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Semiconductor photocatalytic technology is widely used in the degradation of antibiotic pollutants due to its easy operation, low energy consumption, and no secondary pollution. In this study, ZnO/TiO2 composite photocatalysts with the different sturcture and the different content were constructed using layered double hydroxide as precursor. The structure and physicochemical properties of the photocatalysts were characterized by the different characterization technologyies, such as XRD, SEM, FT-IR, LRS, UV–vis DRS, N2 adsorption–desorption isotherm, XPS, UPS, EIS, and so on. The photocatalytic degradation performance and mechanism for tetracycline hydrochloride were studied. The results show that the light response performances of the as-prepared samples are improved by a calcination process. The surface active sites are increased and the transport and separation efficiency of photogenerated electrons and holes are improved. Among them, ZnO/TiO2-200 has the fastest degradation rate and the best catalytic activity, and its maximum apparent rate constant is 0.9576 × 10–3 L·mg−1·min−1. The analysis of photocatalytic mechanism and energy band structure shows that the main active substance of the system is ·O2−, and the photocatalytic degradation process follows the type II heterojunction photocatalytic reaction mechanism. This study provides ideas for the design and construction of high-efficiency photocatalytic composites, and provides a reference for the photocatalytic degradation of other organic pollutants. [ABSTRACT FROM AUTHOR]

Optimal shape control is important in fuselage assembly processes. To achieve high precision assembly, shape adjustment is necessary for fuselages with initial shape deviations. The state-of-the-art methods accomplish this goal by using actuators whose forces are derived from a model based on the mechanical properties of the designed fuselage. This has a significant limitation: they do not consider the model mismatch due to mechanical property changes induced by the shape deviation of an individual incoming fuselage. The model mismatch will result in control performance deterioration. To improve the performance, the shape control model needs to be updated based on the online feedback information from the fuselage shape adjustment. However, due to the large size of the fuselage surface, highly accurate inline measurements are expensive or even infeasible to obtain in practice. To resolve those issues, this article proposes a Sparse sensor Placement-based Adaptive Control methodology. In this method, the model is updated based on the sparse sensor measurement of the response signal. The reconstruction performance under a minor model mismatch is quantified theoretically. Its performance has been evaluated based on real data of a half-to-half fuselage assembly process, and the proposed method improves the control performance with acceptable sensing effort. [ABSTRACT FROM AUTHOR]

The research on the formation factors of rock burst is one of the main research directions of rock mechanics in recent years, which is helpful to solve the problem of rock burst accidents. So, in this study, the calculation method of energy released during rock burst is first obtained by using different medium models, and then, the formation factors of rock bursts are obtained by comparing the calculation energy with the actual accident energy. The method of energy calculation utilizes the difference between elastoplastic and pure elastic models to innovatively quantify the specific values of energy released before and after the occurrence of the rock burst. It is considered that the stress and plastic zone state before the occurrence of rock burst have an important influence on the occurrence of the accident and are one of the formation factors, while the deviatoric stress field and butterfly-shaped plastic zone create conditions for greater energy release. In addition, the trigger stress constitutes another formation factor. The plastic zone state before rock failure is verified by the experimental test; the location distribution shape of acoustic emission (AE) events during the later stage of compression failure is approximately the same as theoretical result. The results also preliminarily indicated the fractal characteristics of acoustic emission events distribution before sample failure. The study obtained the formative factors of rock burst accident, which provides a new ideas and references for the research on the formation of rock bursts. [ABSTRACT FROM AUTHOR]