CN115356402A - Integrated dual-frequency ultrasonic transducer, working method and application - Google Patents
Integrated dual-frequency ultrasonic transducer, working method and application Download PDFInfo
- Publication number
- CN115356402A CN115356402A CN202210817654.8A CN202210817654A CN115356402A CN 115356402 A CN115356402 A CN 115356402A CN 202210817654 A CN202210817654 A CN 202210817654A CN 115356402 A CN115356402 A CN 115356402A
- Authority
- CN
- China
- Prior art keywords
- frequency
- piezoelectric layer
- ultrasonic
- integrated dual
- low
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
Images
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N29/00—Investigating or analysing materials by the use of ultrasonic, sonic or infrasonic waves; Visualisation of the interior of objects by transmitting ultrasonic or sonic waves through the object
- G01N29/22—Details, e.g. general constructional or apparatus details
- G01N29/24—Probes
- G01N29/2437—Piezoelectric probes
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
- G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
- G01B17/02—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations for measuring thickness
Abstract
The invention discloses an integrated dual-frequency ultrasonic transducer, a working method and application, wherein in the integrated dual-frequency ultrasonic transducer, a high-frequency piezoelectric layer emits high-frequency ultrasonic waves and receives ultrasonic fundamental frequency components reflected by a sample to be tested, the ultrasonic fundamental frequency components are high-frequency ultrasonic signals with the same frequency as the high-frequency ultrasonic waves, an intermediate layer is laminated on the upper surface of the high-frequency piezoelectric layer, a low-frequency piezoelectric layer is laminated on the upper surface of the intermediate layer, the low-frequency piezoelectric layer receives ultrasonic static components reflected by the sample to be tested, and the ultrasonic static components are signals induced by the high-frequency ultrasonic waves and have carrier frequency of 0.
Description
Technical Field
The invention belongs to the technical field of ultrasonic nondestructive testing, and particularly relates to an integrated dual-frequency ultrasonic transducer, a working method and application.
Background
The ultrasonic static component is induced by nonlinear sources such as materials, microcracks and the like of ultrasonic waves in the sample propagation process, the carrier frequency of the ultrasonic static component is 0, and compared with the traditional fundamental frequency component and the high-order harmonic component, the ultrasonic static component has the characteristics of longer propagation distance and smaller sound attenuation.
In conventional non-destructive testing, the static component of the ultrasound is measured by a penetration method, which tends to make it difficult for the transmitting and receiving transducers to remain on the same axis, or the measurement results are susceptible to couplants, so that the measurement results may have large errors. For the existing integrated dual-frequency ultrasonic transducer, the low-frequency piezoelectric layer is used as a transmitting source, the high-frequency piezoelectric layer is used as a receiver and is used for harmonic imaging and the like, and the existing technology can not achieve self-transmitting and self-receiving measurement and has larger error.
The above information disclosed in this background section is only for enhancement of understanding of the background of the invention and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.
Disclosure of Invention
Aiming at the problems in the prior art, the invention provides an integrated dual-frequency ultrasonic transducer, a working method and application, which can realize the measurement of the spontaneous self-receiving ultrasonic fundamental frequency component and the static component and have high strategy precision.
The invention aims to realize the purpose by the following technical scheme, and the integrated dual-frequency ultrasonic transducer comprises:
the high-frequency piezoelectric layer transmits high-frequency ultrasonic waves and receives ultrasonic fundamental frequency components reflected back by a sample to be detected, and the ultrasonic fundamental frequency components are high-frequency ultrasonic wave signals with the same frequency as the high-frequency ultrasonic waves;
an intermediate layer laminated on an upper surface of the high-frequency piezoelectric layer;
the low-frequency piezoelectric layer is stacked on the upper surface of the middle layer and receives an ultrasonic static component reflected back by a sample to be detected, and the ultrasonic static component is a signal induced by the high-frequency ultrasonic waves and has a carrier frequency of 0.
In the integrated dual-frequency ultrasonic transducer, the high-frequency piezoelectric layer and the low-frequency piezoelectric layer are both thickness telescopic piezoelectric layers with electric fields parallel to the wave propagation direction.
