Automatic visual localization of electric vehicle (EV) charging ports presents significant challenges in uncertain environments, such as varying surface textures, reflections, lighting and observation distance. Existing methods require extensive real-world training data and well-focused images to achieve robust and accurate localization. However, both requirements are difficult to meet under variable and unpredictable conditions. This paper proposes a 2-stage vision-based localization approach. Firstly, the image synthesis technique is used to reduce the cost of real-world data collection. A task-oriented parameterization protocol (TOPP) is proposed to optimize the quality of the synthetic images. Secondly, an autofocus and servoing strategy is proposed. A hybrid detector is employed to enhance sharpness assessment performance, while a visual servoing method based on single exponential smoothing (SES) is developed to enhance stability and efficiency during the search process. Experiments were conducted to evaluate image synthesis efficiency, detection accuracy, and servoing performance. The proposed method achieved 99% detection accuracy on the real-world port images, and guided the robot to the optimal imaging position within 16 s, outperforming comparable approaches. These results highlight its potential for robust automated charging in real-world scenarios.

The incorporation of trace metals into land snail shells may record the ambient environmental conditions, yet this potential remains largely unexplored. In this study, we analyzed modern snail shells (Cathaica sp.) collected from 16 sites across the Chinese Loess Plateau to investigate their trace metal compositions. Our results show that both the Sr/Ca and Ba/Ca ratios exhibit minimal intra-shell variability and small inter-shell variability at individual sites. A significant positive correlation is observed between the shell Sr/Ca and Ba/Ca ratios across the plateau, with higher values being recorded in the northwestern sites where less monsoonal rainfall is received. We propose that shell Sr/Ca and Ba/Ca ratios, which record the composition of soil solution, may be controlled by the Rayleigh distillation in response to prior calcite precipitation. Higher rainfall amounts may lead to a lower degree of Rayleigh distillation and thus lower shell Sr/Ca and Ba/Ca ratios. This is supported by the distinct negative correlation between summer precipitation and shell Sr/Ca and Ba/Ca ratios, enabling us to reconstruct summer precipitation amounts using the Sr/Ca and Ba/Ca ratios of Cathaica sp. shells. The potential application of these novel proxies may also be promising for other terrestrial mollusks living in the loess deposits globally.

The whitefly Bemisia tabaci (Hemiptera: Aleyrodidae) is economically one of the most threatening pests in tomato cultivation, which not only causes direct damage but also transmits many viruses. Breeding whitefly-resistant tomato varieties is a promising and environmentally friendly method to control whitefly populations in the field. Accumulating evidence from tomato and other model systems demonstrates that flavonoids contribute to plant resistance to herbivorous insects. Previously, we found that high flavonoid-producing tomato line deterred whitefly oviposition and settling behaviours, and was more resistant to whiteflies compared to the near-isogenic low flavonoid-producing tomato line. The objective of the current work is to describe in detail different aspects of the interaction between the whitefly and two tomato lines, including biochemical processes involved. Electrical penetration graph recordings showed that high flavonoid-producing tomato reduced whitefly probing and phloem-feeding efficiency. We also studied constitutive and induced plant defence responses and found that whitefly induced stronger reactive oxygen species accumulation through NADPH oxidase in high flavonoid-producing tomato than in low flavonoid-producing tomato. Moreover, whitefly feeding induced the expression of callose synthase genes and resulted in callose deposition in the sieve elements in high flavonoid-producing tomato but not in low flavonoid-producing tomato. As a consequence, whitefly feeding on high flavonoid-producing tomato significantly decreased uptake of phloem and reduced its performance when compared to low flavonoid-producing tomato. These results indicate that high flavonoid-producing tomato provides phloem-based resistance against whitefly infestation and that the breeding of such resistance in new varieties could enhance whitefly management.

