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The growth of Cu2O crystal planes was be controlled by adding surfactant to the NaCl solution in this manuscript. The structure and composition of the synthesized Cu2O particles were characterized by X‑ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FESEM), and specific surface area test method (BET). The photocatalytic activities were evaluated by degrading methyl orange (MO) solution under magnetic stirring. The results shown that the synthesized Cu2O particle was spherical self-assembly structure when the surfactant was CTAB, and behaved higher degradation performance. Under dark conditions, the adsorption efficiency of 100 mg L–1 MO solution reached 67.08% in the first 1 min by 0.33 g L–1 CTAB-Cu2O, and after 15 min, the adsorption degradation efficiency of MO had reached 99.17%. The maximum adsorption capacity of CTAB-Cu2O was 297.28 mg g–1. The adsorption kinetics obeyed pseudo-second-order kinetics and followed the Freundlich isotherm. [ABSTRACT FROM AUTHOR]

In this paper, the problem of open-switch faults of a voltage source inverter system is investigated. A new fault diagnosis method based on an observer and an adaptive threshold is proposed. This method only needs to utilize the signals existing in a system without the need for extra hardware circuits. First, an observer is designed on a model of a three-phase voltage source inverter system to estimate currents. Then, an adaptive threshold is designed on fault residuals, dynamics of the currents and variations of the system operating state. Moreover, the dead time and switching delay time are also included in the threshold to consider practical applications. Furthermore, to achieve on-line real-time diagnosis and to improve the reliability of the proposed method, the averages of the current residuals in a current fundamental period are defined as diagnostic variables. Finally, the reliability and effectiveness of the proposed method are verified by simulation and experiment results. [ABSTRACT FROM AUTHOR]