Symmetric Reflector Ultrasonic Transducers (SRUT) are a new type of ultrasonic transducer that take advantage of the ultrasonic wave emitted on the rear face of the active element. In this work, the electroacoustic modeling and characterization of such a structure is reported. Using the well-known KLM model, the electroacoustic response of a SRUT based on a piezoelectric ceramic with one matching layer

We present a case report that shows an abscopal effect in the context of a safety and efficacy clinical trial for histotripsy as ablation technique in liver tumors. The abscopal effect appears in the form of reduction of volume of non-treated tumor lesions in the same organ, as well as sustained reduction of tumor marker (CEA) that extends weeks away of the procedure. Histotripsy is a novel non-invasive

This work demonstrates that the combination of Multi-Line Transmission (MLT) and Short-Lag Spatial Coherence (SLSC) imaging improves the contrast of highly coherent structures within soft tissues, when compared to both traditional SLSC imaging and conventional Delay and Sum (DAS) beamforming. Experimental tests with small (i.e., 100 μm to 3 mm) targets embedded in homogeneous and heterogeneous backgrounds

X-ray induced acoustic computed tomography (XACT) provides X-ray absorption based contrast with acoustic detection. For its clinical translation, XACT imaging often has a limited field of view. This can result in image artifacts and overall loss of quantification accuracy. In this article, we aim to demonstrate model-based XACT image reconstruction to address these problems. An efficient matrix-free

Automated breast ultrasound image segmentation is essential in a Computer-Aided Diagnosis (CAD) system for breast tumors. In this paper, we present a Feature Pyramid Non-local Network (FPNN) with Transform Modal Ensemble Learning (TMEL) for accurate breast tumor segmentation in ultrasound images. Specifically, the FPNN fuses multi-level features under special consideration of long-range dependencies

The use of acoustic tweezers for precise manipulation of microparticles in the aqueous environment is essential and challenging for biomechanical applications in vivo. A 3D acoustic tweezer is developed in this study for three-dimensional manipulation by using a 2D phased array consisting of 256 elements operating at 1.04 MHz. The emission phases of each element are iteratively determined by a backpropagation

In this letter, for the first time, we investigate the role of Ferroelectric (FE) spacer in a Negative Capacitance (NC) FinFET. Using well-calibrated TCAD models, we found that instead of placing a Dielectric (DE) spacer, if we use a FE spacer, enhanced electric field due to FE polarization can be achieved thereby, producing a higher ON current. The fringing fields polarize the FE spacer and result

We report a method to locally assess the complex shear modulus of a viscoelastic medium. The proposed approach is based on the application of a magnetic force to a millimetre-sized steel sphere embedded in the medium and the subsequent monitoring of its dynamical response. A coil is used to create a magnetic field inducing the displacement of the sphere located inside a gelatin phantom. Then, a phased-array

This work aims to establish a theoretical framework for the modelling of bubble nucleation in histotripsy. A phenomenological version of the classical nucleation theory was parametrised with histotripsy experimental data, fitting a temperature-dependent activity factor that harmonises theoretical predictions and experimental data for bubble nucleation at both high and low temperatures. Simulations

Corrosion detection is a critical problem in many research areas. Guided wave tomography provides a powerful tool to estimate the remaining thickness of corroded structures. This paper introduces an ultrasonic quantitative tomography method called Fast Inversion Tomography (FIT) for corrosion mapping on plate-like structures. FIT consists of offline training and online inversion. The offline training

This paper proposes an innovative viscosity sensor based on the thickness-shear vibration of an SC-cut quartz resonator. The thickness-shear mode is firstly analyzed and further studied with fluid-structure interaction between the resonator and the viscous fluid loading. The characteristic equation is derived based on the 3D linear piezoelectric equations and solved for sensitivity analysis. Then laboratory

An algorithm for the fast computation of multi-static scattering patterns, produced by low-contrast inhomogeneous volumetric objects, which satisfy the Born approximation assumption, is presented. The algorithm relies on hierarchical interpolation and aggregation of optimally sampled phase-compensated partial contributions to the scattered field integral. The Born approximation enables the efficient

In the contemporary era of Internet-of-Things, there is an extensive search for competent devices which can operate at ultra-low voltage supply. Due to the restriction of power dissipation, a reduced sub-threshold swing based device appears to be the perfect solution for efficient computation. To counteract this issue, Negative Capacitance Fin field-effect transistors (NC-FinFETs) came up as the next

