Temperature independence of piezoelectric properties for high-performance BiFeO3-BaTiO3 lead-free piezoelectric ceramics up to 300 °C.

The temperature-dependence behaviors of ferroelectric, piezoelectric, k p and electrical-field-induced strain were carefully evaluated for high-performance BiFeO3-0.3BaTiO3 (BF-0.3BT) ceramics. There results indicate, combined with Rayleigh analysis and temperature-dependence XRD and PFM, that the increase of strain and large signal with increasing the temperature from room temperature to 180 °C is related to the joint effect of intrinsic contribution (lattice expansion) and extrinsic contribution (domain switching). With further increasing the temperature to 300 °C, the large signal d 33 and electrical-field-induced strain mildly decrease because of the increase of conductivity for BF-0.3BT ceramics. However, different from strain and large signal the small signal d 33(E0) and k p exhibit excellent temperature stability behavior as the temperature increases from room temperature to 300 °C.

Significantly improved piezoelectric performance of PZT-PMnN ceramics prepared by spark plasma sintering.

A high-performance piezoelectric material, 0.95Pb(Zr0.52Ti0.48)O3-0.05Pb(Mn1/3Nb2/3)O3 (PZT-PMnN) ceramic, was prepared by using a spark plasma sintering (SPS) method. By systematically comparing the electrical properties, the spark-plasma-sintered sample was demonstrated to be superior to a conventionally sintered sample. With respect to conventionally sintered ceramic, the d 33 of spark-plasma-sintered ceramic increases from 323 pC/N to 412 pC/N, and the increases from 318 pm V-1 to 553 pm V-1. More importantly, the mechanical quality factor (Q m) reaches 583, which is three times higher than the conventionally sintered sample (Q m ∼ 182). Furthermore, the SPS method was found to be capable of promoting other electrical properties simultaneously. Therefore, the SPS method is proposed to be an effective processing method to fabricate PZT-PMnN ceramics of higher performance.

The survival mechanisms of thermophiles at high temperatures: an angle of omics.

Thermophiles are referred to as microorganisms with optimal growth temperatures of >60 °C. Over the past few years, a number of studies have been conducted regarding thermophiles, especially using the omics strategies. This review provides a systematic view of the survival physiology of thermophiles from an "omics" perspective, which suggests that the adaptive ability of thermophiles is based on a cooperative mode with multi-dimensional regulations integrating genomics, transcriptomics, and proteomics.

[Study on a bacterial strain Bt8 for biocontrol against citrus bacterial canker].

Citrus bacterial canker is an important disease of Citrus species in China. The disease severely occurs especially in the coastal area. Integrated control system has been used for the control of the disease, in which chemotherapy plays an important role at present. The chemotherapy-dominant control system brought many problems to the environment, such as chemical residua in the products and induction of resistance to fungicide(s) by the pathogen. To solve these problems, an intensive study on biocontrol of citrus bacterial canker is needed. Isolations and characterizations of biocontrol agents are the basis for biocontrol of the disease. A bacterial strain Bt8 with strong inhibiting ability against Xanthomonas axonopodis pv. citri (Hasse) Vauterin, was isolated from citrus orchard soil in Nanning, China. The isolated bacterial strain was identified and characterized as Acinetobacter baumannii Bouvet et Grimont on the base of its morphology and 16S rDNA sequence analysis as well as physiological and biochemical characters. The inhibiting activity of the bacterium suspension against the pathogen was significantly influenced by environmental factors, such as temperatures, pHs and media. At temperatures of 18 degrees C to 33 degrees C, both the inhibiting activity of the bacterium suspension and the biomass of the bacterium increased with the increases of temperatures, suggesting that the influence of temperature on inhibiting activity of the bacterium suspension was in dependence on the bacterial biomass. In NA liquid medium of pH 10, the bacterium suspension showed the highest inhibiting activity against Xanthomonas axonopodis pv. citri, which was not in dependence on biomass of the bacterium. The bacterium suspension provided 55.2% inhibition against bacterial canker under greenhouse conditions. The results showed that Acinetobacter baumannii has potential as biocontrol agent against bacterial canker disease. Acinetobacter baumannii was reported as the pathogens infecting human and animals. The present study enriched the understanding on biological diversity in Acinetobacter baumannii to sciences. This is the first report on the isolation of Acinetobacter baumannii with strong inhibiting ability against plant pathogen.