Three Devonian magmatic rocks have been identified from the mid‐western part of the Yanshan Thrust‐and‐Fold Belt (YTFB). Here, we present new geochronological, Sr–Nd–Hf isotopic, and whole‐rock chemical data. Our new LA‐ICP‐MS U–Pb dating recognized syenite plutons of ca. 385 Ma, which include Laogongying, Shicheng, and Qiaomaiyu, respectively, around the Yunmeng Mountain in the Miyun–Huairou area of Beijing. Rocks from three plutons are characterized by low SiO2 and high alkali contents, especially high K2O, and they show syenite and foid syenite compositions. They display slight–middle light REE enrichment, no negative or positive Eu anomalies, strong depletion in Rb, Th, U, Nb, Ta, P, Zr, Hf, and Ti, enrichment in Ba, K, and Sr, low contents of Y and Yb, and high Sr/Y ratios. They have a relatively narrow range of isotopic compositions with initial 87Sr/86Sr ratios from 0.708203 to 0.710477, εNd(t) values from −12.26 to −13.28, and εHf(t) values from −19.92 to −17.96. This study shows the Middle Devonian intrusions were produced by fractional crystallization of a parental magma, which was derived by interaction between mantle‐derived alkaline magmas of a type I‐enriched mantle and pre‐existing continental crust. Tectonic background was likely emplaced in a back‐arc extension environment related to southward subduction of the Palaeo‐Asian oceanic plate or during the cessation of the subduction. Feldspar geothermometer and aluminium‐in‐hornblende barometry studies of the Middle Devonian plutons yielded emplacement temperature of ~700°C and pressure of ~6.5 kbar, indicating the emplacement depths of about 24 km. Combined with previous geobarometry results on the Middle Devonian plutons within the Inner Mongolia Palaeo‐uplift (IMPU) on the northern margin of the NCC, the strong uplift and exhumation the IMPU were identified during Middle Devonian to Late Triassic times. The exhumation was more than 4–5 km than those of the IMPU, resulting in widely absent of Palaeozoic strata within the YTFB.

The influence of sediment media on the blade pressure and cavitation of a tubular turbine was investigated in this study. The Zwart–Geber–Belamri cavitation model and the shear stress transport k–w turbulence model were applied to numerically simulate and experimentally validate the full flow path of the tubular turbine under combined conditions for sediment particle sizes of 0.01 and 0.05 mm and concentrations of 1%, 1.5%, and 2%. The results show that the pressure of the blade increases with the sediment concentration. Cavitation mainly occurs between the blade shroud and the leading edge. The higher the sediment concentration, the lower the vapor volume fraction at the same sediment particle size. The presence of sediments inhibits further cavitation development, and the inhibition effect is significant. At the same concentration, the larger the particle size of the sediment, the lower the vapor volume fraction. Thus, the increase in the particle size inhibits cavitation, but the inhibition effect is not significant.

This paper combines new palaeomagnetic studies, palaeontological dating, and sedimentary analyses to propose a modified stratigraphic classification scheme in the northwestern Songliao Basin, which is of great significance for stratigraphic correlation, sedimentation analysis, basinal subsidence, and oil and gas exploration. New palaeontological and palaeomagnetic evidence redefined a group of semi‐consolidated lacustrine strata, buried beneath the Quaternary Yaluhe Formation on the Western Slope of the Songliao Basin, as Late Cretaceous, not the Middle Pleistocene. The chronostratigraphic framework re‐evaluates its stratigraphic age as late Coniacian to early Campanian (Late Cretaceous), between 83 and 85 Ma. Sedimentation research from 17 boreholes on the Western Slope of the Songliao Basin displays that the semi‐consolidated strata successively experienced lacustrine and delta facies deposits. Comparison of this new stratigraphy with the Late Cretaceous sequences on the adjacent Central Depression of the Songliao Basin reveals significant variations in lithology and palynological assemblages. Three new palynological assemblages are also reported from the Late Cretaceous sequences of the Songliao Basin.