In the integrated dual-frequency ultrasonic transducer, the length and the width of the high-frequency piezoelectric layer and the low-frequency piezoelectric layer are the same, and the thickness of the high-frequency piezoelectric layer and the low-frequency piezoelectric layer is half wavelength of the corresponding frequency.
In the integrated dual-frequency ultrasonic transducer, the length and the width of the high-frequency piezoelectric layer and the low-frequency piezoelectric layer are the same, and the length and the width are both more than 5 times larger than the thickness of the high-frequency piezoelectric layer.
In the integrated dual-frequency ultrasonic transducer, the materials of the high-frequency piezoelectric layer and the low-frequency piezoelectric layer comprise piezoelectric ceramics.
In the integrated dual-frequency ultrasonic transducer, the high-frequency piezoelectric layer is a high-frequency longitudinal wave piezoelectric wafer, and the low-frequency piezoelectric layer is a low-frequency longitudinal wave piezoelectric wafer.
In the integrated dual-frequency ultrasonic transducer, the upper surface of the low-frequency piezoelectric layer is laminated with a backing layer.
In the integrated dual-frequency ultrasonic transducer, the integrated dual-frequency ultrasonic transducer comprises a signal generator which sends a high-frequency emission signal to the high-frequency piezoelectric layer.
The working method of the integrated dual-frequency ultrasonic transducer comprises the following steps,
the signal generator generates a single high-frequency transmitting signal;
the transmitting signal excites the high-frequency piezoelectric layer to generate high-frequency ultrasonic waves;
the high-frequency ultrasonic wave generates static components when propagating in a sample, and after the high-frequency ultrasonic wave is reflected by the sample, the high-frequency piezoelectric layer receives ultrasonic fundamental frequency components through the duplexer, and the low-frequency piezoelectric layer receives the ultrasonic static components and converts the ultrasonic static components into electric signals.
The working method is applied, and self-retracting nonlinear ultrasonic detection and thickness measurement are realized by using the working method.
Compared with the prior art, the invention has the following advantages: the invention can realize the measurement of the self-receiving ultrasonic fundamental frequency component and the static component and can ensure smaller error.
Drawings
Various other advantages and benefits of the present invention will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The drawings are only for purposes of illustrating the preferred embodiments and are not to be construed as limiting the invention. It is obvious that the drawings described below are only some embodiments of the invention, and that for a person skilled in the art, other drawings can be derived from them without inventive effort. Also, like parts are designated by like reference numerals throughout the drawings.
In the drawings:
FIG. 1 is a schematic diagram of a dual frequency ultrasound transducer of the present invention;
description of the symbols: 1-high frequency piezoelectric layer, 2-middle layer, 3-low frequency piezoelectric layer, 4-back lining layer;
FIG. 2 is a schematic diagram of echo signals of fundamental frequency components and static components in a measured material (PPS is used in this embodiment, and the ultrasonic fundamental frequency component thereof is not completely attenuated) according to an embodiment of the present invention;
FIG. 3 is a schematic diagram showing echo signals of fundamental frequency components and static components in a measuring material (silicone rubber in this embodiment, whose ultrasonic fundamental frequency component has been completely attenuated) according to an embodiment of the present invention;
FIG. 4 is a time domain waveform of a transmit signal;
FIG. 5 is a frequency spectrum of a transmitted signal;
FIG. 6 is a received fundamental frequency component, stationary component time domain waveform (PPS thickness 50 mm);
FIG. 7 is a received fundamental frequency component, static component spectrum (PPS thickness 50 mm);
FIG. 8 is a time domain waveform of the received fundamental frequency component (silicone rubber thickness of 30.15 mm);
FIG. 9 is a received static component time domain waveform (silicone rubber thickness 30.15 mm);
fig. 10 is a spectrum of the static component received (silicone rubber thickness 30.15 mm).
The invention is further explained below with reference to the figures and examples.
