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Flexible assistance strategy of lower limb rehabilitation exoskeleton based on admittance model

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Science China(Technological Sciences) 2024年第3期67卷 823-834页

作者： KOU JianGe WANG YiXuan CHEN ZhenLei shi Yan guo Qing XU Meng School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China School of Aeronautics and Astronautics University of Electronic Science and Technology of ChinaChengdu 611731China Department of Musculoskeletal Tumor Senior Department of Orthopedicsthe Fourth Medical Centerof PLA GeneralHospitalBeijing 100853China

Exercise training based on exoskeleton is an effective rehabilitation method for stroke patients. However, some rehabilitation exoskeletons still have poor wearable performance and obvious human-robot impedance during training, which easily cause secondary injuries to the patients. In this study, a variable admittance control strategy is proposed to improve the operator's wearable comfort, which can adapt to different operators by regulating admittance parameters. The admittance controller has two feedback loops: the position inner-loop and the admittance outer-loop. Meanwhile, the exoskeleton Lagrange model is constructed with unknown friction disturbance. By using Lyapunov technique and backstepping with state observer, the joint position error of exoskeleton is convergence into a zero neighborhood. The effectiveness of the proposed admittance controller is verified by both simulation and experiment. The tracking error of hip and knee joint is less than 4 degrees while the human-robot interaction torque is constrained in a tolerable range of the operator.

关键词： human-robot interaction exoskeleton backstepping admittance control

维普期刊数据库

Conversion of a single-layer ANN to photonic SNN for pattern recognition

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Science China(Information Sciences) 2024年第1期67卷 261-270页

作者： Yanan HAN Shuiying XIANG Tianrui ZHANG Yahui ZHANG Xingxing guo Yuechun shi State Key Laboratory of Integrated Service Networks State Key Discipline Laboratory of Wide Bandgap Semiconductor TechnologyXidian University Yongjiang Laboratory

This work presents a complete conversion scheme for photonic spiking neural networks(SNNs).We verified that the output of an artificial neural network(ANN) trained with the simulated optical activation function can be directly converted into the spike rate of a photonic spiking neuron *** reveal the feasibility of hardware implementation,we considered the effects of different bit precisions of data and weight,noise level,and bias current mismatch on the converted *** proposed scheme was evaluated using the Deterding vowel,IRIS,TIDIGITS,and MNIST datasets for pattern recognition,and achieved mean accuracies of 95.80%,98.67%,96.19%,and 92.33%,*** proposed scheme can convert an ANN into a photonic SNN with almost no precision loss,and the performance was comparable to that of an ANN trained with the rectified linear unit *** proposed scheme can enable the high-performance implementation of photonic SNNs.

关键词： photonic SNN conversion optical computing pattern recognition artificial neural network

Single-cell transcriptomic landscape of peripheral blood cells provides insights into adaptation of red-eared sliders(Trachemys scripta elegans)

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Integrative Zoology 2024年第3期19卷 468-479页

作者： Rui guo Guangwei MA Xiaofei ZHAI Haitao shi Jichao WANG Ministry of Education Key Laboratory for Ecology of Tropical Islands Key Laboratory of Tropical Animal and Plant Ecology of Hainan ProvinceCollege of Life SciencesHainan Normal UniversityHaikouChina

Red-eared sliders(Trachemys scripta elegans),as one of the 100 most threatening aliens,have stronger immunity than the native species in response to environmental *** cells are an important component of immunity in the ***,the blood cell researches of turtle are still in the traditional blood cell classification and morphological structure ***,turtle granulocytes cannot be accurately identified using traditional ***-cell RNA sequencing techniques have been successfully implemented to study cells based on the mRNA expression patterns of each *** present study profiled the transcriptomes of peripheral blood cells in red-eared sliders to construct a single-cell transcriptional landscape of the different cell types and explored environmental adaptation mechanism from the perspective of *** 14 transcriptionally distinct clusters(platelets,erythrocytes1,erythrocytes2,CSF1R monocytes,POF1B monocytes,neutrophils,GATA2high basophils,GATA2low basophils,CD4 T cells,CD7 T cells,B cells,ACKR4 cells,serotriflin cells,and ficolin cells)were identified in the peripheral blood cells of the red-eared *** particular,a subtype of erythrocytes(erythrocytes1)that expressed immune signals was *** blood cells were grouped into three lineages:platelet,erythroid/lymphoid,and myeloid cell ***,based on differentiation trajectory and up-regulated gene expression,ACKR4 cells were newly identified as lymphocytes,and serotriflin and ficolin cells as *** single-cell transcriptional atlas of the peripheral blood cells in red-eared sliders provided in the present study will offer a comprehensive transcriptome reference for the exploration of physiological and pathological hematology in this species.

