Article
Engineering, Mechanical
Shujin Yuan, Yi Sun, Min Wang, Jiheng Ding, Jinglei Zhao, Yining Huang, Yan Peng, Shaorong Xie, Jun Luo, Huayan Pu, Fuqiang Liu, Long Bai, Xiao-Dong Yang
Summary: This paper proposes a vibration isolator based on a tunable negative stiffness mechanism, which combines the advantages of high-static low-dynamic stiffness isolators and variable stiffness isolators. The use of a novel tunable negative stiffness spring using Maxwell normal stress results in significantly improved stiffness tunable range and energy utilization efficiency due to the newly designed magnetic circuit. Experimental results demonstrate that the device can produce online tunable negative stiffness, expanding the isolation bandwidth and significantly improving vibration isolation performance.
INTERNATIONAL JOURNAL OF MECHANICAL SCIENCES
(2021)
Article
Optics
Min Zhou, Zhe Zhang, Laipeng Shao, Shen Liu, Yu Liu, Yu Pang, Zhiyong Bai, Cailing Fu, Wei Cui, Lin Qi, Yiping Wang
Summary: A broadband tunable orbital angular momentum (OAM) mode converter based on a helical long-period fiber grating inscribed in a conventional single-mode fiber has been experimentally demonstrated in this study, showing wide bandwidth and dynamic tunability within a large dynamic range.
Article
Instruments & Instrumentation
Changlang Wu, Chenxi Peng, Tu C. Le, R. Das, Phuong Tran
Summary: The paper proposes a class of tunable metamaterials that use inclined beams to achieve instability in a rigid system. The effects of different beam tilt angles on structural stiffness and buckling load are evaluated through experiments and simulations. The results show that the inclination angle of the tilted beams has a positive correlation with the structural properties. A design plot is provided to predict and tune the snap-through behavior of multiple-layered structures via beam angles and unit-cell arrangements.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Nanoscience & Nanotechnology
Zhenzhen Shen, Chunchi Zhang, Yajing Meng, Zegao Wang
Summary: The interaction between molybdenum disulfide (MoS2) and light is investigated in this study, with the aim of constructing highly integrated optoelectronics in communication and wearable healthcare. The researchers fabricate a MoS2-based phototransistor using polyvinylidene fluoride and 1-ethyl-3-methyl-imidazolium bis(trifluoromethylsulfonyeimide) ion-gel as a replacement for oxide. They find that the photoelectrical effect of the phototransistor can be greatly tuned by the gate voltage, resulting in a large tunability of carrier concentration. By tuning the carrier concentration, the photoresponse can be extended from the visible region to the short infrared region.
ACS APPLIED MATERIALS & INTERFACES
(2022)
Article
Engineering, Mechanical
Yuyang Chai, Jing Bian, Meng Li
Summary: This paper proposes a novel linkage anti-vibration structure (LAVS) with a linear positive and negative stiffness compensation mechanism for low-frequency vibration isolation. The static stiffness behavior is investigated, and by tuning structural parameters, the linear spring can completely compensate the linear negative stiffness to achieve enhanced quasi-zero stiffness. Numerical simulations and analysis demonstrate the effectiveness of the presented stiffness compensation mechanism.
NONLINEAR DYNAMICS
(2023)
Article
Engineering, Civil
Jing Bian, Xuhong Zhou, Ke Ke, Michael C. H. Yam, Yuhang Wang, Zi Gu, Miaojun Sun
Summary: This study proposes a passive prismatic-shaped isolation platform (PIP) to achieve enhanced quasi-zero stiffness (QZS) effect. The design concept uses a horizontal spring to generate tunable negative stiffness and installs oblique springs inside the cells of the prismatic structure to provide tunable positive stiffness, thus achieving the QZS effect by combining the negative and positive stiffness.
SMART STRUCTURES AND SYSTEMS
(2023)
Article
Optics
Isa Mazraeh-Fard, Abbas Alighanbari
Summary: This paper presents an equivalent circuit model for a graphene-based high-efficiency tunable broadband THz polarizer. Closed-form design formulas are derived based on the conditions for linear-to-circular polarization conversion in the transmission mode. The key structural parameters of the polarizer are directly calculated using this model according to target specifications. The proposed model is rigorously validated and found to be accurate and effective, accelerating the analysis and design processes. It offers a further step in developing a high-performance and controllable polarization converter with potential applications in imaging, sensing, and communications.
