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An improved EMMS model for turbulent flow in pipe and its solution

Particuology 2023年第5期76卷 1-12页

作者： Lin Zhang Wen Lai Huang Jianhua Chen State Key Laboratory of Multiphase Complex Systems Institute of Process EngineeringChinese Academy of SciencesBeijing100190China

Based on the existing energy-minimization multi-scale(EMMS)model for turbulent flow in pipe,an improved version is proposed,in which not only a new radial velocity distribution is introduced but also the quantification of total dissipation over the cross-section of pipe is improved for the dominant mechanism of fully turbulent flow in *** four dynamic equality constraints and some other constraints are constructed but there are five parameters involved,leading to one free variable *** the compromise in competition between dominant mechanisms for laminar and fully turbulent flow in pipe respectively,the above four constructed dynamic equality constraints can be ***,the cases for turbulent flow in pipe with low,moderate and high Reynolds number are simulated by the improved EMMS *** numerical results show that the model can obtain reasonable results which agree well with the data computed by the direct numerical simulation and those obtained by *** illustrates that the improved EMMS model for turbulent flow in pipe is reasonable and the compromise in competition between dominant mechanisms is indeed a universal governing principle hidden in complex ***,one more EMMS model for a complex system is offered,pro-moting the further development of mesoscience.

关键词： Mesoscience EMMS Compromise in competition Dominant mechanism Turbulent flow in pipe

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Multi-modal Bionic Motion Analysis of A Cpg-controlled Pneumatic Soft Robot

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Journal of Bionic Engineering 2024年第5期21卷 2247-2257页

作者： Yu Zhang Peiyu Huang Dongjie Li Jiangyu Zhou Yu Li Bo You Yanhe Zhu Heilongjiang Provincial Key Laboratory of Complex Intelligent System and Integration Harbin University of Science and TechnologyHarbin150080China State Key Laboratory of Robotics and System Harbin Institute of Technology(HIT)Harbin150001China

This paper designs a soft robot with a multi-chamber,multi-airbag mimicking soft biological structure,where the airbags of the same chamber are interconnected with each *** upper and lower chambers are separated by an intermediate layer(thin plate),which is extended and widened to achieve robot movement and *** applying pressure to the different chambers of the soft robot,it is possible to produce a variety of bionic movements of the inchworm and *** to the strong nonlinearity and infinite number of degrees of freedom properties of the material,it is impossible to obtain the analytical solution of the bending morphology and pressure of the soft robot ***,a method to establish a mathematical model of soft robot deformation based on the classical stacked plate theory is proposed,and a chain composite model of soft robot bending motion is established based on the large-deflection modeling *** paper proposes a method to generate a multi-mode soft robot motion control based on the Central Pattern Generator(CPG)using a single controller,which achieves the switching of sine wave-like patterns,half-wave-like patterns,and dragging patterns by adjust-ing frequency,amplitude and period of ***,a pneumatic control platform is built for the validation of the theoretical model and different experimental models of the motion of the *** comparation of the different motion modes of the soft robot under similar non-load and load conditions.

关键词： Soft robot Bionic multi-modal movement Laminated plate theory CPG control

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Detection method of forward-scatter signal based on Rényi entropy

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Journal of systems Engineering and Electronics 2024年第4期35卷 865-873页

作者： ZHENG Yuqing AI Xiaofeng YANG Yong ZHAO Feng XIAO Shunping State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense TechnologyChangsha 410073China

The application scope of the forward scatter radar(FSR)based on the Global Navigation Satellite system(GNSS)can be expanded by improving the detection ***,the forward-scatter signal model when the target crosses the baseline is ***,the detection method of the for-ward-scatter signal based on the Rényi entropy of time-fre-quency distribution is proposed and the detection performance with different time-frequency distributions is ***-tion results show that the method based on the smooth pseudo Wigner-Ville distribution(SPWVD)can achieve the best ***,combined with the geometry of FSR,the influence on detection performance of the relative distance between the target and the baseline is ***,the proposed method is validated by the anechoic chamber measurements and the results show that the detection ability has a 10 dB improvement compared with the common constant false alarm rate(CFAR)detection.

关键词： forward scatter radar(FSR) Global Navigation Satellite system(GNSS) time-frequency distribution Rényi entropy signal detection

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An angular blinking jamming method based on electronically controlled corner reflectors

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Journal of systems Engineering and Electronics 2024年第2期35卷 330-338页

作者： GAN Lin WU Zehao WANG Xuesong LI Jianbing State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System National University of Defense TechnologyChangsha 410073China

Passive jamming is believed to have very good potential in countermeasure *** this paper,a passive angular blinking jamming method based on electronically controlled corner reflectors is *** amplitude of the incident wave can be modulated by switching the corner reflector between the penetration state and the reflection state,and the ensemble of multiple corner reflectors with towing rope can result in complex angle decoying *** of the decoying effect on corner reflectors’radar cross section and positions are analyzed and *** show that the angle measured by a monopulse radar can be significantly interfered by this method while the automatic tracking is employed.

