Influences of length and position of drive-stacks on the transmitting-voltage-response of the broadband Tonpilz transducer

2021 ◽  
Vol 150 (6) ◽  
pp. 4140-4150
Author(s):  
Bocheng Ji ◽  
Lianjin Hong ◽  
Yu Lan
Keyword(s):  
Voltage Response

scholarly journals Research and Fabrication of Broadband Ring Flextensional Underwater Transducer

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1548
Author(s):  
Jiuling Hu ◽  
Lianjin Hong ◽  
Lili Yin ◽  
Yu Lan ◽  
Hao Sun ◽  
...  
Keyword(s):  
High Speed ◽  
Structural Parameters ◽  
Low Frequency ◽  
Flexural Vibration ◽  
Underwater Acoustic Communication ◽  
Voltage Response ◽  
Water Tank ◽  
Spherical Cap ◽  
Finite Element Software ◽  
Underwater Transducer

At present, high-speed underwater acoustic communication requires underwater transducers with the characteristics of low frequency and broadband. The low-frequency transducers also are expected to be low-frequency directional for realization of point-to-point communication. In order to achieve the above targets, this paper proposes a new type of flextensional transducer which is constructed of double mosaic piezoelectric ceramic rings and spherical cap metal shells. The transducer realizes broadband transmission by means of the coupling between radial vibration of the piezoelectric rings and high-order flexural vibration of the spherical cap metal shells. The low-frequency directional transmission of the transducer is realized by using excitation signals with different amplitude and phase on two mosaic piezoelectric rings. The relationship between transmitting voltage response (TVR), resonance frequency and structural parameters of the transducer is analyzed by finite element software COMSOL. The broadband performance of the transducer is also optimized. On this basis, the low-frequency directivity of the transducer is further analyzed and the ratio of the excitation signals of the two piezoelectric rings is obtained. Finally, a prototype of the broadband ring flextensional underwater transducer is fabricated according to the results of simulation. The electroacoustic performance of the transducer is tested in an anechoic water tank. Experimental results show that the maximum TVR of the transducer is 147.2 dB and the operation bandwidth is 1.5–4 kHz, which means that the transducer has good low-frequency, broadband transmission capability. Meanwhile, cardioid directivity is obtained at 1.4 kHz and low-frequency directivity is realized.

Subthreshold frequency selectivity in avian auditory thalamus

1994 ◽  
Vol 71 (4) ◽  
pp. 1361-1372 ◽  
Author(s):  
B. Strohmann ◽  
D. W. Schwarz ◽  
E. Puil
Keyword(s):  
Frequency Selectivity ◽  
Membrane Properties ◽  
Resting Potential ◽  
Resonant Peak ◽  
Auditory Signal ◽  
Voltage Response ◽  
Potential Range ◽  
Na Current ◽  
Frequency Responses ◽  
Low Threshold

1. We studied the frequency responses of neurons in the nucleus ovoidalis (OV), the principal thalamic auditory relay nucleus of the chicken, in the subthreshold range of membrane potentials. The frequency response is the impedance amplitude profile evident in the voltage response to a broadband stimulus. The stimulus was a deterministic periodic current input of small amplitude, sweeping through a specified frequency range. We used whole-cell, tight-seal recording techniques in slices to study the voltage responses and membrane properties in current and voltage clamp. 2. Generally, low-frequency resonant humps with peak impedances of approximately 6 Hz characterized the frequency responses of OV neurons. This resonance was the principal determinant for frequency selectivity in the majority of OV neurons expressing only a tonic mode of firing. 3. The 6-Hz resonance was voltage dependent and most distinct where the activation ranges of a hyperpolarization activated inward current (IH) and a persistent Na+ current tend to overlap. The potential range for optimal resonance often included the resting potential. 4. Application of the Na+ current antagonist, tetrodotoxin, blocked the persistent Na+ current and most of the resonant hump at depolarized levels but did not affect the resonant peak along the frequency axis. Thus the persistent Na+ current may serve to amplify the resonance. 5. Extracellular application of Cs+, but not Ba2+, blocked a voltage sag during pulsed hyperpolarization as well as the IH current. Application of Cs+ also eliminated the 6-Hz resonance. An IH seems, therefore, instrumental for the resonance. 6. A minority of neurons that expressed low-threshold Ca2+ spikes and burst firing at hyperpolarized states displayed voltage oscillations at 2-4 Hz, spontaneously or in response to pulsatile stimuli. Application of Ni2+ blocked the oscillations and the low-threshold spikes, presumably produced by a T-type Ca2+ current. The resonance at 6 Hz, however, was only slightly affected by Ni2+. A T-type current, therefore, is critical for the 2- to 4-Hz oscillations. 7. Membrane resonance may dominate the power spectrum of subthreshold potential fluctuations. The resonance demonstrated in vitro may be stabilized by experimental procedures; its frequency may be different and more variable in vivo. Resonances in thalamic neurons may play a role in auditory signal processing in birds.

