Article
Acoustics
Yafeng Chen, Jie Zhu, Zhongqing Su
Summary: This study designs four new types of second-order phononic topological insulators (SPTIs) with customized dual-bandgap, allowing for dual-band corner states and potential applications in multiband communications and manipulation of elastic waves with enhanced robustness.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Materials Science, Multidisciplinary
Xiaoying Zhuang, Chuong Nguyen, S. S. Nanthakumar, Ludovic Chamoin, Yabin Jin, Timon Rabczuk
Summary: This paper presents a methodology for inverse design of reconfigurable topological insulators in plate-like structures. By utilizing topology optimization and piezoelectric patches, the space inversion symmetry is broken, leading to the real-time reconfigurability of topological interfaces for waveguide applications.
MATERIALS & DESIGN
(2022)
Article
Chemistry, Physical
Nana Shumiya, Md Shafayat Hossain, Jia-Xin Yin, Zhiwei Wang, Maksim Litskevich, Chiho Yoon, Yongkai Li, Ying Yang, Yu-Xiao Jiang, Guangming Cheng, Yen-Chuan Lin, Qi Zhang, Zi-Jia Cheng, Tyler A. Cochran, Daniel Multer, Xian P. Yang, Brian Casas, Tay-Rong Chang, Titus Neupert, Zhujun Yuan, Shuang Jia, Hsin Lin, Nan Yao, Luis Balicas, Fan Zhang, Yugui Yao, M. Zahid Hasan
Summary: This study provides micro-spectroscopic evidence for the presence of a room-temperature quantum spin Hall edge state on the surface of a higher-order topological insulator. The research reveals the microstructural features of the topological phase and suggests further exploration of high-temperature transport quantization.
Article
Multidisciplinary Sciences
Jingyuan Zhong, Ming Yang, Zhijian Shi, Yaqi Li, Dan Mu, Yundan Liu, Ningyan Cheng, Wenxuan Zhao, Weichang Hao, Jianfeng Wang, Lexian Yang, Jincheng Zhuang, Yi Du
Summary: Weak topological insulators with tunable topological states are studied using ARPES and first-principles calculations. The authors find signatures of layer-selective quantum spin Hall channels in a candidate weak topological insulator, Bi4Br2I2, which is stacked by three different quantum spin Hall insulators. The energy gap at the crossing points of different Dirac cones, induced by interlayer interaction, enables the tunability of topological edge states. This work offers a perspective for constructing tunable quantized conductance devices for future spintronic applications.
NATURE COMMUNICATIONS
(2023)
Article
Computer Science, Interdisciplinary Applications
Yafeng Chen
Summary: In this study, topology optimized acoustic crystals were used to create second-order acoustic topological insulators (SATIs) hosting valley-selective corner states. By directly restricting the symmetry of the crystals and maximizing the band gap through topology optimization, better localized corner states were achieved.
STRUCTURAL AND MULTIDISCIPLINARY OPTIMIZATION
(2022)
Article
Multidisciplinary Sciences
Rui Wang, Tigran A. Sedrakyan, Baigeng Wang, Lingjie Du, Rui-Rui Du
Summary: Correlation and frustration are important in physics, leading to new quantum phases. In this study, we observe the moat-band phenomena in shallowly inverted InAs/GaSb quantum wells, where we find an unconventional time-reversal-symmetry breaking excitonic ground state. We demonstrate the evolution from helical-like to chiral-like edge transport and explain our experimental observations using a moat band for excitons that results from density imbalance.
