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Flexible liquid metal electromagnetic shielding materials

science china(Technological sciences) 2023年第10期66卷 2757-2774页

作者： BAI YunLong ZHANG Jie ZHANG MingKuan RAO Wei Key Laboratory of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China Beijing Key Lab of CryoBiomedical Engineering and Key Lab of Cryogenics Technical Institute of Physics and ChemistryChinese Academy of SciencesBeijing 100190China School of Engineering Science University of Chinese Academy of SciencesBeijing 100039China School of Future Technology University of Chinese Academy of SciencesBeijing 100049China Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China

The demand for flexible shielding has been rapidly growing in recent *** materials using solid metals,carbon materials,or MXenes as shielding units usually have difficulty in combining high shielding and flexibility(stretching and bending characteristics),and thus they gradually fail to meet the shielding needs of flexible ***,shielding materials with both flexibility and high conductivity are urgent to fill this ***-based room temperature liquid metal(LM)is an emerging functional material with a low melting point,low viscosity,low modulus,and easy ***,due to wettability and compatibility issues,it is difficult to apply bulk LMs directly in the field of electromagnetic shielding(EMS).The article reviews the fabrication methods,performance,and applications of LMs EMS materials from three perspectives:Macroscopic LMs,micro/nano-LMs,and LM-based *** gallium-based liquid EMS materials demonstrate the characteristics of high shielding performance with stretchability and a wide shielding *** this review,different types of gallium-based LM materials are described from macroscopic to microscopic,from liquid to semi-solid,from high density to low density,from room temperature to ultra-low temperature,and from monolayer structure to multilayer *** prospect of LM materials as amorphous high-performance EMS materials is demonstrated in various applications,such as mobile communication,astronomical observation,radar,and medical detection,showing tremendous potential in the EMS field.

关键词： liquid metal electromagnetic shielding flexibility

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Nonreciprocity of energy transfer in a nonlinear asymmetric oscillator system with various vibration states

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Applied Mathematics and Mechanics(English Edition) 2023年第5期44卷 727-744页

作者： Jian’en CHEN Jianling LI Minghui YAO Jun LIU Jianhua ZHANG Min SUN Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical EngineeringTianjin University of TechnologyTianjin 300384China National Demonstration Center for Experimental Mechanical and Electrical Engineering Education Tianjin University of TechnologyTianjin 300384China School of Aeronautics and Astronautics Tiangong UniversityTianjin 300387China Agricultural Information Institute of Chinese Academy of Agricultural Sciences Key Laboratory of Agricultural Big DataMinistry of Agriculture and Rural AffairsBeijing 100081China School of Science Tianjin Chengjian UniversityTianjin 300384China

The nonreciprocity of energy transfer is constructed in a nonlinear asymmetric oscillator system that comprises two nonlinear oscillators with different parameters placed between two identical linear *** slow-flow equation of the system is derived by the complexification-averaging *** semi-analytical solutions to this equation are obtained by the least squares method,which are compared with the numerical solutions obtained by the Runge-Kutta *** distribution of the average energy in the system is studied under periodic and chaotic vibration states,and the energy transfer along two opposite directions is *** effect of the excitation amplitude on the nonreciprocity of the system producing the periodic responses is analyzed,where a three-stage energy transfer phenomenon is *** the first stage,the energy transfer along the two opposite directions is approximately equal,whereas in the second stage,the asymmetric energy transfer is *** energy transfer is also asymmetric in the third stage,but the direction is reversed compared with the second ***,the excitation amplitude for exciting the bifurcation also shows an asymmetric *** vibrations are generated around the resonant frequency,irrespective of which linear oscillator is *** excitation threshold of these chaotic vibrations is dependent on the linear oscillator that is being *** addition,the difference between the energy transfer in the two opposite directions is used to further analyze the nonreciprocity in the *** results show that the nonreciprocity significantly depends on the excitation frequency and the excitation amplitude.

关键词： nonreciprocity strong nonlinearity energy transfer chaotic vibration higher branch of response

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PCA-W: An Simulation Algorithm for Waterlogging in Ground Point Cloud Based on Principal Component Analysis 3

PCA-W: An Simulation Algorithm for Waterlogging in Ground Po...

