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Theoretical and experimental study of a bi-stable piezoelectric energy harvester under hybrid galloping and band-limited random excitations

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Applied Mathematics and Mechanics(English Edition) 2024年第3期45卷 461-478页

作者： haitao LI Tianyu ZHENG Weiyang QIN Ruilan TIAN Hu DING J.C.JI Liqun chen Department of Engineering Mechanics North University of ChinaTaiyuan 030051China Department of Engineering Mechanics Northwestern Polytechnical UniversityXi'an 710072China Department of Engineering Mechanics Shijiazhuang Tiedao UniversityShijiazhuang 050043China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai Frontier Science Center of MechnoinformaticsShanghai Institute of Applied Mathematics and MechanicsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai 200072China School of Mechanical and Mechatronic Engineering University of Technology SydneyNew South Wales 2007Australia

In the practical environment,it is very common for the simultaneous occurrence of base excitation and crosswind.Scavenging the combined energy of vibration and wind with a single energy harvesting structure is fascinating.For this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy envelope.The results of the analytical prediction are verified with the Monte-Carlo method(MCM).The numerical simulation shows that the introduction of wind can reduce the critical excitation level for triggering an inter-well jump and make a bi-stable energy harvester(BEH)realize the performance enhancement for a weak base excitation.However,as the strength of the wind increases to a particular level,the influence of the random base excitation on the dynamic responses is weakened,and the system exhibits a periodic galloping response.A comparison between a BEH and a linear energy harvester(LEH)indicates that the BEH demonstrates inferior performance for high-speed wind.Relevant experiments are conducted to investigate the validity of the theoretical prediction and numerical simulation.The experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind speeds.However,as the speed of the incoming wind is up to a particular level,the disadvantage of the BEH becomes clear and evident.

关键词： bi-stability inter-well response galloping band-limited random

Gradient sparsification for efficient wireless federated learning with differential privacy

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Science China(Information Sciences) 2024年第4期67卷 272-288页

作者： Kang WEI Jun LI Chuan MA Ming DING Feng SHU haitao ZHAO Wen chen Hongbo ZHU School of Electronic and Optical Engineering Nanjing University of Science and Technology Zhejiang Lab Key Laboratory of Computer Network and Information Integration(Southeast University) Ministry of Education Data61 Commonwealth Scientific and Industrial Research Organisation School of Information and Communication Engineering Hainan University School of Communications and Information Engineering Nanjing University of Posts and Telecommunications School of Electronic Information and Electrical Engineering Shanghai Jiao Tong University

Federated learning(FL) enables distributed clients to collaboratively train a machine learning model without sharing raw data with each other. However, it suffers from the leakage of private information from uploading models. In addition, as the model size grows, the training latency increases due to the limited transmission bandwidth and model performance degradation while using differential privacy(DP)protection. In this paper, we propose a gradient sparsification empowered FL framework with DP over wireless channels, to improve training efficiency without sacrificing convergence performance. Specifically, we first design a random sparsification algorithm to retain a fraction of the gradient elements in each client’s local model, thereby mitigating the performance degradation induced by DP and reducing the number of transmission parameters over wireless channels. Then, we analyze the convergence bound of the proposed algorithm, by modeling a non-convex FL problem. Next, we formulate a time-sequential stochastic optimization problem for minimizing the developed convergence bound, under the constraints of transmit power, the average transmitting delay, as well as the client’s DP requirement. Utilizing the Lyapunov drift-plus-penalty framework, we develop an analytical solution to the optimization problem. Extensive experiments have been implemented on three real-life datasets to demonstrate the effectiveness of our proposed algorithm. We show that our proposed algorithms can fully exploit the interworking between communication and computation to outperform the baselines, i.e., random scheduling, round robin, and delay-minimization algorithms.

关键词： federated learning differential privacy gradient sparsification Lyapunov drift convergence analysis

Multi-dimensional multiplexing optical secret sharing framework with cascaded liquid crystal holograms

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Opto-Electronic Advances 2024年第1期7卷 28-35页

作者： Keyao Li Yiming Wang Dapu Pi Baoli Li haitao Luan Xinyuan Fang Peng chen Yanqing Lu Min Gu Institute of Photonic Chips University of Shanghai for Science and TechnologyShanghai 200093China Centre for Artificial-Intelligence Nanophotonics School of Optical-Electrical and Computer EngineeringUniversity of Shanghai for Science and TechnologyShanghai 200093China National Laboratory of Solid State Microstructures and College of Engineering and Applied SciencesNanjing UniversityNanjing 210093China