Detailed Description
Specific embodiments of the present invention will be described in more detail below with reference to fig. 1 to 10. While specific embodiments of the invention are shown in the drawings, it should be understood that the invention may be embodied in various forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
It should be noted that certain terms are used throughout the description and claims to refer to particular components. As one skilled in the art will appreciate, various names may be used to refer to a component. This specification and claims do not intend to distinguish between components that differ in name but not function. In the following description and in the claims, the terms "include" and "comprise" are used in an open-ended fashion, and thus should be interpreted to mean "include, but not limited to. The description which follows is a preferred embodiment of the invention, but is made for the purpose of illustrating the general principles of the invention and not for the purpose of limiting the scope of the invention. The scope of the invention is to be determined by the claims appended hereto.
For the purpose of facilitating understanding of the embodiments of the present invention, the following description will be made by taking specific embodiments as examples with reference to the accompanying drawings, and the drawings are not to be construed as limiting the embodiments of the present invention.
For better understanding, as shown in fig. 1 to 10, in an integrated dual frequency ultrasonic transducer,
the high-frequency piezoelectric layer 1 transmits high-frequency ultrasonic waves and receives ultrasonic fundamental frequency components reflected back by a sample to be measured, the ultrasonic fundamental frequency components are high-frequency ultrasonic wave signals with the same frequency as the high-frequency ultrasonic waves,
an intermediate layer 2 laminated on an upper surface of the high-frequency piezoelectric layer 1,
and the low-frequency piezoelectric layer 3 is laminated on the upper surface of the intermediate layer 2, and the low-frequency piezoelectric layer 3 receives an ultrasonic static component reflected back by a sample to be detected, wherein the ultrasonic static component is a signal induced by the high-frequency ultrasonic waves and has a carrier frequency of 0.
In the preferred embodiment of the integrated dual-frequency ultrasonic transducer, the high-frequency piezoelectric layer 1 and the low-frequency piezoelectric layer 3 are both thickness-stretching piezoelectric layers with electric fields parallel to the wave propagation direction.
In the preferred embodiment of the integrated dual-frequency ultrasonic transducer, the lengths and widths of the high-frequency piezoelectric layer 1 and the low-frequency piezoelectric layer 3 are the same, and the thicknesses of the high-frequency piezoelectric layer 1 and the low-frequency piezoelectric layer 3 are half wavelengths of the respective corresponding frequencies.
In the preferred embodiment of the integrated dual-frequency ultrasonic transducer, the length and width of the high-frequency piezoelectric layer 1 and the low-frequency piezoelectric layer 3 are the same, and both the length and width are more than 5 times greater than the thickness of the high-frequency piezoelectric layer 1.
In the preferred embodiment of the integrated dual-frequency ultrasonic transducer, the materials of the high-frequency piezoelectric layer 1 and the low-frequency piezoelectric layer 3 comprise piezoelectric ceramics.
In the preferred embodiment of the integrated dual-frequency ultrasonic transducer, the high-frequency piezoelectric layer 1 is a high-frequency longitudinal wave piezoelectric wafer, and the low-frequency piezoelectric layer 3 is a low-frequency longitudinal wave piezoelectric wafer.
In the preferred embodiment of the integrated dual-frequency ultrasonic transducer, the backing layer 4 is laminated on the upper surface of the low-frequency piezoelectric layer 3.
In a preferred embodiment of the integrated dual frequency ultrasound transducer, the integrated dual frequency ultrasound transducer comprises a signal generator for sending a high frequency transmit signal towards the high frequency piezoelectric layer 1.
In one embodiment, an integrated dual frequency ultrasound transducer comprises: high frequency piezoelectric layer 1, intermediate layer 2, low frequency piezoelectric layer 3, backing layer 4. The lateral dimensions of the high frequency piezoelectric layer 1 and the low frequency piezoelectric layer 3 are kept uniform, with a thickness of half a wavelength of the respective corresponding frequency. The high-frequency piezoelectric layer 1 is contacted with a sample through a liquid couplant.
In one embodiment, the integrated dual-frequency ultrasonic transducer comprises a high-frequency piezoelectric layer 1, an intermediate layer 2, a low-frequency piezoelectric layer 3 and a backing layer 4 which are arranged from bottom to top in sequence, and the measurement of a self-contraction type ultrasonic fundamental frequency component and a static component is realized.
In one embodiment, the high-frequency piezoelectric layer 1 is used for transmitting high-frequency ultrasonic waves and receiving fundamental ultrasonic frequency components reflected back by a sample; the low frequency piezoelectric layer 3 is used to receive the static component of ultrasound induced by the non-linearity of the material, microcracks, etc. of the sample and reflected back.
