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Elucidating the mechanical forces between two solid surfaces immersed in a communal liquid environment is crucial for understanding and controlling adhesion, friction, and electrochemistry in many technologies. Although traditional models can adequately describe long-range mechanical forces, they require substantial modifications in the nanometric region where electronic effects become important. A hybrid quantum–classical model is employed herein to investigate the separation-dependent disjoining pressure between two metal surfaces immersed in an electrolyte solution under potential control. We find that the pressure between surfaces transits from a long-range electrostatic interaction, attractive or repulsive depending on the charging conditions of surfaces, to a strong short-range van der Waals attraction and then an even strong Pauli repulsion due to the redistribution of electrons. The underlying mechanism of the transition, especially the attractive–repulsive one in the short-range region, is elucidated. This work contributes to the understanding of electrotunable friction and lubrication in a liquid environment. [ABSTRACT FROM AUTHOR]

Polyurea is widely used in marine anti-corrosion engineering because it has the physical advantages of high tensile strength, strong adhesion, excellent waterproof and anti-corrosion performance as well as mature construction technology. In this paper, the origin, characteristics and development direction of polyurea coating technology were first introduced, and then the applications of polyurea coating in the fields of concrete protection and metal protection in marine atmospheric environment and seawater environment in recent years were summarized, respectively. Aiming at the problems of coating performance degradation and failure caused by complex environmental factors such as temperature, corrosive medium erosion and collision during service, the research progress of new polyurea coatings was discussed, including the research on improving the performance of coatings such as corrosion resistance, wetting and hardness with organic and inorganic nanoparticles as fillers, and the research on new polyurea microcapsule coatings that could respond intelligently and repair microcracks independently, and the research on the processing and preparation technology of new self-healing materials such as electrospinning. Finally, the shortcomings and challenges of the current research on polyurea coating were pointed out, and the future research trend of polyurea coating in marine environment was prospected.

In the electrolyte containing Nd2O3 particles with different concentrations, the micro - arc oxidation technology was used to prepare the coatings on the surface of 2A12 aluminum alloy. The effects of Nd2O3 particles with different concentrations on the hardness, thickness and adhesion strength between the micro - arc oxidation coating and the substrate were studied, which provided a theoretical basis for the preparation of the coatings with good performance on the surface of 2A12 aluminum alloy by micro - arc oxidation. In addition, scanning electron microscope (SEM), X - ray diffraction (XRD) and X - ray photoelectron spectroscopy (XPS) were used to analyze the cross section morphology and phase composition of the coatings. TT - 230 eddy current thickness tester, HVS - 1000 digital Vickers hardness tester and MFT - 4000 multi - functional material surface performance tester were used to test the coating thickness, hardness, and adhesion strength, respectively. Results showed that the coatings were mainly composed of α - Al2O3, γ - Al2O3 and SiO2 phases. With the increase of Nd2O3 particle concentration, the hardness, thickness, and adhesion strength between the coating and the substrate performed a trend of first increasing and then decreasing. Moreover, when Nd2O3 particle concentration was 0.3 g/L, the micro hardness, thickness, and adhesion strength between the coating and the substrate reached the maximum value of 576.38 HV, 8.17 μm and 16.7 N. In summary, adding Nd2O3 was an effective method to enhance the properties of 2A12 aluminum alloy micro - arc oxidation coating, and the optimal concentration was 0.3 g/L.

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This study explored the relationship between lean management, carbon inventory, and carbon reduction, along with the main factors affecting factory carbon inventory and carbon reduction, and proposed a set of carbon emission reduction strategies based on green value stream mapping. An electroplating factory and its production line in Taiwan was selected. Fourteen carbon inventory records, three work circle meetings, and green value flowcharts were utilized to collect and analyze data. Furthermore, this study applied the DMAIC framework and TRIZ to solve the issue of carbon emissions. The key factor affecting factory carbon inventory and carbon reduction was found to be electricity waste, which could be reduced through energy-saving methods. After analyzing the green value stream mapping, effective carbon emission reduction can be implemented in the manufacturing process. The company was found to gradually progress towards carbon reduction after investigating seven major green wastes. This study confirms that lean management can help organizations achieve their carbon emission reduction goals and is valuable in improving the organization's environmental performance and competitiveness. [ABSTRACT FROM AUTHOR]

Skyrmions, a stable topological vectorial textures characteristic with skyrmionic number, hold promise for advanced applications in information storage and transmission. While the dynamic motion control of skyrmions has been realized with various techniques in magnetics and optics, the manipulation of acoustic skyrmion has not been done. Here, the propagation and control of acoustic skyrmion along a chain of metastructures are shown. In coupled acoustic resonators made with Archimedes spiral channel, the skyrmion hybridization is found giving rise to bonding and antibonding skyrmionic modes. Furthermore, it is experimentally observed that the skyrmionic mode of acoustic velocity field distribution can be robustly transferred covering a long distance and almost no distortion of the skyrmion textures in a chain of metastructures, even if a structure defect is introduced in the travel path. The proposed localized acoustic skyrmionic mode coupling and propagating is expected in future applications for manipulating acoustic information storage and transfer. [ABSTRACT FROM AUTHOR]