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Abstract Bound states in the continuum (BICs), referring to spatially localized bound states with energies falling within the range of extended modes, have been extensively investigated in single-particle systems, leading to diverse applications in photonics, acoustics, and other classical-wave systems. Recently, there has been theoretical interest in exploring many-body BICs in interacting quantum systems, which necessitate the careful design of impurity potentials or spatial profiles of interaction. Here, we propose a type of many-body BICs localized at boundaries, which can be purely induced by the uniform onsite interaction without requiring any specific design of impurity potential or nonlocal interaction. We numerically show that three or more interacting bosons can concentrate on the boundary of a homogeneous one-dimensional lattice, which is absent at single- and two-particle counterparts. Moreover, the eigenenergy of multi-boson bound states can embed within the continuous energy spectra of extended scattering states, thereby giving rise to interaction-induced boundary many-body BICs. Furthermore, by mapping Fock states of three and four bosons to nonlinear circuit networks, we experimentally simulate boundary many-body BICs. Our findings enrich the comprehension of correlated BICs beyond the single-particle level, and have the potential to inspire future investigations on exploring many-body BICs.

C26H26N6O5, monoclinic, P21/c (no. 14), a = 10.9393(1) Å, b = 16.8724(2) Å, c = 13.5836(2) Å, β = 102.843(1)°, V = 2444.43(5) Å3, Z = 4, R gt(F) = 0.0318, wRref (F 2) = 0.0827, T = 173 K.

A multi-stage planning method for independent energy storage (IES) based on dynamically updating key transmission sections (KTS) is proposed to address issues such as uneven power flow distribution and transmission congestion resulting from the high penetration of renewable energy sources and load growth. First, an IES planning model considering KTS constraints is established by searching and updating the KTS and associated constraints. This model takes into account IES investment and operation costs, maintenance costs, revenue from spot price differences, and penalties for system congestion. Then, a multi-stage planning method for energy storage is proposed based on the dynamic updating of KTS and the annual planning results. To verify the effectiveness and feasibility of the proposed method, a case study simulation is conducted using the improved IEEE 39-bus New England standard system. The results demonstrate the ability of the method to achieve multi-stage rolling optimization of IES, providing a reference for future efforts toward multi-stage planning of IES.

Abstract Herein, the Z11 argument tangent is proposed as a novel criterion for assessing energy loss (absorption) of the reciprocal two‐port networks composed of the shielding material. With a simple mathematical deduction, it can be found that the relationship between the network absorption and the Z11 argument tangent is inverted. The absorption decreases with increasing the Z11 argument tangent, and the Z11 argument is approximately equal to the power factor angle. Additionally, a series of samples are presented to verify their absorptions and the Z11 argument tangents. The numerical simulations on other works are also presented to calculate the Z11 argument tangent and validate the relationship between the Z11 argument tangent and electromagnetic absorption from another side. The experiment and simulation results agree well with that of the mathematical deduction. The findings can be applied in most passive shielding materials and provide a promising approach to guiding and developing absorption‐dominated electromagnetic shielding materials for next‐generation communication applications.

Photonic reservoir computing (RC) is a simple and efficient neuromorphic computing framework for human cortical circuits, which is featured with fast training speed and low training cost. Photonic time delay RC, as a simple hardware implementation method of RC, has attracted widespread attention. In this paper, we present and experimentally demonstrate a time delay RC system based on a Fabry Perot (FP) laser for multiple tasks processing. Here, the various tasks are attempted to perform in parallel in the multiple longitudinal modes of the FP laser. It is found that the time delay RC system based on the FP laser can successfully handle different tasks across multiple longitudinal modes simultaneously. The experimental results demonstrate the potential of the time delay RC system based on the FP laser to achieve multiple tasks processing, providing various possibilities for improving the information processing ability of neural morphology RC systems, and promoting the development of RC systems.

Polypropylene (PP) is considered to be a rather promising material for HVDC cable insulation. Grafting modi-fication has proved to be an effective method on the electrical property improvements of PP. This paper reports on the highly-enhanced electrical properties of styrene-grafted polypropylene (PP-g-St) and their related mechanism. The influence of grafting styrene on crystallization structures, thermal properties and electrical properties of PP-g-St are characterized and analyzed. These results show that PP-g-St exhibits remarkably enhanced DC volume resistivity, suppressed space charge accumulation and improved DC breakdown strengths as compared to PP. Crystallization observation shows PP-g-St has small, imperfect spherulites with indistinct boundaries, which is strongly correlated to enhanced electrical properties. This study provides an effective grafting strategy to design high-performance HVDC cable insulation materials for bulk power transmission systems.

Separation flow in a curved duct is a common phenomenon in engineering applications, and it highly contributes to the performance of fluid machinery. Accurate prediction of curved duct flows using the computational fluid dynamics method remains a challenge due to the limitations of turbulence modeling. Hence, the high-fidelity method of the delayed detached eddy simulation (DDES) approach is employed to simulate the U-duct flow with a Reynolds number of 105. The DDES results are compared with experimental data from the study by Monson et al. (1990) and analyzed in detail. The Q-criterion is defined to analyze the vortex structures and study the mechanism in the flow separation region. Discussions are made on turbulence characteristics, including turbulence energy spectra, helicity density, and turbulence anisotropy in the U-duct flow. Results indicate that the regions near the wall and within flow separation are highly anisotropic. The turbulence near the wall region is in a two-dimensional state, and the turbulence within the flow separation region is in a “rod-like” state.

