检索结果-内蒙古大学图书馆

Experimental and numerical flutter analysis of a folding fin with multiple asymmetric free-plays

Chinese Journal of Aeronautics 2024年第5期37卷 332-348页

作者： Chenyu LIU Chao AN Changchuan XIE Xin ZHANG Lan YANG School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China Beijing Institute of Electronic System Engineering Beijing 100854China Beijing Institute of Astronautical Systems Engineering Beijing 100076China

Experimental folding fin models with an adjustable free-play are tested in a wind *** fin structure is modeled using the free-interface component mode synthesis method,and its free-play is modeled as four independent nonlinear springs with asymmetric stiffness.A nonplanar unsteady vortex-lattice method considering compressibility is employed to address nonlinear deformation and high subsonic *** spline interpolation is improved through projection and *** aeroelastic characteristics of folding fins with different free-play magnitudes,initial conditions and elastic-axis positions are analyzed using an established time-marching method because of its relatively small computation scale and high *** results show good consistency among the presented method,the wind tunnel test and the harmonic balance *** is a negative correlation between the critical speed of divergent motion and the ratio of the initial condition to the free-play *** either the free-play magnitude or the initial condition is extreme(tiny or vast),the system nonlinearity degenerates to ***,the flutter prevention design of a linear model can be applied to a nonlinear model,such as moving the elastic-axis position *** presented fin configuration exhibits an unstable limit cycle oscillation because the orders of coupled flutter modes do not change with variations in equivalent linear stiffness.

关键词： Free-play Limit cycle oscillation Flutter Component mode synthesis Vortex-lattice method

来源：评论

学校读者我要写书评

暂无评论

Advancing heat-tolerant composites with coherent ladder interfaces via constructing extremely fine nanolamellar solute-twining architectures

引用

Journal of Materials science & Technology 2024年第19期186卷 188-198页

作者： Xue Li Zhenying Huang Hongjie Wang Weici Zhuang Min Zhang Wenqiang Hu Qun Yu Youbo Wu Yang Zhou Institute of Materials Science and Engineering School of Mechanical and Electronic Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Tangshan Research Institute of Beijing Jiaotong University Tangshan 063000China

The interface of ceramic particles and metal matrixes extremely impacts the mechanical properties of particle-reinforced metal matrix composites,especially at elevated *** provide a strategy for constructing extremely fine,in situ-formed coherent nanolamellar solute-twining architectures in a supersaturated MAX/Ni composite to modify the interface,aiming for higher *** this unique architecture,a coherent interface of ceramic particles and a metal matrix is formed,with an enormous coherent interface known as a ladder *** tensile strength at 1023 K is approximately 1 GPa by forming a thermally stable Schwarz crystal structure(<3 nm).Developing heat-tolerant composites using this architecture may enhance the materials’available properties for high-temperature applications.

关键词： Modified coherent interfaces Extremely fine nanograins-nanotwins Nanolamellar architectures Thermal stability Particle-reinforced nickel matrix composites MAX phases

来源：评论

学校读者我要写书评

暂无评论

Stabilising intrinsic room-temperature ferromagnetic two-dimensional semimetallic Cr_(2)CT_(x)MXene by epitaxial self-intercalation of H_(2)O-etched Cr_(2)(AlLi)C

引用

Journal of Advanced Ceramics 2024年第10期13卷 1546-1552页

作者： Xue Li Zhenying Huang Hongjie Wang Wenqiang Hu Weici Zhuang Qun Yu Youbo Wu Qianwen Sun Yang Zhou Guangjin Chen Junji Mou Zhexuan Zhang Institute of Materials Science and Engineering School of Mechanical and Electronic Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Tangshan Research Institute of Beijing Jiaotong University Tangshan 063000China

Physical properties,such as electrochemical and electromagnetic properties,of two-dimensional MXenes can be improved by enhancing their ***,MXenes fabricated via acid etching contain defects,which affect their physical *** this study,a method to effectively remove Al residues using only water during MXene fabrication while maintaining structural stability is *** fabrication and intercalation of MXenes are controlled via epitaxial self-intercalation of H_(2)O-etched Cr_(2)(AlLi)*** the basis of this mechanism,the room-temperature ferromagnetism of two-dimensional few-layered Cr_(2)CT_(x)MXenes,which has a specific saturation magnetization of~0.26 emu/g and a Curie temperature of>353 K,is experimentally *** calculated electronic band structure implies that the semimetal Cr_(2)CT_(x)MXene has a band gap of 0.75 *** study opens new possibilities for the research and applications of industrial-scale manufacturing of MXenes and 2D semiconductors.

