Porous hydroxyapatite bioceramics were obtained by impregnating the polyurethane sponge with rheologically optimized slurry. 6wt% bioglass was doped into hydroxyapatite to act as a sintering additive. Thermal analysis was used to study the pyrolysis process of the polyurethane sponge. Phase component and surface morphology were characterized by X-ray diffraction and scanning electron microscopy, respectively. It was found that hydroxyapatite was the main phase composition of the porous ceramics sintered at 1250°C. The porous bodies prepared had an open, uniform and interconnected structure with pore size of 200-400μm. The porous ceramics possessed high porosity of 70-80% and compressive strength of 2.3MPa. The precipitates formed on the surface of the porous ceramics might be bone-like apatite after immersion in a simulated body fluid for various periods.

No abstract

Over the past decade, complex dynamical network synchronization has attracted more and more attention and important developments have been made. In this paper, we explore the scheme of globally exponentially asymptotical synchronization in complex dynamical networks with time delay. Based on Lyapunov stability theory and through defining the error function between adjacent nodes, four novel adaptive controllers are designed under four situations where the Lipschitz constants of the state function in nodes are known or unknown and the network structure is certain or uncertain, respectively. These controllers could not only globally asymptotically synchronize all nodes in networks, but also ensure that the error functions do not exceed the prescheduled exponential function. Finally, simulations of the synchronization among the chaotic system in the small-world and scale-free network structures are presented, which prove the effectiveness and feasibility of our controllers.

Two-liquid bimetal composite casting technology by double induction furnace fusion was utilized for preparing bimetal product in tradition. Single induction furnace fusion has been investigated between the high carbon steel and the low carbon steel, and varying casting thickness has an obvious effect on the bimetal bonding layer. The results have shown that the bimetal bonding layer can not been generated under over thinness or thickness. In the condition of the thicker low carbon steel, two kinds of metal liquid were easy to rush mixture without the distinct interface, whereas the thinner low carbon steel can also effectively form metallurgical bonding. While the low carbon steel owned the proper thickness, metallurgical bonding can been observed distinctly, confirming the feasibility of the single induction fusion for preparing the bimetal.

No abstract