As China accelerates its transition to a low-carbon society, its power system is facing growing challenges in terms of maintaining adequacy amid a rapidly evolving energy structure. The concept of adequacy, traditionally focused on power capacity and generation, has broadened to include dimensions like flexibility and inertia. Against this backdrop, optimizing the integration of coal power and renewable energy to meet the system’s needs for adequacy, flexibility, and frequency stability has become a critical research area. This paper introduces the concept of “Generalized Adequacy”, expanding the traditional understanding of adequacy, and proposes an optimization model for the coordinated development of coal power and renewable energy based on this concept. This study examines the effects of extreme weather, renewable energy penetration, wind–solar ratios, and generalized adequacy constraints using a case study from a central region of China. The findings reveal that extreme weather conditions drive an increase in photovoltaic installations, while higher renewable energy penetration leads to more wind power installations. Accounting for generalized adequacy constraints can moderate the retirement of coal-fired plants, reducing unnecessary inertia support in normal conditions and ensuring dynamic frequency stability during extreme weather events.

In this study, a single-outer-spiral electrode with inductance of 20 μH is employed to couple the energy input of a bipolar nanosecond pulse for the purpose of generating a large-scale atmospheric pressure plasma jet. When the spiral electrode is wrapped around a plasma jet tube with a length of 35 cm, the electrical field can be optimized, resulting in a stable laminar flow field, and a plasma jet with a length and diameter larger than 14 cm and 1.2 cm can be generated. A comparative study of the bipolar and unipolar pulse excitation voltages is also conducted, showing that the maximum lengths of the plasma jet excited by a bipolar pulse voltage, positive pulse voltage, and negative are 14 cm, 10 cm, and 7 cm, respectively. The temporal and spatially resolved spectra of the plasma jets excited by both bipolar and unipolar pulses are investigated, respectively, and the main physiochemical processes of the active species and the plasma dynamics’ evolution are discussed.

The water jet nozzle is a penetrating drilling tool, which sends the pumped water to the nozzle through a high-pressure hose. It can work in a variety of working environments. When it dredges the blockage in the pipeline, its structural parameters will affect the jet flow field in the pipeline. Taking the self-propelled water jet nozzle as the research object, SolidWorks was used to establish the nozzle model with different parameter structures. Based on Fluent, the k-ε turbulence model was used to simulate the jet of nozzles with different nozzle sizes and arrangements in the pipeline. The distribution of the jet flow field and the change in velocity and displacement of nozzles with different parameters in the pipeline were compared, and then computational fluid dynamics (CFD) were used to process the simulation data for further research. The results show that when the inclination angle of the rear nozzle is 35°, the attenuation of the front jet velocity and the fluctuation of the wall fluid velocity are the smallest. When the nozzle aperture is increased from 2 mm to 3.5 mm, the vortex area inside the pipe is reduced, and the velocity attenuation of the front jet is also reduced, with the velocity attenuation rate decreasing by about 10%. This study provides a reference for the design and parameter optimization of self-propelled water jet nozzles.

Strong turbulence is generated by the blending of opposed staggered jets (OSJs). This turbulence results in fluid mixing and energy dissipation, which are crucial for pollutant dilution and the filling of navigation lock chambers. A renormalization group k-ε turbulence model is adopted to conduct three-dimensional simulations of OSJs at various stagger distances. The blending characteristics of two square water jets at eight stagger distances L* within a finite field are examined; here, L* is defined as the distance between the center lines of the staggered jets divided by the jet diameter. The initial Reynolds number and inlet diameter of the jets for the numerical simulations are set to 2.99 × 106 and 0.6 m, respectively. The numerical results show that there is a linear correlation between the decay exponent and the jet half-width, both of which increase and then gradually stabilize with increasing L*. Intriguingly, the vortex strength and blending length both increase at first before decreasing as L* increases, and the blending effectiveness distribution mirrors these fluctuations. Moreover, a decay model for the axial velocity is formulated in terms of the decay exponent and L*. These investigations yield substantial theoretical results underpinning fluid mixing and orifice arrangement in navigation lock chambers.

Cyber-Physical-Social Systems (CPSS) epitomize the modern era’s intelligent connectivity. They integrate physical devices, computer networks, and social networks, forming an innovative paradigm for intelligent systems. Utilizing CPSS to enhance intelligence, automation, and remote services in healthcare represents a primary research focus. Pulmonary embolism, a prevalent condition resulting from the blockage of the pulmonary artery and its branches by emboli, leads to a spectrum of clinical syndromes marked by impaired pulmonary circulation and right heart dysfunction, contributing to sudden and unpredictable fatalities. Nevertheless, the diagnosis of pulmonary embolism remains challenging due to non-specific clinical presentations, constrained diagnostic capabilities, delayed diagnoses, insufficient physician knowledge, and suboptimal diagnostic techniques. Consequently, we introduce the innovative LSCU-Net architecture within the CPSS framework, designed to develop an automated segmentation and intelligent assessment system for pulmonary embolism, facilitating its automated and intelligent detection. The experimental findings demonstrate that the model accurately segments pulmonary embolism, evidenced by a Jaccard index of 0.6958, a Dice coefficient of 0.8193, a Mean Pixel Accuracy (mPA) of 0.8519, and an accuracy of 0.9993. Empirical studies reveal that our proposed model substantially surpasses existing models in performance. Consequently, this model can aid physicians in the diagnosis of pulmonary embolism during clinical practice. The established pulmonary embolism automatic segmentation and assessment system also showcases the application successes of CPSS in intelligent remote healthcare. The system’s development and deployment not only streamline physicians’ diagnostic processes but also elevate public health standards and advance CPSS research within the medical domain.

Clock noise is one of the dominant noises in the space-borne gravitational wave (GW) detection. To suppress this noise, the clock noise-calibrated time-delay-interferometry (TDI) technique is proposed. In this technique, an inter-spacecraft clock tone transfer chain is necessary to obtain the comparison information of the clock noises in two spacecraft, during which an electro-optic-modulator (EOM) is critical and used to modulate the clock noise to the laser phase. Since the EOM sideband modulation process introduces the extra modulation noise, it may limit the experimental demonstration of the suppression effect of the clock noise, and further affect the space-borne GW detection. To solve this problem, it is significant to put forward the modulation noise requirement and test whether the experimental components meet or not. In this work, based on the typical Michelson TDI algorithm and the fundamental noise requirement of GW detectors, the analytic expression of the modulation noise requirement is strictly derived, relaxing the specification compared to the commonly used rough assessments. Furthermore, a method is provided to experimentally test EOM modulation noise, and a commercial EOM (iXblue-NIR-10 GHz) is tested. The experimental results show that it can meet the requirement of the typical GW detection mission LISA in the whole scientific frequency bandwidth by taking the optimal combination of the data streams.

