The Experts below are selected from a list of 9090 Experts worldwide ranked by ideXlab platform
Guo-jun Zhang - One of the best experts on this subject based on the ideXlab platform.
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Design and analysis of a multiple sensor units vector hydrophone
AIP Publishing LLC, 2018Co-Authors: Xiaoyong Zhang, Guo-jun Zhang, Nixing Shen, Zhenzhen Shang, Yu Pei, Junwen Ding, Lansheng Zhang, Renxin Wang, Wen Dong ZhangAbstract:Inspired by the hairy structure of fish neuromast, a multiple sensor units (multi-unit) vector hydrophone is proposed in the paper, which integrates multiple sensor units on one chip according to bionics. Its sensitivity and signal noise ratio (SNR) are theoretically analyzed compared with the hydrophone which has only one sensor unit. In order to verify the correctness of the theory, a 4-unit vector hydrophone has been fabricated. For experiments, the comparative calibration experiment is used to validate the theoretical analysis of sensitivity and fast fourier transform algorithm (FFT) is used to process the experiment data to verify the theoretical analysis of SNR. The results show that the sensitivity of the 4-unit hydrophone is improved by 11.8 dB and the SNR is improved by 1.9 dB on average, which is correlated with the theoretical analysis
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Design and Experiment Research on MEMS Vector Hydrophone Vibration Damping Structure
2016Co-Authors: Nan Guo, Guo-jun Zhang, Wen Dong ZhangAbstract:structure Abstract: A novel vibration damping structure is designed based on the existing package structure of MEMS vector hydrophone. It is desirable that this novel structure can isolate the vibration noise caused by working platform so as to improve the anti-noise ability of hydrophone. This novel structure is made of “dow corning ” damping silicone rubber which is manufactured with a certain proportion because of its small Young’s Modulus. The hydrophone is fabricated in the form of original packaging structure firstly and then in vibration-isolation packaging structure. Laboratory tests by means of the shaking table test and standing-wave tube test are performed to validate the theoretical results. The test results prove that the vibration damping structure can effectively isolate the interference signal produced by working platform without affecting the sensitivity of hydrophone obviously. 1
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orange peel encapsulating structure for bionic vector hydrophone of micro electro mechanical system
2012Co-Authors: Guo-jun Zhang, Changde He, Linxian Liu, Jijun Xiong, Zhen Li, Hui Zhang, Chenyang XueAbstract:The invention relates to an orange-peel encapsulating structure for a bionic vector hydrophone of a micro-electro-mechanical system. Different performance indexes of the hydrophone can be further improved through the orange-peel encapsulating structure. The orange-peel encapsulating structure comprises a support pipe, wherein the top part of the support pipe is provided with a necked-in tubule, the top part of the necked-in tubule is provided with a support disc, the edge of the support disc is provided with a ring-shaped clamping groove, the inside of the ring-shaped clamping groove is fixedly connected with a sound transmission cap, a bottom orifice of the support pipe is provided with a choke plug and a locking nut, a support platform which is fixedly arranged on the support disc, and an orange-peel metal bracket which is threadedly connected onto the support platform are also arranged inside the sound transmission cap, a flexible bracket for holding a four-beam-ciliary-type sensitive body is clamped between the support platform and the orange-peel metal bracket, and the sound transmission cap, the orange-peel metal bracket, the four-beam-ciliary-type sensitive body, the flexible bracket and the support platform are closely and seamlessly combined with one another. Compared with the hydrophone adopting the existing encapsulating structure, the resonance frequency of the hydrophone adopting the orange-peel encapsulating structure can be improved by about three times, the sensitivity can be improved by 20dB, and the reliability and the shock resistance of the hydrophone can also be obviously improved.