A Flextensional Transducer Prototype with PVDF Piezoelectric Film

2014 ◽  
Vol 670-671 ◽  
pp. 1153-1158
Author(s):  
Jing Jing Liu ◽  
Lei Qin ◽  
Li Kun Wang ◽  
Chao Zhong ◽  
Bin Zhang ◽  
...  
Keyword(s):  
Polyvinylidene Fluoride ◽  
Laser Scanning ◽  
Longitudinal Vibration ◽  
Voltage Response ◽  
Acoustic Measurement ◽  
Piezoelectric Film ◽  
Radial Vibration ◽  
Frequency Bandwidth ◽  
Metallic Shell ◽  
Flextensional Transducer

This paper presents a prototype of a new flextensional transducer with PVDF (Polyvinylidene Fluoride) piezoelectric film instead of metallic shell. Resonance frequency, bandwidth, transmitting voltage response, and horizontal directivity of the flextensional transducer with PVDF piezoelectric film were respectively measured by using laser-scanning vibrometer, and underwater acoustic measurement system. Experimental results showed that the new transducer features effectively conversion from longitudinal vibration of piezoelectric stack into radial vibration of PVDF piezoelectric film.

scholarly journals A Review: Carbon Nanotube-Based Piezoresistive Strain Sensors

2012 ◽  
Vol 2012 ◽  
pp. 1-15 ◽  
Author(s):  
Waris Obitayo ◽  
Tao Liu
Keyword(s):  
Carbon Nanotubes ◽  
Carbon Nanotube ◽  
Composite Films ◽  
Strain Sensors ◽  
Voltage Response ◽  
Strain Sensing ◽  
Multiwalled Carbon ◽  
Sensing Applications ◽  
Mechanical Deformations ◽  
Electrical Resistivities

The use of carbon nanotubes for piezoresistive strain sensors has acquired significant attention due to its unique electromechanical properties. In this comprehensive review paper, we discussed some important aspects of carbon nanotubes for strain sensing at both the nanoscale and macroscale. Carbon nanotubes undergo changes in their band structures when subjected to mechanical deformations. This phenomenon makes them applicable for strain sensing applications. This paper signifies the type of carbon nanotubes best suitable for piezoresistive strain sensors. The electrical resistivities of carbon nanotube thin film increase linearly with strain, making it an ideal material for a piezoresistive strain sensor. Carbon nanotube composite films, which are usually fabricated by mixing small amounts of single-walled or multiwalled carbon nanotubes with selected polymers, have shown promising characteristics of piezoresistive strain sensors. Studies also show that carbon nanotubes display a stable and predictable voltage response as a function of temperature.

ZINC OXIDE NANOPARTICLES FOR ULTRAVIOLET PHOTODETECTION

2011 ◽  
Vol 20 (01) ◽  
pp. 183-194 ◽  
Author(s):  
SHAYLA SAWYER ◽  
LIQIAO QIN ◽  
CHRISTOPHER SHING
Keyword(s):  
Zinc Oxide ◽  
Gallium Nitride ◽  
Zno Nanoparticles ◽  
Green Emission ◽  
Synthesis Process ◽  
Voltage Response ◽  
Zno Nanoparticle ◽  
Linear Current ◽  
Current Voltage ◽  
Lift Off