The measurement of the rotational velocity using the rotational Doppler effect (RDE) of a vortex beam is easily affected by atmospheric turbulence, leading to dispersed orbital angular momentum (OAM), and reduced measurement accuracy. This study investigates the optimal ability of the Gerchberg-Saxton (GS) phase retrieval algorithm to compensate for the optical field and enhance the velocity measurement accuracy within the optimal range of intrinsic parameters, such as the number of GS iterations, and extrinsic parameters, such as the atmospheric turbulence intensity and beam properties. Through detailed theoretical and simulation analyses, we demonstrate the outstanding effectiveness of the GS algorithm in improving the velocity measurement accuracy. Simulations conducted for a system-target distance of zS-T = 500 m show a 29.88% improvement in the velocity measurement accuracy and a 1.03-fold increase in the spectral signal-to-noise ratio (SSNR) within the optimal range. It showcases advantages that set it apart from other methods. This study reveals the threshold of the ability of GS algorithm to significantly enhance the rotational velocity measurement accuracy, providing valuable insights to precision measurements of rotational velocities in free-space applications.

C23H25BrO6, triclinic, P1‾$\overline{1}$ (no. 2), a = 7.8451(3) Å, b = 7.9428(2) Å, c = 17.6360(6) Å, α = 90.146(3), β = 90.433(3)∘, γ = 99.307(3)∘, V = 1084.44(7) Å3, Z = 2, Rgt(F) = 0.0464, wRref(F2) = 0.1402, T = 297.37(10) K.

The impact of contact between two elastic–plastic bodies is highly complex, with no established theoretical contact model currently available. This study investigates the problem of an elastic–plastic sphere impacting an elastic–plastic half-space at low speed and low energy using the finite element method (FEM). Existing linear contact loading laws exhibit significant discrepancies as they fail to consider the impact of elasticity and yield strength on the elastic–plastic sphere. To address this limitation, a novel linear contact loading law is proposed in this research, which utilizes the concept of equivalent contact stiffness rather than the conventional linear contact stiffness. The theoretical expressions of this new linear contact loading law are derived through FEM simulations of 150 sphere and half-space impact cases. The segmental linear characteristics of the equivalent contact stiffness are identified and fitted to establish the segmental expressions of the equivalent contact stiffness. The new linear contact loading law is dependent on various factors, including the yield strain of the half-space, the ratio of elastic moduli between the half-space and sphere, and the ratio of yield strengths between the half-space and sphere. The accuracy of the proposed linear contact loading law is validated through extensive Finite Element Method simulations, which involve an elastic–plastic half-space being struck by elastic–plastic spheres with varying impact energies, sizes, and material combinations.

In order to solve the ecological environment pollution caused by a large amount of coal gangue accumulation and the problems of poor conveying performance and low support strength of paste filling materials. Based on the standard slump test and uniaxial compressive strength test, the slump and compressive strength (post-coagulation) of gangue paste under different aggregate size aggregations were obtained through orthogonal experiments in this study. The results show that the slump of the gangue filling paste with four types of aggregate size gradations is negatively correlated with the mass fraction, and the slump of the filling paste with a coarser aggregate content is more obviously affected by the mass fraction The increase of fine aggregate content has a significant impact on the compressive strength of the filling paste, which shows a trend of first increasing and then decreasing. When the mixing ratio of coarse aggregate and fine aggregate is 5:5, the compressive strength of the paste reaches the best. In addition, different proportions of aggregate mixing cause the filling paste to form different skeleton structures, including the skeleton void structure at 7:3 or 6:4, the skeleton dense structure at 5:5, and the skeleton suspension structure at 4:6, which are decisive for the final performance of the paste. By analyzing the experimental results of the compressive strength and slump of the gangue filling paste, it was found that the relationship between the compressive strength and slump of the gangue filling paste is a power index function. Through data fitting, it was found that the regression coefficient of the fitting function is no less than 0.97, and the fitting effect is good for evaluating the strength of the filling paste under the aggregate size grading.

In this paper, bismuth (Bi) was successfully deposited on graphite felts to improve the electrochemical performances of vanadium redox flow batteries. Modified graphite felts with different Bi particle loadings were obtained through electrochemical deposition at voltages of 0.8 V, 1.2 V and 1.6 V in 0.1 M BiCl3 solution for 10 min. The optimal Bi particle loading was confirmed by scanning electron microscopy (SEM), single cells and electrochemical tests. The SEM images revealed the deposition of granular Bi particles on the fiber surface. The Bi-modified felts which were electro-chemically deposited at 1.2 V (Bi/TGF-1.2V) showed excellent electrochemical performances in cyclic voltammetry curves and impedance spectroscopy. Meanwhile, the single cells assembled with Bi/TGF-1.2V as negative electrodes exhibited higher voltage efficiencies than the others. The optimized Bi particle loading induced better catalysis of the V3+/V2+ reaction and hence significantly improved the cell performances. In addition, the prepared Bi-modified felts showed stable cell performances and slower charge–discharge capacity declines than the other electrodes at current densities between 20 mA/cm2 and 80 mA/cm2. Compared with the pristine felt, the voltage efficiency of the vanadium redox flow battery assembled with Bi/TGF-1.2V graphite felt was 9.47% higher at the current density of 80 mA/cm2. The proposed method has considerable potential and guiding significance for the future modification of graphite felt for redox flow batteries.

