Acoustic Field Research Articles

Use of Resonant Acoustic Fields as Atmospheric-Pressure Ion Gates.

Ion optics are crucial for spectrometric methods such as mass spectrometry (MS) and ion mobility spectrometry (IMS). Among the wide selection of ion optics, temporal ion gates are of particular importance for time-of-flight MS (TOF-MS) and drift-tube IMS. Commonly implemented as electrostatic ion gates, these optics offer a rapid, efficient means to block ion beams and form discrete ion packets for subsequent analysis. Unfortunately, these devices rely on pulsed high voltage sources and are not fully transparent, even in their open state, which can lead to ion losses and contamination. Here, a novel atmospheric-pressure ion gate based on a resonant acoustic field structure is described. This effect was accomplished through the formation of a resonant, standing acoustic wave of alternating nodes and antinodes. Alignment of an atmospheric-pressure gaseous ion beam with an antinode, i.e. a region of transient pressure, of the acoustic structure acted as a gate and blocked ions from impinging on ion-selective detectors, such as a mass spectrometer and a Faraday plate. The velocity of the ion stream and acoustic power were found to be critical parameters for gating efficiency. In the presence of an acoustic field (i.e., a closed gate), ion signals decreased by as much as 99.8% with a response time faster than the readout of the ion-measurement devices used here (ca. 75 ms). This work demonstrates the basis for a low-cost, acoustic ion gate, which is optically transparent and easily constructed with low-power, off-the-shelf components, that could potentially be used with MS and IMS instrumentation.

Research on attenuation rate correlation calibration method based on acoustic variable density logging

In order to solve the problem of logging calibration without a free pipe in the process of acoustic variable density logging and the subjective problem of the free pipe calibration method, this paper studies an attenuation rate calibration method based on acoustic variable density logging. Using the developed acoustic wave probe response relationship device and the acoustic wave probe calibration device, the response consistency of the receiving probe of the acoustic wave instrument and the frequency of the transmitting probe can be calibrated in the laboratory, and the response consistency and frequency calibration coefficient can be obtained. Through this coefficient, the acoustic wave attenuation rate can be derived. After converting the acoustic wave attenuation rate into a relative sound amplitude, the scale coefficients of the well can be obtained. The relative acoustic amplitude of each measuring point in the well can be obtained by using the scale coefficient to evaluate the cementing quality. The acoustic variable density field test of 18 wells in the oilfield shows that the relative acoustic amplitude calculation results obtained by the attenuation rate correlation calibration method are basically consistent with the theoretical values, and the maximum deviation is 6.9%. The deviation is caused by the presence of ahead fluid in the outer annulus of the casing, the presence of trace bubbles in the casing, and the incomplete centering of the instrument. Compared with the traditional free pipe calibration method, the attenuation rate correlation calibration method innovatively replaces the free pipe calibration in the well with the indoor calibration of the acoustic instrument and solves the problem of acoustic variable density calibration when there is no free pipe in cementing quality logging. This method has better accuracy and a greater application range, which lays a foundation for the quantitative interpretation of acoustic variable density.

Driving Rotational Circulation in a Microfluidic Chamber Using Dual Focused Surface-Acoustic-Wave Beams

In this paper, enhanced rotational circulation in a circular microfluidic chamber driven by dual focused surface-acoustic-wave (SAW) beams is presented. To characterize the resonant frequency and focusing effect, we simulate the focused SAW field excited by an arc-shaped interdigital transducer patterned on a 128°Y-cut lithium-niobate (LiNbO3) substrate using a finite element method. A full three-dimensional perturbation model of the combined system of the microfluidic chamber and the SAW device is conducted to obtain the acoustic pressure and acoustic streaming fields, which show rotational acoustic pressure and encircling streaming resulted in the chamber. Accordingly, the SAW acoustofluidic system is realized using microfabrication techniques and applied to perform acoustophoresis experiments on submicron particles suspending in the microfluidic chamber. The result verifies the rotational circulation motion of the streaming flow, which is attributed to enhanced angular momentum flux injection and Eckart streaming effect through the dual focused SAW beams. Our results should be of importance in driving particle circulation and enhancing mass transfer in chamber embedded microfluidic channels, which may have promising applications in accelerating bioparticle or cell reactions and fusion, enhancing biochemical and electrochemical sensing, and efficient microfluidic mixing.