关键词： monopulse radar angular blinking jamming corner reflector amplitude-comparison angle measurement metasurface

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3D coarse-grained DPM simulation of the MIP reaction-regeneration loop

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Particuology 2024年第6期89卷 57-66页

作者： Yanhao Ye Shuai Zhang Ji Xu Wei Ge State Key Laboratory of Mesoscience and Engineering(formerly State Key Laboratory of Multiphase Complex Systems) Institute of Process EngineeringChinese Academy of SciencesBeijing100190China School of Chemical Engineering University of Chinese Academy of SciencesBeijing100049China

The reactor-regenerator loop is the core facility of the maximizing iso-paraffin(MIP)*** the discrete particle method(DPM)simulation can provide detailed information at the particle scale,it has been unable to simulate such a complex loop system due to limitations of coarse-grained(CG)models,computing software,and *** this study,a newly proposed soft-shell CG-DPM model with a CG ratio of up to 800 is used to simulate a 3.5 Mt/a industrial-scale MIP reactor-regenerator *** solid fraction distribution obtained is found to agree well with in-situ *** properties including the distribution of solid fraction,gas and solid velocity,standard derivation of solid fraction with time,temporal distribution of the flow field,and particle residence time distribution are measured in the simulation,which are meaningful to better design and operate such systems in the future.

关键词： Discrete particle method Coarse-grain Maximizing iso-paraffins Full-loop Reaction-regeneration system

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Contact Force Optimization to Enhance Fault-tolerant Motion Stability of a Hexapod Robot

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Journal of Bionic Engineering 2024年第5期21卷 2199-2214页

作者： Bo You Shangdong Shi Chen Chen Jiayu Li Nan Li Liang Ding The Key Laboratory of Intelligent Technology for Cutting and Manufacturing Ministry of Education and the Heilongjiang Provincial Key Laboratory of Complex Intelligent System and Integration Harbin University of Science and TechnologyHarbin150080China The State Key Laboratory of Robotics and System Harbin Institute of TechnologyHarbin150001China

This paper presents a novel method for optimizing the contact force of a hexapod robot to enhance its dynamic motion stability when one of its legs *** proposed approach aims to improve the Force Angle Stability Margin(FASM)and adapt the foot trajectory through contact force optimization to achieve safe and stable motion on various *** foot force optimization approach is designed to optimize the FASM,a factor rarely considered in existing contact force optimization *** formulating the problem of enhancing the motion stability of the hexapod robot as a Quadratic Programming(QP)optimization problem,this approach can effectively address this *** of a hexapod robot using a fault-tolerant gait,along with real field experiments,were conducted to validate the effectiveness and feasibility of the contact force optimization *** results demonstrate that this approach can be used to design a motion controller for a hexapod robot with a significantly improved motion *** summary,the proposed contact force optimization method offers a promising solution for enhancing the motion stability of hexapod robots with single leg failures and has the potential to significantly advance the development of fault-tolerant hexapod robots for various applications.

关键词： Hexapod robot Fault-tolerant Stability margin Contact force optimization

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Source enumeration method by combining diagonal loading and constructing second-order statistics

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The Journal of China Universities of Posts and Telecommunications 2023年第1期30卷 47-55页

作者： Wang Chuanchuan Zeng Yonghu Wang Liandong Li Zhipeng State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System Luoyang 471003China

A source enumeration method based on diagonal loading of eigenvalues and constructing second-order statistics is proposed,for the case that the antenna array observed signals are overlapped with spatial colored noise,and the number of antennas compared with the number of snapshots meet the requirement of general asymptotic ***,the sample covariance matrix of the observed signals is obtained,the eigenvalues of the sample covariance matrix can be acquired by eigenvalue decomposition,and the eigenvalues are diagonally loaded,and a new formula for calculating the diagonal loading is *** on the diagonal loaded eigenvalues,the difference values are calculated for the adjacent eigenvalues after diagonal loading,and the statistical variance of the difference values is *** this basis,the second-order statistics of the difference values are constructed,and when the second-order statistics are minimized,the corresponding number of sources is *** proposed method has wide applicability,which is suitable for both general asymptotic regime and classical asymptotic system,and is suitable for both white Gaussian noise environment and colored noise *** method makes up for the lack of source enumeration methods in the case of general asymptotic system and colored noise.

