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Lower limb motor function assessment based on TensorFlow convolutional neural network and kernel entropy component analysis-local tangent space alignment

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ADVANCES IN MECHANICAL ENGINEERING 2020年第7期12卷

作者： Zhang, Yan Li, SiNing Zhou, Ying Liu, Jian Hebei Univ Technol Sch Artificial Intelligence Tianjin 300310 Peoples R China Hebei Univ Technol Engn Res Ctr Intelligent Rehabil Minist Educ Tianjin Peoples R China Hebei Univ Technol Hebei Key Lab Robot Sensing & Human Robot Interac Tianjin Peoples R China

Motor function assessment of patients and the elderly is crucial to gait assessment and gait rehabilitation. Accuracy of the assessment is affected by clinician's experience. To solve the problem, this article proposes motor function assessment index to assess the motor function of patients. VICON system collects video of subjects when they are walking. And the original gait videos are pre-processed by the pixel-based adaptive segmenter and extracted by the convolutional neural network. The kernel entropy component analysis and local tangent space alignment reduced the dimensions of extracted features, and motor function assessment index is obtained. The Pearson correlation analysis shows that the motor function assessment index and modified gait abnormality rating scale are significantly correlated, and Pearson correlation coefficient is 0.92. These effectiveness results demonstrate that the proposed method has the considerable potential to promote the future design of automatic motor function assessment for clinical rehabilitation research.

关键词： Convolutional neural network lower limb motor function assessment transfer learning kernel entropy component analysis local tangent space alignment

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Printable, flexible, breathable and sweatproof bifunctional sensors based on an all-nanofiber platform for fully decoupled pressure-temperature sensing application

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CHEMICAL ENGINEERING JOURNAL 2023年第Part1期452卷

作者： Wang, Peng Yu, Wei Li, Guoxian Meng, Chuizhou Guo, Shijie Hebei Univ Technol State Key Lab Reliabil & Intelligence Elect Equipm Tianjin 300401 Peoples R China Hebei Univ Technol Hebei Key Lab Smart Sensing & Human Robot Interact Tianjin 300401 Peoples R China Hebei Univ Technol Sch Mech Engn Tianjin 300401 Peoples R China

Flexible bifunctional sensors that mimic the function of human skin are essential as they provide critical interacting information with human and environment for intelligentization. However, the problem of the interference between sensing signals from different stimuli and the deficiency of comfortability for a long-time skin-attaching wearing still exist. Herein, we present an ultrathin and flexible bifunctional sensor based on two measurable parameters of pressure-induced supercapacitance and temperature-induced resistance with neglectable crosstalk between the two. The sensor consists of a planar iontronic supercapacitor underneath a serpentine resistor with assembly of total seven layers integrated on an electrospun thermoplastic polyurethane (TPU)-based nanofiber platform. Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS)-based sensing electrodes are patterned by a direct ink writing method with addition of graphene nanoflakes and Co3O4 nanoparticles to enhance the sensing performance. A high pressure sensitivity (147.19 kPa-1, 0-7 kPa;4.41 kPa-1, 25-85 kPa) and a high temperature sensitivity (0.040 degrees C-1, 25-50 degrees C;0.002 degrees C-1, 50-100 degrees C) are simultaneously achieved. The sensor also has the advantages of humidity inertness, waterproof ability and air permeability, which is breathable to obtain a wearing comfortability. Decoupled pressure-temperature sensing applications of detecting various subtle pressures by objects of different temperatures are demonstrated in a wireless and real-time mode. The proposed bifunctional sensor shows great potential in wearable healthcare monitoring.

