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A New Differential Operator Method to Study the Mechanical Vibration

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Modern Mechanical Engineering 2012年第3期2卷 65-70页

作者： Quansheng ji Xiaomei ji linhong ji Yuxi Zheng Department of Mathematical Sciences Yeshiva University New York USA Shandong Iron and Steel Company Ltd. Jinan China The State Key Laboratory of Tribology Tsinghua University Beijing China

In this paper, we propose a unified differential operator method to study mechanical vibrations, solving inhomogeneous linear ordinary differential equations with constant coefficients. The main advantage of this new method is that the differential operator D in the numerator of the fraction has no effect on input functions (i.e., the derivative operation is removed) because we take the fraction as a whole part in the partial fraction expansion. The method in various variants is widely implemented in related fields in mechanics and engineering. We also point out that the same mistakes in the differential operator method are found in the related references [1-4].

关键词： New Differential Operator Method Mechanical Vibration (Torsional Vibration of Rolling-Mill) Torque Amplification Factor Model Analysis Method Laplace Transform

Cell Mechanics Regulates the Dynamic Anisotropic Remodeling of Fibril Matrix at Large Scale

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Research 2024年第3期2023卷 401-415页

作者： Mingxing Ouyang Yanling Hu Weihui Chen Hui Li Yingbo ji Linshuo Qiu Linlin Zhu Baohua ji Bing Bu linhong Deng Institute of Biomedical Engineering and Health Sciences School of Medical and Health Engineering and School of PharmacyChangzhou UniversityChangzhou213164China Institute of Biomechanics and Applications Department of Engineering MechanicsZhejang UniversityHangzhou310027China.

Living tissues often have anisotropic and heterogeneous organizations, in which developmental processes are coordinated by cells and extracellular matrix modeling. Cells have the capability of modeling matrix in long distance;however, the biophysical mechanism is largely unknown. We investigated the dynamic remodeling of collagen I (COL) fibril matrix by cell contraction with designed patterns of cell clusters. By considering cell dynamic contractions, our molecular dynamics simulations predicted the anisotropic patterns of the observed COL bundling in experiments with various geometrical patterns without spatial limitation. The pattern of COL bundling was closely related to the dynamic remodeling of fibril under cell active contraction. We showed that cell cytoskeletal integrity (actin filaments and microtubules), actomyosin contractions, and endoplasmic reticulum calcium channels acting as force generations and transductions were essential for fiber bundling inductions, and membrane mechanosensory components integrin and Piezo played critical roles as well. This study revealed the underlying mechanisms of the cell mechanics-induced matrix remodeling in large scales and the associated cellular mechanism and should provide important guidelines for tissue engineering in potential biomedical applications.

关键词： contraction Dynamic Matrix

Simulation of cold plasma in a chamber under high- and low-frequency voltage conditions for a capacitively coupled plasma

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Journal of Semiconductors 2012年第10期33卷 42-47页

作者：郝道欣程嘉季林红孙钰淳 Department of Precision Instruments and Mechanology Tsinghua University

The characteristics of cold plasma,especially for a dual-frequency capacitively coupled plasma（CCP）, play an important role for plasma enhanced chemical vapor deposition,which stimulates further studies using different *** this paper,a 2D fluid model was constructed for N_2 gas plasma simulations with CFD-ACE＋, a commercial multi-physical software ***,the distributions of electric potential（E_（pot））,electron number density（N_e）,N number density（N） and electron temperature（T_e） are described under the condition of high frequency（HF）,13.56 MHz,HF voltage,300 V,and low-frequency（LF） voltage,0 V,particularly in the sheath. Based on this,the influence of HF on N_e is further discussed under different HF voltages of 200 V,300 V,400 V, separately,along with the influence of LF,0.3 MHz,and various LF voltages of 500 V,600 V,700 *** results show that sheaths of about 3 mm are formed near the two electrodes,in which E_（pot） and T_e vary extensively with time and space,while in the plasma bulk E_（pot） changes synchronously with an electric potential of about 70 V and T_e varies only in a small range.N is also modulated by the radio frequency,but the relative change in N is small. N_e varies only in the sheath,while in the bulk it is steady at different time ***,by comparing N_e in the plasma bulk at the steady state,we can see that N_e will increase when HF voltage ***,N_e will slightly decrease with the increase of LF *** the same time,the homogeneity will change in both x and y *** both HF and LF voltages should be carefully considered in order to obtain a high-density,homogeneous plasma.

