Article
Engineering, Mechanical
Hai D. Huynh, Xiaoying Zhuang, Harold S. Park, S. S. Nanthakumar, Yabin Jin, Timon Rabczuk
Summary: The Willis coupling, which couples momentum to strain in elastic metamaterials, has been extensively studied for its potential in enabling novel wave propagation phenomena. Recent work has shown that the momentum can also be coupled to electrical stimulus in piezoelectric composites, resulting in a new form of electro-momentum coupling. In this study, a topology optimization approach is presented to maximize the electro-momentum coupling in piezoelectric composites, allowing for the design of composites that support novel wave phenomena excited through non-mechanical means.
EXTREME MECHANICS LETTERS
(2023)
Article
Acoustics
Zhanyu Li, Hongfei Qu, Hongkuan Zhang, Xiaoning Liu, Gengkai Hu
Summary: Acoustic Willis materials exhibit unconventional coupling between pressure and velocity, enabling extraordinary control over the propagation of acoustic waves. This study predicts the existence of interfacial modes at the interface between two acoustic Willis materials, dependent on the relative orientations of the coupling vectors. Experimental results confirm the theory, showing good agreement with simulations and theoretical analysis.
Article
Engineering, Civil
Gioele Ruffini, Valentin Heller, Riccardo Briganti
Summary: This article investigates the effect of varying bathymetries on landslide-tsunamis and provides methods for predicting transformed wave characteristics. Through simulations of different idealized landslide-tsunamis and analysis using Artificial Neural Networks and regression, empirical equations for predicting transformed waves were developed. The study also demonstrated the efficient use of the developed prediction methods in accurately forecasting the 2014 Lake Askja landslide-tsunami compared to available numerical simulations.
COASTAL ENGINEERING
(2021)
Article
Oceanography
Olivier Kimmoun, Hung-Chu Hsu, Norbert Hoffmann, Amin Chabchoub
Summary: The study found that residual effects of four-wave resonance interactions in shallow regions affect the nonlinear group propagation over steep bottom topography slopes, while narrowing the spectrum of JONSWAP wave fields can improve consistency between the model and data.
Article
Geochemistry & Geophysics
Pavel Chernyshov, Teodor Vrecica, Sara Nauri, Yaron Toledo
Summary: This article presents a 2-D wavelet-based radar analysis method for sea surface reconstruction, which overcomes the limitations of Fourier analysis and has near real-time capabilities with lower errors.
IEEE TRANSACTIONS ON GEOSCIENCE AND REMOTE SENSING
(2022)
Article
Engineering, Electrical & Electronic
Ding Nie, Min Zhang, Pengbo Wei, Mingyuan Man
Summary: This article focuses on improving the understanding of electromagnetic scattering from water waves modulated by shoaling effects from different upslope submarine topography in the nearshore zone. Simulation results showed that the angular position and higher-order harmonics of the bistatic scattering coefficient are impacted by the upslope variations, as well as the wave height and nonlinear effects of the shallow water waves. Additionally, simulations support the transfer of wave energy from low to high-frequency components in the shallow water zone with upslope submarine topography.
IEEE JOURNAL OF SELECTED TOPICS IN APPLIED EARTH OBSERVATIONS AND REMOTE SENSING
(2021)
Article
Environmental Sciences
Jung-Eun Oh, Yeon S. S. Chang, Kyong Ho Ryu, Weon Mu Jeong
Summary: In this study conducted along the east coast of South Korea, it was found that the nearshore infra-gravity waves (IGWs) decrease in height with decreasing water depth, and they exhibit linear correlations with short waves (SWs). The wave energy flux was identified as the preferred parameter for describing the height of the IGWs. However, a comparison showed that the IGW height over the SW parameters was higher in sandy beaches than in rocky seabeds, suggesting that seabed conditions may play an important role in the process of IGW shoaling, although further evidence is needed.
FRONTIERS IN MARINE SCIENCE
(2023)
Article
Physics, Multidisciplinary
Xinhua Wen, Heung Kit Yip, Choonlae Cho, Jensen Li, Namkyoo Park
Summary: We propose a concept called acoustic amplifying diode that combines signal isolation and amplification in a single device. The signal is exponentially amplified in one direction with no reflection and perfectly absorbed in another direction. By using impedance matching, the device eliminates reflection in both directions and prevents backscattering to the signal source. We demonstrate the amplifying diode using an active metamaterial with nonreciprocal Willis coupling, and discuss the flexibility of implementation with the presence of both reciprocal and nonreciprocal couplings.