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Design of a Novel MEMS Resonant-Column Type Bionic Vector Hydrophone
2012 International Conference on Computing Measurement Control and Sensor Network, 2012Co-Authors: Guo-jun Zhang, Guiying Chen, Wen Dong ZhangAbstract:A Resonant-column Type Vector Hydrophone based on MEMS technology and bionic principle was presented, which consists of two-dimensional bionic hydrophone and pressure hydrophone. Based on acoustic theory, the design and manufacture of the vector hydrophone are described. Preliminary characterization calibration of the hydrophone were performed in National Defense Underwater Acoustics Calibration Laboratory of China. Results show that working frequency band is 0-3KHz, X-channel sensitivity is -177.9dB (2KHz), Y-channel sensitivity is -175.4dB (2KHz), pressure channel sensitivity is -175.8dB (2KHz); And the Resonant-column Type Bionic Vector hydrophone not only possesses good "8" directional pattern but also can withstand 3MPa pressure. The application of this novel MEMS Resonant-column Type Bionic vector hydrophone is broad, from civil ships' evading bonds, fishery to hydrospace detection.
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three dimensional vector hydrophone
2011Co-Authors: Guo-jun Zhang, Changde He, Linggang Guan, Jijun Xiong, Yuhua Yang, Guixiong Shi, Jiao Xu, Xiaoyao WangAbstract:The invention relates to a vector hydrophone in the field of micro-electro-mechanical system (MEMS) sensors, in particular to a three-dimensional vector hydrophone, and solves the problems that the conventional combined three-dimensional vector hydrophone is unfavorable for realizing miniaturization, is difficult to produce in batches, and the like. The hydrophone comprises sensing units for sensing underwater acoustic signals in an X direction, a Y direction and a Z direction respectively, wherein the sensing unit for sensing the underwater acoustic signal in the Z direction comprises a semiconductor frame and two cantilever beams which are suspended in the semiconductor frame, are parallelly arranged and have equal length; single ends of the cantilever beams are fixed with the same border of the semiconductor frame, and free ends of the cantilever beams are fixed together through a connecting beam; the ends of the two cantilever beams fixed with the semiconductor frame are provided with a strain sensing element respectively; two reference sensing elements are arranged on the semiconductor frame and are connected to form a bridge circuit; and the semiconductor frames of the two sensing units are integrated on the same plane. The hydrophone has a simple and novel structure, is monolithically integrated, is easy to miniaturize, manufacture and produce in batches, and has a wide application range.
K C Tam - One of the best experts on this subject based on the ideXlab platform.
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rheological properties of a telechelic associative polymer in the presence of alpha and methylated beta cyclodextrins
Journal of Physical Chemistry B, 2007Co-Authors: Dongsheng Liao, Sheng Dai, K C TamAbstract:The viscosity of hydrophobic ethoxylated urethane (HEUR) solution decreased in the presence of alpha-CD or m-beta-CD; however their interactions were quite different. When the alpha-CD/Hydrophobe molar ratio exceeded 5.0, the viscosity was close to that of a PEO solution of similar molecular weight. Oscillatory shear indicated that the mechanically active chains in HEUR solution decreased with the addition of alpha-CD. This agreed with the hypothesis that alpha-CD formed an inclusion complex with the hydrophobic moiety of the HEUR polymer, thereby destroying the transient hydrophobic associative network. The viscosity/temperature relationship of the alpha-CD/HEUR system (for HEUR with 70% of the PEO chains capped at both ends) did not obey the Arrhenius relationship for alpha-CD/Hydrophobe molar ratio in the range 0.8-5.0. The low shear viscosity increased with increasing temperature at molar ratio of 1.0, and this was attributed to the competitive complexation of the alpha-CD/Hydrophobe and the alpha-CD/PEO chain. Increasing temperature favored alpha-CD/PEO complexation. Comparison between the behavior of alpha-CD/HEUR and m-beta-CD/HEUR resulting from the different binding characteristics was discussed.