Article
Engineering, Mechanical
Yafeng Chen, Fei Meng, Xiaodong Huang
Summary: This paper introduces a topology optimization approach for designing novel structures of acoustic topological insulators (TIs) and demonstrates the typical functionalities of acoustic TIs, verifying the effectiveness of the proposed method.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2021)
Article
Physics, Applied
Zhen Wang, Shiyuan Liu, Peilong Yuan, Xiaodong Xu
Summary: In this Letter, a bilayer elastic C-6v structure is proposed and used to manipulate two topological nontrivial valley pseudo-spin states. The transmission and prohibition of the elastic valley pseudo-spin states, as well as the tunneling between layers, can be flexibly controlled due to the interlayer polarization and mixing effects in the structure. The experimental results confirm the high transmission efficiency of elastic valley pseudo-spin states across layers, reaching 93%. This research expands and enriches the understanding of valley pseudo-spin states in the elastic environment and lays the foundation for the design of elastic topological devices.
APPLIED PHYSICS LETTERS
(2022)
Article
Materials Science, Multidisciplinary
Xuguang Wang, Daiyu Geng, Dayu Yan, Wenqi Hu, Hexu Zhang, Shaosheng Yue, Zhenyu Sun, Shiv Kumar, Eike F. Schwier, Kenya Shimada, Peng Cheng, Lan Chen, Simin Nie, Zhijun Wang, Youguo Shi, Yi-Qi Zhang, Kehui Wu, Baojie Feng
Summary: Experimental evidence of a 2DTI in the van der Waals material Ta2Pd3Te5 has been reported, showing that each monolayer is a 2DTI with weak interlayer interactions. Measurements confirm the existence of a band gap at the Fermi level and topological edge states inside the gap, making Ta2Pd3Te5 a promising material for fabricating spintronic devices based on the QSH effect.
Article
Materials Science, Multidisciplinary
T. Nathan Nunley, Side Guo, Liang-Juan Chang, David Lujan, Jeongheon Choe, Shang-Fan Lee, Fengyuan Yang, Xiaoqin Li
Summary: Recent research has found that thulium iron garnet (TmIG) based bilayers show promise in realizing small skyrmions at room temperature. By directly measuring the magnetic hysteresis loops, researchers have determined that the spin Hall topological Hall resistivity is considerably larger than previously estimated values. This finding further confirms the existence of skyrmions at room temperature and near-zero applied magnetic fields.
Article
Materials Science, Multidisciplinary
Kirill Plekhanov, Niclas Mueller, Yanick Volpez, Dante M. Kennes, Herbert Schoeller, Daniel Loss, Jelena Klinovaja
Summary: Theoretical study on second-order topological superconductors reveals a quadrupole spin polarization at system edges, offering a new signature for identifying topological phases. Experimental access to this feature can be achieved through spin-polarized scanning tunneling microscopes.
Article
Physics, Multidisciplinary
Shihao Zhang, Xi Dai, Jianpeng Liu
Summary: In this study, we theoretically investigate correlated insulator states and quantum anomalous Hall states in twisted multilayer graphene systems. We show that these systems can exhibit spin-polarized and valley-polarized insulator states under different interactions, and these states can be manipulated by external forces.
PHYSICAL REVIEW LETTERS
(2022)
Article
Acoustics
Hao-Wen Dong, Sheng-Dong Zhao, Rui Zhu, Yue-Sheng Wang, Li Cheng, Chuanzeng Zhang
Summary: This paper presents a bottom-up topology optimization approach for designing customized acoustic Dirac cones. Novel square-symmetric, chiral and orthogonal-symmetric sonic crystals with double, triple and quadruple degeneracies at different wavelength scales are constructed using this approach. The proposed methodology offers a unified framework for tailoring SCs with exotic functionalities.
JOURNAL OF SOUND AND VIBRATION
(2021)
Article
Chemistry, Physical
Marcio Costa, Gabriel R. Schleder, Carlos Mera Acosta, Antonio C. M. Padilha, Frank Cerasoli, Marco Buongiorno Nardelli, Adalberto Fazzio
Summary: The article introduces the discovery and application of higher-order topological insulators and explores the connection between spin Hall effect and HOTIs, proposing a new method to identify HOTIs by studying the spin Hall conductivity (SHC).
