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Abstract Rational design of bimetallic alloy is an effective way to improve the electrocatalytic activity and stability of Mo-based cathode for ampere-level hydrogen evolution. However, it is still critical to realise desirable syntheses due to the wide reduction potentials between different metal elements and uncontrollable nucleation processes. Herein, we propose a rapid Joule heating method to effectively load RuMo alloy onto MoOx matrix. As-prepared catalyst exhibits excellent stability (2000 h @ 1000 mA cm−2) and ultralow overpotential (9 mV, 18 mV and 15 mV in 1 M KOH, 1 M PBS, 0.5 M H2SO4 solution, respectively) at 10 mA cm−2. Based on first-principle simulations and operando measurements, the impressive electrocatalytic stability and activity are investigated. And the role of rapid Joule heating method is highlighted and discussed in details. This study showcases rapid Joule heating as a feasible strategy to construct highly efficient alloy-based electrocatalysts.

The optical time domain reflectometer (OTDR) curve features of communication fibers exhibit subtle differences among their normal, subhealthy, and faulty operating states, making it challenging for existing machine learning-based fault diagnosis algorithms to extract these minute features. In addition, the OTDR curve field fault data are scarce, and data-driven deep neural network that needs a lot of data training cannot meet the requirements. In response to this issue, this paper proposes a communication fiber state diagnosis model based on fuzzy clustering and an improved ResNet. First, the pretrained residual network (ResNet) is modified by removing the classification layer and retaining the feature extraction layers. A global average pooling (GAP) layer is designed as a replacement for the fully connected layer. Second, fuzzy clustering, instead of the softmax classification layer, is employed in ResNet for its characteristic of requiring no subsequent data training. The improved model requires only a small amount of sample training to optimize the parameters of the GAP layer, thereby accommodating state diagnosis in scenarios with limited data availability. During the diagnosis process, the OTDR curves are input into the network, resulting in 512 features outputted in the GAP layer. These features are used to construct a feature vector matrix, and a dynamic clustering graph is formed using fuzzy clustering to realize the fiber state diagnosis. Through on-site data detection and validation, it has been demonstrated that the improved ResNet can effectively identify the full cycle of fiber states.

Abstract The goal of this review is to present a detailed and comprehensive description of the published work from the past decade regarding methods of improved material, geometric design, and additional functions in root canal files. The main improved methods of files and the most common technologies were further addressed, underlining their advantages and main limitations. Online databases (the Derwent Innovations Index) were consulted on this topic. Published work from 2010 to 2022 was collected and analyzed the relevant papers were chosen for inclusion in this review. The patent map classified the latest phase of the root canal files based on the analysis of the number of patents. The performance of the root canal files, such as materials. Directly affects the quality of the root canal therapy. We provided a thorough review of advances in the field of root canal files. In particular, three categories of improved methods were examined and compared, including material-based methods, geometry-based methods, and those based on additional functions. To understand this state of the art of different improved methods of root canal files, we conducted a literature analysis and a series of comparisons between different methods. The features and limitations of each method of root canal files were further discussed. Finally, we identified promising research directions in advancing the methods for the improved performance of root canal files. There is no perfect technology for all material/geometric design/additional functions, capable alone of fulfilling all the specificity and necessities of every patient. Although it is very promising, the material of the files remains understudied, and further work is required to make material science a pervasive technology in root canal therapy, and contribute to endodontic and periapical diseases by assisting in the subsequent development of root canal files.

The traditional precast concrete column-to-column connections are widely used in the prefabricated concrete frame structures in China. However, many studies on the column-to-column joints have demonstrated their complex forms and poor construction efficiency. To overcome these shortcomings, a new type column–column connection with steel plate hoop and bolts was designed and proposed. In order to reveal the seismic performance of this new type connection, four precast concrete columns and two cast-in-situ columns were tested by cyclic lateral loading. They were compared and analyzed from the aspects of test phenomenon, failure mode, load–displacement relationship, strength, and stiffness degradation. The results showed that the prefabricated columns with this new type connection had the same seismic performance as the cast-in-place columns. Additionally, the strain curves of longitudinal reinforcement, stirrups, and steel plate hoops were presented, and the force transmission mode of this novel connection was analyzed. The results indicated that the innovative connection had reliable force transmission mode, which can provide reference for the application of prefabricated frame structure in the earthquake area.

Stereo garage technology can effectively alleviate the problem of parking difficulties, but the safety problems of its actuators, via which the core of stereo parking function can be realized, seriously affect its promotion and further development. In this paper, a two degrees of freedom (2-DOF) parallel lifting actuator for a stereo parking robot is designed by researching the type synthesis of the mechanism based on the screw theory. The limb constrained triangle method, the flexibility of limb constrained triangle, and the failure probability are proposed to determine the final configuration of the parallel lifting actuator. Then, this paper completes the dimensional optimization of the parallel lifting actuator based on the multi-motion performance indexes and kinematic analysis, which improves the safety and stability of the actuator. Finally, this paper verifies the validity of the parallel lifting actuator by establishing a parallel lifting actuator verification model system. By verifying the dynamic characteristics of the model mobile platform under different load conditions, it is proven that the kinematic stability of the mobile platform decreases with the increase of load mass under load conditions. Additionally, through practical application experiment, it is proven that the parallel lifting mechanism can effectively alleviate the parking difficulty problem.

As the development of building industrialization and housing industrialization is speeding up in China, the application of precast concrete structure has been the research focus. The connection of prefabricated components is one of the key technologies in prefabricated concrete structure. So, a new type of column–column connection with steel plate hoop and bolts is proposed in this paper to promote the application of precast concrete structure. In order to reveal the flexural behavior and force transfer mechanism about this new type connection, six precast concrete beams and one integral casting beam were tested by the three-point bending under loading and unloading cycle. The comparative analysis is made between the new type connection and traditional integral cast-in-place member from the aspects of test phenomenon, failure mode, and load-deflection relationship. The analysis results show that the new type connection has the same bending bearing capacity as the integral casting member. Based on the analysis of the load-strain relationship of longitudinal reinforcement, bolts, and steel plate hoop, the moment transmission mechanism and theoretical calculation formula of the new type connection are proposed, and the theoretical calculation results are consistent with the experimental results.

Backfill mining is the most environmentally friendly mining method at present, which can effectively control the surface subsidence, improve the recovery rate, and has good social and economic benefits. The purpose of this study is to solve the environmental problems caused by solid waste, combined with the rich geographical advantages of aeolian sand in the Yushenfu mining area of China. The rheological properties of the aeolian sand-fly ash-based filling slurry with different fly ash content are studied by experiments, and the strength development law of the filling body under different age and fly ash content are studied from the macroscopic and microscopic points of view. The rheological experiments showed that the increase of the amount of fly ash has a significant effect on the thixotropy, plastic viscosity, and yield stress of the filling slurry. Additionally, rheological properties of aeolian sand-fly ash-based filling slurry conform to the Bingham model. With the increase of the amount of fly ash, the performance of the filling slurry has been significantly improved. Uniaxial test and scanning electron microscope observation showed that the influence of fly ash on the strength of the filling body was mainly reflected in the late stage of maintenance, but was not obvious in the middle stage. Fly ash particles mainly bear the role of “water reduction” and a physical filling effect, which makes the filling slurry thicker and the internal structure more closely spaced. The volcanic ash reaction of fly ash is lagging behind the hydration reaction of cement; the secondary product of the delayed reaction is filled in the pores of cement hydrates, which can greatly reduce the porosity of the backfill body and increase the later strength of the backfill body. It provides a guarantee for the safe replacement of coal pillars in the working face.