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Tungsten carbide is one of the most promising electrocatalysts for the hydrogen evolution reaction, although it exhibits sluggish kinetics due to a strong tungsten-hydrogen bond. In addition, tungsten carbide’s catalytic activity toward the oxygen evolution reaction has yet to be reported. Here, we introduce a superaerophobic nitrogen-doped tungsten carbide nanoarray electrode exhibiting high stability and activity toward hydrogen evolution reaction as well as driving oxygen evolution efficiently in acid. Nitrogen-doping and nanoarray structure accelerate hydrogen gas release from the electrode, realizing a current density of −200 mA cm −2 at the potential of −190 mV vs. reversible hydrogen electrode, which manifest one of the best non-noble metal catalysts for hydrogen evolution reaction. Under acidic conditions (0.5 M sulfuric acid), water splitting catalyzed by nitrogen-doped tungsten carbide nanoarray starts from about 1.4 V, and outperforms most other water splitting catalysts. Water electrolysis can generate carbon-neutral hydrogen gas from water, yet the required catalysts are often expensive, scarce, and poor at gas release. Here, the authors prepared nitrogen-doped carbon tungstide nanoarrays with high water-splitting activities and bubble-releasing surfaces.

The data-driven intelligent fault diagnosis method has shown great potential in improving the safety and reliability of train operation. However, the noise interference and multi-scale signal characteristics generated by the train transmission system under non-stationary conditions make it difficult for the network model to effectively learn fault features, resulting in a decrease in the accuracy and robustness of the network. This results in the requirements of train fault diagnosis tasks not being met. Therefore, a novel parallel multi-scale attention residual neural network (PMA-ResNet) for a train transmission system is proposed in this paper. Firstly, multi-scale learning modules (MLMods) with different structures and convolutional kernel sizes are designed by combining a residual neural network (ResNet) and an Inception network, which can automatically learn multi-scale fault information from vibration signals. Secondly, a parallel network structure is constructed to improve the generalization ability of the proposed network model for the entire train transmission system. Finally, by using a self-attention mechanism to assign different weight values to the relative importance of different feature information, the learned fault features are further integrated and enhanced. In the experimental section, a train transmission system fault simulation platform is constructed, and experiments are carried out on train transmission systems with different faults under non-stationary conditions to verify the effectiveness of the proposed network. The experimental results and comparisons with five state-of-the-art methods demonstrate that the proposed PMA-ResNet can diagnose 19 different faults with greater accuracy.

In the process of mineral resource extraction, monitoring surface deformation is crucial for ensuring the safety of engineering and ground infrastructure. Monitoring complete three-dimensional surface deformation is particularly significant. Traditional synthetic aperture radar (InSAR) technology provides deformation components only along the line of sight (LOS) and often lacks sufficient effective data in vegetation-covered mining areas and mining subsidence centers. To address this, this study proposes a method (SBAS-PIM) that combines SBAS-InSAR with the probabilistic integral method (PIM). This method leverages high-coherence points in mining areas and GNSS data from vegetation-covered regions to invert the parameters required by PIM, thus obtaining three-dimensional surface deformation results. The proposed method allows for the acquisition of three-dimensional deformation data with fewer InSAR points and GNSS data, significantly reducing labor costs and addressing the gap in InSAR monitoring of three-dimensional surface deformation in densely vegetated areas. Additionally, it accounts for the mutual influence of multiple adjacent working faces. Finally, through the application to a mining area in Heze, China, the maximum displacements in the vertical, east–west, and north–south directions were obtained as −2011, −418, and − 281 mm, respectively. The correlation coefficients between the vertical and east–west directions and GNSS data were both greater than or equal to 0.9, indicating that this method can effectively monitor the three-dimensional surface deformation of the mining area.