NPJ COMPUTATIONAL MATERIALS
(2021)
Article
Physics, Multidisciplinary
Jinfeng Zhao, Chenwen Yang, Weitao Yuan, Danmei Zhang, Yang Long, Yongdong Pan, Hong Chen, Zheng Zhong, Jie Ren
Summary: This study reports the observation of local elastic valley spin and the previously overlooked hidden elastic spin-valley locking mechanism. By controlling the elastic spin, the direction of valley phonon state transmission along the interface can be reversed. This discovery offers a new tool for exploring topological metamaterials.
PHYSICAL REVIEW LETTERS
(2022)
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
Acoustics
Yafeng Chen, Jie Zhu, Zhongqing Su
Summary: This study designs four new types of second-order phononic topological insulators (SPTIs) with customized dual-bandgap, allowing for dual-band corner states and potential applications in multiband communications and manipulation of elastic waves with enhanced robustness.
JOURNAL OF SOUND AND VIBRATION
(2023)
Article
Optics
Yafeng Chen, Zhihao Lan, Jie Zhu, Zhongqing Su
Summary: Photonic topological insulators offer efficient and robust manipulation of light. This study focuses on anisotropic topological edge states in two-dimensional photonic systems, considering both transverse magnetic (TM) and transverse electric (TE) modes. By using topology optimization, maximized odd-order band gaps are achieved in photonic crystals (PCs). An anisotropic topological phase transition is then induced, resulting in tightly localized anisotropic topological edge states at the interface of primitive and translated unit cells. Numerical simulations confirm the transmission properties of these anisotropic topological edge states. Our findings have implications for the development of reliable topological photonic devices.
OPTICS AND LASER TECHNOLOGY
(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
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, Applied
Lei Fan, Yafeng Chen, Shuowei An, Tuo Liu, Haiyan Fan, Jie Zhu, Zhongqing Su
Summary: A second-order elastic topological insulator (SETI) is created by etching a series of C-shaped slots on a metal plate, achieving dual-band topological corner states. The etched slots act as cantileverlike oscillators that couple with the flexural vibration modes of the plate, resulting in multiple locally resonant band gaps. The configuration of these slots on a C4v-symmetric lattice enables the creation of topologically distinct metastructures. The observation of the dual-band corner states in two broad topological band gaps simplifies the fabrication of metastructures for implementing locally resonant elastic topological insulators, benefiting applications such as elastic wave trapping and energy amplification at subwavelength scale.
PHYSICAL REVIEW APPLIED
(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
Engineering, Civil
Linwei Zhang, Zhonghao Bai, Qiang Zhang, Yao Jin, Yafeng Chen
Summary: This research investigates the vibration isolation performance and crashworthiness of a novel 3D lattice metamaterial, which utilizes a hollow rhombic dodecahedron and six cylindrical tubes as its unit cell. The presence of band gaps in this metamaterial can suppress the transmission of elastic waves, while its plastic deformation enables the absorption of crushing energy during collisions. The study examines the impact of structural parameters on the band gap features and crashing behaviors of the novel 3D metamaterial, highlighting the vital role of these parameters in achieving the desired vibration isolation and crashworthiness.
ENGINEERING STRUCTURES
(2023)
Article
Engineering, Mechanical
Yafeng Chen, Xueyun Wen, Zhongming Gu, Jie Zhu, Zhongqing Su
Summary: In this study, a topology optimization method is used to customize and optimize multiband second-order sonic topological insulators (SSTIs). Multiple dual-band SSTIs and a three-band SSTI with customizable bandgaps for hosting corner states are successfully constructed and experimentally validated. This research opens up a route for customizing high-performance multiband SSTIs, and the designed multiband SSTIs have the potential for designing robust multiband acoustic devices.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(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.
