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Acta Mechanica Sinica 2010年第2期26卷 279-288页

作者： lei jin Shijie Xu Department of Guidance Navigation and Control School of Astronautics Beihang University 100191 Beijing China

Angular velocity stabilization control and attitude stabilization control for an underactuated spacecraft using only two single gimbal control moment gyros （SGCMGs） as actuators is investigated. First of all, the dynamic model of the underactuated spacecraft is established and the singularity of different configurations with the two SGCMGs is analyzed. Under the assumption that the gimbal axes of the two SGCMGs are installed in any direction, and that the total system angular momentum is not zero, a state feedback control law via Lyapunov method is designed to globally asymptotically stabilize the angular velocity of spacecraft. Under the assumption that the gimbal axes of the two SGCMGs are coaxially installed along anyone of the three principal axes of spacecraft inertia, and that the total system angular momentum is zero, a discontinuous state feedback control law is designed to stabilize three-axis attitude of spacecraft with respect to the inertial frame. Furthermore, the singularity escape of SGCMGs for the above two control problems is also studied. Simulation results demonstrate the validity of the control laws.

关键词： Single gimbal control moment gyro ·Undcractuated spacecraft · Angular velocity stabilization · Three-axis attitude stabilization·Singularity

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客户端独立的IP地理定位研究综述

软件学报 2025年第1期36卷 321-340页

作者：林金磊李城龙宋光磊樊琳娜王之梁杨家海清华大学网络科学与网络空间研究院中关村实验室国防科技大学信息通信学院

准确、快速地获取IP地理定位信息对于各种网络应用而言至关重要. IP地理定位指将互联网实体的IP地址转换为其地理位置的技术.然而,互联网规模的迅速扩大和互联网应用的快速发展,给IP地理定位研究带来了巨大的挑战.首先,复杂的网络结构... 详细信息

准确、快速地获取IP地理定位信息对于各种网络应用而言至关重要. IP地理定位指将互联网实体的IP地址转换为其地理位置的技术.然而,互联网规模的迅速扩大和互联网应用的快速发展,给IP地理定位研究带来了巨大的挑战.首先,复杂的网络结构和网络环境导致IP定位技术的精确度远远无法满足实际的应用需求.其次,IP地理定位在各个领域的作用日益凸显,如何精准、高效、可靠地计算互联网主机的地理位置正在成为各行关注的焦点.因此,通过设备的IP地址对其进行地理定位以支撑复杂的上层应用尤为重要.自2001年以来,学术界和工业界围绕上述问题开展了大量的研究.系统地梳理客户端独立的IP地理定位方面的相关工作,系统地整理基于网络测量的IP地理定位研究分类方法.根据定位数据是否由主动测量产生,将相关研究分为主动的IP定位技术、被动的IP定位技术和主被动结合的IP定位技术.进一步,对每一类方法进行更细粒度的分类并分析其主要的优缺点.在此基础上,总结IP地理定位领域的最新进展和研究挑战,并展望其未来发展方向.

关键词：网络测量 IP地理定位地理定位地标

Local controllability and stabilization of spacecraft attitude by two single-gimbal control moment gyros

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Chinese Journal of Aeronautics 2013年第5期26卷 1218-1226页

作者： Gui Haichao jin lei Xu Shijie School of Astronautics Beihang University

The attitude control problem of a spacecraft underactuated by two single-gimbal control moment gyros （SGCMGs） is investigated. Small-time local controllability （STLC） of the attitude dynamics of the spacecraft-SGCMGs system is analyzed via nonlinear controllability theory. The conditions that guarantee STLC of the spacecraft attitude by two non-coaxial SGCMGs are obtained with the momentum of the SGCMGs as inputs, implying that the spacecraft attitude is STLC when the total angular momentum of the whole system is zero. Moreover, our results indi- cate that under the zero-momentum restriction, full attitude stabilization is possible for a spacecraft using two non-coaxial SGCMGs. For the case of two coaxial SGCMGs, the STLC property of the spacecraft cannot be determined. In this case, an improvement to the previous full attitude stabilizing control law, which requires zero-momentum presumption, is proposed to account for the singu- larity of SGCMGs and enhance the steady state performance. Numerical simulation results demonstrate the effectiveness and advantages of the new control law.