Acoustic radiation force impulse (ARFI) has been widely used in transient shear wave elasticity imaging (SWEI). For SWEI based on focused ARFI, the highest image quality exists inside the focal zone due to the limitation of depth of focus and diffraction. Consequently, the areas outside the focal zone and in the near field present poor image quality. To address the limitations of focused beam, we introduce

Deep learning is heavily being borrowed to solve problems in medical imaging applications and Siamese neural networks are the front-runners of motion tracking. In this paper, we propose to upgrade one such Siamese architecture-based neural network for robust and accurate landmark tracking in ultrasound images to improve the quality of image-guided radiation therapy. Although several researchers have

Increasing the local concentration of microbubbles (MBs) within the blood flow plays a crucial role in several medical applications, but there are few imaging modalities available for volumetric tracking of the aggregated MBs in real time. Here we describe a device integrating acoustic vortex tweezers (AVT) and ultrasound plane-wave imaging to achieve the goal of controlling the spatial distribution

Deep learning for ultrasound image formation is rapidly garnering research support and attention, quickly rising as the latest frontier in ultrasound image formation, with much promise to balance both image quality and display speed. Despite this promise, one challenge with identifying optimal solutions is the absence of unified evaluation methods and datasets that are not specific to a single research

The responsivity of an ultrasonic transducer is an important parameter in evaluating its effective frequency band, the electroacoustic conversion efficiency, and the measurement capability of the system. The determination of the responsivity of a traditional immersion or contact piezoelectric transducer has been well investigated. However, due to the high attenuation of waves propagating in air and

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Polyvinylidene fluoride (PVDF), a material with ferroelectric characteristics, is still extremely topical for the manufacturing of transducers, and different examples, some of which have been actively commercialized since the 1980s, are reported in the literature. In this work, we present a review focused on the PVDF technology for the manufacturing of in-air ultrasonic transducers, which found application

Pulse wave imaging (PWI) is an ultrasound imaging modality that estimates the wall stiffness of an imaged arterial segment by tracking the pulse wave propagation. The aim of the present study is to integrate PWI with vector flow imaging, enabling simultaneous and co-localized mapping of vessel wall mechanical properties and 2-D flow patterns. Two vector flow imaging techniques were implemented using

Presents the front cover for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

Presents the table of contents for this issue of the publication.

Polyvinylidene fluoride (PVDF), a material with ferroelectric characteristics, is still extremely topical for the manufacturing of transducers, and different examples, some of which have been actively commercialized since the 1980s, are reported in the literature. In this work, we present a review focused on the PVDF technology for the manufacturing of in-air ultrasonic transducers, which found application

Pulse wave imaging (PWI) is an ultrasound imaging modality that estimates the wall stiffness of an imaged arterial segment by tracking the pulse wave propagation. The aim of the present study is to integrate PWI with vector flow imaging, enabling simultaneous and co-localized mapping of vessel wall mechanical properties and 2-D flow patterns. Two vector flow imaging techniques were implemented using

Acoustic links for implantable medical devices (implants) have gained attention primarily because they provide a route to wireless deep-tissue systems. The miniaturization of the implants is a key research goal in these efforts, nominally because smaller implants result in less acute tissue damage. Implant size in most acoustic systems is limited by the piezoelectric bulk crystal used for power harvesting

Superheated perfluorocarbon nanodroplets are emerging ultrasound imaging contrast agents boasting biocompatible components, unique phase-change dynamics, and therapeutic loading capabilities. Upon exposure to a sufficiently high intensity pulse of acoustic energy, the nanodroplet's perfluorocarbon core undergoes a liquid-to-gas phase change and becomes an echogenic microbubble, providing ultrasound

The paper presents a study of special material properties of the single crystalline material Ca3TaGa3Si2O14 (CTGS=Catangasite). The comparatively highly ordered crystal structure and acceptable piezoelectric strength make it a candidate for microacoustic applications under extreme conditions. Obviously, low-loss dynamic behavior is typical for this crystal which consequently enables high temperature

The determination of complex elastic, piezoelectric, and dielectric coefficients of piezoelectric ceramics is important for precision engineering devices. Here, a novel method for determining the optimal material coefficients is presented. This method minimizes the average relative error in the values of conductance, susceptance, resistance, and reactance obtained from the one-dimensional model in

The use of super-resolution ultrasound (SR-US) imaging greatly improves visualization of microvascular structures, but clinical adoption is limited by long imaging times. This method depends on detecting and localizing isolated microbubbles (MBs), forcing the use of a dilute contrast agent concentration. Contrast-enhanced ultrasound (CEUS) image acquisition times as long as minutes arise as the localization

