Scanning electron microscopy of impurity structures in snow

Abstract:

We examined well-sintered, mid-winter snow from Mammoth Mountain, California using an environmental scanning electron microscope equipped with a cold stage. Ring-like filaments were observed at all grain boundaries in a highly sublimated, sputter-coated sample 2 days after collection, though filaments were much harder to find in uncoated samples. Filaments appeared in uncoated specimens from the same snow sample five months later, though X-ray microanalysis failed to detect soluble impurities in the filaments, grain boundary grooves or on ice grain surfaces above background noise levels. After 8 months in storage and under forced sublimation in high vacuum, the same sample produced not only grain boundary filaments but complex, web-like structures, nodules and films that, in extreme cases, formed castings of completely sublimated snow grains. Energy dispersive X-ray spectrometry reveals that …

Año de publicación:

2007

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Fuente:

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