Numerical Simulation Analysis of Laser Ultrasonic Detection of Defects in Silicon Carbide

Silicon carbide (SiC) is widely used in power electronic devices and other fields, the defects of which can significantly impact its performance in device fabrication. Laser ultrasonic non-destructive testing (NDT) as a novel and effective approach can detect these defects in real time. This study introduces a numerical model for the SiC NDT that elucidates the dynamic interactions between laser-induced ultrasonic waves and surface defects, and internal defects in SiC, respectively. Results show NDT is an effective way to locate the SiC defect and the ultrasonic waves’ vibration amplitude of detection points at defect edges increases by at least 16% compared to adjacent points, with a maximum of 43%. A comparative assessment between surface and internal defect vibration responses for acoustic is also made. For internal defects, the oscillation time of the acoustic wave at the detection point on the surface away from the edge of the defect at the excitation point exceeds that of surface defects by 100 ns, and the amplitude near the excitation point is more pronounced, reaching 1.44 nm, which is 4.2 times that of corresponding surface defects. Additionally, a linear relationship is observed between the arrival time of transmitted Rayleigh Waves (RSR) and internal defect length, with a correlation coefficient of 0.9878. Similarly, a linear relationship is established between the amplitude of reflected Rayleigh Waves (rR) and defect width, with a correlation coefficient of 0.9976, providing an effective way to quantify the inner defect. Furthermore, transient temperature profiles at distinct positions and transient acoustic fields and the relationship of acoustic vibration amplitude increasing with laser spot size under a fixed laser power density are also analyzed. This model provides a theoretical foundation for laser ultrasonic NDT setup and choice of micro-vibration detection device.

Precision of the acoustic control of single-photon scattering with semiconductor quantum dots

Acoustic modulation of quantum dots (QDs) allows one to control the scattering of photons. Here we theoretically characterize the degree of this acoustic control in the frequency domain. We formulate the theory of low-intensity resonance fluorescence (RF) in the presence of white noise and show that a high level of control is achievable with a two-tone acoustic field for appropriate settings of modulation amplitudes as long as the noise-induced phase diffusion coefficient remains one order of magnitude smaller than the acoustic frequency. In addition, using a quantitative model of optical signal collection, we determine that the acoustic phase must be stable over 104 to 105 acoustic periods for efficient control.

Post-immersive Listening: Perspectives on the Mediation of Sonic Environments

Unplanned meetings can stem from complex movements across geographies, with serendipity playing a key role. Media artist Budhaditya Chattopadhyay unexpectedly meets researcher Budhaditya Chattopadhyay at a café in Budapest. This is their eighth meeting, following previous encounters in Copenhagen (2017), Den Haag (2021c), Kolkata (2021b), Berlin (2022a), Beirut (2022b), Basel (2023), and Rampurhat (2024). Each interaction has fostered a reflexive exchange of ideas, merging their artistic and theoretical perspectives on sound, listening, migratory experiences, and decolonial activism. Despite the differing lenses they bring, their conversations generate new insights. In the bustling café, surrounded by disengaged students emblematic of the isolation in European universities, the two engage in thoughtful discussions on acoustic ecologies, sonic environments, field recording, and audiovisual media. Their dialogue embodies a spirit of camaraderie, underscoring the value of interdisciplinary exchanges in nurturing knowledge and understanding across artistic and scholarly domains.

Numerical Simulation and Comprehensive Analysis of Double-Layer Elastic Acoustic Materials as Proppants for Sonic Logging

This study presents a comprehensive numerical and theoretical investigation into the acoustic scattering properties of double-layer elastic spheres, designed as functional particles for enhancing sonic logging accuracy in reservoir exploration. By analyzing the normalized maximum scattering sound field under various external conditions, the research identifies critical parameters influencing acoustic scattering performance, including incident wave frequency, outer particle radius, and the elastic modulus of the outer material. The results demonstrate that the normalized maximum scattering field for a single-layer elastic sphere is approximately 2.0, while the introduction of a double-layer configuration increases this value to around 2.5, representing a 25% improvement in scattering performance. This enhancement underscores the effectiveness of the double-layer structure in optimizing scattering characteristics, particularly under challenging operational conditions. These findings provide a robust theoretical framework for the design and application of intelligent acoustic materials, enabling precise acoustic field control and improved logging accuracy in complex reservoir environments. This work advances the interdisciplinary understanding of acoustics and materials science, offering innovative insights into the development of next-generation sonic logging technologies for demanding exploration scenarios.