关键词： plasma CFD-ACE+ HF LF voltage sheath

Triboelectric nanogenerators for human-health care

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Science Bulletin 2021年第5期66卷 490-511,M0004页

作者： Hao Wang jia Cheng Zhaozheng Wang linhong ji Zhong Lin Wang State Key Laboratory of Tribology Department of Mechanical EngineeringTsinghua UniversityBeijing 100084China Beijing Institute of Nanoenergy and Nanosystems Chinese Academy of SciencesBeijing 100083China School of Materials Science and Engineering Georgia Institute of TechnologyAtlantaGA 30332-0245USA

Since the world’s first triboelectric nanogenerator(TENG) was proposed in 2012, numerous TENG-based devices and equipment have sprung up in various fields. In particular, TENG has great potential in the field of human-health care due to its small size, self-powered and low cost. With the continuous deepening of TENG research, its structure, function and technical concept are becoming more and more abundant. In order to summarize the progress and development status of TENG in health care, based on the different types of applications subdirection, this paper reviews the TENG-based research work of this field in recent eight years. The characteristics of various types of TENG-based applications and their corresponding technologies are introduced and analyzed, under the comparison of their structure and performance. This review is dedicated to provide reference and inspiration for the future development and innovation of TENG for health care.

关键词： Triboelectric nanogenerator Medical Health care Self-powered

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无动力储能式截瘫助行外骨骼弹簧刚度优化

清华大学学报（自然科学版） 2017年第11期57卷 1179-1184页

作者：关鑫宇季林红王人成清华大学机械工程系摩擦学国家重点实验室智能与生物机械分室北京100084

无动力储能式截瘫助行外骨骼为不同身高、体重和损伤情况的截瘫患者提供精准化助行,储能弹簧作为外骨骼标准元件,其刚度为固定值。该文针对该外骨骼储能弹簧刚度参数选择问题,建立了截瘫患者穿戴无动力储能式截瘫助行外骨骼单侧下肢从... 详细信息

无动力储能式截瘫助行外骨骼为不同身高、体重和损伤情况的截瘫患者提供精准化助行,储能弹簧作为外骨骼标准元件,其刚度为固定值。该文针对该外骨骼储能弹簧刚度参数选择问题,建立了截瘫患者穿戴无动力储能式截瘫助行外骨骼单侧下肢从站立中期到站立后期动力学模型,得到人体髋关节力矩与身高、体重、髋关节角度的关系,并提出以人体髋关节和弹簧力矩之和绝对值的积分为优化目标的弹簧刚度参数优化设计方法。研究发现:不同身高、体重组合情况下,外骨骼弹簧1刚度k1满足正态分布,弹簧2刚度k2不满足正态分布;k1和k2的中位数3 180和1 279N/m作为无动力储能式截瘫助行外骨骼储能弹簧刚度参数,适用于身高和体重在百分位数P1~P99间的患者。

关键词：截瘫行走站立外骨骼储能

基于Simulink的上肢康复训练人机整体建模与分析

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生物医学工程学杂志 2018年第1期35卷 8-14页

作者：刘亚丽季林红清华大学机械工程系摩擦学国家重点实验室智能与生物机械分室北京100084

机器人康复训练是解决中风瘫痪患者康复训练需求的重要方法,康复机器人设定的训练参数对患者能力的适应程度是决定训练能否加快患者康复进程的重要因素。目前临床上的康复训练内容由康复医师对患者进行量表评估并结合自己的经验制定,这... 详细信息

机器人康复训练是解决中风瘫痪患者康复训练需求的重要方法,康复机器人设定的训练参数对患者能力的适应程度是决定训练能否加快患者康复进程的重要因素。目前临床上的康复训练内容由康复医师对患者进行量表评估并结合自己的经验制定,这种经验式的训练方法在康复机器人训练过程中无法实现。为了探讨上肢康复机器人运动训练参数与患者运动能力之间的关系,本文建立了牵引式上肢康复机器人训练的Simulink人机整体模型,并将模型计算的人体肩关节、肘关节运动与实际动作下的肩关节、肘关节运动进行了对照。分析显示仿真结果与实验数据存在明显的相关性,从而证明了模型的准确性。进一步地,本文根据模型仿真结果拟合了人机接触端平面画圆半径与人体肩关节、肘关节主动运动自由度的线性函数关系,为临床上康复机器人制定训练目标提供了量化参考。

