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Objective Due to the characteristics of strong permeability and high water content in water-rich sand layer, the poor muck improvement can easily cause accidents such as spout spilling of screw conveyor and mud cake formation on the cutter plate during shield tunneling, thus affecting shield construction efficiency. So it is necessary to study the muck improvement of earth pressure balance shied tunnel in water-rich sand layer. Method Based on the typical water-rich sand layer working conditions in Qili Station-Minyuan Road West Station interval on Nanchang Metro Line 4, an indoor muck improvement experiment is carried out. The self-made shield soil chamber model device is used to implement soil chamber model experiments on different improved mucks. Based on muck pressure transfer characteristics, the correlations among slump, permeability coefficient and earth pressure transfer coefficient K0 of different improved mucks are established, and the improvement effect of muck under different K0 is studied. Result & Conclusion When foam is used alone to improve the muck, the transfer coefficient K0 of muck is positively correlated with slump, but negatively correlated with permeability coefficient of the muck. When the slump of the muck exceeds 200 mm, K0 decreases gradually. In order to achieve the ideal requirements of muck improvement for earth pressure balance shield in water-rich sand layer, the matched ratio of conditioners is suggested as follows: 25% of foam injection, or 10% injection rate of added bentonite mud. Laboratory and soil chamber model experiments show that the greater K0 is, the better the improvement effect of muck will be. In actual projects, the ideal K0 value of improved muck by using foam alone is 0.60-0.65. While foam and bentonite slurry are combined to improve the muck, the ideal K0 of improved muck is about 0.85.

Video Anomaly Detection (VAD) has been an active research field for several decades. However, most existing approaches merely extract a single type of feature from videos and define a single paradigm to indicate the extent of abnormalities. A coarse‐to‐fine three‐level prediction is built by integrating different levels of spatio‐temporal representations, better highlighting the difference between normal and abnormal behaviors. First, an object‐level trajectory prediction is proposed to model human historical position using a graph transformer network. Subsequently, skeleton‐level prediction is achieved by incorporating the positional information from the trajectory prediction. More importantly, based on the predicted skeleton, a skeleton‐guided pixel‐level region prediction is performed. A novel Skeleton Conditioned Generative Adversarial Network (SCGAN) is designed to explore the correlation between skeleton‐level and pixel‐level motion prediction. Benefiting from SCGAN, the prediction of human regions is contributed by both coarse‐grained and fine‐grained motion features. This three‐level prediction, namely Progressive Prediction Video Anomaly Detection (P3VAD), enlarges the prediction error on irregular motion patterns. Besides, a pixel‐level analysis method is proposed to achieve Background‐bias Elimination (BE) and denoise the predicted region. Experimental results validate the effectiveness of P3VAD on the four benchmark datasets (ShanghaiTech, CUHK Avenue, IITB‐Corridor, and ADOC). [ABSTRACT FROM AUTHOR]

Sodium ion capacitors (SICs) are designed to deliver both high energy and power densities at low cost. Electric double-layer capacitive cathodes are typically used in these devices, but they lead to very limited capacity. Herein, we apply a pseudocapacitive layered ferric vanadate (Fe-V-O) as cathode to construct non-aqueous SICs with both high energy and power densities. The Fe-V-O nanosheets cathode displays remarkable rate capability and cycling stability. The pseudocapacitive sodium storage mechanism of Fe-V-O, with over 83% of total capacity from capacitive contribution, is confirmed by kinetics analysis and ex situ characterizations. The capacitive-adsorption mechanism of hard carbon (HC) anode is demonstrated, and it delivers excellent rate capability. Based on as-synthesized materials, the assembled HC//Fe-V-O SIC delivers a maximum energy density of 194 Wh kg-1 and power density of 3,942 W kg-1. Our work highlights the advantages of pseudocapacitive cathodes for achieving both high energy and power densities in sodium storage devices.

To investigate the influence of pore size effect on dynamic response of saturated soil foundation, a model for predicting the dynamic response of the ground surface of the saturated soil foundation under incident P wave and SV wave is proposed based on the nonlocal-Biot theory. The analytical solution is obtained using the wave function expansion method. The influence of pore size described by nonlocal parameter, input frequency, and the incident angle on the dynamic response of displacement and stress is discussed in detail. The results show that at low frequencies, the calculation results of the nonlocal-Biot theory are basically the same as those of the classical Biot theory. At high frequencies, the surface displacement and stress change significantly with nonlocal parameters, that is, at high frequencies, the effect of pore size on the surface response cannot be ignored. The influence of incident wave frequency on the ground-surface response is related to pore size, that is, the larger the pore size, the more significant the frequency effect. The influence of SV wave on the dynamic response of ground surface is larger than that of P wave. Besides, the total reflection phenomenon is observed at an incident angle of 45° for the incident of SV wave. The results obtained in this work can provide reference for studying the problem of wave propagation in half-space saturated soil foundation.

