In breast ultrasound CT imaging, the ultrasound signals received by high-density CMUT cylindrical array have problems of low transmission efficiency, susceptibility to interference from other signals, and an inability to achieve efficient acquisition. Therefore, to overcome these problems, based on acoustic metamaterials and graphene structure, an efficient transmission model of the multi-channel breast ultrasonic signals was designed, and a finite element simulation experiment was conducted. Research showed that the separation of ultrasonic signals could be achieved by the model designed in this article. The anti-interference ability in the ultrasonic signal acquisition process was effectively improved by the good multi-channel directional transmission and the sound wave local enhancement effect, which improved the sound wave transmission efficiency. In addition, the acoustic signals could be effectively transmitted from 80 kHz to 4000 kHz, realizing broadband transmission. Based on the flexibility of the design of the phononic crystal structure, phase adjustment could be achieved in a wide frequency range by changing the parameters of the primary cell structure. This enabled the CMUT cylindrical array to obtain better directivity characteristics, laying the foundation for high-quality breast ultrasound imaging.

Cell photoacoustic detection faces the problem where the strength of the sound wave signal is so weak that it easily gets interfered by other acoustic signals. A sonic triode model based on an artificial periodic structure is designed by COMSOL Multiphysics 5.3a software (Stockholm, Sweden), and software simulations are conducted. Experiments show that when a sound wave with a specific frequency is input by the sound wave triode, it can produce an energy amplification effect on the sound wave signals of the same frequency and a blocking effect on the sound wave signals of other frequencies. This contrast effect is more obvious after increasing the sound pressure intensity of the input sound wave signal. It can effectively filter out interference sound signals. The study of the acoustic triode model provides a new approach for the acquisition and identification of acoustic signals in cell photoacoustic detection, which can significantly improve the working efficiency and accuracy of cell photoacoustic detection.

In underwater acoustic communication, there are problems of low transmission efficiency, severe loss, and inaccurate point-to-point transmission. To realize the efficient transmission of underwater acoustic communication based on finite element analysis, a metamaterial-based underwater acoustic channel model was designed using COMSOL Multiphysics 5.3 software, and its acoustic conduction mechanism was studied. It was found that the directional transmission of sound waves with low loss was achieved when the sound waves generated by the point sound source pass through the underwater acoustic channel. In addition, the periodic structure of local resonance was proposed to generate the multi-directional acoustic waves, which can control the acoustic wave transmission direction arbitrarily and improve the transmission efficiency of underwater acoustic communication. This indicates a new direction for long-distance and efficient transmission of underwater acoustic communication.

In order to analyze the characteristics of the photoacoustic signals of two identical cells at different distances, this paper conducted a finite element analysis on the influence of the parameters of the two-cell photoacoustic spectrum. The study established a two-cell model at different distances and a single cell model under the same peripheral environment. Using the two-cell model, we have obtained the frequency domain sound pressure level curves of the subject red blood cells at different angles under the influence of another cell at a different distance. In the single cell model, this paper obtains the frequency domain sound pressure level curves of a single cell at different angles when it is not affected. The frequency domain sound pressure level curve of each angle of the subject cell is compared with the frequency domain sound pressure level curve of a single cell at the same position. The results show that when the distance between the two cells is 26.6 µm, the frequency domain sound pressure level curve of the subject cell has the highest similarity with the frequency domain sound pressure level curve of a single cell. This study shows that when the distance between two cells is appropriate, the photoacoustic signals between the cells have the least influence on each other.

In order to detect the presence of melanoma cells in two cells under the condition of cell photoacoustic wave interference, this paper conducted a finite element analysis of the photoacoustic wave interference field of two cells. First, the wavelength corresponding to the dominant frequency of the signal from a single red blood cell (mean diameter) was calculated. Then, the distance between two identical red blood cells (mean diameter) was set as a multiple of the wavelength to identify the optimal interference distance and the position of the enhanced zone detection point. Next, under the optimal distance, the signal curves of two cells as red blood cells and when melanoma cells exist in two cells were calculated in sequence. Finally, the frequency domain sound pressure level curve of the detection point under the two states was compared with the single-cell signal to obtain the Frechet distance. The results show that when both cells are red blood cells, the Frechet value is less than 48; when melanoma cells exist in both cells, the Frechet value is greater than 52. This study shows that the presence of melanoma cells in two cells can be determined by adjusting the distance between the cells, arranging the positions of the detection points, and employing the Frechet distance metric curve difference under the condition that the two-cell photoacoustic waves interfere with each other.