Issues in the Design and Validation of Coupled Reverberation Roomsfor Testing Acoustic Insulation of Building Partitions

The paper presents the characteristics of the sound field in two pairs of coupled reverberation rooms, designed in accordance with International Organization for Standardization [ISO] (2021c). The analyses are based on the results of the following studies. Firstly, the acoustic airborne sound insulation of selected test samples was measured in the reverberation rooms without using any sound diffusing nor sound absorbing elements. In the second step, the tests were repeated successively with an increasing number of diffusers installed in the rooms. The last stage of the research involved measurements with additional absorbers mounted in the rooms. The results show that although the geometry and construction of the reverberation rooms are in line with the standard guidelines, in most situations it was necessary to use diffusing and absorbing elements to improve the acoustic field in the rooms. Such elements, however, are very undesirable as they significantly limit the usable space of the rooms, making it more difficult to assemble samples and distribute sources and measurement points in the measurement space. Later in the article, the authors prove that even using typically available design tools, i.e., 1st and 2nd Bonello criterions, numerical simulations with the image-source method and the finite element method, or more advanced research methods, such as measurements using scaled samples, it seems impossible to prevent at the design stage the future necessity of using additional diffusing and absorbing elements in the reverberation rooms. Only via verification by measurements performed in the completed rooms provides the assessment if such additional elements are required.

Imaging transverse modes in a gigahertz surface-acoustic-wave cavity

Full characterization of surface-acoustic-wave (SAW) devices requires imaging the spatial distribution of the acoustic field, which is not possible with standard all-electrical measurements where an interdigital transducer is used as a detector. Here we present a fiber-based scanning Michelson interferometer employing a strongly focused laser beam as a probe. Combined with a heterodyne circuit, this setup enables frequency- and spatially resolved measurements of the amplitude and phase of the SAW out-of-plane displacement. We demonstrate this by investigating a 1-GHz SAW cavity, revealing the presence of frequency-overlapping transverse modes, which are not resolved with an all-electrical measurement. The frequency overlap of these transverse modes leads to mode superpositions, which we analyze by quadrature decomposition of the complex acoustic field. Published by the American Physical Society 2025

A comparative study of experimental and simulated ultrasound beam propagation through cranial bones

Objective.Transcranial ultrasound is used in a variety of treatments, including neuromodulation, opening the blood-brain barrier, and high intensity focused ultrasound therapies. To ensure safety and efficacy of these treatments, numerical simulations of the ultrasound field within the brain are used for treatment planning and evaluation. This study investigates the accuracy of numerical modelling of the propagation of focused ultrasound through cranial bones.Approach.Holograms of acoustic fields after propagation through four human skull specimens were measured for frequencies ranging from 270 kHz to 1 MHz, using both quasi-continuous and pulsed modes. The open-source k-Wave toolbox was employed for simulations, using an equivalent-source hologram and a uniform bowl source with parameters that best matched the measured free-field pressure distribution.Main results.The average absolute error in k-Wave simulations with sound speed and density derived from CT scans compared to measurements was 15% for the spatial-peak acoustic pressure amplitude, 2.7 mm for the position of the focus, and 35% for the focal volume. Optimised uniform bowl sources achieved calculation accuracy comparable to that of the hologram sources.Significance.This method is demonstrated as a suitable tool for prediction of focal position, size and overall distribution of transcranial ultrasound fields. The accuracy of the shape and position of the focal region demonstrate the suitability of the sound speed and density mapping used here. However, large errors in pressure amplitude and transmission loss in some individual cases show that alternative methods for mapping individual skull attenuation are needed and the possibility of considerable errors in pressure amplitude should be taken into account when planning focused ultrasound studies or interventions in the human brain, and appropriate safety margins should be used.

Radial self-accelerating acoustic beam for three-dimensional helical motion of microparticles

Abstract Radially self-accelerating acoustic beams (RSABs) with rotating field distributions enable three-dimensional manipulation of particles. Nevertheless, the generation of desired RSABs is always a challenge. In this study, we derive a general form for the RSABs with a rotating acoustic field. We investigate the correlation between acoustic intensity and phase distribution of the RSAB in-depth via theoretical calculations. Artificial structure plates carved with Archimedean spiral slits are designed to produce two-component RSABs (TRSABs). It is found that the number of main lobes, rotational speed, and initial position of the TRSAB can be modulated by simply changing the number of arms, initial radius, and relative angle of the two sets of spirals. The experimental and numerical demonstrations confirm the ability of artificial structure plates to generate TRSABs. Finally, simulations are performed to calculate the acoustic radiation force on Rayleigh polydimethylsiloxane (PDMS) particles in a TRSAB. The work presented here could greatly benefit acoustic particle three-dimensional trapping and manipulation.

