The growth of rubrene thin films thermally evaporated under ultra‐high vacuum (UHV) on SiO₂ has been investigated by combining atomic force microscopy (AFM), scanning electron microscopy (SEM), and polarized optical microscopy (POM) techniques. A mode of thin film growth in which an amorphous continuous holy film first covers the substrate, and acts afterwards as a template for the nucleation of polycrystalline rubrene spherulites, has been identified. Additionally, rubrene one‐dimensional structures have been observed with a catalyst‐free growth process.

This manuscript aims to optimize the acoustic scattering characteristics of underwater corner reflector linear arrays through simulation analysis and experimental validation, thereby enhancing their application efficiency in underwater acoustic countermeasures, particularly in terms of increasing acoustic echo intensity and reducing reflection blind spots. The acoustic scattering characteristics of submerged corner reflectors were meticulously simulated using the finite element method–boundary element method coupling technique, and the simulation results were rigorously verified through tank experiments. The study focused on the impact of the number of corner reflectors and their deployment angles on acoustic echo characteristics. Simulation and experimental results revealed that increasing the number of corner reflectors significantly enhances the overall target strength, with a dual corner reflector array achieving an approximately 5 decibels higher target strength than a single corner reflector. Moreover, the interaction of scattered acoustic waves among corner reflectors in the linear array generates noticeable fluctuations in the target strength curve, with these fluctuations increasing in frequency as the number of corner reflectors rises. By judiciously adjusting the deployment angles of the corner reflectors to achieve complementarity between strong and weak reflection angles, the issue of reduced target strength near 5° and 85° can be effectively mitigated, thereby significantly reducing reflection blind spots.

The underwater corner reflector is a “concave” elastic structure, and its acoustic echo exhibits large elastic loss, which affects its practical use. To study the acoustic echo elastic loss characteristics of underwater corner reflectors, based on the characteristics of small concave elastic structures of underwater corner reflectors, theoretical calculations were performed using the method of a combination of finite element and boundary element. Taking the underwater rigid corner reflector as the benchmark, the acoustic echo differences between similar types of underwater elastic corner reflectors were compared. The regular acoustic echo elastic loss of underwater corner reflectors was analyzed, and verified through pool experiments. The results show that, whether single-grid or multi-grid corner reflector, the actual acoustic echoes of underwater corner reflectors conform to the characteristics of elastic bodies, which differ significantly from rigid bodies and exhibit obvious elastic loss. The elastic loss mainly manifests as reduced target strength (TS), narrower directional pattern width, and poorer frequency stability of target strength, which is detrimental to practical use. This study provides assistance in proposing targeted methods to suppress elastic loss.