关键词： Bifunctional sensor Flexible pressure-temperature sensing Electrospun nanofibers Breathable Sweatproof

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Sensitivity Analysis and Interval Multi Objective Optimization for an Occupant Restraint System Considering Craniocerebral Injury

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JOURNAL OF MECHANICAL DESIGN 2020年第2期142卷 p1-11页

作者： Liu, Qiming Wu, Xingfu Han, Xu Liu, Jie Zhang, Zheyi Guo, Shijie Hebei Univ Technol Sch Elect Engn State Key Lab Reliabil & Intelligence Elect Equip Tianjin 300401 Peoples R China Hunan Univ Coll Mech & Vehicle Engn State Key Lab Adv Design & Mfg Vehicle Body Changsha 410082 Peoples R China Hebei Univ Technol Sch Mech Engn State Key Lab Reliabil & Intelligence Elect Equip Hebei Key Lab Robot Sensing & Human Robot Interac Tianjin 300401 Peoples R China

In vehicle collision accidents, an occupant restraint system (ORS) is crucial to protect the human body from injury, and it commonly involves a large number of design parameters. However, it is very difficult to quantify the importance of design parameters and determine them in the ORS design process. Therefore, an approach of the combination of the proposed approximate sensitivity analysis (SA) method and the interval multi-objective optimization design is presented to reduce craniocerebral injury and improve ORS protection performance. First, to simulate the vehicle collision process and obtain the craniocerebral injury responses, the integrated finite element model of vehicle -occupant (IFEM-VO) is established by integrating the vehicle, dummy, seatbelt, airbag, etc. Then, the proposed approximate SA method is used to quantify the importance ranking of design parameters and ignore the effects of some nonessential parameters. In the SA process, the Kriging meta model characterizing the relationships between design parameters and injury responses is fitted to overcome the time-consuming disadvantage of IFEM-VO. Finally, according to the results of SA, considering the influence of uncertainty, an interval multiobjective optimization design is implemented by treating the brain injury criteria (BRIC, BrIC) as the objectives and regarding the head injury criterion (HIC) and the rotational injury criterion (RIC) as the constraints. Comparison of the results before and after optimization indicates that the maximum values of the translational and rotational accelerations are greatly reduced, and the ORS protection performance is significantly improved. This study provides an effective way to improve the protection performance of vehicle ORS under uncertainty.

关键词： occupant restraint system craniocerebral injury sensitivity analysis interval multi-objective optimization design Kriging metamodel Monte Carlo method uncertainty analysis

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Flexible, stretchable, breathable and sweatproof all-nanofiber iontronic tactile sensor for continuous and comfortable knee joint motion monitoring

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NANO ENERGY 2022年第PartA期103卷

作者： Wang, Peng Liu, Jun Yu, Wei Li, Guoxian Meng, Chuizhou Guo, Shijie Hebei Univ Technol State Key Lab Reliabil & Intelligence Elect Equipm Tianjin 300401 Peoples R China Hebei Univ Technol Hebei Key Lab Smart Sensing & Human Robot Interact Tianjin 300401 Peoples R China Hebei Univ Technol Sch Mech Engn Tianjin 300401 Peoples R China

Running improperly for an extended period of time will induce irreversible damage to knee joints, which can bring about excruciating pains to joggers. Wearable sensors for continual knee-monitoring are highly recom-mended. However, conventional flexible sensors built on airtight substrates are inferior in comfort when wearing for lengthy durations. Herein, a highly flexible and stretchable iontronic tactile sensor is developed on an electrospun thermoplastic polyurethane nanofiber platform. The multilayered, intertwined, nanofiber network housing numerous micro-pores/channels endows the sensor with superior air permeability, sweat inertness, thermal dissipation ability, and biocompatibility, which allows for an extended, comfortable wearing experience. Accrediting the supercapacitive sensing mechanism and porous microstructure, a performance exhibiting a high sensitivity, wide detection range, rapid response, excellent stability and repeatability can be achieved. Prag-matically, a knee-sensor prototype was developed and demonstrated running in real-time and continuously: monitoring a single point of pressure with 3 individual sensor units attached to the rim of the knee and mapping the spatial pressure distribution with an array of sensors covering the whole knee. The health status of the knee could be properly diagnosed, which would be useful for warning of potential knee injuries or to better the form of exercisers.