关键词： Attitude control Single-gimbal control moment gyro Singularity Small-time local controllability Underactuated spacecraft

Electronic structures and optic properties of Fe2TiO5 using LSDA+U approach

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Progress in Natural Science:Materials International 2013年第4期23卷 413-419页

作者： lei jin Chungen Zhou School of Materials Science and Engineering Beijing University of Aeronautics and Astronautics Key Laboratory of Aerospace Materials and Performance (Ministry of Education)

The magnetic properties,band structure,density of states(DOS) and optical properties of ferromagnetic Fe2TiO5were calculated by a plane wave pseudopotential method based on the local spin density approximation(LSDA) and the LSDA plus Hubbard U(LSDA+U) theory and compared with the known experimental and theoretical *** choosing the opportune Hubbard U parameter 4 eV,LSDA+U gives magnetic moments of 3.80 mB/Fe(3d orbital),which contribute the main magnetic moments to *** inclusion of U changes the band gap of Fe2TiO5and gives a value in better agreement with previous *** fnd that strong correlations dramatically change the density of states and band structures.A detailed analysis shows that the LSDA+U method provides the better description of electronic structures like this *** optical properties were explored *** is no ab-initio study related to Fe2TiO5at *** fndings provide good theoretical understanding for Fe2TiO5.

关键词： Fe2TiO5 Magnetic properties Electronic structures Optical properties LSDA+U

Influence of volute distortion on the performance of turbocharger centrifugal compressor with vane diffuser

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Science China(Technological Sciences) 2013年第11期56卷 2778-2786页

作者： ZHENG XinQian jin lei TAMAKI Hideaki State Key Laboratory of Automotive Safety and Energy Tsinghua University Turbo Machinery and Engine Technology Department IHI Corporation

As the geometry of the volute of turbocharger compressor is non-axisymmetric,it causes a distortion at the outlet of the diffuser and influences the upstream components.A distortion model in which a pressure distortion was applied as outlet boundary condition was established to simulate the distortion induced by the *** turned out to be sufficient to impose a circumferentially asymmetric pressure distribution at the outlet of the diffuser to replace the *** on the distortion model which was verified,the influence of the amplitude of the distortion on the performance of centrifugal compressor was studied in *** results show that the distortion severely harms aerodynamic stability of the investigated *** larger the amplitude of the distortion,the worse the performance of the *** distortion induced by asymmetric volute propagates to upstream components and causes local flow separation at part of diffuser and impeller,and then causes the compressor *** the amplitude of the volute distortion is 10%,the stable flow range of the centrifugal compressor decreases to near *** authors’knowledge,the relationship between the compressor performance and distortion amplitude is first obtained quantitatively,which provides evidence to improve the performance of turbocharger compressor by decreasing the distortion induced by asymmetric volute.

关键词： turbocharger vane diffuser centrifugal compressor stability distortion

Attitude control of a rigid spacecraft with one variable-speed control moment gyro

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Acta Mechanica Sinica 2013年第5期29卷 749-760页

作者： Hai-Chao Gui lei jin Shi-Jie Xu School of Astronautics Beihang University

Nonlinear controllability and attitude stabilization are studied for the underactuated nonholonomic dynamics of a rigid spacecraft with one variable-speed control moment gyro （VSCMG）, which supplies only two internal torques. Nonlinear controllability theory is used to show that the dynamics are locally controllable from the equilibrium point and thus can be asymptotically stabilized to the equilibrium point via time-invariant piecewise continuous feedback laws or time-periodic continuous feedback laws. Specifically, when the total angular momentum of the spacecraft-VSCMG system is zero, any orientation can be a controllable equilib- rium attitude. In this case, the attitude stabilization problem is addressed by designing a kinematic stabilizing law, which is implemented through a nonlinear proportional and deriva- tive controller, using the generalized dynamic inverse （GDI） method. The steady-state instability inherent in the GDI con- troller is elegantly avoided by appropriately choosing control gains. In order to obtain the command gimbal rate and wheel acceleration from control torques, a simple steering logic is constructed to accommodate the requirements of attitude sta- bilization and singularity avoidance of the VSCMG. Illustrative numerical examples verify the efficacy of the proposed control strategy.

