Redox processes in highly yttrium-doped barium titanate

The changes of microstructure occurring during oxidation of the reduced form of yttrium-doped barium titanate have been studied. Samples were sintered under reduction conditions at and oxidized by annealing at high temperatures (1150 and 1350 °C) in air. Depending on yttrium concentration, the oxidation of the reduced form of the yttrium-doped BaTiO₃ caused precipitation of the phase Ba₆Ti₁₇O₄₀ or the phases Ba₆Ti₁₇O₄₀ and Y₂Ti₂O₇. The precipitates had well-defined orientational relationships with the perovskite matrix. Oxidation of the reduced form of doped barium titanate results in formation of the phase responsible for increase in the resistance of outer grain layers, which lie between grain boundaries and grain.     

Water molecules in a protein cavity detected by a statistical-mechanical theory

Four water molecules confined in a small cavity of hen egg-white lysozyme were detected by means of the three-dimensional (3D) RISM theory, a statistical-mechanical theory of molecular solutions. This is the first theoretical realization of confined molecules in a protein without making nonsense tricks, such as placing the molecules in the space a priori. Possible impacts which the result may have on biochemistry and biophysics, including the molecular recognition, enzymatic reactions, etc., are discussed.