关键词： Flexible sensor Iontronic tactile sensor Electrospun nanofibers Breathable Sweatproof Knee joint motion monitoring

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Tunable microfluidic standing air bubbles and its application in acoustic microstreaming

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BIOMICROFLUIDICS 2019年第3期13卷 034114-034114页

作者： Liu, Jixiao Li, Bowen Zhu, Tong Zhou, Yidi Li, Shanshan Guo, Shijie Li, Tiejun Hebei Univ Technol Sch Mech Engn Tianjin 300132 Peoples R China Hebei Univ Technol Hebei Key Lab Smart Sensing & Human Robot Interac Tianjin 300132 Peoples R China Hebei Univ Technol State Key Lab Reliabil & Intelligence Elect Equip Tianjin 300132 Peoples R China

Microbubbles are often used in chemistry, biophysics, and medicine. Properly controlled microbubbles have been proved beneficial for various applications by previous scientific endeavors. However, there is still a plenty of room for further development of efficient microbubble handling methods. Here, this paper introduces a tunable, stable, and robust microbubble interface handling mechanism, named as microfluidic standing air bubbles (mu SABs), by studying the multiphysical phenomena behind the gas-liquid interface formation and variation. A basic mu SAB system consists specially structured fluidic channels, pneumatic channels, and selectively permeable porous barriers between them. The mu SABs originate inside the crevice structures on the fluidic channel walls in a repeatable and robust manner. The volumetric variation of the mu SAB is a multiphysical phenomenon that dominated by the air diffusion between the pneumatic channel and the bubble. Theoretical analysis and experimental data illustrate the coupling processes of the repeatable and linear mu SAB volumetric variation when operated under common handling conditions (control pneumatic pressure: -90kPa to 200kPa). Furthermore, an adjustable acoustic microstreaming is demonstrated as an application using the alterable mu SAB gas-liquid interface. Derived equations and microscopic observations elucidate the mechanism of the continuous and linear regulation of the acoustic microstreaming using varying mu SAB gas-liquid interfaces. The mu SAB system provides a new tool to handle the flexible and controllable gas-liquid interfaces in a repeatable and robust manner, which makes it a promising candidate for innovative biochemical, biophysical, and medical applications.

关键词： Gas liquid interfaces Cavitation bubbles Bubble dynamics Microfluidic devices Microchannel Acoustic streaming Fluid bubbles Mass diffusion Acoustofluidics

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Soft-Contact Acoustic Microgripper Based on a Controllable Gas-Liquid Interface for Biomicromanipulations

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SMALL 2021年第49期17卷 2104579-2104579页

作者： Zhou, Yidi Liu, Jixiao Yan, Junjia Guo, Shijie Li, Tiejun Hebei Univ Technol State Key Lab Reliabil & Intelligence Elect Equip Tianjin 300132 Peoples R China Hebei Univ Technol Hebei Key Lab Smart Sensing & Human Robot Interac Tianjin 300132 Peoples R China Hebei Univ Technol Sch Mech Engn Tianjin 300132 Peoples R China

The manipulation of microscale bioentities is desired in many biological and biomedical applications. However, the potential unobservable damage to bioparticles due to rigid contact has always been a source of concern. Herein, a soft-contact acoustic microgripper to handle microparticles to improve the interaction safety is introduced. The system takes advantage of the acoustic-enhanced adhesion of flexible gas-liquid interfaces to capture-release, transport, and rotate the target, such as microbeads (20-65 mu m) and zebrafish embryos (from 950 mu m to 1.4 mm). The gas-liquid interface generated at the tip of a microcapillary can be precisely controlled by a pneumatic pressure source. The gas-liquid interface oscillation excited by acoustic energy imposes coupled radiation force and drag force on the microparticles, enabling multidimensional movements. Experiments with the microbeads are conducted to evaluate the claimed function and quantify the key parameters that influence the manipulation result. Additionally, 250 zebrafish embryos are captured, transported, and rotated. The hatching rate of the 250 manipulated embryos is approximately 98% similar to that of the nonmanipulated group, which proves the noninvasiveness of the method. The derived theories and experimental data indicate that the developed soft-contact microgripper is functional and beneficial for biological and medical applications.

