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Dynamics Analysis of a Parallel Mill-turn Tool Spindle Head Driven by Dual-linear Motors Using Extended Transfer Matrix Method

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Chinese Journal of Mechanical Engineering 2011年第5期24卷 859-869页

作者： wu wenjing liu qiang School of Mechanical Engineering and Automation Beihang University Beijing 100191

The hybrid dynamics of multi-rigid-body and multi-flexible-body system becomes the mainstream of multi-body *** there lacks a compact approach to model the hybrid dynamics,especially in modern machine tool application,due to the difficulty of solving the hybrid equations or the limitation of current software when dealing with the hybrid *** extended transfer matrix method（E-TMM）,which extends elements in three-dimensional space with higher matrixes,is proposed to simplify the modeling process of the hybrid *** E-TMM modeling approaches of 3 basic elements including 3D vibrant rigid body,joint and flexible body are studied in details.A parallel mill-turn tool spindle head unit driven by dual-linear motors is chosen as a plant to demonstrate the E-TMM modeling *** using E-TMM,the spindle head unit is simplified as a topological network consisting of the three types of element,i.e.,3D vibrant rigid body,joint and flexible body,including 11 rigid bodies,14 joints and 1 3D-Timoshenko *** the dynamic model of the system can be easily obtained by deducing the element-network by means of state vector *** dynamic characteristics of the spindle head,such as natural frequencies,dynamic flexibility,*** be predicted by solving the obtained *** verification indicates that the E-TMM is valid with enough accuracy in the dynamic analysis of the parallel mill-turn tool spindle *** E-TMM is capable of modeling the dynamics of machine tool structure with no requirements of deducing and solving the sophisticated differential ***,the E-TMM provides a simple and elegant tool for hybrid dynamic analysis in future dynamic design of machine tools.

关键词： NC machine tools dynamics modeling transfer matrix method(TMM)

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Deciphering fungal metabolon coupling tandem inverse-electrondemand Diels-Alder reaction and semipinacol rearrangement for the biosynthesis of spiro polycyclic alkaloids

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Science China Chemistry 2025年第01期 288-296页

作者： Shuai liu Wen-qiang Xu Ying-Tong Di Man-Cheng Tang Ding-Kang Chen Ming-Ming Cao Yao-Wen Chang Hong-Yu Tang Chun-Mao Yuan Jun-Bo Yang Zhi-Li Zuo Han Guo Zi-Fei Xu Ying Zeng Yun-Dong wu Xiao-Jiang Hao Key Laboratory of Phytochemistry and Natural Medicines (Chinese Academy of Sciences) Kunming Institute of Botany Chinese Academy of Sciences University of Chinese Academy of Sciences Lab of Computational Chemistry and Drug Design State Key Laboratory of Chemical Oncogenomics Peking University Shenzhen Graduate School Shenzhen Bay Laboratory State Key Laboratory of Microbial Metabolism School of Life Sciences & Biotechnology Shanghai Jiao Tong University State Key Laboratory of Functions and Applications of Medicinal Plants Guizhou Medical University Molecular Biology Experimental Center Germplasm Bank of Wild Species in Southwest China Kunming Institute of Botany Chinese Academy of Sciences Yunnan Key Laboratory for Wild Plant Resources Kunming Institute of Botany Chinese Academy of Sciences Research Unit of Chemical Biology of Natural Anti-Virus Products Chinese Academy of Medical Sciences

In the intricate process of natural product biosynthesis, a metabolon can enhance metabolic flux by associating sequential enzymes. A fungal metabolon, comprising of flavin-dependent monooxygenase Spe F and P450 monooxygenase Spe G, is identified in the biosynthesis of spiro polycyclic alkaloids(+)-notoamide B and its diastereomer(+)-versicolamide B. Using notoamide E as a substance, Spe F/Spe G metabolon can control the stereoselectivity of its 2,3-epoxidation, followed by hydrogen atom ion at C-17 to generate reactive epoxide tau-m A with dienyl iminium unit. Subsequently,(+)-notoamide B and(+)-versicolamide B are produced via tandem nonenzymatic inverse-electron-demand Diels-Alder reaction and semipinacol rearrangement. This provides the first example of metabolon in the biosynthesis of spiro-prenylated indole alkaloids.

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Recent advances in visible-light-driven organic reactions

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National Science Review 2017年第3期4卷 359-380页

作者： qiang liu Li-Zhu wu State Key Laboratory of Applied Organic Chemistry Lanzhou University Key Laboratory of Photochemical Conversion and Optoelectronic Materials Technical Institute of Physics and ChemistryChinese Academy of Sciences

In recent years, visible-light-driven organic reactions have been experiencing a significant renaissance in response to topical interest in environmentally friendly green chemical synthesis. The transformations using inexpensive, readily available visible-light sources have come to the forefront in organic chemistry as a powerful strategy for the activation of small molecules. In this review, we focus on recent advances in the development of visible-light-driven organic reactions, including aerobic oxidation, hydrogen-evolution reactions, energy-transfer reactions and asymmetric reactions. These key research topics represent a promising strategy towards the development of practical, scalable industrial processes with great environmental benefits.

