scholarly journals Experimental Characterization of A Piezoelectric Transducer Array Taking into Account Crosstalk Phenomenon

2020 ◽  
Vol 10 (1) ◽  
pp. 01-14
Author(s):  
Abdelmajid Bybi ◽  
Driss Khouili ◽  
Christian Granger ◽  
Mohammed Garoum ◽  
Ahmed Mzerd ◽  
...  
Keyword(s):  
Piezoelectric Transducer ◽  
Ultrasonic Transducer ◽  
Critical Role ◽  
Experimental Characterization ◽  
Transducer Array ◽  
The Third ◽  
Transducer Arrays ◽  
Piezoelectric Elements ◽  
Thickness Mode

Ultrasonic transducer arrays are generally composed of several piezoelectric elements arranged in 1D or 2D ways. Crosstalk is an undesirable phenomenon decreasing the performance of these devices. It generates parasitic displacements at the elements' radiating surfaces, which changes the directivity of the array. Furthermore, the transducer's displacement plays a critical role in terms of the focal area and transferred intensities. The objective of this paper is to characterize a piezoelectric array composed of seven-elements made of PZ 27 ceramic experimentally. It investigates the effects of the crosstalk phenomenon on the array's performance in particular. The results have shown that the array's elements vibrate mainly in thickness mode, but the displacement is not uniform along their length due to the contribution of a parasitic length mode. Moreover, the major parasitic displacements are obtained on the neighboring passive elements: about -7.3 dB, -11 dB, and -12 dB, on the first, the second, and the third elements, respectively.

scholarly journals Expression, Purification, and Characterization of (R)-Sulfolactate Dehydrogenase (ComC) from the Rumen MethanogenMethanobrevibacter milleraeSM9

Archaea ◽  
2017 ◽  
Vol 2017 ◽  
pp. 1-6
Author(s):  
Yanli Zhang ◽  
Linley R. Schofield ◽  
Carrie Sang ◽  
Debjit Dey ◽  
Ron S. Ronimus
Keyword(s):  
Biosynthetic Pathway ◽  
Critical Role ◽  
Reduction Reaction ◽  
Coenzyme M ◽  
Purification And Characterization ◽  
The Third ◽  
Optimal Activity ◽  
Methyl Coenzyme M Reductase

(R)-Sulfolactate dehydrogenase (EC 1.1.1.337), termed ComC, is a member of an NADH/NADPH-dependent oxidoreductase family of enzymes that catalyze the interconversion of 2-hydroxyacids into their corresponding 2-oxoacids. The ComC reaction is reversible and in the biosynthetic direction causes the conversion of (R)-sulfolactate to sulfopyruvate in the production of coenzyme M (2-mercaptoethanesulfonic acid). Coenzyme M is an essential cofactor required for the production of methane by the methyl-coenzyme M reductase complex. ComC catalyzes the third step in the first established biosynthetic pathway of coenzyme M and is also involved in methanopterin biosynthesis. In this study, ComC fromMethanobrevibacter milleraeSM9 was cloned and expressed inEscherichia coliand biochemically characterized. Sulfopyruvate was the preferred substrate using the reduction reaction, with 31% activity seen for oxaloacetate and 0.2% seen forα-ketoglutarate. Optimal activity was observed at pH 6.5. The apparentKMfor coenzyme (NADH) was 55.1 μM, and for sulfopyruvate, it was 196 μM (for sulfopyruvate theVmaxwas 93.9 μmol min−1 mg−1andkcatwas 62.8 s−1). The critical role of ComC in two separate cofactor pathways makes this enzyme a potential means of developing methanogen-specific inhibitors for controlling ruminant methane emissions which are increasingly being recognized as contributing to climate change.

scholarly journals Experimental Characterization of an Embossed Capacitive Micromachined Ultrasonic Transducer Cell

