This paper presents a compact, ultra-wideband, and high-efficiency rectifier designed for microwave power transmission and energy harvesting applications. The proposed architecture integrates a series-coupled matching network with cascading band-stop structures, enabling both impedance transformation and harmonic control within a compact footprint. Two highly compact rectifiers are designed, fabricated, and measured to verify the proposed method. A broadband rectifier, operating between 1.8 and 3.0 GHz with a relative bandwidth of 50%, achieves above 70% rectification efficiency and a peak efficiency of 79%. The other wideband operation mechanism is analytically investigated: the band-stop network reshapes the diode’s impedance profile by tuning its low- and high-frequency components into a conjugate relationship, while the coupled matching structure transforms the resulting impedance to match the system impedance, thereby realizing ultra-wideband matching. The fabricated rectifier achieves a measured efficiency exceeding 40% across a wide frequency range of 1.1–3.9 GHz, corresponding to a 112% relative bandwidth at a low input power level of 0 dBm. In addition to its wideband and efficient performance, the rectifier features a highly compact form factor of only 18 × 24.8 mm2.

Odor source localization (OSL) in complex industrial environments remains a significant challenge due to the coupled effects of building occlusion and turbulent advection, which often lead to pseudo-source stagnation. This paper proposes an adaptive collaborative Genghis Khan shark optimizer (ACGKSO), a unified search framework designed for robust multi-robot OSL. Specifically, an adaptive perturbation strategy is introduced to balance global exploration and local exploitation. This is achieved through a dynamic step size mechanism driven by two factors: an exponentially decaying convergence rate and a linearly amplified term based on swarm dispersion. Concurrently, to counter premature convergence in complex environments, we introduce a dual-modal experience sharing mechanism. This approach enhances collective learning by integrating both individual historical best solutions and neighborhood optima. Experimental results validate the effectiveness and robustness of the proposed approach compared with other swarm intelligence methods. In single-interference scenarios, ACGKSO achieves a localization success rate of 94%, significantly outperforming the baseline algorithms. In more complex multi-interference environments, it maintains an 83% success rate and reduces the average number of search steps by 21.1% relative to the standard GKSO. These results demonstrate that our framework significantly outperforms other SI methods in terms of accuracy and efficiency across different environmental conditions.

This study presents an experimental investigation of the flow over a trapezoidal plate and its wake at a chord-based Reynolds number of $5800$. The plate has an aspect ratio of $1.38$ and the angle of attack varies from $4^\circ$ to $10^\circ$. Volumetric flow fields are acquired through stereoscopic particle image velocimetry and aerodynamic forces are estimated via the wake-integral approach. A key novel finding is achieved: the swallow-tailed separation bubble, characterised by a distinct concavity, enables the plate to achieve its maximum lift-to-drag ratio. This favourable performance arises from the formation of a counter-rotating vortex pair in the vicinity of the bubble concavity. This vortex pair suppresses the velocity deficit in the wake, thereby contributing to drag reduction. Overall, the swallow-tailed separation bubble structure substantially improves aerodynamic efficiency, highlighting the practical potential of spanwise fluid transport mechanism, discussed previously by Zhu et al. (J. Fluid Mech., vol. 965, 2023, p. A12), for developing effective physics-based flow control strategies.

The flow characteristics over isolated surface-mounted obstacles are investigated with time-resolved particle image velocimetry. Three different geometries (square cylinder, circular cylinder, and hemisphere) are considered maintaining the same aspect ratio of 0.5, and are completely submerged in the laminar boundary layer. The height-based Reynolds number is 1530. The time-averaged flow topologies around the three obstacles are quite similar. However, the unsteady characteristics over the square cylinder are significantly stronger than those over the circular cylinder and hemisphere. The vortices upstream of the square cylinder experience periodic amplification and decay while their cores oscillate along the flow direction. These two dynamic mechanisms corresponding to different characteristic frequencies collectively contribute to the oscillation of the entire horseshoe vortex system. Furthermore, a direct correlation between vortex number and flow pattern is established. Three categories of patterns exist in the flow field upstream of the square cylinder, corresponding to different numbers of clockwise vortices. The upstream flow field intermittently switches between these three patterns. In addition, the separation region above the square cylinder exhibits the same high-frequency characteristics as the upstream region due to the spatial oscillations of the horseshoe vortex system. Its low-frequency characteristics, however, originate from the instability of the shear layer at the free end. These findings help fill gaps in the relevant field and contribute to the study on the dynamics of the flow over surface-mounted obstacles.

