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51篇 您的检索式:作者名="LIU Jinguo"
    题名 作者 年代 出处 被引量
1A human circulating immune cell landscape in aging and COVID-19显示文摘Age-associated changes in immune cells have been linked to an increased risk for infection.However,a global and detailed characterization of the changes that human circulating immune cells undergo with age is lacking.Here,we combined scRNA-seq,mass cytometry and sCATAC-seq to compare immune cell types in peripheral blood collected from young and old subjects and patients with COVID-19.We found that the immune cell landscape was reprogrammed with age and was characterized by T cell polarization from naive and memory cells to effector,cytotoxic,exhausted and reg-ulatory cells,along with increased late natural killer cells,age-associated B cells,inflammatory monocytes and age-associated dendritic cells.In addition,the expression of genes,which were implicated in coron-avirus susceptibility,was upregulated in a cell subtype-specific manner with age.Notably,COVID-19 promoted age-induced immune cell polarization and gene expression related to inflammation and cellular senes-cence.Therefore,these findings suggest that a dysreg-ulated immune system and increased gene expression associated with SARS-CoV-2 susceptibility may at least partially account for COVID-19 vulnerability in the elderly.Yingfeng Zheng Xiuxing Liu Wenqing Le Lihui Xie He Li Wen Wen Si Wang Shuai Ma Zhaohao Huang Jinguo Ye Wen Shi Yanxia Ye Zunpeng Liu Moshi Song Weiqi Zhang Jing-Dong J.Han Juan Carlos lzpisua Belmonte Chuanle Xiao Jing Qu Hongyang Wang Guang-Hui Liu Wenru Su 2020Protein & Cell2020,11,10:10
2Evaluation methods for the autonomy of unmanned systems显示文摘Future military and civilian unmanned systems will be extensively used on land,under the sea,in air,and in space.Evaluation of their autonomy is critical to realize the autonomous operation ability of unmanned systems.This paper discussed the basic concepts of autonomy and the significance of autonomy evaluation,and then surveys and describes existing evaluating methods.Based on analyses of key technologies and these technologies' technical readiness levels,a cobweb evaluation model as a universal evaluation model has been used to evaluate unmanned systems.If the technology warps(aspects of autonomy) and wefts(levels of those aspects) of unmanned systems can be determined for the cobweb model,the model can handle the mutual coupling,high dimensions,and diversity of warp lines.This model potentially has wide application in evaluating various unmanned systems.WANG YueChao Liu JinGuo 2012Chinese Science Bulletin2012,57,26:9
3Identification of the state-space model and payload mass parameter of a flexible space manipulator using a recursive subspace tracking method显示文摘The on-orbit parameter identification of a space structure can be used for the modification of a system dynamics model and controller coefficients. This study focuses on the estimation of a system state-space model for a two-link space manipulator in the procedure of capturing an unknown object, and a recursive tracking approach based on the recursive predictor-based subspace identification(RPBSID) algorithm is proposed to identify the manipulator payload mass parameter. Structural rigid motion and elastic vibration are separated, and the dynamics model of the space manipulator is linearized at an arbitrary working point(i.e., a certain manipulator configuration).The state-space model is determined by using the RPBSID algorithm and matrix transformation. In addition, utilizing the identified system state-space model, the manipulator payload mass parameter is estimated by extracting the corresponding block matrix. In numerical simulations, the presented parameter identification method is implemented and compared with the classical algebraic algorithm and the recursive least squares method for different payload masses and manipulator configurations. Numerical results illustrate that the system state-space model and payload mass parameter of the two-link flexible space manipulator are effectively identified by the recursive subspace tracking method.Zhiyu NI Jinguo LIU Zhigang WU Xinhui SHEN 2019Chinese Journal of Aeronautics2019,32,2:8
