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The damping coefficient and dynamical load characteristics are sensitive to the dynamic response of the underground powerhouse. In this paper, based on results of dynamic identification of the underground powerhouse of a pumpedstorage power plant previously made, the immune algorithm is used together with the ANSYS Code and the highfrequency water pressure pulsation during a routine operation and the damping ratio are identified and studied with observed data. This will be useful for generating a precise numerical model and studying the hydropower station.

Volcanic ash is a major threat to aviation safety. The softening/melting temperatures of volcanic ash lie far below typical aero‐engine operating temperatures. Thus, molten ash can accelerate the failure of thermal barrier coatings (TBCs). Here, inspired by natural superhydrophobic surfaces (e.g., the lotus leaf), a molten‐volcanic‐ash‐phobic TBC, which provides a large possibility to eliminate molten ash issues of TBCs, is developed. A hierarchically structured surface is first prepared on a (Gd0.9Yb0.1)2Zr2O7 (GYbZ) pellet by ultrafast laser direct writing technology, aiming to confirm the feasibility of the biomimetic microstructure to repel molten volcanic ash wetting. Then biomimetic‐structured GYbZ TBCs are successfully fabricated using plasma spray physical vapor deposition, which reveals “silicate” phobicity at high temperatures. The exciting molten‐volcanic‐ash‐phobic attribute of the designed surfaces is attributed to the lotus‐leaf‐like dual‐scale microstructure, emulating in particular the existence of nanoparticles. These findings may be an important step toward the development of next‐generation aviation engines with greatly reduced vulnerability to environmental siliceous debris.

Copper strips experience severe corrosion when rolled with an oil-in-water (O/W) emulsions lubricant. The effects of rolling reduction on the pitting corrosion behavior and surface microstructure of Cu strips were studied in detail using electrochemical measurements and electron back scattered diffraction (EBSD) analysis. It was found that the corrosion current densities of the rolled Cu strips increased with accumulated reduction, which also lowered the pitting potentials and weakened their corrosion resistances. Therefore, the corrosive tendency of Cu strips under different rolling reductions (ε) followed the order of ε0% < ε20.7% < ε50.6% < ε77.3%. The Cu surface easily reacted with chlorine, sulfur, and carbon components from O/W emulsions to generate pitting corrosion. Under the interactive effect of pitting corrosion and stress corrosion, pits expanded along the rolling direction. The aggregation of anions in surface defects, such as dislocations, metastable pits, and microcracks, further accelerated the pitting corrosion of the surface.

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