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3rd International Conference on Big Data, Information and Computer Network, BDICN 2024

作者： Duan, Yucong Zhang, Yifan Xu, Ziwen Ma, Jie National Key Laboratory of Science and Technology on Multi-spectral Information Processing School of Artificial Intelligence and Automation Huazhong University of Science and Technology Hubei Wuhan China China Ship Development and Design Center Wuhan Hubei China

ISBN: (纸本)9798350363821

In the context of autonomous driving, ground point clouds play an important role in system decision-making. However, in the case of adverse weather, ground point clouds may suffer from a certain degree of missing data, which will have a negative impact on some downstream tasks of autonomous driving. With the development of autonomous driving algorithms, deep learning has achieved better results in this field. However, due to the lack of point cloud data sets under adverse weather conditions, the network cannot be effectively trained. This paper proposes a simulation algorithm for ground point clouds with water accumulation, which simulates the phenomenon of missing data in the ground point clouds due to road water accumulation in adverse weather. As a data augmentation method, it can expand the data set for downstream tasks. We evaluated the method on the STF dataset and proved its effectiveness. © 2024 IEEE.

关键词： Decision making

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An architecture decomposition method of pneumatic catapult system based on OPM and DSM

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Chinese Journal of Aeronautics 2023年第8期36卷 168-181页

作者： Lu GAN Gang YANG Xianhui LI Enze ZHU Hu CHEN Xiaohui WEI State Key Laboratory of Mechanics and Control of Aerospace Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China Key Laboratory of Fundamental Science for National Defense-Advanced Design Technology of Flight Vehicle Nanjing University of Aeronautics and AstronauticsNanjing 210016China College of General Aviation and Flight Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The architecture strategy of the Unmanned Aerial Vehicle(UAV)pneumatic launch system should continue to evolve to adapt to complex and variable operating *** representation,decomposition perspective,and cluster analysis play a vital role in the early phase of system architecture *** order for the system to emerge anticipated and desirable intrinsic functional properties,an architecture decomposition method based on the ObjectProcess Methodology(OPM)and design Structure Matrix(DSM)is put forward in this *** OPM is proposed to model the UAV launch process formally,and the matrix representation of the architecture of the pneumatic launch system is *** the extension of the definition and operations of DSM,with the Idicula-Gutierrez-Thebeau Algorithm plus(IGTA+)clustering algorithm,the transformation of the pneumatic launch system architecture from process decomposition to function decomposition is demonstrated in this *** analysis shows that the architecture decomposition of the pneumatic launch system meets the functional requirements of stakeholders.

关键词： Architecture decomposition Cluster analysis design structure matrix Object-process methodology Pneumatic catapult system

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BDGSE: A Symbolic Execution Technique for High MC/DC 23

BDGSE: A Symbolic Execution Technique for High MC/DC

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23rd IEEE International Conference on Software Quality, Reliability, and Security, QRS 2023

作者： Cai, Huangli Zhang, Zhiyi Jian, Yifan Li, Dan Huang, Zhiqiu Nanjing University of Aeronautics and Astronautics Collage of Computer Science and Technology Nanjing China Collaborative Innovation Center of Novel Software Technology and Industrialization Nanjing China Nuclear Power Institute of China Science and Technology on Reactor System Design Technology Laboratory Chengdu China Nanjing University of Aeronautics and Astronautics Ministry Key Laboratory for Safety-Critical Software Development and Verification Nanjing China

ISBN: (纸本)9798350319583

Modified Condition/Decision Coverage (MC/DC) is a test coverage standard with excellent fault detection capability, which is widely used in testing safety-critical software. Symbolic execution generates test cases automatically to achieve high code coverage. However, since symbolic execution uses short-circuit evaluation to evaluate decisions, it fails to guarantee the consistency of other conditions in a decision required by the MC/DC criterion. As a result, it is incapable of generating MC/DC test cases to test safety-critical systems adequately. To solve this problem, we propose Branch Dependence Guided Symbolic Execution (BDGSE), a symbolic execution technique for high MC/DC. The approach utilizes static analysis to compute the branch dependencies, then guides symbolic execution to selectively explore paths and simplify test cases, and finally generates a small number of test cases to achieve high MC/DC coverage. Our experimental results show that BDGSE can generate high-quality test cases. Although BDGSE generates fewer test cases, it can achieve higher MC/DC coverage than SPF and random methods, and the fault detection capability of test cases generated by BDGSE is comparable to that of test cases generated by SPF. © 2023 IEEE.

