An entry from the Inorganic Crystal Structure Database, the world’s repository for inorganic crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the joint CCDC and FIZ Karlsruhe Access Structures service and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
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Sulfate-reducing bacteria (SRB) have been studied extensively in the petroleum industry due to their role in corrosion, but very little is known about sulfur-oxidizing bacteria (SOB), which drive the oxidization of sulfur-compounds produced by the activity of SRB in petroleum reservoirs. Here, we surveyed the community structure, diversity and abundance of SRB and SOB simultaneously based on 16S rRNA, dsrB and soxB gene sequencing, and quantitative PCR analyses, respectively in petroleum reservoirs with different physicochemical properties. Similar to SRB, SOB were found widely inhabiting the analyzed reservoirs with high diversity and different structures. The dominant SRB belonged to the classes Deltaproteobacteria and Clostridia, and included the Desulfotignum, Desulfotomaculum, Desulfovibrio, Desulfobulbus and Desulfomicrobium genera. The most frequently detected potential SOB were Sulfurimonas, Thiobacillus, Thioclava, Thiohalomonas and Dechloromonas, and belonged to Betaproteobacteria, Alphaproteobacteria, and Epsilonproteobacteria. Among them, Desulfovibrio, Desulfomicrobium, Thioclava, and Sulfurimonas were highly abundant in the low-temperature reservoirs, while Desulfotomaculum, Desulfotignum, Thiobacillus, and Dechloromonas were more often present in high-temperature reservoirs. The relative abundances of SRB and SOB varied and were present at higher proportions in the relatively high-temperature reservoirs. Canonical correspondence analysis also revealed that the SRB and SOB communities in reservoirs displayed high niche specificity and were closely related to reservoir temperature, pH of the formation brine, and sulfate concentration. In conclusion, this study extends our knowledge about the distribution of SRB and SOB communities in petroleum reservoirs.
The pyrolysis of polyborazinylamine precursors leading to boron nitride(BN)ceramics has been studied by means of DTA-TG-GC,FTIR and XRD.The results show that the pyrolysis starts at 180℃ and the loss of 60% weight mainly occurs under 600℃.N2, NH3 and HCl are given off during pyrolysis and h-BN ceramics are obtained at 1600℃.
An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.
The reaction pyrolysis mechanism of polycarbosilane (PCS) precursor systems with active filler Al and inert filler SiC was investigated by TG-DTA, XRD and ELEM of the pyrolysis products at different temperatures under a flowing nitrogen stream. The results show that the pyrolysis of PCS began at about 400 ℃ and is basically completed at 800 ℃. Mass loss is caused due to the volatilization of small molecular. When PCS, especially SiC powders are contained, the nitridation temperature of Al decreases greatly with a much high conversion ratio from Al to aluminium nitride (AlN). Al powders were melting when the pyrolysis temperature increased up to 600 ℃, and reacted with the ambient SiC powders or the semi-pyrolysis products of PCS to form interphases, such as [Al a C b ] and , which reacted with nitrogen to produce AlN and SiC when the temperature further increases. The reaction is almost completed when the temperature increases up to 1 000 ℃.
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