Non-thermal plasma driven ammonia synthesis has great potential for future industrial applications due to its low theoretical energy requirements. To achieve technological advancement and environmental sustainability, it is crucial to boost the energy yield in plasma-assisted ammonia synthesis. Therefore, optimizing energy transfer and utilization are key strategies for enhancing energy efficiency. In this study, dielectric barrier discharge driven by a nanosecond pulsed power supply is used to enhance plasma-assisted ammonia synthesis by controlling the energy transfer through the addition of noble gases. It was found that the addition of noble gases changed the plasma characteristics, significantly improved the uniformity of the discharge, and achieved a high energy yield for ammonia synthesis. The effects of additive amounts of argon (Ar) and helium (He), as well as the pulse parameters including the pulse voltage, pulse repetition frequency, pulse width, and pulse rise time on the energy yield of ammonia synthesis are discussed. The inclusion of noble gases expanded the pathway for gas-phase reactions, with the active components of critical reactions examined through optical emission spectra. This analysis revealed an increased presence of both N2+ and N2* particles in the reaction’s rate-limiting step, attributed to the addition of noble gases. Finally, a zero-dimensional (0D) plasma chemical kinetic model was established to investigate the influence of Ar addition on the reaction mechanism of ammonia synthesis.

In the impinging region of opposing jets, strong mixing and significant energy dissipation are observed, but the mixing parameters invariably change with the opposed impinging strength (OIS). In this paper, the ratio of the turbulent kinetic energy (TKE) intensity at the theoretical impinging point to the nozzle exit is defined as the opposed impinging strength. To examine the mixing properties of opposed impinging jets (OIJs) in a limited field under various OIS, a renormalization group k-ε turbulence model is employed to calculate three-dimensional OIJs under various OIS. The nozzle exit diameter is set to 0.6 m, and the inlet velocity is between 0.08 and 8 m/s, so the simulations are performed at Re between 4.8 × 104 and 4.8 × 106. This work focuses on the radial and vertical jets produced after impinging as well as the distribution of the TKE, flow field, and vortices. A thorough investigation reveals that although the OIS of the jets is primarily determined by the degree of jet development, it increases with the Reynolds number. A low OIS results in less mixing in the surrounding water and relatively unconstrained jet generation; however, it also results in limited energy extraction from the fluid. Once the OIS is high, there is more mixing in the surrounding water, and more energy is also lost during impinging. The distribution of vortices in the vortex field is not only influenced by the OIS but is also very closely related to the scale of the limited mixing field.

The strength of the phonon anharmonic effect of the pristine FeSi2 and Co-doped Fe0.94Co0.06Si2 is investigated by a Raman scattering study on the vibrational properties of those materials in the temperature range of 300–1523 K. All the vibrational modes exhibit significant redshifts with increasing temperature, and their spectral widths increase simultaneously. The structure transition from the semiconducting β phase to the metallic α phase is evidenced by the sudden disappearance of the vibrational modes. The extended Klemens model is applied to study the anharmonic effect on the phonon frequency shift and damping constant, and the four-phonon decaying process is expected to be the dominant one after doping the metal Co. Such an enhancement is also suggested contributing to the reduction of the thermal conductivity in Fe0.94Co0.06Si2. In addition, the vibrational properties of the mode at 250 cm−1 are more sensitive to the anharmonicity effect than that of the mode at 195 cm−1. This work provides valuable insights for understanding the high-order anharmonic effects in thermoelectric materials, especially in chemically doped materials.

As an important unconventional resource, shale gas can alleviate energy shortage, and its efficient development ensures the long-term growth of oil and gas. The prediction of production levels and estimated ultimate recovery with high accuracy is necessary for shale gas development. Conventional methods are widely applied in the oil and gas industry owing to their simplicity and effectiveness; however, none of them can accurately predict the results for frac hits affected wells. In this work, a probability method based on the numerical model of shale gas reservoir has been formed. In view of the impact of frac hits on the productivity of production wells during the development of shale gas reservoirs, an embedded discrete fractured numerical simulation method for gas reservoirs is proposed to simulate the geological engineering parameter range of wells before frac. And aiming at the established numerical model of shale gas reservoir, this method adopts the ensemble smoother with multiple data assimilation automatic history matching technology to carry out the history matching process of the model. Based on the probability theory and numerical simulation results, this study analyses the influence of different distribution functions of parameters on the calculation results of reserves, and obtains the expected curve of reserves through combination calculation. Besides, the effectiveness of this method was verified by comparing with other traditional predicted method.

This paper is aimed at studying the concept of multihyperuniformity and applying it to the design of shared-aperture antenna arrays and multi-bit coding metasurfaces. By formulating the theoretical foundation and essential geometric aspects related to this distribution, we create a computational model capable of generating both single hyperuniform and multihyperuniform distributions. Moreover, we put forward specific convergence acceleration techniques that effectively minimize computational time, particularly when dealing with a substantial number of elements. Considering the shape, size, and corresponding geometric constraints of the elements, we generate patterns suitable for practical designs of antenna arrays, as well as metasurfaces. We present an example of a multihyperuniform shared-aperture antenna array as illustration. Specifically, a penta-band circular patch antenna array operating in the C-band with low sidelobes and high realized gain over five different frequency bands is demonstrated. The computational model is also implemented for the design of a multi-bit coding metasurface with scattering reduction attributes.

The approach of dynamic tracking and counting for obscured citrus based on machine vision is a key element to realizing orchard yield measurement and smart orchard production management. In this study, focusing on citrus images and dynamic videos in a modern planting mode, we proposed the citrus detection and dynamic counting method based on the lightweight target detection network YOLOv7-tiny, Kalman filter tracking, and the Hungarian algorithm. The YOLOv7-tiny model was used to detect the citrus in the video, and the Kalman filter algorithm was used for the predictive tracking of the detected fruits. In order to realize optimal matching, the Hungarian algorithm was improved in terms of Euclidean distance and overlap matching and the two stages life filter was added; finally, the drawing lines counting strategy was proposed. ln this study, the detection performance, tracking performance, and counting effect of the algorithms are tested respectively; the results showed that the average detection accuracy of the YOLOv7-tiny model reached 97.23%, the detection accuracy in orchard dynamic detection reached 95.12%, the multi-target tracking accuracy and the precision of the improved dynamic counting algorithm reached 67.14% and 74.65% respectively, which were higher than those of the pre-improvement algorithm, and the average counting accuracy of the improved algorithm reached 81.02%. The method was proposed to effectively help fruit farmers grasp the number of citruses and provide a technical reference for the study of yield measurement in modernized citrus orchards and a scientific decision-making basis for the intelligent management of orchards.

