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Passive activity enhances residual control ability in patients with complete spinal cord injury

Neural Regeneration Research 2025年第8期20卷 2337-2347页

作者： Yanqing Xiao Mingming Gao Zejia He Jia Zheng Hongming Bai Jia-Sheng Rao Guiyun Song Wei Song Xiaoguang Li beijing key laboratory for Biomaterials and Neural Regeneration Beijing Advanced Innovation Center for Biomedical EngineeringSchool of Biological Science and Medical EngineeringBeihang UniversityBeijingChina Department of Rehabilitation Evaluation China Rehabilitation Research CenterBeijingChina Cardiac Center Beijing Children’s HospitalCapital Medical UniversityBeijingChina The State key laboratory of Virtual Reality technology and Systems Beihang UniversityBeijingChina Department of Rehabilitation Engineering China Rehabilitation Science InstituteBeijingChina

Patients with complete spinal cord injury retain the potential for volitional muscle activity in muscles located below the spinal injury ***,because of prolonged inactivity,initial attempts to activate these muscles may not effectively engage any of the remaining neurons in the descending pathway.A previous study unexpectedly found that a brief clinical round of passive activity significantly increased volitional muscle activation,as measured by surface *** this study,we further explored the effect of passive activity on surface electromyographic signals during volitional control tasks among individuals with complete spinal cord *** patients with chronic complete thoracic spinal cord injury were *** electromyography data from eight major leg muscles were acquired and compared before and after the passive activity *** results indicated that the passive activity led to an increased number of activated volitional muscles and an increased frequency of *** the cumulative root mean square of surface electromyography amplitude for volitional control of movement showed a slight increase after passive activity,the difference was not statistically *** findings suggest that brief passive activity may enhance the ability to initiate volitional muscle activity during surface electromyography tasks and underscore the potential of passive activity for improving residual motor control among patients with motor complete spinal cord injury.

关键词： complete spinal cord injury cycle training epidural electrical stimulation motor training passive activity physiological state spinal cord circuit surface electromyography volitional control task

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New Measurement Method for Spline Shaft Rolling Performance Evaluation using Laser Displacement Sensor

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Chinese Journal of Mechanical Engineering 2018年第4期31卷 124-132页

作者： Hong-Wei Li Zhi-Qiang Liang Jia-Jie Pei Li Jiao Li-Jing Xie Xi-Bin Wang key laboratory of fundamental science for advanced machining Beijing Institute of Technology beijing North Vehicle Group Corporation

In order to control the quality of spline shaft in rolling process, an efficient measurement method for rolling performance evaluation is essential. Here, a newly developed on-machine non-contact measurement prototype based on laser displacement sensor and rotary encoder is proposed. The prototype is intended for the automated evaluation of the spline shaft rolling performance by measuring the dimensional change of tooth root, which is correlated with the surface residual stress and micro-hardness. Laser displacement sensor and rotary encoder are used to record the polar radius and polar angle of each point on measuring section. Data are displayed in a polar coordinate system and fitted in a gear. Through multipoint curvature method, the roots of spline shaft are recognized automatically. Then, the dimensional change can be calculated by fitting the radius of the tooth root circle before and after rolling. Systematic error covering offset error is also analyzed and calibrated. At last, measurement test results show that the system has advantages of simple structure, high measurement precision(radius error < 0.6 μm), high measurement efficiency(measuring time < 2 s) and automatic control ability, providing a new opportunity for the efficient evaluation of various spline shafts in high-precision mechanical processing.

关键词： Laser measurement Spline shaft Rolling performance Dimensional change

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Mesoscale fabrication of a complex surface for integral impeller blades

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Frontiers of Mechanical Engineering 2017年第1期12卷 116-131页

作者： Xibin WANG Tianfeng ZHOU Lijing XIE Li JIAO Zhibing LIU Zhiqiang LIANG Pei YAN key laboratory of fundamental science for advanced machining Beijing Institute of Technology Beijing 100081 China

Integral impeller is the most important compo- nent of a mini-engine. However, the machining of a mesoscale impeller with a complex integral surface is difficult because of its compact size and high accuracy requirement. A mesoscale component is usually manufac- tured by milling. However, a conventional milling tool cannot meet the machining requirements because of its size and stiffness. For the fabrication of a complex integral impeller, a micro-ball-end mill is designed in accordance with the non-instantaneous-pole envelope principle and manufactured by grinding based on the profile model of the helical groove and the mathematical model of the cutting edge curve. Subsequently, fractal theory is applied to characterize the surface quality of the integral impeller. The fractal theory-based characterization shows that the completed mesoscale integral impeller exhibits a favorable performance in terms of mechanical properties and morphological accuracy.