4ANALYSIS OF TIPOVER STABILITY FOR NOVEL SHAPE SHIFTING MODULAR ROBOT显示文摘一个新奇三模块的机器人被介绍了。适应不平的地面并且在稳定性上改进它的尖端能改变它的配置。这个 three-moduletracked 机器人有三种对称配置。他们是线类型,三角类型,和排类型。在因素和活动机器人在问题上的尖端的反措施被分析以后,在稳定性索引上的稳定性金字塔和尖端被建议到全球性确定的 mobilerobot 的静态的稳定性和动态稳定性。转移机器人的形状被这种技术在模拟在沥青的联合骚乱下面测试,滚动并且偏航。模拟结果证明这种技术为活动机器人在稳定性上的尖端的分析是有效的,特别为可计算的交换子或转移模块化的机器人的形状。三种对称配置的实验在未组织的环境下面被做。环境实验显示出象三角类型配置有的模拟的一样的结果最好的稳定性。模拟和实验为交换子提供有效引用可计算的机器人的潜在的应用程序。LIU Jinguo WANG Yuechao MA Shugen LI Bin 2006Chinese Journal of Mechanical Engineering2006,19,2:8
5Survey on research and development of on-orbit active debris removal methods显示文摘Space debris is growing dramatically with the rapid pace of human exploration of space,which seriously threatens the safety of artificial spacecraft in orbit.Therefore,the active debris removal(ADR)is important.This review aims to review the ADR methods and to advance related research in the future.The current research and development status are clearly demonstrated by mapping knowledge domain and charts.In this paper,the latest research results are classified and summarized in detail from two aspects of space debris capture and removal.The scheme comparison and evaluation of all ADR methods are performed,and the applicable scopes of various methods are summarized.Each ADR method is scored using a cobweb evaluation model based on six indicators.Future development of ADR is discussed to promote further research interest.ZHAO PengYuan LIU JinGuo WU ChenChen 2020Science China(Technological Sciences)2020,63,11:8
6Center-configuration selection technique for the reconfigurable modular robot显示文摘The reconfigurable modular robot has an enormous amount of configurations to adapt to various environments and tasks. It greatly increases the complexity of configuration research in that the possible configuration number of the recon-figurable modular robot grows exponentially with the increase of module number. Being the initial configuration or the basic configuration of the reconfigurable robot, the center-configuration plays a crucial role in system’s actual applications. In this paper, a novel center-configuration selection technique has been proposed for re-configurable modular robots. Based on the similarities between configurations’ transformation and graph theory, configuration network has been applied in the modeling and analyzing of these configurations. Configuration adjacency matrix, reconfirmation cost matrix, and center-configuration coefficient have been defined for the configuration network correspondingly. Being similar to the center-location problem, the center configuration has been selected according to the largest cen-ter-configuration coefficient. As an example of the reconfigurable robotic system, AMOEBA-I, a three-module reconfigurable robot with nine configurations which was developed in Shenyang Institute of Automation (SIA), Chinese Academy of Sciences (CAS), has been introduced briefly. According to the numerical simulation result, the center-configuration coefficients for these nine configurations have been calculated and compared to validate this technique. Lastly, a center- configu-ration selection example is provided with consideration of the adjacent configura-tions. The center-configuration selection technique proposed in this paper is also available to other reconfigurable modular robots.LIU JinGuo WANG YueChao LI Bin MA ShuGen TAN DaLong 2007Science in China(Series F)2007,50,5:7
7Novel Surface Design of Deployable Reflector Antenna Based on Polar Scissor Structures显示文摘Space-deployable mechanisms can be used as supporting structures for large-diameter antennas in space engineering.This study proposes a novel method for constructing the surface design of space reflector antennas based on polar scissor units.The concurrency and deployability equations of the space scissor unit with definite surface constraints are derived using the rod and vector methods.Constraint equations of the spatial transformation for space n-edge polar scissor units are summarized.A new closed-loop deployable structure,called the polar scissor deployable antenna(PSDA),is designed by combining planar polar scissor units with spatial polar scissor units.The overconstrained problem is solved by releasing the curve constraint that locates at the end-point of the planar scissor mechanism.Kinematics simulation and error analysis are performed.The results show that the PSDA can effectively fit the paraboloid of revolution.Finally,deployment experiments verify the validity and feasibility of the proposed design method,which provides a new idea for the construction of large space-reflector antennas.Pengyuan Zhao Jinguo Liu Chenchen Wu Yangmin Li Keli Chen 2020Chinese Journal of Mechanical Engineering2020,33,5:7