关键词： 2D MXene room-temperature ferromagnetism H_(2)O-etched Cr_(2)(AlLi)C epitaxial self-intercalation semimetal

来源：评论

学校读者我要写书评

暂无评论

Impact time control guidance against maneuvering targets based on a nonlinear virtual relative model

引用

Chinese Journal of Aeronautics 2023年第7期36卷 444-459页

作者： Yuru BIN Hui WANG Defu LIN Yaning WANG Xin SUN School of Aerospace Engineering Beijing Institute of TechnologyBeijing 100081China Beijing Key Laboratory of UAV Autonomous Control Beijing Institute of TechnologyBeijing 100081China Beijing Institute Of Electronic System Engineering Beijing 100854China

Aiming at the problem of high-precision interception of air-maneuvering targets with impact time constraints,this paper proposes a novel guidance law based on a nonlinear virtual relative model in which the origin is attached to the *** this way,the original maneuvering target is transformed into a stationary one.A polynomial function of the guidance command in the range domain with two unknown coefficients is introduced into the virtual model,one of the coefficients is determined to achieve the impact time constraint,and the other is determined to satisfy a newly defined virtual look angle *** meeting the terminal constraints simultaneously,the guidance command can finally be *** resulting solution is represented as a combination of proportional navigation guidance-like term which is aimed to meet the zero miss distance constraint,a bias term for impact time control by adjusting the length of the homing trajectory,and an additional term for target *** simulations demonstrate that the proposed law achieves an acceptable impact time error for various initial conditions against different types of maneuvering targets and shows more effective performance in comparison with those of other existing guidance laws.

关键词： Impact time control Maneuvering targets Polynomial guidance Virtual relative model Virtual look angle constraint

来源：评论

学校读者我要写书评

暂无评论

Barrier Construction of the Homicidal Chauffeur Game Considering Speed Descent of the Car

Barrier Construction of the Homicidal Chauffeur Game Conside...

引用

2024 IEEE International Conference on control science and systems engineering, ICCSSE 2024

作者： Zhan, Ziyi Zhang, Yiqun Zhang, Pengfei Control Science and Engineering Beijing Institute of Electronic System Engineering Beijing China Institute of Mechanics Chinese Academy of Sciences Beijing China

ISBN: (纸本)9798331517199

The Homicidal Chauffeur game is a classic pursuit-evasion problem for its significant application in aerospace, robot control, and military. Different from the well-known Isaacs' Homicidal Chauffeur game in which the car's speed is constant, we assume that the car's speed decreases during turns, reflecting the energy limitations in real-world applications. The paper aims to derive the optimal strategies and construct a barrier separating the capture and evasion zones. Initially, we simplify the six- dimensional problem to a three-dimensional one. Subsequently, we deduce the optimal strategy and construct the barrier using the Hamilton-Jacobi-Isaacs equation and backward induction method. A new barrier appears where the optimal strategy of the pursuer is different from the traditional one. That is, when the pursuer's speed is greater than a critical value, the optimal strategy is to apply maximum control;when the pursuer's speed is less than the critical speed, the optimal strategy is to apply zero control. © 2024 IEEE.

