The piezoelectric ceramics xPb(Mn1/3Sb2/3)O3-(1-x)Pb(Zr1/2Ti1/2)O3 (abbreviated as PMS-PZT) were synthesized by traditional ceramics process. The effect of sintering temperature and the amount of Pb(Mn1/3Sb2/3)O3 (abbreviated as PMS) on phase structure, microstructure, piezoelectric and dielectric properties of PMS-PZT ceramics was investigated. The results show that the pure perovskite phase is in all ceramics specimens, the phase structure of PMS-PZT ceramics changes from tetragonal phase to single rhombohedral phase with the increasing amount of PMS. The dielectric constant εr, Curie temperature TC, electromechanical coupling factor kp and piezoelectric constant d33 decrease, whereas the mechanical quality factor Qm and dielectric loss tanδ increase with the increasing amount of PMS in system. The optimum sintering temperature is 1 200?1 250 ℃. It is concluded that the PMS-PZT (x=0.07) ceramics sintered at 1 250 ℃ is suitable for high-power piezoelectric transformer. These properties include εr= 674.8, tanδ=0.005 25, kp=0.658, Qm=1 520, d33=230 pC/N, Tc=275 ℃.
By making a comparison between the acoustic equations and the 2-dimensional(2D) Maxwell equations,we obtain the material parameter equations(MPE) for acoustic elliptical cylindrical cloaks.Both the theoretical results and the numerical results indicate that an elliptical cylindrical cloak can realize perfect acoustic invisibility when the spatial distributions of mass density and bulk modulus are exactly configured according to the proposed equations.The present work is the meaningful exploration of designing acoustic cloaks that are neither sphere nor circular cylinder in shape,and opens up possibilities for making complex and multiplex acoustic cloaks with simple models such as spheres,circular or elliptic cylinders.