Article
Optics
Wai Chun Wong, Kai Ming Lau, Hong Liang, Tsz Kit Yung, Bei Zeng, Jensen Li
Summary: In this paper, we describe the quantum optical scattering of a linear dissipative metasurface using an equivalent Liouvillian dynamics. We demonstrate that the input-output relationship on the photon density matrix can be obtained by propagating the photon-moment matrix using a complete basis of the semiclassical Liouvillian superoperator. Our findings are important for characterizing quantum scattering of generally bianisotropic metasurfaces and for designing passive parity-time symmetric and non-Hermitian metasurfaces for quantum information processing applications.
Review
Nanoscience & Nanotechnology
Yafeng Chen, Zhihao Lan, Zhongqing Su, Jie Zhu
Summary: This article discusses the recent advances and achievements in the development of photonic and phononic topological insulators using inverse design methodologies. It covers one-dimensional TIs, TIs based on the quantum spin Hall effect and quantum valley Hall effect, as well as high-order TIs in lattices with diverse symmetries. Several inversely designed photonic and phononic TIs with superior performance are showcased, and the future of this emerging research field is also discussed.
Article
Nanoscience & Nanotechnology
Yafeng Chen, Zhihao Lan, Jie Zhu
Summary: This study proposes a new principle of second-order photonic topological insulators (SPTIs) and realizes second-order topological states in lattices with an odd number of sites. By topology optimization, second-order topological phases and highly localized corner states are successfully created within sizable band gaps. This offers a new route for exploring high-order topological states in photonics and other classical systems.
Article
Engineering, Mechanical
Xuanen Kan, Yanjun Lu, Fan Zhang, Weipeng Hu
Summary: A blade disk system is crucial for the energy conversion efficiency of turbomachinery, but differences between blades can result in localized vibration. This study develops an approximate symplectic method to simulate vibration localization in a mistuned bladed disk system and reveals the influences of initial positive pressure, contact angle, and surface roughness on the strength of vibration localization.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Zimeng Liu, Cheng Chang, Haodong Hu, Hui Ma, Kaigang Yuan, Xin Li, Xiaojian Zhao, Zhike Peng
Summary: Considering the calculation efficiency and accuracy of meshing characteristics of gear pair with tooth root crack fault, a parametric model of cracked spur gear is established by simplifying the crack propagation path. The LTCA method is used to calculate the time-varying meshing stiffness and transmission error, and the results are verified by finite element method. The study also proposes a crack area share index to measure the degree of crack fault and determines the application range of simplified crack propagation path.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Rongjian Sun, Conggan Ma, Nic Zhang, Chuyo Kaku, Yu Zhang, Qirui Hou
Summary: This paper proposes a novel forward calculation method (FCM) for calculating anisotropic material parameters (AMPs) of the motor stator assembly, considering structural discontinuities and composite material properties. The method is based on multi-scale theory and decouples the multi-scale equations to describe the equivalence and equivalence preconditions of AMPs of two scale models. The effectiveness of this method is verified by modal experiments.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Hao Zhang, Jiangcen Ke
Summary: This research introduces an intelligent scheduling system framework to optimize the ship lock schedule of the Three Gorges Hub. By analyzing navigational rules, operational characteristics, and existing problems, a mixed-integer nonlinear programming model is formulated with multiple objectives and constraints, and a hybrid intelligent algorithm is constructed for optimization.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Jingjing He, Xizhong Wu, Xuefei Guan
Summary: A sensitivity and reliability enhanced ultrasonic method has been developed in this study to monitor and predict stress loss in pre-stressed multi-layer structures. The method leverages the potential breathing effect of porous cushion materials in the structures to increase the sensitivity of the signal feature to stress loss. Experimental investigations show that the proposed method offers improved accuracy, reliability, and sensitivity to stress change.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Benyamin Hosseiny, Jalal Amini, Hossein Aghababaei
