Tiancong Zhao

This study presents a theoretical model for wave scattering from a multi-arc breakwater—a structure of concentric, thin-walled, and bottom-mounted arcs. The arcs can be either impermeable or porous. Using linear potential flow theory, the model employs the eigenfunction matching method and the Galerkin method to solve the hydrodynamic problem. Following convergence analysis and validation against previous data, the solution provides the excitation forces on the arcs and the surrounding wave elevation. The theoretical results show that while effective at attenuating waves, the breakwater can induce complex circumferential and radial resonances typically associated with low and high frequencies, respectively, which is a critical consideration for engineering applications.

With the advent of carbon neutrality, renewable energy installations are being upgraded toward miniaturization, low cost, and high conversion efficiency. Thus, a high output triboelectric–electromagnetic hybrid generator based on in‐phase parallel connection (IP‐HG) is proposed. The output characteristics of both TENG (triboelectric nanogenerator) and EMG (electromagnetic generator) can be effectively complemented to provide excellent output over a wide range of operating frequencies. By connecting multiple TENGs in parallel with EMGs in the same phase respectively, cumbersome rectification elements and wiring can be eliminated, and the energy output of the device can be greatly increased. The output characteristics and advantages of the IP‐HG are systematically investigated, including the material of the TENG, the rotation speed, the combination of dielectrode, and their effect on the electrical output of the IP‐HG. The short‐circuit current of 63 mA, open‐circuit voltage of 80 V, and an instantaneous output power density of 610 W m⁻³ is obtained by using a full‐wave rectifier circuit at 243 rpm, which can charge a 470 μF capacitor to 1 V in 0.2 s. A maximum output efficiency reaches 36.162% at 189 rpm. In addition, the IP‐HG can continuously power a commercial sensor and three 5 W DC light bulbs at very low rotational speeds. The reported IP‐HG offers an efficient and sustainable design approach to the development of hybrid harvesters.

The human–machine interface plays an important role in the diversified interactions between humans and machines, especially by swaping information exchange between human and machine operations. Considering the high wearable compatibility and self-powered capability, triboelectric-based interfaces have attracted increasing attention. Herein, this work developed a minimalist and stable interacting patch with the function of sensing and robot controlling based on triboelectric nanogenerator. This robust and wearable patch is composed of several flexible materials, namely polytetrafluoroethylene (PTFE), nylon, hydrogels electrode, and silicone rubber substrate. A signal-processing circuit was used in this patch to convert the sensor signal into a more stable signal (the deviation within 0.1 V), which provides a more effective method for sensing and robot control in a wireless way. Thus, the device can be used to control the movement of robots in real-time and exhibits a good stable performance. A specific algorithm was used in this patch to convert the 1D serial number into a 2D coordinate system, so that the click of the finger can be converted into a sliding track, so as to achieve the trajectory generation of a robot in a wireless way. It is believed that the device-based human–machine interaction with minimalist design has great potential in applications for contact perception, 2D control, robotics, and wearable electronics.

An acoustic wave is a type of energy that is clean and abundant but almost totally unused because of its very low density. This study investigates a novel dual‐tube Helmholtz resonator‐based triboelectric nanogenerator (HR‐TENG) for highly efficient harvesting of acoustic energy. This HR‐TENG is composed of a Helmholtz resonant cavity, a metal film with evenly distributed acoustic holes, and a dielectric soft film with one side ink‐printed for electrode. Effects of resonant cavity structure, acoustic conditions, and film tension on the HR‐TENG performance are investigated systematically. By coupling the mechanisms of triboelectric nanogenerator and acoustic propagation, a theoretical guideline is provided for improving energy output and broadening the frequency band. Specifically, the present HR‐TENG generates the maximum acoustic sensitivity per unit area of 1.23 VPa⁻¹ cm⁻² and the maximum power density per unit sound pressure of 1.82 WPa⁻¹ m⁻², which are higher than the best results from the literature by 60 and 20%, respectively. In addition, the HR‐TENG may also serve as a self‐powered acoustic sensor.

Wave energy is one of the most available energy sources in ocean. In this work, a design of high power density triboelectric nanogenerator (TENG) based on a tower structure is proposed for harvesting wave energy from arbitrary directions. Such tower-like TENG (T-TENG) consists of multiple units made of PTFE balls and 3D printed arc surface coated with melt adhesive reticulation nylon film. The power generation model coupled with the kinetic model for the T-TENG is proposed and discussed. The T-TENG can effectively convert arbitrary directional wave energy into electrical energy by utilizing charged balls rolling on optimized arc surface due to ocean wave excitation. In addition, it is found that the power density of the present T-TENG increases linearly from 1.03 W/m3 to 10.6 W/m3 by increasing the units from 1 to 10 in one block. This supports that the power density of the T-TENG increases proportionally with the number of units connected in parallel without rectifiers due to its distinctive mechanism and structure. Therefore, the design of T-TENG provides an innovative and effective approach toward large-scale blue energy harvesting by connecting more blocks to form T-TENG networks.