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Real-Time Control Strategy of Exoskeleton Locomotion Trajectory Based on Multi-modal Fusion

Journal of Bionic Engineering 2023年第6期20卷 2670-2682页

作者： Tao Zhen lei yan College of Engineering Beijing Forestry UniversityNo.35East Qinghua RoadBeijing100083China

The exoskeleton robot is a typical man–machine integration system in the human *** ideal man–machine state is to achieve motion coordination,stable output,strong personalization,and reduce man–machine confrontation during *** order to achieve an ideal man–machine state,a Time-varying Adaptive Gait Trajectory Generator(TAGT)is designed to estimate the motion intention of the wearer and generate a personalized gait *** can enhance the hybrid intelligent decision-making ability under human–machine collaboration,promote good motion coordination between the exoskeleton and the wearer,and reduce metabolic *** important feature of this controller is that it utilizes a multi-layer control strategy to provide locomotion assistance to the wearer,while allowing the user to control the gait trajectory based on human–robot Interaction(HRI)force and locomotion *** this article,a Temporal Convolutional Gait Prediction(TCGP)model is designed to learn the personalized gait trajectory of the wearer,and the control performance of the model is further improved by fusing the predefined gait trajectory method with an adaptive interactive force control model.A human-in-the-loop control strategy is formed with the feedback information to stabilize the motion trajectory of the output joints and update the system state in real time based on the feedback from the inertial and interactive force *** experimental study employs able-bodied subjects wearing the exoskeleton for motion trajectory control to evaluate the performance of the proposed TAGT model in online *** from these evaluations demonstrate that the controller TAGT has good motor coordination and can satisfy the subject to control the motor within a certain range according to the walking habit,guaranteeing the stability of the closed-loop system.

关键词： Exoskeleton Multi-layer control strategy Human–machine collaboration Time-varying adaptive gait Hybrid intelligent

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Large eddy simulation study of 3D wind field in a complex mountainous area under different boundary conditions

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 541-556页

作者： yan LI lei yan Xuhui HE School of Civil Engineering Central South UniversityChangsha410075China National Engineering Research Center for High-speed Railway Construction Changsha410075China Hunan Provincial Key Laboratory for Disaster Prevention and Mitigation of Rail Transit Engineering Structures Changsha410075China

Large eddy simulations generally are used to predict 3D wind field characteristics in complex mountainous *** simulation boundary conditions,such as the height and length of the computational domain or the characteristics of inflow turbulence,can significantly impact the quality of *** this study,we examined these boundary conditions within the context of the mountainous terrain around a long-span cable-stayed bridge using a wind tunnel *** sizes of computational domains and turbulent incoming wind velocities were used in large eddy *** results show that when the height of the computational domain is five times greater than the height of the terrain model,there is minimal influence from the top wall on the wind field characteristics in this complex mountainous *** the length of the wake region of the computational domain has negligible effects on the wind *** in the inlet boundary reduces the length of the wake region on a leeward hill with a low slope,but has less impact on the mean wind velocity of steep hills.

关键词： Large eddy simulation(LES) Spectral representation method Recycling method High mountainous canyon Wind characteristics Atmospheric boundary layer Computational domain

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Ferrimagnetic Properties of Bond Dilution Mixed Blume-Capel Model with Random Single-Ion Anisotropy

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Communications in Theoretical Physics 2005年第4X期44卷 743-748页

作者： LIU lei yan Shi-lei Department of Physics Suzhou University Suzhou 215006 China Jiangsu Key Loboratory of Thin Films Suzhou University Suzhou 215006 China CCAST (World Loboratory) P.O. Box 8730 Beijing 100080 China

We study the ferrimagnetic properties of spin 1/2 and spin-1 systems by means of the effective field theory. The system is considered in the framework of bond dilution mixed Blume-Capel mode/ （BCM） with random single-ion anisotropy. The investigation of phase diagrams and magnetization curves indicates the existence of induced magnetic ordering and single or multi-compensation points. Special emphasis is placed on the influence of bond dilution and random single-ion anisotropy on normal or induced magnetic ordering states and single or multi-compensation points. Normal magnetic ordering states take on new phase diagrams with increasing randomness （bond and anisotropy）, while anisotropy induced magnetic ordering states are always occurrence no matter whether concentration of anisotropy is large or small. Existence and disappearance of compensation points rely strongly on bond dilution and random singleion anisotropy. Some results have not been revealed in previous papers and predicted by Néel theory of ferrimagnetism.