One important task for autonomous driving is the precise detection and recognition of road traffic signs. This research focuses on a comprehensive set of 72 distinct traffic signs that are prevalent on urban roads in China, with the goal of developing an enhanced You Only Look Once (YOLO) network model tailored for this specific task. The modifications include the omission of the terminal convolution module and Conv3 (C3) module within the backbone network. Additionally, the 32-fold downsampling is replaced with a 16-fold downsampling, and a feature fusion module with dimensions of 152 × 152 is introduced in the feature layer. To capture a more encompassing context, a novel hybrid space pyramid pooling module, referred to as Hybrid Spatial Pyramid Pooling Fast (H-SPPF), is introduced. Furthermore, a channel attention mechanism is integrated into the framework, combined with three other improved methodologies. Upon evaluation, the enhanced algorithm demonstrates impressive results, achieving a precision rate of 91.72%, a recall rate of 91.77%, and a mean average precision (mAP) of 93.88% at an intersection over union (IoU) threshold of 0.5. Additionally, the method also achieves an mAP of 75.81% for a variety of IoU criteria between 0.5 and 0.95. These achievements are validated on an augmented dataset established for this study.

This paper proposes a fundamental investigation of coal gangue and fly ash impact on B. pasteurii to enhance the properties of backfill materials. The goal is to obtain effective microbial mineralization and potential mechanical properties of coal gangue and fly ash as backfill materials and to mitigate the impact of the most common binders used in the backfill material of mines. Micro-scale mineralization was performed with B. pasteurii bacteria using microbially induced carbonate precipitation (MICP) technology to clarify solid waste impact on B. pasteurii and to bind coal gangue and fly ash. Several tests were carried out to analyze the behavior of B. pasteurii, especially when it coexists with these two waste materials separately. In such cases, it was possible to observe a reduction in mineralization initiation time with respect to the natural mineralization of the MICP technology. Moreover, at the macro-scale, the new mineralized backfilling material shows good workability in the fresh state, whereas the strength at 28 days is 5.34 times higher than that obtained with non-mineralized coal gangue and fly ash.

C17H13NO3, monoclinic, P21/c (no. 14), a = 9.5306(2) Å, b = 6.1971(2) Å, c = 23.3849(7) Å, β = 101.445(3)°, V = 1353.70(7) Å3, Z = 4, Rgt(F) = 0.0644, wRref(F2) = 0.1909, T = 120 K.

Identifying the key nodes in complicated networks is an essential topic. A number of methods have been developed in recent years to solve this issue more effectively. Multi-attribute ranking is a widely used and efficient method to increase the accuracy of identifying the key nodes. Using k-shell iteration information and propagation threshold differences, we thoroughly analyze the node’s position attribute and the propagation attribute to offer a hybrid influence method based on information entropy. The two attributes will be weighted using the information entropy weighting method, and then the nodes’ influence ranking will be calculated. Correlation experiments in nine different networks were carried out based on the Susceptible–Infected–Recovered (SIR) model. Among these, we use the imprecision function, Kendall’s correlation coefficient, and the complementary cumulative distribution function to validate the suggested method. The experimental results demonstrate that our suggested method outperforms previous node ranking methods in terms of monotonicity, relevance, and accuracy and performs well to achieve a more accurate ranking of nodes in the network.

The identification of key nodes in complex networks is a hot topic. Therefore, it attracts increasing attention from different fields, like airline networks and social networks. To identify the key nodes in complex network, we suggest an improved gravity model method that takes propagation features into account. Relevant experiments were carried out in four actual airline networks based on the Susceptible Infected Recovered (SIR) model. First, we analyze the correlation between the proposed method and other benchmark methods.Then, Kendall’s correlation coefficient and the imprecision function were used as evaluation metrics to analyze and validate the proposed method. Empirical results reveal that the suggested method outperforms previous benchmark methods in terms of precision and effectiveness for identifying key nodes, especially in the US air network, where Kendall’s tau achieves a 107% improvement compared to the gravity centrality method.

C26H41NO8, orthorhombic, P212121 (no. 19), a = 8.24370(10) Å, b = 13.1867(2) Å, c = 22.8490(4) Å, V = 2483.85(6) Å3, Z = 4, Rgt (F) = 0.0357, wRref (F 2) = 0.0975, T = 169.99(10) K.

In this study, a method of stabilizing the output beam of a large-mode-area fiber amplifier operating above the mode instability threshold is demonstrated. A mode control system based on the photonic lantern is used to excite dynamic mode beatings as the seeding stage of a 42/250 µm Yb-doped fiber amplifier. We propose a theoretical explanation for the validity of this method: provided that the mode interference patterns generated by input mode beatings are antisymmetric to those in the main amplifier caused by thermally induced non-linear effects, the refractive index grating will not be formed to indicate the onset of mode instability. Experimentally, significant mode stability and beam quality improvement have been achieved in this system at power levels of up to nearly four times the mode instabilities threshold.

