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Effect of lattice occupation behavior of Li+ cations on microstructure and electrical properties of (Bi1/2Na1/2)TiO3-based lead-free piezoceramics J. Appl. Phys. 109, 054102 (2011) The effect of Nd substitution on the microstructures and electrical properties of Aurivillius phase ferroelectric Bi 3 NbTiO 9 -based ceramics has been studied. All of the Bi 3−x Nd x NbTiO 9 ͑0 Յ x Յ 1͒ ceramics are ferroelectrics. The Curie point T C decreased with increasing Nd doping content x. The Bi 3−x Nd x NbTiO 9 ceramics exhibited a sharp ferroelectric-paraelectric phase transition at small x values ͑x Յ 0.6͒, whereas a diffuse phase transition was observed at higher x values ͑x Ն 0.8͒. Both the piezoelectric constant d 33 and the dc electrical resistivity of Bi 3 NbTiO 9 ceramics were greatly enhanced by Nd substitution on the A sites. The improved properties can be attributed to the fact that Nd substitution depressed the generation of oxygen vacancies. A combination of high d 33 values, high resistivity, and high T C points ͑Ͼ700°C͒ suggests that the Bi 3−x Nd x NbTiO 9 ceramics with x Յ 0.6 could be good candidates for high-temperature piezoelectric applications.

The wheat stem sawfly (WSS) ( Cephus cinctus Norton) is a major yield-reducing pest of wheat ( Triticum aestivum L.). Varieties with pith-filled, or solid, stems provide a measure of resistance by inhibiting larval survival inside the stem. Durum wheat ( Triticum turgidum L.) has resistance to the wheat stem sawfly even in the absence of known genes for stem solidness. To determine the genetic basis of resistance in durum wheat, a susceptible durum wheat, PI 41353, was identified from among 1,211 landrace accessions from around the world screened in WSS-infested sites. A recombinant inbred line (RIL) population of 105 individuals was developed from a cross of PI 41353 with a typically resistant variety, Pierce. The RIL were screened in a total of three WSS-infested locations in Montana over a two year period. A genetic map was constructed with 2,867 SNP-based markers. A quantitative trait locus (QTL) analysis identified six QTL associated with resistance. An allele from resistant cultivar Pierce at a QTL on chromosome 3A, Qss.msub-3AL , caused a 25% reduction in stem cutting. Assessment of near-isogenic lines that varied for alleles at Qss.msub-3AL showed that the Pierce allele was also associated with higher stem solidness as measured early in stem development, which is a critical stage for WSS oviposition and larval development. Stem solidness of Pierce and other resistant durum wheat lines largely disappeared later in plant development. Results suggest a genetic mechanism for WSS resistance observed in durum wheat, and provide an additional source of WSS resistance for hexaploid bread wheat.

The toxicity of copper (Cu) and nickel (Ni) to bok choy and tomato shoot growth was investigated in a wide range of Chinese soils with and without leaching with artificial rainwater. The results showed that the variations of Ni toxicity induced by soil properties were wider than those of Cu toxicity to both tomato and bok choy plant growth. Leaching generally decreased the toxicity of Cu and Ni added to soils, which also depended on soils, metals, and test plant species. Soil factors controlling metal phytotoxicity were found to be soil pH and soil organic carbon content for Cu, and soil pH for Ni. It was also found that soil pH had stronger effects on Ni toxicity than on Cu toxicity. Predictive toxicity models based on these soil factors were developed. These toxicity models for Cu and Ni toxicity to tomato plant growth were validated using an independent data set for European soils. These models could be applied to predict the Cu and Ni phytotoxicity in not only Chinese soils but also European soils.