Secret sharing is a promising technology for information encryption by splitting the secret information into different shares.However,the traditional scheme suffers from information leakage in decryption process since the amount of available information channels is limited.Herein,we propose and demonstrate an optical secret sharing framework based on the multi-dimensional multiplexing liquid crystal(LC)holograms.The LC holograms are used as spatially separated shares to carry secret images.The polarization of the incident light and the distance between different shares are served as secret keys,which can significantly improve the information security and capacity.Besides,the decryption condition is also restricted by the applied external voltage due to the variant diffraction efficiency,which further increases the information security.In implementation,an artificial neural network(ANN)model is developed to carefully design the phase distribution of each LC hologram.With the advantage of high security,high capacity and simple configuration,our optical secret sharing framework has great potentials in optical encryption and dynamic holographic display.

关键词： holographic encryption optical secret sharing cascaded liquid crystal hologram multi-dimensional multiplexing

The application of the strip-shaped cymba conchae orthosis in the nonsurgical correction of complex auricular deformity

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Journal of Otology 2024年第1期19卷 24-29页

作者： Huijuan Xu Shaoguang Ding Fei Zhang Zhifeng Zhang Xiangyu chen Mingyang Li haitao Yang Fugen Han Hongjian Liu Department of Otolaryngology Head and Neck Surgery People’s Hospital of Henan UniversityHenan Provincial People’s HospitalZhengzhouChina Department of Otolaryngology Head and Neck Surgery Henan Provincial People’s HospitalPeople’s Hospital of Zhengzhou UniversityPeople’s Hospital of Henan UniversityZhengzhouChina Department of Otolaryngology Head and Neck Surgery Henan Children’s HospitalZhengzhouChina Department of Otolaryngology Head and Neck Surgery The Third People’s Hospital of ZhengzhouZhengzhouChina Zheng Dong Mihuan Clinic ZhengzhouChina

Objective: This study aims to evaluate the efficacy and safety of using a strip-shaped cymba conchae orthosis for the nonsurgical correction of complex auricular deformities. Methods: Clinical data were collected from 2020 to 2021 for 6 patients who underwent correction using a stripshaped cymba conchae orthosis. The indications, corrective effects, and complications associated with use of the orthosis were analyzed. Results: There were four indications for treatment: cryptotia with helix adhesion;cryptotia with grade I microtia;cryptotia with excessive helix thickness;and auricular deformity beyond the treatment time window(≥6 months). Excellent corrective effects were observed in all 6 patients. Complications occurred in one patient, who recovered after symptomatic treatment. Conclusion: The use of a strip-shaped cymba conchae orthosis alone or combined with a U-shaped helix orthosis presents a feasible approach for correcting complex auricular deformities or deformities beyond the treatment time window in pediatric patients.

关键词： Cymba conchae Auricular deformity Cryptotia Nonsurgical correction Orthosis

Observation of accurately designed bound states in the continuum in momentum space

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Photonics Research 2024年第4期12卷 638-647页

作者： JIAJU WU JINGGUANG chen XIN QI ZHIWEI GUO JIAJUN WANG FENG WU YONG SUN YUNHUI LI haitao JIANG LEI SHI JIAN ZI HONG chen MOE Key Laboratory of Advanced Micro-Structured Materials School of Physics Science and EngineeringTongji UniversityShanghai 200092China State Key Laboratory of Surface Physics Key Laboratory of Micro-and Nano-Photonic Structures(Ministry of Education)and Department of PhysicsFudan UniversityShanghai 200433China School of Optoelectronic Engineering Guangdong Polytechnic Normal UniversityGuangzhou 510665China

Bound states in the continuum(BICs)in artificial photonic structures have received considerable attention since they offer unique methods for the extreme field localization and enhancement of light-matter interactions.Usually,the symmetry-protected BICs are located at high symmetric points,while the positions of accidental BICs achieved by tuning the parameters will appear at some points in momentum space.Up to now,to accurately design the position of the accidental BIC in momentum space is still a challenge.Here,we theoretically and experimentally demonstrate an accurately designed accidental BIC in a two-coupled-oscillator system consisting of bilayer gratings,where the optical response of each grating can be described by a single resonator model.By changing the interlayer distance between the gratings to tune the propagation phase shift related to wave vectors,the position of the accidental BIC can be arbitrarily controlled in momentum space.Moreover,we present a general method and rigorous numerical analyses for extracting the polarization vector fields to observe the topological properties of BICs from the polarization-resolved transmission spectra.Finally,an application of the highly efficient second harmonic generation assisted by quasi-BIC is demonstrated.Our work provides a straightforward strategy for manipulating BICs and studying their topological properties in momentum space.