In this paper, novel two-dimensional single-phase three-ligament, four-ligament and six-ligament chiral structure models are proposed. The advantage is that it is easy to manufacture with few components, has good sound insulation and vibration damping performance, and is more practical. The dispersion information of the structure is calculated by combining Bloch's theorem and the finite element method. By varying the geometric parameters of the new structural single-cell and simulating the vibration transmission of the finite period structure to check the vibration suppression capability of the optimized structure. Three combined structures were constructed to compare their energy band properties with the base structure. The wave propagation characteristics within the combined structure are also analyzed by comprehensive means. It is shown that the optimized structure has a significantly lower bandgap down to below 1 kHz and a significantly wider bandgap width up to 3.6 kHz. The combined structure can open up a wider omnidirectional bandgap for multi-frequency and broadband vibration attenuation. The flexibility of the structure combination gives it a large potential for use, providing a new solution for broadband and multi-frequency vibration and noise reduction, while plane wave analysis provides theoretical support for structural optimization.

Abstract Secondary electromagnetic reflection is a great challenge in the field of high conductivity electromagnetic interference (EMI) material due to the poor electromagnetic absorption ability. In this work, a multilayer stack strategy compositing of the absorption‐dominated thin films and the reflection‐dominated thick film is proposed to realize both high shielding effectiveness (SE) and low reflection. The film comprises 3D woven silver nanowire (AgNWs) networks embedded in the polydimethylsiloxane (PDMS) substrate, and the shielding film thickness can be adjusted via controlling coating cycles. It can be found the three‐ply stack of two thin films and a thick film, (B:F)10(B:F)10(B:F)40, (B:F)5(B:F)10(B:F)40, and (B:F)5(B:F)5(B:F)40, can achieve EMI SEs up to 40.8, 40.7, and 36.3 dB, and the absorptions up to 0.59, 0.65, and 0.69, respectively. Results from verification investigation and theoretical simulation indicate that the multilayer can regulate the shielding mechanism of AgNWs‐based films from reflection‐dominated to absorption‐dominated, with no apparent deterioration of EMI SE. The synergistic effect of a multilayer stack is regarded to originate from a special “absorb‐absorb‐reflect‐absorb‐absorb” course. This finding suggests a promising approach to acquiring both high‐efficient and absorption‐dominated EMI shielding material.

While cervical total artificial disc replacement potentially preserves motion of the natural intervertebral disc (IVD), problems also arise involving alterations of the spinal biomechanics. A major challenge lies in restoring mechanics of the natural IVD with appropriate kinematics and biomimetic configuration. A biomimetic artificial IVD model is designed and fabricated using a 3D braided fibrous scaffold and a self‐healable hydrogel matrix. The artificial IVD is characterized by 3D four‐directional fibrous structure resembling natural annulus fibrosus and self‐healable hydrogel‐mimicking natural nucleus pulposus. In the compression tests, the artificial IVD exhibits reasonable mechanical behaviors and desired viscoelastic behaviors similar to the natural IVD. After fatigue loading of 5 million cycles, the artificial IVDs become stiffer, whereas the mechanical values remain within the reasonable range. Finite‐element analysis of the artificial IVD from mesoscale and macroscale analysis indicates the coherent load transfer through both the interconnections within the fiber mesh and the fiber–matrix interface, and the entire IVD shows a stress profilometry similar to natural IVD. In conclusion, a biomimetic prototype of artificial IVD with nature‐mimicking mechanics and structure is fabricated. The presence of interwoven fibrous mesh, hydrogel confinement, and proper interfacial adhesion is all essential for scalable production of the IVD.

To achieve multi-frequency vibration suppression and wave propagation modulation, eight branching ligament structures for wind models are proposed. Using lattice theory, dynamical model and finite element release method, the structures are verified to have multi-frequency bandgaps. By attaching a solid disc at the center of the model, the bandgap coverage of the structure is improved and the bandgap frequency is reduced. The modal analysis shows that the vibration of branch ligaments and border ligaments has a suppression effect on elastic waves. The phase constant surface, phase velocity and wave propagation direction plots at specific frequencies are calculated to verify the directional and regional nature of wave propagation. And the good correspondence of group velocity and wave propagation finite element simulation results at specific frequencies. Finally, the calculated bandgap frequency range is compared with the vibration transfer function, and the two agree well. And the stress cloud diagram also shows that the optimized structure has an excellent vibration suppression capability. The innovatively designed structure has the combined advantages of light weight, ease of fabrication, wide frequency and low frequency vibration control, while the integrated in-plane wave analysis provides the theoretical basis for structural optimization.

The quality of a train’s braking anti-slip control system has a significant impact on train safety and braking performance. Currently, there is no established standard evaluation method for anti-slip control systems, making it an important area of research in the academic community. This article comprehensively considers four key indexes: adhesive coefficient utilization rate, air consumption increase ratio, wheel slip work, and anti-slip valve action frequency. The evaluation system takes into account the influence of load layer and braking level, and proposes a comprehensive evaluation method for train anti-slip control based on multi-factor hierarchical analysis. A series of experiments were conducted using a semi-physical simulation test bench for anti-slip evaluation, aimed at comprehensively evaluating two different anti-slip control strategies. By applying the method proposed in this article, the above four indexes and their corresponding weights of two anti-slip control strategies under different conditions were calculated. Finally, the comprehensive evaluation result R1 of anti-slip control strategy 1 was calculated as 0.8389, while the comprehensive evaluation result R2 of anti-slip control strategy 2 was calculated as 0.7912. Based on the comprehensive evaluation results, it is evident that the anti-slip comprehensive evaluation method established in this article is comprehensive and scientific, with concise and clear evaluation results. This method carries certain reference significance for the design of future anti-slip evaluation methods.

Artificially generated datasets often exhibit biases, leading conventional deep neural networks to overfit. Typically, a weighted function adjusts sample impact during model updates using weighted loss. Meta-neural networks, trained with meta-learning principles, generalize well across tasks, acquiring generalized weights. This enables the self-generation of tailored weighted functions for data biases. However, datasets may simultaneously exhibit imbalanced classes and corrupted labels, posing a challenge for current meta-models. To address this, this paper presents Meta-Loss Reweighting Network (MLRNet) with fusion attention features. MLRNet continually evolves sample loss values, integrating them with sample features from self-attention layers in a semantic space. This enhances discriminative power for biased samples. By employing minimal unbiased meta-data for guidance, mutual optimization between the classifier and the meta-model is conducted, endowing biased samples with more reasonable weights. Experiments on English and Chinese benchmark datasets including artificial and real-world biased data show MLRNet’s superior performance under biased data conditions.