关键词： blood cells single-cell RNA-seq Trachemys scripta elegans

Cracking on a nickel-based superalloy fabricated by direct energy deposition

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China Foundry 2024年第4期21卷 311-318页

作者： Xue Zhang Ya-hang Mu liang Ma Jing-jing liang Yi-zhou Zhou Xiao-feng Sun Jin-guo Li School of Materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

Cracks have consistently been a significant challenge limiting the development of additive manufactured nickel-based *** is essential to investigate the location of cracks and their forming *** study extensively examines the impact of solidification process,microstructural evolution,and stress concentration on crack initiation during direct energy deposition(DED).The results emphasize that the crack formation is significantly related to large-angle grain boundaries,rapid cooling *** caused by large-angle grain boundaries and a fast-cooling rate predominantly appear near the edge of the deposited *** cracks are more likely to form near the top of the deposited sample,due to the presence ofγ/γ'*** secondary dendritic arm and the carbides in the interdendritic regions can obstruct liquid flow during the final stage of solidification,which results in the formation of solidification cracks and *** work paves the way to avoid cracks in nickel-based superalloys fabricated by DED,thereby enhancing the performance of superalloys.

关键词： location cracks direct energy deposition nickel-based superalloys

维普期刊数据库

Pure quantum gradient descent algorithm and full quantum variational eigensolver

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Frontiers of physics 2024年第2期19卷 221-234页

作者： Ronghang Chen Zhou Guang Cong guo Guanru Feng shi-Yao Hou College of Physics and Electronic Engineering Center for Computational SciencesSichuan Normal UniversityChengdu 610068China Shenzhen SpinQ Technology Co. Ltd.Shenzhen 518045China DEEPROUTE.AI

Optimization problems are prevalent in various fields,and the gradient-based gradient descent algorithm is a widely adopted optimization ***,in classical computing,computing the numerical gradient for a function with variables necessitates at least d+1 function evaluations,resulting in a computational complexity of O(d).As the number of variables increases,the classical gradient estimation methods require substantial resources,ultimately surpassing the capabilities of classical ***,leveraging the principles of superposition and entanglement in quantum mechanics,quantum computers can achieve genuine parallel computing,leading to exponential acceleration over classical algorithms in some *** this paper,we propose a novel quantum-based gradient calculation method that requires only a single oracle calculation to obtain the numerical gradient result for a multivariate *** complexity of this algorithm is just O(1).Building upon this approach,we successfully implemented the quantum gradient descent algorithm and applied it to the variational quantum eigensolver(VQE),creating a pure quantum variational optimization *** with classical gradient-based optimization algorithm,this quantum optimization algorithm has remarkable complexity advantages,providing an efficient solution to optimization *** proposed quantum-based method shows promise in enhancing the performance of optimization algorithms,highlighting the potential of quantum computing in this field.

关键词： quantum algorithm gradient descent variational quantum algorithm

Deep learning for joint channel estimation and feedback in massive MIMO systems

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Digital Communications and Networks 2024年第1期10卷 83-93页

作者： Jiajia guo Tong Chen shi Jin Geoffrey Ye Li Xin Wang Xiaolin Hou National Mobile Communications Research Laboratory Southeast UniversityNanjing210096China Department of Electrical and Electronic Engineering Imperial College LondonLondonSW72AZUK DOCOMO Beijing Communications Laboratories Co. LtdBeijingChina

The great potentials of massive Multiple-Input Multiple-Output(MIMO)in Frequency Division Duplex(FDD)mode can be fully exploited when the downlink Channel State Information(CSI)is available at base ***,the accurate CsI is difficult to obtain due to the large amount of feedback overhead caused by massive *** this paper,we propose a deep learning based joint channel estimation and feedback framework,which comprehensively realizes the estimation,compression,and reconstruction of downlink channels in FDD massive MIMO *** networks are constructed to perform estimation and feedback explicitly and *** explicit network adopts a multi-Signal-to-Noise-Ratios(SNRs)technique to obtain a single trained channel estimation subnet that works well with different SNRs and employs a deep residual network to reconstruct the channels,while the implicit network directly compresses pilots and sends them back to reduce network *** module is also designed to generate data-bearing *** results show that the two proposed networks exhibit excellent performance of reconstruction and are robust to different environments and quantization errors.

