destroyed at the 10 kGy dose. While with 50% moisture and in dry state, the loss in functional and structural attributes was discernible only at 30 and 100 kGy, respectively. The TI activity was found to be unaffected in dry and soaked seeds of soybean as well as other legumes up to irradiation doses of 100 and 50 kGy, respectively.