La modified lead zirconate titanate ceramics (Pb0.92La0.08)(Zr0.95Ti0.05)O3 = PLZT-8/95/5 were prepared using the conventional solid state reaction method in order to investigate the complex impedance characteristics of the PLZT-8/95/5 ceramic according to temperature. The complex impedance in the PLZT-8/95/5 ceramic was measured over a temperature range of 30~550 °C at several frequencies. The complex dielectric constant anomaly of the phase transition was observed near TU1 = 179 °C and TU2 = 230 °C. A remarkable diffuse dielectric constant anomalous behaviour of the complex dielectric constant was found between 100 °C and 550 °C. The complex impedance spectra below and above TU1 and TU2 were fitted by the superposition of two Cole-Cole types of impedance relaxations. The fast component in the higher frequency region may be due to ion migration in the bulk, and the slow component in the lower frequency region is interpreted to be the formation and migration of ions at the grain boundary or electrode/crystal interfacial polarization.

We present a test of the emission statistics of active galactic nuclei (AGN), probing the connection between red-noise temporal power spectra and multi-modal flux distributions known from observations. We simulate AGN lightcurves under the assumption of uniform stochastic emission processes for different power-law indices of their power spectra. For sufficiently shallow slopes (power-law indices β≤ 1), the flux distributions (histograms) of the resulting lightcurves are approximately Gaussian. For indices corresponding to steeper slopes (β≥ 1), the flux distributions become multi-modal. This finding disagrees systematically with results of recent mm/radio observations. Accordingly, we conclude that the emission from AGN does not necessarily originate from uniform stochastic processes even if their power spectra suggest this. Possible mechanisms are transitions between different activity states and/or the presence of multiple, spatially disconnected, emission regions.

Environment-friendly soybean planting system has been being required in the upland field with high slope and heavy rain in summer season. Changes of weed amount and soybean yield by rye cover crop and conservation tillage were investigated. Soil-disturbing at conservation tillage before soybean planting increased numbers and dry weights of weeds germinated in late spring such as Echinochloa crusgalli P. Beauv (barnyardgrass) and Portulaca oleracea L. (common purslane) regardless of herbicide spray even though the weed, Chenopodium ficifolium Smith germinated before soil-disturbing were higher at non-disturbing soil. Higher weed amounts at plots of strip-tillage (30cm rototilling) compared to minimum tillage (10cm rototilling) was mainly due to the weed increase by soil-disturbing. Soybean yields at plots with rye cover crop, particularly early maturity rye cover crop, were lower than those at plots without rye cover crop, which was due to lower soybean seedling stand by heavy rye residue. More researches are required for the higher soybean yield at the minimum tillage with rye cover crop in which weed amounts were low.