关键词： barrier construction Hamilton-Jacobi-Isaacs Homicidal Chauffeur games optimal strategy speed descent

来源：评论

学校读者我要写书评

暂无评论

Point-Voxel Based Geometry-Adaptive Network for 3D Point Cloud Analysis

引用

Journal of Computer science & Technology 2024年第5期39卷 1167-1179页

作者： Tian-Meng Zhao Hui Zeng Bao-Qing Zhang Hong-Min Liu Bin Fan Beijing Engineering Research Center of Industrial Spectrum Imaging School of Automation and Electrial Engineering University of Science and Technology BeijingBeijing 100083China Shunde Innovation School University of Science and Technology BeijingFoshan 528399China Beijing Institute of Electronic System Engineering Beijing 100854China School of Intelligence Science and Technology University of Science and Technology BeijingBeijing 100083China Institute of Artificial Intelligence University of Science and Technology BeijingBeijing 100083China

Point cloud analysis is challenging because of the unordered and irregular data structure of point *** describe geometric information in point clouds,existing methods mainly use convolution,graph,and attention operations to construct sophisticated local aggregation *** operators work well in extracting local information but bring unfavorable inference latency due to high computation *** solve the above problem,this paper presents a novel point-voxel based geometry-adaptive network(PVGANet),which combines multiple representations of point and voxel to describe the point cloud from different granularities and can obtain features of different scales *** extract fine-grained geometric features,we design the position-adaptive pooling operator,which uses point pairs’relative position and feature similarity to weight and aggregate the point features at local areas of point *** extract coarse-grained local features,we design a depth-wise convolution operator,which conducts the depth-wise convolution on voxel *** an easy addition,fine-grained geometric and coarse-grained local features can be fused,and we can use the geometry-adaptive fused features to complete the efficient shape analysis of point clouds,such as shape classification and part *** experiments on ModelNet40,ScanObjectNN,and ShapeNet Part benchmarks demonstrate that our PVGANet achieves competitive performance compared with the related methods.

关键词： point cloud geometric feature multi-representation part segmentation shape classification

来源：评论

学校读者我要写书评

暂无评论

Research on Digital Twin system Platform Framework and Key Technologies of Unmanned Ground Equipment

引用

Complex system Modeling and Simulation 2024年第2期4卷 109-123页

作者： Kunyu Wang Lin Zhang Cheng Xu Han Lu Zhen Chen Hongbo Cheng Rui Guo the School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China the State Key Laboratory of Intelligent Manufacturing System Technology Beijing 100854China the Beijing Institute of Electronic System Engineering Beijing 100854China

As an emerging technology,digital twin is expected to bring novel application modes to the whole life cycle process of unmanned ground equipment,including research and development,design,control optimization,operation and maintenance,*** highly dynamic,complex,and uncertain characteristics of unmanned ground equipment and the battlefield environment also pose new challenges for digital twin *** from the new challenges faced by the digital twin of unmanned ground equipment,this paper designs a service-oriented cloud-edge-end collaborative platform architecture of the digital twin system of unmanned ground equipment,and further analyzes several key technologies supporting the implementation of the platform architecture.

关键词： unmanned ground equipment digital twin native cloud platform Modeling and Simulation(M&S) artificial intelligence

来源：评论

学校读者我要写书评

暂无评论

Hydrogen-induced delayed fracture of Cu-containing high-strength bolt steel

引用

Journal of Iron and Steel Research International 2023年第2期30卷 375-383页

作者： Xiao-li Zhao Cheng-xiang Zhang Yong-jian Zhang Wei-jun Hui Xiu-ming Zhao Materials Science and Engineering Research Center School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing100044China School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing211167JiangsuChina

The hydrogen-induced delayed fracture(HIDF)behavior of a 1300-MPa-grade high-strength bolt steel 42CrMoV containing 0.42 wt.%Cu was investigated by constant load tensile test in a pH 3.5 Walpole *** is shown that the addition of Cu is beneficial to enhance the HIDF resistance by~13%.The observation of the fracture surface revealed that the area fraction of brittle crack initiation zone decreased remarkably for the Cu-added *** the corrosion pit depth and the corrosion rate of the Cu-added steel in the Walpole solution are notably decreased,which is primarily because of the formation of a Cu-rich protective compact rust layer and slightly higher corrosion *** a result,the absorbed hydrogen content in that solution was also decreased by~21%.It is concluded that the improvement in the HIDF resistance of the tested steel is primarily due to the increase in corrosion resistance and resultant decrease in the absorbed diffusible hydrogen content in the acidic condition.

