The pressure-transmitting behavior and pressure distribution of a pyrophyllite cell in a cubic-anvil large volume high-pressure apparatus is investigated by finite-element analysis (FEA). The mechanical equations describing pyrophyllite under high pressure are given, which are composed of the Drucker-Prager criterion and a linear equation of state. The related material parameters such as cohesive strength, angle of internal friction etc. are experimentally measured. The FEA simulation includes the non-uniformity deviatoric stress caused by plastic deformation and the isotropy hydrostatic pressure of the pyrophyllite cell caused by volume compression. The results demonstrate that, in such a pyrophyllite cell, almost 90% of the pressure is isotropy hydrostatic pressure, and the pressure gradient mainly arise from non-uniform deviatoric stresses. Simulated data are displayed using the contour and the path plots.

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surface chemistrysurface chemistry G 7000 -026Changes of the Surface State of TiO2 in the Preparation of Sulfate Promoted Titanium Oxide -by calcining (NH4)2SO4 on anatase are investigated by IR spectroscopy, XPS, as well as acid-catalyzed esterification and acid strength measurements. It is shown that (NH4)2SO4 at temp. ¡ 523 K ( decomposition temp.) can disperse spontaneously on TiO2 as a monolayer followed by the formation of a S-Ti species, which is responsible for the super-acidity and the catalytic activity of the promoted TiO2. -(LI, R.; YANG, H.; ZHANG, W.; WEI, Q.; Z.