This study investigates the influence of droplet velocity on the collision behavior of equal-sized binary water droplets impacting head-on on a superhydrophobic surface. Using a high-speed camera, the dynamic process of droplet collision process was recorded, and a theoretical model was developed to describe the critical conditions governing post-collision coalescence or bouncing. The model accurately predicts the critical velocity that determines whether droplets coalesce or rebound after collision. Experimental results show that as droplet velocity increases, the probability of coalescence also increases, while larger droplet diameters correspond to lower critical velocities for the coalescence-bouncing transition. During the deformation stage of collision, internal pressure within the droplets may exceed the surface tension threshold, resulting in coalescence. The proposed theoretical model demonstrates strong agreement with experimental observations and can effectively predict droplet behavior at various velocities. This provides a theoretical basis for controlling droplet collision dynamics, with potential applications in droplet manipulation, sensing, and microreactor technologies.

In the traditional field of wireless communication, the application of long-wave communication is constrained on small and medium-sized platforms due to the requirement of large sized signal-transmitting antennas. This paper proposes and develops a three-degree-of-freedom cut-out beam structure of the vibration permanent magnet type mechanical antenna prototype based on the inverse piezoelectric effect, vibration theory, and Maxwell ’ s equations. It establishes an electric-mechanical-electromagnetic energy theory model and investigates the radiation influencing factors of the mechanical antenna along with its frequency modulation technique. The experimental results validate that electromagnetic wave signals can be frequency-modulated by exciting different vibration modes of the mechanical antenna prototype. This research offers novel theoretical and technical perspectives for low-band signal communication.

Inspired by the hydrophobic properties of the fluffs of Papaver nudicaule Linn, a multiscaled superhydrophobic structure was fabricated through a combination of 3D printing and chemical modification. The prepared structure was characterized at both micromorphological and hydrophobic levels by using scanning electron microscope and microforce instrumentation. At the macroscopic scale, the structure consists of biomimetic pillars arranged in an array on the surface, with carbon nanotube clusters adhering to the pillars to form microscopic scales. The multiscaled synergistic enhancement effect of this structure results in excellent superhydrophobicity, with a water repellency force reaching 50.68 N/m². Compared to hydrophobic coatings and other existing methods for preparing microscopic hydrophobic structures, the proposed method is economical and straightforward. The multiscaled structure exhibits strong damage resistance and stable hydrophobicity, and is conducive to industrial production. As a result, it finds applications in various fields such as directional droplet migration, fluid drag reduction, and underwater gas exchange.