8Review of in-space assembly technologies显示文摘With the rapid development of space technology and the increasing demand for space missions,the traditional spacecraft manufacturing,deployment and launch methods have been unable to meet existing needs.In-space assembly(ISA)technologies can effectively adapt to the assembly of large space structures,improve spacecraft performance,and reduce operating costs.In this paper,the development and technologies for ISA are reviewed.ISA is classified from multiple angles,and the research status of ISA is shown clearly through the visual mapping knowledge domain.Then the development status of autonomous robot assembly in the United States,Europe,Japan,Canada and China is reviewed.Furthermore,the key technologies of ISA are analyzed from three aspects:assembly structure design,robot technologies and integrated management technologies.ISA technologies are still facing major challenges and need to be further explored to promote future development.Finally,future development trends and potential applications of ISA are given,which show that ISA will play a vital role in human space exploration in the future.Zhihui XUE Jinguo LIU Chenchen WU Yuchuang TONG 2021Chinese Journal of Aeronautics2021,34,11:6
9Network-based reconfiguration routes for a self-reconfigurable robot显示文摘This paper presents a network-based analysis approach for the reconfiguration problem of a self-reconfigurable robot. The self-reconfigurable modular robot named 'AMOEBA-I' has nine kinds of non-isomorphic configurations that consist of a configuration network. Each configuration of the robot is defined to be a node in the weighted and directed configuration network. The transformation from one configuration to another is represented by a directed path with nonnegative weight. Graph theory is applied in the reconfiguration analysis,where reconfiguration route,reconfigurable matrix and route matrix are defined according to the topological information of these configurations. Algorithms in graph theory have been used in enumerating the available reconfiguration routes and deciding the best reconfigu-ration route. Numerical analysis and experimental simulation results prove the va-lidity of the approach proposed in this paper. And it is potentially suitable for other self-reconfigurable robots' configuration control and reconfiguration planning.LIU JinGuo MA ShuGen WANG YueChao LI Bin 2008Science in China(Series F)2008,51,10:5
10Balancing flexural strength and porosity in DLP-3D printing Al_(2)O_(3)cores for hollow turbine blades显示文摘High porosity and high strength are usually mutually exclusive in the preparation of ceramic materials.However,high porosity and flexural strength are required for the preparation of complex ceramic cores for hollow turbine blades.In this study,Al_(2)O_(3)cores with high porosity and high flexural strength were successfully prepared using digital light processing(DLP)3 D printing technology.The influence of sintering temperature on the microstructure,pore evolution,and flexural strength of the cores were investigated.With an increase in the sintering temperature,the porosity of the ceramic cores first increased and then decreased,reaching a maximum value of 35%at 1400℃.The flexural strength increased with the increase in sintering temperature,but at 1400℃the incremental enhancement of flexural strength was greatest.Combined with the core service requirements and core performance,this study selected 1400℃(open porosity of 35.1%and flexural strength of 20.3 MPa)as the optimal sintering temperature for the DLP-3 D printed Al_(2)O_(3)core.Qiaolei Li Xiaolong An Jingjing Liang Yongsheng Liu Kehui Hu Zhigang Lu Xinyan Yue Jinguo Li Yizhou Zhou Xiaofeng Sun 2022Journal of Materials Science & Technology2022,,9:4
