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arXiv 2023年

作者： Cao, Kaiyuan Hu, Yayun Tong, Peiqing Yang, Guangwen Liu, Peng Zhejiang Lab Hangzhou311100 China Department of Physics Institute of Theoretical Physics Nanjing Normal University Nanjing210023 China Jiangsu Key Laboratory for Numerical Simulation of Large Scale Complex Systems Nanjing Normal University Nanjing210023 China Department of Computer Science and Technology Tsinghua University Haidian District Beijing100084 China College of Information Science and Electronic Engineering Zhejiang University Hangzhou310027 China

We investigate the relaxation dynamics of the fermion two-point correlation function Cmn(t) = 〈ψ(t)|c†mcn|ψ(t)〉 in the XY chain with alternating nearest-neighbor hopping interaction after a quench. We find that the deviation δCmn(t) = Cmn(t) − Cmn(∞) decays with time following the power law behavior t−µ, where the exponent µ depends on whether the quench is to the commensurate phase (µ = 1) or incommensurate phase (µ = 1/2). This decay of δCmn(t) arises from the transient behavior of the double-excited quasiparticle occupations and the transitions between different excitation spectra. Furthermore, we find that the steady value Cmn(∞) only involves the average fermion occupation numbers (i.e. the average excited single particle) over the time-evolved state, which are different from the ground state expectation values. We also observe nonanalytic singularities in the steady value Cmn(∞) for the quench to the critical points of the quantum phase transitions (QPTs), suggesting its potential use as a signature of QPTs. Copyright © 2023, The Authors. All rights reserved.

关键词： Ground state

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8D Parameters Estimation for Bistatic EMVS-MIMO Radar via the nested PARAFAC

arXiv

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arXiv 2022年

作者： Xie, Qianpeng Wang, He Du, Yihang Pan, Xiaoyi Zhao, Feng The State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System National University of Defense Technology Changsha410073 China The School of Electronic Science National University of Defense Technology Changsha410073 China The Sixty-Third Research Institute National University of Defense Technology Nanjing210007 China

In this letter, a novel nested PARAFAC algorithm was proposed to improve the 8D parameters estimation performance for the bistatic EMVS-MIMO radar. Firstly, the outer part PARAFAC algorithm was carried out to estimate the receive spatial response matrix and its first way factor matrix. For the estimated first way factor matrix, a theory is given to rearrange its data into an new matrix, which is the mode-1 unfolding matrix of a three-way tensor. Then, the inner part PARAFAC algorithm was used to estimate the transmit steering vector matrix, the transmit spatial response matrix and the receive steering vector matrix. Thus, the transmit 4D parameters and receive 4D parameters can be accurately located via the abovementioned process. Compared with the original PARAFAC algorithm, the proposed nested PARAFAC algorithm can avoid additional reconstruction process when estimating the transmit/receive spatial response matrix. Moreover, the proposed algorithm can offer a highly-accurate 8D parameters estimaiton than that of the original PARAFAC algorithm. Simulated results verify the effectiveness of the proposed algorithm. Copyright © 2022, The Authors. All rights reserved.

关键词： Parameter estimation

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Α-Moc@Cs Carrier Modulated Platinum Single Atoms to Enhance Catalytic Activity in Solar Cells

SSRN

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SSRN 2022年

作者： Yao, Jixin Wang, Jie Wang, Wen Meng, Ying Wang, Haibo Lu, Shibin Du, Feng Yang, Li Zuo, Xueqin Li, Guang Anhui Province Key Laboratory of Simulation and Design for Electronic Information System Universitie s Joint Key Laboratory of Photoelectric Detection Science and Technology Hefei Normal University Anhui Province Hefei230601 China School of Materials Science and Engineering Anhui Key Laboratory of Information Materials and Devices Key Laboratory of Structure and Functional Regulation of Hybrid Materials Ministry of Education Institute of Physical Science and Information Technology Anhui University Hefei230601 China Institute of Materials Science and Devices School of Materials Science and Engineering Suzhou China University of Science and Technology Suzhou215011 China