关键词： polarization tuning resonator

Sedimentary Characteristics,Ages,and Environmental Significance of Gravel Deposits and Loess in Shandong,Eastern China:Regional Response to Global Change Since the Last Glacial Period

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Acta Geologica Sinica(English Edition) 2024年第2期98卷 491-504页

作者： WANG Min KONG Fanbiao KONG Xianglun chen haitao WANG Jiawei MIAO Xiaodong JIA Guangju HAN Mei XU Shujian Department of Geography and Tourism Qilu Normal UniversityJinan 250014China School of Geography and Environment Shandong Normal UniversityJinan 250014China Shandong Provincial Key Laboratory of Water and Soil Conservation and Environmental Protection Linyi UniversitySchool of Resources and EnvironmentLinyiShandong 276005China College of Earth Science and Engineering Shandong University of Science and TechnologyQingdaoShandong 266590China

Investigation of rarely studied gravel layers found in the loess in Shandong Province,eastern China,reveals the fabric characteristics of two gravel layers(G1,G2)and the sedimentary characteristics of loess at the typical and well-preserved Heiyu section(HY),where,to determine the paleoclimatic changes during Marine Isotope Stage 3a.Optically stimulated luminescence dates of the HY formation range from 0.26±0.02 ka to 39.00±2.00 ka.In addition,the ages of G1 and G2 were estimated using the Bayesian model to be 39.60-40.50 and 29.00-29.50 ka.G1 and G2 are mainly composed of fine and medium gravel,both of which were subangular to subrounded limestone,with gravel directions to NE and E.The average flow velocity,average depth,and flood peak flow of G1 are 1.10 m/s,0.49 m,and 37.04 m^(3)/s,respectively,calculated using the flow energy method,whereas those of G2 are 0.98 m/s,0.38 m,and 18.38 m^(3)/s,respectively.Analysis of climate proxy indices show that the sedimentary environment of the gravel and loess in HY might be a regional response to global change.

关键词： paleoenvironment geochronology gravel layer sedimentology Pleistocene Shandong Province

Knockdown of HE4 suppresses tumor growth and invasiveness in lung adenocarcinoma through regulation of EGFR signaling

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Oncology Research 2024年第6期32卷 1119-1128页

作者： YUE ZHANG WENYU YANG XIAOWANG HAN YUE QIAO haitao WANG TING chen TIANYING LI WEN-BIN OU Department of Biopharmaceutics College of Life Sciences and MedicineZhejiang Provincial Key Laboratory of Silkworm Bioreactor and BiomedicineZhejiang Sci-Tech UniversityHangzhou310018China Department of Thoracic Surgery Zhejiang Provincial People’s HospitalHangzhou310014China

It has been shown that the high expression of human epididymis protein 4(HE4)in most lung cancers is related to the poor prognosis of patients,but the mechanism of pathological transformation of HE4 in lung cancer is still unclear.The current study is expected to clarify the function and mechanism of HE4 in the occurrence and metastasis of lung adenocarcinoma(LUAD).Immunoblotting evaluated HE4 expression in lung cancer cell lines and biopsies,and through analysis of The Cancer Genome Atlas(TCGA)dataset.Frequent HE4 overexpression was demonstrated in LUAD,but not in lung squamous cell carcinoma(LUSC),indicating that HE4 can serve as a biomarker to distinguish between LUAD and LUSC.HE4 knockdown significantly inhibited cell growth,colony formation,wound healing,and invasion,and blocked the G1-phase of the cell cycle in LUAD cell lines through inactivation of the EGFR signaling downstream including PI3K/AKT/mTOR and RAF/MAPK pathways.The first-line EGFR inhibitor gefitinib and HE4 shRNA had no synergistic inhibitory effect on the growth of lung adenocarcinoma cells,while the third-line EGFR inhibitor osimertinib showed additive anti-proliferative effects.Moreover,we provided evidence that HE4 regulated EGFR expression by transcription regulation and protein interaction in LUAD.Our findings suggest that HE4 positively modulates the EGFR signaling pathway to promote growth and invasiveness in LUAD and highlight that targeting HE4 could be a novel strategy for LUAD treatment.