关键词： Software testing

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Synthesis Optimization of SSZ-13 Zeolite Membranes by Dual Templates for N_(2)/NO_(2) Separation

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Chemical Research in Chinese Universities 2022年第1期38卷 250-256页

作者： LI Jun RONG Huazhen CHEN Cong LI Ziyi ZUO Jiayu WANG Wenjian LIU Xinjian GUAN Yixing YANG Xiong LIU Yingshu ZOU Xiaoqin ZHU Guangshan School of Energy and Environmental Engineering University of Science and Technology BeijingBeijing 100083P.R.China Faculty of Chemistry Northeast Normal UniversityChangchun 130024P.R.China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of ChinaChengdu 610213P.R.China

High-silica SSZ-13 zeolite membranes are promising in industrial separations of light gases and continuous membranes are highly demanded for better separation performances. Herein, pure-phase, continuous and thin SSZ-13 zeolite membranes were synthesized using dual templates of N,N,N-trimethtyl-1-adamantammonium hydroxide(TMAdaOH) and tetraethylammonium hydroxide(TEAOH). systematical investigations of TMAdaOH/TEAOH ratios and their concentrations show that TMAdaOH acts as the main structure-directing agent in the formation of the SSZ-13 zeolite. TMAdaOH cooperatively plays with TEAOH in promoting the SSZ-13 crystal intergrowth to form a continuous polycrystalline membrane. Additionally, appropriate introduction of TEAOH is able to adjust the membrane thickness to the crystal-comparable size of ca. 2.0 μm. The SSZ-13 membranes are further applied for N2/NO2separation, which is firstly reported on zeolite membranes. The gas permeation results show that the SSZ-13 membrane synthesized by the dual-template approach exhibits selective separation of N2 over NO2 with N2/NO2 separation factor of 7.6 and N2 permeance of 1.66×10-8 mol·m-2·s-1·Pa-1.

关键词： Zeolite membrane Dual template SSZ-13 Gas separation Nitrogen dioxide

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Research on Causal Model Construction and Fault Diagnosis of Control systems 7th

Research on Causal Model Construction and Fault Diagnosis of...

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7th International Conference on Computing, Control and Industrial Engineering, CCIE 2023

作者： Zhu, Qun Chen, Zhi Liu, Jie Xu, Zhuoran Wen, Juan Yang, Jinghua Jian, Yifan School of Computer Science University of South China Hengyang421200 China Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610064 China School of Electrical Engineering University of South China Hengyang421200 China

ISBN: (纸本)9789819927296

Fault diagnosis of complex control systems is a difficult and hot topic of research at this stage. In order to explore the internal operation characteristics of complex control systems and fault propagation methods to achieve efficient and accurate fault diagnosis, this paper studies control system fault diagnosis methods based on cause-effect relationships, analyzes the role relationship between system components from the perspective of control equation structure, proposes the method of constructing cause-effect diagram models with control equations, and uses the algorithm of way to implement, and then combine the information flow to quantify the causal effect quantifiably, when the system steady state is disrupted, the information flow produces a jump, so as to extend the fault diagnosis reasoning method. The fault diagnosis is verified by simulation of the pressure control system of the nuclear power plant regulator, and the experimental results verify the effectiveness of the proposed method. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.

关键词： Failure analysis

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Rapid Modeling and Model Order Reduction of Launch Vehicle Based on Digital Twin 2nd

Rapid Modeling and Model Order Reduction of Launch Vehicle B...