关键词： mesoscale fabrication micro-milling tool,mesoscale milling impeller blade

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Strain transfer mechanism of passive wireless surface acoustic wave torque sensors using shear lag theory

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Journal of beijing institute of technology 2011年第2期20卷 221-226页

作者：张运涛徐春广潘勤学刘婧李喜朋 key laboratory of fundamental science for advanced machining.beijing institute of technology

A shear-lag theory was developed to investigate the strain transfer from the metal substrate to the surface acoustic wave （SAW） resonator through a bonding layer. A three-layer model of host structure-adhesive layer-resonator layer was established. The strain transfer was theoretically analyzed, and the main factors impacting the SAW sensor measurement were studied. The relationship between the sensor response and the individual effect of all these factors under static loads was discussed. Results showed that better accuracy could be achieved with increase in the adhesive stiffness or resonator length, or decrease in the adhesive thickness. The values of the strain transfer rate calculated from the analytical model agreed well with that from the available experiment data.

关键词： passive wireless surface acoustic wave (SAW) torque strain transfer shear lag

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Analysis and experiment of cross-section flattening incoreless tube bending

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Journal of beijing institute of technology 2014年第1期23卷 37-41页

作者：贾美慧唐承统刘检华 key laboratory of fundamental science for advanced machining Beijing Institute of Technology

In order to predict the flattening rate of the cross-section accurately during the tube ben- ding, the generation principle, the solution and the influence factor of the cross-section flattening were studied. On the basis of the plane-stress and the assumption that the plastic volume is con- stant, three-dimensionai strain formulas were established in consider of the cross-section flattening. Considering the wail-thickness change, the approximate calculation formulas of short axis flattening rate were deduced, with the outer diameter and the inner diameter as parameters. Because different materials have different cross-section flattening rates, a material correction factor was introduced to modify the formula based on experiments. Finally, the validity of the theoretical formulas was proved according to the calculation and the experiment results, which can provide a reference for the forming quality prediction in tube bending.

关键词： coreless tube bending cross-section flattening wall-thickness variation change-rate ofshort axis

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High-energy-density lithium manganese iron phosphate for lithium-ion batteries: Progresses, challenges, and prospects

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Journal of Energy Chemistry 2025年第01期 1-17页

作者： Bokun Zhang Xiaoyun Wang Shuai Wang Yan Li Libo Chen Handong Jiao Zhijing Yu Jiguo Tu State key laboratory of advanced Metallurgy University of Science and Technology Beijing Research institute for Intelligent Wearable Systems The Hong Kong Polytechnic University institute of advanced Structure technology Beijing Institute of Technology

The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion *** manganese iron phosphate (LiMnxFe1-xPO4) has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy *** LiMnxFe1-xPO4has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and Li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap *** review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of LiMnxFe1-xPO4to analyze reaction processes accurately and guide material ***,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of LiMnxFe1-xPO4,including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology ***,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are *** importantly,it is expected to provide key insights into the development of high-performance and stable LiMnxFe1-xPO4materials,to achieve practical energy storage requirements.

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Research Review of Principles and Methods for Ultrasonic Measurement of Axial Stress in Bolts

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Chinese Journal of Mechanical Engineering 2020年第1期33卷 44-59页

作者： Qinxue Pan Ruipeng Pan Chang Shao Meile Chang Xiaoyu Xu School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China key laboratory of fundamental science for advanced machining Beijing Institute of TechnologyBeijing 100081China

