Solid-state synthesis and characterisation of mesoporous zirconia with lamellar and wormhole-like mesostructures

Mesostructured zirconia with lamellar and wormhole-like mesostructure was synthesized using a solid-state reaction route. Ordered lamellar mesostructure is achieved at low OH–/Zr ratio; while high OH–/Zr ratio leads to less ordered wormhole-like mesostructure. The varying synthesis conditions result in different inorganic frameworks with amorphous (in lamellar mesostructure) or tetragonal phase pore walls with different thermal stability. The surface area and pore structure of zirconia prepared by this method can be tailored using simple synthesis parameters such as OH–/Zr ratio and crystallization temperature. High surface area up to 716 m2/g can be achieved in the lamellar structured zirconia. However, the wormhole- like structured zirconia possesses high thermal stability. The results strongly suggest that in solid-state synthesis system mesostructure formation still follows the supramolecular self-assembly mechanism. In such synthesis system, the lamellar and reverse hexagonal structure can be transformed at different OH–/Zr ratios in order to minimize the surface energy of the mesophases formed

LONG-TERM AND SHORT-TERM CONTRACT IN A MIXED MARKET *

With a two-period mixed oligopolistic framework, this paper analyses the interaction between the length of incentive contracts and market behaviour. Assuming an environment in which firms choose either a long-term or short-term contract, we examine how contracts differ between public and private firms. The results show that the contracts would differ completely among firms; public firm prefers to make a short-term contract while private firm makes a long-term contract. Copyright Blackwell Publishing Ltd/University of Adelaide and Flinders University 2005..