Single-atom electrocatalysts have been proven to be the great promising catalysts for energy-related fields yet their active site structure remains elusive, especially in dye-sensitized solar cell (DSSC). Herein, atomically dispersed Pt is confined into α-MoC@CS carrier (Pt/α-MoC@CS), which vigorously stimulates the activity of Pt single atoms under strong interactions. As expected, the Pt/α-MoC@CS as the cathode in DSSC exhibits high power conversion efficiency (PCE) of 9.87%, exceeding Pt electrode (7.61%). X-ray photoelectron spectroscopy combined with density functional theory calculations reveals that the high activity is mainly derived from charge re-distribution of Pt/α-MoC@CS caused by the interaction between Pt atoms and α-MoC. This interaction not only achieves the optimized adsorption/desorption energy of reactants but also brings synergic advantages to expedite the reaction kinetics of the overall system. This work paves further research prospects for charge re-distribution, stimulating electrocatalysts to effectively enhance their catalytic properties by an atomic-level engineering strategy. © 2022, The Authors. All rights reserved.

关键词： Cathodes

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Manmade Target Scattering Structure Null-Pol Recognition and Application

Manmade Target Scattering Structure Null-Pol Recognition and...

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IEEE International Conference on Radar

作者： GuoQing Wu SiWei Chen YongZhen Li XueSong Wang State Key Laboratory of Complex Electromagnetic Environment Effects on Electronics and Information System (CEMEE) School of Electronic Science and Engineering National University of Defense Technology ChangSha China

ISBN: (纸本)9781665468893

Target's optimal polarization is the fundamental theory of radar polarization. Null-Pol, also called Co-Pol Null, is one of the significant polarization states, through which other optimal polarization states can be derived. Null-Pol theory is widely applied in polarization reception match, contrast enhancement and so on. This paper revealed the advantage of Null-Pol theory in manmade target scattering structure recognition for the first time. The complex polarization ratio plane and polarization response characteristics were combined and the Null-Pol 3D response patterns were represented, which can reveal the difference of canonical scattering structures. Then, the Null-Pol scattering structure recognition method of manmade targets is proposed. The scattering centers are extracted from radar images. The scattering structure type can be identified by matching the Null-Pol response characteristic vectors with canonical scatters. Through the analysis of electromagnetic computation data of manmade targets, the proposed Null-Pol scattering structure recognition method can identify the scattering structure types of manmade targets. Especially, the results of symmetric targets have better performance than Cameron decomposition, which is more consistent with target's actual scattering structure types.

关键词： Polarization Visualization Three-dimensional displays Target recognition Radar Radar scattering Radar imaging

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Decoupling Design Based on Active Disturbance Rejection Control Approach for Near Space Vehicle Autopilot

Decoupling Design Based on Active Disturbance Rejection Cont...

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Chinese Intelligent systems Conference, CISC 2019

作者： Li, Hui Yin, Zhide Li, Fengyi Liu, Hongyu Beijing Electro-Mechanical Institute Beijing100074 China Science and Technology on Complex System Control and Intelligent Agent Cooperation Laboratory Beijing100074 China Beijing Institute of Control and Electronic Technology Beijing100038 China

ISBN: (纸本)9789813296855

A decoupled control approach based on linear active disturbance rejection control idea is proposed. The plant model, in which the coupling dynamics is as a part of disturbance, is established, and some virtual control variables are defined. Thus the original coupling plant is divided into some single-input single-output systems and the virtual control variables are willing to be determined by linear active disturbance rejection control method, and the real control variables are easily solved from virtual control variables according to their relationship. The approach is employed to a hypersonic near space vehicle lateral autopilot. The numerical simulations show that the proposed approach has good decoupling effectiveness and guarantees angle command signal tracking accuracy. © 2020, Springer Nature Singapore Pte Ltd.

