No abstract

In order to provide specific references and suggestions for the design and operation of underground pumping stations, in this paper, an experimental model of an underground pumping station, including 4 pumps and 2 pump intakes (primary and secondary), was obtained through similitude of fluid mechanics. The phase diagrams of various vortices, in terms of different dimensionless numbers are presented, which can reveal their appearance and evolution process. Three specific cases with different vortex flows were analyzed. The experiment results may provide a reference for the current design guidelines for underground pumping stations.

No abstract

Er3+‐doped sodium lanthanum aluminosilicate glasses with compositions of (90−x)(0.7SiO2·0.3Al2O3)·xNa2O·8.2La2O3· 0.6Er2O3·0.2Yb2O3·1Sb2O3 (in mol%) (x= 12, 20, 24, 40, 60 mol%) were prepared and their spectroscopic properties were investigated. Judd–Ofelt analysis was used to calculate spectroscopic properties of all glasses. The Judd–Ofelt intensity parameter Ωt (t= 2, 4, 6) decreases with increasing Na2O. Ω2 decreases rapidly with increasing Na2O while Ω4 and Ω6 decrease slowly. Both the fluorescent lifetime and the radiative transition rate increase with increasing Na2O. Fluorescence spectra of the 4I13/2 to 4I15/2 transition have been measured and the change with Na2O content is discussed. It is found that the full width at half‐maximum decreases with increasing Na2O.