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Based on 16 years of magnetic field observations from CHAMP and Swarm satellites, this study investigates the influence of the Interplanetary Magnetic Field (IMF) Bx component on the location and peak current density of the polar electrojets (PEJs). We find that the IMF Bx displays obvious local time, seasonal, and hemispherical effects on the PEJs, as follows: (1) Compared to other local times, its influence is weakest at dawn and dusk. (2) In the midnight sectors of both hemispheres, the IMF Bx tends to amplify the westward PEJ when it is 0 in the Southern Hemisphere; this effect is relatively stronger in the local winter hemisphere. (3) At noontime, the IMF Bx intensifies the eastward current when it is 0, it reduces the westward current; this effect is notably more prominent in the local summer hemisphere. (4) Moreover, the noontime eastward current shifts towards higher latitudes, while the midnight westward current migrates towards lower latitudes when IMF Bx is 0 in the Southern Hemisphere.

Abstract Using Challenging Minisatellite Payload (CHAMP) observations, responses of ionospheric radial current (IRC) in F‐layer to sawtooth substorms in different magnetic local times are investigated. The zonal wind effect alone cannot entirely explain the variability of the substorm time disturbance IRC. When substorms commence amid stable southward interplanetary magnetic field (IMF), it induces an eastward (westward) equatorial electric field in the daytime (nighttime). This electric field induces an equatorward (poleward) Hall current at low latitudes, consequently generating an upward (downward) perturbation in IRC. Conversely, substorms with varying IMF Bz, where IMF is southward but with a reduced magnitude or turned north after the onset, induce a westward (eastward) equatorial electric field in the daytime (nighttime). This electric field induces a poleward (equatorward) Hall current at low latitudes, consequently generating a downward (upward) disturbed IRC. Notably, this effect is primarily attributed to the varying IMF Bz rather than solely to substorm onset.

BackgroundResearch has shown that gonadal hormones are involved in metabolic pathways relevant to metabolic syndrome (MetS). Nevertheless, no longitudinal study has been conducted on the association between SHBG and MetS in Chinese. The objective of our study was to determine whether there is any association between middle-aged and elderly males in China.MethodsA total of 531 eligible male subjects, aged above 40 years or older, without MetS at baseline, were recruited. Sex hormone binding globulin (SHBG), total testosterone (TT), follicle-stimulating hormone (FSH), and luteinizing hormone (LH) were measured. A harmonized definition and recommended thresholds for the Chinese population were used to determine metabolic syndrome.ResultsDuring 3.2 years of follow-up, 20.7% of subjects had developed MetS. Compared with the non-MetS group, subjects in the new-onset MetS group had significantly lower SHBG (43.5 nmol/L [28.8, 74.9] vs 53.7nmol/L [33.8, 115.0], P=0.0018), TT (18.1nmol/L [13.6–21.7] vs 19.5nmol/L[15.0–23.6], P=0.0204), and LH (5.13mIU/L [3.63–7.29] vs 5.87mIU/L [4.05–8.36]) at baseline. The incidence of MetS was decreased according to elevated SHBG quartiles (Q1:26.9%, Q2:22.7%, Q3:21.1%, Q4:12.1%, P for trend =0.0035), TT (Q1: 25.2%, Q2:23.7%, Q3: 17.3%, Q4: 16.7%, P for trend=0.0425), and LH (Q1:25.0%, Q2:21.8%, Q3: 21.8%, Q4: 14.3%, P for trend=0.0411). Compared with those in quartile 4, the OR[CI] of incident MetS for participants in Quartile 1 was 2.33[1.13–4.79] after multiple adjustments. But associations between incident MetS and different quartiles of LH, TT, and FSH were not observed after multiple adjustments. In the subgroup analyses, the significant association between SHBG level and Mets was detected in subjects over 60 years or older, with normal BMI, without insulin resistance, and with eGFR ≥90 mL/min per 1.73m2.ConclusionCompared with TT, LH, and FSH, a lower level of SHBG is significantly related to the incidence of MetS among middle-aged and elderly males in China.

