487 research outputs found

    Mechanical performance of 22SiMn2TiB steel welded with low-transformation-temperature filler wire and stainless steel filler wire

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    TX-80 low-transformation-temperature (LTT) welding wire was used to replace the traditional ER 307Si welding wire to realize the connection of 22SiMn2TiB armor steel in manual overlay welding. The previously existing issues, such as welding cracks, large welding deformation, and severe welding residual stress, were solved to ensure good strength and ductility requirements. In particular, with the same welding conditions, TX-80 LTT wire eliminates welding cracks. It reduces the welding deformation no matter the base pretreatment of pre-setting angle or no pre-setting angle. By comparison, it was found that the microstructure at the TX-80 weld is mainly composed of martensite and a small amount of retained austenite. In contrast, the microstructure of the ER 307Si weld consists of a large amount of austenite and a small amount of skeleton-like ferrite. The variation trend of residual stress and microhardness from the weld to the base were investigated and compared with the mechanical properties of base materials. The TX-80 and the ER 307Si tensile samples elongation is 6.76% and 6.01%, while the ultimate tensile strengths are 877 and 667 MPa, respectively. The average impact toughness at room temperature of the ER 307Si weld is 143.9 J/cm2, much higher than that of the TX-80 weld, which is only 36.7 J/cm2. The relationship between impact and tensile properties with microstructure species and distribution was established. In addition, the fracture surface of the tensile and the impact samples was observed and analyzed. Deeper dimples, fewer pores, larger radiation zone, and shear lips of TX-80 samples indicate better tensile ductility and worse impact toughness than those of ER 307Si weld.</p

    [3,5-Bis(benz­yloxy)phen­yl]methanol

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    In the title compound, C21H20O3, the two terminal phenyl rings are each approximately perpendicular to the central benzene ring, making dihedral angles of 84.40 (16) and 75.12 (15)°. The H atom of the hydr­oxy group is disordered over two positions with equal occupancies. The mol­ecules are linked by O—H⋯O hydrogen bonds, forming a chain along the a axis

    Genetic characterization of Toxoplasma gondii from Qinghai vole, Plateau pika and Tibetan ground-tit on the Qinghai-Tibet Plateau, China

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    Background The distribution of genetic diversity of Toxoplasma gondii in wildlife is of interest to understand the transmission of this parasite in the environment. Limited information on T. gondii genotypes has been reported in wildlife in China. The objective of this study was to carry out the genetic characterization of T. gondii isolates from wild animals on the Qinghai-Tibet Plateau. Methods Using PCR and multilocous polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) technology, we detected genetic diversity of T. gondii isolates from Qinghai vole, Plateau pika and Tibetan ground-tit in these regions. Results In total, 183 brain tissues of different wild animals, including 48 Qinghai vole (Microtus fuscus), 101 Plateau pika (Ochotona curzoniae) and 34 Tibetan ground-tit (Pseudopodoces humilis), were tested for T. gondii infection. 11 of these were found to be positive for the T. gondii B1 gene by PCR amplification. These positive DNA samples were typed at 10 genetic markers, including 9 nuclear loci (SAG1, 5’-and 3’-SAG2, alternative SAG2, BTUB, GRA6, L358, PK1, c22-8, c29-2), and an apicoplast locus Apico. Six were successfully genotyped at eight or more genetic loci, and were grouped to three distinct genotypes. Four samples belonged to ToxoDB Genotype #10 and the other two samples were identified as two new genotypes (http://toxodb.org/toxo/ webcite). Conclusions To our knowledge, this is the first report of genetic typing of T. gondii isolates in wildlife on the Qinghai-Tibet Plateau, China. The results show that there is a potential risk for the transmission of this parasite through the wildlife in this region. doi:10.1186/1756-3305-6-29
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