Compliance with epidemic prevention norms has been found to be higher in developing regions than in developed regions; however, the nature and underlying mechanisms remain unclear. We propose that socioeconomic development of environments changes the adaptive benefits of fundamental social motives, especially disease avoidance and familial motives, which shape variations in compliance during pandemics. To examine the effects of these motives on the relationship between socioeconomic environments and compliance, we conducted three studies measuring environmental socioeconomic development with the Human Development Index (HDI). Study 1 (with two datasets: N = 43,244, 53 countries; N = 94,657, 71 countries) revealed a stable negative correlation between country-level HDI and compliance, even after controlling disease severity, government responses, and individualism. Studies 2 (an analysis of social media text data; N = 22,588, 31 provinces) and 3 (a large-sample survey; N = 6,122, 31 cities) replicated this correlation in China at the provincial and city levels, and identified disease avoidance and familial motives as mediators. These findings provide evidence for how socioeconomic environments shape compliance during pandemics, highlight the importance of familial motives alongside disease avoidance, and offer insights into tailoring public health strategies across diverse environments.

Currently, the research on the key factors which affect clinical and non-clinical pregnancy in high-quality single blastocyst transfer cycles remains relatively limited. This is particularly true for FET cycles, where the relationship between the transfer of high-quality single blastocysts and pregnancy outcomes has not been fully explored. This study aimed to identify key factors influencing clinical pregnancy outcomes in high-quality single blastocyst frozen-thawed transfer cycles to optimize assisted reproductive technology (ART). Patients under 38 years old who underwent high-quality single blastocyst frozen-thawed embryo transfer were included. Based on clinical pregnancy outcomes, they were divided into clinical pregnancy (Group A) and non-clinical pregnancy (Group B) groups. Key influencing factors were analyzed to guide the selection of blastocysts with the highest pregnancy potential.The result showed that Group B showed significantly higher age and infertility duration, but lower AMH levels, antral follicle count, and endometrial thickness on the day of transfer compared to Group A (P < 0.01). Infertility type also differed significantly (P < 0.01). Blastocyst grading differed between groups (P < 0.01), while E2, LH, P levels, embryo age, and D3 cleavage-stage cell count showed no significant differences (P > 0.05). Multivariate analysis revealed that infertility type, age, infertility duration, and endometrial thickness significantly impacted clinical pregnancy outcomes (P< 0.05), while AMH, antral follicle count, and blastocyst grading had no significant effect. All in all, clinical pregnancy outcomes are significantly influenced by age, infertility type, infertility duration, and endometrial thickness. Early treatment, optimized endometrial conditions, and selecting high-quality blastocysts are recommended to improve pregnancy rates.

Current flying-car designs lack scalability for diverse missions. This paper presents a modular design platform for developing reconfigurable flying-cars, embedding modularity across structural, electrical, and flight control domains. A full-scale sightseeing prototype demonstrates the platform’s feasibility and flexibility. The work contributes to design methodology by illustrating how modular architectures improve cross-mission adaptability, scalability, and lifecycle efficiency in complex mechatronic systems. (project introduction video available at https://www.aidilab.ai/flying-car)