Article
Instruments & Instrumentation
Yuhuai Wang, Jian Yang, Zexin Chen, Yu Lin, Liping Gong, Shiwu Zhang, Weihua Li, Shuaishuai Sun
Summary: This study proposed and investigated a semi-active graded magnetorheological elastomer (MRE) metamaterial sandwich beam (GMREMSB) with real-time tunable graded stiffness to broaden the local resonant band gap. The theoretical calculation and experimental test showed that the bandwidth of the proposed GMREMSB can be widened by arranging the graded stiffness in ascending order. The experimental band gap under the graded current of 0.0-0.5-1.0 A was 6.4 Hz wider than the band gap of the periodic structure with single current of 0.0 A and 5.0 Hz wider than that of 1.0 A, with growth rates of 15.06% and 11.39%, respectively.
SMART MATERIALS AND STRUCTURES
(2023)
Article
Multidisciplinary Sciences
Guolin Yun, Tim Cole, Yuxin Zhang, Jiahao Zheng, Shuaishuai Sun, Yiming Ou-yang, Jian Shu, Hongda Lu, Qingtian Zhang, Yongjing Wang, Duc Pham, Tawfique Hasan, Weihua Li, Shiwu Zhang, Shi-Yang Tang
Summary: Reported the development of an electro-mechano responsive Field's metal hybrid elastomer with variable conductivity and stiffness, which can be applied in soft robotics and electronic devices. This material demonstrates significant improvements in performance compared to existing approaches and has potential applications in resilient robotic systems, intelligent instruments, and flexible electronics.
Article
Engineering, Civil
Dida Wang, Xi Wang, Yang Zhang, Tao Wang, Guoqiang Fu, Caijiang Lu
Summary: This paper focuses on optimizing the parameters of an electromagnetic vibration absorber to control low and variable frequency vibrations, leading to improved performance. The simulations and experiments demonstrate the effectiveness of the optimized absorber in controlling vibrations within a wide low-frequency range.
INTERNATIONAL JOURNAL OF STRUCTURAL STABILITY AND DYNAMICS
(2022)
Article
Engineering, Electrical & Electronic
Lejing Pi, Pengfei Wang, Shi-Jun Liang, Peng Luo, Haoyun Wang, Dongyan Li, Zexin Li, Ping Chen, Xing Zhou, Feng Miao, Tianyou Zhai
Summary: In this study, we demonstrate a palladium diselenide/molybdenum ditelluride van der Waals photovoltaic heterostructure that can provide simultaneous broadband image sensing and convolutional processing. The band alignment of the heterojunctions is tunable, and the devices show linear relationships between light intensity and photoconductivity, as well as between gate voltage and broadband photoresponse. Our in-sensor broadband convolutional processing improves recognition accuracy for multi-band images compared with conventional single-band-based convolutional neural networks.
NATURE ELECTRONICS
(2022)
Article
Optics
Xufend Jing, Guihong Qin, Peng Zhang
Summary: This study proposes a multi-functional metamaterial absorber based on doped silicon, which achieves broadband absorption through resonance and impedance matching, and precise amplitude control by controlling the pump luminous flux. By replacing the medium-doped silicon material with highly doped silicon material and combining it with microfluidic control, a high sensitivity sensor is realized. Experimental verification demonstrates the potential of this absorber in sensing applications.
PHOTONICS RESEARCH
(2022)
Article
Materials Science, Multidisciplinary
Lavinia Ghirardini, Eva A. A. Pogna, Giancarlo Soavi, Andrea Tomadin, Paolo Biagioni, Stefano Dal Conte, Sandro Mignuzzi, Domenico De Fazio, Takashi Taniguchi, Kenji Watanabe, Lamberto Duo, Marco Finazzi, Marco Polini, Andrea C. Ferrari, Giulio Cerullo, Michele Celebrano
Summary: Graphene is an ideal material for integrated nonlinear optics, with applications in broadband light emitters. By tuning the emission wavelength and bandwidth of graphene's broadband hot carrier photoluminescence and achieving thermal management through out-of-plane heat transfer to hexagonal boron nitride, we pave the way for graphene-based ultrafast broadband light emitters with tunable emission.
