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Parametric identification of time-varying systems from free vibration using intrinsic chirp component decomposition

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Acta Mechanica Sinica 2020年第1期36卷 188-205页

作者： Sha Wei shiqian chen Xingjian Dong Zhike Peng Wenming Zhang School of Mechanics and Engineering Science Shanghai UniversityShanghai200072China Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai200072China Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai UniversityShanghai200072China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai200240China

Time-varying systems are applied extensively in practical applications,and their related parameter identification techniques are of great significance for structural health monitoring of time-varying *** improve the identification accuracy for time-varying systems,this study puts forward a novel parameter identification approach in the time-frequency domain using intrinsic chirp component decomposition(ICCD).ICCD is a powerful tool for signal decomposition and parameter extraction,with good signal reconstruction capability in a high-noise *** maintain good identification effects for the time-varying system in a noisy environment,the proposed method introduces a redundant Fourier model for the non-stationary signal,including instantaneous frequency(IF)and instantaneous amplitude(IA).The accuracy and effectiveness of the proposed approach are demonstrated by a single-degree-of-freedom system with three types of time-varying parameters,as well as an example of a multi-degree-of-freedom *** effects of different levels of measured noise on the identified results are also discussed in *** results show that the proposed method is very effective in tracking the smooth,periodical,and non-smooth variations of time-varying systems over the entire identification time period even when the response signal is contaminated by intense noise.

关键词： System identification Time-varying system Time-frequency domain Intrinsic chirp component decomposition

Modal identification of multi-degree-of-freedom structures based on intrinsic chirp component decomposition method

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Applied Mathematics and Mechanics(English Edition) 2019年第12期40卷 1741-1758页

作者： Sha WEI shiqian chen Zhike PENG Xingjian DONG Wenming ZHANG State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University

Modal parameter identification is a mature ***,there are some challenges in its practical applications such as the identification of vibration systems involving closely spaced modes and intensive noise *** paper proposes a new time-frequency method based on intrinsic chirp component decomposition(ICCD)to address these *** this method,a redundant Fourier model is used to ameliorate border distortions and improve the accuracy of signal *** effectiveness and accuracy of the proposed method are illustrated using three examples:a cantilever beam structure with intensive noise contamination or environmental interference,a four-degree-of-freedom structure with two closely spaced modes,and an impact test on a cantilever rectangular *** comparison with the identification method based on the empirical wavelet transform(EWT),it is shown that the presented method is effective,even in a high-noise environment,and the dynamic characteristics of closely spaced modes are accurately determined.

关键词： modal identification closely spaced mode time-frequency domain intrinsic chirp component decomposition(ICCD) multi-degree-of-freedom(MDOF) system

尼妥珠单抗联合诱导化疗在局晚期头颈部鳞癌中的疗效及安全性分析

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中华放射医学与防护杂志 2024年第9期44卷 741-748页

作者：雷宏彬马瑞兰陈诗倩滕云潘子萍张海琛大连医科大学附属第二医院肿瘤放疗科大连116027 大连医科大学附属第二医院胸部肿瘤科大连116027

目的探讨尼妥珠单抗联合白蛋白结合型紫杉醇+顺铂(TP)方案诱导化疗在局晚期头颈部鳞癌(LA-HNSCC)患者中的疗效及不良反应。方法回顾性收集2018年1月至2022年6月大连医科大学附属第二医院收治的65例局晚期(Ⅲ/ⅣA/ⅣB期)头颈部鳞癌(除外... 详细信息

目的探讨尼妥珠单抗联合白蛋白结合型紫杉醇+顺铂(TP)方案诱导化疗在局晚期头颈部鳞癌(LA-HNSCC)患者中的疗效及不良反应。方法回顾性收集2018年1月至2022年6月大连医科大学附属第二医院收治的65例局晚期(Ⅲ/ⅣA/ⅣB期)头颈部鳞癌(除外鼻咽癌)患者的临床信息,所有患者接受了2~3个周期的诱导治疗(IC),序贯同步放化疗(CRT)。根据诱导治疗方案分为尼妥珠单抗联合TP(Nimo-TP)组34例和TP组31例。比较两组间的近期疗效(客观缓解率)、生存结果(总生存、无进展生存、无局部区域复发生存、无远处转移生存)以及不良反应,并对影响生存结果的因素进行分析。结果Nimo-TP组和TP组1、2年无远处转移生存率差异具有统计学意义(90.4%vs.69.5%,90.4%vs.66.0%,χ^(2)=1.81,P0.05)。多因素分析显示,Nimo-TP方案诱导治疗是无远处转移生存的独立预后因素(HR=0.27,95%CI:0.07~0.97,P=0.045);诱导治疗后达到完全或部分缓解是无进展生存和无局部区域复发生存的独立预后因素(HR=0.36,95%CI:0.17~0.76,P=0.008;HR=0.28,95%CI:0.11~0.69,P=0.006)。尼妥珠单抗的加入未加重患者在诱导治疗和CRT期间的不良反应(P>0.05)。结论尼妥珠单抗联合TP方案诱导化疗序贯同步放化疗显著提高了局晚期头颈部鳞癌患者的无远处转移生存率,且安全性高,但在总生存率、无进展生存率、无局部区域复发生存率方面提高不明显,仍需进一步的研究来证实。

