Ultrafine Pb0.93La.07Zr0.60Ti0.40O3 powder was synthesized by autoignition of a metal−polymer gel precursor on a hot plate at very low temperatures without an additional calcination step. The X-ray diffraction result of the as-burnt powder obtained after ignition showed the presence of rhombohedral lead lanthanum zirconate titanate (PLZT) with minute amounts of unreacted PbO. The average particle size calculated from the transmission electron microscopy micrograph of the as-burnt powder was 1.75 nm. The as-burnt ultrafine PLZT powder was sintered directly to 94 and 96% of its theoretical density at 1100 and 1200 °C without any additional calcination. The PLZT sample with 94% theoretical density and grain sizes 0.4−1.0 μm showed a very high dielectric permittivity of ∼5000 and a completely diffused phase transition near the Curie point. This sample exhibited a remnant polarization (P r) of ∼34.6 μc/cm2. The permittivity of the 1200 °C sintered sample decreases drastically to ∼800. Both of the sintered samples showed very low dielectric loss.

An experimental and theoretical study is presented of the properties of circumferential waves on thin-walled elastic, air-filled cylindrical shells immersed in water, and of their excitation by normally incident acoustic pulses of short duration. A spectral decomposition of the multiple echo pulses using the Numrich-de Billy method, and subsequent analysis by the resonance scattering theory (RST), reveal for an aluminum shell the presence of an •= 2 wave that can be identified with the So Lamb wave on a plate, and of an •= 0 wave that at low frequencies corresponds to a water-borne circumferential wave, not given by the Lamb theory of free-plate vibrations but by its extension to a plate with one-sided fluid loading. Calculations of complex pole resonances on aluminum and steel shells, as well as of the corresponding circumferential wave speeds and attenuations, serve to clarify the physical situation.

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We assess the usefulness of patent statistics as an indicator of innovation, using a direct measure of innovation in the hard disk industry (1976–1998). Three findings emerge: (i) patents “predict” innovations better than a random guess, and a simple refinement makes them more useful; (ii) conditional on actually innovating, conglomerates and larger firms patent more than specialised startups and smaller firms; and (iii) patent reforms seem to make the patent–innovation relationship nonstationary. These results suggest that researchers should use caution when comparing patents of different types of firms and across years.