Zinc Oxide ( ZnO ) nanoparticles were created by a top-down wet-chemistry synthesis process ( ZnO - A ) and then coated with polyvinyl-alcohol (PVA) ( ZnO - U ). In ZnO - U , strong UV emission was apparent while the parasitic green emission, which normally appears in ZnO suspensions, was suppressed. A standard lift-off process via e-beam lithography was used to fabricate a detector by evaporating Aluminum ( Al ) as ohmic electrodes on the ZnO nanoparticle film. Photoconductivity experiments showed that linear current-voltage response were achieved and the ZnO - U nanoparticles based detector had a ratio of UV photo-generated current more than 5 times better than that of the ZnO - A based detector. In addition, non-linear current-voltage responses were observed when interdigitated finger Gold ( Au ) contacts were deposited on ZnO - U . The UV generated current to dark current ratios were between 4 and 7 orders of magnitude, showing better performance than the photodetector with Al contacts. ZnO - U were also deposited on Gallium Nitride ( GaN ) and Aluminum Gallium Nitride ( AlGaN ) substrates to create spectrally selective photodetectors. The responsivity of detector based on AlGaN is twice that of commercial UV enhanced Silicon photodiodes. These results confirmed that ZnO nanoparticles coating with PVA is a good material for small-signal, visible blind, and wavelength selective UV detection.

The use and misuse of apparent resistivity in electromagnetic methods

Geophysics ◽  
1986 ◽  
Vol 51 (7) ◽  
pp. 1462-1471 ◽  
Author(s):  
Brian R. Spies ◽  
Dwight E. Eggers
Keyword(s):  
Apparent Resistivity ◽  
Early Time ◽  
Asymptotic Formulas ◽  
Voltage Response ◽  
Late Time ◽  
Induced Voltage ◽  
Resistivity Curve ◽  
Transient Electromagnetic ◽  
Electromagnetic Methods ◽  
Tem Method

Problems and misunderstandings arise with the concept of apparent resistivity when the analogy between an apparent resistivity computed from geophysical observations and the true resistivity structure of the subsurface is drawn too tightly. Several definitions of apparent resistivity are available for use in electromagnetic methods; however, those most commonly used do not always exhibit the best behavior. Many of the features of the apparent resistivity curve which have been interpreted as physically significant with one definition disappear when alternative definitions are used. It is misleading to compare the detection or resolution capabilities of different field systems or configurations solely on the basis of the apparent resistivity curve. For the in‐loop transient electromagnetic (TEM) method, apparent resistivity computed from the magnetic field response displays much better behavior than that computed from the induced voltage response. A comparison of “exact” and “asymptotic” formulas for the TEM method reveals that automated schemes for distinguishing early‐time and late‐time branches are at best tenuous, and those schemes are doomed to failure for a certain class of resistivity structures (e.g., the loop size is large compared to the layer thickness). For the magnetotelluric (MT) method, apparent resistivity curves defined from the real part of the impedance exhibit much better behavior than curves based on the conventional definition that uses the magnitude of the impedance. Results of using this new definition have characteristics similar to apparent resistivity obtained from time‐domain processing.

Power system inertia estimation: Utilization of frequency and voltage response after a disturbance

2018 ◽  
Vol 161 ◽  
pp. 52-60 ◽  
Author(s):  
Dimitrios Zografos ◽  
Mehrdad Ghandhari ◽  
Robert Eriksson
Keyword(s):  
Power System ◽  
Voltage Response ◽  
System Inertia

scholarly journals Bifurcation, chaotic and hysteresis phenomena of broadband tristable energy harvesters

2018 ◽  
Vol 241 ◽  
pp. 01025
Author(s):  
Shengxi Zhou ◽  
Junyi Cao ◽  
Grzegorz Litak
Keyword(s):  
Multiple Solutions ◽  
Nonlinear Effects ◽  
Basins Of Attraction ◽  
Voltage Response ◽  
Mechanical Resonator ◽  
Potential Wells ◽  
Energy Harvesters ◽  
Characteristic Features ◽  
Bifurcation Chaotic ◽  
Hysteresis Phenomena

We analyze energy harvesting using a mechanical resonator with three potential wells. Nonlinear effects are leading to frequency broadband voltage response via bifurcations, multiple solutions and dynamical hysteresis. We show the characteristic features of the obtained solutions. In particular, basins of attraction of solutions are discussed.

Sign in / Sign up

Export Citation Format

Share Document