In one embodiment, the high frequency piezoelectric layer 1 and the low frequency piezoelectric layer 3 are both thickness extensional piezoelectric layers with electric fields parallel to the wave propagation direction, the two piezoelectric layers operating at different center frequencies. The materials of the high frequency piezoelectric layer 1 and the low frequency piezoelectric layer 3 include, but are not limited to, piezoelectric ceramics, piezoelectric composites, and the like.
In one embodiment, the high frequency piezoelectric layer 1 is a high frequency longitudinal wave piezoelectric wafer and the low frequency piezoelectric layer 3 is a low frequency longitudinal wave piezoelectric wafer. The transverse dimensions of the high frequency piezoelectric layer 1 and the low frequency piezoelectric layer 3 are consistent in length and width and are more than 5 times of thickness, and the thickness is half wavelength of the corresponding frequency.
In one embodiment, the thickness of the intermediate layer 2 is equal to or less than a quarter wavelength of the corresponding high frequency ultrasound frequency, and the material is typically epoxy, AB glue or the like.
In one embodiment, the fundamental frequency component is a high-frequency ultrasonic signal having the same frequency as the excitation signal, and the static component is a signal induced by the excited high-frequency ultrasonic signal and having a carrier frequency of 0.
Referring to fig. 1, the integrated dual-frequency ultrasonic transducer comprises a high-frequency piezoelectric layer 1, an intermediate layer 2, a low-frequency piezoelectric layer 3 and a backing layer 4; the high-frequency piezoelectric layer 1 is a PZT piezoelectric ceramic rectangular sheet with the length of 26mm and the width of 20mm, the thickness of 0.4mm and the central frequency of 5MHz, the middle layer is an external clip type ultrasonic sensor coupling agent, the low-frequency piezoelectric layer 3 and the backing layer 4 are integrally formed by wide-band piezoelectric transducers with the size of 0.5 '× 1.0' and the central frequency of 0.5MHz, and in the measuring process, the high-frequency piezoelectric layer 1 is in contact with a sample through a liquid coupling agent.
Based on the integrated dual-frequency ultrasonic transducer of the above embodiment, as shown in fig. 2 and fig. 3, the computer controls the RAM-5000SNAP system to excite a hanning window modulated sinusoidal pulse signal with a center frequency of 5MHz and a frequency of 15, as shown in fig. 4, a spectrogram thereof is as shown in fig. 5, an excitation signal is loaded to the high-frequency piezoelectric wafer through the 2.25MHz high-pass filter to generate an ultrasonic longitudinal wave, the generation of an ultrasonic static component is induced due to material nonlinearity in the sample propagation process, after being reflected by the bottom surface, the high-frequency piezoelectric wafer is connected with the duplexer to receive a fundamental frequency echo signal, the low-frequency piezoelectric transducer receives a material whose fundamental frequency component echo signal of the static component echo signal is not completely attenuated, and the received static component echo signal needs to pass through the 1MHz low-pass filter; and the static component echo signal is received by the RAM-5000SNAP system and is displayed by the oscilloscope without being converted into an electric signal by a low-pass filter when the static component echo signal is received by the material with completely attenuated fundamental component echo signal.
Based on the above embodiment, PPS with a thickness of 50mm and silicone rubber with a thickness of 30.15mm are used for measurement, time domain and frequency spectrum of ultrasonic fundamental component and static component echo received signal of PPS with a thickness of 50mm are shown in fig. 6 and 7, and nonlinear ultrasonic detection and thickness measurement of self-receiving material can be realized by using ultrasonic static component echo signal and fundamental component echo signal; for the silicone rubber with the thickness of 30.15mm, the received ultrasonic fundamental frequency component echo time domain signal is shown in fig. 8, it can be seen that the ultrasonic fundamental frequency component is completely attenuated, the static component echo received time domain signal and the spectrogram are shown in fig. 9 and fig. 10, it can be seen that the static component is not completely attenuated, because the static component pulse carrier frequency is 0, the attenuation is reduced, the propagation distance is farther than the fundamental frequency component, and the thickness measurement of the self-receiving material can be realized by using the product of the flight time and the wave speed of two echoes of the ultrasonic static component.