Article
Optics
Huan Guan, Feifei Ren, Shuhui Liang, Jinxin Gu, Chenchen Geng, Hang Wei, Shuliang Dou, Jiupeng Zhao, Yao Li
Summary: This study demonstrates that combining the insulator-to-metal transition of vanadium dioxide (VO2) with anti-reflection layers enables high and broadband open-state transmittance, while maintaining a large turndown ratio. Optothermal simulation shows that the transition of VO2 OL occurs at 0.23 μs under ultrafast laser irradiation with an intensity of 90 kW cm(-2). These findings provide a promising alternative to optical limiters in various technologies, from sensor protection to human eye defense.
LASER & PHOTONICS REVIEWS
(2023)
Article
Optics
Chih-Peng Chu, Kanglin Xiong, Jiagui Feng, Hui Yang
Summary: This paper proposes a universal magnetic-free scheme to achieve phase nonreciprocity. The scheme only requires two tunable phase shifters and a proper length of the delay line. Signals passing through the two phase shifters acquire the same phase shift in the forward direction, but different phase shifts in the backward direction. The scheme can be easily applied to other platforms such as rf communication systems and nanophotonics.
Article
Acoustics
Cailiang Zhang, Zhihui Lai, Zhisheng Tu, Hanqiu Liu, Yong Chen, Ronghua Zhu
Summary: This paper proposes two single-parameter-adjusting SR models to optimize the output performance of SR systems. The effects of the proposed models on SR output under different parameters and signals are investigated through numerical simulations, and their feasibility is verified through experimental results. The research results are of great significance for guiding the design of tri-stable SR models and the application of SR-based signal processing in the context of big data.
Article
Acoustics
Shaoqiong Yang, Hao Chang, Yanhui Wang, Ming Yang, Tongshuai Sun
Summary: In this study, a suspension system based on phononic crystals is designed for vibration isolation of acoustic loads in underwater gliders. The vibration properties of the phononic crystals and the effects of physical parameters on the underwater attenuation zones are investigated. Vibration tests show that the phononic crystal suspension system has a stable vibration isolation effect in the frequency range of 120-5000 Hz.
Article
Acoustics
Xuebin Zhang, Jun Zhang, Tao Liu, Ning Hu
Summary: This study proposes a tunable metamaterial beam to isolate flexural waves. A genetic algorithm-based size optimization is used to obtain a broad low-frequency bandgap. The tunability of the beam is achieved by attaching different numbers of permanent magnets to change the mass of the resonators. Additionally, ultra-broadband flexural wave attenuation is achieved by forming a gradient metamaterial beam based on the rainbow effect. Numerical and experimental results confirm the good flexural wave attenuation ability of the proposed beam.
Article
Acoustics
Luca Rapino, Francesco Ripamonti, Samanta Dallasta, Simone Baro, Roberto Corradi
Summary: This paper presents a method for simulating tyre/road noise using equivalent monopoles, including the synthesis of monopoles through an inverse problem approach and the use of an ISO 10844 road replica for laboratory testing. The method combines acoustic finite element models and numerical simulations of vehicles, and the results are validated by comparing them with measured data.
Article
Acoustics
Xiaoyan Zhu, Tin Oberman, Francesco Aletta
Summary: This paper explores the definition of acoustical heritage and proposes a multidimensional definition based on interviews with experts and detailed analysis of the data.
Article
Acoustics
Faeez Masurkar, Saurabh Aggarwal, Zi Wen Tham, Lei Zhang, Feng Yang, Fangsen Cui
Summary: This research focuses on estimating the elastic constants of orthotropic laminates using ultrasonic guided waves and inverse machine learning models. The results show that this approach has the potential to accurately predict the elastic constants of a material and reduce computational time.
Article
Acoustics
Feng Xiao, Haiquan Liu, Jia Lu
Summary: Diagnostic methods for cardiovascular disease based on heart sound classification have been widely studied due to their noninvasiveness, low-cost, and high efficiency. However, existing research often faces challenges such as the nonstationarity and complexity of heart sound signals, leading to limited capability of neural networks to extract discriminative features. To address these issues, this study proposes a novel convolutional neural network that combines 1D convolution and 2D convolution, and introduces an attention mechanism to enhance feature extraction capability. The study also explores the advantages and disadvantages of combining deep learning features with manual features, and adopts an evolving fuzzy system for decision-making interpretability.