This work presents an integrated modelling study of fast-proton distributions generated by ion cyclotron range of frequency (ICRF) minority heating in the Experimental Advanced Superconducting Tokamak (EAST). Using a series of high-confinement (H-mode) discharges with increasing ICRF power levels from 0.8 to 2.4 MW, fast protons were produced via minority heating mechanisms and analysed through simulations using the ASCOT code. The results reveal that the fast protons are primarily concentrated near the fundamental cyclotron resonance layer and exhibit strong power-dependent behaviour in both real-space (R–Z) distribution and velocity space, where R is the major radius and Z is the vertical coordinate. As the ICRF power increases, the energetic proton population shows significant spatial broadening and energy enhancement, reaching up to 1 MeV. The fast-ion pitch-angle distribution becomes increasingly anisotropic, with high-energy ions concentrated around $|\textit{v}_{\|}/\textit{v}| \lt 0.5$, where $\nu$ is the magnitude (speed) of the full velocity vector of the particle. Furthermore, the energy density of fast ions aligns well with the ICRF power deposition profile, confirming efficient central-core heating. These findings, which provide insight into fast-ion behaviour and ICRF heating characteristics in EAST plasmas, also support future fast-ion diagnostics and performance control strategies in EAST and similar experimental conditions.

Superswells and domes – large-scale, persistent interface deformations – are key features in geophysical and multiphase systems driven by thermal convection. These structures often emerge in layered convective systems, such as Earth’s mantle or two-fluid industrial processes, where buoyancy contrasts and fluid properties create complex interface dynamics. However, the physical mechanisms governing the formation of these structures remain poorly understood. Here, we use high-resolution direct numerical simulations of two-layer Rayleigh–Bénard convection to investigate how the Prandtl number ($\textit{Pr}$) and buoyancy number ($B$) govern transitions in interfacial morphology. At a fixed Rayleigh number ($\textit{Ra}$), we identify three distinct regimes: stratified convection at high $B$, where compositional buoyancy suppresses interfacial motion; an interfacial fragmentation regime at low $\textit{Pr}$ and $B$, driven by inertial–thermal buoyant balance; and a transitional dome-forming regime within a $\textit{Pr}$-dependent range, where viscous and buoyant forces deform the interface into coherent, superswell-like structures. A theoretical phase diagram predicts these transitions and agrees well with simulation results. These findings provide mechanistic insight into interfacial phase behaviour in thermally driven flows, offering a framework that links geophysical surface features with underlying convective dynamics and informing the control of interfacial morphology in complex multiphase systems.

Butterflies are excellent fliers in nature, flapping mode, which can ensure the completion of complex flight movements, including rapid turns, hovering, and forward and backward flights. In this paper, the Chinese yellow swallowtail (Papilio xuthus) was chosen as the bionic research subject. The flapping motion and trajectory function of P. xuthus during takeoff were obtained by the high-speed camera. On this basis, a finite element model of butterfly forewings was established, the flapping trajectory function was imported, and the transient takeoff motion of forewing was simulated by Ansys Fluent 2021R2. The aerodynamic characteristics at different angles of attack during the takeoff were obtained. The flow structure characteristics of the forewing of P. xuthus were analyzed by SIMULIA XFlow 2020. It shows that the lift and drag coefficient of the forewings during takeoff both exhibit a trend of increasing first and then decreasing as the angle of attack increases. The maximum average lift-to-drag ratio is achieved, when the angle of attack is 20°. The obtained wingtip trajectory, optimal angle of attack, and vorticity parameters can provide new design ideas for solving problems such as insufficient takeoff capability and difficult mode switching of flapping-wing microair vehicles design.