Based on the integrated dual-frequency ultrasonic transducer, the invention also provides a self-transmitting and self-receiving type measuring method of the ultrasonic fundamental frequency component and the static component, which comprises the following steps:
the signal generator generates a single high-frequency transmitting signal;
the transmitting signal excites a high-frequency piezoelectric layer 1 of the dual-frequency ultrasonic transducer to generate a high-frequency ultrasonic signal;
when the high-frequency ultrasonic signal is transmitted in a sample, a static component generated by a nonlinear source such as a material, a microcrack and the like is reflected by the bottom surface, a high-frequency piezoelectric layer 1 of the dual-frequency ultrasonic transducer receives a fundamental frequency echo signal through a duplexer, a low-frequency piezoelectric layer 3 receives the static component echo signal, and the echo signal is converted into an electric signal.
In one embodiment, the working method of the integrated dual-frequency ultrasonic transducer comprises the following steps,
the signal generator generates a single high-frequency transmitting signal;
the transmitting signal excites the high-frequency piezoelectric layer 1 to generate high-frequency ultrasonic waves;
the high-frequency ultrasonic wave generates static components when propagating in a sample, the high-frequency piezoelectric layer 1 receives the ultrasonic fundamental frequency components through the duplexer after being reflected by the sample, and the low-frequency piezoelectric layer 3 receives the ultrasonic static components and converts the ultrasonic static components into electric signals.
According to the application of the working method, the working method is utilized to realize self-retracting nonlinear ultrasonic detection and thickness measurement.
Although the embodiments of the present invention have been described above with reference to the accompanying drawings, the present invention is not limited to the above-described embodiments and application fields, and the above-described embodiments are illustrative, instructive, and not restrictive. Those skilled in the art, having the benefit of this disclosure, may effect numerous modifications thereto without departing from the scope of the invention as defined by the appended claims.
Claims (10)
1. An integrated dual-frequency ultrasonic transducer is characterized by comprising,
the high-frequency piezoelectric layer transmits high-frequency ultrasonic waves and receives ultrasonic fundamental frequency components reflected back by a sample to be detected, and the ultrasonic fundamental frequency components are high-frequency ultrasonic wave signals with the same frequency as the high-frequency ultrasonic waves;
an intermediate layer laminated on an upper surface of the high-frequency piezoelectric layer;
the low-frequency piezoelectric layer is stacked on the upper surface of the middle layer and receives an ultrasonic static component reflected back by a sample to be detected, and the ultrasonic static component is a signal induced by the high-frequency ultrasonic waves and has a carrier frequency of 0.
2. The integrated dual frequency ultrasonic transducer of claim 1, wherein preferably both the high frequency piezoelectric layer and the low frequency piezoelectric layer are thickness extensional piezoelectric layers with electric fields parallel to the direction of wave propagation.
3. The integrated dual frequency ultrasonic transducer of claim 1, wherein the high frequency piezoelectric layer and the low frequency piezoelectric layer are the same in length and width, and the thickness of the high frequency piezoelectric layer and the low frequency piezoelectric layer is half wavelength of the respective corresponding frequencies.
4. The integrated dual frequency ultrasonic transducer of claim 3, wherein the high frequency piezoelectric layer and the low frequency piezoelectric layer have the same length and width, both of which are greater than 5 times the thickness of the high frequency piezoelectric layer.
5. The integrated dual frequency ultrasonic transducer of claim 1, wherein the material of the high frequency piezoelectric layer and the low frequency piezoelectric layer comprises a piezoelectric ceramic.
6. The integrated dual frequency ultrasound transducer of claim 1, wherein the high frequency piezoelectric layer is a high frequency longitudinal wave piezoelectric wafer and the low frequency piezoelectric layer is a low frequency longitudinal wave piezoelectric wafer.
7. The integrated dual frequency ultrasonic transducer of claim 1, wherein an upper surface of the low frequency piezoelectric layer is laminated to a backing layer.
