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振动调频信号的循环平稳解调原理与实现方法

振动与冲击 2006年第1期25卷 5-9页

作者：丁康孔正国李巍华华南理工大学汽车工程学院广州510640 汕头大学机械电子工程系汕头515063

含有齿轮、滚动轴承等零部件的机械故障振动信号中,有一类信号称为频率调制信号(或称调相信号)。运用循环平稳分析理论,推导调频信号的循环自相关函数结果,并从理论上推导和分析了运用平方解调(或广义检波滤波解调)的方法实现对循环自... 详细信息

含有齿轮、滚动轴承等零部件的机械故障振动信号中,有一类信号称为频率调制信号(或称调相信号)。运用循环平稳分析理论,推导调频信号的循环自相关函数结果,并从理论上推导和分析了运用平方解调(或广义检波滤波解调)的方法实现对循环自相关函数的低频切片函数和高频切片函数进行解调的原理和方法,仿真验证理论推导正确,解调效果很好。最后通过对齿轮箱实测故障信号进行分析,验证该方法有很好的解调效果。

关键词：调频信号循环平稳分析切片函数解调故障诊断

Improving Transferable Targeted Adversarial Attack for Object Detection Using RCEN Framework and Logit Loss Optimization

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Computers, Materials & Continua 2024年第9期80卷 4387-4412页

作者： Zhiyi ding Lei Sun Xiuqing Mao Leyu Dai Ruiyang ding School of Cryptography Engineering Information Engineering UniversityZhengzhou450000China

Object detection finds wide application in various sectors,including autonomous driving,industry,and *** studies have highlighted the vulnerability of object detection models built using deep neural networks when confronted with carefully crafted adversarial *** not only reveals their shortcomings in defending against malicious attacks but also raises widespread concerns about the security of existing *** existing adversarial attack strategies focus primarily on image classification problems,failing to fully exploit the unique characteristics of object detectionmodels,thus resulting in widespread deficiencies in their ***,previous research has predominantly concentrated on the transferability issues of non-targeted attacks,whereas enhancing the transferability of targeted adversarial examples presents even greater *** attack techniques typically employ cross-entropy as a loss measure,iteratively adjusting adversarial examples to match target ***,their inherent limitations restrict their broad applicability and transferability across different *** address the aforementioned challenges,this study proposes a novel targeted adversarial attack method aimed at enhancing the transferability of adversarial samples across object detection *** the framework of iterative attacks,we devise a new objective function designed to mitigate consistency issues arising from cumulative noise and to enhance the separation between target and non-target categories(logit margin).Secondly,a data augmentation framework incorporating random erasing and color transformations is introduced into targeted adversarial *** enhances the diversity of gradients,preventing overfitting to white-box ***,perturbations are applied only within the specified object’s bounding box to reduce the perturbation range,enhancing attack *** were conducted on the Microsoft

关键词： Object detection model security targeted attack gradient diversity

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振动调幅信号的循环平稳解调原理与应用

振动工程学报 2005年第3期18卷 304-308页

作者：丁康孔正国何志达西安交通大学机械工程学院汕头大学机械电子工程系广东汕头515063

在具有齿轮、滚动轴承的机械设备故障诊断中,广泛使用解调分析方法进行故障特征提取。对其中的周期平稳信号,通过循环自相关函数分析,并利用函数在某些循环频率下的切片进行绝对值解调可解出信号的调制频率。对两组调制相加信号在对应... 详细信息

在具有齿轮、滚动轴承的机械设备故障诊断中,广泛使用解调分析方法进行故障特征提取。对其中的周期平稳信号,通过循环自相关函数分析,并利用函数在某些循环频率下的切片进行绝对值解调可解出信号的调制频率。对两组调制相加信号在对应于某个调制频率的循环频率处进行循环自相关函数的切片解调,可得到该组调制频率成分的解调谱,从而达到将幅值调制相加信号分离成单一幅值调制信号并进行有效解调的目的。仿真和对滚动轴承实验验证,该方法在低频和高频处分别切片都有很好的解调效果,且与理论推导一致。但是该方法存在解两相加信号时以两频率之差及其倍频作为调制频率解出的局限性。

关键词：解调循环平稳绝对值分析故障诊断

Identification of an Underside Binding Site in Smoothened Receptor

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Identification of an Underside Binding Site in Smoothened Re...