Contrafreeloading (CFL) refers to animals’ tendency to prefer obtaining food through effort rather than accessing food that is freely available. Researchers have proposed various hypotheses to explain this intriguing phenomenon, but few studies have provided a comprehensive analysis of the factors influencing this behaviour. In this study, we observed the choice of alternative food containers in budgerigars (Melopsittacus undulatus) to investigate their CFL tendencies and the effects of pre-training, food deprivation, and effort required on the CFL tasks. The results showed that budgerigars did not exhibit significant difference in their first choices or the time interacting with less challenging versus more challenging food containers. Moreover, when evaluating each budgerigar’s CFL level, only half of them were identified as strong contrafreeloaders. Thus, we suggest that budgerigars exhibit an intermediate CFL level that lies somewhere between a strong tendency and the absence of such behaviour. Furthermore, we also found that food-deprived budgerigars tended to select less challenging food containers, and pre-trained budgerigars were more likely to choose highly challenging food containers than moderately challenging food containers, which means that the requirement of only a reasonable effort (access to food from moderately challenging food containers in this study) and the experience of pre-training act to enhance their CFL levels, whereas the requirement of greater effort and the experience of food deprivation act to decrease their CFL levels. Studying animal CFL can help understand why animals choose to expend effort to obtain food rather than accessing it for free, and it also has implications for setting feeding environments to enhance the animal welfare of captive and domesticated animals.

Optical fibers offer convenient access to a variety of nonlinear phenomena. However, due to their inversion symmetry, second-order nonlinear effects, such as second-harmonic generation (SHG), are challenging to achieve. Here, all-fiber in-core SHG with high beam quality is achieved in a random fiber laser (RFL). The fundamental wave (FW) is generated in the same RFL. The phase-matching condition is mainly achieved through an induced periodic electric field and the gain is enhanced through the passive spatiotemporal gain modulation and the extended fiber. The conversion needs no pretreatment and the average second-harmonic (SH) power reaches up to 10.06 mW, with a corresponding conversion efficiency greater than 0.04%. Moreover, a theoretical model is constructed to explain the mechanism and simulate the evolution of the SH and FW. Our work offers a simple method to generate higher brightness for in-fiber SHs, and may further provide new directions for research on all-fiber χ(2)-based nonlinear fiber optics and RFLs.

The dynamics of small-scale structures in free-surface turbulence is crucial to large-scale phenomena in natural and industrial environments. Here, we conduct experiments on the quasi-flat free surface of a zero-mean-flow turbulent water tank over the Reynolds number range $Re_{\lambda } = 207$–312. By seeding microscopic floating particles at high concentrations, the fine scales of the flow and the velocity-gradient tensor are resolved. A kinematic relation is derived expressing the contribution of surface divergence and vorticity to the dissipation rate. The probability density functions of divergence, vorticity and strain rate collapse once normalised by the Kolmogorov scales. Their magnitude displays strong intermittency and follows chi-square distributions with power-law tails at small values. The topology of high-intensity events and two-point statistics indicate that the surface divergence is characterised by dissipative spatial and temporal scales, while the high-vorticity and high-strain-rate regions are larger, long-lived, concurrent and elongated. The second-order velocity structure functions obey the classic Kolmogorov scaling in the inertial range when the dissipation rate on the surface is considered, with a different numerical constant than in three-dimensional turbulence. The cross-correlation among divergence, vorticity and strain rate indicates that the surface-attached vortices are strengthened during downwellings and diffuse when those dissipate. Sources (sinks) in the surface velocity fields are associated with strong (weak) surface-parallel stretching and compression along perpendicular directions. The floating particles cluster over spatial and temporal scales larger than those of the sinks. These results demonstrate that, compared with three-dimensional turbulence, in free-surface turbulence the energetic scales leave a stronger imprint on the small-scale quantities.