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2nd International Conference of Mechanical system Dynamics, ICMSD 2023

作者： Huang, Tianyou Wang, Qingtao Liu, Xiong Liu, Zhendong Wang, Qixiao School of Science Nanjing University of Science and Technology Nanjing China Institute of Launch Dynamics Nanjing University of Science and Technology Nanjing China National Key Laboratory of Complex Multibody System Dynamics Nanjing University of Science and Technology Nanjing China Shanghai Aerospace Systems Engineering Institute Shanghai China

ISBN: (纸本)9789819980475

In this paper, a dynamic analysis technique for complex launch vehicle models using digital twin technology is introduced. A parameterized model of the launch vehicle is established and simulations are conducted on a multi-physics simulation platform. The resulting analysis file is then integrated into a system-level multi-physical domain digital twin platform. To simplify the model, singular value decomposition (SVD) method is employed to reduce its complexity. Numerical comparison and error analysis are performed between the reduced model and the original model. By comparing and analyzing the reduced order models with different levels of error, the effectiveness of the digital twin approach is demonstrated. Furthermore, the reduced order model within the digital twin framework is encapsulated. This encapsulation enables the realization of comprehensive life cycle configuration management for the launch vehicle equipment. Overall, this technique offers a promising approach for analyzing and managing complex models of the context of launch vehicles. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Launch vehicles

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Study and Analysis of the Effect of Dynamic Load on the Application of Lbb technology to the Primary Pipe of reactor Coolant system

SSRN

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SSRN 2024年

作者： He, Feng Xiong, Furui Bai, Xiaoming Yang, Kang Lu, Xifeng Li, Bingjin Wang, Xinjun Science and Technology on Reactor System Design Technology Laboratory Nuclear Power Institute of China Chengdu610213 China

reactors may be subjected to dynamic loads, and in order to ensure that Leak-Before-Break (LBB) technology is safely and reliably applied to the primary piping of reactor coolant system, dynamic load impact analysis of LBB technology applied to the primary piping was performed. The dynamic mechanical properties test was carried out on the primary piping, and the crack leakage rate test under dynamic load and the impact load loading test under different loading speeds were carried out on the primary piping test piece with circumferential penetrating crack. Based on experimental data, the crack leakage rate analysis method and crack stability analysis method in quasi-static LBB technology were used to analyze the impact of applying LBB technology to the primary piping under dynamic load. The analysis results indicate that, when LBB technology is applied to the primary piping of reactor coolant system, the analysis results under dynamic load are more conservative than those under quasi-static load, and it is safer and more reliable under dynamic loads in practical engineering applications. © 2024, The Authors. All rights reserved.

关键词： Dynamic loads

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Parameterized Modelling of Stage Separation of Launch Vehicles with Modelica 2nd

Parameterized Modelling of Stage Separation of Launch Vehicl...

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2nd International Conference of Mechanical system Dynamics, ICMSD 2023

作者： Zhang, Wenfeng Cai, Xiaoshuang Liu, Zhendong Liu, Xiong Tong, Yifan Shanghai Aerospace Systems Engineering Institute Shanghai China School of Science Nanjing University of Science and Technology Nanjing China Institute of Launch Dynamics Nanjing University of Science and Technology Nanjing China National Key Laboratory of Complex Multibody System Dynamics Nanjing University of Science and Technology Nanjing China

ISBN: (纸本)9789819980475

In order to improve launching capability and performance, almost all launch vehicles in active service contain two or more stages. During the launch process, it is of vital importance to gradually reduce the weight of the launch vehicles by separating and jettisoning spent stages which have burned out its propellant. The separation process between the stages plays a crucial role in guaranteeing the safety of the launch vehicles and ensuring a successful launch. Consequently, it is essential for launch vehicle designers to well understand the stage-separation dynamics which is quite complex and affected by many system parameters. To evaluate the impact of the system parameters on the stage-separation mission, a parameterized model is established for a two-stage launch vehicle using the Modelica language along with the software MWorks. As representative parameters to evaluate, the mass-center positions of the first and second stages, both the positions and directions of the active forces, the residual thrusts, the positive thrusts, the retro thrusts, the masses and moments of inertia of the two stages, are all taken into account for dynamic analysis. The parameterized Modelica model is built by exploiting the idea of the equation-based causal modelling to numerically simulate the stage-separation process and evaluate the influence of the parameters on the system responses. Simulation results based on representative case studies indicate that the separation process of the first and second stages can be well described by the Modelica model. Besides, a comparison with Adams software demonstrates the results of the Modelica model agree well with those obtained using Adams. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.

关键词： Launch vehicles

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