Synthesis of mordenite by solvent-free method and its application in the dimethyl ether carbonylation reaction

Mordenite with different Si/Al ratios were synthesized by solvent-free method and used for dimethyl ether(DME)carbonylation reaction.The influence of Si/Al ratio in the feedstock on the structure,porosity and acid sites were systematically investigated.The characterization results showed that with the increase of Si/Al ratio in the feedstock,part of silicon species fail to enter the skeleton and the specific surface area and pore volume of the samples decreased.The amount of weak acid and medium strong acid decreased alongside with the increasing Si/Al ratio,and the amount of strong acid slightly increased.The Al atoms preferentially enter the strong acid sites in the 8 member ring(MR)channel during the crystallization process.The high Si/Al ratio sample had more acid sites located in the 8 MR channel,leading to more active sites for carbonylation reaction and higher catalytic performance.Appropriately increasing the Si/Al ratio was beneficial for the improvement of carbonylation reaction activity over the mordenite(MOR)catalyst.

A pin-moment model of flexoelectric actuators

Owning to the unique property of generating pure bending deformation, flexoelectric curvature actuators hold promise for various future applications, especially in the micro and nano scales. This paper proposes three models to predict the deformation of one-dimensional isotropic beams under the excitation of flexoelectric curvature actuators, including the pin-moment model, the pin-force-moment model and Euler-Bernoulli model. The pin-moment model represents the simplest model by only considering the moments interaction between the actuators and the beam at both ends, while the pin-force-moment model incorporate both the force and moment interactions. Comparison between the results of these two models with the Euler-Bernoulli model results indicates that the pin-moment model overestimates the curvature of the beam under a small thickness ratio of the beam and actuator, whereas a good agreement is reached between the pin-force-moment model results with that obtained by the Euler-Bernoulli-model. The accuracy of the pin-force-moment model and the Euler-Bernoulli model was further verified by a finite-element analysis. Therefore the pin-force-moment model could provide a simple and accurate method to characterise the performance of flexoelectric curvature actuators, enlightening the implementation of them for numerous future applications.