As global plastic production increases, the problem of marine plastic pollution is becoming increasingly critical, and the development of effective identification technologies is particularly urgent as plastic debris not only poses a threat to aquatic ecosystems but also has a significant impact on human health. This paper presents the criteria for evaluating fluorescence technology and its mechanism for plastic identification, with an emphasis on its potential for the rapid detection of marine plastic pollution. By analyzing variations in the fluorescence lifetimes and intensities of plastics, different types of plastics can be effectively distinguished. In addition, this paper reviews the detection of microplastics using different fluorescent dyes and explores the fluorescence lifetime identification method. This paper also demonstrates the effectiveness of fluorescence techniques for macroplastic identification, highlighting how fluorescence lifetimes and decay rates change in various weathering environments. Monitoring these changes offers a foundation for establishing weathering models, aiding in understanding the transformation of macrolitter into microplastics. Future research should investigate the autofluorescence properties of different plastics further and focus on developing detection methods and instruments for various environments. This will improve the identification of plastic waste in complex environments. In conclusion, fluorescence technology shows great promise in plastic identification and is expected to provide substantial support for recycling plastic waste products and mitigating plastic pollution.

In order to address the requirements of scientific multidisciplinary observation in diverse small-scale regions, we have introduced the Buoy-based Cable Seafloor Observatory System (BCSOS). This system offers a distinct advantage in contexts where the use of shorter cables is feasible, contrasting with the lengthy cables typically necessary for conventional observatories. The BCSOS consists of three primary components: the Real-Time Electric Communication (RTEC) Buoy, the Power Information Transmission System (PITS), and the Seafloor Observation Subsystem (SOS). The RTEC Buoy is equipped with instruments for measuring sea surface parameters and serves as a data and power hub. The PITS, comprising a robust EM cable, connects the buoy to the SOS, which houses instruments for seafloor observations. The system is designed for a maximum water depth of 100 m and has an expected lifespan of about 5 years. The BCSOS prototypes were deployed at the Huangqi Peninsula, Fujian Province, and successfully documented the process during Typhoon Doksuri (international code 2305) at the end of July 2023. The recorded data from the BCSOS revealed a significant increase in wave height and period as the storm approached the Huangqi Peninsula. Additionally, the RTEC buoy exhibited a notable response to the large waves. The data analysis revealed a distinct pattern between the buoy response and the direction of wave propagation across various sea conditions, that the buoy’s angular movement in pitch and roll directions follows a regular elliptical distribution corresponding to different wave propagation directions. Upon thorough evaluation, future enhancements to the system are slated to concentrate on refining its design, with a particular emphasis on bolstering stability and enhancing corrosion resistance. These improvements are aimed at cementing the system’s long-term viability and performance within the challenging marine environment.

This paper proposes an offshore, unmanned auto-leveling sea-surface drifting platform, with a compact size of 0.7 m in diameter, used for obtaining air-sea interface environmental parameters. The platform was designed based on the parallel mechanism with limited degrees of freedom. The mechanical structure, control system hardware, and software of the principal prototype are introduced. A ground-based device was developed to simulate wave disturbance, based on which the static and dynamic simulation experiments were carried out. Experimental results show that the auto-leveling system can achieve real-time leveling against the angle deviation induced by waves, with a leveling accuracy of 0.2° in a simulated wave with an angle of 12°, which meets the requirements of observation equipment.

A small floating platform designed for an unmanned short-range defense system is proposed. The structures of the proposed floating platform and weapon system are detailed and described. The floating platform is investigated via virtual prototype technology in the aspects of the platform motion under sea waves of up to Beaufort wind and Douglas sea (wind-sea) scale 5. The motion equations of the floating platform are established according to the ship motion theory, and the movement of the floating platform under different wind-sea scales are simulated and analysed via multi-body fluid dynamics analysis software. To decide the proper size of the platform, the dynamic response of the floating platforms with different sizes is analysed and evaluated under various sea conditions based on multi-body dynamics. A scaled model experiment was conducted and compared with simulation results to verify the theoretical model. A verification experiment was also conducted in a water tank for the performance of the platform via simulated wave disturbance. Results show that the designed floating platform could provide a stable platform in the horizontal direction under a wind-sea scale 3 environment for the defense weapon system, which well meets the design requirement.