关键词：尼妥珠单抗表皮生长因子受体头颈部鳞癌诱导化疗同步放化疗

Non-stationary signal analysis based on general parameterized time-frequency transform and its application in the feature extraction of a rotary machine

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Frontiers of Mechanical Engineering 2018年第2期13卷 292-300页

作者： Peng ZHOU Zhike PENG shiqian chen Yang YANG Wenming ZHANG School of Mechanical Engineering Shanghai Jiao Tong University Shanghai 201100 China

With the development of large rotary machines for faster and more integrated performance, the condition monitoring and fault diagnosis for them are becoming more challenging. Since the time-frequency （TF） pattem of the vibration signal from the rotary machine often contains condition information and fault feature, the methods based on TF analysis have been widely-used to solve these two problems in the industrial community. This article introduces an effective non-stationary signal analysis method based on the general parameterized tim^fre- quency transform （GPTFT）. The GPTFT is achieved by inserting a rotation operator and a shift operator in the short-time Fourier transform. This method can produce a high-concentrated TF pattern with a general kemel. A multi-component instantaneous frequency （IF） extraction method is proposed based on it. The estimation for the IF of every component is accomplished by defining a spectrum concentration index （SCI）. Moreover, such an IF estimation process is iteratively operated until all the components are extracted. The tests on three simulation examples and a real vibration signal demonstrate the effectiveness and superiority of our method.

关键词： rotary machines condition monitoring fault diagnosis GPTFT SCI

Quantitative detection of locomotive wheel polygonization under non-stationary conditions by adaptive chirp mode decomposition

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Railway Engineering Science 2022年第2期30卷 129-147页

作者： shiqian chen Kaiyun Wang Ziwei Zhou Yunfan Yang Zaigang chen Wanming Zhai Train and Track Research Institute State Key Laboratory of Traction PowerSouthwest Jiaotong UniversityChengdu 610031China

Wheel polygonal wear is a common and severe defect,which seriously threatens the running safety and reliability of a railway vehicle especially a *** to non-stationary running conditions(e.g.,traction and braking)of the locomotive,the passing frequencies of a polygonal wheel will exhibit time-varying behaviors,which makes it too difficult to effectively detect the wheel ***,most existing methods only achieve qualitative fault diagnosis and they cannot accurately identify defect *** address these issues,this paper reports a novel quantitative method for fault detection of wheel polygonization under non-stationary conditions based on a recently proposed adaptive chirp mode decomposition(ACMD)***,a coarse-to-fine method based on the time–frequency ridge detection and ACMD is developed to accurately estimate a time-varying gear meshing frequency and thus obtain a wheel rotating frequency from a vibration acceleration signal of a *** the rotating frequency is obtained,signal resampling and order analysis techniques are applied to an acceleration signal of an axle box to identify harmonic orders related to polygonal ***,the ACMD is combined with an inertial algorithm to estimate polygonal wear *** only a dynamics simulation but a field test was carried out to show that the proposed method can effectively detect both harmonic orders and their amplitudes of the wheel polygonization under non-stationary conditions.

关键词： Wheel polygonal wear Fault diagnosis Nonstationary condition Adaptive mode decomposition Time–frequency analysis

信号分解及其在机械故障诊断中的应用研究综述

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机械工程学报 2020年第17期56卷 91-107页

作者：陈是扦彭志科周鹏西南交通大学牵引动力国家重点实验室成都610031 上海交通大学机械系统与振动国家重点实验室上海200240

重大装备制造业是国民经济的支柱,也是关系到国家安全的战略性产业,而重大机械装备的运行安全一直是备受关注的焦点。机械设备由于工作环境恶劣、工况复杂,其关键部件容易受损,导致设备性能退化,甚至造成设备崩溃。健康状态监测和故障... 详细信息