We studied flow organization and heat transfer properties in mixed turbulent convection within Poiseuille–Rayleigh–Bénard channels subjected to temporally modulated sinusoidal wall temperatures. Three-dimensional direct numerical simulations were performed for Rayleigh numbers in the range $10^6 \leqslant Ra \leqslant 10^8$, a Prandtl number $Pr = 0.71$ and a bulk Reynolds number $Re_b \approx 5623$. We found that high-frequency wall temperature oscillations had minimal impact on flow structures, while low-frequency oscillations induced adaptive changes, forming stable stratified layers during cooling. Proper orthogonal decomposition (POD) analysis revealed a dominant streamwise unidirectional shear flow mode. Large-scale rolls oriented in the streamwise direction appeared as higher POD modes and were significantly influenced by lower-frequency wall temperature variations. Long-time-averaged statistics showed that the Nusselt number increased with decreasing frequency by up to 96 %, while the friction coefficient varied by less than 15 %. High-frequency modulation predominantly influenced near-wall regions, enhancing convective effects, whereas low frequencies reduced these effects via stable stratified layer formation. Phase-averaged statistics showed that high-frequency modulation resulted in phase-stable streamwise velocity and temperature profiles, while low-frequency modulation caused significant variations due to weakened turbulence. Turbulent kinetic energy (TKE) profiles remained high near the wall during both heating and cooling at high frequency, but decreased during cooling at low frequencies. A TKE budget analysis revealed that during heating, TKE production was dominated by shear near the wall and by buoyancy in the bulk region; while during cooling, the production, distribution and dissipation of TKE were all nearly zero.

Xiangranggounan is an intensively occupied settlement associated with the Kayue culture on the north-eastern Qinghai-Tibet Plateau. Excavations in 2022 and 2023 revealed five house types with clear stratigraphic relationships that help to expand current understanding of the evolution of prehistoric settlement patterns in harsh plateau environments.

This paper introduces a three-substrate layered transmitarray design that avoids the use of vias, aiming to produce broadband orbital angular momentum (OAM) vortex beams within the Ka-band. The suggested element configuration accomplishes a full 360∘ transmission phase while upholding a 1-dB transmission loss, with an overall thickness measuring 3.4 mm (equivalent to 0.34λ0 at 30.0 GHz). Its balanced unit cell arrangement amplifies its effectiveness in applications involving dual polarization. We examine the transmitarray behavior across four OAM modes (+1, +2, +3, +4 ), unveiling notable mode purity at operating frequency. Specifically, a broadband OAM vortex beam is achieved for the +1 mode during simulation. A square aperture transmitarray fed by a horn antenna is fabricated and measured to validate these simulated findings. Experimental results confirm the successful broadband vortex beam generation for $l = +1$ mode across the frequency spectrum from 27.0 to 40.0 GHz, approximately 43.3%. Additionally, the proposed transmitarray achieves a peak gain of 21.7 dBi, accompanied by an 11.8% aperture efficiency. Noteworthy is the consistent maintenance of mode purity above 86%.

To address the challenges of high-manoeuver targets and limited line-of-sight from the interceptor’s side window, this paper proposes a three-dimensional target manoeuver compensation control (TMCC) guidance law based on compensation function observe (CFO) and a method for studying the terminal guidance handover region. First, a relative model of the missile-target engagement is established. Secondly, the CFO is used to estimate the target manoeuver state, and the estimated information is fed back to the controller of the orbit control engine to make the interception more accurate. Considering the limited line of sight of the side window, the body line of sight angle is constrained by controlling the attitude control engine. Then, the problem description for solving the handover area and the definition of the terminal guidance handover area were provided, and the algorithm design for the handover area was conducted, simplifying the solving process through the concept of area substitution. Simulation results indicate that the proposed terminal guidance law offers higher interception accuracy compared to traditional proportional guidance, and effectively validates the accuracy of the handover region calculation.