关键词： visible light catalysis synthesis photocatalyst aerobic oxidation hydrogen evolution energy transfer asymmetric photoreaction

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WiFi CSI Gesture Recognition Based on Parallel LSTM-FCN Deep Space-Time Neural Network

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China Communications 2021年第3期18卷 205-215页

作者： Zhiling Tang Qianqian liu Minjie wu wenjing Chen Jingwen Huang Guangxi Key Laboratory of Wireless Broadband Communication and Signal Processing Guilin University of Electronic TechnologyGuilin 541004China

In this study,we developed a system based on deep space–time neural networks for gesture *** users change or the number of gesture categories increases,the accuracy of gesture recognition decreases considerably because most gesture recognition systems cannot accommodate both user differentiation and gesture *** overcome the limitations of existing methods,we designed a onedimensional parallel long short-term memory–fully convolutional network(LSTM–FCN)model to extract gesture features of different *** can learn complex time dynamic information,whereas FCN can predict gestures efficiently by extracting the deep,abstract features of gestures in the spatial *** the experiment,50 types of gestures of five users were collected and *** experimental results demonstrate the effectiveness of this system and robustness to various gestures and individual *** analysis of the recognition results indicated that an average accuracy of approximately 98.9% was achieved.

关键词： signal and information processing parallel LSTM-FCN neural network deep learning gesture recognition wireless channel state information

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Brain Cognition Mechanism-Inspired Hierarchical Navigation Method for Mobile Robots

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Journal of Bionic Engineering 2024年第2期21卷 852-865页

作者： qiang Zou Chengdong wu Ming Cong Dong liu Faculty of Robot Science and Engineering Northeastern UniversityShenyang110819China School of Mechanical Engineering Dalian University of TechnologyDalian116024China

Autonomous navigation is a fundamental problem in *** methods generally build point cloud map or dense feature map in perceptual space;due to lack of cognition and memory formation mechanism,traditional methods exist poor robustness and low cognitive *** a new navigation technology that draws inspiration from mammal’s navigation,bionic navigation method can map perceptual information into cognitive space,and have strong autonomy and environment *** improve the robot’s autonomous navigation ability,this paper proposes a cognitive map-based hierarchical navigation ***,the mammals’navigation-related grid cells and head direction cells are modeled to provide the robots with location *** then a global path planning strategy based on cognitive map is proposed,which can anticipate one preferred global path to the target with high efficiency and short ***,a hierarchical motion controlling method is proposed,with which the target navigation can be divided into several sub-target navigation,and the mobile robot can reach to these sub-targets with high confidence ***,some experiments are implemented,the results show that the proposed path planning method can avoid passing through obstacles and obtain one preferred global path to the target with high efficiency,and the time cost does not increase extremely with the increase of experience nodes *** motion controlling results show that the mobile robot can arrive at the target successfully only depending on its self-motion information,which is an effective attempt and reflects strong bionic properties.

关键词： Bionic navigation Spatial localization cells Global path planning Hierarchical motion controlling

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Inversion of the asymmetry factor for desert areas of China

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Science China Earth Sciences 2010年第4期53卷 561-567页

作者： wu YunZhao LU HuaYu liu qiang School of Geographic and Oceanographic Sciences Nanjing UniversityNanjing 210093China Institute of Remote Sensing Applications Chinese Academy of SciencesBeijing 100101China

Deserts,which have high surface albedo and wide area,are important components of the earth *** is very important for the research of surface radiation and energy balance to understand the anisotropic scattering of desert *** emergence and development of multi-angle remote sensing made possible the inversion of the anisotropic scattering of desert areas at the regional or global ***,this paper explored the accuracy of the inversion of asymmetry factor using the Hapke model and the simulated single-and multi-phase MISR *** on the results,the asymmetry factor of representative surface of desert areas in northwestern China was *** values of the asymmetry factor retrieved from MISR data were compared with the values retrieved from the laboratory *** results showed that the single-phase MISR data could be used for the inversion of asymmetry parameter of desert *** sign of the asymmetry parameter for the laboratory measurements was positive,which suggests that the surface of laboratory samples is forward *** sign of the asymmetry parameter for MISR data was negative;that is,it is *** values of the asymmetry parameters retrieved from MISR data were related to the character of the land *** Loulan,where the surface was smoother than other sites,retrieved values exhibited the largest negative values of asymmetry factor,suggesting the strongest *** sand dune area of the Kumtag Desert,which has the greatest roughness,had only slightly negative asymmetry factor *** findings indicated that at the sensor scale,a rough surface(e.g.,dunes) does not necessarily mean more backscattering than a smooth *** finding has significant implications for empirical methods(e.g.,using the normalized index of backward-scattered radiance minus forward-scattered radiance as an indicator of surface roughness),which should be used carefully for analyzing surface roughness from the remote

关键词： MISR Hapke model asymmetry parameter inversion Kumtag Desert multi-angle remote sensing

