Search

In order to ensure the straightening quality of spindle rod, reduce the labor intensity of workers and improve the working environment of workers, the causes of straightness error and deformation of spindle rod after hot rolling forming, longitudinal cutting forming, heat treatment and manual straightening were analyzed. The method of straightening the spindle rod with the automatic loading and unloading device of the manipulator on the thread rolling machine was adopted. With the method, the spindle rod was placed on the support plate between the two straightening rollers, and the moving roller moved forward, straightened, retreated and returned to the original position along the radial direction, with the spindle rod repeatedly bent and deformed along the axial direction through the spiral groove of the roller to achieve the purpose of straightening. At the same time, the structural characteristics and dimensions of the straightening roller and the support plate were introduced. The experimental results show that the spindle rod is straightened on the thread rolling machine after rough grinding, and the qualified rate is more than 90%; and the rod output reaches 3 000, which creates conditions for intelligent manufacturing of spindle rod.

It is a challenge to develop low-cost, efficient, and stable multi-functional electrocatalysts for the oxygen evolution reaction (OER), overall water splitting (OWS), oxygen reduction reaction (ORR), and zinc–air batteries (ZABs). To address such issues, for the first time, we rationally design and facilely construct iron-single-atom-coupled Fe3C on P-, F-, N-triply doped carbon nanotubes (FeSAs-PFN-CNTs). Herein, the modulation of the Fe atom coordination environment, low loading of Fe3C nanoparticles, and inclusion of heteroatom-doped CNTs facilitated ample proton-feeding and charge-transfer processes. As a result, the FeSAs-PFN-CNT catalyst delivers fast electrokinetics, exhibiting efficient OER (an overpotential (η10) of 310 mV with 24 h stability), admirable OWS anode (325 mV (η10) with 10 h stability), excellent ORR (an half-wave potential (E1/2) of 0.88 V with 6 h stability), and outstanding ZAB (an open-circuit voltage of 1.49 V, high specific capacity of 781 mA h gZn−1 (93.5% of the theoretical capacity of 835 mA h gZn−1), and ultrahigh power density of 241 mW cm−2) performances, which is superior to those of benchmark electrocatalysts. In this regard, this work provides an excellent scalable multifunctional catalyst for the commercialization of low-cost, efficient, and stable electrocatalysts for application in oxygen catalysis and Zn–air batteries. [ABSTRACT FROM AUTHOR]

Replacing platinum-based electrocatalysts with iron single-atom catalysts (Fe–N4–C) for the oxygen reduction reaction (ORR) remains challenging due to the symmetric electronic structure of atomically dispersed Fe–N4 sites and sluggish kinetics. To address this issue, we introduce Cu–Nx sites and graphene-encapsulated core–shell Fe–Cu nanoalloy (FeCu@G) particles into the Fe–Nx site surroundings through the self-assembly and pyrolysis of a metal–organic framework (MOF). This strategy leverages synergistic interactions with the associated species to modify the uniform electronic structure of Fe single-atom sites, thereby enhancing oxygen-adsorption/desorption kinetics. Density functional theory (DFT) calculations reveal that the incorporation of Cu–Nx sites and FeCu@G nanoalloy particles significantly alters the electronic structure of Fe–Nx sites, leading to improved ORR activity. Consequently, the optimized FeCu-DSAs@CNT, comprising dual single-atom sites (DSAs: Fe–Nx and Cu–Nx) and FeCu@G nanoalloy within MOF-derived nitrogen-doped carbon nanotubes (CNTs), exhibits a significantly improved half-wave potential (E1/2 = 0.91 V) and feasible ORR kinetics (Tafel slope = 48.15 mV dec−1), surpassing the Pt/C benchmark (E1/2 = 0.847 V and Tafel slope = 56.76 mV dec−1). Notably, FeCu-DSAs@CNT shows a 58 mV more positive E1/2 compared to monometallic Fe–SAs@CNT, attributed to synergistic interactions with Cu species. Moreover, it demonstrates excellent power density, specific capacity, and cycling stability in a lab-made zinc–air battery, outpacing the Pt/C-battery. This study addresses gaps in understanding Fe–Nx site interactions with associated species, providing valuable insights for the advancement of Fe–Nx–C electrocatalysts. [ABSTRACT FROM AUTHOR]

Efforts to enhance refrigeration efficiency and environmental friendliness are underway, focusing on the electrocaloric effect (ECE) as an alternative to traditional compression methods. Maintaining a substantial adiabatic temperature change (ΔT) across a broad temperature span (Tspan) induced by ECE is a significant challenge in achieving efficient, zero-emission ferroelectric refrigeration. This study introduces a stacked composite ceramic (SCC) with broad dielectric peaks, achieved by stacking ceramics with a specific ferroelectric–paraelectric phase transition. The interlayer synergies optimize between layers and amplify polarization changes due to flip domains and lattice distortion, enhancing ECE properties. Notably, SCC exhibits a substantial ΔTmax of 1.198 K and a wide Tspan of 64 °C at 50 kV cm−1, surpassing the cumulative properties of individual components. The study proposes an effective composite design strategy for developing high-performance electrothermal materials with exceptional ECE properties for practical refrigeration applications. [ABSTRACT FROM AUTHOR]

