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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 *** the combined energy of vibration and wind with a single energy harvesting structure is *** this purpose,the effects of the wind speed and random excitation level are investigated with the stochastic averaging method(SAM)based on the energy *** 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 ***,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 *** experiments are conducted to investigate the validity of the theoretical prediction and numerical *** experimental findings also show that strong random excitation is favorable for the BEH in the range of low wind ***,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

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Current and future perspectives on the regulation and functions of miR-545 in cancer development

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Cancer Pathogenesis and Therapy 2024年第3期2卷 142-154页

作者： Jinze Shen Xinming Su Qurui Wang Yufei Ke tianyu zheng Yunan Mao Zehua Wang Jingyin Dong Shiwei Duan Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province School of MedicineHangzhou City UniversityHangzhouZhejiang 310015China

Micro ribonucleic acids(miRNAs)are a highly conserved class of single-stranded non-coding *** the miR-545/374a cluster,miR-545 resides in the intron of the long non-coding RNA(lncRNA)FTX on *** precursor form,pre-miR-545,is cleaved to generate two mature miRNAs,miR-545-3p and ***,these two miRNAs exhibit distinct aberrant expression patterns in different cancers;however,their expression in colorectal cancer remains ***,miR-545-3p is affected by 15 circular RNAs(circRNAs)and 10 long non-coding RNAs(lncRNAs),and it targets 27 protein-coding genes(PCGs)that participate in the regulation of four signaling *** contrast,miR-545-5p is regulated by one circRNA and five lncRNAs,it targets six PCGs and contributes to the regulation of one signaling *** miR-545-3p and miR-545-5p affect crucial cellular behaviors,including cell cycle,proliferation,apoptosis,epithelial-mesenchymal transition,invasion,and *** low miR-545-3p expression is associated with poor prognosis in three cancer types,studies on miR-545-5p are yet to be ***-545-3p operates within a diverse range of regulatory networks,thereby augmenting the efficacy of cancer chemotherapy,radiotherapy,and ***,miR-545-5p enhances immunotherapy efficacy by inhibiting T-cell immunoglobulin and mucin-domain containing-3(TIM-3)*** summary,miR-545 holds immense potential as a cancer biomarker and therapeutic *** aberrant expression and regulatory mechanisms of miR-545 in cancer warrant further investigation.

关键词： miR-545 Competing endogenous RNA Cell behavior Biomarker Therapeutic drug Immunotherapy

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结合生成对抗网络的电阻抗断层成像技术在肺通气监测中的应用

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生物医学工程学杂志 2024年第1期41卷 105-113页

作者：赵明康刘珺郭忠圣陈祥琪张帅郑天予河北工业大学生命科学与健康工程学院天津300130 河北工业大学省部共建电工装备可靠性与智能化国家重点实验室天津300130 天津市生物电工与智能健康重点实验室天津300130

电阻抗断层成像(EIT)技术在肺通气监测和区域性肺功能检测中发挥着重要作用。然而,EIT算法固有的病态特性导致从含有噪声的电压数据中求解电导率时存在明显偏差,难以获得准确的电导率变化分布图像以及清晰的边界轮廓。为了提高EIT在肺... 详细信息

电阻抗断层成像(EIT)技术在肺通气监测和区域性肺功能检测中发挥着重要作用。然而,EIT算法固有的病态特性导致从含有噪声的电压数据中求解电导率时存在明显偏差,难以获得准确的电导率变化分布图像以及清晰的边界轮廓。为了提高EIT在肺通气监测中的成像质量,本文提出将EIT算法与深度学习算法相结合的方法。首先,引用优化因子对卡尔曼滤波算法进行修正并将吉洪诺夫(Tikhonov)正则化引入算法的状态空间表达式,以获得初始肺部重建图像;其次将初始成像结果输入生成对抗网络模型,以重构出精确的肺部轮廓。仿真实验结果表明,该方法生成的肺部图像边界清晰,对噪声具有更强的鲁棒性,基本实现了可视化的效果,可为计算机断层扫描等影像的诊断提供参考意义。

关键词：电阻抗断层成像卡尔曼滤波生成对抗网络图像重建

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A new approach for inversion of receiver function for crustal structure in the depth domain

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Earth and Planetary Physics 2022年第1期6卷 83-95页

作者： tianyu zheng YuMei He Yue Zhu Key Laboratory of Earth and Planetary Physics Institute of Geology and GeophysicsChinese Academy of Sciences(CAS)Beijing 100029China University of Chinese Academy of Sciences Beijing 100049China

A method for reconstructing crustal velocity structure using the optimization of stacking receiver function amplitude in the depth domain,named common conversion amplitude(CCA)inversion,is *** conversion amplitude in the depth domain,which represents the impedance change in the medium,is obtained by assigning the receiver function amplitude to the corresponding conversion position where the P-to-S conversion *** the conversion amplitude variation with depth as an optimization objective,imposing reliable prior constraints on the structural model frame and velocity range,and adopting a stepwise search inversion technique,this method efficiently weakens the tendency of easily falling into the local extremum in conventional receiver function *** tests show that the CCA inversion can reconstruct complex crustal velocity structures well and is especially suitable for revealing crustal evolution by estimating diverse velocity *** performance in reconstructing crustal structure is superior to that of the conventional receiver function imaging method.

