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Science China(Technological Sciences) 2018年第8期61卷 1184-1196页

作者： YANG Rui jin yulin HOU Lei CHEN YuShu School of Astronautics Harbin Institute of Technology School of Energy Science and Engineering Harbin Institute of Technology

The studies on dynamics of a fault bearing system are prevalent in recent years, however, we are studying a completely different frequency range than the one where the bearing faults are best seen. Considering a local defect on outer raceway,a two-degree-of-freedom analytical model of a rigid-rotor ball bearing system is established. Three pulse force models are introduced to simulate the local defect. The frequency domain method—harmonic balance method with alternating frequency/time domain technique (HB-AFT) is used to calculate the response in a large frequency range. By comparing the performance at different frequencies, the fault systems with different defect models and parameters reveal the super-harmonic resonances,and the reasons for this phenomenon are uncovered as well. Finally, the theoretical calculation is verified qualitatively by the experimental results, through comparing the frequency spectrums of the defective bearing rotor system to the fault-free ***, the super-harmonic resonances can be regarded as a dynamic feature. Besides, the obvious super-harmonic resonances indicate the magnification of the harmonics of the "characteristic defect frequency" for outer race in the corresponding speed regions, which may be helpful for the diagnosis of a rotor ball bearing system with a local defect.

关键词： rotor bearing system local defect super-harmonic resonance HB-AFT method

Multiscale Theories and Applications:From Microstructure Design to Macroscopic Assessment for Carbon Nanotubes Networks

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Chinese Journal of Mechanical Engineering 2023年第3期36卷 18-35页

作者： Jiachao Ji yulin jin Anping Hua Chunhua Zhu Junhua Zhao Jiangsu Key Laboratory of Advanced Food Manufacturing Equipment and Technology Jiangnan UniversityWuxi 214122China Institute of Mechanics and Advanced Materials School of Mechanical EngineeringJiangnan UniversityWuxi 214122China

Carbon nanotube(CNT)networks enable CNTs to be used as building blocks for synthesizing novel advanced materials,thus taking full advantage of the superior properties of individual *** analyses have to be adopted to study the load transfer mechanisms of CNT networks from the atomic scale to the macroscopic scale due to the huge computational *** them,fully resolved structural features include the graphitic honeycomb lattice(atomic),inter-tube stacking(nano)and assembly(meso)of *** an atomic scale,the elastic properties,ultimate stresses,and failure strains of individual CNTs with distinct chiralities and radii are obtained under various loading conditions by molecular *** dependence of the cohesive energies on spacing distances,crossing angles,size and edge effects between two CNTs is analyzed through continuum modeling in *** mesoscale models,which neglect the atomic structures of individual CNTs but retain geometrical information about the shape of CNTs and their assembly into a network,have been developed to study the multi-level mechanism of material deformation and microstructural evolution in CNT networks under stretching,from elastic elongation,strengthening to damage and *** paper summarizes the multiscale theories mentioned above,which should provide insight into the optimal assembling of CNT network materials for elevated mechanical performance.

关键词： Carbon nanotube networks Hierarchical structures Multiscale theories Mesoscale model

A new nonlinear force model to replace the Hertzian contact model in a rigid-rotor ball bearing system

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Applied Mathematics and Mechanics(English Edition) 2018年第3期39卷 365-378页

作者： yulin jin Zhenyong LU Rui YANG Lei HOU Yushu CHEN School of Astronautics Harbin Institute of Technology School of Energy Science and Engineering Harbin Institute of Technology

A new nonlinear force model based on experimental data is proposed to replace the classical Hertzian contact model to solve the fractional index nonlinearity in a ball bearing system. Firstly, the radial force and the radial deformation are measured by statics experiments, and the data are fitted respectively by using the Hertzian contact model and the cubic polynomial model. Then~ the two models are compared with the approximation formula appearing in Aeroengine Design Manual. In consequence, the two models are equivalent in an allowable deformation range. After that, the relationship of contact force and contact deformation for single rolling element between the races is cal- culated based on statics equilibrium to obtain the two kinds of nonlinear dynamic models in a rigid-rotor ball bearing system. Finally~ the displacement response and frequency spectrum for the two system models are compared quantitatively at different rotational speeds, and then the structures of frequency-amplitude curves over a wide speed range are compared qualitatively under different levels of radial clearance, amplitude of excitation, and mass of supporting rotor. The results demonstrate that the cubic polynomial model can take place of the Hertzian contact model in a range of deformation.