8. The integrated dual frequency ultrasound transducer of claim 1, wherein the integrated dual frequency ultrasound transducer comprises a signal generator that sends a high frequency transmit signal towards the high frequency piezoelectric layer.
9. The method of operating an integrated dual frequency ultrasound transducer according to any of claims 1 to 8, comprising the steps of,
the signal generator generates a single high-frequency transmitting signal;
the transmitting signal excites the high-frequency piezoelectric layer to generate high-frequency ultrasonic waves;
the high-frequency ultrasonic wave generates static components when propagating in a sample, and after the high-frequency ultrasonic wave is reflected by the sample, the high-frequency piezoelectric layer receives ultrasonic fundamental frequency components through the duplexer, and the low-frequency piezoelectric layer receives the ultrasonic static components and converts the ultrasonic static components into electric signals.
10. Use of the working method according to claim 9 for self-retracting non-linear ultrasonic testing and thickness measurement.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210817654.8A CN115356402A (en) | 2022-07-12 | 2022-07-12 | Integrated dual-frequency ultrasonic transducer, working method and application |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210817654.8A CN115356402A (en) | 2022-07-12 | 2022-07-12 | Integrated dual-frequency ultrasonic transducer, working method and application |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN115356402A true CN115356402A (en) | 2022-11-18 |
Family
ID=84032615
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210817654.8A Pending CN115356402A (en) | 2022-07-12 | 2022-07-12 | Integrated dual-frequency ultrasonic transducer, working method and application |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN115356402A (en) |
-
2022
- 2022-07-12 CN CN202210817654.8A patent/CN115356402A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8176783B2 (en) | Non-contact fluid characterization in containers using ultrasonic waves | |
| Gan et al. | The use of broadband acoustic transducers and pulse-compression techniques for air-coupled ultrasonic imaging | |
| Monkhouse et al. | Flexible interdigital PVDF transducers for the generation of Lamb waves in structures | |
| CN109187754B (en) | Method for detecting pipeline microcrack by frequency-doubling modulation nonlinear ultrasonic guided wave time reversal | |
| Theobald et al. | Couplants and their influence on AE sensor sensitivity | |
| Goujon et al. | Behaviour of acoustic emission sensors using broadband calibration techniques | |
| Wright et al. | Air-coupled ultrasonic testing of metals using broadband pulses in through-transmission | |
| JP4795925B2 (en) | Ultrasonic thickness measurement method and apparatus | |
| CN110824017B (en) | Soft material acoustic parameter measuring method | |
| CN115356402A (en) | Integrated dual-frequency ultrasonic transducer, working method and application | |
| Gan et al. | A swept frequency multiplication technique for air-coupled ultrasonic NDE | |
| Duncan | Real-time analysis signal processor for ultrasonic nondestructive testing | |
| Simonetti et al. | Ultrasonic interferometry for the measurement of shear velocity and attenuation in viscoelastic solids | |
| CN112285202A (en) | Variable-curvature PBX surface crack oriented nondestructive testing method and sensor | |
| Berndt et al. | Feasibility study of a nonlinear ultrasonic technique to evaluate adhesive bonds | |
| Lai et al. | Ultrasonic resonance spectroscopic analysis of microliters of liquids | |
| Battaglini et al. | The use of pulse compression and frequency modulated continuous wave to improve ultrasonic non destructive evaluation of highly-scattering materials | |
| Lee et al. | A double-layered line-focusing PVDF transducer and V (z) measurement of surface acoustic wave | |
| Smith et al. | Factors in the design of ultrasonic probes | |
| RU2814451C1 (en) | Dual-mode electroacoustic transducer | |
| 张浩 et al. | Development of air-coupled ultrasonic transducer for material surface defect detection | |
| Renken et al. | Accuracy of resonant ultrasound spectroscopy: An experimental study | |
| Leo-Shin et al. | Nondestructive determination of elastic constants of thin plates based on PVDF focusing ultrasound transducers and Lamb wave measurements | |
| RU2005126996A (en) | METHOD FOR DETERMINING THE ATTENUATION FACTOR OF THE ULTRASONIC OSCILLATIONS IN THE MATERIAL | |
| Kim et al. | Measurements of the longitudinal wave speed in thin materials using a wideband PVDF transducer |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |