Thickness effect on the dielectric, ferroelectric, and piezoelectric properties of ferroelectric lead zirconate titanate thin films Effects of postdeposition annealing on the dielectric properties of antiferroelectric lanthanum-doped lead zirconate stannate titanate thin films derived from pulsed laser deposition

A new process for solar grade silicon production by molten salt electrolysis has been proposed and its feasibility discussed. This process consists of an electrolysis step of SiO 2 dissolved in a fluoride melt using an aluminum-silicon liquid alloy cathode and a precipitation step of silicon from the liquid alloy. According to the calculation based on literature data, the proposed process has the possibility to produce solar grade silicon in combination with directional solidification, even if the electrolysis step has no purification effect. A preliminary electrolysis using aluminum cathode and carbon anode in a NaF-AlF 3 -SiO 2 melt at 1273 K revealed that silicon was formed by the electrolysis and that sub-reactions, such as the reduction of SiO 2 by aluminum and metal fog formation, also took place. Especially, SiO 2 reduction by aluminum was found to be fast compared to the reduction by the electrolysis, which made it difficult to evaluate the current efficiency. Thus, these sub-reactions were further investigated in order to measure the reaction rates, and their potential dependence. Based on the obtained data, the cathodic current efficiency during the preliminary electrolysis was evaluated to be greater than 46%.

Lead titanate, barium titanate, and lead barium titanate powders (>99.9% pure), the particle size of which varied from 0.03 to 0.15 pm depending on the calcination temperature and the composition, was prepared from barium lead titanyl oxalate, which was previously prepared by reacting high-purity ammonium titanyl oxalate with barium and lead acetate. The critical crystallite size of BaTiO, powder from the cubic to the tetragonal phase is around 1 pm. Pb,,,B%,,TiO, powder with an average size of 0.057 pm showed the tetragonal phase.

We derive a new method for initial-state collinear showering in Monte-Carlo event generators which is based on the use of unintegrated parton correlation functions. Combined with a previously derived method for final-state showering, the method solves the problem of treating both the hard scattering and the evolution kernels to be used in arbitrarily non-leading order. Although we only treat collinear showering, so that further extensions are needed for QCD, we have discovered several new results: (1) It is better to generate exact parton kinematics in the hard scattering rather than with the subsequent parton showering, and similarly at each step of the showering. (2) Parton showering is then done conditionally on the exact energy-momentum of the initiating parton. (3) We obtain a factorization for structure functions in terms of parton correlation functions so that parton kinematics can be treated exactly from the beginning. (4) We obtain two factorization properties for parton correlation functions, one in terms of ordinary parton densities and one, suitable for event generation, in terms of parton correlation functions themselves.