Results 111 to 120 of about 1,533 (215)

Heuristic algorithm-enhanced inverse design of deep-subwavelength hybrid metamaterials for ultra-broadband underwater sound absorption

Materials & Design
This study proposes a hybrid acoustic metamaterial (HAM) composed of four quasi-Helmholtz resonators (QHRs, with rubber liners and embedded necks) and one boundary-constrained viscoelastic material (BVM) arranged in parallel.
Ming Li, Fengxian Xin
doaj   +1 more source

Study on the Method of Designing Sound Absorption Model by Multiple-Layer Structures each Layer’s Natural Impedance

, 2011
The laconic calculating formulae of arbitrary multiple-layer model’s acoustic characteristics are introduced with sound transmission theoretics in multilayer mediums.
Wen Cheng Zhang, Sui Hua Zhou, An Lin Jiang   +2 more
core   +1 more source

Investigation of Acoustic Target Strength of a Cylindrical Shell Partially Covered with Anechoic Coating

水下无人系统学报
The primary structural configuration of underwater equipment consists of cylindrical shells. To study the characteristics of the acoustic target strength(TS) of a cylindrical shell partially covered with anechoic coatings, an anechoic coating with an ...
Qi MA, Shifeng NI, Hao GENG, Haibin YANG
doaj   +1 more source

Determining and testing the optimal pure-tone frequency for use in acoustic conditioning of free-ranging common carp (Cyprinus carpio)

, 2012
Pure-tone frequencies of 400, 700, and 1000 Hz were tested to determine which achieved the strongest response when used in conditioning experiments on captive common carp (Cyprinus carpio) for the purpose of determining the most effective frequency to ...
Mahoney, Brennan Andrew
core  

Dolphin-inspired target detection for sonar and radar

, 2014
Gas bubbles in the ocean are produced by breaking waves, rainfall, methane seeps, exsolution, and a range of biological processes including decomposition, photosynthesis, respiration and digestion.
Leighton, T.G., Leighton, T., White, P., White, P.R.   +3 more
core   +1 more source

Deep-subwavelength and hydrostatic-pressure-resistant meta-absorber for broadband low-frequency underwater sound

Applied Physics Express
By embedding center-supported graded-circular-plates (CS-GCPs) into an elastomer, a deep-subwavelength and hydrostatic-pressure-resistant meta-absorber was designed and manufactured for sound absorption (SA) under hydrostatic pressure.
Yanni Zhang, Manlin Tong, Xiaoting Rui, Guoping Wang, Fufeng Yang   +4 more
doaj   +1 more source

Porous AlPO4 ceramic with high strength and good acoustic performance prepared by direct foaming and gel-casting

Journal of Materials Research and Technology
Acoustic stealth of underwater vehicles demands sound insulation and decoupling materials (SIDM) with good acoustic performance, high strength, and relatively low acoustic impedance. To address this, low elastic modulus AlPO4 was selected as the backbone
Bingqing Zhao, Wei Xie, Hailong Wang, Huimin Xiang, Mingliang Li, Cheng Fang, Yanchun Zhou   +6 more
doaj   +1 more source

A characterization of underwater sound produced by heavy precipitation [PDF]

, 1990
An experiment by the Naval Postgraduate School and the National Data Buoy Center was performed in the Gulf of Mexico to investigate the underwater sound generated by heavy precipitation under a variety of conditons.
Tan, Chih-Lung
core  

Study on Sound Field Properties of Parametric Array Under the Influence of Underwater Waveguide Interface Scattering Based on Non-Paraxial Model—Theory and Experiment

Journal of Marine Science and Engineering
This paper theoretically and experimentally studies the effect of underwater waveguide interface scattering on the nonlinear sound field characteristics of parametric array (PA) radiation.
Yuan Cao, Jie Shi, Jiangyi Zhang, Yuezhu Cheng, Haokang Shi   +4 more
doaj   +1 more source

Advanced signal processing techniques for underwater acoustic transmission using steerable transducer arrays

The main objective of this research is to design and implement an eight-hydrophone transmitter array for generating bipolar acoustic pulses mimicking those produced by cosmogenic neutrino interaction in sea water.
Ooppakaew, Wichian
core