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In this study, a fluorocarbon chain was grafted on the surface of the alumina insulator through the molecule self-assembly of perfluorododecyl trichlorosilane to enhance the vacuum surface flashover voltage. A hydrocarbon chain with the same molecular structure, devoid of fluorine element, was also grafted through the self-assembly of dodecyl trichlorosilane to enable comparison. The surface state examination of the self-assembled alumina insulators shows that both the molecules are attached to the alumina surface. The arrangement of the molecules on the surface is regular. Surface property tests reveal that the fluorocarbon chain endows the surface of alumina with a lower secondary electron emission yield and a lower gas adsorption volume than the hydrocarbon chain. Correspondingly, the surface flashover voltage of the fluorocarbon chain grafted insulator is higher than that of the hydrocarbon chain. This implies that the surface flashover voltage can be improved through surface fluorination, which converts hydrocarbon bonds to fluorocarbon bonds. The study demonstrates this possibility at the molecule level. [ABSTRACT FROM AUTHOR]

This paper utilizes a coupled chemomechanical model that integrates chemical reactions, diffusion, and mechanical deformation to describe the high-temperature interfacial reactions and stress evolution within an enamel coating/Ni-based super-alloy system. Through finite element simulation, we conduct a comprehensive analysis of multiple reactions and processes at the interface. Experimental characterization of the concentration distribution of various elements is employed to verify the accuracy of the proposed chemomechanical model. Additionally, the simulation reveals that the interface region experiences compressive circumferential stress, which can potentially lead to interfacial failure due to buckling. On the other hand, the enamel coating undergoes tensile circumferential stress, resulting in the formation of vertical surface cracks. These findings hold practical implications for the development of advanced coatings with enhanced durability and performance. Future research can further optimize coating design and enhance the reliability of high-temperature applications based on these results. [ABSTRACT FROM AUTHOR]

With the increase in environment protection requirements and the development of pulse-power technology, environmentally friendly antiferroelectric materials with superior energy storage performance have received increasing attention. The present work proposes a combinatorial optimization technique to optimize the energy storage capabilities of NaNbO3-based ceramics, that is, the AFE P phase can be stabilized and anti-parallel polar nanoregions (APNRs) are proposed to reduce the electric field-induced remnant polarization response (decrease Pr) by introducing Bi(Zn0.5Hf0.5)O3 into the NaNbO3 ceramic, then further use of rolling to increase the breakdown strength (enhance Eb). Consequently, a large Wrec of 5.82 J cm−3 and an outstanding η of 86.7% at 531 kV cm−1 are obtained by a repeated rolling process, together with excellent frequency (1–200 Hz) and cycling (1–106) stability. Here, the results show that the combinatorial optimization technique is effective in developing the energy storage performance of lead-free ceramics. [ABSTRACT FROM AUTHOR]

A machine learning (ML) model, optimized by the Particle Swarm Optimization (PSO) algorithm, was developed in this study to predict the shear slip load of adhesive/bolt-reinforced corroded steel plates. An extensive database comprising 490 experimental or numerical specimens was initially employed to train the ML models. Eight ML algorithms (RF, AdaBoost, XGBoost, GBT, SVR, kNN, LightGBM, and CatBoost) were utilized for shear slip load prediction, with their hyperparameters set to default values. Subsequently, the PSO algorithm was employed to optimize the hyperparameters of the above ML algorithms. Finally, performance metrics, error analysis, and score analysis were employed to evaluate the prediction capabilities of the optimized ML models, identifying PSO-GBT as the optimal predictive model. A user-friendly graphical user interface (GUI) was also developed to facilitate engineers using the PSO-GBT model developed in this study to predict the shear slip load of adhesive/bolt-reinforced corroded steel plates. [ABSTRACT FROM AUTHOR]

In the process of human social development, the coupling and coordinated development of ecological function (EF), production function (PF), and living function (LF) are of great significance for sustainable development. In this study, an improved coupling coordination degree model (CCDM) is used to discover the coordination conflict between EF and a human settlement environment. The main work performed in this study is as follows: (1) A more objective weight value that can avoid analysis errors caused by a subjective judgment weight value is obtained. (2) A constitutive model of EF, PF, and LF is constructed, and then resilience indicators that reflect the burden of human activities in EF are proposed. (3) We find that, during the urbanization of Ya'an city from 2014 to 2018, the degree of coupling (DOC) between EF, PF, and LF is high, but the coupling coordination degree (CCD) between the three values is low; specifically, the DOC between EF and the other two values shows the biggest decline. (4) Finally, the resilience of EF is used to explain the decrease in coordination between EF, PF, and LF, while also explaining the obvious problem of a decrease in CCD between EF and the other two values. In this study, the method for calculating the DOC and COD is optimized, and then, a theoretical model for analyzing the ecological functions bearing the pressure of human activities from qualitative and quantitative perspectives is proposed. The research results can provide an analytical framework, path, and method for the coordinated development of "PF–LF–EF" in other regions. [ABSTRACT FROM AUTHOR]

Comparative measurements with high-pressure spark gaps (gas pressure: 0.2–0.9 MPa nitrogen, gap spacing 5 mm) are presented, one with a regular Bruce-profile polished graphite cathode (diameter 25 mm, thickness 8 mm) and the other with a microarray graphite cathode of equal dimensions. By microstructuring, a V-type graphite microarray is created by purpose-developed laser treatment of a plane graphite electrode. The microarray graphite cathode brings more initial plasma and then produces more initial electrons. It is beneficial for electron emission, which improves the stability of the switch breakdown. The experimental results are achieved at a gas pressure of 0.9 MPa and a 200-kV voltage pulse applied to the switch. With these parameters, the mean breakdown voltage is 91.7 kV, the minimum is 91.4 kV, and the mean relative standard deviation in breakdown voltage of the first 100 shots is 0.4%. Compared to a plane graphite cathode, the mean breakdown voltage is about 10% lower, and the mean relative standard deviation is reduced by more than 90%. The main result can be stated that microarray graphite cathodes are a suitable choice as electrodes for low-jitter high-pressure spark gaps. [ABSTRACT FROM AUTHOR]

Continuous variable measurement-device-independent quantum key distribution (CV-MDI-QKD) removes all known or unknown side-channel attacks on detectors. However, it is difficult to fully implement assumptions in the security demonstration model, which leads to potential security vulnerabilities inevitably existing in the practical system. In this paper, we explore the impact of imbalanced modulation at transmitters on the security of the CV-MDI-QKD system mainly using a coherent state and squeezed state under symmetric and asymmetric distances. Assuming two different modulation topologies of senders, we propose a generalized theoretical scheme and evaluate the key parameter achievable of the protocol with the mechanism of imbalanced modulation. The presented results show that imbalanced modulation can achieve a relatively nonlinearly higher secret key rate and transmission distances than the previous protocol which is the balanced modulation variance used by transmitters. The advantage of imbalanced modulation is demonstrated for the system key parameter estimation using numerical simulation under different situations. In addition, the consequences indicate the importance of imbalanced modulation on the performance of CV-MDI-QKD protocol and provide a theoretical framework for experimental implementation as well as the optimal modulated mode. [ABSTRACT FROM AUTHOR]