关键词： rolling element bearing, Hertzian contact, fractional index cubic polyno-miali rotor ball bearing system

The Applications of Order Reduction Methods in Nonlinear Dynamic Systems

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Sound & Vibration 2020年第2期54卷 113-125页

作者： Nan Wu Kuan Lu yulin jin Haopeng Zhang Yushu Chen Institute of Vibration Engineering Northwestern Polytechnical UniversityXi’an710072China School of Astronautics Harbin Institute of TechnologyHarbin150001China School of Automation Engineering University of Electronic Science and Technology of ChinaChengdu611731China

Two different order reduction methods of the deterministic and stochastic systems are discussed in this ***,the transient proper orthogonal decomposition(T-POD)method is introduced based on the high-dimensional nonlinear dynamic *** optimal order reduction conditions of the T-POD method are provided by analyzing the rotor-bearing system with pedestal looseness fault at both *** efficiency of the T-POD method is verified via comparing with the results of the original ***,the polynomial dimensional decomposition(PDD)method is applied to the 2 DOFs spring system considering the uncertain stiffness to study the amplitude-frequency *** numerical results obtained by the PDD method agree well with the Monte Carlo simulation(MCS)*** results of the PDD method can approximate to MCS better with the increasing of the polynomial ***,the Uniform-Legendre polynomials can eliminate perturbation of the PDD method to a certain extent via comparing it with the Gaussian-Hermite polynomials.

关键词： Uncertainty T-POD method PDD method rotor spring

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民航客机油箱建模与油量传感器姿态误差修正

北京航空航天大学学报 2005年第2期31卷 218-222页

作者：金宇林庄达民杨钦北京航空航天大学计算机学院北京100083 北京航空航天大学航空科学与工程学院北京100083

实现民航客机的飞机油箱建模 ,提出对油箱的油量传感器示数的姿态误差进行修正的算法 .建模过程基于二维限定Delaunay三角剖分和插值 ,生成油箱的表面 .利用油量传感器错误示数和当前飞行姿态角 ,利用油箱表面三角网格 ,将油箱内含油体... 详细信息

实现民航客机的飞机油箱建模 ,提出对油箱的油量传感器示数的姿态误差进行修正的算法 .建模过程基于二维限定Delaunay三角剖分和插值 ,生成油箱的表面 .利用油量传感器错误示数和当前飞行姿态角 ,利用油箱表面三角网格 ,将油箱内含油体积进行三维三棱柱剖分和三维四面体剖分 .计算四面体体积之和求得油箱正确的含油量 .与当前正在使用的切片算法在效率和使用范围方面进行深入比较与分析 .实现民航客机油箱三维建模 ,并且利用已建立的模型修正其油量传感器示数姿态误差 .算法优于切片算法 .

关键词：民航油箱油量传感器姿态误差三角网格

航空发动机双转子系统叶片-机匣碰摩故障模拟

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航空学报 2022年第12期43卷 492-505页

作者：靳玉林刘治汶陈予恕电子科技大学自动化工程学院成都611731 西南交通大学机械工程学院成都610031 哈尔滨工业大学航天学院哈尔滨150001

叶片-机匣碰摩严重影响航空发动机的性能、可靠性及安全性。考虑叶片-机匣碰摩、轴承非线性、联轴器不对中及高低压转子不平衡,利用有限元法建立双转子系统的非线性动力学模型;然后利用模态综合法缩减系统自由度,数值求解降阶模型的非... 详细信息

叶片-机匣碰摩严重影响航空发动机的性能、可靠性及安全性。考虑叶片-机匣碰摩、轴承非线性、联轴器不对中及高低压转子不平衡,利用有限元法建立双转子系统的非线性动力学模型;然后利用模态综合法缩减系统自由度,数值求解降阶模型的非线性振动响应,分析叶片-机匣碰摩故障响应特征。数值与实验结果表明:航空发动机双转子系统为多激励非线性系统,系统振动响应频率成分复杂,包括高低压转轴频率、多倍频、组合频率及其他复杂频率;当叶尖间隙较大时,叶片-机匣碰摩可能为局部碰摩,故障特征频率为叶片通过频率及其倍频,并在叶片通过频率两侧存在高低压转轴频率的调制边频带;当叶尖间隙较小时,叶片-机匣碰摩可能发生全周碰摩,呈现出由干摩擦引起的强烈自激振动。研究结果可为航空发动机双转子系统的叶片-机匣碰摩故障诊断及叶尖间隙设计提供一定参考。

关键词：航空发动机双转子系统叶片-机匣碰摩有限元法模态综合法

Effect of Ginseng on the Symptoms and Hemodynamics in Elders

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Effect of Ginseng on the Symptoms and Hemodynamics in Elders

血府逐瘀汤联合苍龟探穴刺法治疗中风后偏瘫患者的疗效观察

全国中青年中西医结合学术（英语）交流会议

作者： Li-Yajun, Yang-lianxing, Wei-yulin, jin-Ming, jin-Enyuan (China-Japan Friendship Hospital, Clinical Medical Science, Beijing 100029) Nam-Kiyeul (Korea Ginseng & Tobacco Research Institute)

Objective: To observe the effect of Ginseng on the hemodynamics of healthy elders before and after tread mill. Method: Random, double-blind and control design. Seventy-five 50-70 years old volunteers without organic disease were divided into two groups, Ginseng group and Control group. Before and after administration 4 weeks, the symptoms were asked, and hemodynamic parameters such as pump function, systolic function, preload and afterload, were recorded before and after treadmill 1,5,10 minutes by the method of thoracic impedance cardiograph. Result: 1, Ginseng could improve life quality on elder. 2, Ginseng had obvious effect of increasing PEP, PEP/LVET, PCWP, compared with control group, P<0.05. 3, After tread mill, in Ginseng group, the change rate of HR, SV were much lowered than that in control group. And EF, LVET, PEP/LVEDP, in person of group were recovered much quickly. Conclusion: The tonic herb, Ginseng can improve the life quality of healthy old person through its promoting circulation function, which are increasing both the systolic function and the preload.