关键词： Attitude control inverse Nonholonomic system Generalized dynamic Small-time local controlla- bility - Stabilization Variable-speed control moment gyro

Inverse Displacement Analysis of a Hyper-redundant Elephant＇s Trunk Robot

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Journal of Bionic Engineering 2018年第2期15卷 397-407页

作者： Yongjie Zhao lei jin Peng Zhang Jianyuan Li Department of Mechatronics Engineering Shantou University Shantou 515063 China

This paper deals with inverse displacement analysis of a Hyper-redundant Elephant＇s Trunk Robot （HRETR）. The HRETR is connected in series with n modules of 3UPS-PRU parallel mechanism where the underline P denotes an active prismatic joint. Based on the idea of differential geometry, backbone curve of the robot is formulated by using a parametric fimction consisting of sub-fimctions and control parameters. A general algorithm for generating a backbone curve and fitting the modules to the backbone curve is proposed. In this way, the inverse displacement analysis of the robot can be carried out by solving the inverse displacement problem of each parallel mechanism module and taking into account the length limits of the links. A HRETR with 6 modules is taken as an example to demonstrate the applicability of the algorithm.

关键词： inverse displacement analysis hyper-redundant bionic robot elephant's trunk robot 3UPS-PRU parallel mechanism backbone curve

A metal nitride interlayer for long life lithium sulfur batteries

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Journal of Energy Chemistry 2019年第2期28卷 1-2页

作者： jin-lei Qin Huiyou Zhao Jia-Qi Huang Department of Materials Science and Engineering China University of Mining and Technology (Beijing) Advanced Research Institute of Multidisciplinary Science Beijing Institute of Technology CAS Key Laboratory of Carbon Materials Institute of Coal ChemistryChinese Academy of Sciences

With the growing concerns on global energy crisis and the greenhouse effect,the exploration on renewable energy and related emerging energy conversion and storage technologies are highly interested [1].Lithium sulfur (Li–S) battery system receives great attention for its high theoretical specific energy(2600 Wh/kg),which is deemed to be a promising candidate as next generation high energy density batteries [2].

关键词： Shuttle of polysulfides Interlayers Layered double hydroxides Composite separators Lithium sulfur batteries

One-pot Three-component Mannich Reaction Catalyzed by 2-Hydroxylpyridine

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Chemical Research in Chinese Universities 2013年第4期29卷 710-713页

作者： jin Li-li lei Yun-tao College of Sciences China Pharmaceutical University Nanjing 210009 P. R. China

An effcient synthetic protocol for the β-amino carbonyl compounds was developed via one-pot three- component Mannich reaction of aromatic aldehydes, aromatic amines and cyclohexanone catalyzed by 2-hydroxylpy- ridine under mild reaction conditions, β-Amino carbonyl compounds were obtained in moderate to good yields and rea- sonable diastereoselectivities. The effects of different solvents, catalyst amounts and the scope of different substrates on the Mannich reactions were investigated. The plausible reaction mechanism was also discussed.

关键词： 2-Hydroxylpyridine Catalyze Mannich reaction fl-Amino carbonyl compound

Unselective ground-state blockade of Rydberg atoms for implementing quantum gates

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Frontiers of physics 2022年第2期17卷 33-45页

作者： jin-lei Wu Yan Wang jin-Xuan Han Shi-lei Su Yan Xia Yongyuan Jiang Jie Song School of Physics Harbin Institute of TechnologyHarbin 150001China School of Physics and Microelectronics Zhengzhou UniversityZhengzhou 450001China Department of Physics Fuzhou UniversityFuzhou 350002China

A dynamics regime of Rydberg atoms,unselective ground-state blockade(UGSB),is proposed in the context of Rydberg antiblockade(RAB),where the evolution of two atoms is suppressed when they populate in an identical ground *** is used to implement a SWAP gate in one step without individual addressing of *** at circumventing common issues in RAB-based gates including atomic decay,Doppler dephasing,and fluctuations in the interatomic coupling strength,we modify the RAB condition to achieve a dynamical SWAP gate whose robustness is much greater than that of the nonadiabatic holonomic one in the conventional RAB *** addition,on the basis of the proposed SWAP gates,we further investigate the implementation of a three-atom Fredkin gate by combining Rydberg blockade and *** present work may facilitate to implement the RAB-based gates of strongly coupled atoms in experiment.

关键词： Rydberg atoms unselective ground-state blockade SWAP gate Fredkin gate