Residual current device (RCD), the critical equipment to protect the safety of electrical users, are known to experience performance degrade over time during their use lifetime. Therefore, in order to promptly replace the RCD before failure, it is very important to predict its lifetime. In order to predict the remaining life of the RCD, a constant‐stress accelerated degradation test (CSADT) and a combination prediction model are proposed. First, the CSADT is conducted with temperature as the acceleration stress and the residual operating current as degradation characteristic. Then, based on the prediction result of pseudo failure life, a combination model of Wiener process and GM (1, 1) model is given. Finally, the remaining life of the RCD under normal use environment is extrapolated. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Phenylacetylene capped silicon nanoparticles (Phenyl-SiNPs) have attracted interest as a novel thermoelectric material. Here we report a combined muon spectroscopic (µSR) and computational study of this material in solution to investigate microscopic electronic structure in this system. For comparison, the model molecular compound tetrakis (2-phenylethynyl) silane has also been investigated. µSR measurements have shown that the muon isotropic hyperfine coupling constant, Aµ, which depends on spin density at the muon, is greatly reduced for the Phenyl-SiNPs system when compared to the model compound. Results have also demonstrated that the temperature dependence of Aµ for the Phenyl-SiNPs is of opposite sign and proportionally larger when compared to the model compound. Ab initio DFT methods have allowed us to determine the muon addition site in the model compound, while a wider computational study using both DFTB+ and CASTEP offers a qualitative explanation for the reduced coupling seen in the Phenyl-SiNPs system and also the contrasting temperature dependence of Aµ for the two materials. Calculations suggest an increase in the density of electronic states at the energy level of the highest occupied molecular state for the Phenyl-SiNPs, even in the presence of an organic cap, suggesting a mechanism for enhanced electron transport in this system when compared to the tetrakis model compound.

No abstract

No abstract

Silicon has been proved to be one of the most promising anode materials for the next generation of lithium-ion battery. For the application in batteries, Si anode should have high capacity and must be industrially scalable. In this study, we have designed and synthesised a hollow structure to meet these requirements. All the processes are carried out without special equipment. The Si nanoparticles that are commercially available are used as the core sealed inside TiO2 shell, with rationally designed void space between the particles and shell. The Si@TiO2 are characterised using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and scanning electron microscope (SEM). The optimised hollow structured silicon nanoparticles, when used as anode in lithium-ion battery, exhibit a high reversible specific capacity over 600 mAhg-1. This excellent electrochemical property of the nanoparticles can be attributed to their optimised phase and unique hollow nanostructure.