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Inconel 617 nickel-based superalloy with 3 mm wall thickness was welded by laser beam using two different heat input welding parameters. The microstructure of the welded joint was observed by optical microscope and scanning electron microscope, and the mechanical properties of the welded joint at room temperature (25℃) and high temperature (900℃) were tested. The results show that the laser welding heat input has a significant effect on the microstructure and mechanical properties of Inconel 617 welded joints. The front width of the laser weld obtained by high heat input (200 J/mm) process parameters is 3.88 mm. The grain size in the middle of the weld fusion zone is coarse, and the grain orientation is disordered. The secondary dendrite arm spacing in the middle of the weld is large (6.71 μm). The carbide particle size between the dendrites is coarse, and the solidification microsegregation of Mo, Cr alloy elements is serious. The width of heat affected zone is about 0.29 mm. The eutectic structure of γ+carbide is formed in the grain boundary and grain interior. This is because during the heating process of the welding, the spherical carbide particles and the surrounding austenite in the heat-affected zone liquefy and the eutectic structure is formed during the solidification process after welding. The front width of the laser weld obtained by low heat input (90 J/mm) process parameters is 2.28 mm, the grains inside the weld are columnar which is formed by epitaxial growth along the fusion line and directional solidification along the heat flow direction. The secondary dendrite arm spacing in the middle of the weld is small (2.26 μm), the carbide particles between dendrites are small, and the width of heat affected zone is about 0.15 mm. The tensile strength test at room temperature (25℃) shows that the welded joints obtained under high heat input fracture from the middle of the weld, and the tensile strength and elongation decrease, which is caused by the segregation of solid solution elements in the weld. The welded joints obtained under low heat input fracture from the base metal. At high temperature (900℃), all samples fracture from the base metal, which is due to the weakening of the grain boundary of the base metal at high temperatures.

The advent of smart grid technologies has brought about a paradigm shift in the management and operation of distribution networks, allowing for intricate system information to be encapsulated within semantic network models. These models, while robust, are not immune to faults within their knowledge entities, which can arise from a myriad of issues, potentially leading to verification failures and operational disruptions. Addressing this critical vulnerability, our research delves into the development of a novel fault detection methodology specifically tailored for the knowledge entity variables of semantic networks in distribution networks. In our approach, we first construct a state space equation that models the behavior of knowledge entity variables in the presence of faults. This foundational framework enables us to apply an unknown input observer strategy to effectively detect anomalies within the system. To bolster the fault identification process, we introduce the innovative use of a siamese network, a neural network architecture which is proficient in differentiating between similar datasets. Through simulation scenarios, we demonstrate the efficacy of our proposed fault detection method. [ABSTRACT FROM AUTHOR]

In this paper, we report on the Ag nanoparticle-containing hybrid poly(N-isopropylacrylamide-co-acrylic acid) (PNIPAM-co-PAA) microgels with pH- and thermoresponsive metal-enhanced fluorescence (MEF). The hybrid microgels were prepared by in situ reducing Ag salts to Ag nanoparticles in the PNIPAM-co-PAA microgels. According to the interaction distance-dependent nature of MEF effects, we can realize a controllable MEF effect by adjusting the average interaction distance between fluorophores and Ag nanoparticles due to the good stimuli-responsive swelling-shrinking behavior of the hybrid microgels. The results show that MEF effect can be well tuned in the pH region 2-12 as well as the temperature region of 20-50 °C. By this method, an enhanced fluorescence detection can possibly be manipulated by adjusting external stimuli such as pH and temperature.