Article
Acoustics
Hong Xu, Zhengyao He, Qiang Shi, Yushi Wang, Bo Zhang
Summary: This paper presents the development of a directional segmented ring transmitting transducer that can radiate sound waves in any horizontal region. The study focuses on the structure of the segmented ring transducer, its radiation sound field characteristics, and the beam pattern control method based on modal synthesis. The authors propose orthogonal beam pattern functions for adjusting steering angles and establish a three-dimensional finite element model to simulate the transmitting beam patterns. Experimental measurements and tests validate the effectiveness of the proposed transducer, showcasing its ability to steer the beam patterns to different directions.
Article
Acoustics
Jirui Yang, Shefeng Yan, Di Zeng, Gang Tan
Summary: This paper proposes an improved domain adaptation framework, self-supervised learning minimax entropy, to enhance the recognition performance of underwater target recognition models. The experimental results demonstrate that applying domain adaptation methods can effectively improve the recognition accuracy of the models under various marine conditions.
Article
Acoustics
Zonghan Sun, Jie Tian, Yuhang Zheng, Xiaocheng Zhu, Zhaohui Du, Hua Ouyang
Summary: This paper analyzes the noise reduction method of installing a sinusoidal-shaped inlet duct on a cooling fan through theoretical and experimental analysis of the acoustic mode modulation. The study establishes the correlation between the free field noise and acoustic mode of the fan rotor and the unsteady forces on the rotor blade surface. The results show that the sinusoidal-shaped inlet duct achieves greater noise reduction compared to a straight duct, especially at the blade passing frequency and its first harmonic.
Article
Acoustics
Min Li, Rumei Han, Hui Xie, Ruining Zhang, Haochen Guo, Yuan Zhang, Jian Kang
Summary: This study is part of a global collaboration to translate and standardise soundscape research. A reliable questionnaire for soundscape characterisation in Mandarin Chinese was developed and validated. The study found that salient sound sources become the focus of attention for individuals in urban open spaces, and the perception is also influenced by the acoustic characteristics of the soundscape. Certain types of sound sources play a more important role in soundscape perception.
Article
Acoustics
Arezoo Talebzadeh, Dick Botteldooren, Timothy Van Renterghem, Pieter Thomas, Dominique Van de Velde, Patricia De Vriendt, Tara Vander Mynsbrugge, Yuanbo Hou, Paul Devos
Summary: This study proposes a sound selection methodology to enhance the soundscape in nursing homes and reduce BPSD by analyzing sound characteristics and recognition methods. The results highlight the sound characteristics that lead to positive responses, while also pointing out the need for further studies to understand which sounds are most suitable for people with dementia.
Article
Acoustics
Yang Yang, Yongxin Yang, Zhigang Chu
Summary: This paper introduces a grid-free compressive beamforming method compatible with arbitrary linear microphone arrays, and demonstrates the correctness and superiority of the proposed method through examples. Monte Carlo simulations are performed to reveal the effects of source coherence, source separation, noise, and number of snapshots.
Article
Acoustics
Sukru Selim Calik, Ayhan Kucukmanisa, Zeynep Hilal Kilimci
Summary: Computer-Aided Language Learning (CALL) is growing rapidly due to the importance of acquiring proficiency in multiple languages for effective communication. In the field of CALL, the detection of mispronunciations is vital for non-native speakers. This research introduces a novel framework using audio-centric transformer models to detect mispronunciations in Arabic phonemes. The results demonstrate that the UNI-SPEECH transformer model yields notable classification outcomes in Arabic phoneme mispronunciation detection. The comprehensive comparison of these transformer models provides valuable insights and guidance for future investigations in this domain.
Article
Acoustics
Yi-Yang Ni, Fei-Yun Wu, Hui-Zhong Yang, Kunde Yang
Summary: This paper proposes an improved method for compressive sensing by introducing a self training dictionary scheme and a CS reconstruction method based on A*OLS, which enhances the sparse representation performance of propeller signals.
