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Acoustic injection is one of the most dangerous ways of causing micro-electro&ndash, mechanical systems (MEMS) failures. In this paper, the failure mechanism of acoustic injection on the microprocessor unit 6050 (MPU6050) accelerometer is investigated by both experiment and simulation. A testing system was built to analyze the performance of the MPU6050 accelerometer under acoustic injection. A MEMS disassembly method was adopted and a MATLAB program was developed to establish the geometric model of MPU6050. Subsequently, a finite element model of MPU6050 was established. Then, the acoustic impacts on the sensor layer of MPU6050 were studied by acoustic&ndash, solid coupling simulations. The effects of sound frequencies, pressures and directions were analyzed. Simulation results are well agreed with the experiments which indicate that MPU6050 is most likely to fail under the sounds of 11,566 Hz. The failure mechanism of MPU6050 under acoustic injection is the relative shift of the capacitor flats caused by acoustic&ndash, solid resonance that make the sensor detect false signal and output error data. The stress is focused on the center linkage. MPU6050 can be reliable when the sound pressure is lower than 100 dB.

Three-dimensional (3D) nanometal scaffolds have gained considerable attention recently because of their promising application in high-performance supercapacitors compared with plain metal foils. Here, a highly oriented nickel (Ni) nanowire array (NNA) film was prepared via a simple magnetic-field-driven aqueous solution deposition process and then used as the electrode scaffold for the vapor-phase polymerization of 3,4-ethylenedioxythiophene (EDOT). Benefiting from the unique 3D open porous structure of the NNA that provided a highly conductive and oriented backbone for facile electron transfer and fast ion diffusion, the as-obtained poly(3,4-ethylenedioxythiophene) (PEDOT) exhibited an ultra-long cycle life (95.7% retention of specific capacitance after 20 000 charge/discharge cycles at 5 A/g) and superior capacitive performance. Furthermore, two electrodes were fabricated into an aqueous symmetric supercapacitor, which delivered a high energy density (30.38 Wh/kg at 529.49 W/kg) and superior long-term cycle ability (13.8% loss of capacity after 20 000 cycles). Based on these results, the vapor-phase polymerization of EDOT on metal nanowire array current collectors has great potential for use in supercapacitors with enhanced performance. Published version

Transparent conducting electrodes (TCEs) are an essential component for modern opto-electronic devices such as solar cells, organic light emitting diodes (OLEDs), liquid crystal displays (LCDs), and touch screen panels. However, traditional indium tin oxide (ITO) cannot meet the demand for the next generation highly flexible TCEs, and thus many novel alternative materials and technologies are blooming, such as super-aligned carbon nanotube, graphenes, conducting polymer and metal nanowire and so on. Among them, silver nanowires (Ag NWs) have been considered as one of the most promising technologies for TCEs, featured with superior electrical and optical properties. However, there are still two major challenges for Ag NWs-based TCEs technology to overcome. One is the poor mechanical interconnection between the Ag NWs conducting networks and transparent substrate, the other is the high contact resistance of the junctions among Ag NWs. Here we report a novel two-step electrostatic spraying process to fabricate Ag NWs TCEs composite with selectively coated conductive polymer, i.e. poly 3,4-ethylenedioxythiophene: polystyrenesulfonate (PEDOT:PSS). Additionally, we applied plasma treatment to the materials between two-step electrostatic spraying process, which rendered sintering of junctions between the Ag NWs at room temperature, and thus increasing the conductivity of the TCEs by at least three orders of magnitude. Results showed that by adjusting the electrostatic spraying process parameters, selective deposition can be achieved, i.e. the conductive polymer could tightly bound to the Ag NWs network. As compared to an even distribution of the coating layer in the whole area, selective coating rendered the negligible loss of transmittance (0.2% at most) and excellent adhesion to the substrate. Moreover, the composited TCEs exhibited 85.3% mean optical transmittance and 35.8 Ω/sq sheet resistance. Based on our results, we believe that this technology can be used for roll-to-roll preparation of silver nanowires (Ag NWs)-based TCEs.