Covalent organic frameworks (COFs) after undergoing the superlithiation process promise high‐capacity anodes while suffering from sluggish reaction kinetics and low electrochemical utilization of redox‐active sites. Herein, integrating carbon nanotubes (CNTs) with imine‐linked covalent organic frameworks (COFs) was rationally executed by in‐situ Schiff‐base condensation between 1,1′‐biphenyl]‐3,3′,5,5′‐tetracarbaldehyde and 1,4‐diaminobenzene in the presence of CNTs to produce core–shell heterostructured composites (CNT@COF). Accordingly, the redox‐active shell of COF nanoparticles around one‐dimensional conductive CNTs synergistically creates robust three‐dimensional hybrid architectures with high specific surface area, thus promoting electron transport and affording abundant active functional groups accessible for electrochemical utilization throughout the whole electrode. Remarkably, upon the full activation with a superlithiation process, the as‐fabricated CNT@COF anode achieves a specific capacity of 2324 mAh g−1, which is the highest specific capacity among organic electrode materials reported so far. Meanwhile, the superior rate capability and excellent cycling stability are also obtained. The redox reaction mechanisms for the COF moiety were further revealed by Fourier‐transform infrared spectroscopy in conjunction with X‐ray photoelectron spectroscopy, involving the reversible redox reactions between lithium ions and C=N groups and gradual electrochemical activation of the unsaturated C=C bonds within COFs. [ABSTRACT FROM AUTHOR]

Highlights: Novel laser-induced transfer method for fabricating glucose sensors from recycled e-waste copper, offering a sustainable and cost-effective solution. Unique heterogeneous CuxO nano-skeletons derived from discarded printed circuit boards exhibiting exceptional glucose-sensing performance (sensitivity: 9.893 mA mM−1 cm−2, detection limit: 0.34 μM). Miniaturized glucose detection device, optimized for scalability and portability, revolutionizing diabetes management and patient care. Electronic waste (e-waste) and diabetes are global challenges to modern societies. However, solving these two challenges together has been challenging until now. Herein, we propose a laser-induced transfer method to fabricate portable glucose sensors by recycling copper from e-waste. We bring up a laser-induced full-automatic fabrication method for synthesizing continuous heterogeneous CuxO (h-CuxO) nano-skeletons electrode for glucose sensing, offering rapid (< 1 min), clean, air-compatible, and continuous fabrication, applicable to a wide range of Cu-containing substrates. Leveraging this approach, h-CuxO nano-skeletons, with an inner core predominantly composed of Cu2O with lower oxygen content, juxtaposed with an outer layer rich in amorphous CuxO (a-CuxO) with higher oxygen content, are derived from discarded printed circuit boards. When employed in glucose detection, the h-CuxO nano-skeletons undergo a structural evolution process, transitioning into rigid Cu2O@CuO nano-skeletons prompted by electrochemical activation. This transformation yields exceptional glucose-sensing performance (sensitivity: 9.893 mA mM−1 cm−2; detection limit: 0.34 μM), outperforming most previously reported glucose sensors. Density functional theory analysis elucidates that the heterogeneous structure facilitates gluconolactone desorption. This glucose detection device has also been downsized to optimize its scalability and portability for convenient integration into people's everyday lives. [ABSTRACT FROM AUTHOR]

Rechargeable magnesium batteries (RMBs) are appealing alternatives for energy storage systems based on the high theoretical capacity, low price and high security of the Mg metal anode. Nevertheless, the shortage of high‐performance cathode materials severely obstructs its development. As an important conversion material, transition metal selenides, with desirable theoretical capacity and weak bond energy (Mg−Se), have attracted more attention in recent years. In this study, CuFeSe2 (CFS) nanoparticles were produced by a hydrothermal approach and its feasibility as a cathode material for RMBs was further investigated. Given the synergistic effect between Cu and Fe, the optimized CFS shows a reversible capacity of 120 mAh g−1 at 100 mA g−1, outstanding long‐term cyclability (86 mAh g−1 at 1 A g−1 after 600 cycles), and prominent rate capability (85 mAh g−1 at 1 A g−1). Density functional theory (DFT) computations conclude CFS exhibits a suitable migration barrier for Mg2+ along the tunnel of 0.92 eV. An in‐depth investigation of the mechanism demonstrates that the Mg storage process can be divided into solid solution reaction and the conversion processes by ex‐situ techniques. This work contributes to further investigate the Mg2+ storage mechanism of cathode materials for RMBs. [ABSTRACT FROM AUTHOR]

With the development of urban construction, uplift pile has been widely used in underground structure bearing buoyancy. The pile is buried deep underground, and the foundation pit is excavated on the pile foundation, the stress redistribution of the soil after the foundation pit excavation will reduce the lateral stress of the pile at the bottom of the pit, resulting in the reduction of friction resistance, but this effect is limited to a certain depth at the bottom of the foundation pit. Referring to the unloading influence depth corresponding to the vertical unloading coefficient in the spring back calculation of foundation pit and introducing the unloading influence depth corresponding to the horizontal unloading coefficient, it is deduced that the relationship between the horizontal unloading coefficient and the vertical unloading coefficient is based on the friction angle. Based on the bearing capacity control and numerical simulation, it is determined that the corresponding depth when the horizontal unloading coefficient is 0.95 is the unloading influence depth. The depth to width ratio of excavation has a great influence on unloading influence depth, and the internal friction angle of soil has little influence on unloading influence depth, while the influences of pile diameter and pile-soil friction coefficient can be ignored. The formula of unloading influence depth is derived in this paper. Comparing the unloading influence depth of sand and soft soil, the unloading influence depth of sand is greater than that of soft soil.