PHYSICAL REVIEW LETTERS
(2023)
Article
Engineering, Civil
Thomas Lykke Andersen, Mads Roge Eldrup
Summary: This paper discusses the separation of regular waves into incident and reflected components, both for linear and nonlinear waves on horizontal and sloping foreshores. By combining existing methods with a nonlinear shoaling model, the applicability range has been extended to mildly nonlinear reflected waves. The developed model's reliability is examined using numerical model data with varying foreshore slopes, wave nonlinearities, and reflection coefficients.
COASTAL ENGINEERING
(2021)
Article
Physics, Multidisciplinary
Liujun Xu, Guoqiang Xu, Jiaxin Li, Ying Li, Jiping Huang, Cheng-Wei Qiu
Summary: This study reports the development of spatiotemporal diffusive metamaterials by modulating thermal conductivity and mass density in heat transfer. The modified Fourier law after homogenizing spatiotemporal parameters demonstrates thermal Willis coupling between heat flux and temperature change rate. The directional and reversible asymmetric heat diffusion driven by thermal Willis coupling could have potential applications in directional diffusion and asymmetric manipulation of nonequilibrium mass and energy transfer.
PHYSICAL REVIEW LETTERS
(2022)
Article
Engineering, Ocean
Ranjodh Rai, Zhihua Ma, Zaibin Lin, Wei Bai, Ling Qian
Summary: This paper presents a stable method for solving the kinematic boundary condition equation in fully nonlinear potential flow models. The method is motivated by a total variation diminishing approach and is applicable to advection-dominated partial differential equations. It is simple, easily implemented, and produces accurate numerical solutions that agree well with experimental and analytical results.
APPLIED OCEAN RESEARCH
(2023)
Article
Multidisciplinary Sciences
Li Quan, Simon Yves, Yugui Peng, Hussein Esfahlani, Andrea Alu
Summary: Willis coupling in acoustics, which involves coupling between pressure and particle velocity, can be utilized for controlling and manipulating sound scattering through geometrically asymmetric structures.
NATURE COMMUNICATIONS
(2021)
Article
Engineering, Ocean
Masoud Hayatdavoodi, R. Cengiz Ertekin
Summary: The study investigates the diffraction and refraction of nonlinear shallow water waves due to uneven bathymetry using the Green-Naghdi (GN) equations in three dimensions. A numerical wave tank with various forms of three-dimensional bathymetry is created to simulate deep, transitional, and shallow regions. The results show good agreement with existing solutions for the wave surface elevation and particle velocities of solitary and cnoidal waves. The study also discusses the effects of nonlinearity and dispersion on wave diffraction and refraction, as well as the performance of the GN equations in solving these problems.
JOURNAL OF OFFSHORE MECHANICS AND ARCTIC ENGINEERING-TRANSACTIONS OF THE ASME
(2023)
Article
Multidisciplinary Sciences
Xian Zhou, Xiaofeng Gao, Mingjie Liu, Zirui Gao, Xuetao Qin, Wenhao Xu, Shitong Ye, Wenhua Zhou, Haoan Fan, Jing Li, Shurui Fan, Lei Yang, Jie Fu, Dequan Xiao, Lili Lin, Ding Ma, Siyu Yao
Summary: This study reported a light-driven dehydrogenative coupling reaction for highly selective and efficient synthesis of succinonitrile. The coupling reaction of acetonitrile into succinonitrile was achieved using anatase TiO2 supported Pt catalyst, and under optimized conditions, the selectivity to succinonitrile exceeded 97.5%. The mechanism study revealed that water acted as a cocatalyst in the reaction, assisting the cleavage of sp(3) C-H bond of acetonitrile. The synergy between TiO2 and Pt cocatalyst played an important role in enhancing selectivity and preventing over-oxidation and hydrolysis. This work offers an alternative and mild method for succinonitrile synthesis based on renewable energy, avoiding the use of toxic reagents and stoichiometric oxidative radical initiators.