Analysis of acoustic field characteristics of mesoscale eddies throughout their complete life cycle

Mesoscale eddies exert a profound influence on oceanic temperature and salinity structures, thereby altering the ecological environment and acoustic propagation characteristics. Prior research on acoustic propagation beneath mesoscale eddy effects has predominantly concentrated on fragmented, snapshot-style analyses. In contrast, this study employs a holistic approach by integrating multi-source data to elucidate oceanic temperature and salinity structures, ultimately impacting their ecological environment and acoustic propagation. While the existing paper, this study adopts a more comprehensive and successional methodology. Through the amalgamation of multi-source data, this research introduces an innovative mesoscale eddy tracking algorithm and an enhanced Gaussian eddy model. Utilizing the BELLHOP ray theory model, this investigation scrutinizes the acoustic field characteristics of a cyclonic eddy and a typical anticyclonic eddy (CE-AE) pair exhibiting complete life cycles in the Northwest Pacific. The results reveal that the complete life cycles of mesoscale eddies substantially impact the acoustic field environment. As a CE intensifies, the convergence zone (CZ) distance diminishes, the CZ width expands, and the direct wave (DW) distance shortens. Conversely, an intensifying AE increases the CZ distance, contracts the CZ width, and prolongs the DW distance. This paper presents a quantitative analysis to delineate the critical factors influencing eddy life cycles, indicating that both eddy intensity and deformation parameters significantly affect acoustic propagation characteristics, with eddy intensity exerting a more substantial influence. This research substantially contributes to the application of sea surface altimetry data for underwater acoustic studies and provides preliminary insights into the impacts of eddy parameters on underwater acoustic propagation within typical mesoscale eddy environments. Moreover, this research offers a foundation for future investigations into the intricate relationships between eddy dynamics and acoustic propagation in oceanic systems.

Observation of a two-dimensional topological metal in acoustic metamaterials

A two-dimensional topological metal with anti-helical-like edge states has been predicted recently but has not been confirmed experimentally. In this paper, we report an experimental realization of this topological metal in acoustic metamaterial by introducing a time-reversal symmetry protected square lattice. The edge states appearing in gapless bulk bands are observed by measuring the projected dispersions and acoustic pressure field distributions. Moreover, these edge states propagate in the same direction when simultaneously exciting two sources with a fixed phase difference. Interestingly, by simply changing the coupling tubes, we realized the transformation of an acoustic topological metal to a topological insulator. Our work not only pushes forward the studies of topological metals but also inspires the design of multifunctional acoustic devices.

Multidimensional Particle Separation by Tilted-Angle Standing Surface Acoustic Waves—Physics, Control, and Design

Lab-on-a-Chip devices based on tilted-angle standing surface acoustic waves (tasSAWs) emerged as a promising technology for multidimensional particle separation, highly selective in particle size and acoustic contrast factor. For this active separation method, a tailored acoustic field is used to focus and separate particles on stationary pressure nodes by means of the acoustic radiation force. However, additional non-linear acoustofluidic phenomena, such as the acoustically induced fluid flow or dielectrophoretic effects, are superimposed on the separation process. To obtain a particle separation of high quality, control parameters that can be adjusted during the separation process as well as design parameters are available. The latter are specified prior to the separation and span a high-dimensional parameter space, ranging from the acoustic wavelength to the dimensions and materials used for the microchannel. In this paper, the physical mechanisms to control and design tasSAW-based separation devices are reviewed. By combining experimental, semi-analytical, and numerical findings, a critical channel height and width are derived to suppress the influence of the acoustically induced fluid flow. Dealing with the three-dimensional nature of the separation process, particles are focused at different height levels of equal force balance by implementing a channel cover of high acoustic impedance while achieving an approx. three-times higher acoustic pressure. Using this improved channel design, the particle shape is identified as an additional separation criterion, rendering the continuous acoustofluidic particle separation as a multidimensional technology capable of selectively separating microparticles below 10 μm with regard to size, acoustic contrast, and shape.

Mode-informed complex-valued neural processes for matched field processing.

