Gaskets are compressed in proton exchange membrane fuel cells (PEMFCs) to keep fuel, oxidant and coolant within their respective regions and are very important for sealing and maintaining electrochemical performance of fuel cells during their long-term operation. It has been proved that the gas leakage caused by the failure of the gaskets following long-term operation is one of the main reasons for PEMFC performance degradation. In this work, degradation of silicone rubbers, the potential gasket materials for PEMFCs, were investigated in the simulated PEMFC environment solution, weak acid solution, de-ionized water and air, respectively, under alternating temperature cycling from −20 °C to 90 °C. The changes in hardness, weight, chemical properties, mechanical behavior and surface morphology of the samples of silicone rubbers were studied after a certain number of temperature cycles. The results show that with the increase in temperature cycles, the hardness of the samples increases and the weight of the samples decreases gradually. Scanning electron microscopy reveals that cracks and caves constantly appear on the surface of the samples. Attenuated total reflection Fourier transform infrared spectra (ATR-FTIR) results demonstrate that the surface chemistry changes via de-crosslinking and chain scission in the backbone due to the exposure of samples to the environments over time under alternating temperature cycles.

A cocoon-like α-Fe₂O₃ nanocomposite with a novel carbon-coated structure was synthesized via a simple one-step hydrothermal self-assembly method and employed as supercapacitor electrode material. It was observed from electrochemical measurements that the obtained α-Fe₂O₃@C electrode showed a good specific capacitance (406.9 Fg⁻¹ at 0.5 Ag⁻¹) and excellent cycling stability, with 90.7% specific capacitance retained after 2000 cycles at high current density of 10 Ag⁻¹. These impressive results, presented here, demonstrated that α-Fe₂O₃@C could be a promising alternative material for application in high energy density storage.

This paper researches the problem that different thicknesses of silt of earthquake response and the differently distributed layered sediment with certain thicknesses for the seismic response of concrete dam. In this paper, there are layered silt layers of different thicknesses, and it is divided into three different forms of layered silt distributed based on the pressure wave equation of saturated porous fluid-solid two-phase medium. Under the conditions of both the same and the different physical parameter distribution of each distribution form of each layer, the magnitude of influence of silt on the response of concrete dam is determined. The analysis shows that the impact from the same physical properties with different forms of distrubition on seismic response is not significant, but the different distrubution forms have a larger impact on seismic response of the dam.