Accurate and fast velocity feedback signal is essential for the velocity control of ultrasonic motors (USMs). However, the low operating velocity of USMs results in a long velocity detection dead time (VDDT) of incremental encoders, which seriously restricts the dynamic control performance of USMs. Therefore, this paper presents a super-resolution velocity control (SRVC) scheme based on the velocity

A wedge transducer is developed using poly-phenylene-sulfide (PPS) as an exciter of high intensity surface acoustic wave (SAW) to remove droplets adhering to automobiles' front shield glass. Since the front shield glass has a glass/rubber/glass triple-layered configuration, SAW is needed to be employed to confine the vibration energy within the first glass layer and avoid the energy absorption in the

Cavitation is the fundamental physical mechanism of various focused ultrasound (FUS)-mediated therapies in the brain. Accurately knowing the 3D location of cavitation in real-time can improve the targeting accuracy and avoid off-target tissue damage. Existing techniques for 3D passive transcranial cavitation detection require the use of expensive and complicated hemispherical phased arrays with 128

We investigate a hybrid treatment-consists of an atmospheric pressure plasma pre-treatment, followed by an MHz surface acoustic waves treatment (SAW) with either DI water or plasma activated water (PAW)-on mung beans to accelerate the germination process, as mung bean sprout is one of the important food staples. For the early growth rate (after 320 mins), we observe that the hybrid treatment with PAW

This report presents the first demonstration of passive RF comb filters made using epitaxial GaN/NbN/SiC high overtone bulk acoustic resonators (epi-HBARs). The 2-port device is fabricated on electronic-grade GaN, electrically transduced, and acoustically coupled. The multi-mode epi-HBAR comb filter demonstrated here has 158 sharp filter passbands periodically distributed between 1 GHz - 4 GHz (L band

Accurate 3-D geometries of arteries and veins are important clinical data for diagnosis of arterial disease and intervention planning. Automatic segmentation of vessels in the transverse view suffers from the low lateral resolution and contrast. Convolutional neural networks are a promising tool for automatic segmentation of medical images, outperforming the traditional segmentation methods with high

Ultrasonic backscatter techniques may offer a useful approach for detecting changes in bone caused by osteoporosis. The goal of the present study was to investigate how bone mineral density (BMD) and the microstructure of human cancellous bone affect three ultrasonic backscatter parameters that have been identified as potentially useful for ultrasonic bone assessment purposes: apparent integrated backscatter

This paper presents a piezoelectric micromachined ultrasonic transducer (pMUT) modified with a piston diaphragm term as PD-pMUT (Piston Diaphragm pMUT). The transmission SPL and the frequency bandwidth of the modified transducer can be remarkably improved by adding a piston diaphragm on the central circular diaphragm. In this work, a lumped model, an acoustic resonance model, and an equivalent circuit

Coronary flow reserve (CFR), relating to the volumetric flow rate, is an effective functional parameter to assess the stenosis in left anterior descending (LAD) coronary artery. We have recently proposed to use high frame rate (HFR) contrast enhanced ultrasound (CEUS) to estimate the volumetric flow rate using ultrasound speckle decorrelation (SDC) without any assumptions about the velocity profile

LiNbO3 (LN) or LiTaO3 (LT) thin plates bonded to quartz are novel types of layered substrates for temperature-compensated surface acoustic wave (TCSAW) devices. In SAW resonators with Al electrodes arranged on LT/quartz and LN/quartz substrates, improved temperature behavior due to opposite signs of temperature coefficients of frequency (TCF) in quartz substrates and LT or LN plates can be combined

Synthetic Aperture (SA) beamforming is a principal technology of modern medical ultrasound imaging. In it the use of focused transmission provides superior signal-to-noise ratio and is promising for cardiovascular diagnosis at the maximum imaging depth about 160 mm. But there is a pitfall in increasing the frame rate to more than 80 frames per second (FPS) without image degradation by the haze artifact

The lack of time resolution restricts the quantitative detection of shallow subsurface defects with ultrasonic time-of-flight diffraction (TOFD) technique due to the superposition between lateral wave and diffracted waves from upper and lower tips. In this paper, frequency domain sparsity-decomposability inversion (FDSDI) method was proposed to enhance the time resolution in TOFD based on the sparsity

