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Compound Pendulum Modeling and Resonant Frequency Analysis of the Lower Limbs for the Wearer and Exoskeleton

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Journal of Bionic Engineering 2015年第3期12卷 372-381页

作者： Yunjie Miao feng gao Dalei pan State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong University Shanghai China

An innovative lower extremity exoskeleton with hybrid leg structures is proposed in this paper. The compound pendulum model is applied to analyze the swing motion during walking for the wearer and the exoskeleton respectively. The expression of the resonant period for the human lower limb is obtained and the optimum stride frequency, at which the energy expenditure for walking is the least, coincides with the stride frequency of strolling well. As for the exoskeleton, the relationship between the inertial parameters and the resonant period of the hybrid leg is established. To minimize the walking energy cost for the exoskeleton, the inertial parameter design must guarantee that the resonant period of the hybrid leg coincides with the actual stride period of the wearer. The resonant period of the hybrid leg is also influenced by the scissor angle which determines the distance between the hip and the ankle of the lower extremity exoskeleton （SJTU-EX） and can be adjusted to match different stride frequencies of various motions by the proper scissor angle planning.

关键词： compound pendulum exoskeleton inertial parameter stride frequency

Creep rate sensitivities of materials by a depth-sensing indentation technique

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Journal of University of Science and Technology Beijing 2006年第4期13卷 308-312页

作者： Yang gao Shengping Wen feng pan Laboratory of Advanced Materials Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

The strain rate sensitivity to creep of single crystal Cu（110）, metal tantalum, and 128°Y-X LiNbO3 piezoelectric single crystal were measured at room temperature by MTS Nanoindenter XP. Among the three kinds of materials studied, Cu showed the highest degree of resistance to creep-induced deformation, which is followed by Ta, while the LiNbO3 single crystal deformed more readily than the others. The values of the steady-state strain rate sensitivities determined by the indentation methods are in the range of 0.002-0.006, 0.02-0.06 and 0.02-0.03 for Cu, Ta, and LiNbO3, respectively. The mechanisms for the indentation-induced creeping behavior and the factors that influenced the creeping are discussed.

关键词： indentation creep strain rate sensitivity copper tantalum LiNbO3 piezoelectric single crystal

Physical layer security of underlay cognitive radio using maximal ratio combining

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Frontiers of Information Technology & Electronic Engineering 2016年第9期17卷 929-937页

作者： Hui ZHAO Dan-yang WANG Chao-qing TANG Ya-ping LIU gao-feng pan Ting-ting LI Yun-fei CHEN School of Electronic and Information Engineering Southwest University School of Electrical & Electronic Engineering Newcastle University School of Mathematics and Statistics Southwest University School of Engineering University of Warwick

We investigate the secrecy outage performance of maximal ratio combining(MRC) in cognitive radio networks over Rayleigh fading channels. In a single-input multiple-output wiretap system, we consider a secondary user(SU-TX) that transmits confidential messages to another secondary user(SU-RX) equipped with M(M ≥ 1)antennas where the MRC technique is adopted to improve its received signal-to-noise ratio. Meanwhile, an eavesdropper equipped with N(N ≥ 1) antennas adopts the MRC scheme to overhear the information between SU-TX and SU-RX. SU-TX adopts the underlay strategy to guarantee the service quality of the primary user without spectrum sensing. We derive the closed-form expressions for an exact and asymptotic secrecy outage probability.

关键词： Cognitive radio networks Maximal ratio combining Secrecy outage probability Single-input multiple-output

Progranulin:A promising biomarker and therapeutic target for fibrotic diseases

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Acta Pharmaceutica Sinica B 2024年第8期14卷 3312-3326页

作者： Fan Yang Ming-Han Cheng Hai-feng pan Jian gao Pediatric Translational Medicine Institute Shanghai Children’s Medical CenterSchool of MedicineShanghai Jiao Tong UniversityShanghai 200000China Department of Ophthalmology the First Affiliated Hospital of Anhui Medical UniversityHefei 230022China Department of Epidemiology and Biostatistics School of Public HealthAnhui Medical UniversityHefei 230022China Inflammation and Immune Mediated Diseases Laboratory of Anhui Province Hefei 230022China

