The electrochemical performances of hydrogen- and oxygen-terminated nano-crystalline diamond film electrodes were investigated by cyclic voltammetry and AC impedance spectroscopy. In addition, the surface morphologies, phase structures, and chemical states of the two diamond films were analysed by scanning probe microscopy, Raman spectroscopy, and X-ray photoelectron spectroscopy, respectively. The results indicated that the potential window is narrower for the hydrogen-terminated nano-crystalline diamond film than for the oxygen-terminated one. The diamond film resistance and capacitance of oxygen-terminated diamond film are much larger than those of the hydrogen-terminated diamond film, and the polarization resistances and double-layer capacitance corresponding to oxygen-terminated diamond film are both one order of magnitude larger than those corresponding to the hydrogen-terminated diamond film. The electrochemical behaviours of the two diamond film electrodes are discussed.

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Piezoelectric materials have a piezoelectric effect that converts mechanical energy into electrical energy. In this paper, the blades of the rotating wind turbine are simplified as flexible beams fixed on the rotating wheels, and piezoelectric ceramics are added to the beams as sensors and actuators respectively to establish an analysis model of the vibration behavior of the piezoelectric sandwich rotating wind turbine blades. Based on Newton's second law, different accelerations are added to the rotating wheel to obtain the differential equation of a vibration variable coefficient. The fourth order Runge-Kutta method is used to solve variable coefficient differential equations. The hypothetical modal method is applied to solve the displacement of the free end of the flexible beam. A numerical simulation is also carried out to analyse the magnitude and change trend of the voltage output by adding piezoelectric materials at different angular velocities. The results show that the greater the rotational angular velocity, the greater the displacement of the free end of the flexible beam, and the greater the voltage due to the piezoelectric effect of the piezoelectric material. When the rotation angular velocity reaches a stable value, the displacement of the free end and the generated voltage will also reach a stable value.

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