Theoretical model on underwater sound detection based on laser heterodyne method

Author(s):  
Jing Li ◽  
Xiaodong Zeng ◽  
Changqing Cao ◽  
Zhejun Feng
1989 ◽  
Vol 14 (20) ◽  
pp. 1152 ◽  
Author(s):  
Kjell Kråkenes ◽  
Kjell Bløtekjaer

2009 ◽  
Vol 610-613 ◽  
pp. 567-572
Author(s):  
Kai Rui Zhang ◽  
Qiu Zhu Li ◽  
Guo Wen Liu ◽  
Xiao Jun Shi

A new method for the MEMS die package process was reported. Using the method of bionic package, a novel MEMS vector hydrophone was fabricated from a typical mass-beam accelerometer structure. According to the auditory principle of fish’s lateral line and its nature’s fundamental acoustic sensors-stereocilia, a rigidity cylinder was fixed on the center of the mass as a stereocilia, and the sensitivity structure of the hydrophone was obtained. By means of a specific package process, the sensor was fabricated properly for the underwater sound detection application. From the test results of the sensor, we can see that, this vector hydrophone has a receiving sensitivity of -165dB (0dB=1V/µPa, the amplification factor of the preamplifier is 100.) and a good directional pattern in form of “8”-shape. The hydrophone can work well under the maximum pressure of 2MPa.


2018 ◽  
Vol 8 (2) ◽  
pp. 25-39
Author(s):  
Mohamed Elhadi Rahmani ◽  
Abdelmalek Amine ◽  
Reda Mohamed Hamou

Sound Navigation and Ranging (Sonar) is underwater sound detection used in boats or submarines to navigate, communicate with or detect objects under the surface of water based on sound propagation. It is helpful for exploring and mapping the ocean because sound waves travel farther in the water than do radar and light waves. Based on signal data obtained from sonar, this article presents a new heuristic approach inspired from black holes' phenomenon proposed by Schwarzschild, it has been applied to the classification sonar returns from two undersea targets, a metal cylinder and a similarly-shaped rock. Results are very satisfied (almost 83% of accuracy) compared to original works. in manner that encourage to keep working on paper, the main idea of this article is to benefit from the power of nature to solve complex problems in computer science


2001 ◽  
Vol 40 (21) ◽  
pp. 3502 ◽  
Author(s):  
M. Volkan Ötügen ◽  
Biswa Ganguly

1999 ◽  
Vol 77 (11) ◽  
pp. 1751-1758 ◽  
Author(s):  
D Kastak ◽  
R J Schusterman

In-air and underwater sound detection thresholds were obtained for a female northern elephant seal (Mirounga angustirostris). Hearing sensitivity in air was generally poor, but was best for frequencies between 3.2 and 15 kHz, and showed greatest sensitivity at 6.3 kHz (43 dB re: 20 µPa). The upper frequency limit in air was approximately 20 kHz. The underwater audiogram is similar to those obtained from other phocids in that sensitivity was best between 3.2 and 45 kHz, with greatest sensitivity at 6.4 kHz (58 dB re: 1 µPa) and an upper frequency cutoff of approximately 55 kHz. The elephant seal was more sensitive to low frequencies (<1 kHz) than other pinnipeds tested. Thresholds obtained in water were lower than those obtained in air (19 dB in terms of sound pressure, 52 dB in terms of sound intensity), indicating that the elephant seal is adapted for underwater hearing. The outer and middle ears of the elephant seal are modified relative to those of other phocids. These modifications are probably needed to cope with extreme static pressures related to deep diving, and are likely to confer relatively good auditory sensitivity under water.


Author(s):  
C.A. Radford ◽  
K. Tay ◽  
M.L. Goeritz

Sound perception and detection in decapod crustaceans is surprisingly poorly understood, even though there is mounting evidence for sound playing a critical role in many life history strategies. The suspected primary organ of sound perception are the paired statocysts at the base of the first antennal segment. To better understand the comparative sound detection of decapods, auditory evoked potentials were recorded from the statocyst nerve region of four species (Leptograpsus variegate, Plagusia chabrus, Ovalipes catharus, Austrohelice crassa) in response to two different auditory stimuli presentation methods, shaker table (particle acceleration) and underwater speaker (particle acceleration and pressure). The results showed that there was significant variation in the sound detection abilities between all four species. However, exposure to the speaker stimuli increased all four species sound detection abilities, both in terms of frequency bandwidth and sensitivity, compared to shaker table derived sound detection abilities. This indicates that there is another sensory mechanism in play as well as the statocyst system. Overall, the present research provides comparative evidence of sound detection in decapods and indicates underwater sound detection in this animal group was even more complex than previously thought.


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