In this paper, a large, compact array antenna that can be expanded in the 2-D plane is proposed for near-field radio frequency identification applications. By the introduction of the fractal structure and corner joint method, the array is easy to expand in the 2-D plane. An antenna element can be divided into a dozen or so loops, and traveling wave distribution makes sure that every loop is excited in a time period. So that a strong and uniform magnetic field could be generated in a large area. As a proof of concept, array antennas with $1 \times 8$, $2 \times 4$, and $3 \times 3$ elements are designed, fabricated, and measured. The measured bandwidth of the antennas covers the entire Chinese standard. Reading distances of the proposed large array antennas achieved up to 57 mm. Results show that the proposed antenna could realize flexibility and extendibility in a large area with stable and uniform magnetic field distribution.

Conservation agriculture (CA), as a key component of sustainable intensification, has been widely promoted across sub-Saharan Africa (SSA) to address low crop productivity. However, the focus has mainly been on improving cereal grain yields, with less focus to its impact on nutritional outcomes. This study sought to assess the productivity potential of CA crop diversification systems and associated crop establishment techniques in terms of grain, protein, and energy yields. An on-station trial was implemented in Malawi for four cropping seasons (2014/15 to 2017/18). Four crop establishment techniques (ridge and furrow, jab planter, dibble sticks, and CA basins) were tested, while cropping systems included conventional cropping system (Conv), CA sole cropping (CaSole), CA intercropping (CA-intercropping), and CA rotations (CA-rotation). In 2014/15 and 2015/16 cropping seasons, characterised by medium and low rainfall, respectively, planting basins and ridge-furrow systems produced higher maize yields compared to jab planter and dibble stick systems. In 2015/16, big and small basins yielded 5061 and 3969 kg ha–1, while jab planter and dibble stick yielded 3476 and 3213 kg ha–1. When there was high and persistent rainfall (2016/17 and 2017/18), direct seeding (jab planter and dibble stick) outperformed basins and ridge-furrow systems. Therefore, the choice of planting basin sizes and whether or not to use dibble stick and jab planter needs to be guided by location or site-specific seasonal forecasts for best results. Grain yield in maize-legume rotation systems consistently outperformed other systems, with maize-groundnut rotations surpassing maize-cowpea intercrops by 987–2700 kg ha–1 over four cropping seasons. In intercropping systems, maize-pigeon pea outperformed maize-cowpea by 4–45% during the same period, while maize-cowpea rotation consistently out yielded maize-cowpea intercropping. Intercropping systems, however, provided substantial protein benefits, with maize-pigeon yielding +9.5% (2015/2016), +29.1% (2016/2017) over CA sole, and +2.2% (2017/2018) over cowpea intercropping. Sole systems (conventional and CA sole) yielded the highest caloric energy, while maize-cowpea rotation consistently reduced energy yield by 35% to 54% compared to the highest-yielding systems. Overall intercropping systems can outperform rotation systems in nutritional security but when focus is on maize grain yield alone, intercropping may reduce maize yield when compared to both cereal sole and maize-legume rotation systems.

On the Experimental Advanced Superconducting Tokamak (EAST), the electron cyclotron wave (ECW) and lower hybrid wave (LHW) are actively used to achieve a high-performance plasma. Turbulence associated with the combined heating experiment is studied numerically based on the gyrokinetic toroidal code (GTC). The linear simulation results show that the unstable mode peaks at $k_{\theta }\rho _{s}\approx 0.65$ and $k_{\theta }\rho _{s}\approx 1.42$. Meanwhile, all of the frequencies of these instabilities are positive, which suggests that the collisionless trapped electron mode (CTEM) is the dominant instability. In the process of nonlinear simulations, a higher transport level is locally achieved during the two waves combined heating due to a formation of a steeper electron temperature gradient. In addition, a low-frequency geodesic acoustic mode (GAM) is observed in the nonlinear stage. Effects of the electron beta, the dimensionless ratio of $T_e/T_i$ and $R/L_{T_e}$ on the growth rate of instability, are also discussed in the paper.