Progranulin(PGRN),a multifunctional growth factor-like protein expressed by a variety of cell types,serves an important function in the physiologic and pathologic processes of fibrotic diseases,including wound healing and the inflammatory *** was discovered to inhibit proinflammation effect by competing with tumor necrosis factor-alpha(TNF-a)binding to TNF ***,excessive tissue repair in the development of inflammation causes tissue *** investigations have indicated the significance of PGRN in regulating inflammatory ***,multiple studies have shown that PGRN was linked to fibrogenesis,and was considered to monitor the formation of fibrosis in multiple organs,including liver,cardiovascular,lung and *** paper is a comprehensive review summarizing our current knowledge of PGRN,from its discovery to the role in *** is followed by an in-depth look at the characteristics of PGRN,consisting of its structure,basic function and intracellular ***,we will discuss the potential of PGRN in the diagnosis and treatment of fibrosis.

关键词： Progranulin Fibrotic disease Fibrosis Inflammation Biomarker Therapeutic target PGRN/TNFR interaction Signaling pathway

Secrecy outage performance for wireless-powered relaying systems with nonlinear energy harvesters

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Frontiers of Information Technology & Electronic Engineering 2017年第2期18卷 246-252页

作者： Ji-liang ZHANG gao-feng pan Yi-yuan XIE Electronic and Information Engineering Southwest University Chongqing 300715 China

We consider a cooperative system consisting of a source node, a destination node, N （N 〉 1） wirelesspowered relays, and an eavesdropper. Each relay is assumed to be with a nonlinear energy harvester, in which there exists a saturation threshold, limiting the level of the harvested power. For decode-and-forward and power splitting protocols, the Kth best relay is selected to assist the source-relay-destination transmission. An analytical expression for the secrecy outage probability is derived, and also verified by simulation.

关键词： Decode-and-forward Energy harvesting Nonlinear Secrecy outage probability

Ergodic secrecy capacity of MRC/SC in single-input multiple-output wiretap systems with imperfect channel state information

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Frontiers of Information Technology & Electronic Engineering 2017年第4期18卷 578-590页

作者： Hui ZHAO You-yu TAN gao-feng pan Yun-fei CHEN School of Electronic and Information Engineering Southwest University Chongqing 400715 China School of Information Science and Technology ShanghaiTech University Shanghai 200120 China School of Engineering University of Warwick Coventry CV4 7AL UK

This paper investigates the secrecy performance of maximal ratio combining （MRC） and selection combining （SC） with imperfect channel state information （CSI） in the physical layer. In a single-input multiple- output （SIMO） wiretap channel, a source transmits confidential messages to the destination equipped with M antennas using the MRC/SC scheme to process the received multiple signals. An eavesdropper equipped with N antennas also adopts the MRC/SC scheme to promote successful eavesdropping. We derive the exact and asymptotic closed-form expressions for the ergodic secrecy capacity （ESC） in two cases：（1） MRC with weighting errors, and （2） SC with outdated CSI. Moreover, two important indicators, namely high signal-to-noise ratio （SNR） slope and high SNR power offset, which govern ESC at the high SNR region, are derived. Finally, simulations are conducted to validate the accuracy of our proposed analytical models. Results indicate that ESC rises with the increase of the number of antennas and the received SNR at the destination, and fades with the increase of those at the eavesdropper. Another finding is that the high SNR slope is constant, while the high SNR power offset is correlated with the number of antennas at both the destination and the eavesdropper.

关键词： Ergodic secrecy capacity (ESC) Mmximal ratio combining (MRC) Weighting errors Physical layer security Selection combining (SC) Single-input multiple-output (SIMO)

Flow Field Simulation and Parameter Analysis of Hydraulic Unbalanced Bionic Self-recovery Actuator for Rotary Equipment

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Journal of Bionic Engineering 2024年第1期21卷 325-343页

作者： Wei Li Xin pan Dehong Ge Jinji gao Key Laboratory of Engine Health Monitoring-Control and Networking of Ministry of Education Beijing University of Chemical TechnologyBeijing 100029China Beijing Key Laboratory of High-End Mechanical Equipment Health Monitoring and Self-Recovery Beijing University of Chemical TechnologyBeijing 100029China