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Noncollinear Interaction of Guided Optical Waves and Magnetostatic Forward Volume Waves Under Inclined Bias Magnetic Field

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Chinese Physics Letters 1999年第4期16卷 288-289页

作者： wu Bao-jian liu Gong-qiang Department of Applied Physics Shanghai Jiaotong UniversityShanghai 200240

Coupled-mode equations for Stokes and anti-Stokes interactions of guided optical waves with magnetostatic forward volume waves under inclined magnetic field are *** results indicate that,only at normal magnetization,the diffraction efficiency(DE)is equal to the mode-conversion efficiency(MCE)in magnitude;by comparison to the case of normal magnetization,the DE and the MCE can be increased greatly under appropriate inclined magnetic *** the YIG waveguide used,the DE for the Stokes interaction is much greater than that for the anti-Stokes interaction when the inclined angle|θ|<25o and the MCE is symmetrical aboutθ.For the Bi-doped YIG film,the MCE presents a rapid oscillation withθ.The obtained results tally with the experiments.

关键词： field. magnetization oscillation

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Influence of isothermal bainitic processing on the mechanical properties and microstructure characterization of TRIP steel

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Journal of University of Science and Technology Beijing 2008年第5期15卷 574-579页

作者： Haitao Jiang Hubin wu Di Tang qiang liu National Engineering Research Center for Advanced Rolling Technology University of Science and Technology Beijing Beijing 100083 China

The mechanical properties of transformation induced plasticity （TRIP） steel are strongly affected by the conditions of iso-thermal bainitic processing. The multiphase microstructure of TRIP steel under different conditions of isothermal bainitic processing was investigated using OM,SEM,XRD and TEM. The volume fraction of retained austenite and the carbon content in austenite were determined quantitatively using X-ray diffraction patterns. The relationship between mechanical properties and isothermal bainitic processing parameters was investigated. The stability of retained austenite was analyzed by the volume fraction of retained austenite and the carbon content in retained austenite. The experimental results show that the multiphase microstructure consists of ferrite,bainite and metastable retained *** obtain good mechanical properties,the optimal conditions of isothermal bainitic temperature and holding time are 410-430°C and 180-240 s,respectively. After isothermal bainitic processing under the optimal conditions,the corresponding volume fraction of retained austenite is 5vol%-15vol%,which can provide enough retained austenite and plastic stability for austenite with high carbon content.

关键词： transformation induced plasticity steel isothermal bainitic processing mechanical properties microstructure

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EXPERIMENTAL STUDY OF 3-D TURBULENT BEND FLOWS IN OPEN CHANNEL

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Journal of Hydrodynamics 2005年第6期17卷 704-712页

作者： liu Yue-qin ZHENG Shao-wen wu qiang School of Resource and Safety Engineering China University of Mining and Technology. Beijing 10083China College of Traffic and Communications South China University of Technology Guangzhou 510640 China

A generalized hend flow model, treating a 90° single bend and 60° continuous hends, was designed to quantitatively describe 3-D turhulenee mechanism of circulating notfully-developed flow in open channels with hends. The 3-D fluctuating veloeities of turbulent flow were measured and analyzed with a 3 D acoustic-Doppler velocimeter. Formula for 3 D turbulent intensity was derived using the dimension analysis approaeh. Expressions of vertical turbulent intensity distributions were obtained with the multivariant-rcgression theo ry, whieh agree with experiment data. Distrihutions of turbulent intensity and turbulent stress were characterized, and their relationships were concluded. In the bend-turbulent flow core region, longitudinal and lateral turbulent-intensity distri hutions are coincident with linear distribution, hut in nearwall region are coincident with the Gamma distribution. Verotical turbulent intensity distributions are coincident with the Rayleigh distribution. Herein, it is concluded that the bend turbulence is anisotropic.

关键词： Reynolds stress 3-D turbulent intensity,bend flow channel model

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Mode Conversion and Diffraction of Guided Optical Waves from Magnetostatic Waves under Inclined Bias Magnetic Field

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Communications in Theoretical Physics 2001年第10期36卷 497-502页

作者： wu Bao-Jian liu Gong-qiang ZOU Zhi-qiang Department of Applied Physics Shanghai Jiao Tong University Shanghai 200030 China Department of Applied Physics Shanghai Jiao Tong University Shanghai 200030 China Department of Applied Physics Shanghai Jiao Tong University Shanghai 200030 China

The noncollinear interaction of guided optical waves with magnetostatic waves under inclined bias magnetic field is theoretically studied in detail. Similar approach can also be applied to the collinear interaction. Calculation results indicate that the diffraction efficiency (DE) in magnitude is equal to the mode-conversion efficiency (MCE) under vertical bias magnetic field, but they differ greatly under inclined bias magnetic field. By comparison to the case of vertical magnetization, the DE or the MCE can be greatly increased under inclined magnetic field. The characteristic of the DE curves obtained is basically in agreement with the experimental result.

关键词： guided optical wave, magnetostatic wave, mode conversion, diffraction efficiency

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