关键词： Hydrogen-induced delayed fracture Hydrogen embrittlement High-strength bolt steel Copper Corrosion

来源：评论

学校读者我要写书评

暂无评论

Fabrication of combustion pyrotechnics for laser and electromagnetic interference shielding

引用

Defence Technology（防务技术） 2023年第6期24卷 140-147页

作者： Yuan-yuan Yao Shao-hua Jin Jing Huang Dong-ze Li Bo-lin Xu Xi-juan Lv Qing-hai Shu School of Materials Science and Engineering Beijing Institute of TechnologyBeijing100081China School of Physics Beijing Institute of TechnologyBeijing100081China Beijing Institute of Electronic System Engineering Beijing100854China State-owned Changhong Machinery Factory Guilin541002China

The contradiction between flammability and packing density is the technical bottleneck for combustible smoke ***,polyurethane(PU)foams with flammability and resilience were prepared with polyol and isocyanate as raw materials by chemical foaming method,then compounded with metal powders,polytetrafluoroethylene(PTFE),phthalic annychide(PA),*** a certain proportion and pressed into pyrotechnic grain to obtain eco-friendly combustion aerosols with compact density of about1.15 g/cm^(3).The resulting combustion smoke agent combined the advantages of PU foam and pyrotechnic with easy ignition,large smoke production,long duration and low environmental *** transmittance of aerosols for 532 nm and 1064 nm lasers was close to 0,and the EMI SE reached up to65 d B and 35 d B in GPS band and X band,*** addition,the resulting pyrotechnic grains exhibited good mechanical strength and elasticity for sample 1:25,with a compressive strength of22 MPa and an elastic modulus of 195 *** resulting combustion smoke agent is expected to play a potential role in the field of electromagnetic damage and protection.

关键词： Smoke agent Flammability PU foam Laser masking EMI shielding

来源：评论

学校读者我要写书评

暂无评论

Modeling and Experimental Study of an Open Two-Phase Loop Driven by Osmotic Pressure and Capillary Force

引用

Frontiers in Heat and Mass Transfer 2025年第1期23卷 55-70页

作者： Hanli Bi Zheng Peng Chenpeng Liu Zhichao Jia Guoguang Li Yuandong Guo Hongxing Zhang Jianyin Miao National Key Laboratory of SpacecraftThermal Control Beijing Institute of Spacecraft System EngineeringChina Academy of Space TechnologyBeijing100094China School of Aeronautical Science and Engineering Beihang UniversityBeijing100083China School of Energy and Environment Engineering University of Science and Technology BeijingBeijing100083China

As space technology advances,thermal control systems must effectively collect and dissipate heat from distributed,multi-source *** heat pipe is a highly reliable two-phase heat transfer component,but it has several limitations when addressing multi-source heat *** by the transport and heat dissipation system of plants,large trees achieve stable and efficient liquid supply under the influence of two driving forces:capillary force during transpiration in the leaves(pull)and root pressure generated by osmotic pressure in the roots(push).The root pressure provides an effective liquid supply with a driving force exceeding 2 MPa,far greater than the driving force in conventional capillary-pumped two-phase *** has shown that osmotic heat pipes offer a powerful driving force,and combining osmotic pressure with capillary force has significant ***,this paper designs a multi-evaporator,dual-drive two-phase loop,using both osmotic pressure and capillary force to solve the multi-source heat dissipation ***,a transmembrane water flux model for the osmotic pressure-driven device was established to predict the maximum heat transfer capacity of the dual-drive two-phase ***,an experimental setup for a multi-evaporator“osmotic pressure+capillary force”dual-drive two-phase loop was constructed,capable of transferring at least 235 W of power under a reverse gravity condition of 20 *** study also analyzed the effects of reverse gravity height,heat load distribution among the three evaporators,startup sequence,and varying branch resistances on the performance of the dual-drive two-phase loop.

关键词： Multi-heat sources osmotic pressure two-phase loop dual-drive loop heat pipe

来源：评论

学校读者我要写书评

暂无评论

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案：

请选择收藏分类：

通借通还

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：