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In the acoustic signal receiving section of underwater vehicle, an effective measure to improve surface acoustic impedance and reduce signal attenuation is to cover acoustic barrier plate of hydrophone array with high impedance material (signal conditioning plate). Compared with traditional full coverage mode, an acoustic grating (periodic installation of regulator plate array) can greatly improve the received signal gain and reduce the weight of the receiving segment. In order to deeply understand the signal enhancement mechanism and optimize the design of acoustic grating, the factors that influence the signal enhancement performance of acoustic grating from the aspects of width, thickness, incident angle and structure width ratio is studied. Simulation results show that the oblique incidence will change the symmetrical distribution of signal ratio (SR), but will not significantly change the acoustic performance of the structure. Wider and thicker regulating plate lead to stronger non-mirror scattering and better signal enhancement performance of structure. In practical application, geometric parameters of acoustic grating should be reasonably designed to meet multiple constraints of real environment to achieve optimal overall performance. In addition, the moderate width ratio can obtain a good overall acoustic performance.

The performance of an Unmanned Underwater Vehicle (UUV) is significantly influenced by the magnitude of self-generated noise, making it a crucial factor in advancing acoustic load technologies. Effective noise management, through the identification and separation of various self-noise types, is essential for enhancing a UUV's reception capabilities. This paper concentrates on the development of UUV self-noise separation techniques, with a particular emphasis on feature extraction and separation in multi-task learning environments. We introduce an enhancement module designed to leverage noise categorization for improved network efficiency. Furthermore, we propose a neural network-based multi-task framework for the identification and separation of self-noise, the efficacy of which is substantiated by experimental trials conducted in a lake setting. The results demonstrate that our network outperforms the Conv-tasnet baseline, achieving a 0.99 dB increase in Signal-to-Interference-plus-Noise Ratio (SINR) and a 0.05 enhancement in the recognized energy ratio. [ABSTRACT FROM AUTHOR]

Textured relaxor-PbTiO3 ceramics have received considerable attention from both academia and industry, due to their crystal-like properties, high composition homogeneity easy-to-process, and relatively low cost compared to their crystal counterparts. In this work, the ⟨ 001 ⟩ -oriented Pb(In1/2Nb1/2)O3-Pb(Sc1/2Nb1/2)O3-PbTiO3 textured ceramics were fabricated by the template grain growth method. To explore the property variation in these textured ceramics under practical applications of piezoelectric devices, their electromechanical properties were characterized and analyzed under uniaxial stress, hydrostatic pressure, and d.c. bias electric field. The results show that the dielectric constants of all textured ceramics increase with an increase in the uniaxial prestress and hydrostatic pressure but decrease with an increase in the d.c. bias electric field. Among all textured ceramics, the textured ceramic with 3 vol. % BT templates exhibits the best stability under external fields. In particular, the electromechanical coupling factors of the textured ceramic change less than 2% with the hydrostatic pressure increase to 100 MPa. This work provides important data on textured relaxor ferroelectric ceramics, which will benefit the design and application of piezoelectric devices based on textured piezoelectric ceramics. [ABSTRACT FROM AUTHOR]

True morels (Morchella) are globally renowned medicinal and edible mushrooms. White mold disease caused by fungi is the main disease of Morchella, which has the characteristics of wide incidence and strong destructiveness. The disparities observed in the isolation rates of different pathogens indicate their varying degrees of host adaptability and competitive survival abilities. In order to elucidate its potential mechanism, this study, the pathogen of white mold disease from Dafang county, Guizhou Province was isolated and purified, identified as Pseudodiploöspora longispora by morphological, molecular biological and pathogenicity tests. Furthermore, high-quality genome of P. longisporus (40.846 Mb) was assembled N50 of 3.09 Mb, predicts 7381 protein-coding genes. Phylogenetic analysis of single-copy homologous genes showed that P. longispora and Zelopaecilomyces penicillatus have the closest evolutionary relationship, diverging into two branches approximately 50 (44.3–61.4) MYA. Additionally, compared with the other two pathogens causing Morchella disease, Z. penicillatus and Cladobotryum protrusum, it was found that they had similar proportions of carbohydrate enzyme types and encoded abundant cell wall degrading enzymes, such as chitinase and glucanase, indicating their important role in disease development. Moreover, the secondary metabolite gene clusters of P. longispora and Z. penicillatus show a high degree of similarity to leucinostatin A and leucinostatin B (peptaibols). Furthermore, a gene cluster with synthetic toxic substance Ochratoxin A was also identified in P. longispora and C. protrusum, indicating that they may pose a potential threat to food safety. This study provides valuable insights into the genome of P. longispora, contributing to pathogenicity research. [ABSTRACT FROM AUTHOR]

The coalbed methane (CBM) productivity is directly determined by the fracture permeability during hydraulic fracturing, which is regulated by the distribution of proppants. The proppant may be unevenly distributed in the fracture because of variables like the architecture of the fracture and the characteristics of the sand‐carrying fluid. This study used two types of random functions to produce different ununiform distributions of proppant clusters in large‐scale fractures, with the aim of investigating the effect of these distributions on the overall permeability of the fracture. A model of fluid‐structure coupling is proposed. The closure of large‐scale fractures under in‐situ stress is analyzed using solid mechanics and the penalty function; the CBM flowing in proppant clusters and the high‐speed channel between them is simulated using Darcy's law and the Navier–Stokes equation, respectively; and the overall permeability of fractures is computed using the fluid pressure drop throughout the fracture and the fluid flowing velocity in the fracture's outlet. Since most CBM flows along high‐speed channels between the proppant clusters, the simulated findings show that the overall permeability of fractures with an uneven distribution of proppant clusters is significantly higher than that of the proppant cluster itself. As CBM becomes more discretely distributed, the proportion of CBM flowing within the proppant cluster continuously drops. As the permeability of the proppant cluster increases, the volume ratio of proppant clusters decreases, and the distribution of proppant clusters becomes more discrete, the overall permeability of the fracture continuously increases. [ABSTRACT FROM AUTHOR]