关键词： crustal imaging receiver function depth domain inversion

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Mantle dynamics of the reactivating North China Craton:Constraints from the topographies of the 410-km and 660-km discontinuities

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Science China Earth Sciences 2011年第6期54卷 881-887页

作者： XU WeiWei zheng tianyu ZHAO Liang Seismological Laboratory State Key Laboratory of Lithospheric Evolution Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

The topographies of the 410-km and 660-km discontinuities have important implications for mantle *** we present high-resolution seismic imaging of the 410-km and 660-km discontinuities beneath the North China Craton (NCC) employing the receiver function *** anomalies (deeper or shallower than the global average depths) at both discontinuities were detected by introducing a three-dimensional regional velocity *** depressions of the 410-km discontinuity are mostly located in the eastern NCC.A local elevation of the 660-km discontinuity appeared in the northwest of the NCC and a significant depression of the 660-km discontinuity is located in the southeast of the *** dynamic mantle regimes are speculated to explain the formation of the anomalous depth zones in the *** possibility is a complex mantle upwelling linked to edge-derived convection between the stagnant slab and the thick cratonic *** other potential dynamic regime is slab stagnating,sinking,and induced upwelling at the neighboring slab *** regimes hint that the mantle flow was possibly dominated by dynamic interactions among the subducting slab,cratonic root,and ambient mantle beneath the NCC.

关键词： 410-km discontinuity 660-km discontinuity receiver function imaging dynamic mantle regime North China Craton

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Destruction geodynamics of the North China Craton and its Paleoproterozoic plate tectonics

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Chinese Science Bulletin 2009年第19期54卷 3354-3366页

作者： ZHU RiXiang zheng tianyu Paleomagnetism and Geochronology Laboratory (SKL-LE) Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 China

Much attention has been paid in the last two decades to the physical and chemical processes as well as temporal-spatial variations of the lithospheric mantle beneath the North China Craton. In order to provide insights into the geodynamics of this variation, it is necessary to thoroughly study the state and structure of the lithospheric crust and mantle of the North China Craton and its adjacent regions as an integrated unit. Based on the velocity structure of the crust and upper mantle constrained from seismological studies, this paper presents various available geophysical results regarding the lithosphere thickness, the nature of crust-mantle boundary, the upper mantle structure and deformation characteristics as well as their tectonic features and evolution systematics. Combined with the obtained data from petrology and geochemistry, a mantle flow model is proposed for the tectonic evolution of the North China Craton during the Mesozoic-Cenozoic. We suggest that subduction of the Pacific plate made the mantle underneath the eastern Asian continent unstable and able to flow faster. Such a regional mantle flow system would cause an elevation of melt/fluid content in the upper mantle of the North China Craton and the lithospheric softening, which, subsequently resulted in destruction of the North China Craton in different ways of delamination and thermal erosion in Yanshan, Taihang Mountains and the Tan-Lu Fault zone. Multiple lines of evidence recorded in the crust of the North China Craton, such as the amalgamation of the Archean eastern and western blocks, the subduction of Paleo-oceanic crust and Paleo-continental residue, indicate that the Earth in the Paleoproterozoic had already evolved into the plate tectonic system similar to the present plate tectonics.

关键词：地球动力学筑造学研究调查

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Integrated guidance and control design of a flight vehicle with side-window detection

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Chinese Journal of Aeronautics 2018年第4期31卷 749-764页

作者： tianyu zheng Yu YAO Fenghua HE Denggao JI Department of Astronautics Harbin Institute of Technology Harbin 150080 China Beijing Institute of Nearspace Vehicle's Systems Engineering Beijing 100083 China

This paper considers the guidance and control problem of a flight vehicle with sidewindow detection. In order to guarantee the target remaining in the seeker＇s sight of view, the line of sight and the attitude of the flight vehicle should be under some constraints caused by the sidewindow, which leads to coupling between the guidance and the attitude dynamics model. To deal with the side-window constraints and the coupling, a novel Integrated Guidance and Control（IGC）design approach is proposed. Firstly, the relative motion equations are derived in the body-Line of Sight（LOS） coordinate system. And the guidance and control problem of the flight vehicle is formulated into an IGC problem with state constraints. Then, based on the singular perturbation method, the IGC problem is decomposed into the control design of the quasi-steady-state subsystem and the boundary-layer subsystem which can be designed separately. Finally, the receding horizon control is applied to the control design for the two subsystems. Simulation results show the effectiveness of the proposed approach.

