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Friction torque disturbance affects the tracking performance of electromechanical actuator servo system, bringing position and speed tracking errors, and even may leading to instability of the servo system. Aiming at the problem of poor tracking performance of electromechanical actuator servo system under friction torque disturbance, a FOANN friction compensation algorithm is proposed to estimate and compensate the friction torque. Firstly, base on LuGre friction model, a electromechanical actuator model is established, and the unmeasured state variable in the LuGre model is estimated by radial basis function neural network. Secondly, a FOANN controller is designed, and the stability of corresponding closed-loop system is proved by Lyapunov stability theory. Finally, through simulation and experimental platform, the dynamic performance of FOANN is compared with those of traditional PD and MRAC. The simulation and experimental results show that, with the proposed FOANN friction torque compensation algorithm, the tracking errors of both position and velocity of electromechanical actuator servo system are greatly reduced. FOANN algorithm can effectively estimate and compensate friction torque, reduce the impact of friction disturbance and enhance the dynamic performance of the servo system.

The CO2-water-rock interaction is the core issue of CO2 geological sequestration. The injection of CO2 disrupts the chemical balance of rock-formation water， and the changes in the chemical properties of formation water， primary mineral dissolution， and secondary mineral precipitation will lead to changes in the physical properties of reservoir and caprock， such as porosity， wettability， and mechanical properties and thus directly affect the CO2 injection capacity， sequestration efficiency， and sequestration security and stability. Based on the mechanism of CO2-water-rock interaction， this paper systematically expounds on the research progress of the effects of CO2-water-rock interaction on porosity， permeability， wettability， and mechanical properties of formation rocks. The results show that the change in rock porosity and permeability caused by CO2-water-rock interaction is closely related to its initial porosity and permeability characteristics and mineral composition， and the change of rock porosity and permeability characteristics directly affects the injection capacity and sequestration potential of the reservoir and the sealing capacity of the caprock. The change in wettability is related to the initial hydrophilic and oil-philic characteristics. The CO2-water-rock interaction usually weakens the water wettability of the hydrophilic rocks and enhances that of the oil-philic rocks， thus affecting the microscopic distribution and seepage characteristics of the multiphase fluids in the pores of the rocks. Due to the dissolution of cement and the formation of dissolution holes， the CO2-water-rock interaction will cause rock damage， and the mechanical parameters such as compressive strength， tensile strength， and elastic modulus will decrease. To a certain extent， the security of sequestration is affected. Under the setting of carbon neutrality， the CO2-water-rock interaction and rock physical property response under the scenarios of micro-nano-scale pore， deep microbial mediation， impure CO2 or industrial tail gas injection， and full sequestration cycle still need to be further studied.

Mesoporous manganese oxide (meso-MnO y) and its supported Co, Pt, and Pt x Co catalysts are prepared via the KIT-6-templating and PVA-protected reduction routes, respectively. The excellent catalytic activity of 0.70 wt% Pt 2.42 Co/meso-MnO y is associated with its highly dispersed Pt 2.42 Co alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Pt 2.42 Co NPs and meso-MnO y. • Pt x Co/meso-MnO y is prepared via the polyvinyl alcohol-protected reduction route. • Pt x Co alloy is formed in each of the Pt x Co/meso-MnO y samples. • 0.70 wt% Pt 2.42 Co/meso-MnO y performs the best for methanol combustion. • Pt x Co alloy, O ads content, reducibility, and metal-support interaction govern activity. The KIT-6-templating and polyvinyl alcohol-protected NaBH 4 reduction methods were adopted to prepare the mesoporous manganese oxide (meso-MnO y) and its supported Co, Pt, and Pt x Co catalysts, respectively. Numerous techniques were used to characterize the physicochemical properties of the materials. Catalytic performance of the samples was evaluated for methanol combustion. All of the samples possessed a three-dimensionally ordered mesoporous structure and a surface area of 94–110 m2/g. The Co, Pt, and Pt x Co nanoparticles (NPs) with an average size of 2.2–3.0 nm were uniformly dispersed on the surface of meso-MnO y. The 0.70 wt% Pt 2.42 Co/meso-MnO y sample performed the best: the T 50% and T 90% (temperatures required for achieving methanol conversions of 50 and 90%, respectively) were 50 and 86 °C at a space velocity of 80,000 mL/(g h). The partial deactivation of the 0.70Pt 2.42 Co/meso-MnO y sample due to water vapor or carbon dioxide introduction was reversible. It is concluded that the excellent catalytic activity of 0.70 wt% Pt 2.42 Co/meso-MnO y was associated with its highly dispersed Pt 2.42 Co alloy NPs, high adsorbed oxygen species concentration, good low-temperature reducibility, and strong interaction between Pt 2.42 Co alloy NPs and meso-MnO y. [ABSTRACT FROM AUTHOR]