11Obstacle Avoidance and Multitarget Tracking of a Super Redundant Modular Manipulator Based on Bezier Curve and Particle Swarm Optimization显示文摘A super redundant serpentine manipulator has slender structure and multiple degrees of freedom.It can travel through narrow spaces and move in complex spaces.This manipulator is composed of many modules that can form different lengths of robot arms for different application sites.The increase in degrees of freedom causes the inverse kinematics of redundant manipulator to be typical and immensely increases the calculation load in the joint space.This paper presents an integrated optimization method to solve the path planning for obstacle avoidance and discrete trajectory tracking of a super redundant manipulator.In this integrated optimization,path planning is established on a Bezier curve,and particle swarm optimization is adopted to adjust the control points of the Bezier curve with the kinematic constraints of manipulator.A feasible obstacle avoidance path is obtained along with a discrete trajectory tracking by using a follow-the-leader strategy.The relative distance between each two discrete path points is limited to reduce the fitting error of the connecting rigid links to the smooth curve.Simulation results show that this integrated optimization method can rapidly search for the appropriate trajectory to guide the manipulator in obtaining the target while achieving obstacle avoidance and meeting joint constraints.The proposed algorithm is suitable for 3D space obstacle avoidance and multitarget path tracking.Li Chen Ying Ma Yu Zhang Jinguo Liu 2020Chinese Journal of Mechanical Engineering2020,33,5:4
12Behavior and adrenal activity in a group of zoo golden snub-nosed monkeys,Rhinopithecus roxellana,following social structure change显示文摘The effects of individual removal by zoo managers on behavior and fecal glucocorticoid changes in snub-nosed monkeys(Rhinopithecus roxellana) were investigated at Beijing Zoo.The results showed that the effect of the removal of three subordinate individuals(DD,male,4 years;XZZ,male,3 years and LL,female,3 years) from a group varied across the remaining group members that may be related to individual's social status,gender and age.The dominant male was impacted less than subordinate individuals in both the frequency and time duration for the four main behavioral categories.The frequency of stereotypic behavior significantly decreased in the dominant female after the removal of three animals(Z= 2.862,P=0.003).Fluctuations were found in both the behavioral frequency and time duration in other remaining individuals.These findings suggest that small,socially stable groups were somewhat resilient to changes in member composition.Moreover,the cortisol level did not change significantly in the remaining members.An alternative method of hormone assay using fecal samples for vulnerable animals was presented,and that may be useful for monitoring wild golden monkeys and other endangered species of animal.ZHANG XiaoLii HE Xini LIU DingZheni YAO XiuLini ZHANG YiZhuo ZHANG EnQuan ZHANG JinGuo JIANG GuoHua ZHAO ChangQi 2013Chinese Science Bulletin2013,58,17:4
13Effect of thermal exposure on the microstructure and creep properties of a fourth-generation Ni-based single crystal superalloy显示文摘The effect of thermal exposure on microstructure and creep properties of a fourth-generation nickelbased single crystal superalloy was investigated.The thermal exposure of samples after the full heat treatment was carried out at 1000℃,1100℃ and 1140℃ for 100 h and 200 h.The γ’ coarsening,γ’ rafting and γ channel widening were observed in samples after thermal exposure.When the thermal exposure time was constant,the morphology of γ’ phase in the alloy evolved significantly with increasing aging temperature.The interracial dislocation networks in aged samples after creep ruptured gradually became irregular and sparse with the increase of exposure temperature.When the higher exposure temperature was used,enla rgement of the defect pores was observed in samples,the microcracks were more likely to initiate and propagate at the corner of these pores.After aging at 1000℃ for 100 h,the creep life at 1140℃/137 MPa was slightly longer than that of heat-treated sample,which could be attributed to the slightly coarsened γ’ phase,homogenization of refractor elements.In contrast,the creep life of sample exposed at 1140℃ for 100 h was greatly decreased.The decrease of creep life was dominated by the rafting of γ’phase,the irregular interfacial dislocation networks as well as the enlargement of homogenization pores.Yeshun Huang Xinguang Wang Chuanyong Cui Zihao Tan Jinguo Li Yanhong Yang Jinlai Liu Yizhou Zhou Xiaofeng Sun 2021Journal of Materials Science & Technology2021,,10:4