As a common interface circuit for renewable energy integrated into the power grid, the inverter is prone to work under a three-phase unbalanced weak grid. In this paper, the instability of grid-connected inverters under the unbalanced grid condition is investigated. First, a dual second-order generalized integrator phase-locked loop (DSOGI-PLL)-based inverter under balanced and unbalanced conditions is modeled. A fourth-order impedance model is established to describe its impedance characteristics under the unbalanced grid condition. To analyze this multi-input multi-output system, a simplified stability analysis method based on the generalized Nyquist stability criterion and matrix theory is proposed. Then, the influences of circuit and control parameters on the stability of the grid-connected inverter system under the unbalanced grid condition are investigated. Finally, the accuracy of the derived frequency-coupled impedance model is verified via simulations, and the effectiveness of the proposed simplified stability analysis method on the system stability analysis is verified via both simulations and hardware experiments.

Currently, there are more perfect theoretical basis and operation methods for the research of the Cu2ZnSnS4 (CZTS) solar cell characteristics, but the experimental process is tedious. In this article, to measure the characteristics of the CZTS solar cells more accurately and quickly, the computer-aided measurement method was used. During testing the characteristics of solar cells, the results were collected and analyzed by using LabCoder and Origin software. By designing experiments and using software to record data and complete solar cell characterization tests in one step, the number of artificial changes in resistance during testing is reduced. In the experiments, the data can be obtained in real time by using experimental results of computer-aided measurement technology, which can significantly improve the experimental efficiency. Through computer real-time monitoring, the maximum output power of as-prepared solar cells is P m = 1.62 W, and the calculated filling factor remains at 86%. It means that computer-aided measurement technology is suitable for the experiment of CZTS solar cell characteristics.

To illustrate the erosion mechanism of the edge aperture by high-energy ions, a three-dimension simulation model was established, and a particle-in-cell method was applied in tracking the hitting processes as well as a Monte Carlo collision method was used to deal with the particles’ collision. Numerical results showed that the potentials interacted among the sheaths of adjacent holes and the beam ions were over-focused in the accelerator gap, causing some ions to be intercepted on the downstream wall of the decelerator grid. This was a typical under-perveance characteristic of the beam current, operating at significantly less than the optimal perveance and corresponding to lower beam currents than optimal combination, which pushed the sheath to the left farther into the plasma. The farther the grid was, the more serious erosion patterns developed. In addition, the charge exchange ions were attracted and bombarded on the decelerator and the accelerator grids, respectively. The ion optics of the 30 cm ion thruster was optimized from four-zone to three-zone, where the plasma density upstream of the screen grid was increased by 1.5% and the perveance characteristics of the beam ions were improved such that many ions struck the edge hole. The background pressure was reduced from 3.0 × 10−3 to 8.0 × 10−4 Pa to decrease the erosion depths of the grids caused by the charge exchange ions, about 9.09% and two orders of magnitude, respectively, for the accelerator and decelerator grids.

Morphology engineering has been developed as one of the most widely used strategies for improving the performance of electrocatalysts. However, the harsh reaction conditions and cumbersome reaction steps during the nanomaterials synthesis still limit their industrial applications. Herein, one-dimensional (1D) novel-segmented PtTe porous nanochains (PNCs) were successfully synthesized by the template methods assisted by Pt autocatalytic reduction. The PtTe PNCs consist of consecutive mesoporous architectures that provide a large electrochemical surface area (ECSA) and abundant active sites to enhance methanol oxidation reaction (MOR). Furthermore, 1D nanostructure as a robust sustaining frame can maintain a high mass/charge transfer rate in a long-term durability test. After 2,000 cyclic voltammetry (CV) cycles, the ECSA value of PtTe PNCs remained as high as 44.47 m2·gPt–1, which was much larger than that of commercial Pt/C (3.95 m2·gPt–1). The high catalytic activity and durability of PtTe PNCs are also supported by CO stripping test and density functional theory calculation. This autocatalytic reduction-assisted synthesis provides new insights for designing efficient low-dimensional nanocatalysts.

The installation of a superlift device on the telescopic boom of a crane is the main method to improve the stress condition of the telescopic boom and to effectively improve the lifting performance of the crane. However, there is a lack of an effective and accurate numerical method to solve the critical force of a crane telescopic boom with a superlift device. Therefore, the telescopic boom with a superlift device is reasonably simplified as a stepped column and double cable model. Based on the longitudinal and transverse bending theory, the differential equations of the deflection of the n-stepped column with double cables model are established, the buckling characteristic equation and its recurrence formula of the n-stepped column with double cables model are derived, and the combined superlift equations are established. The Levenberg–Marquardt optimization algorithm is used to solve the critical force and length coefficient. A large amount of data were compared and analyzed between the numerical solution results and the ANSYS finite element simulation results. The error result analysis proved the correctness of the deduced buckling characteristic equation and its derived formula and the accuracy of the numerical solution. The numerical solution method in this paper can be used to calculate the critical force and length coefficient under any number of boom sections, boom section length, sectional moment of inertia, cable length, and included angle between the two cables of the telescopic boom with a superlift device. The numerical solution method can provide a technical support for the structural design of a telescopic boom with a superlift device in practical projects.

Aiming at the low contrast of skin lesion image and inaccurate segmentation of lesion boundary, a skin lesion segmentation method based on multi-level split receptive field and attention is proposed. Firstly, the depth feature extraction module and multi-level splitting receptive field module are used to extract image feature information; secondly, the hybrid pooling module is used to build long-term and short-term dependencies and integrate global information and local information. Finally, the reverse residual external attention module is introduced to construct the decoding part, which can mine the potential relationship between data sets and improve the network segmentation ability. Experiments on ISBI2017 and ISIC2018 data sets show that the Dice similarity coefficient and Jaccard index reach 88.67% and 91.84%, 79.25% and 81.48%, respectively, and the accuracy reaches 93.89% and 96.16%. The segmentation method is superior to the existing algorithms as a whole. Simulation experiments show that the network has a good effect on skin lesion image segmentation and provides a new method for skin disease diagnosis.