关键词： acoustic tweezers acoustofluidics biomicromanipulation cell transportation and rotation gas-liquid interface

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A conformable, durable, adhesive welded fiber mate for on-skin strain sensing

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CHEMICAL ENGINEERING JOURNAL 2023年第1期457卷

作者： Xie, Xia Liu, Guoqing Li, Haixu Yuan, Wenjing Guo, Shijie Hebei Univ Technol Sch Mat Sci & Engn Tianjin Key Lab Mat Laminating Fabricat & Interfac Tianjin 300130 Peoples R China Hebei Univ Technol Sch Mech Engn State Key Lab Reliabil & Intelligence Elect Equipm Hebei Key Lab Smart Sensing & Human Robot Interact Tianjin 300401 Peoples R China

On-skin electronics have been attracting tremendous attentions due to their potential use for continuous, long-term physical movement detection and physiological signal monitoring. However, developing on-skin strain sensors that can be conformally attached to skin with good breathability and adhesion remains a challenge. Here, we present an ultrathin, lightweight, breathable welded fiber mate-based strain sensor that can be conformally adhered to curved human skin through a sacrificial interlayer. The modulus of the fiber mate is similar to human skin, and its thinness and softness lead to minimum mechanical constraints on skin during deformation (0.03 N at 5 % strain). The welded mate sensor exhibits large stretchability (420 %) and sensing durability due to its double-level elastic structure on both polymer chain and fiber chain levels. It can work over a wide temperature range from 0 to 40 degrees C with almost no temperature interference. After patterned into a serpentine geometry, the welded mate can also be used as a stretchable and conformal gas sensor to detect harmful gases with excellent stability against strain interference.

关键词： Welded fiber mate On-skin electronics Strain sensing Gas sensing MXene

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Graphene-wrapped bimetallic nanoparticles bifunctional electrocatalyst for rechargeable Zn-air battery

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JOURNAL OF ELECTROANALYTICAL CHEMISTRY 2022年 927卷 1页

作者： Zhu, Bo Wan, Tongtao Li, Jing Meng, Chuizhou Du, Xiaohang Liu, Guihua Guan, Yuming Hebei Univ Technol Sch Mech Engn State Key Lab Reliabil & Intelligence Elect Equipm Hebei Key Lab Smart Sensing & Human Robot Interact Tianjin 300130 Peoples R China Hebei Univ Technol Sch Chem Engn & Technol Tianjin Key Lab Chem Proc Safety Tianjin 300130 Peoples R China

Developing efficient and stable bifunctional electrocatalysts towards oxygen evolution/reduction reactions (OER/ORR) is both critical and challenging for the application of zinc-air batteries (ZABs). In this work, a reduced graphene oxide-encapsulated, metal-organic framework (MOF)-derived NiCo bimetallic nanoparti-cles-based bifunctional catalyst (NiCo@rGO) was successfully prepared. The intertwining of flaky rGO and MOF derivatives results in a large specific surface area and abundant pore structure, which is favorable for exposure of active catalytic sites and ensures high electronic conductivity of the catalyst at the same time. The cooperation of cobalt and nickel nanoparticles enriches the active centers and increases the intrinsic cat-alytic activity compared with monometallic Co nanoparticles, leading to enhanced catalytic performance. Benefited from the above advantages, NiCo@rGO exhibits efficient catalytic activities with an oxygen reduc-tion half-wave potential of 0.85 V and oxygen evolution overpotential of 460 mV at 10 mA cm-2. Furthermore, the ZABs with NiCo@rGO exhibits a open-circuit voltage of 1.49 V, a peak power density of as high as 110.45 mW cm-2 and excellent stability over 180 h. This contribution paves a practical avenue to construct bimetal-rGO composites for high-performance ZABs.