This paper investigates the dependence of transmitting sensitivity on the top electrode design of piezoelectric micromachined ultrasonic transducers (PMUTs). Two typical top electrodes, namely inner electrode (IE) and outer electrode (OE), are designed and fabricated. The measured transmitting velocities of the fabricated PMUTs at resonance under a drive voltage of 5 Vp-p (peak-to-peak) are 15.36 mm/s

Ultrasonic imaging is a common technique in Non-Destructive Evaluation, as it presents advantages such as low cost and safety of operation. In many industries, the interior inspection of objects with complex geometry has become a necessity. This kind of inspection requires the transducer to be coupled to the object with the use of some technique, such as immersing the object in water. When doing so

The conventional machine learning algorithm for analyzing ultrasonic signals to detect structural defects necessarily identifies and extracts either time or frequency domain features manually, which has problems in reliability and effectiveness. This work proposes a novel approach by combining convolution neural networks (CNN) and wavelet transform to analyze the laser generated ultrasonic signals

Three-dimensional (3D) freehand ultrasound (US) imaging has been applied to the investigation of spine deformity. However, it is a challenge for the current 3D imaging reconstruction algorithms to achieve a balance between image quality and computation time. The objectives of this paper are to implement a new fast reconstruction algorithm which can fulfill the request of immediate demonstration and

Lamb waves based structural health monitoring (SHM) has attracted extensive attention in recent years. This article aims to realize the functions of data communication, defect detection and energy transmission through piezoelectric transducers. In this work, the S0 mode at 500 kHz and A0 mode at 150 kHz are selected as the carrier waves and the optimized excitation frequencies are determined through

To solve the problem of resolution and contrast in plane wave imaging (PWI), coherent plane wave compounding (CPWC) was introduced, in which scanning was performed at different angles, which can achieve the desired image quality by combining the images obtained from PWI at different angles. However, the application of this idea reduces the frame rate in proportion to the number of plane waves (PW)

Super Resolution (SR) imaging has the potential of visualizing the micro-vasculature down to the 10 μm level, but motion induced by breathing, heartbeats, and muscle contractions are often significantly above this level. The paper therefore introduces a method for estimating tissue motion and compensating for this. The processing pipeline is described and validated using Field II simulations of an

Theoretical study of the effect of uniaxial pressure on the propagation characteristics of plate modes as Lamb and SH waves in a lithium niobate plate is carried out. A change in the effective crystalline symmetry, as well as the effective elastic constants under the pressure influence, has been derived. The controlling coefficients describing the pressure influence on the plate modes' phase velocities

Volumetric ultrasound imaging of blood flow with microbubbles enables more complete visualization of the microvasculature. Sparse arrays are ideal candidates to perform volumetric imaging at reduced manufacturing complexity and cable count. However, due to the small number of transducer elements, sparse arrays often come with high clutter levels, especially when wide beams are transmitted to increase

Although conventional Doppler ultrasound is widely used for quantifying blood flow, it is restricted by its low sensitivity to detect slow flow. The incorporation of ultrafast ultrasound and spatial-temporal clutter filters can not only extensively boost the Doppler sensitivity to low-velocity slow flow but also facilitate the development of advanced 3D Doppler techniques. In this work, we propose

Compared with Pb(Zr,Ti)O3 (PZT) ceramics, piezoelectric ceramic composites (PCCs), and piezoelectric polyvinylidene fluoride (PVDF) polymer, piezoelectric single crystal composites (PSCCs) are thought to be promising candidates for hydrophone applications because of their superior hydrostatic performance. However, due to the brittleness and small dimensions of single crystals, the preparation of large-area

We investigate the application of Ramsey spectroscopy for the development of a microcell atomic clock based on coherent population trapping (CPT). The dependence of the central Ramsey-CPT fringe properties on key experimental parameters is first studied for optimization of the clock short-term frequency stability. The sensitivity of the clock frequency to light-shift effects is then studied. In comparison

In many industrial sectors, Structural Health Monitoring (SHM) is considered as an addition to Non-Destructive Testing (NDT) that can reduce maintenance effort during lifetime of a technical facility, structural component or vehicle. A large number of SHM methods is based on ultrasonic waves, whose properties change depending on structural health. However, the wide application of SHM systems is limited

In ultrasound Nondestructive Testing (NDT), a widespread approach is to take synthetic aperture measurements from the surface of a specimen to detect and locate defects within it. Based on these measurements, imaging is usually performed using the Synthetic Aperture Focusing Technique (SAFT). However, SAFT is sub-optimal in terms of resolution and requires oversampling in time domain to obtain a fine

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