A viscoelastic metamaterial beam for integrated vibration isolation and energy harvesting

第十一届全国化学生物学学术会议

作者： Fang Zhou kang ding Yiqing Zhou Yang Liu Youli Xiao Suwen Zhao Houchao Tao iHuman Institute ShanghaiTech University CAS Key Laboratory of Synthetic Biology Institute of Plant Physiology and EcologyShanghai Institutes for Biological SciencesChinese Academy of Sciences

An underside binding site was identified in the transmembrane domain of smoothened receptor(SMO) by a colocalization *** structurally complementary photoaffinity probes were designed by appending azide group at two ends of a known ligand *** on the comprehensive analysis of digestive MS data,the binding was determined which was further corroborated by docking and simulation *** key interactions include two pairs of hydrogen bonds,a stable cage involving several π-π interactions,and hydrophobic interaction between Allo-1 and its contacting *** results reveal the molecular base of Allo-1 binding and more importantly,the possible mechanism for its anti-drug resistance activity.

关键词： Smoothened receptor colocalization strategy binding site drug resistance

来源： cnki会议评论

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Applied Mathematics and Mechanics(English Edition) 2024年第7期45卷 1243-1260页

作者： Long ZHAO Zeqi LU Hu ding Liqun CHEN Shanghai Institute of Applied Mathematics and Mechanics Shanghai Key Laboratory of Mechanics in Energy EngineeringShanghai Frontier Science Center of MechanoinformaticsSchool of Mechanics and Engineering ScienceShanghai UniversityShanghai200072China School of Microelectronics Shanghai UniversityShanghai201800China

Locally resonant metamaterials have low-frequency band gaps and the capability of converging vibratory energy in the band gaps at resonant *** has been demonstrated by several researchers that the dissipatioin of vibratory energy within the band gap can be improved by using viscoelastic *** paper designs an integrated viscoelastic metamaterial for energy harvesting and vibration *** viscoelastic metamaterial is achieved by a viscoelastic beam periodically arrayed with spatial ball-pendulum nonlinear energy *** nonlinear resonator with an energy harvesting function is achieved by placing a free-rolling magnetic ball in a spherical cavity with an additional induction *** dynamic equations of viscoelastic metamaterials under transverse excitation are established,and the energy harvesting and vibration isolation characteristics within the dispersion relation of viscoelastic metamaterials are *** results show that the vibrations of the main body of the viscoelastic metamaterial beam are significantly suppressed in the frequency range of the local resonance band *** the same time,the elastic waves are limited in the nonlinear resonator with an energy harvesting function,which improves the energy ***,an experimental platform of viscoelastic metamaterial vibration is established for validation purposes.

关键词： viscoelastic metamaterial nonlinear vibration vibration isolation energy harvesting

Effect of hot isostatic pressure on the microstructure and tensile properties of γ'-strengthened superalloy fabricated through induction-assisted directed energy deposition

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 1089-1097页

作者： Jianjun Xu Hanlin ding Xin Lin Feng Liu Analytical&Testing Center Northwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solidification Processing Northwestern Polytechnical UniversityXi’an 710072China

The microstructure characteristics and strengthening mechanism of Inconel738LC(IN-738LC) alloy prepared by using induction-assisted directed energy deposition(IDED) were elucidated through the investigation of samples subjected to IDED under 1050℃ preheating with and without hot isostatic pressing(HIP,1190℃,105 MPa,and 3 h).Results show that the as-deposited sample mainly consisted of epitaxial columnar crystals and inhomogeneously distributed γ’ phases in interdendritic and dendritic core *** HIP,grain morphology changed negligibly,whereas the size of the γ’ phase became increasingly *** further heat treatment(HT,1070℃,2 h + 845℃,24 h),the γ’ phase in the as-deposited and HIPed samples presented a bimodal size distribution,whereas that in the as-deposited sample showed a size that remained *** comparison of tensile properties revealed that the tensile strength and uniform elongation of the HIP + HTed sample increased by 5% and 46%,respectively,due to the synergistic deformation of bimodal γ’phases,especially large cubic γ’ ***,the relationship between phase transformations and plastic deformations in the IDEDed sample was discussed on the basis of generalized stability theory in terms of the trade-off between thermodynamics and kinetics.

