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To mitigate the decrease in mechanical performance of Sn58Bi/Cu solder joints resulting from electromigration-induced damage. The CeO2 nanoparticles were incorporated into Sn58Bi solder by a melt-casting method, and their effects on the microstructure and properties of Sn58Bi/Cu solder joints under electromigration were investigated. The study results demonstrate that the addition of 0.125 ~ 0.5 wt% CeO2 nanoparticles refines the eutectic microstructure of Sn58Bi solder alloy. At an addition amount of 0.5 wt%, the composite solder alloy exhibits the maximum tensile strength of 68.9 MPa, which is 37% higher than that of the base solder. CeO2 nanoparticle-reinforced Sn58Bi solder can achieve excellent solderbility with Cu substrates and the joints can significantly inhibit the growth of the anodic Bi-rich layer, which is responsible for electromigration. With the extension of current stressing time, Bi-rich and Sn-rich layer are respectively formed on the anode and cathode in the joints. The intermetallic compound (IMC) layer grows asymmetrically, transitioning from a fan-shaped morphology to a flattened structure at the anode and to a thickened mountain-like morphology at the cathode. Adding the CeO2 nanoparticles helps to mitigate the decrease in mechanical performance caused by electromigration damage during current application to some extent. Over the current stressing period of 288 ~ 480 h, the fracture position shifts from the anodic IMC/Bi-rich interface to the cathodic Sn-rich/IMC interface. The fracture mechanism transitions from a brittle fracture characterized by plate-like cleavage to a ductile–brittle mixed fracture with fine dimples and cleavage. [ABSTRACT FROM AUTHOR]

As a non-invasive body fluid, urine pH is one of the important biomarkers for diseases such as the kidneys. Therefore, rapid and accurate detection of urine pH is of great clinical significance. A novel fluorescent probe (SPPH-Cl) was developed based on Brooker’s merocyanine skeleton for pH detection. The pKa of SPPH-Cl was adjusted to 6.55 using a phenolic hydroxyl ortho substitution strategy, therefore, the fluorescence response range of SPPH-Cl to pH covers the urine physiological pH range (4.6-8.0). SPPH-Cl has excellent water solubility, stable recoverability, wide anti-interference capability, and sensitive reactions to pH fluctuations in pure aqueous solutions. SPPH-Cl has succeeded in applying to monitor the pH of volunteer urine samples based on a standard curve established in artificially simulated urine, and the detection results have accuracy comparable to pH meters. Therefore, this work provided a powerful molecule tool for detecting pH in urine samples. [ABSTRACT FROM AUTHOR]