Three sizes of nanocrystalline silver were investigated under high pressure in the diamond anvil cell using x-ray diffraction. The bulk modulus of each particle size was determined using least square fitting of the data to the Birch-Murnaghan equation of state. The bulk modulus of nanocrystalline silver was found to increase with decreasing particle size.;Three sizes of nanocrystalline silicon carbide were similarly investigated. There remains some uncertainty as to the correlation of particle size and compressibility, as the 20 nm SiC sample produced varying results upon repetition of the experiment.;Zirconium pyrophosphate, ZrP2O7, is a very low thermal expansion material, closely related to a class of negative thermal expansion materials. Raman spectroscopy was performed on the bulk form, under high pressure in the diamond anvil cell. In contrast to previously published work, evidence was found suggesting structural phase transitions around 1.2 GPa and 5.2 GPa. The substance became amorphous above 6 GPa and was pressure quenchable.
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