关键词： directed energy deposition Ni-based superalloys high-temperature preheating hot isostatic pressing microstructure tensile properties

Effective removal of Sb(V)from aqueous solutions by micro-electrolysis with composite scrap iron-manganese as filler

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第6期25卷 516-524页

作者： Shangkun ding Saihua HUANG Yiping ZHANG Yongchao ZHOU Institute of Municipal Engineering Zhejiang UniversityHangzhou310058China Zhejiang University of Water Resources and Electric Power Hangzhou310018China

Micro-electrolysis(ME)technology is investigated for improving the efficiency of removal of pentavalent antimony(Sb(V))from the *** this study,an ME system composed of scrap iron filings,waste manganese fillings,and activated carbon(Fe-Mn-C ME)was used to efficiently remove Sb(V).The results proved that,compared with conventional iron-carbon micro-electrolysis(Fe-C ME),Fe-Mn-C ME significantly enhances the removal rate of Sb(V)when the hydraulic retention time is 10–24 *** Fe-Mn flocs produced by this system were analyzed using X-ray diffraction(XRD),energy-dispersive X-ray spectroscopy(EDS),X-ray photoelectron spectroscopy(XPS),and Brunauer-Emmett-Teller(BET)surface area analysis,which revealed that the flocs were mostly Mn-substituted FeOOH and had a relatively larger specific surface area,providing better adsorption ***,it was found that the removal rate of Sb(V)decreased as the iron-carbon mass ratio increased,while it first increased and then decreased as the manganese content *** reduction of Fe(III)was accelerated with an increase in the addition of manganese,leading to an increase in the concentration of Fe(II).The electron transfer and the formation of Fe(II)were facilitated by the potential difference between manganese and carbon,as well as by the formation of microcells between iron and manganese,which improved the reduction ability of Sb(V).From our thorough investigation and research,this is the first report that has proposed Fe-Mn-C ME for removing *** provides a novel approach and technological support for removing Sb(V)efficiently.

关键词： Antimony Iron Manganese Micro-electrolysis(ME) Electrochemistry Mechanism

A multiscale differential-algebraic neural network-based method for learning dynamical systems

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International Journal of Mechanical System Dynamics 2024年第1期4卷 77-87页

作者： Yin Huang Jieyu ding College of Computer Science&Technology Qingdao UniversityQingdaoChina School of Mathematics and Statistics Qingdao UniversityQingdaoChina Center for Computational Mechanics and Engineering Simulation Qingdao UniversityQingdaoChina

The objective of dynamical system learning tasks is to forecast the future behavior of a system by leveraging observed ***,such systems can sometimes exhibit rigidity due to significant variations in component parameters or the presence of slow and fast variables,leading to challenges in *** overcome this limitation,we propose a multiscale differential-algebraic neural network(MDANN)method that utilizes Lagrangian mechanics and incorporates multiscale information for dynamical system *** MDANN method consists of two main components:the Lagrangian mechanics module and the multiscale *** Lagrangian mechanics module embeds the system in Cartesian coordinates,adopts a differential-algebraic equation format,and uses Lagrange multipliers to impose constraints explicitly,simplifying the learning *** multiscale module converts high-frequency components into low-frequency components using radial scaling to learn subprocesses with large differences in *** results demonstrate that the proposed MDANN method effectively improves the learning of dynamical systems under rigid conditions.

关键词： dynamical systems learning multibody system dynamics differential-algebraic equation neural networks multiscale structures

Analytical Expression for the Atomic Friction of a Single Asperity Based on the Prandtl-Tomlinson Model

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Acta Mechanica Solida Sinica 2024年第3期37卷 416-422页

作者： Weike Yuan Yue ding Gangfeng Wang Xinrui Niu Department of Engineering Mechanics SVLMMLXi’an Jiaotong UniversityXi’an710049China Department of Mechanical Engineering City University of Hong KongHong Kong SAR999077China

The Prandtl-Tomlinson(PT)model has been widely applied to interpret the atomic friction mechanism of a single *** this study,we present an approximate explicit expression for the friction force in the one-dimensional PT model under quasi-static ***‘stick-slip’friction curves are first approximated properly by sawtooth-like lines,where the critical points before and after the‘slip’motion are described analytically in terms of a dimensionless parameterη.Following this,the average friction force is expressed in a closed form that remains continuous and valid forη>***,an analytical expression for the load dependence of atomic friction of a single asperity is derived by connecting the parameterηwith the normal *** the parameters reported in experiments,our prediction shows good agreement with relevant experimental results.

关键词： Atomic friction Stick-slip friction Prandtl-Tomlinson model Friction force microscope