Metamaterials can be engineered to exhibit properties not typically found in nature, including asymmetric transmission and surface-wave cloaking. Researchers show that metamaterials also yield acoustic one-way cloaks.

Significance Acoustic communication is critical for underwater application such as deep-ocean scientific explorations and off-shore industrial controls. This because other techniques using electromagnetic waves are difficult applications due to the strong absorption of water. Optical communication, on hand, suffers from light scattering, making long-range optical very challenging. Therefore, acoustic transmit information currently dominant technique applications. However, low-frequency...

Parity-time (PT) symmetric systems experience phase transition between PT exact and broken phases at exceptional point. These transitions contribute significantly to the design of single mode lasers, coherent perfect absorbers, isolators, diodes. However, such points are extremely difficult access in practice because dispersive behaviour most loss gain materials required systems. Here we introduce a method systematically tame these control phases. Our experimental demonstration hinges on an...

Abstract Zero index materials where sound propagates without phase variation, holds a great potential for wavefront and dispersion engineering. Recently explored electromagnetic double zero metamaterials consist of periodic scatterers whose refractive is significantly larger than that the surrounding medium. This requirement fundamentally challenging airborne acoustics because speed (inversely proportional to index) in air among slowest. Here, we report first experimental realization an...

This paper provides a tutorial and summary of the theory circulant matrices their application to modeling analysis free forced vibration mechanical structures with cyclic symmetry. Our presentation basic is distilled from classic book Davis (1979, Circulant Matrices, 2nd ed., Wiley, New York) results, proofs, examples geared specifically applications. aim collect most relevant results existing in single paper, couch mathematics form that accessible vibrations analyst, provide highlight key...

Unlike optical waves, acoustic waves in fluids are described by scalar pressure fields, and therefore considered spinless. Here, we demonstrate experimentally the existence of spin acoustics. In interference two propagating perpendicularly to each other, observed angular momentum free space as a result rotation local particle velocity. We successfully measured spin, spin-induced torque acting on designed lossy probe that results from absorption momentum. The is also evanescent field guided...

A sound demonstration of Klein tunneling The ability particles to tunnel through barriers is an important property quantum mechanical systems, and the extent effect strongly dependent on properties barrier. By contrast, can exhibit unity transmission that independent width height energy barrier, but direct evidence for this remains elusive. Using a phononic system comprising periodic array dielectric pillars, Jiang et al. provide observation tunneling. Near-unity acoustic excitations was...

Recently developed metasurfaces have been used for surface engineering applications. However, the ability to cloak or mimic reflective surfaces with a large in-plane phase gradient remains unexplored. One major challenge is that even small incidence angle, strong acoustic impedance variation induced by random height profile creates additional scattering and increases complexity of analysis design metasurface. Here, we introduce an metasurface 1/12 wavelength thickness realize carpet randomly...

Aiming at the problem of path planning algorithm autonomous parade robot in indoor environment, this paper, based on Dijkstra and A∗ algorithm, introduces influence current node's parent node to heuristic function seeks optimal weight optimize algorithm. In MATLAB different scenarios were simulated, compared with non-improved situation terms searching consumption time, cost traversed grid number other indexes. After using more reasonable changing appropriately, poor real-time capacity was...

Acoustic communication is crucial in underwater exploration, where sound the dominant information carrier, with significantly less loss and scattering than that of electromagnetic waves. However, capacity acoustic channels limited due to intrinsically low speed relative waves because attenuation increases frequency. Recently, orbital angular momentum (OAM) has emerged as an alternative multiplexing degree freedom encode data onto vortex beams for increasing communication. For retrieval from...

This research aims to demonstrate a novel vortex ultrasound enabled endovascular thrombolysis method designed for treating cerebral venous sinus thrombosis (CVST). is topic of substantial importance since current treatment modalities CVST still fail in as many 20% 40% the cases, and incidence has increased outbreak coronavirus disease 2019 pandemic. Compared with conventional anticoagulant or thrombolytic drugs, sonothrombolysis potential remarkably shorten required time owing direct clot...

Ultrasound localization microscopy (ULM) had made it possible to differentiate microbubble contrast agents that are separated only by a few micrometers and, thus, opening the path for super-resolution imaging. However, due innate limits of acoustic waves and imaging, similar levels resolution optical imaging (i.e., submicron resolution) still very challenging. In this paper, we utilize ULM achieve cellular using phase-change perfluorocarbon nanodroplets (PFCnDs) as agent were fabricated with...

Abstract This article studies the nonreciprocity of a system that consists bistable element coupled to monostable through contactless magnetic interaction. To illustrate concept, is physically realized using pendulum interacts with stationary magnet and classical pendulum. A numerical model implemented simulate nonlinear dynamics system. Both simulations experiments show exhibits strong amplitude-dependent in response initial excitations. At small input amplitudes, has an intrawell minimal...

A recent work introduces the problem of learning set functions from data generated by a so-called optimal subset oracle. Their approach approximates underlying utility function with an energy-based model, whose parameters are estimated via mean-field variational inference. This approximation reduces to fixed point iterations; however, as number iterations increases, automatic differentiation quickly becomes computationally prohibitive due size Jacobians that stacked during backpropagation....

Genetically encoded imaging reporters are critical tools for tracking cell fate and function in regenerative medicine. Gas vesicles (GVs), air-filled protein nanostructures derived from bacteria, offer unique advantages noninvasive due to their acoustic optical properties. In this study, we engineered human pluripotent stem cells (hPSCs) express GVs using a doxycycline-inducible system. Upon doxycycline (Dox) treatment, formed intracellularly enabled enhanced contrast both ultrasound...

Bianisotropic gratings offer superior control of airborne sound via asymmetric wave transmission and reflection at an arbitrarily designed angle, leading to better technology in acoustic lensing, noise control, high-intensity focused ultrasound therapies. Traditional bianisotropic materials depend on the resonance deeply subwavelength particles, with intrinsic loss that limits grating efficiency. This study designs elements using a finite-element method maximize scattering efficiency,...

Active acoustic metamaterials incorporate electric circuit elements that input energy into an otherwise passive medium to aptly modulate the effective material properties. Here, we propose active metamaterial with Willis coupling drastically extend tunability of density and bulk modulus accessible parameter range enlarged by at least two orders magnitude compared a non-Willis metamaterial. Traditional designs are based on local resonances without considering limit their range. Our design...

Perfluorocarbon nanodroplets (PFCnDs) are ultrasound contrast agents that phase-transition from liquid to gas microbubbles when activated by laser irradiation or insonated with an pulse. The dynamics of PFCnDs can vary drastically depending on the nanodroplet composition, including lipid shell properties. In this paper, we investigate effect varying ratio PEGylated non-PEGylated phospholipids in outer acoustic vaporization (liquid phase transition) and inertial cavitation (rapid collapse...

The formation and propagation of acoustic vortex waves have been increasing interest for multiple applications, namely, underwater communications. Several methods presented to form these vortices in environments; however, their performance over long distances is largely unstudied. Understanding the long-distance vital enhancing usefulness as an added degree freedom communications systems. In this work, ray tracing algorithm bellhop used investigate design parameters wave transducer receiver...