关键词： source enumeration general asymptotic regime colored noise diagonal loading second-order statistics

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Fast measurement and prediction method for electromagnetic susceptibility of receiver

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Journal of systems Engineering and Electronics 2024年第2期35卷 275-285页

作者： CHEN Yan LU Zhonghao LIU Yunxia State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System College of Electronic Science and TechnologyNational University of Defense TechnologyChangsha 410073China State Key Laboratory of Astronautic Dynamics Xi’an 710043China

Aiming at evaluating and predicting rapidly and accurately a high sensitivity receiver’s adaptability in complex electromagnetic environments,a novel testing and prediction method based on dual-channel multi-frequency is proposed to improve the traditional two-tone ***,two signal generators are used to generate signals at the radio frequency(RF)by frequency scanning,and then a rapid measurement at the intermediate frequency(IF)output port is carried out to obtain a huge amount of sample data for the subsequent ***,the IF output response data are modeled and analyzed to construct the linear and nonlinear response constraint equations in the frequency domain and prediction models in the power domain,which provide the theoretical criteria for interpreting and predicting electromagnetic susceptibility(EMS)of the *** experiment performed on a radar receiver confirms the reliability of the method proposed in this *** shows that the interference of each harmonic frequency and each order to the receiver can be identified and predicted with the sensitivity *** on this,fast and comprehensive evaluation and prediction of the receiver’s EMS in complex environment can be efficiently realized.

关键词： electromagnetic susceptibility(EMS) receiver dualchannel multi-frequency nonlinear response frequency domain power domain

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Rare earth metal based DES assisted the VPO synthesis for n-butane selective oxidation toward maleic anhydride

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Green Energy & Environment 2023年第6期8卷 1737-1752页

作者： Muhammad Faizan Yingwei Li Xingsheng Wang Piao Song Ruirui Zhang Ruixia Liu Beijing Key Laboratory of Ionic Liquids Clean Process CAS Key Laboratory of Green Process and EngineeringState Key Laboratory of Multiphase Complex SystemInstitute of Process Engineering Chinese Academy of SciencesBeijing100190China University of Chinese Academy of Sciences Beijing100049China Zhengzhou Institute of Emerging Industrial Technology Zhengzhou450000China

Deep eutectic solvents(DESs) are now considered a new class of ionic liquid analogs that have been generously used in various ***, vanadium phosphorus oxide(VPO) catalysts are synthesized in combination with a deep eutectic solvent containing rare earth metal(rE-DES), and their catalytic performance in n-butane selective oxidation to produce maleic anhydride(MA) is evaluated. The rE-DES is produced from the interaction of choline chloride(ChCl) and rare earth metal salts(Cerium, Europium, Lanthanum, and Samarium metal salt)(ChCl:rE = 1:0.5–1:3) under mild conditions. It was found that DESs served as structural modifiers and electronic promoters during VPO synthesis. It regulated the chemical state of the catalyst surface, such as the vanadium valence state, acid-base properties, and ratios of V^(4+)/V^(5+),Lat–O/Sur–O and P/V. Various characterization techniques, such as FT-IR, DSC, XRD, SEM, EDS, TEM, Raman, TGA, NH3-TPD, and XPS,were used to examine its physical and chemical characteristics. These characteristics were correlated with the catalytic performance. The VPO catalyst modified by rE-DES showed a significant enhancement of n-butane conversion and MA selectivity while suppressing the selectivity of CO and CO_(2)as well as the CO/CO_(2)ratio compared to the unpromoted VPO catalyst. Especially for Ce-DES-VPO, it increased the n-butane conversion and MA mass yield up to approximately 11% and 10%, respectively. In addition, we evaluated the catalytic performance under different activation atmospheres.

关键词： earth anhydride vanadium

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Recognition and Suppression of Slice Repeater Jamming Based on Coded Waveform

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IEEE Transactions on Aerospace and Electronic systems 2025年第3期61卷 7466-7480页

作者： Xie, Ailun Liu, Xiaobin Wu, Qihua Liu, Zhenyu Xiao, Shunping National University of Defense Technology State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System Changsha410073 China

The slice repeater jamming (SRJ) is coherent with the transmitted waveform and can produce many false targets after pulse compression, making it difficult for radars to detect real targets. To suppress the SRJ, an SRJ recognition and suppression method based on the coded waveform is proposed in this article. First, the design principle of the coded waveform is introduced, and the SRJ characteristics and target characteristics of the coded waveform are revealed by theoretical derivation. By adjusting the coded waveform parameters, the target peaks in the range profile may disappear so that the range profile of the coded waveform is dominated by SRJ. In addition, when subjected to the same SRJ, the positions of false targets in the coded waveform range profile are the same as those in the linear frequency modulation (LFM) waveform range profile, and this property can be used to recognize the false targets in the LFM range profile. Then, based on the relationship between the false targets in the range profiles of the two waveforms, the false targets in the LFM waveform range profile are reconstructed and suppressed. Finally, simulations are conducted to demonstrate that the proposed method is effective against different kinds of SRJ. Compared with the existing methods, the proposed method shows better jamming suppression ability in different signal-to-noise ratio and signal-to-jamming ratio scenarios. © 1965-2011 IEEE.

关键词： Jamming

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