重大装备制造业是国民经济的支柱,也是关系到国家安全的战略性产业,而重大机械装备的运行安全一直是备受关注的焦点。机械设备由于工作环境恶劣、工况复杂,其关键部件容易受损,导致设备性能退化,甚至造成设备崩溃。健康状态监测和故障诊断是保证重大机械装备安全运行的必要手段。通过信号分解可以抑制机械振动信号中的环境噪声和无关成分干扰,从而有效提取故障特征,因此信号分解在机械故障诊断中发挥着关键作用。目前,围绕信号分解理论及其在机械故障诊断中的应用,国内外学者开展了大量研究工作。首先,从时域、频域和时频域三个方面系统综述了国内外学者对信号分解理论的研究现状;其次,从轴承、齿轮和转子碰摩三个方面详细梳理了信号分解在机械故障诊断中的应用研究现状;最后,归纳总结了信号分解及其在机械故障诊断应用中面临的挑战。

关键词：状态监测故障诊断信号分解轴承故障转子碰摩

基于瞬时频率估计与Vold-Kalman滤波的铣削颤振识别

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振动与冲击 2018年第16期37卷 70-76页

作者：汪晓姗彭志科陈是扦上海交通大学机械系统与振动国家重点实验室上海200240

颤振严重制约了高速铣削加工效率。动态铣削力信号具有非线性、非平稳的特点,常规的信号分解方法难以处理该类信号。提出了一种基于瞬时频率估计和Vold-Kalman滤波的多分量信号分解方法,并运用该信号分解方法识别颤振。基于频谱集中性... 详细信息

颤振严重制约了高速铣削加工效率。动态铣削力信号具有非线性、非平稳的特点,常规的信号分解方法难以处理该类信号。提出了一种基于瞬时频率估计和Vold-Kalman滤波的多分量信号分解方法,并运用该信号分解方法识别颤振。基于频谱集中性指标估计信号的瞬时频率参数;用Vold-Kalman滤波器提取对应参数的各信号分量;由于颤振时铣削力信号的能量分布在频域发生变化,由此引入能量熵的定义。采用分解得到的子信号能量熵变化来识别颤振。实验分析表明该方法有效可行。

关键词：铣削颤振频谱集中性指标 Vold-Kalman滤波能量分布

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激光参数及激光超声探测方法对超声信号影响

红外与激光工程 2014年第5期43卷 1433-1437页

作者：宋燕星王晶冯其波陈士谦北京交通大学发光与光信息技术教育部重点实验室北京100044 防灾科技学院防灾仪器系河北三河065201

文中通过激光超声激发过程理论模型,获得激光超声信号的波形特点,并分析相关参数对激发超声信号的影响。应用两种不同的激光超声探测方法对激光超声信号进行探测,即分别采用超声探头和基于双波混合干涉的光学探测方式搭建两种实验装置... 详细信息

文中通过激光超声激发过程理论模型,获得激光超声信号的波形特点,并分析相关参数对激发超声信号的影响。应用两种不同的激光超声探测方法对激光超声信号进行探测,即分别采用超声探头和基于双波混合干涉的光学探测方式搭建两种实验装置。实验针对入射激光参数对激发超声信号的影响及两种探测方法获得激光超声信号的特点进行分析。通过实验验证了理论分析结果,得出入射激光参数会影响激发超声的幅度,而基于双波混合干涉的光学探测方式可以获得更为完整的超声波形信息。

关键词：激光超声脉冲激光双波混合干涉光学探测

Fabrication of Silane and Desulfurization Ash Composite Modified Polyurethane and Its Interfacial Binding Mechanism

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Journal of Wuhan University of Technology(Materials Science) 2024年第2期39卷 288-297页

作者：吴旺华 chen Shuichang YE Haodong 李世迁 LIN Yuanzhi 陈庆华 XIAO Liren College of Chemistry and Materials Science Fujian Normal UniversityFuzhou 350117China College of Materials and Package Engineering Fujian Provincial Key Lab of Coastal Basin EnvironmentFujian Polytechnic Normal UniversityFuqing 350300China College of Agriculture Guangxi UniversityGuangxi 530004China

Polyurethane/desulfurization ash(PU/DA)composites were synthesized using"one-pot method",with the incorporation of a silane coupling agent(KH550)as a"molecular bridge"to facilitate the integration of DA as hard segments into the PU molecular *** effects of DA content(φ)on the mechanical properties,thermal stability,and hydrophobicity of PU,both before and after the addition of KH550,were thoroughly *** results of microscopic mechanism analysis confirmed that KH550 chemically modified the surface of DA,facilitating its incorporation into the polyurethane molecular chain,thereby significantly enhancing the compatibility and dispersion of DA within the PU *** the mass fraction of modified DA(MDA)reached 12%,the mechanical properties,thermal stability,and hydrophobicity of the composites were substantially improved,with the tensile strength reaching 14.9 MPa,and the contact angle measuring 100.6°.

关键词： polyurethane silane coupling agent desulfurization ash modification mechanical property hydrophobicity thermal stability