Bolts are important fasteners indispensable in the manufacturing field for their advantages, which include convenient assembly and disassembly, easy maintenance, refastenability to prevent looseness, and the avoidance of a phase change in the connected material composition. The precise control of the tightening force in bolts is closely related to the safety and reliability of the connected equipment or structure. Although there are many methods for estimating the tightening force applied to a bolt during assembly, poor accuracy in controlling the preload during the tightening process and a lack of monitoring to determine the residual axial force in service remain issues in evaluating the safety of bolted assemblies. As a nondestructive testing technology, ultrasonic measurement can be applied to successfully address these issues. In order to help researchers understand the theoretical basis and technological development in this field and to equip them to conduct further in-depth research, in this review, the basic knowledge describing the state of stress and deformation of bolts, as well as conventional testing methods are summarized and analyzed. Then, through a review of recent research of the ultrasonic measurement of the axial stress in bolts, the influence of the e ective stressed length and temperature are analyzed and proposed methods of calibration and compensation are reviewed. In order to avoid coupling errors caused by traditional piezoelectric transducers, two newly proposed ultrasonic coupling technologies, the electromagnetic acoustic transducer(EMAT) and the permanent mounted transducer system(PMTS), are reviewed. Finally, the new direction of research of the detection of residual axial stress in in-service bolts that have been assembled to yield is discussed.

关键词： Bolted connections Axial stress Ultrasonic waves Influencing factors Coupling techniques

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Modeling of the minimum cutting thickness in micro cutting with consideration of the friction around the cutting zone

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Frontiers of Mechanical Engineering 2020年第1期15卷 81-88页

作者： Tianfeng ZHOU Ying WANG Benshuai RUAN Zhiqiang LIANG Xibin WANG key laboratory of fundamental science for advanced machining Beijing Institute of TechnologyBeijing 100081China School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081China

Friction modeling between the tool and the workpiece plays an important role in predicting the minimum cutting thickness during TC4 micro machining and finite element method(FEM)cutting *** this study,a new three-region friction modeling is proposed to illustrate the material flow mechanism around the friction zone in micro cutting;estimate the stress distributions on the rake,edge,and clearance faces of the tool;and predict the stagnation point location and the minimum cutting *** friction modeling is established by determining the distribution of normal and shear ***,it is applied to calculate the stagnation point location on the edge face and predict the minimum cutting *** stagnation point and the minimum cutting thickness are also observed and illustrated in the FEM *** cutting experiments are conducted to validate the accuracy of the friction and the minimum cutting thickness *** results show that the proposed friction model illustrates the relationship between the normal and sheer stress on the tool surface,thereby validating the modeling method of the minimum cutting thickness in micro cutting.

关键词： tool friction minimum cutting thickness finite element method tool edge radius micro cutting

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Recent advancements in optical microstructure fabrication through glass molding process

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Frontiers of Mechanical Engineering 2017年第1期12卷 46-65页

作者： Tianfeng ZHOU Xiaohua LIU Zhiqiang LIANG Yang LIU Jiaqing XIE Xibin WANG key laboratory of fundamental science for advanced machining Beijing Institute of Technology Beijing 100081 China School of Mechanical Engineering Beijing Institute of TechnologyBeijing 100081 China

Optical microstructures are increasingly applied in several fields, such as optical systems, precision measurement, and microfluid chips. Microstructures include microgrooves, microprisms, and microlenses. This paper presents an overview of optical microstructure fabrication through glass molding and highlights the applications of optical microstructures in mold fabrication and glass molding. The glass-mold interface friction and adhesion are also discussed. Moreover, the latest advance- ments in glass molding technologies are detailed, including new mold materials and their fabrication methods, viscoelastic constitutive modeling of glass, and micro- structure molding process, as well as ultrasonic vibration- assisted molding technology.

关键词： optical microstructure microgroove micro-lens glass molding process single-point diamond cutting

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Investigation on the cutting force of high-speed milling of high volume fraction of SiCp/Al composites with PCD tools

Investigation on the cutting force of high-speed milling of ...

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第八届中国功能材料及其应用学术会议

作者： PENG Song XIE Li-jing WANGXi-bin FU Na-xin SHI Xing-kuan key laboratory of fundamental science for advanced machining Beijing Institute of Technology

ISBN: (纸本)9783037859698

High-speed milling tests for 65vol%SiCp/6063A1 composites were performed by polycrystalline diamond(PCD) tools,response surface methodology was utilized in this study,and a cutting force model was developed through response surface methodology,which contained some important parameters such as cutting speed,cutting feed rate,cutting depth and cutting *** analysis of variance(ANOVA) indicated that the proposed mathematical model can adequately describe the relationship between cutting force and cutting process *** results show that cutting depth is the biggest important factor of milling force,and cutting feed rate is the second important factor,cutting speed is the third;milling force would not increase with the increasing of cutting width.

关键词： High-speedmilling 65vol%SiCp/6063Al composites PCD,Response surface methodology Cutting force

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