Oxygen evolution reaction is critical for water splitting or metal-air batteries, but previous research mainly focuses on electrode material or structure optimization. Herein, we demonstrate that surfactant modification of a NiFe layered double hydroxide (LDH) array electrode, one of the best catalysts for oxygen evolution reaction (OER), could achieve superaerophobic surface with balanced surface charges, affording fast mass transfer, quick gas release, and boosted OER performance. The assembled surfactants on the electrode surface are responsible for lowering the bubble adhesive force (∼ 1.03 µN) and corresponding fast release of small bubbles generated during OER. In addition, the bipolar nature of the hexadecyl trimethyl ammonium bromide (CTAB) molecule lead to bilayer assembly of the surfactants with the polar ends facing the electrode surface and the electrolyte, resulting in neutralized charges on the electrode surface. As a result, OH − transfer was facilitated and OER performance was enhanced. With the modified superaerophobic surface and balanced surface charge, NiFe LDHs-CTAB nanostructured electrode showed ultrahigh current density increase (9.39 mA/(mV cm 2 )), 2.3 times higher than that for conventional NiFe LDH nanoarray electrode), dramatically fast gas release, and excellent durability. The introduction of surfactants to construct under-water superaerophobic electrode with in-time repelling ability to the as-formed gas bubbles may open up a new pathway for designing efficient electrodes for gas evolution systems with potentially practical application in the near future.

With the accelerated urbanization process in Qingdao, urban land subsidence has damaged infrastructure and hindered the sustainable development. To prevent disasters caused by urban land subsidence, large-scale, long-term monitoring, mechanism analysis, and risk assessment are essential. This study proposes an improved time series Interferometric Synthetic Aperture Radar (InSAR) method, extracting Permanent Scatterers (PS) and Distributed Scatterers (DS) based on a two-layer network. Using Sentinel-1 dataset, Qingdao's land subsidence from 2019 to 2024 was monitored. The results were validated using multi-source data, and a comprehensive analysis of the spatiotemporal distribution and causes of subsidence was conducted ,alongside a risk matrix based on the Hurst index. Results show that combining PS and DS increases measurement density. From 2019 to 2024, Qingdao's land was generally stable, with subsidence mainly along Jiaozhou Bay , reaching a maximum rate of −84 mm/year due to urbanization and land reclamation. Two mechanisms were identified at Jiaozhou Bay Bridge: linear and seasonal cyclic subsidence. The urban land risk matrix revealed that most sampling points in seven subsidence areas remain in a dangerous state. This study systematically investigated  Qingdao's land subsidence, evaluated urban stability, and provided insights and solutions for subsidence prevention and control.

The electrical arcs generated by high-speed dynamic separation between pantograph and catenary systems pose a significant threat to the operational safety of high-speed railways. Environmental factors, particularly relative humidity and airflow, critically influence arc characteristics. This study establishes a two-dimensional pantograph–catenary arc model based on magnetohydrodynamic theory, validated through a self-developed experimental platform. Research findings demonstrate that as relative humidity increases from 25% to 100%, the core arc temperature decreases from 10,500 K to 9000 K due to enhanced heat dissipation in humid air and electron capture by water molecules; the peak arc voltage rises from 37.25 V to 48.17 V resulting from accelerated deionization processes under high humidity conditions; the average arc energy in polar regions increases from 2.5 × 10−4 J/m3 to 3.5 × 10−4 J/m3, exhibiting a saddle-shaped distribution; and the maximum arc pressure declines from 5.3 Pa to 3.7 Pa. Under airflow conditions of 10–30 m/s, synergistic effects between airflow and humidity further modify arc behavior. The most pronounced temperature fluctuations and most frequent arc root migration occur at 100% humidity with 30 m/s airflow, while the shortest travel distance and longest persistence are observed at 25% humidity with 10 m/s airflow, as airflow accelerates heat dissipation and promotes arc root alternation. Experimental measurements of arc radiation intensity and temperature distribution show excellent agreement with simulation results, verifying the model’s reliability. This study quantitatively elucidates the influence patterns of humidity and airflow on arc characteristics, providing a theoretical foundation for enhancing pantograph–catenary system reliability.