关键词： Integrated guidance and control Receding horizon control Side-window detection Singular perturbation Terminal guidance

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Active switching multiple model method for tracking a noncooperative gliding flight vehicle

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Science China(Information Sciences) 2020年第9期63卷 156-174页

作者： tianyu zheng Yu YAO Fenghua HE Denggao JI Xinran ZHANG School of Astronautics Harbin Institute of Technology Beijing Institute of Nearspace Vehicle's Systems Engineering

The study investigates the trajectory estimation problem of a noncooperative gliding flight vehicle with complex and atypical maneuvers. An active switching multiple model(ASMM) method is *** method employs a motion behavior model set(MBMS), a motion behavior recognition algorithm, and an active switching estimation and fusion algorithm. First, a recognizable MBMS, which can capture all the motion behaviors of a gliding flight vehicle, is established. Then, a motion behavior recognition algorithm based on recurrent neural networks(RNNs) is developed to obtain the current probability of each motion behavior. Then, an active switching estimation and fusion algorithm is proposed, in which the adopted models are actively chosen at each time instant according to a model selection strategy. Last, the proposed ASMM method is applied to a noncooperative gliding flight vehicle. The simulation results show that the proposed method has higher estimation precision and better dynamic performance.

关键词： gliding flight vehicle target tracking multiple model estimation and fusion motion behavior recurrent neural networks

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Determining the key conditions for the formation of metamorphic core complexes by geodynamic modeling and insights into the destruction of North China Craton

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Science China Earth Sciences 2016年第9期59卷 1873-1884页

作者： LU Gang ZHAO Liang zheng tianyu WANG Kun YANG JianFeng State Key Laboratory of Lithospheric Evolution of Geology and Geophysics Chinese Academy of Sciences

Metamorphic core complex(MCC) is characterized by the exhumation of lower crust over a large-scale detachment fault, providing natural records for tectonic extension. MCCs are widely identified in the North China Craton(NCC), which have been intensively studied on their structural and geological characteristics. Yet, the condition for the formation of MCCs and their link with NCC destruction are still in debate. In this study, we perform numerical simulations to investigate MCC formation under extension, with a focus on the effect of crustal rheologies. Results indicate that three end-member modes of deformation may occur: the metamorphic core complex mode, the detachment fault-uplifting mode and the pure shear mode. Weaker lower crust and stronger upper crust may promote the formation of MCC. In contrast, stronger lower crust(>1.3×1021 Pa s) may prohibit the exhumation of lower crust(detachment fault-uplifting mode), while weaker upper crust(<7.8×1021 Pa s) may fail to develop detachment faults(pure shear mode). Given that cratons typically have a strong crust, we suggest that the lower crust of NCC was weakened prior to extension, which promoted the formation of MCC in a later stage under the back-arc extension.

关键词： Metamorphic core complex Numerical modeling North China Craton Extension

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基于改进高斯拟合的红外相机视角下标识点中心定位方法

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激光杂志 2024年第4期45卷 59-64页

作者：鲍勃屹张辉朱成顺郑天宇张震江苏科技大学机械工程学院江苏镇江212003

针对红外相机视角下标识点中心提取问题,在分析其图像特征的基础上,提出一种粗细结合的分割及高斯拟合的方法以实现对标识点中心的定位。首先根据图像中标识点的灰度差异,对其进行ROI粗定位,去除背景反光对其分割的影响。随后对目标图... 详细信息

针对红外相机视角下标识点中心提取问题,在分析其图像特征的基础上,提出一种粗细结合的分割及高斯拟合的方法以实现对标识点中心的定位。首先根据图像中标识点的灰度差异,对其进行ROI粗定位,去除背景反光对其分割的影响。随后对目标图像采用K均值聚类算法,实现目标分割。最后,通过剔除中心冗余信息的改进高斯拟合提取方法,得到标识点光斑中心坐标。实验结果表明,相较于灰度质心法、Hough变换法和圆拟合法,本方法对其中心提取稳定性误差均小于0.1像素,具有高重复性和稳定性精度。即使目标产生不同程度遮挡时仍具有较高精度,适合于红外相机视角下定位系统的标识点中心提取。

关键词：光斑检测图像分割中心提取光学测量

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