This study investigates field-aligned currents (FACs) during strong magnetic storms in December 2023, analyzing variations in different local times and in the Northern (NH) and Southern Hemispheres (SH). Peak FAC densities were approximately 7.8 times higher than nominal values, with the most equatorward FACs reaching −52° magnetic latitude (MLat). In the summer hemisphere, the daytime FACs were stronger than the nighttime FACs, with the daytime westward Polar Electrojet (PEJ) surpassing nighttime levels. In the winter hemisphere, the nighttime FACs and westward PEJ were stronger than daytime. Generally, the FACs and westward PEJ were stronger in the SH than in the NH across most local time sectors, attributed to greater solar illumination. The NH pre-midnight currents were stronger than for the SH, indicating enhanced substorm currents during winter nights. The nighttime FACs occurred at lower MLat than daytime, with pre-noon FACs at a higher MLat than post-noon. The NH FACs were positioned more equatorward than their SH counterparts. In the NH, the mean FACs correlated most strongly with the merging electric field (Em) at pre-noon, post-noon, and post-midnight and with the SMU (SuperMAG Electrojet Upper Index) at pre-midnight. In the SH, the mean FACs correlated best with the SMU at pre-midnight/pre-noon, with the SML (SuperMAG Electrojet Lower Index) at post-midnight, and Em at post-noon. The mean MLat of the peak FACs show the strongest correlation with Em across most local times and hemispheres.

Hornet is a general term for insects of the genus Vespa (Hymenoptera: Vespidae). Hornets are predatory insects distributed worldwide. They often appear at apiaries in groups to prey on honey bees, and cause incalculable losses in the honey bee industry. In the face of hornet intrusion, tracking a homing hornet to find its nest is the most efficient way to discover and eliminate the hornets around an apiary. Here, five hornet-tracking methods (hornet tag tracking, triangulation, thermal imaging technology, harmonic radar, and radio telemetry) are reviewed. The advantages, disadvantages and feasibility of each method are discussed to improve the strategies for tracking hornets. Therefore, this review provides ideas for the development of hornet-tracking technology and for improving honey bee protection.

Digital twin technology significantly enhances construction site management efficiency; however, dynamically reconstructing site activities presents a considerable challenge. This study introduces a methodology that leverages camera data for the 3D reconstruction of construction site activities. The methodology was initiated using 3D scanning to meticulously reconstruct the construction scene and dynamic elements, forming a model base. It further integrates deep learning algorithms to precisely identify static and dynamic elements in obstructed environments. An enhanced semi-global block-matching algorithm was then applied to derive depth information from the imagery, facilitating accurate element localization. Finally, a near-real-time projection method was introduced that utilizes the spatial relationships among elements to dynamically incorporate models into a 3D base, enabling a multi-perspective view of site activities. Validated by simulated construction site experiments, this methodology showcased an impressive reconstruction accuracy reaching up to 95%, this underscores its significant potential in enhancing the efficiency of creating a dynamic digital twin model.

With the increasing incidence of bird damage affecting the reliability of transmission lines, addressing bird pest control has become an important task for the operation and maintenance of transmission lines. A viable solution involves the application of spray-coated polyurea elastomer composite materials to insulate exposed conductive points and weakly insulated connection parts of transmission line towers. To improve the comprehensive performance of polyurea elastomers, in this study, a polyurea curing system was modified by incorporating aluminum oxide (Al2O3), silicon dioxide (SiO2), and (boron nitride) BN nanoparticles. An orthogonal experiment was designed to investigate the influence of different fillers on the comprehensive performance of polyurea elastomers. These nanoparticles partially filled the defects inherent in the polyurea and BN microparticles, improving the alternating current (AC) breakdown strength of these elastomers. Compared with filler-free polyurea elastomers, optimal performance of the polyurea elastomers was achieved when using 5 wt% Al2O3, 0.4 wt% SiO2, and 5 wt% BN, resulting in a 15.75% increase in the AC breakdown strength and a 10.00% enhancement in the thermal conductivity.