The optimal selection of multi-temporal differential interferogram series is an important step to monitor ground subsidence using the Stanford method for persistent scatterers (StaMPS)-based small baseline subset (SBAS) interferometric synthetic aperture radar (InSAR). Using a deformation model and its two solution methods, least squares and singular value decomposition, we present the composing mode and optimal selection of multi-temporal differential interferogram series and show that their quality and quantity affect the accuracy of monitored deformation information of SBAS InSAR. Using 29 ENVISAT ASAR images covering urban areas of Beijing, China, a different number of optimal multi-temporal differential interferogram series are formed to monitor urban ground subsidence by the StaMPS-based SBAS method. The comparison and verification of test results indicate that the quality and quantity of multi-temporal differential interferogram series substantially impact the singularity and degree of ill condition of the deformation model, locations of the selected slowly decorrelating filtered phase (SDFP) pixels, and monitored annual mean subsidence velocities. The suitable number of multi-temporal differential interferogram series under the optimal quality is 1-2 for a month in urban ground subsidence monitoring using StaMPS-based SBAS InSAR, a higher quantity of differential interferograms of the optimal quality is not always better.

Oil well wax removal technology is an important subject in the process of oil field exploitation. This paper analyzes the mechanism and characteristics of wax formation in oil Wells by measuring the amount of wax in crude oil in Baiwolcheng oil area. When the waxy component, which usually exists in liquid form, is accompanied by crude oil from underground to the ground, the waxy crystal precipitates and deposits in the inner wall of oil pipe due to the gradual decrease of the temperature of crude oil. The phenomenon of paraffin formation, paraffin formation process and paraffin formation law of oil well are studied, and chemical paraffin removal and anti-wax technology is determined as the main research object, evaluation and optimization of paraffin removal and anti-wax agent, and determination of dosage concentration and dosage.

The authors describe an aptamer based method for the determination of the antibiotic sulfadimethoxine (SLF). It is making use of upconversion nanoparticles (UCNPs) that act as an internal fluorophors signals, and of aptamers that can specifically recognize SLF. The UCNPs were deposited on the surface of magnetic nanoparticles (magNPs) functionalized with the aptamer. In the presence of SLF, parts of the UCNPs dissociate from the surface of the magNPs, and this results in decreased fluorescence intensity. The findings were exploited to design a fluorometric assay for SLF that has a 0.11 ng·mL −1 detection limit. The method was successfully applied to the quantification of SLF in spiked samples of perch and catfish. Recoveries range from 80.3% to 92.7%, and RSDs from 2.4% to 3.6%. Graphical Abstract Schematic of an aptamer based method for the determination of the antibiotic sulfadimethoxine (SLF). It is making use of upconversion nanoparticles (UCNPs) that act as an internal fluorophors signals, and of aptamers that can specifically recognize SLF.

With the development of detection and identification technology, infrared stealth is of great value to realize anti-reconnaissance detection of military targets. At present, infrared stealth materials generally have deficiency, such as complex structure, inconvenient radiation regulation and cumbersome preparation steps, which greatly limit the practical application of infrared stealth materials. In view of the above deficiency of infrared stealth materials, we proposed a kind of multilayer film for infrared stealth using VO 2 thermochromism based on the temperature response mechanism of tuna to adjust its color, and through the intelligent reversible radiation regulation mechanism to meet the infrared stealth requirements of tanks in different actual scenes. The results show that when the temperature increases from 300 K to 373 K, the peak emissivity of the film decreases from 94% to 20% in the 8–14 µm band after structural optimization, which can realize the infrared stealth of the high temperature target in the 8–14 µm band. The average emissivity of the multilayer film for infrared stealth at 3–5 µm and 8–14 µm band can be reduced to 34% and 27% at 373 K, and the peak emissivity at 5–8 µm band can reach 65%, realizing dual-band infrared stealth in the 3–5 µm and 8–14 µm bands and heat dissipation in the 5–8 µm band. The multilayer film for infrared stealth based on VO 2 thermochromism designed by the authors can meet the characteristics of simple film structure, convenient radiation regulation and simple preparation.