14Epitaxial growth and oxidation behavior of an overlay coating on a Ni-base single-crystal superalloy by laser cladding显示文摘An overlay coating material was deposited on a single crystal superalloy SRR99 by laser cladding.The microstructure and oxidation behavior of this coating was investigated through scanning electron microscopy(SEM) and X-ray diffraction(XRD). The results indicated that although the composition of the coating was chosen based on the γ' composition in René N5 superalloy, the primary solidification phase of this coating during laser cladding was γ-Ni. Furthermore, under the laser cladding condition, fine parallel dendrites grew epitaxially in the coating from the substrate, indicating the single crystal structure of the substrate was reproduced. When the single crystal MCrAlY coating was oxidized at 1000?, both Al_2O_3 and Al_2O_3 formed during initial oxidation process. As the oxidation time proceeded, the presence of Al_2O_3 facilitated the formation of NiAl_2O_4 spinel oxide. Once the spinel was observed, it flourished and induced some porosity in the scale. When the scale thickness increased to 6–7 μm, large area spallation of the scale began.Jingjing Liang Yongsheng Liu Jinguo Li Yizhou Zhou Xiaofeng Sun 2019Journal of Materials Science & Technology2019,35,2:3
15Configuration analysis of a chain-type reconfigurable modular robot inspired by normal alkane显示文摘Normal alkane is an unbranched alkane whose structural formula is H–CH2–CH2–…–CH2–…–CH2–H,which can be regarded as a reconfigurable chain-type structure composed of–CH2–modules.Inspired by normal alkane,a normal-alkane-like reconfigurable modular robot (NAR) is proposed.The module consists of two differential gear trains mounted orthogonally.Each differential gear train contains two input degrees of freedom and two output degrees of freedom.Due to the genderless interface design,multiple modules can be assembled into chain-type configuration.With the genderless interfaces and flexible degrees of freedom,NAR can be reconfigured into different dimensions of spatial configuration.The bond matrix is used to describe the configuration,which represents the bond attitude of the adjacent connected modules.In addition,full interconnected geometric feature (FIGF) algorithm is proposed for non-isomorphic configuration enumeration and judgment.The configurations with three modules are simulated and the results verify the feasibility of the algorithm.Finally,a prototype with three modules is fabricated and the configuration motion sequence is demonstrated.FENG JingKai LIU JinGuo 2021Science China(Technological Sciences)2021,64,6:3
16Effects of Al on microstructural stability and related stress-rupture properties of a third-generation single crystal superalloy显示文摘To examine the influences of minor modification of Al content on the microstructural stabilities and stress rupture properties,two alloys with minor difference in Al content were exposed isothermally at 1100℃for 100 h,500 h,and 1000 h,respectively.The microstructures were characterized before and after thermal exposure.It was found that when Al content was decreased by 0.4 wt%,the volume fractionγ'decreased by 4%,the size ofγ'increased by 40 nm,the matrix channel width increased by 5 nm,and the misfit degree ofγ/γ'phases increased by 0.006%after heat treatment(HT).During thermal exposure,the alloy with low Al content had a better resistance to coarsening ofγ'phase and precipitation ofμphase.Theγ'particles of the alloy with high AI content tended to connect each other and coarsened along<100>directions;however,theγ'particles of the alloy with low Al content remained cubic after 500 h.A serious coarsening behavior took place in the two alloys after aging for 1000 h.The structural stabilities were significantly improved.However,the change of 0.4 wt%Al content was found to have little effect on the high temperature stress-rupture properties.Jingxia Sun Jinlai Liu Lirong Liu Yizhou Zhou Jinguo Lia Xiaofeng Sun 2019Journal of Materials Science & Technology2019,35,11:2