关键词： Lung adenocarcinoma Human epididymis protein 4 Epidermal growth factor receptor Biomarker Targeted therapies

Mitigating Lattice Distortion of High‑Voltage LiCoO_(2)via Core‑Shell Structure Induced by Cationic Heterogeneous Co‑Doping for Lithium‑Ion Batteries

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Nano-Micro Letters 2024年第3期16卷 169-182页

作者： Zezhou Lin Ke Fan Tiancheng Liu Zhihang Xu Gao chen Honglei Zhang Hao Li Xuyun Guo Xi Zhang Ye Zhu Peiyu Hou haitao Huang Department of Applied Physics and Research Institute for Smart Energy The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China Department of Applied Physics The Hong Kong Polytechnic UniversityHong KongPeople’s Republic of China Institute of Nanosurface Science and Engineering Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics EngineeringShenzhen UniversityShenzhenPeople’s Republic of China School of Physics and Technology University of JinanJinanShandongPeople’s Republic of China

Inactive elemental doping is commonly used to improve the structural stability of high-voltage layered transition-metal oxide cathodes.However,the one-step co-doping strategy usually results in small grain size since the low diffusivity ions such as Ti^(4+)will be concentrated on grain boundaries,which hinders the grain growth.In order to synthesize large single-crystal layered oxide cathodes,considering the different diffusivities of different dopant ions,we propose a simple two-step multi-element co-doping strategy to fabricate core–shell structured LiCoO_(2)(CS-LCO).In the current work,the high-diffusivity Al^(3+)/Mg^(2+)ions occupy the core of single-crystal grain while the low diffusivity Ti^(4+)ions enrich the shell layer.The Ti^(4+)-enriched shell layer(~12 nm)with Co/Ti substitution and stronger Ti–O bond gives rise to less oxygen ligand holes.In-situ XRD demonstrates the constrained contraction of c-axis lattice parameter and mitigated structural distortion.Under a high upper cut-off voltage of 4.6 V,the single-crystal CS-LCO maintains a reversible capacity of 159.8 mAh g^(−1)with a good retention of~89%after 300 cycles,and reaches a high specific capacity of 163.8 mAh g^(−1)at 5C.The proposed strategy can be extended to other pairs of low-(Zr^(4+),Ta^(5+),and W6+,etc.)and high-diffusivity cations(Zn^(2+),Ni^(2+),and Fe^(3+),etc.)for rational design of advanced layered oxide core–shell structured cathodes for lithium-ion batteries.

关键词： Lithium-ion battery LiCoO_(2) Heterogeneous co-doping Core-shell structure High-voltage stability

Level pinning of anti-PT-symmetric circuits for efficient wireless power transfer

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National Science Review 2024年第1期11卷 215-224页

作者： Zhiwei Guo Fengqing Yang Haiyan Zhang Xian Wu Qiong Wu Kejia Zhu Jun Jiang haitao Jiang Yaping Yang Yunhui Li Hong chen MOE Key Laboratory of Advanced Micro-Structured Materials School of Physics Sciences and Engineering Tongji University Department of Electrical Engineering Tongji University School of Automotive Studies Tongji University

Wireless power transfer(WPT) technology based on magnetic resonance(a basic physical phenomenon)can directly transfer energy from the source to the load without wires and other physical contacts, and has been successfully applied to implantable medical devices, electric vehicles, robotic arms and other fields.However, due to the frequency splitting of near-field coupling, the resonant WPT system has some unique limitations, such as poor transmission stability and low efficiency. Here, we propose anti-resonance with level pinning for high-performance WPT. By introducing the anti-resonance mode into the basic WPT platform, we uncover the competition between dissipative coupling and coherent coupling to achieve novel level pinning, and construct an effective anti-parity-time(anti-PT)-symmetric non-Hermitian system that is superior to previous PT-symmetric WPT schemes. On the one hand, the eigenvalue of the anti-PT-symmetric system at resonance frequency is always pure real in both strong and weak coupling regions, and can be used to overcome the transmission efficiency decrease caused by weak coupling, as brought about by, for example, a large size ratio of the transmitter to receiver, or a long transmission distance.On the other hand, due to the level pinning effect of the two kinds of coupling mechanisms, the working frequency of the system is guaranteed to be locked, so frequency tracking is not required when the position and size of the receiver change. Even if the system deviates from the matching condition, an efficient WPT can be realized, thereby demonstrating the robustness of the level pinning. The experimental results show that when the size ratio of the transmitter coil to the receiver coil is 4.29(which is in the weak coupling region), the transfer efficiency of the anti-PT-symmetric system is nearly 4.3(3.2) times higher than that of the PT-symmetric system when the matching conditions are satisfied(deviated). With the miniaturization and integration of devices in mind, a synthetic anti-PT-symmetric sy

关键词： non-Hermitian system wireless power transfer anti-PT-symmetric circuits synthetic dimension metamaterials