Deoxynivalenol (DON) is a harmful fungal toxin, and its contamination in wheat flour poses a food safety concern globally. This study proposes the combination of fluorescence hyperspectral imaging (FHSI) and qualitative discrimination methods for the detection of excessive DON content in wheat flour. Wheat flour samples were prepared with varying DON concentrations through the addition of trace amounts of DON using the wet mixing method for fluorescence hyperspectral image collection. SG smoothing and normalization algorithms were applied for original spectra preprocessing. Feature band selection was carried out by applying the successive projection algorithm (SPA), uninformative variable elimination (UVE), competitive adaptive reweighted sampling (CARS), and the random frog algorithm on the fluorescence spectrum. Random forest (RF) and support vector machine (SVM) classification models were utilized to identify wheat flour samples with DON concentrations higher than 1 mg/kg. The results indicate that the SG–CARS–RF and SG–CARS–SVM models showed better performance than other models, achieving the highest recall rate of 98.95% and the highest accuracy of 97.78%, respectively. Additionally, the ROC curves demonstrated higher robustness on the RF algorithm. Deep learning algorithms were also applied to identify the samples that exceeded safety standards, and the convolutional neural network (CNN) model achieved a recognition accuracy rate of 97.78% for the test set. In conclusion, this study demonstrates the feasibility and potential of the FHSI technique in detecting DON infection in wheat flour.

Abstract Achieving satisfactory performance for a solid‐state Na‐metal battery (SSNMB) with an inorganic solid electrolyte (SE), especially under freezing temperatures, poses a challenge for stabilizing a Na‐metal anode. Herein, this challenge is addressed by utilizing a Natrium super ionic conductor (NASICON) NASICON‐type solid electrolyte, enabling the operation of a rechargeable SSNMB over a wide temperature range from −20 to 45 °C. The interfacial resistance at the Na metal/SE interface is only 0.4 Ω cm2 at 45 °C and remains below 110 Ω cm2 even at −20 °C. Remarkably, long‐term Na‐metal plating/stripping cycles lasting over 2000 h at −20 °C are achieved with minimal polarization voltages at 0.1 mA cm−2. Further analysis reveals the formation of a uniform Na3−xCaxPO4 interphase layer at the interface, which significantly contributes to the exceptional interfacial performance observed. By employing a Na3V1.5Al0.5(PO4)3 cathode, the full battery system demonstrates excellent adaptability to low temperatures, exhibiting a capacity of 80 mA h g−1 at −20 °C over 50 cycles and retaining a capacity of 108 mAh g−1 (88.5% of the capacity at 45 °C) at 0 °C over 275 cycles. This research significantly reduces the temperature threshold for SSNMB operation and paves the way toward solid‐state batteries suitable for all‐season applications.

Abstract A broadband circularly polarized (CP) dipole antenna with a backed cavity is presented in this letter. The proposed antenna consists of a pair of rotational symmetric short‐circuited branches and a Γ‐shaped feed structure. Each branch is designed to be axe‐shaped so that the antenna can achieve a broad 3‐dB axial ratio (AR) bandwidth. The coupled feeding method assures the antenna is wideband, and the shorting‐to‐the‐ground technique miniaturizes the lateral dimensions of the antenna. The profile of the proposed antenna is around 0.16λL (λL denotes the wavelength of the lower bound frequency). The introduction of a back cavity effectively enhances the boresight gain and improves the isolation level if the antenna is used to form an array. Finally, the design is prototyped, and the measurement results agree well with the simulation. The fractal voltage standing wave ratio (VSWR)

Abstract Concrete repair and rehabilitation prolong the effective service lives of structures and are important topics in the building field worldwide. Epoxy latex-modified cementitious materials have shown promise for a number of applications in building and construction, but the mix design processes remain arbitrary because their pore structures are not well understood. Porosity and pore size distributions are pore structure parameters that have direct effects on the mechanical properties and durability of concrete. In this paper, mercury intrusion porosimetry (MIP) was used to analyze the porosities and pore size distributions of epoxy latex-modified mortars. The effects of the polymer-to-cement ratio on the pore structures of epoxy latex-modified mortars were investigated. Mortars with polymer-to-cement ratios of 0%, 5%, 10%, 15%, and 20% were cured for 7, 28, 60, and 90 days in this study. Images of specimen microstructures were obtained by scanning electron microscopy (SEM), which showed that increases in the amount of epoxy latex added caused the proportion of micropores in the mortar to decrease, while the proportion of macropores and gel pores increased. The pore size distribution of epoxy latex-modified mortar was described with a composite logarithmic model. Relationships between the pore size distribution and the polymer-to-cement ratio and the curing age were obtained. The method described herein might be sufficiently accurate and convenient to evaluate or predict the pore size distribution of an epoxy latex-modified mortar, i.e., by determining the statistical distribution and analyzing the probability. The process for design of the polymer concrete mix ratio will be facilitated by methods that accurately describe the structure of the epoxy latex-modified mortar.

