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Much effort in the past few years has been made in tunnelling, however, no work has been reported so far on how to maintain the maximum tunnelling of complex optical fields in waveguides, due to the limitations of existing physical mechanisms. Here, a new paradigm is presented for realizing anomalous wave tunnelling through a general effective double‐barrier model constructed by dispersion engineering, while preserving mode information. The observed tunnelling mechanism is corroborated well by experimental results in the microwave realm. Specifically, evanescent waves bridge the gap between external space and potential well, allowing us to modulate the leaky modes within the potential well and thus achieve multiple resonant tunnelling. Due to the constant phase difference between adjacent maximum tunnelling, such mechanism broadens the potential of binary integrated devices. For example, assembling the tunnelling unit into arrays straightforwardly alleviates the trade‐off dilemma between diffraction law and cut‐off frequency. In addition, this approach provides an ideal toolbox for achieving multifunctional tunnelling across waveguide modes of various orders or polarizations, which can boost various applications in optical filters, tunneling lasers, optical switching, and sensing. [ABSTRACT FROM AUTHOR]

This study utilized particle image velocimetry (PIV) to analyze the kinematic and hydrodynamic characteristics of juvenile goldfish across three swimming modes: forward swimming, burst and coast, and turning. The results demonstrated that C-shaped turning exhibited the highest speed, enabling rapid and agile maneuvers for predator evasion. Meanwhile, forward swimming was optimal for sustained locomotion, and burst-and-coast swimming was suited for predatory behaviors. A vorticity analysis revealed that vorticity around the tail fin was the primary source of propulsive force, corroborating the correlation between vorticity magnitude and propulsion found in previous research. The findings emphasize the crucial role of the tail fin in swimming efficiency and performance. Future research should integrate ethology, biomechanics, and physiology to deepen the understanding of fish locomotion, potentially informing the design of efficient biomimetic underwater robots and contributing to fish conservation efforts. [ABSTRACT FROM AUTHOR]

The study of aquatic organisms' ectomorphology is important to understanding the mechanisms of efficient swimming and drag reduction in fish. The drag reduction mechanism in fish remains unknown yet is needed for optimising the efficiency of bionic fish. It is thus crucial to conduct drag tests and analyses. In this paper, an optimal dolphin morphological model is constructed taking the beakless porpoise as the research object. A numerical simulation of the dolphin body model is carried out for different combinations of pitch angle and speed adopting computational fluid dynamics, and the flow field noise of the dolphin body model is solved for different speeds using the FW-H equation. When the dolphin model is oriented horizontally, the differential pressure drag accounts for approximately 20–25% of the total drag as airspeed increases. As both the pitch angle and airspeed increase, the differential pressure drag and friction drag decrease with increasing airspeed. Moreover, the acoustic energy is mainly concentrated at low frequencies for both the dolphin and Bluefin-21 models. The dolphin body model has better noise performance than the Bluefin-21 model at the same speed. The optimisation of the external morphology of the bionic underwater submarine and the analysis of the shape drag are thus important for revealing the drag reduction mechanism, reducing noise in the flow field and provide guidance for research on bionic fish. [ABSTRACT FROM AUTHOR]

Visual selection plays a fundamental role in various aspects of animal behavior, such as colony formation, maintenance, defense, and courtship. This study investigated the effect of bionic robot fish color on carp behavior based on physiological characteristics that were observed during behavioral experiments. Through computer image processing and analysis of light attenuation, we observed changes in the number and positioning of carp with bionic robotic fish of different colors (white, red, blue, green, and yellow). The results indicated that (1) the attenuation coefficient of visible light in freshwater was red > yellow > green > blue; (2) the order of the average change in the number of carp responding to different colors of robotic fish was white > red > green > yellow > blue, and carp were more sensitive and responsive to white and red robotic fish; and (3) the order of the distances between different colors of robotic fish and carp was white < yellow < blue < green < red, and white and yellow robotic fish were more attractive to carp. Therefore, the use of white or yellow robotic fish for relevant operations can reduce disturbance to fish schools. [ABSTRACT FROM AUTHOR]