17Tool wear performance and surface integrity studies for milling DD5 Ni-based single crystal superalloy显示文摘Based on the results of slot milling experiments on the DD5 Ni-based single crystal superalloy(001) crystal plane along the [110]crystal direction, in this paper, efforts were devoted to investigate the tool wear process, wear mechanism and failure modes of the physical vapor deposition(PVD)-AlTiN and TiAlN coated tools under dry milling and water-based minimum quantity lubrication(MQL) conditions. The scanning electron microscope(SEM) morphological observation and energy dispersive X-ray spectroscopy(EDX) elements analysis methods were adopted. Moreover, under the water-based MQL condition, the surface integrity such as surface roughness, dimensional and shape accuracy, microhardness and microstructure alteration were researched. The results demonstrated that the tool edge severe adhesion with the work material, induced by the high Al content in the PVD-AlTiN coating caused the catastrophic tool tip fracture. In contrast, the PVD-TiAlN tool displayed a steady and uniform minor flank wear, even though the material peeling and slight chipping also occurred in the final stage. In addition, due to the high effective cooling and lubricating actions of the water-based MQL method, the PVD-TiAlN coated tool demonstrated intact tip geometry; consequently it could be repaired and reused even if the failure criterion was attained. Moreover, as the accumulative milling length and the tool wear increased, all indicators of the surface integrity forehand were deteriorated.GONG YaDong LI Qiang LI JinGuo LIU Yin SUN Yao 2018Science China(Technological Sciences)2018,61,4:2
18Special Issue on Reconfigurable Robots显示文摘Reconfigurable robots have the characteristics that structures can be changed or reorganized.They can adapt to different environments and tasks through changing configurations or structures,which is a hot research direction in recent years.Existing researches has not yet formed a complete theoretical method system of reconfigurable robots.Therefore,exploring new design theories,key technologies and typical applications is an effective way to promote the rapid development of this field.Jinguo Liu Yuwang Liu Guangbo Hao 2020Chinese Journal of Mechanical Engineering2020,33,5:2
19Microstructure evolution and mechanical behavior of Ni-based single crystal superalloy joint brazed with mixed powder at elevated temperature显示文摘Brazing of a Ni-based single crystal superalloy has been investigated with the additive Ni-based superalloy and filler Ni–Cr–W–B alloy at 1260℃, and attentions were paid to the microstructure evolution during brazing and the stress-rupture behavior at 980℃ of such brazed joints after homogenization. Microstructure in the brazed joint generally includes brazing alloy zone(BAZ), isothermally solidified zone(ISZ) and diffusion affected zone(DAZ). Microstructure evolution during this brazing process is discussed at the heating stage, the holding stage and the cooling stage respectively, according to the diffusion path of B atoms. Initially well-distributed γ’/γ’ microstructure in the homogenized bonded zone after heat treatment and substantial γ’ rafts enhance the post-brazed joint to obtain a stress-rupture lifetime of more than 120 h at 980℃/250 MPa. On the other hand, the decreased stress-rupture behavior of post-brazed joint, compared with parenting material, is ascribed to the presence of inside brazing porosity and stray grain boundary, which not only reduces the effective loading-carrying area but also offers preferential sites for creep vacancy aggregation to further soften stray grain boundary. And finally an early fracture of these post-brazed joints through the intergranular microholes aggregation and growth mode under this testing condition was observed.Guanglei Wang Yuan Sun Xinguang Wang Jide Liu Jinlai Liu Jinguo Li Jinjiang Yu Yizhou Zhou Tao Jin Xudong Sun Xiaofeng Sun 2017Journal of Materials Science & Technology2017,33,10:2
20Relationship between microstructures and contents of Ca/P in near-eutectic Al–Si piston alloys显示文摘Jinguo Qiao Xiangfa Liu Xiangjun Liu Xiufang Bian 2005Materials Letters2005,,14:2
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