关键词： ferrimagnetic property mixed Blume-Capel model induced magnetic ordering compensation point bond dilution and random single-ion anisotropy

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Microwave-assisted in situ synthesis of fluorescent gold nanoclusters with BSA/montmorillonite and application on latent fingermark imaging

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Science China Chemistry 2018年第5期61卷 619-626页

作者： lei yan yanlin Yu Zhining Xia Forensic Science Engineering Research Center of Universities in Chongqing School of Criminal Investigation Southwest University of Political Science and Law School of Bioengineering Chongqing University

A method for in situ preparation of fluorescent gold nanoclusters(Au NCs) with bovine serum albumin/montmorillonite composite powder(Au NC-BSA/MMT) was developed, and the products were used to detect latent fingermarks. In this work, Au NCs were "grown" both inside and on the surface of BSA/MMT clay using one-step reduction of HAu Cl4 by BSA. The as-prepared Au NC-BSA/MMT nanocomposites emit intensive red fluorescence under the excitation of UV-visible light and show stable chemical features and low toxicity. The obtained fluorescent powders were characterized by UV-visible absorption spectroscopy,fluorescence spectroscopy, infrared spectroscopy, transmission electron microscopy/high-resolution transmission electron microscopy, scanning electron microscopy, X-ray photoelectron spectroscopy and X-ray diffraction to depict their sizes, structural information and optical features. Given their environmentally friendly preparation, simple operation, low cost, efficient UVvisible radiation-dependent photoluminescence and good affinity with finger residues, the in situ synthesized Au NC-BSA/MMT nanocomposite powders were used as an alternative fluorescent developing reagent for developing latent fingermarks deposited on various object surfaces(such as glass, aluminum foil, painted metal, plastic products and weighing papers) for individual identification. As results, the developed fingermarks with clear patterns and satisfactory level-2(minutiae points) and level-3(sweat pores) ridge details were obtained. Notably, treated prints could be excited by red light and emitted near infrared fluorescence, which was beneficial to avoid background interference and reduce the damage caused by UV light. With the advantages of the simple preparation process and good enhancement performance for latent fingermarks, the proposed method might be used in the preparation of various fluorescent probes for detecting trace evidence in forensic sciences.

关键词： gold nanoclusters in situ montmorillonite latent fingermark fluorescent powder forensic science

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Theoretical study of propene oxidation on Bi_2O_3 surfaces

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Science China Chemistry 2015年第4期58卷 593-600页

作者： yan-Hua lei Zhao-Xu Chen Key Laboratory of Mesoscopic Chemistry Ministry of Education Institute of Theoretical and Computational Chemistry School of Chemistry and Chemical Engineering Nanjing University

The role of bismuth in the selective oxidation of propene has long been debated. We performed density functional calculations to study the dehydrogenation reaction of propene on Bi203 surfaces. Our calculated thermodynamic data reveal that the first dehydrogenation of propene on the most stable （010） surface and the （100） surface are difficult. Our calculations indicate that the barrier of the first hydrogen abstraction on the high Miller index surface （211） is much lower than those on the （100） and （010） surfaces, and is close to the experimental one. Further dehydrogenation is shown to be difficult and production of 1,5-hexadiene through dimerization of allyl is likely, in agreement with the experimental observations.

关键词： hydrogen abstraction oxidation propene Bi2O3 surfaces reaction mechanism density functional theory

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Hyperspectral imaging technology to detect the vigor of thermal-damaged Quercus variabilis seeds

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Journal of Forestry Research 2021年第2期32卷 461-469页

作者： lei Pang Jiang Xiao Jingjing Ma lei yan School of Technology Beijing Forestry UniversityBeijing 100083People’s Republic of China

This study investigated the feasibility of hyperspectral imaging techniques to estimate the vigor of heatdamaged Quercus variabilis *** thermal damage grades were classified according to heat treatment duration(0,2,5,and 10 h).After obtaining hyperspectral images with a 370–1042 nm hyperspectral imager that included visible and near infrared light,germination was tested to confirm *** Savitzky–Golay(SG)second derivative was used to preprocess the spectrum to reduce any noise *** successive projections algorithm(SPA),principal component analysis,and local linear embedding algorithm were used to extract the characteristic spectral bands related to seed ***,a model for seed vigor classifi-cation of *** s based on partial least squares support vector machine(LS-SVM)with different spectral data sets was *** results show that the spectrum after SG second derivative preprocessing was better for developing the model,and SPA performed the best among the three feature band selection *** combination SG second derivative-LS-SVM provided the best classification model for *** seed vigor,with the prediction set reaching 98.81%.This study provides an important basis for rapid and nondestructive assessment of the vigor of heat-damaged seeds using hyperspectral imaging techniques.

