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Oscillating parameters are key factors that affect sidewall penetration and restrain incomplete fusion in vertical oscillating arc all-position narrow-gap gas metal arc welding (NG-GMAW). In this regard, the back-propagation neural network (BPNN) optimized by gradient optimization algorithms is applied to describe the relationship between the oscillating parameters and the welding specifications. The welding current and speed were selected as the input parameters and the oscillating width and frequency as the output parameters. Experimental results show that the prediction accuracy reaches 86%. The performance tests show that the optimized parameters can be used to guide automatic welding in engineering applications. This article provides a foundation for the establishment of processing models for all-position NG-GMAW with a vertical oscillating arc. [ABSTRACT FROM AUTHOR]

This paper investigates the issue of energy-to-peak control for continuous-time switched systems. A generalized switching signal, known as persistent dwell-time switching, is considered. Two different strategies for state-feedback controller design are proposed, using distinct Lyapunov functions and a few decoupling techniques. The critical distinction between these two strategies lies in their temporal characteristics: one is time-independent, while the other is quasi-time-dependent. Compared to the former, the latter has the potential to be less conservative. The validity of the proposed design strategies is demonstrated through an example. [ABSTRACT FROM AUTHOR]

This paper considers event-triggered H ∞ control for Lurie systems with switching exponential time-varying gains. An extended switched event-triggered mechanism (ESETM) is proposed by incorporating the state information at the latest triggered instant into the threshold function. A piecewise H ∞ control law, which includes switching exponential time-varying gains, is introduced. With the aid of a coordinate transformation and a piecewise Lyapunov function, a control approach that ensures the exponential stability of the Lurie system without interference is developed. On this basis, the desired event-triggered H ∞ controller is designed for the Lurie system with interference. Finally, a flexible joint manipulator model is used to validate the superiority of the proposed ESETM-based H ∞ controller design. [ABSTRACT FROM AUTHOR]

In this work, hierarchical Cu2ZnSnS4 microspheres were synthesized via a hydrothermal method with the utilization of polyethylene glycol as surfactant and characterized in detail. The polyethylene glycol modified Cu2ZnSnS4 microspheres presented a mesoporous structure with optical bandgap of 1.47 eV and specific surface area of 15.6 m2/g, while the Cu2ZnSnS4 microspheres without polyethylene glycol modification exhibited a hierarchical sphere-like morphology with optical bandgap about 1.49 eV and specific surface area of 29.6 m2/g. The photoluminescence and electrochemical measurements confirmed that polyethylene glycol modified Cu2ZnSnS4 possesses higher charge separation efficiency than Cu2ZnSnS4 without polyethylene glycol modification. The sonocatalytic activity of as-prepared Cu2ZnSnS4 was evaluated by the decolorization of methylene blue. The results displayed that the polyethylene glycol modified Cu2ZnSnS4 microspheres lead to rapid removal of methylene blue. Over 95.0% methylene blue was snonocatalytic decolorized by polyethylene glycol modified Cu2ZnSnS4 microspheres after 20 min ultrasound irradiation, while only about 82.1% of methylene blue was decolorized over Cu2ZnSnS4 without polyethylene glycol modification. The effect of radical scavengers on methylene blue decolorization process was evaluated and clarified that the sonogenerated holes and hydroxyl radicals are the main active oxidative species in sonocatalytic process. Sonocatalytic activity remained at 87.6% after three recycles. Sonocatalytic process using hierarchical CZTS microspheres for MB decolorization. [ABSTRACT FROM AUTHOR]

Bones are extremely dynamic organs that continually develop and remodel. This process involves changes in numerous gene expressions. hBMSC cells can promote osteogenic differentiation. The purpose of this study was to elucidate the mechanism by which ASCL1 promotes osteogenic differentiation in hBMSC cells while decreasing glycolysis. hBMSCs were induced to differentiate into osteoblasts. The ASCL1 expression level during hBMSC osteogenic differentiation was measured by RT‒qPCR, Western blotting, and immunofluorescence. The differentiation level of osteoblasts was observed after staining with ALP and alizarin red. ChIP-qPCR were used to determine the relationship between ASCL1 and CD47, and the expression of glycolysis-related proteins was detected. Overexpression of ASCL1 was used to determine its impact on osteogenic differentiation. si-USP8 was used to verify the ubiquitination of ASCL1-mediated CD47/AKT pathway's impact on hBMSC glycolysis and osteogenic differentiation. The results showed that the expression of ASCL1 was upregulated after the induction of osteogenic differentiation in hBMSCs. From a functional perspective, knocking down USP8 can promote the ubiquitination of ASCL1, while the osteogenic differentiation ability of hBMSCs was improved after the overexpression of ASCL1, indicating that ASCL1 can promote the osteogenic differentiation of hBMSCs. In addition, USP8 regulates the ubiquitination level of ASCL1 and mediates CD47 transcriptional regulation of the AKT pathway to increase the glycolysis level of hBMSCs and cell osteogenic differentiation. USP8 ubiquitination regulates the level of ASCL1. In addition, ubiquitination of ASCL1 mediates CD47 transcription to activate the AKT signaling pathway and increase hBMSC glycolysis to promote osteogenic differentiation. [ABSTRACT FROM AUTHOR]

The issue of H ∞ stabilization for delayed memristive neural networks with dynamic quantization is considered. The aim is to design a quantized sampled-data controller guaranteeing that the closed-loop system is globally asymptotically stable with a prescribed H ∞ disturbance attenuation level. By means of set-valued maps and the differential inclusion theory, the network under consideration is transformed into a dynamic model subject to time-dependent bounded uncertainty. Then, two different time-dependent two-sided loop functionals are constructed for the non-necessarily and necessarily differential time delay situations, respectively. Two sufficient conditions on the stability and H ∞ performance are derived via using these constructed functionals and a few inequality techniques. On the foundation of these conditions, co-designs of the needed feedback gain and dynamic quantization parameter are presented. Finally, three examples are provided to verify the applicability of the quantized sampled-data controller design methods. [ABSTRACT FROM AUTHOR]

Large-scale rotating detonation experiments with a 500 mm outer diameter combustor are carried out in this study. The experiment used aviation kerosene (RP-3) as fuel and hot air as oxidant. Detonation is successfully initiated between the equivalent ratio of 0.85 and 1.20. The engine works steadily for 2 s and 3 s. The detonation wave modes are two-wave collision. The average speed of detonation wave is between 920 m/s and 980 m/s. The detonation wave velocity increases with the increase in equivalence ratio, and when the equivalence ratio exceeds 1.0, the increasing trend of detonation wave slows down. Through sampling and analysis of detonation gas, it is found that the uneven distribution of fuel supply pressure in large-scale rotating detonation experiment results in inconsistent local equivalent ratio and uneven combustion. The complete combustion rate based on carbon atoms is used to evaluate the combustion completeness of detonation. With the increase in equivalent ratio, the combustion changes from deflagration to detonation, and the detonation combustion completeness gets better. The combustion completeness of detonation wave is the best near the appropriate chemical equivalent ratio. Once the equivalent ratio exceeds 1.0, then oil-rich combustion occurs and the strength of the detonation wave becomes weaker. [ABSTRACT FROM AUTHOR]