Prior research suggests that low-carbohydrate diets may reduce the frequency of headache attacks in individuals with migraine. However, the association between dietary carbohydrate intake and migraine in adults remains unclear. Given migraine’s significant public health burden and the modifiable nature of diet, understanding this relationship is vital for prevention. This study therefore investigated whether carbohydrate intake is associated with severe headache or migraine in a nationally representative sample of US adults. Using National Health and Nutrition Examination Survey (NHANES) data (1999–2004), this study examined the association between dietary carbohydrate intake and severe headache or migraine in adults aged over 20. Multivariable logistic regression was used, adjusting for demographics, socioeconomic status, lifestyle factors, and comorbidities. The study surveyed 10,413 participants, with 2062 reporting severe headache or migraine. Analysis of carbohydrate energy percentage revealed: compared to Q1 (≤42.7%), odds ratios (ORs) for severe headache or migraine were 1.04 for Q2 (42.7% to ≤50.5%, P = 0.642), 1.13 for Q3 (50.5% to ≤58.0%, P = 0.176), and 1.32 for Q4 (>58.0%, P = 0.008). A non-linear association was found between dietary carbohydrate intake and severe headache or migraine among U.S. adults (P for non-linearity = 0.002). The group with carbohydrate intake ≥51.1% of total energy had an OR of 1.22 (95% CI: 1.09–1.38, P = 0.002) compared to those below this level. The data suggest a significant association, with an important inflection point occurring at approximately 51.1%. This research uncovered a non-linear link between carbohydrate intake from diet and the chance of suffering from severe headache or migraine among American adults.

Quantifying the contribution of vortex structures to wall forces is essential for identifying the primary sources of forces. The traditional force-element method focuses on the contribution of flow structures to the resultant force. However, the contribution of flow structures to the distributed force cannot be identified. This work proposes a distributed force element method to address this issue. Inspired by the framework of matched asymptotic expansions, the method resolves the surface pressure by matching the fundamental solutions of the outer wave and inner flow regions. The pressure is thus decomposed into contributions from a convective acceleration term, a boundary acceleration term and a boundary vorticity term. The method is implemented by solving the resulting linear system with singular value decomposition. The volume source is further decomposed into direct radiation and boundary scattering components. It is found that compared with the direct radiation component, the boundary scatter component decays fast in the wake. Consequently, the direct radiation component is dominant in the far wake. A finite-domain pressure correction is proposed based on the direct radiation component. The distributed force element method is validated using several benchmark cases: two-dimensional configurations including laminar flow around stationary and oscillating circular cylinders; three-dimensional cases comprising laminar flow past a sphere, subcritical flow past a sphere and laminar flow over an inclined spheroid. The results suggest that the proposed distributed force element method enables the precise quantification of how flow structures in the wake and around the bluff bodies contribute to the surface pressure.

Direct numerical simulations of turbulence in a flexible pipe with imposed standing-wave vibration are performed to reveal the flow dynamics inside an oscillating pipe. We choose the parameters of standing-wave vibration with small amplitude as the most unstable mode in flow-induced free vibration. The flow is driven under the condition of constant mass flow rate, with the bulk Reynolds number, based on the bulk velocity and pipe diameter, being ${\textit{Re}}_b$ = 5300. In response to the imposed vibration, the evolution of the flow inside manifests obvious space–time-dependent characteristics. Specifically, the streamwise velocity fluctuation is enhanced downstream of the crest – the convex region on the internal pipe wall – an event often accompanied by localised flow separation. Meanwhile, the two other components of velocity fluctuation are augmented downstream of the trough – the concave region of the wall’s sinusoidal undulation. This is attributed to the wall deformation, which forces a redistribution of turbulent kinetic energy among the components. The latter process gives rise to a high-level fluctuation of wall shear stresses, leading to the intermittent variation of the drag force in that region. In addition, secondary flow emerges in the form of a typical counter-rotating vortex pair due to the bending of pipe, with the vortex cores located near the wall. The temporal variation of the magnitude of secondary flow lags slightly behind the pipe vibration and its maximum occurs closer to the node where the pipe displacement is consistently zero. Moreover, the secondary flow intensity increases with the increasing of steepness and a slight drag reduction can be achieved with relatively low-wavenumber vibration.