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rheological properties of hydrophobically modified alkali soluble polymers effects of ethylene oxide chain length
Journal of Polymer Science Part B, 1998Co-Authors: K C Tam, R D Jenkins, M L Farmer, D R BassettAbstract:The rheological properties of hydrophobic alkali-soluble associative polymers (HASE) were studied using controlled rate (Mettler LS40) and controlled stress (TA CSL 500) rheometers. The effects of pH and polymer concentrations on the rheological properties of three HASE model polymer systems (i.e., HASE 5141, 5134, and 5142, with a degree of ethoxylation of 2.5, 10, and 40 mol, respectively) and a reference polymer without associative Hydrophobes (MAAEA) were examined. As the pH is increased by addition of ammonia to greater than 5–6, the carboxyl groups ionize to carboxylate ions and the polymers become water soluble. The HASE polymers thicken mainly by hydrophobic association. Viscosity can increase by two to three orders of magnitude as pH is raised to 9. The degree of ethoxylation in the macromonomer controls the nature of the hydrophobic association junctions by altering the flexibility and hydrophobicity of the macromonomer. Optimum thickening efficiency is observed in the system with approximately 10 mol of an ethylene–oxide spacer between the polymer backbone and the macromonomer. Viscoelastic study shows that the maximum thickening efficiency also corresponds to the dominant elastic property observed in the system with 10 mol of EO. All the model systems except the control system without Hydrophobe exhibit strain thickening of the viscous and elastic components. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2275–2290, 1998
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rheological properties of model alkali soluble associative hase polymers effect of varying Hydrophobe chain length
Macromolecules, 1997Co-Authors: V Tirtaatmadja, K C Tam, R D JenkinsAbstract:The rheological properties of 1 wt % aqueous solutions (at pH between 8.7 and 9.5) of model associative (HASE) polymers are presented. These polymers are the polymerization product of methacrylic acid, ethyl acrylate, and macromonomers which contain Hydrophobes with the alkyl chain ranging in length from C12 to C20. At high pH, the polymers form a network of temporarily associating hydrophobic junctions, resulting in an enhancement of the shear viscosity which increases with the Hydrophobe chain length. Strain amplitude sweep results show that the strength of the hydrophobic association increases with the length of the Hydrophobe. This is also reflected in the increase in the ratio of the elastic to viscous components of the linear viscoelastic properties. When sheared beyond its equilibrium state, the associative polymers display a terminal (second-order) viscoelastic behavior at higher frequencies as the network is increasingly being disrupted by higher applied stresses. The general behavior of the poly...
John Van Velzen - One of the best experts on this subject based on the ideXlab platform.
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towards a high performance fiber laser hydrophone
Journal of Lightwave Technology, 2011Co-Authors: Scott Foster, Alexei Tikhomirov, John Van VelzenAbstract:The operating principle and theory of a fiber laser bender hydrophone is presented. We report experimental results for a micro-engineered silicon fiber laser hydrophone. The hydrophone has a flat pressure responsivity of 107 dB re Hz/Pa over a bandwidth exceeding 5 kHz, corresponding to ocean noise limited acoustic sensitivity. The first structural resonance of the hydrophone is 9 kHz in water and the acceleration rejection is in excess of 0 dB re ms-2/Pa up to 5 kHz.
R D Jenkins - One of the best experts on this subject based on the ideXlab platform.
