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Summary For the first time a scanned focused ion beam of approximately 50 nm diameter has been used to prepare biological material. Small defined areas of the surface were removed by ion etching to allow examination of the underlying structures with a scanning electron microscope. Different milling procedures were carried out on two anatomical features in mites of the genus Halarachne (Halarachnidae: Mesostigmata). In the first, square holes were milled into the surface of the peritrematal plate to reveal the structure of the underlying respiratory peritrematal groove. In the second, transverse cuts were made across the shafts of the sensory sensilli which make up the sensory Haller's organ on tarsus I. This latter procedure revealed detail both within the core and walls of sensilli. Details of specimen preparation and milling procedures, as well as suitability and interpretation of results, are presented.

Raman spectroscopy has been used to characterise the structure of three very different particulate composite systems: aramid particles in nylon 6.6, cast iron (graphite particles in an iron matrix) and C 60 or carbon nanotubes in an epoxy resin matrix. In addition, Raman spectroscopy has been used to follow the stressinduced tensile deformation of the particles within the composite matrices. It is shown that, for the different composite systems, certain Raman band positions move to lower wavenumber upon the application of a tensile strain and that the rate of this Raman band shift gives an indication of the level of reinforcement from the dispersed particulate phase. In each case stress transfer between the matrix and particles is observed but, in general, it is demonstrated that particulate reinforcement is not as efficient as fibre reinforcement.

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