水口连滑在宣钢90t钢包上的应用

宣钢炼铁厂90t钢包采用LS70-150WT型滑动水口进行两次连滑,能够满足生产要求,加快了钢包周转,经济效益显著。

Freeze-thaw bond properties of new-old concrete

Using composite cubic specimens of new-old concrete,the bond splitting tensile strength and failure mechanism for the interface of new-old concrete in saturating state were explored when exposed to freeze-thaw cycling. Specimens were experienced for 0,25,50,75,100 and 125 freezing cycles. The roughness and adhesion agent including cement paste,cement mortar and cement paste with 10 percent of UEA expanding agent were also investigated. The test results indicate that the bond splitting tensile strength decreases with increased numbers of freezing-and-thawing cycles. The roughness and adhesion agent have different effects on the bond strength.

Paleo-fluvial sedimentation on the outer shelf of the East China Sea during the last glacial maximum

Evidence from lithology, foraminiferal assemblages, and high-resolution X-ray fluorescence scanning data of core SFK-1 indicates tidally influenced paleo-fluvial sedimentation during the last glacial maximum (LGM) on the outer shelf of the East China Sea. The paleo-fluvial deposits consist of river channel facies and estuarine incised-valley-filling facies. Different reflections on the seismic profile across core SFK-1 suggest that the river channels shifted and overlapped. River channel deposition formed early in the LGM when sea level fell and the estuary extended to the outer shelf. Channel sediments are yellowish- brown in color and rich in foraminifera and shell fragments owing to the strong tidal influence. Following the LGM, the paleo-river mouth retreated and regressive deposition of estuarine and incised-valley-filling facies with an erosion base occurred. The river channel facies and estuarine incised-valley-filling facies have clearly different sedimentary characteristics and provenances. The depositional environment of the paleo-river system on the wide shelf was reconstructed from the foraminiferal assemblages, CaCO3 content and Ca/Ti ratio. The main results of this study provide further substantial constraints on the recognition of late Quaternary stratigraphy and land-sea interactions on the ECS shelf.

Population structure and demographic history of the chukar partridge Alectoris chukar in China

Pleistocene climate fluctuations have shaped the patterns of genetic diversity observed in extant species. Although the effects of recent glacial cycles on genetic diversity have been well studied on species in Europe and North America, genetic legacy of species in the Pleistocene in north and northwest of China where glaciations was not synchronous with the ice sheet development in the Northern Hemisphere or or had little or no ice cover during the glaciations＇ period, remains poorly understood. Here we used phylogeographic methods to investigate the genetic structure and population history of the chukar partridge Alec- toris chukar in north and northwest China. A 1,152 - 1,154 bp portion of the mtDNA CR were sequenced for all 279 specimens and a total number of 91 haplotypes were defined by 113 variable sites. High levels of gene flow were found and gene flow esti- mates were greater than 1 for most population pairs in our study. The AMOVA analysis showed that 81% and 16% of the total genetic variability was found within populations and among populations within groups, respectively. The demographic history of chukar was examined using neutrality tests and mismatch distribution analyses and results indicated Late Pleistocene popula- tion expansion. Results revealed that most populations of ehukar experienced population expansion during 0.027 - 0.06 Ma. These results are at odds with the results found in Europe and North America, where population expansions occurred after Last Glacial Maximum （LGM, 0.023 to 0.018 Ma）. Our results are not consistent with the results from avian species of Tibetan Plateau, either, where species experienced population expansion following the retreat of the extensive glaciation period （0.5 to 0.175 Ma）