A complex-valued neural process method, combined with modal depth functions (MDFs) of the ocean waveguide, is proposed to reconstruct the acoustic field. Neural networks are used to describe complex Gaussian processes, modeling the distribution of the acoustic field at different depths. The network parameters are optimized through a meta-learning strategy, preventing overfitting under small sample conditions (sample size equals the number of array elements) and mitigating the slow reconstruction speed of Gaussian processes (GPs), while denoising and interpolating sparsely distributed acoustic field data, generating dense field data for virtual receiver arrays. The predicted field is then integrated with the matched field processing (MFP) method for passive source localization. Validation on the SWellEx-96 waveguide shows significant improvements in localization performance and reduces sidelobes of ambiguity surface compared to traditional MFP and GP-based MFP. Moreover, the proposed kernel based on MDFs outperforms the Gaussian kernel in describing ocean waveguide characteristics. Because of the feature representation of multi-modal mapping, this kernel enhances acoustic field prediction performance and improves the accuracy and robustness of MFP. Simulated and real data are used to verify the validity.

Enhancing performance of lithium metal batteries through acoustic field application

The graphic illustrates how an external acoustic field stabilizes the SEI layer by enhancing lithium-ion mass transfer at slip lines and kinks, reducing pit formation and promoting a more uniform SEI, ultimately improving battery performance.

End-to-end underwater acoustic transmission loss prediction with adaptive multi-scale dilated network.

Underwater acoustic propagation is a complex phenomenon in the ocean environment. Traditional methods for calculating acoustic propagation loss rely on solving complex partial differential equations. Deep learning methods, leveraging their robust nonlinear approximation capabilities, can model various physical phenomena effectively, significantly reducing computation time and cost. Despite considerable advancements in the study of various inverse underwater acoustic problems, research focused on forward physical modeling is still nascent. This study proposes an end-to-end architecture for predicting underwater acoustic transmission loss (TL). This architecture employs a data-driven approach capable of swiftly and accurately predicting the complete acoustic field. It employs a U-Net model integrated with an adaptive multi-scale dilated module, named MultiScale-DUNet, which effectively predicts by assimilating multi-scale acoustic field information. It is demonstrated that the MultiScale-DUNet is capable of predicting acoustic TL in complex two-dimensional ocean environments within the end-to-end framework. The results indicate that the MultiScale-DUNet can rapidly predict the acoustic TL while maintaining high accuracy under computationally inexpensive conditions. This end-to-end technology for predicting underwater acoustic TL holds broad application prospects in fields such as underwater exploration and real-time underwater monitoring.

Acoustic Field Analysis of Ultrasonic Standing Wave Levator Based on Acoustic Flow Coupling Field

Acoustic Field Analysis of Ultrasonic Standing Wave Levator Based on Acoustic Flow Coupling Field

Experimental study on the translation behavior of an in-situ bubble pair in the ultrasonic field.

The dynamics of acoustic cavitation bubbles hold significant importance in ultrasonic cleaning, biomedicine, and chemistry. Utilizing an in-situ normal pressure bubble generation and observation system that was developed, this study examined the translational behavior of micrometer-scale normal pressure bubble pairs with initial radius ratio of 1:1 and 2:1 under ultrasonic field excitation. A velocity-distance curve was proposed to quantify the secondary Bjerknes forces during various interaction stages of the bubbles. The findings revealed that equal-sized bubbles underwent an acceleration phase, a deceleration phase, and a velocity jump phase during attraction in both strong and weak acoustic fields. In contrast, bubbles of unequal sizes, due to different oscillation frequencies, experienced multiple acceleration and deceleration phases, presenting asynchronous behaviors. The study further explored the effects of the initial bubble radius, shape oscillation, and volume oscillations on the attraction speed. Results showed that the velocity of the bubble's centroid decreased with an increase in the initial radius, while intensified volume oscillations increased the secondary Bjerknes force, thereby increasing the centroid's velocity. Moreover, strong acoustic fields were more likely to induce severe volume and shape oscillations in bubbles than weak fields. The irregular shape oscillations in twin bubbles resulted in shortened durations of acceleration and deceleration phases, reduced peak velocities of acceleration phase, and diminished acceleration during the velocity jump phase. The research provided some mechanical explanations for acoustic cavitation dynamics and its applications.

Research on acoustic temperature field hotspot tracking based on RBFNN adaptive grid

Research on acoustic temperature field hotspot tracking based on RBFNN adaptive grid