The occurrence of landslide hazards significantly induces changes in slope surface displacement. This study conducts an in-depth analysis of the multifractal characteristics and displacement prediction of highway slope surface displacement sequences. Utilizing automated monitoring devices, data are collected to analyze the deformation patterns of the slope surface layer. Specifically, the multifractal detrended fluctuation analysis (MF-DFA) method is employed to examine the multifractal features of the monitoring data for slope surface displacement. Additionally, the Mann–Kendall (M-K) method is combined to construct the α indicator and f (α) indicator criteria, which provide early warnings for slope stability. Furthermore, the long short-term memory (LSTM) model is optimized using the particle swarm optimization (PSO) algorithm to enhance the prediction of slope surface displacement. The results indicate that the slope displacement monitoring data exhibit a distinct fractal sequence characterized by h (q) , with values decreasing as the fluctuation function q decreases. Through this study, the slope landslide warning classification has been determined to be Level III. Moreover, the PSO-LSTM model demonstrates superior prediction accuracy and stability in slope displacement forecasting, achieving a root mean square error (RMSE) of 0.72 and a coefficient of determination (R2) of 91%. Finally, a joint response synthesis of the slope landslide warning levels and slope displacement predictions resulted in conclusions. Subsequent surface displacements of the slope are likely to stabilize, indicating the need for routine monitoring and inspection of the site. [ABSTRACT FROM AUTHOR]

The urgent demand for stable and highly efficient bifunctional electrocatalysts for the oxygen reduction/evolution reactions (ORR/OER) is pivotal in advancing energy conversion and storage technologies. Herein, we introduce a metal–organic framework (MOF)-derived bifunctional electrocatalyst Fe3Co-NC@900, featuring synergistically coupled dual single-atom sites (Fe/Co–Nx) and core–shell Co3Fe7@C nanoparticles. Leveraging the synergistic interactions of Fe–Nx sites with associated Co–Nx sites and core–shell nanoparticles within the MOF-derived nitrogen-doped mesoporous sheets and nanotubes, Fe3Co-NC@900 demonstrates outstanding ORR and OER performance, outpacing the Fe-NC@900 catalyst fabricated without Co incorporation. Specifically, it demonstrates superior ORR performance with a higher half-wave potential (E1/2) of 0.88 V and a small Tafel slope of 62.1 mV dec−1, surpassing the Pt/C benchmark (E1/2 of 0.82 V) and Fe-NC@900 (E1/2 of 0.788 V). Additionally, it demonstrates noteworthy OER performance, requiring a 1.572 V overpotential at 10 mA cm−2 current density, resulting in a significant bifunctional activity with a potential gap (ΔE) of 0.692 V, surpassing the Pt/C + Ir/C combination (ΔE = 0.748 V). Moreover, serving as a bifunctional air electrode, Fe3Co-NC@900 exhibits excellent performance in lab-made Zn–air batteries, with outstanding open circuit voltage, specific capacity, and cycling stability (>650 cycles), outpacing the Pt/C + Ir/C-based battery. [ABSTRACT FROM AUTHOR]

To better analyze the fluctuation characteristics and development law of tunnel deformation data, multifractal theory is applied to tunnel deformation analysis. That is, the multifractal detrended fluctuation analysis (MF-DFA) model is first utilized to carry out the multifractal characterization of tunnel deformation data. Further, Mann–Kendall (M–K) analysis is utilized to construct the dual criterion (∆α indicator criterion and ∆f(α) indicator criterion) for the tunnel deformation early warning study. In addition, the particle swarm optimization long-short-term memory (PSO-LSTM) prediction model is used for predicting tunnel settlement. The results show that, in reference to the tunnel warning level criteria and based on the Z-value results of the indicator criterion, the warning level of all four sections is class II. At the same time, through the analysis of tunnel settlement predictions, the PSO-LSTM model has a better prediction effect and stability for tunnel settlement. The predicted results show a slow increase in tunnel settlement over the next 5 days. Finally, the tunnel warning level and the predicted results of tunnel settlement are analyzed in a comprehensive manner. The deformation will increase slowly in the future. Therefore, monitoring and measurement should be strengthened, and disaster preparedness plans should be prepared. [ABSTRACT FROM AUTHOR]

In order to improve the stability, and sensitivity and response speed of moisture-sensitive sensors, the microarc oxidation process is used to realize the preparation of porous Al2O3 structure humidity-sensitive thin films on aluminum substrate and combined with magnetron sputtering process to realize the preparation of the humidity-sensitive sensor. After the Al2O3 moisture-sensitive films are prepared by the mechanical polishing, the microarc oxidation process platform and aging processes, moisture-sensitive films will be characterized by XRD and SEM. The results show that the peak intensity of α-Al2O3 diffraction peaks in Al2O3 humidity-sensitive thin films can be enhanced by increasing the microarc oxidation current. By building the humidity device platform for humidity-sensitive testing, the change of ambient humidity will lead to different changes of resistance and capacitance of the films, and the moisture-sensitive devices have better sensitivity at a lower frequency of 100 Hz. [ABSTRACT FROM AUTHOR]