Recently, many password guessing algorithms have been proposed, seriously threatening cyber security. In this paper, we systematically review over thirty methods for password guessing published between 2016 and 2023. First, we introduce a taxonomy for classifying the existing methods into trawling guessing and targeted guessing. Second, we present an extensive benchmark dataset that can assist researchers and practitioners in successive works. Third, we conduct a bibliometric analysis to present trends in this field and cross-citation between reviewed papers. Further, we discuss the open challenges of password guessing in terms of diverse application scenarios, guessing efficiency, and the combination of traditional and deep learning methods. Finally, this review presents future research directions to guide successive research and development of password guessing.

Considering the nonlinear, time-varying, and multivariate coupling nature of the welding process, achieving excellent control of the welding process can be challenging. In addition, welding experience varies from person to person, making it difficult to establish a uniform standard. In this work, rough set theory is introduced and applied to arc welding process modeling and quality control to achieve effective online control of weld penetration during welding. A variable precision neighborhood rough-fuzzy method is proposed to enhance the efficiency and adaptability of rough set theory for information processing in the welding process. By designing welding experiments with different gaps and currents, descriptors such as the tail area coefficient and the length-width ratio of the melt pool have been proposed to characterize the melt pool. Rough set theory has been used to extract decision classification rules for welding percolation state information, and clustering analysis, fuzzy logic, and min-max fuzzy methods have been introduced for knowledge modeling. The proposed variable precision neighborhood rough-fuzzy control model is verified via three sets of experiments, and the results show that the model has excellent stability and effectiveness.

In the scenario of device-free localization under multiple effects, the accuracy of localization based on compressed sensing theory is severely affected. Most existing localization techniques directly ignore multiple path effects. However, it is not practical to ignore the multiple path effect due to its high signal strength, which can provide localization information. In this paper, we formulate the sensing matrix optimization problem in compressed sensing for device-free localization scenarios based on multiple reflections. To solve this problem, we model it as a constrained combinatorial optimization problem and propose a hybrid meta-heuristic algorithm. First, smart reflection surfaces and virtual node models are used to construct the desired communication links. Second, we iteratively improve the properties of the measurement matrix by using K-means clustering to obtain reasonable thresholds, and use a meta-heuristic algorithm to optimize the sensing matrix. Finally, the simulation results show that the proposed method efficiently optimizes the sensing matrix and achieves fast and high-precision localization while conserving communication resources.

Relativistic quantum mechanics is typically used to describe phenomena of high-energy physics but can also be applied to describe some features of quantum materials. Here, the authors use electrical circuits to simulate Dirac-like phenomena and measure Zitterbewegung and Klein tunneling for a one dimensional Bose-Hubbard model.

A high-sensitivity all-optical photoacoustic spectroscopy based on fast swept laser interferometry is proposed to trace gas detection. The momentary cavity length of the fiber-optic Fabry–Perot microphone is demodulated by a fast swept-laser interferometry with an instantaneous frequency demodulation algorithm. The all-optical photoacoustic spectroscopy based on the designed microphone was tested for trace acetylene gas detection in the near-infrared region. The normalized noise equivalent absorption coefficient for acetylene gas is achieved to be 1.06 × 10−9 cm−1 W Hz−1∕2.

This paper explores the effects of different factors on the results and accuracy of aerosol optical property measurements made in overlap factor regions using scanning lidar, simulation calculations and aerosol detection experiments. First, the measurement principle was analysed using the atmospheric layered structure model. The slope inversion of the simulated backscattering coefficient of the aerosols was performed using the Fernald method. Second, the measurement errors caused by the inhomogeneity of the horizontal atmospheric layers and scanning angle errors were analysed for different weather conditions. Finally, the aerosol detection accuracies of the scanning lidar under different weather conditions were explored by employing comparative experiments. The experimental results showed that the aerosol extinction characteristics in the overlap factor region can be effectively obtained using the proposed method and that the measurement results were affected by the systematic errors in the scanning angle. The proposed method would effectively solve the problems caused by the unavailability of optical properties of aerosols in the overlap factor region of lidar. Moreover, the signal inversion of slant detection also provides an accurate theoretical basis for field experiments and has a good aerosol detection capability and potential application prospects.

Abstract In this paper, we demonstrate the generation of high-performance entangled photon-pairs in different degrees of freedom from a single piece of fiber pigtailed periodically poled LiNbO3 (PPLN) waveguide. We utilize cascaded second-order nonlinear optical processes, i.e., second-harmonic generation (SHG) and spontaneous parametric downconversion (SPDC), to generate photon-pairs. Previously, the performance of the photon-pairs is contaminated by Raman noise photons. Here by fiber-integrating the PPLN waveguide with noise-rejecting filters, we obtain a coincidence-to-accidental ratio (CAR) higher than 52,600 with photon-pair generation and detection rate of 52.36 kHz and 3.51 kHz, respectively. Energy-time, frequency-bin, and time-bin entanglement is prepared by coherently superposing correlated two-photon states in these degrees of freedom, respectively. The energy-time entangled two-photon states achieve the maximum value of CHSH-Bell inequality of S = 2.71 ± 0.02 with two-photon interference visibility of 95.74 ± 0.86%. The frequency-bin entangled two-photon states achieve fidelity of 97.56 ± 1.79% with a spatial quantum beating visibility of 96.85 ± 2.46%. The time-bin entangled two-photon states achieve the maximum value of CHSH-Bell inequality of S = 2.60 ± 0.04 and quantum tomographic fidelity of 89.07 ± 4.35%. Our results provide a potential candidate for the quantum light source in quantum photonics.