Robots gradually have the ability to plan grasping actions in unknown scenes by learning the manipulation of typical scenes. The grasping pose estimation method, as a kind of end-to-end method, has rapidly developed in recent years because of its good generalization. In this paper, we present a grasping pose estimation method for robots based on convolutional neural networks. In this method, a convolutional neural network model was employed, which can output the grasping success rate, approach angle, and gripper opening width for the input voxel. The grasping dataset was produced, and the model was trained in the physical simulator. A position optimization of the robotic grasping was proposed according to the distribution of the object centroid to improve the grasping success rate. An experimental platform for robot grasping was established, and 11 common everyday objects were selected for the experiments. Grasping experiments involving the eleven objects individually, multiple objects, as well as a dark environment without illumination, were performed. The results show that the method has the adaptability to grasp different geometric objects, including irregular shapes, and it is not influenced by lighting conditions. The total grasping success rate was 88.2% for the individual objects and 81.1% for the cluttered scene.

Electronegative guest‐filled skutterudites (EN‐SKDs) are considered one of the most promising thermoelectric materials for next‐generation thermoelectric generators (TEGs). However, the practical application of EN‐SKDs in TEGs is still a huge challenge because of their unsatisfactory zT value (less than 1.0). Herein, Ge, Te‐codoped electronegative sulfur‐filled skutterudites of S x Co4Sb11Ge0.2Te0.8 (x = 0, 0.05, 0.1, 0.2, 0.25) are synthesized. The optimal zT value of as high as 1.45 at 823 K with a low room‐temperature lattice thermal conductivity of 1.98 W m−1 K−1 is achieved by S0.25Co4Sb11Ge0.2Te0.8. Such performance is competitive with those of traditional TE materials and among one of the best EN‐SKDs. The excellence is attributed to the synergistic effect of the disorder caused by Ge, Te co‐doping at Sb‐site and the “rattling” effect of electronegative element S. Furthermore, a novel EN‐SKD‐based TEG is prepared for the first time through an integrated welding process and exhibits a high efficiency of 6.0% at the temperature difference of 475 K. This work provides valuable guidance for designing advanced thermoelectric materials and paves a way toward high‐performance EN‐SKD‐based TEGs.

The coupling effect of mechanical and environmental loads is the main cause of deterioration in the performance of reinforced concrete (RC) structures. However, most studies on the durability of RC structures have focused only on mechanical or environmental loads. As a result, it is difficult to fully capture the effects of dry shrinkage and creep caused by temperature and humidity changes within the structure, as well as their impact on the overall deformation of the structure. To address this gap, this paper presents a numerical simulation of underground culvert projects using the durability concrete model-complex three-dimensional (DuCOM-COM3D) analysis software. The results of the simulation demonstrate that this approach offers a more precise characterization of the porosity, temperature, and humidity inside the concrete, resulting in improved accuracy in predicting the long-term deflection, crack width, and other macro-mechanical indices of the structure. Despite these advantages, some discrepancies were observed between the calculated and measured long-term deflection values. Additionally, a limit analysis was conducted to investigate the potential causes of the large deformation observed in the measurements. Overall, the results contribute to a better understanding of the complex mechanical and environmental loads affecting RC structures and provide a methodology for accurately simulating their long-term behavior.

The hollow metal waveguides are attractive components for millimeter-wave circuits owing to low loss. To integrate with the front-end circuit, a transition from microstrip line to waveguide is required. In this article, a microstrip-to-waveguide transition is presented in the W-band by using an E-plane probe with a parasitic patch. The probe is embedded into the waveguide along the center of the broad wall to excite the TE10 mode. A backshort-circuited waveguide with a quarter wavelength is used to obtain sufficient energy coupling and achieve good impedance matching. The additional parasitic patch can introduce a new resonance at a low frequency to enhance the working bandwidth. Hence, the proposed transition achieves wide working bandwidth and low insertion loss. For verification, a back-to-back transition is constructed and measured. The measured results indicate that the proposed transition has a wide working bandwidth covering the entire W-band. The measured reflection coefficient is below −13 dB from 70 to 110 GHz and the average insert loss is 1.1 dB. Attributed to wide working bandwidth and simple structure, the proposed transition is attractive for W-band circuit systems.