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rheological properties of hydrophobically modified alkali soluble polymers effects of ethylene oxide chain length
Journal of Polymer Science Part B, 1998Co-Authors: K C Tam, R D Jenkins, M L Farmer, D R BassettAbstract:The rheological properties of hydrophobic alkali-soluble associative polymers (HASE) were studied using controlled rate (Mettler LS40) and controlled stress (TA CSL 500) rheometers. The effects of pH and polymer concentrations on the rheological properties of three HASE model polymer systems (i.e., HASE 5141, 5134, and 5142, with a degree of ethoxylation of 2.5, 10, and 40 mol, respectively) and a reference polymer without associative Hydrophobes (MAAEA) were examined. As the pH is increased by addition of ammonia to greater than 5–6, the carboxyl groups ionize to carboxylate ions and the polymers become water soluble. The HASE polymers thicken mainly by hydrophobic association. Viscosity can increase by two to three orders of magnitude as pH is raised to 9. The degree of ethoxylation in the macromonomer controls the nature of the hydrophobic association junctions by altering the flexibility and hydrophobicity of the macromonomer. Optimum thickening efficiency is observed in the system with approximately 10 mol of an ethylene–oxide spacer between the polymer backbone and the macromonomer. Viscoelastic study shows that the maximum thickening efficiency also corresponds to the dominant elastic property observed in the system with 10 mol of EO. All the model systems except the control system without Hydrophobe exhibit strain thickening of the viscous and elastic components. © 1998 John Wiley & Sons, Inc. J. Polym. Sci. B Polym. Phys. 36: 2275–2290, 1998
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rheological properties of model alkali soluble associative hase polymers effect of varying Hydrophobe chain length
Macromolecules, 1997Co-Authors: V Tirtaatmadja, K C Tam, R D JenkinsAbstract:The rheological properties of 1 wt % aqueous solutions (at pH between 8.7 and 9.5) of model associative (HASE) polymers are presented. These polymers are the polymerization product of methacrylic acid, ethyl acrylate, and macromonomers which contain Hydrophobes with the alkyl chain ranging in length from C12 to C20. At high pH, the polymers form a network of temporarily associating hydrophobic junctions, resulting in an enhancement of the shear viscosity which increases with the Hydrophobe chain length. Strain amplitude sweep results show that the strength of the hydrophobic association increases with the length of the Hydrophobe. This is also reflected in the increase in the ratio of the elastic to viscous components of the linear viscoelastic properties. When sheared beyond its equilibrium state, the associative polymers display a terminal (second-order) viscoelastic behavior at higher frequencies as the network is increasingly being disrupted by higher applied stresses. The general behavior of the poly...
Fang Li - One of the best experts on this subject based on the ideXlab platform.
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field test of an eight element fiber laser hydrophone array
OFS2012 22nd International Conference on Optical Fiber Sensors, 2012Co-Authors: Wentao Zhang, Fang LiAbstract:In this paper we repot the field test of an eight-element fiber laser hydrophone (FLH) array. The design of the fiber laser hydrophone, the schematic of the array, the WDM based interrogator system, and the field test results are given. The field test results show that the eight-element FLH array have equivalent performance as piezoelectric hydrophone array.
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an optimized design of a fiber optic hydrophone based on a flat diaphragm and multilayer fiber coils a theoretical approach
Measurement, 2009Co-Authors: Wentao Zhang, Fang LiAbstract:In this paper, we present a theoretical approach to optimize the design of a fiber optic hydrophone based on a flat diaphragm and multilayer fiber coils. In this theoretical analysis, both the radial and tangential strain induced fiber length changes are taken into account. The result shows that the position of the fiber coils and the number of the fiber layers have significant effects on the sensitivity, of the hydrophone. By optimizing these parameters, a higher sensitivity can be achieved. Sample hydrophones are fabricated and tested. The experimental result is in good agreement with the theoretical result, which shows this theoretical approach is effective in optimizing the design of the fiber optic hydrophone. (C) 2008 Elsevier Ltd. All rights reserved.
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fiber bragg grating hydrophone with high sensitivity
Chinese Optics Letters, 2008Co-Authors: Wentao Zhang, Fang LiAbstract:A fiber Bragg grating (FBG) hydrophone with high sensitivity was demonstrated. This hydrophone used a rubber diaphragm and a copper hard core as the sensing element. To compensate the hydrostatic pressure, a capillary tube was fixed at the end of the hydrophone. Theoretical analysis of the acoustic pressure sensitivity was given in this letter. Experiments were carried out to test the frequency response of the hydrophone. The result shows that when the Young's modulus of the diaphragm is higher, a flatter frequency response will be obtained.