关键词： Simulink人机整体模型牵引式上肢康复机器人平面运动训练轨迹

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增强速度滑冰运动员腿部力量的训练方法

清华大学学报（自然科学版） 2008年第2期48卷 200-202,206页

作者：高伟王子羲季林红清华大学精密仪器与机械学系摩擦学国家重点实验室北京100084

为提高运动员的专项力量训练效率和专项运动能力,针对滑冰运动的腿部用力特点,提出了一种减小大腿伸肌离心收缩负荷的腿部力量训练方法,并利用肌电分析的手段,实验比较了在该训练方法和负重深蹲训练方法训练中腿部肌肉活动的差异。结果... 详细信息

为提高运动员的专项力量训练效率和专项运动能力,针对滑冰运动的腿部用力特点,提出了一种减小大腿伸肌离心收缩负荷的腿部力量训练方法,并利用肌电分析的手段,实验比较了在该训练方法和负重深蹲训练方法训练中腿部肌肉活动的差异。结果表明:用该训练方法进行训练时,运动员腿部肌肉的活动状况更接近于滑冰运动中肌肉的活动状况,力量训练的专项化程度更高,更适合于进行腿部专项力量训练。

关键词：专项力量力量训练离心收缩肌电

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用于截瘫患者康复训练的足底轮式驱动外骨骼

清华大学学报（自然科学版） 2017年第6期57卷 597-603页

作者：马青川季林红王人成李伟清华大学机械工程系摩擦学国家重点实验室北京100084

截瘫患者必须依赖辅具才能保证正常生活,而站立和行走是他们最迫切的需求。该文介绍了一种采用机械结构设计的动力下肢外骨骼,旨在帮助截瘫患者实现交替行走并提高其在康复训练中的参与度。该系统主要包括足底轮式驱动外骨骼和无线控制... 详细信息

截瘫患者必须依赖辅具才能保证正常生活,而站立和行走是他们最迫切的需求。该文介绍了一种采用机械结构设计的动力下肢外骨骼,旨在帮助截瘫患者实现交替行走并提高其在康复训练中的参与度。该系统主要包括足底轮式驱动外骨骼和无线控制肘拐2部分。其中外骨骼由置于足底的定制轮毂电机驱动,而肘拐作为辅助器件主要用于保证行走平衡并通过内嵌的无线控制器控制外骨骼行走状态。交替按压左右肘拐上的控制按键可以实现连续行走,而整个行走过程可以完全由使用者实时地掌控。该外骨骼同时设计了电子刹车和最大步长机械限位用以保证使用安全。由一位健康受试者在三维步态分析系统中完成了穿外骨骼和不穿外骨骼情况下的运动对比实验。步态时空参数和运动学曲线表明:该外骨骼可辅助使用者安全而平稳地完成直立行走。

关键词：动力外骨骼截瘫下肢辅具康复器械

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行为-结构演化序参量与运算

农业机械学报 2014年第12期45卷 341-347页

作者：侯悦民 Michel van Tooren 季林红北京信息科技大学机电学院北京100192 清华大学机械工程系北京100084 南卡洛里纳大学航天创新和研究中心哥伦比亚sc29201 清华大学教育部摩擦学重点实验室北京100084

在系统层次研究设计的一般规律,以典型机构为实例,讨论结构演变过程,用宏观序参量加以描述,并通过设计机器人动作规划实现序列序参量运算,通过机构设计实例加以验证;用协同学序参量的概念描述行为-结构映射过程,揭示行为-结构映射的内... 详细信息

在系统层次研究设计的一般规律,以典型机构为实例,讨论结构演变过程,用宏观序参量加以描述,并通过设计机器人动作规划实现序列序参量运算,通过机构设计实例加以验证;用协同学序参量的概念描述行为-结构映射过程,揭示行为-结构映射的内在规律,在此基础上,进一步提出用设计机器人(D-Robot)执行序参量运算实现自动设计和分析,以实现往复运动行为的机构设计为例验证了方法的有效性。提出D-Robot通用模版,并以此为框架编制凸轮机构设计和分析D-Robot动作规划,实现了凸轮机构设计和分析自动设计。输入条件是从动件尖端运动轨迹,输出包括凸轮理论和实际廓线、速度和加速度运动分析、凸轮力分析、动平衡、速度波动及飞轮设计、运动模拟及设计分析报告。

关键词：行为结构映射序参量设计机器人自动设计