NATURE COMMUNICATIONS
(2022)
Article
Acoustics
Xuanting Hao, Lian Shen
Summary: This study proposes a data-driven analysis framework based on the adaptive two-dimensional Hilbert-Huang transform for quantitatively characterizing the spatial variability of nearshore wave fields. Through simulations and calculations, the features of coastal wave processes including refraction, shoaling and breaking are investigated, and three integral quantities for characterizing wave fields are proposed.
Article
Nanoscience & Nanotechnology
Tsz Kit Yung, Hong Liang, Jiawei Xi, Wing Yim Tam, Jensen Li
Summary: The study presents a method for Jones matrix imaging based on two-photon interference. By using a reference metasurface and measuring the interference between the reference and an unknown object, the polarization responses of the object can be obtained at pixel level. The parallelization of optical measurements in this approach eliminates the need for switching the incident polarization, and takes advantage of the parallelization prevalent in any quantum algorithms.
Article
Physics, Applied
Kun Tang, Eitam Luz, David Amram, Luna Kadysz, Sebastien Guenneau, Patrick Sebbah
Summary: In this study, the practical realization of a unidirectional invisibility cloak for flexural waves using an area-preserving coordinate transformation is proposed. Time-resolved experiments and three-dimensional full-elasticity simulations demonstrate the effectiveness of the cloak in deviating pulsed plane waves and recombining the initial wavefront.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Yan Meng, Shuxin Lin, Bin-jie Shi, Bin Wei, Linyun Yang, Bei Yan, Zhenxiao Zhu, Xiang Xi, Yin Wang, Yong Ge, Shou-qi Yuan, Jingming Chen, Gui-Geng Liu, Hong-xiang Sun, Hongsheng Chen, Yihao Yang, Zhen Gao
Summary: For the classification of topological phases of matter, the consideration of whether a system is spinless or spinful is important. Recently, it has been theoretically realized that the algebraic structure of symmetries can be projectively represented in the presence of gauge symmetry, which enables the switch between spinless and spinful topological phases. In this study, spinful topological phases are experimentally demonstrated in spinless acoustic crystals with projective space-time inversion symmetry. This allows for the realization of a one-dimensional topologically gapped phase characterized by a 21 winding number, with double-degenerate bands in the entire Brillouin zone and two pairs of degenerate topological boundary modes.
PHYSICAL REVIEW LETTERS
(2023)
Article
Physics, Applied
Patrick C. Chaumet, Sebastien R. L. Guenneau
Summary: In this study, we investigate the electromagnetic forces and torques experienced on both perfect and discretized transformation-based concentrators under time-harmonic illumination. We compare the effect of the concentration to that of a perfect cloak. Furthermore, we examine the influence of a Lorentz dispersion model on the optical force and torque, and analyze the force experienced by a dielectric particle located at the center of the concentrator.
APPLIED PHYSICS LETTERS
(2023)
Article
Physics, Multidisciplinary
Xinhua Wen, Heung Kit Yip, Choonlae Cho, Jensen Li, Namkyoo Park
Summary: We propose a concept called acoustic amplifying diode that combines signal isolation and amplification in a single device. The signal is exponentially amplified in one direction with no reflection and perfectly absorbed in another direction. By using impedance matching, the device eliminates reflection in both directions and prevents backscattering to the signal source. We demonstrate the amplifying diode using an active metamaterial with nonreciprocal Willis coupling, and discuss the flexibility of implementation with the presence of both reciprocal and nonreciprocal couplings.
PHYSICAL REVIEW LETTERS
(2023)
Article
Multidisciplinary Sciences
Yuqiong Cheng, Kayode Adedotun Oyesina, Bo Xue, Dangyuan Lei, Alex M. H. Wong, Shubo Wang
Summary: This paper demonstrates both theoretically and experimentally that the synergy of chirality and anisotropy can produce three different directional dipoles in one structure. By selecting different faces, selective manipulation of optical directionality can be achieved. This structure enables high-dimensional control of both near-field and far-field directionality, with broad applications in various fields such as photonic integrated circuits, quantum information processing, and subwavelength-resolution imaging.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2023)
Article
Physics, Multidisciplinary
Richard Craster, Sebastien Guenneau, Muamer Kadic, Martin Wegener
Summary: Mechanical metamaterials, designed composites with elastic behaviors and effective mechanical properties beyond those of their individual ingredients, have made significant progress in the last decade due to advances in computational science and manufacturing. This review provides a tutorial on its mathematical basis and summarizes the state-of-the-art in both conceptual and experimental aspects.