Simple Summary: This investigation delves into the intricate world of aquatic life, specifically zoobenthos, and how they respond to a combination of environmental challenges: climate change, eutrophication, and pesticide contamination. These organisms play a vital role in aquatic ecosystems, affecting energy flow, nutrient cycling, and sediment decomposition. Unfortunately, these challenges have led to a decline in their numbers and changes in community structure. Notably, the warmer temperatures associated with climate change promote the abundance and diversity of zoobenthos while making these communities more similar across different sites. Pesticides like imidacloprid negatively impact the survival and growth of zoobenthos. Interestingly, when combined with warming, imidacloprid seems to mitigate its adverse effects, increasing species diversity. However, when nutrient loading is part of the equation, imidacloprid negatively affects species diversity. These findings reveal the intricate responses of zoobenthos to multiple stressors, offering valuable insights for ecosystem conservation and management. In simpler terms, this study explores how tiny underwater creatures react to a changing environment, which has consequences for our ecosystems. Multiple stressors, including climate change, eutrophication, and pesticide contamination, are significant drivers of the decline in lake zoobenthos. Zoobenthos play a crucial role in aquatic ecosystems, impacting energy dynamics, nutrient cycling, and sediment degradation. However, these stressors have led to a decrease in the abundance and diversity of zoobenthos, resulting in notable changes in species composition and structure. Eutrophication typically increases zoobenthos abundance while reducing taxonomic diversity. Climate change, such as warming and heatwaves, also affects the zoobenthos community structure, with different species exhibiting varying levels of adaptability to temperature changes. Additionally, pesticides like imidacloprid have negative effects on the survival and growth of zoobenthos. However, the interactions between imidacloprid and other stressors remain understudied. Here, we used 48 mesocosms (2500 L) to simulate shallow lakes. We combined nutrient loading, sustained warming, and the imidacloprid pesticide to test how these stressors interactively influence the survival and community of zoobenthos. The experimental results demonstrate that elevated temperatures have a significant impact on aquatic benthic organisms under different treatment conditions. The increase in temperature led to a notable rise in species richness and α-diversity, primarily attributed to the stimulation of metabolic activities in zoobenthos, promoting their growth and reproduction. This finding underscores the potential influence of climate change on aquatic benthic ecosystems, particularly in terms of its promoting effect on α-diversity. However, it is essential to note that elevated temperatures also reduced β-diversity among different sites, implying a potential trend toward homogenization in zoobenthos communities under warmer conditions. Moreover, this study revealed the interactive effects of multiple stressors on the diversity of aquatic benthic communities. Specifically, the pesticide imidacloprid's impact on zoobenthos is not isolated but demonstrates complex effects within various treatment interactions. In the presence of both temperature elevation and the addition of imidacloprid, the presence of imidacloprid appears to counteract the adverse effects of temperature elevation, resulting in increased species diversity. However, when imidacloprid coincides with nutrient input, it significantly affects α-diversity negatively. These findings highlight the complexity of zoobenthos responses to multiple stressors and how these factors influence both α-diversity and β-diversity. They provide valuable insights for further research on the conservation and management of ecosystems. [ABSTRACT FROM AUTHOR]

Beam steering plays a vital role in light detection and ranging (LiDAR). However, the scanning speed is below megahertz (MHz) in current LiDAR systems. Frequency‐gradient metasurface has been reported to achieve gigahertz (GHz) beam steering with 25° scanning angle in two dimensions. However, the fabrication of millions of form‐varying nanoscale meta‐atoms poses challenges in operation efficiency, massive production, and overall cost‐effectiveness when the size goes beyond millimeter scale. Here, a dynamic beam steering comprising periodic grating nanostructures fabricated through nanoimprint lithography with an ultrafast scanning rate up to GHz (≈81 ps) and ultra‐wide three‐dimensional (3D) fields of view up to 53° × 23° is reported, which shows the powerful acquisition of 3D space data. The detection distance of object reaches to ≈230 m. This work demonstrates a wide‐angle and high‐speed beam steering, and paves a robust way to realize cost‐efficient, high‐volume manufacturing, and powerful 3D all‐solid‐state LiDAR for next‐generation intelligent vision and self‐driving technologies. [ABSTRACT FROM AUTHOR]