The rotor is the most important component of rotating machinery,and the vibration produced by its mass unbalance has a serious influence on the secure and steady operation of the machine,so an effective online suppression technology is urgently needed.A new hydraulic unbalanced bionic self-recovery system is introduced,imitating the way of manually repairing faulty *** accomplish the effect of actuator mass redistribution,the technology employs pressurized air to drive the quantitative transfer of liquid in the reservoir cavity at opposite *** can complete the online adjustment of the equipment's balancing state and suppress the unbalanced vibration of equipment in real time,which gives the equipment the ability to maintain an autonomous health state and improve equipment *** composition and working principle of the system are introduced in detail,and the key performance parameters,such as the minimum running speed and the balancing liquid transfer speed,are analyzed *** fluid-solid coupling model of the actuator was established,and the two-phase flow from inside the hydraulic unbalanced bionic self-recovery actuator was simulated under multiple working conditions and the performance parameters were quantitatively analyzed.A balancing simulation test bed was built,and its effectiveness was verified by performance parameter tests and unbalanced bionic self-recovery *** experimental results show that the mass distribution adjustment of the balancing disk can be achieved using different viscosity balancing liquid,and the response of liquid viscosity 10 cSt is faster than that of liquid viscosity 100 cSt in the process of balancing liquid transfer,and the time is reduced by more than 75%;the system can reduce the simulated rotor amplitude from 18.3μm to 10.6μm online in real time,which provides technical support for the subsequent development of a new generation of bionic intelligent equipment.

关键词： Engineering self-recovery-Bionics Simulation analysis Self-recovery regulation

Intelligent ion gels: Design, performance, and applications

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SmartMat 2024年第1期5卷 38-58页

作者： Naiwei gao Caofeng pan Beijing Key Laboratory of Micro‐nano Energy and Sensor CAS Center for Excellence in NanoscienceBeijing Institute of Nanoenergy and NanosystemsChinese Academy of SciencesBeijingChina Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education Center for Stretchable Electronics and Nano SensorsCollege of Physics and Optoelectronic EngineeringShenzhen UniversityShenzhenChina School of Nanoscience and Engineering University of Chinese Academy of SciencesBeijingChina

Intelligent ion gels,which possess highly tunable mechanical,electrical,and stimulus‐responsive properties,have emerged as powerful candidates in the field of artificial intelligence,telemedicine,and health *** enrich the functionality of ion gels,it is critical to explore the link between the structure and function of ion *** this review,we provide an overview of the synthesis path and functional derivatives of ion *** conformational relationships of ion gels have been discussed,such as the effect of structure on electrical conductivity as well as sensing *** the perspective of stimulus response,the role of ion gels in areas such as bionic haptics,neural devices,artificial muscles,and intelligent displays has also been *** is possible that smart ion gels will open up a new horizon in the upcoming smart era,especially after the current challenges are resolved.

关键词： chemical structure intelligent electronics ion gels stimulus‐responsive

Unstructured Road Extraction in UAV Images based on Lightweight Model

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Chinese Journal of Mechanical Engineering 2024年第2期37卷 372-384页

作者： Di Zhang Qichao An Xiaoxue feng Ronghua Liu Jun Han feng pan School of Automation Beijing Institute of TechnologyBeijing 100081China Tianjin Institute of Maritime Navigation Instruments Tianjin 300130China The 716th Research Institute of China Shipbuilding Group Co. LtdJiangsu 222061China

There is no unified planning standard for unstructured roads,and the morphological structures of these roads are complex and *** is important to maintain a balance between accuracy and speed for unstructured road extraction *** road extraction algorithms based on deep learning have problems such as high model complexity,high computational cost,and the inability to adapt to current edge computing ***,it is best to use lightweight network *** the need for lightweight models and the characteristics of unstructured roads with different pattern shapes,such as blocks and strips,a TMB(Triple Multi-Block)feature extraction module is proposed,and the overall structure of the TMBNet network is *** TMB module was compared with SS-nbt,Non-bottleneck-1D,and other modules via *** feasibility and effectiveness of the TMB module design were proven through experiments and *** comparison experiment,using multiple convolution kernel categories,proved that the TMB module can improve the segmentation accuracy of the *** comparison with different semantic segmentation networks demonstrates that the TMBNet network has advantages in terms of unstructured road extraction.

关键词： Unstructured road Lightweight model Triple Multi-Block(TMB) Semantic segmentation net