关键词： Zinc -air battery NiCo nanoparticles Reduced graphene oxide Bifunctional electrocatalyst

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MOF-derived nitrogen-doped carbon-based trimetallic bifunctional catalysts for rechargeable zinc-air batteries

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NANOTECHNOLOGY 2022年第40期33卷 405403-405403页

作者： Zhu, Bo Li, Jing Hou, Zhanrui Meng, Chuizhou Liu, Guihua Du, Xiaohang Guan, Yuming Hebei Univ Technol Sch Mech Engn Hebei Key Lab Smart Sensing & Human Robot Interac State Key Lab Reliabil & Intelligence Elect Equip Tianjin 300130 Peoples R China Hebei Univ Technol Sch Chem Engn & Technol Tianjin Key Lab Chem Proc Safety Tianjin 300130 Peoples R China

Zinc-air battery (ZAB) is a promising new metal-air energy system, but the large overpotentials of oxygen evolution reaction (OER) and oxygen reduction reaction (ORR) around the air electrode lead to their poor energy efficiency. Herein, a novel bifunctional oxygen electrocatalyst is reported with the preparation of a zeolite imidazolate framework (ZIF-67) derived trimetallic composites decorated nitrogen-doped carbon, which consist of NiFe alloy and Co nanoparticles. The ZIF-derived porous N-doped carbon shell can speed up the mass transfer efficiency. Whereas the electronic effect between the formed NiFe alloy and Co nanoparticles, as well as the N-doped carbon framework can enrich the active centers and enhance the electrical conductivity. As a result, the NiFe-Co@NC-450 catalyst shows superior performance manifested as a small potential gap (Delta E = 0.857 V) between the overpotential at 10 mA cm(-2) (E (j=10)) for OER (460 mV) and half-wave potential (E (1/2)) for ORR (0.833 V). The liquid ZABs exhibit a high specific capacity reaching 798 mAh/g(Zn) and a stable cycling performance at 10 mA cm(-2) for more than 200 h. Meanwhile, the NiFe-Co@NC-450 based flexible ZABs also presents robust flexibility and stability. This study has certain implications for the development of economical, powerful and stable bifunctional catalysts for ZABs.

关键词： rechargeable zinc-air batteries bifunctional oxygen electrocatalysts oxygen reduction reaction oxygen evolution reaction trimetallic electrocatalyst

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The Analysis of Muscle-Synergy Similarity between Walking and Pedaling Based on Variational Mode Decomposition and Non-Negative Matrix Factorization 30

The Analysis of Muscle-Synergy Similarity between Walking an...

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30th IEEE International Conference on Engineering, Technology, and Innovation

作者： Ge, Wangyang She, Jinhua Guo, Shijie Wang, Feng Zhao, Juan Kawata, Seiichi China Univ Geosci Sch Automat Wuhan 430074 Peoples R China Hubei Key Lab Adv Control & Intelligent Automat C Wuhan 430074 Peoples R China Minist Educ Engn Res Ctr Intelligent Technol Geoexplorat Wuhan 430074 Peoples R China Tokyo Univ Technol Sch Engn Hachioji Tokyo 1920982 Japan Minist Educ Intelligent Rehabil Equipment & Detec Hebei Key Lab Robot Sensing & Human Robot Interac Engn Res Ctr Tianjin 300401 Peoples R China Hebei Univ Technol Sch Mech Engn Tianjin 300401 Peoples R China

ISBN: (纸本)9798350362442;9798350362435

Pedaling lower-limb rehabilitation robots are widely used in various stages of lower-limb rehabilitation because of their high safety and low requirements for patients' lower-limb strength. Researchers found that the activation sequence of the surface electromyographic (sEMG) signals of the muscles of the lower limb during pedaling is very similar to that of walking, which makes it possible to simulate the muscle force generation during walking by changing the pedal load during pedaling training. However, most pedaling lower-limb rehabilitation robots use constant loads, and it is of great importance to study the relationship between load and muscle synergy and to design load phase angle trajectories with higher muscle synergy consistency in the walking-pedaling motion to optimize the training effect of pedal-type rehabilitation robots. In this paper, we used variational mode decomposition (VMD) and non-negative matrix factorization (NMF) to extract the muscle synergy features in each band of sEMG during walking and pedaling and to study the similarity of pedaling and walking and the influence of pedal load on muscle synergy consistency.

关键词： muscle-synergy similarity sEMG signal variational mode decomposition non-negative matrix factorization

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