关键词： Seed vigor level Quercus variabilis Heat damage Hyperspectral Least squares support vector machine

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Critical Properties of Mixed Ising Spin System with Different Trimodal Transverse Fields in the Presence of Single-Ion Anisotropy

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Communications in Theoretical Physics 2006年第6期45卷 1131-1136页

作者： CHEN Qiang yan Shi-lei Department of Physics Suzhou University Suzhou 215006 China Jiangsu Key Laboratory of Thin Films Suzhou University Suzhou 215006 China Nantong Shipping College Nantong 226006 China CCAST （World Loboratory） P.O. Box 8730 Beijing 100080 China

Within the framework of an effective field approximation, the effects of single-ion anisotropy and different trimodal transverse fields of two sublattices on the critical properties of the mixed spin-1/2 and spin-1 Ising system are investigated on the simple cubic lattice. A smaller single-lon anisotropy can magnify magnetic ordering phases and a larger one can depress magnetic ordering phase for T-Ω1/2 space at low temperatures, while a smaller single-ion anisotropy can hardly change the value of critical transverse field for T-Ω1 space. On the other hand, influences of two different trimodal transverse fields concentrations on tricritical points and magnetic ordering phases take on some interesting results in T-D space. The main reason comes from the common action of single-ion anisotropy, different transverse fields and two trimodal distributions.

关键词： critical property mixed spin system trimodal transverse field single-ion anisotropy

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Studies on the PEO-PPO-PEO Block Copolymer Release from Alginate Hydrogel

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Chemical Research in Chinese Universities 2001年第3期17卷 341-346页

作者： SU yan-lei GUO Chen LIU Hui-zhou Young Scientist Laboratory of Separation Science and Engineering State Key Laboratory of Biochemical EngineeringInstitute of Chemical MatellurgyChinese Academy of SciencesBeijing 100080P.R.China

Alginate hydrogel is one of the most widely used carriers for the immobilization of microbial cells. If surfactants are encapsulated with alginate hydrogel, increasing temperature or concentration can make the encapsu... 详细信息

关键词： Sodium alginate hydrogel PEO-PPO-PEO block copolymer Release mechanism

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Prescribed-Time Stabilization of Singularly Perturbed Systems

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IEEE/CAA Journal of Automatica Sinica 2023年第2期10卷 569-571页

作者： yan lei yan-Wu Wang Xiao-Kang Liu Wu yang the School of Artificial Intelligence and Automation Huazhong University of Science and Technology(HUST)Wuhan 430074 Key Laboratory of Image Processing and Intelligent Control Ministry of EducationWuhan 430074China the School of Electrical Engineering Guangxi UniversityNanning 530004China

Dear Editor, This letter investigates the prescribed-time stabilization of linear singularly perturbed systems. Due to the numerical issues caused by the small perturbation parameter, the off-the-shelf control design techniques for the prescribed-time stabilization of regular linear systems are typically not suitable here. To solve the problem, the decoupling transformation techniques for time-varying singularly perturbed systems are combined with linear time-varying high gain feedback design techniques.

关键词： prescribed stabilization perturbed

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CGI-100 Specific shRNA Inhibits Proliferation and Induces Differentiation in Leukemia K562 Cells

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Chinese Journal of Cancer Research 2010年第2期22卷 126-134页

作者： Yong-qiang Wang Ting-mei Chen yan lei Hong-lei Feng Ke Wang yan Zhang The Key Laboratory of Laboratory Medical Diagnostics of Ministry of Education Department of Clinical Biochemistry Chongqing Medical University Chongqing 400016 China

Objective： To investigate the characteristics of CGI-100- knockdown K562 cells and the effect of CGI-100 RNA interference （RNAi） on matrine-treated K562 cells. Methods： Three oligonucleotides targeting CGI-100 gene and a pair of negative control containing the same nucleotide composition with a different sequence were devised and chemically synthesized. The inhibition efficiency of CGI-100 expression by shRNA-CGI-100 in K562 cells was determined using semiquantitative RT-PCR and dot blot hybridization. The effect of CGI-100 RNAi on the growth of K562 cells was examined using MTT assay and cell differentiation was measured by distinct approaches including flow cytometry, benzidine staining and electron microscope. After CGI-100-konckdown K562 cells were incubated with 0.2 mg/ml of matrine or 30 Ixmol/L of hemin for 48 h, the expression levels of Glycophorin A（GPA）（CD235a） and Growth factor independence-lB mRNA（Gfi-IB mRNA） were measured by RT-PCR and the protein levels of GPA, CD14 and CD15 were detected by flow cytometry. Results： The eukaryotic expression vectors of CGI-100 RNAi were successfully constructed. The K562/shRNA-CGI-100 cell line was established in which the inhibition efficiency of CGI-100 gene expression by shRNA-CGI-100 was 54%. CGI-100-knockdown inhibited the proliferation and induced erythroid differentiation in K562 cells. Compared with the control K562 cells, the K562/shRNA-CGI-100 cells showed decreased absorbance value detected by MTT assay, decreased enchromation, increased heterochromation, increased percentage of G0/Gx phase cells, decreased population of S phase cells, decreased PI （proliferation index of cells）, and elevated percentage of benzidine-positive cells. Moreover, the sensitivity of K562/shRNA-CGI-100 cells to either matrine or hemin was enhanced and the sensitivity of these cells to matrine was higher than that to hemin. Compared with the control K562 cells, matrine treatment in K562/shRNA-CGI-100 cells resulted in increased i

关键词： CGI-100 RNA interference Leukemia Erythroid differentiation Matrine

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