关键词： Hemodynamics Aged Ginseng

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中医临床研究 2019年第25期11卷 16-18页

作者：金玉林湖北省安陆市普爱医院

目的:观察血府逐瘀汤联合苍龟探穴刺法治疗中风后偏瘫患者的临床疗效。方法:选取我院78例中风后偏瘫患者,采用随机数字表法分组,各39例。对照组予以苍龟探穴刺法治疗,观察组在对照组基础上予以血府逐瘀汤治疗。对比两组临床治疗效果、... 详细信息

目的:观察血府逐瘀汤联合苍龟探穴刺法治疗中风后偏瘫患者的临床疗效。方法:选取我院78例中风后偏瘫患者,采用随机数字表法分组,各39例。对照组予以苍龟探穴刺法治疗,观察组在对照组基础上予以血府逐瘀汤治疗。对比两组临床治疗效果、治疗前、治疗4周后美国国立卫生研究院卒中量表(National Institutes of Health Stroke Scale,NIHSS)评分、Oswestry功能障碍指数量表(ODI)评分、Barthel指数量表(BI)评分、简明健康状况调查量表(SF-36)评分。结果:观察组治疗总有效率[94.87%(37/39)]较对照组[76.92%(30/39)]高(P<0.05);治疗4周后观察组NIHSS评分、ODI评分较对照组低(P<0.05);治疗4周后观察组BI评分、SF-36评分较对照组高(P<0.05)。结论:血府逐瘀汤联合苍龟探穴刺法治疗中风后偏瘫患者,疗效显著,可减轻神经功能缺损,促进上下肢运动功能恢复,增强患者日常生活能力,提高生活质量。

关键词：中风偏瘫血府逐瘀汤苍龟探穴刺法运动功能

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初中音乐教学中学生学习兴趣激发策略

科教导刊 2019年第5期 136-137页

作者：金玉林常熟市实验中学江苏常熟215500

在新时代下,随着社会的不断进步,国家对教育越来越重视。相对于小学来说,初中增加了几门新的学科,并且面临着中考,因此学习压力更大,而音乐这门学科只是辅助课程,并不参与中考成绩,因此得不到学生的重视。充分调动学生学习音乐的兴趣和... 详细信息

在新时代下,随着社会的不断进步,国家对教育越来越重视。相对于小学来说,初中增加了几门新的学科,并且面临着中考,因此学习压力更大,而音乐这门学科只是辅助课程,并不参与中考成绩,因此得不到学生的重视。充分调动学生学习音乐的兴趣和参与热情是目前应该解决的问题。

关键词：音乐教学学习兴趣激发

三联方案与四联方案在根除难治性***感染中的效果对比分析

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中外医疗 2023年第33期42卷 75-78页

作者：金玉琳高邮市中医医院消化内科江苏高邮225600

目的探究三联方案与四联方案在根除难治性幽门螺杆菌(helicobacter pylori, HP)感染中的效果对比分析。方法便利选取2021年1月—2022年12月高邮市中医医院消化内科收治的98例难治性HP感染患者为研究对象,按照随机数表法分为对照组和... 详细信息

目的探究三联方案与四联方案在根除难治性幽门螺杆菌(helicobacter pylori, HP)感染中的效果对比分析。方法便利选取2021年1月—2022年12月高邮市中医医院消化内科收治的98例难治性HP感染患者为研究对象,按照随机数表法分为对照组和观察组,各49例。对照组采用三联方案治疗,观察组采用四联方案治疗。比较两组患者的根治率、炎性因子水平、症状积分、不良反应发生率。结果采用符合方案分析(per-protocol analysis, PP)方法和意向性治疗分析(intention to treat analysis, ITT)方法可知,观察组的根治率均高于对照组,但差异无统计学意义(P>0.05)。治疗后,观察组反酸暖气(0.91±0.10)分、腹痛(0.87±0.15)分、腹胀(0.92±0.09)分等症状积分及肿瘤坏死因子-α(tumor necrosis factor, TNF-α)、血清降钙素原(procalcitonin, PCT)、白介素-8(interleukin-8, IL-8)水平均低于对照组,差异有统计学意义(P0.05)。结论三联方案和四联方案根治难治性HP感染均可发挥一定的疗效,四联方案相较于三联方案可更好地降低患者的炎症因子水平,改善患者的临床症状,综合考虑采用四联该方案的优势性更高。

关键词：三联方案四联方案难治性HP感染呋喃唑酮枸橼酸铋钾