REPORTS ON PROGRESS IN PHYSICS
(2023)
Article
Acoustics
Michele Brun, Sebastien Guenneau
Summary: This paper analyzes the elastic properties of a class of cylindrical cloaks derived from linear geometric transforms x -> x', which can exhibit neutral, mirage, or field confinement effects. The study reveals that achieving these effects requires specific combinations of elastic and density tensors with positive or negative definiteness.
Article
Materials Science, Multidisciplinary
Jiawei Xi, Jian Shen, Man To Chow, Tan Li, Jack Ng, Jensen Li
Summary: Multiplexing holography combined with metasurfaces using different degrees of light freedom has provided new applications in display and information processing. Polarization-multiplexed holograms can store the maximum amount of information, but it requires using bianisotropic metasurfaces instead of conventional single-layer nanostructures, which complicates the design and generation of holograms. In this study, an integrated neural network approach is developed to directly obtain metasurface profiles from independent holograms, allowing for complex polarization holograms without detailed knowledge of physical constraints.
ADVANCED OPTICAL MATERIALS
(2023)
Article
Physics, Multidisciplinary
Hong Liang, Hammad Ahmed, Wing Yim Tam, Xianzhong Chen, Jensen Li
Summary: In this study, a geometric phase metasurface is used to remotely and continuously control the vortex states of a heralded photon. Metasurfaces, which utilize engineered nanostructures, offer control over different dimensions of light and have versatile applications. By selecting the polarization of the heralding photon, the orbital angular momentum (OAM) of the signal photon can be remotely controlled. This research has important implications for quantum communication and information processing.
COMMUNICATIONS PHYSICS
(2023)
Article
Multidisciplinary Sciences
Xiang Xi, Bei Yan, Linyun Yang, Yan Meng, Zhen-Xiao Zhu, Jing-Ming Chen, Ziyao Wang, Peiheng Zhou, Perry Ping Shum, Yihao Yang, Hongsheng Chen, Subhaskar Mandal, Gui-Geng Liu, Baile Zhang, Zhen Gao
Summary: The authors report the first experimental observation of topological antichiral surface states in a magnetic Weyl photonic crystal by constructing a modified Haldane model. Antichiral surface states, the two-dimensional extension of one-dimensional antichiral edge states, have never been realized in any physical system before. The unique properties of antichiral surface states, including antichiral robust propagation and a single open Fermi arc connecting two projected Weyl points, have been directly observed in this study.
NATURE COMMUNICATIONS
(2023)
Article
Materials Science, Multidisciplinary
Qing Tong, Jensen Li, Shubo Wang
Summary: This research investigates the circular dichroism effect in acoustic systems. It is found that the effect is negligible in lossy metamaterials with C4 rotational symmetry but can be strongly enhanced in C2-symmetric systems with inhomogeneous loss. This enhancement is attributed to the presence of polarization band gaps and non-Hermitian exceptional points.
Article
Nanoscience & Nanotechnology
Pengfei Zhao, Liyou Luo, Yongquan Liu, Jensen Li
Summary: This study develops a transformation theory for manipulating the illusion effects of flexural waves. By introducing tailor-made thickness profiles on different curved shapes, the flexural waves can propagate in a way that is different from the actual configuration. Numerical simulations and experimental mapping confirm the effectiveness of this approach and reveal its potential applications in structural designs.
Article
Materials Science, Multidisciplinary
Xinghon Zhu, Hong-Wei Wu, Yu Zhuo, Zilin Liu, Jensen Li
Summary: This study establishes the temporal effective medium theory for acoustic metamaterials with time-varying frequency dispersion for compressibility. The formulas for the effective medium vary with different modulation parameters and the transition between dispersive and nondispersive regimes. The results have potential applications in designing temporal functional devices in classical waves such as acoustics, elastodynamics, and electromagnetism.