Micromachines ◽  
2020 ◽  
Vol 11 (2) ◽  
pp. 217
Author(s):  
Yuanyu Yu ◽  
Jiujiang Wang ◽  
Xin Liu ◽  
Sio Hang Pun ◽  
Shuang Zhang ◽  
...  
Keyword(s):  
Ultrasonic Transducer ◽  
Experimental Characterization ◽  
Release Process ◽  
Output Pressure ◽  
Collapse Mode ◽  
Acoustic Instruments ◽  
Capacitive Micromachined Ultrasonic Transducer ◽  
Collapse Region ◽  
High Output

Capacitive Micromachined Ultrasonic Transducer (CMUT) is a promising ultrasonic transducer in medical diagnosis and therapeutic applications that demand a high output pressure. The concept of a CMUT with an annular embossed pattern on a membrane working in collapse mode is proposed to further improve the output pressure. To evaluate the performance of an embossed CMUT cell, both the embossed and uniform membrane CMUT cells were fabricated in the same die with a customized six-mask sacrificial release process. An annular nickel pattern with the dimension of 3 μ m × 2 μ m (width × height) was formed on a full top electrode CMUT to realize an embossed CMUT cell. Experimental characterization was carried out with optical, electrical, and acoustic instruments on the embossed and uniform CMUT cells. The embossed CMUT cell achieved 27.1% improvement of output pressure in comparison to the uniform CMUT cell biased at 170 V voltage. The fractional bandwidths of the embossed and uniform CMUT cells were 52.5% and 41.8%, respectively. It substantiated that the embossed pattern should be placed at the vibrating center of the membrane for achieving a higher output pressure. The experimental characterization indicated that the embossed CMUT cell has better operational performance than the uniform CMUT cell in collapse region.

Design and Characterization of High-Density Ultrasonic Transducer Array

2018 ◽  
Vol 18 (6) ◽  
pp. 2285-2290 ◽  
Author(s):  
Jiang Ling ◽  
Yuan-Quan Chen ◽  
Yan Chen ◽  
Dan-Yang Wang ◽  
Yun-Fei Zhao ◽  
...  
Keyword(s):  
Ultrasonic Transducer ◽  
High Density ◽  
Transducer Array

scholarly journals Modeling and Experimental Characterization of Bonding Delaminations in Single-Element Ultrasonic Transducer

Materials ◽  
2021 ◽  
Vol 14 (9) ◽  
pp. 2269
Author(s):  
Wenxiang Ding ◽  
Maxime Bavencoffe ◽  
Marc Lethiecq
Keyword(s):  
Ultrasonic Transducer ◽  
Ultrasonic Transducers ◽  
Single Element ◽  
Experimental Characterization ◽  
The Finite Element Method ◽  
Matching Layer ◽  
Different Types ◽  
3D Printed ◽  
Piezoelectric Disk

Ultrasonic transducers performance can be seriously deteriorated by loss of adhesion between some constitutive elements such as the active element, the backing, or the matching layer. In the present work, the influence of bonding delaminations on the performance of a single-element ultrasonic transducer, which is composed of a piezoelectric disk, a backing, and a matching layer, is studied numerically and experimentally. Based on the positions between layers, two cases, i.e., delaminations between ceramic and backing or between ceramic and matching layer, are considered. Each case involves three different types of delaminations, which are marked as delamination type (DT)-I, II, and III. DT-I, a circular shape delamination, starts from the center and expands towards the peripheric zone; DT-II, an annular shape delamination, starts from the peripheric zone and expands towards the center; DT-III is a sector shape delamination with a given angle. The numerical simulations are performed by the finite element method and the influence of delaminations on the electromechanical admittance (EMA) of the transducer is investigated. 3D printed backings and matching layers are mounted on a PZT sample to assemble delaminated single-element transducers. An impedance analyzer is used for experimental measurements. Comparison between numerical and experimental results shows a reasonable agreement making changes in EMA an interesting indicator to inform about the occurrence and severity of delaminations in a single-element ultrasonic transducer.

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