关键词： Channel estimation CSI feedback Deep learning Massive MIMO FDD

Advances of high-performance LiNi_(1-x-y)Co_(x)M_(y)O_(2) cathode materials and their precursor particles via co-precipitation process

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Particuology 2024年第3期86卷 67-85页

作者： Wenbiao liang Yin Zhao Liyi shi Zhuyi Wang Yi Wang Meihong Zhang Shuai Yuan School of Materials Science and Engineering Shanghai UniversityShanghai200444China Research Center of Nanoscience and Nanotechnology Shanghai UniversityShanghai200444China Emerging Industries Institute Shanghai UniversityJiaxingZhejiang314006China

Layered LiNi_(1-x-y)Co_(x)M_(y)O_(2)(M=Mn or Al)is a promising cathode material for lithium-ion batteries due to its high specific capacity and acceptable manufacturing ***,the polycrystalline LiNi_(1-x-y)Co_(x)M_(y)O_(2) cathode material suffers from disordered orientation of primary particles and poor geometric symmetry of secondary particles,which severely hampers the migration of Lit ***,the resulting anisotropy accelerates the disintegration of the secondary particle structure,significantly affecting the electrochemical performance of the polycrystalline *** spite of less grain boundary,the single-crystal LiNi_(1-x-y)Co_(x)M_(y)O_(2) cathodes still suffer from severe microcracks generated by repeated planar gliding during cycling,which poses a great challenge to the cycling stability of single-crystal ***'s worth noting that the microstructure of the cathode material is mainly inherited from its ***,it is necessary to deeply understand the influence of the microstructure of Ni_(1-x-y)Co_(x)M_(y)(OH)2 on the electrochemical properties of LiNi_(1-x-y)Co_(x)M_(y)O_(2) cathode materials,so as to optimize the production process of preparing high-performance cathode *** this review,we summarize recent advances in the research and development of Ni-rich cathode precursor ***,the challenges faced by the Ni-rich hydroxide precursor materials are presented,including the effect of primary particle morphology and arrangement on the electrochemical performance of cathode materials,the influence of secondary particle morphology on lithium insertion reactions in cathode,and the effect of particle size on the microcracking of single-crystal ***,the presentation of the conventional co-precipitation reactor,the mechanism of precursor particle growth,and the influence of coprecipitation parameters are described in ***,the strategies are systematically discussed to solve the cha

关键词： Lithium-ion batteries Cathode materials Co-precipitation Ni-rich layered oxides Single crystal Precursor particles

Solvent extraction of scandium from leaching solution of red mud roasted with ammonium sulfate using D2EHPA/TBP

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Journal of Rare Earths 2024年第10期42卷 1943-1949页

作者： Fucheng Li Xinsheng Li Lei shi Xiang Li Duoqiang liang Yuezhou Wei Toyohisa Fujita School of Resources Environment and MaterialsGuangxi University State Key Laboratory of Featured Metal Materials and Life-cycle Safety for Composite Structures Guangxi University School of Nuclear Science and Technology University of South China

Red mud is an important secondary resource for scandium *** red mud leaching solution containing scandium in this study was derived from environmentally friendly ammonium sulfate roasting and water leaching process.A synergistic extraction with a mixture of di（2-ethylhexyl） phosphate acid（D2EHPA） and tributyl phosphate（TBP） for recovery of scandium from red mud leaching solution is *** effects of D2EHPA concentration,H2SO4concentration,rare earth elements,dosage of TBP,phase ratio（A/O）,contact time and H2O2concentration on scandium extraction were *** results show that more than 99% scandium is extracted under the optimal conditions while Fe,Al,Ti,Ca and rare earth elements（Ce,Y,La,Nd,Er,etc.） are hardly *** stripping efficiency of Sc reaches above 92.37% under the optimal stripping conditions of 5 mol/L NaOH with an A/O of 1 at 90℃ for 30 *** proposed technology could provide an effective method for extraction of scandium from red mud leaching solution.

关键词： D2EHPA/TBP Rare earths Red mud leaching solution Scandium Solvent extraction

Research on Gait Trajectory Planning of Wall-Climbing Robot Based on Improved PSO Algorithm

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Journal of Bionic Engineering 2024年第4期21卷 1747-1760页

作者： Jian Li Xianlin shi Peng liang Yanjun Li Yilin Lv Mingyue Zhong Zezhong Han School of Mechanical and Automotive Engineering Guangxi University of Science and TechnologyLiuzhou545006China

In order to reduce the labor intensity of high-altitude workers and realize the cleaning and maintenance of high-rise building exteriors,this paper proposes a design for a 4-DOF bipedal wall-climbing bionic robot inspired by the inchworm’s *** robot utilizes vacuum adsorption for vertical wall attachment and legged movement for *** enhance the robot’s movement efficiency and reduce wear on the adsorption device,a gait mimicking an inchworm’s movement is planned,and foot trajectory planning is performed using a quintic polynomial *** velocity constraints,foot trajectory optimization is achieved using an improved Particle Swarm Optimization(PSO)algorithm,determining the quintic polynomial function with the best fitness through ***,through comparative experiments,the climbing time of the robot closely matches the simulation results,validating the trajectory planning method’s accuracy.

关键词： Bionic robot Wall-climbing robot PSO Gait planning Trajectory planning