A Sensitive Ratiometric Fluorescent Sensor for Zinc(II) with High Selectivity

sensor

A review on source identification of dissolved sulfate in groundwater: Advances, problems and development trends

Effective identification of the sources and biogeochemical processes of dissolved sulfate in groundwater is an important prerequisite for ensuring drinking water safety and aquatic ecological security and is of significance to manage and protect groundwater resources. In this review, the sources of groundwater sulfate and the typical range of δ34S and δ18O isotope from different sulfate sources are summarized by reviewing the literature; the identification of sulfate sources and S biogeochemical cycles by δ34S and δ18O isotope in sulfate is reviewed, and the existing problems and development trends are proposed. The source apportionment of groundwater sulfate sources has gone through the processes of hydrochemistry analysis→δ34S isotope→dual isotope→qualitative identification of multiple isotopes and tracers→quantitative evaluation. Due to the differences in sulfur and oxygen isotopes and the biogeochemical transformation processes in a specific region, there is still a larger uncertainty in the determination of groundwater sulfate sources.It is proposed to arrange the sampling points for collecting pollution sources and groundwater samples on the framework of groundwater flow systems and land use distributions and to analyze the hydrochemical components and the sulfur and oxygen isotope values of sulfate and other complementary tracer isotope values and/or concentrations in a specific area. The sources and their contributions of groundwater sulfate are analyzed using multidisciplinary and multi-methods based on the full integration of hydrogeochemistry, seepage field, land use and other information in a study area for the scientific implementation of groundwater resource protection and pollution prevention

Fracture behavior of low cycle fatigue and dwell fatigue of Ti6242 titanium alloy under high load

As one kind of near alpha titanium alloys with excellent mechanical properties, Ti6242 alloy always shows the“dwell fatigue”characteristic, which is similar to other near α or α+β titanium alloys, especially at near room temperature. In this study, the low cycle fatigue and dwell fatigue tests under high load were designed according to the law of dwell fatigue sensitivity rising with the increase of test load. Combining with microstructure observation, mechanical property characterization and failure fracture analysis, the relationship between the microstructure and fracture behavior under high load low cycle fatigue and dwell fatigue tests was analyzed systematically. By summarizing the characteristics of failure fracture under room temperature tensile, high load low cycle fatigue test and high load dwell fatigue test, also comparing the dwell fatigue sensitivity of the Ti6242 alloy in this study with other Ti6242 alloys and other titanium alloys under different loading conditions, it is proved that increasing the fatigue load is a feasible way to characterize the dwell fatigue sensitivity of Ti6242 alloy

Carbon nanotube (CNT) metal composites exhibit greatly reduced radiation damage

© 2020 Acta Materialia Inc. Radiation damage of structural materials leads to mechanical property degradation, eventually inducing failure. Secondary-phase dispersoids or other defect sinks are often added to materials to boost their radiation resistance. We demonstrate that a metal composite made by adding 1D carbon nanotubes (CNTs) to aluminum (Al) exhibits superior radiation resistance. In situ ion irradiation with transmission electron microscopy (TEM) and atomistic simulations together reveal the mechanisms of rapid defect migration to CNTs, facilitating defect recombination and enhancing radiation tolerance. The origin of this effect is an evolving stress gradient in the Al matrix resulting from CNT transformation under irradiation, and the stability of resulting carbides. Extreme value statistics of large defect behavior in our simulations highlight the role of CNTs in reducing accumulated damage. This approach to controlling defect migration represents a promising opportunity to enhance the radiation resistance of nuclear materials without detrimental effects

Supplementary document for Design of wavelength division multiplexing devices based on tunable edge states of valley photonic crystals - 6342614.pdf

Design of wavelength division multiplexing devices based on tunable edge states of valley photonic crystal

Supplementary document for Design of wavelength division multiplexing devices based on tunable edge states of valley photonic crystals - 6357139.pdf

Design of wavelength division multiplexing devices based on tunable edge states of valley photonic crystal