Summary: This paper presents a method for monitoring sub-second or sub-minute displacements using GBSAR signals, which employs spectral estimation to achieve multi-dimensional target detection. It improves the processing of MIMO radar data and enables high-resolution fast displacement monitoring from GBSAR signals.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Xianze Li, Hao Su, Ling Xiang, Qingtao Yao, Aijun Hu
Summary: This paper proposes a novel method for bearing fault identification, which can accurately identify faults with few samples under complex working conditions. The method is based on a Transformer meta-learning model, and the final result is determined by the weighted voting of multiple models.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Xiaomeng Li, Yi Wang, Guangyao Zhang, Baoping Tang, Yi Qin
Summary: Inspired by chaos fractal theory and slowly varying damage dynamics theory, this paper proposes a new health monitoring indicator for vibration signals of rotating machinery, which can effectively monitor the mechanical condition under both cyclo-stationary and variable operating conditions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Hao Wang, Songye Zhu
Summary: This paper extends the latching mechanism to vibration control to improve energy dissipation efficiency. An innovative semi-active latched mass damper (LMD) is proposed, and different latching control strategies are tested and evaluated. The latching control can optimize the phase lag between control force and structural response, and provide an innovative solution to improve damper effectiveness and develop adaptive semi-active dampers.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Menghao Ping, Xinyu Jia, Costas Papadimitriou, Xu Han, Chao Jiang, Wang-Ji Yan
Summary: Identification of non-Gaussian processes is a challenging task in engineering problems. This article presents an improved orthogonal series expansion method to convert the identification of non-Gaussian processes into a finite number of non-Gaussian coefficients. The uncertainty of these coefficients is quantified using polynomial chaos expansion. The proposed method is applicable to both stationary and nonstationary non-Gaussian processes and has been validated through simulated data and real-world applications.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Lei Li, Wei Yang, Dongfa Li, Jianxin Han, Wenming Zhang
Summary: The frequency locking phenomenon induced by modal coupling can effectively overcome the dependence of peak frequency on driving strength in nonlinear resonant systems and improve the stability of peak frequency. This study proposes the double frequencies locking phenomenon in a three degrees of freedom (3-DOF) magnetic coupled resonant system driven by piezoelectricity. Experimental and theoretical investigations confirm the occurrence of first frequency locking and the subsequent switching to second frequency locking with the increase of driving force. Furthermore, a mass sensing scheme for double analytes is proposed based on the double frequencies locking phenomenon.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Kai Ma, Jingtao Du, Yang Liu, Ximing Chen
Summary: This study explores the feasibility of using nonlinear energy sinks (NES) as replacements for traditional linear tuned mass dampers (TMD) in practical engineering applications, specifically in diesel engine crankshafts. The results show that NES provides better vibration attenuation for the crankshaft compared to TMD under different operating conditions.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Wentao Xu, Li Cheng, Shuaihao Lei, Lei Yu, Weixuan Jiao
Summary: In this study, a high-precision hydraulic mechanical stand and a vertical mixed-flow pumping station device were used to conduct research on cavitation signals of mixed-flow pumps. By analyzing the water pressure pulsation signal, it was found that the power spectrum density method is more sensitive and capable of extracting characteristics compared to traditional time-frequency domain analysis. This has significant implications for the identification and prevention of cavitation in mixed-flow pump machinery.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Xiaodong Chen, Kang Tai, Huifeng Tan, Zhimin Xie
Summary: This paper addresses the issue of parasitic motion in microgripper jaws and its impact on clamping accuracy, and proposes a symmetrically stressed parallelogram mechanism as a solution. Through mechanical modeling and experimental validation, the effectiveness of this method is demonstrated.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
Article
Engineering, Mechanical
Zhifeng Shi, Gang Zhang, Jing Liu, Xinbin Li, Yajun Xu, Changfeng Yan
Summary: This study provides useful guidance for early bearing fault detection and diagnosis by investigating the effects of crack inclination and propagation direction on the vibration characteristics of bearings.
MECHANICAL SYSTEMS AND SIGNAL PROCESSING
(2024)
