Enhanced strength and ductility of Mg-Gd-Y-Zr alloys by secondary extrusion

The Mg-12Gd-3Y-0.6Zr(GW123,wt.%)alloy was prepared by cast,and thermo-mechanically treated by single and secondary hot extrusion techniques.The microstructure,texture and mechanical properties of the extruded alloy were investigated.The results show that in different treated conditions the microstructure is mainly composed ofα-Mg solid solution and second phases of Mg_(3)Y_(3)Gd_(2) and Mg_(5)(GdY)precipitates.The best mechanical properties are achieved in the secondary extruded alloy after ageing,with the ultimate tensile strength(UTS),tensile yield strength(TYS)and elongation(ɛ)being 446 MPa,350 MPa and 10.2%at room temperature.A weak texture aligned with〈101¯0〉||ED(extrusion direction)component and spread from〈101¯0〉to〈112¯0〉poles was obtained in secondary extrusion,which is caused by the occurrence of dynamic recrystallization(DRX)in shear bands for texture randomization.The fracture modes in extruded GW123 alloy are mixed pattern of transgranular and intergranular fracture,as well as cleavage fracture.The strengthening mechanisms were quantitatively analysed from the different aspects using the measured microstructural parameters.The grain boundaries and solid solution strengthening were the main contributors to the high tensile strength of the GW123 alloy.

Improved measurement of the reactor antineutrino flux and spectrum at Daya Bay

A new measurement of the reactor antineutrino flux and energy spectrum by the Daya Bay reactor neutrino experiment is reported. The antineutrinos were generated by six 2.9 GWth nuclear reactors and detected by eight antineutrino detectors deployed in two near(560 m and 600 m flux-weighted baselines) and one far(1640 m flux-weighted baseline) underground experimental halls. With 621 days of data, more than 1.2 million inverse beta decay(IBD) candidates were detected. The IBD yield in the eight detectors was measured, and the ratio of measured to predicted flux was found to be 0.946±0.020(0.992±0.021) for the Huber+Mueller(ILL+Vogel) model. A 2.9σ deviation was found in the measured IBD positron energy spectrum compared to the predictions. In particular, an excess of events in the region of 4–6 MeV was found in the measured spectrum, with a local significance of 4.4σ. A reactor antineutrino spectrum weighted by the IBD cross section is extracted for model-independent predictions.

3D-Stacked Multistage Inertial Microfluidic Chip for High-Throughput Enrichment of Circulating Tumor Cells

Whether for cancer diagnosis or single-cell analysis,it remains a major dhallenge to isolate the target sample cells from a large background cell for high-efficiency downstream detection and analysis in an integrated chip.Therefore,in this paper,we propose a 3D stacked multistage inertial microfluidic sorting chip for high-throughput enrichment of circulating tumor cells(CTCs)and convenient downstream analysis.In this chip,the first stage is a spiral channel with a trapezoidal cross-section,which has better separation performance than a spiral channel with a rectangular cross-section.The second and third stages adopt symmetrical square serpentine channels with different rectangular cross-section widths for further separation and enrichment of sample cells reducing the outlet flow rate for easier downstream detection and analysis.The multistage channel can separate 5 pum and 15 um particles with a separation efficiency of 92.37%and purity of 98.10%at a high inlet flow rate of 1.3 mL/min.Meanwhile,it can separate tumor cells(SW480,A549,and Caki-1)from massive red blood cells(RBCs)with a.separation efficiency of>80%,separation purity of>90%,and a concentration fold of~20.The proposed work is aimed at providing a high-throughput sample processing system that can be easily integrated with flowing sample detection methods for rapid CTC analysis.