Various Co-based SAPO-34 catalysts were prepared using different methods, including ion exchange (IE), incipientwetness impregnation (IWI), and solid-phase grinding (SPG), to correlate the chemical states of Co species with the C−H and C−C bond scissions in ethane dehydrogenation. The IE-prepared Co/ SAPO-34 led to stable, unreducible, and isolated exchanged Co sites anchored on the zeolite framework with a structure of −Al F − O−Co−O− and showed the highest selectivity to ethylene of close to 98% at 600 °C, which suggests that these Co sites favors suppressing the C−C bond scission in ethane. In comparison, the IWI-and SPG-prepared Co/SAPO-34 catalysts, especially for those with a high Co loading, inevitably give Co oxide clusters that are easily reduced into metallic Co. Together with catalytic results, characterizations, and DFT calculations, it is confirmed that the reduced Co clusters, especially for those outside SAPO-34 channels without the confinement effect, favor both C−H and C−C bond scission, boosting the conversion of ethane into CH 4 or/and coke; however, the ionic-state −Co−O− species can smoothly terminate the ethane dehydrogenation for the ethylene product due to relatively high energy barriers for both C−H and C−C bond scission, avoiding a deep dehydrogenation and C−C cracking. As expected, the unreducible −Co−O− sites are very stable in the title reaction without deanchoring from the zeolite framework in a 100 h cyclic test. This study not only demonstrates the stable −M δ+ −O δ− structure favorable for suppressing C−C bond scission but also highlights a catalyst-constructing strategy for Co-based and similar metal-based catalysts for dehydrogenation of other light alkanes.

In this paper, the output-feedback control problem of a vehicle active seat-suspension system is investigated. A novel optimal design approach for an output-feedback H ∞ controller is proposed. The main objective of the controller is to minimize the seat vertical acceleration to improve vehicle ride comfort. First, the human body and the seat are considered in the modeling of a vehicle active suspension system, which makes the model more precise. Other constraints, such as tire deflection, suspension deflection and actuator saturation, are also considered. Then the output-feedback control strategy is adopted since some state variables, such as body acceleration and body deflection, are unavailable. A concise and effective approach for an output-feedback H ∞ optimal control is presented. The desired controller is obtained by solving the corresponding linear matrix inequalities (LMIs) and by the calculation of equations proposed in this paper. Finally, a numerical example is presented to show the effectiveness and advantages of the proposed controller design approach.

In this paper, the static output-feedback control problem of 5 degrees of freedom (DOF) vehicle active suspension systems is investigated. A novel H ! optimal controller is designed for this system to improve simultaneously ride comfort and handling ability. The actuator saturation, suspension deflection and tire deflection are considered in the controller synthesis. To minimize the seat acceleration, taking into account the vehicle body vertical acceleration and pitch acceleration, a new method for designing and solving static output-feedback H ! optimal controllers is proposed. First of all, a 5 DOF halfvehicle active suspension including active seat system model is presented. Then a direct, easily solved and effective method for static output-feedback H ! optimal control is presented. The controller is obtained by solving linear matrix inequality optimization problem and direct computation of related matrices. Finally, a numerical example is presented. The simulation results show that the controller proposed can achieve better performance compared with state feedback H ! optimal controller and the validity of the design method is verified.

According to the characteristics of the tool hydraulic control system of the double cutters experimental pplatform, intelligent control methodology forecasted by fuzzy neural network is introduced into the control system. The two level control systems of fuzzy neural network predictive control and fuzzy control are designed. The fuzzy neural network predictive controller mainly completes the analysis and control of the speed and pressure in the tool hydraulic system. The speed control signal and pressure control signal from the first level are output to the fuzzy controller. Then, through logical reasoning, the control signal is output and the actuator is driven by the fuzzy controller to complete the control function of the tool system. In this paper, compared with the traditional PID control, the fuzzy neural network predictive control technology has better control accuracy, dynamic response performance and steady-state accuracy. The fuzzy neural network predictive control technology can be used to control the tool hydraulic system of Tunnel Boring Machine.

This paper presents the dynamic model of heavy-duty concrete spreader with liquid-solid rigid-flexible coupling by means of mathematical modeling and CAE cosimulation. The mathematical method of liquid-solid dynamic model of heavy-duty concrete spreader is described. Based on the liquid-solid coupling system, two degrees of freedom are added to change the model into a liquid-solid rigid-flexible coupling model, and the calculation process of the model is given in detail. The results show that, considering two flexible body factors, the solution scale is relatively large and the complexity of mathematical model derivation is increased. It is very difficult to establish a general dynamic equation which can be easily solved by computer. Therefore, this paper presents a new method of CAE cosimulation of liquid-solid rigid-flexible coupling. This method is divided into two parts: the computer simulation process of liquid-solid coupling and the computer simulation process of rigid-flexible coupling. First, the fluid-solid coupling is carried out by COMSOL software, and then the rigid-flexible coupling is carried out by HyperMesh software, Ansys software, and Adams software. This method can easily establish the dynamic model of the liquid-solid rigid-flexible coupling system, which provides a new idea for the simulation of heavy-duty concrete spreader. The simulation results can provide valuable insights into product design and structural optimization.