关键词： Disturbance rejection

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Logarithm Radon-Fourier transform for high speed small target detection with atmospheric resistance effect

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Digital Signal Processing: A Review Journal 2025年 165卷

作者： Sun, Difeng Xu, He Wu, Zutang Li, Jin Wu, Youcao Li, Jianbing State Key Laboratory of Complex Electromagnetic Environmental Effects on Electronics and Information System College of Electronic Science and Technology National University of Defense Technology Changsha410073 China National Key Laboratory of Intense Pulsed Radiation Simulation and Effect Northwest Institute of Nuclear Technology Xi'an710024 China Academy of Military Science of the People's Liberation Army Beijing100071 China

Detecting high-speed, small targets in air is challenging due to their complex non-linear motion model and range migration effects. Traditional finite order polynomial models often fail to account for atmospheric drag accurately. This paper introduces a logarithmic relationship between range and time to model this motion, employing the Logarithmic Radon-Fourier Transform (LRFT) for accurately compensating the envelope and phase migration over extended accumulation periods. It offers both the ergodic search method and the fast implementation method for solving LRFT, along with a theoretical analysis of lobe location and amplitude. simulation results indicate that compared with traditional RFT-based methods, LRFT improves accumulation gain, enhances the main lobe's relative amplitude over sidelobes, and offers better detection performance in noisy environments. It provides more accurate recovery of target motion and improved target distinction capabilities. These benefits over traditional methods are especially evident when the product of the attenuation coefficient α, the initial velocity v0, and the total coherent accumulation time TM exceeds a specific threshold. © 2025 Elsevier Inc.

关键词： Fast Fourier transforms

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Range migration-based Doppler ambiguous integer estimation for moving targets with azimuth spectrum aliasing 6

Range migration-based Doppler ambiguous integer estimation f...

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6th Asia-Pacific Conference on Synthetic Aperture Radar, APSAR 2019

作者： Zhang, Ying Xiong, Wei Dong, Xichao Hu, Cheng Liu, Chengxiang Sun, Yang Science and Technology on Complex Electronic System Simulation Laboratory Space Engineering University Beijing China School of Information and Electronics Beijing Institute of Technology Beijing China

ISBN: (纸本)9781728129129

In some case, the azimuth spectrum bandwidth is larger than the pulse repetition frequency (PRF), leading to a whole azimuth spectrum has been folded into multiple subsegments and aliased. Therefore, the traditional Doppler ambiguous integer estimation method cannot be used directly. In this paper, the influence of Doppler ambiguous integer on residual range migrations' slope is analyzed. Based on the slope, the Doppler ambiguous integer estimation method for moving targets with azimuth spectrum aliasing is given. From the simulation results, the Doppler ambiguous integer can be estimated accurately by proposed method. © 2019 IEEE.

关键词： Synthetic aperture radar

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High-Resolution Range Profile Recognition Method of Vehicle Targets Based on Accelerated T-SNE with Multi-polarization Fusion

High-Resolution Range Profile Recognition Method of Vehicle ...

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IEEE International Conference on Signal and Image Processing (ICSIP)

作者： Hao Wu Dahai Dai Penghui Ji Bo Pang Xuesong Wang State Key Laboratory of Complex Electromagnetic Environment Effects and Electronics and Information System National University of Defense Technology Changsha China College of Electronic Science National University of Defense Technology Changsha China

ISBN: (纸本)9781665446006

Polarization plays an important role in analyzing radar targets. Full polarization information has a better ability to inverse fine structures of the target. However, previous studies of high-resolution range profile (HRRP) mainly neglected effects of polarization. Therefore, a novel radar target recognition algorithm based on accelerated t-Distributed Stochastic Neighbor Embedding(t-SNE) and multi-polarization weighted fusion has been proposed. Firstly, three single polarization channels, odd and even-bounce mechanism HRRP, and full polarization HRRP are described. The accelerated t-SNE method based on Barnes-Hut approximation improves the dimensionality reduction speed of processing HRRPs while maintaining the initial information of each HRRP. Also, it is capable of visualizing different targets. With the weighted fusion of posterior probabilities of multiple support vector machines (SVMs), we are able to realize recognition of targets. Experimental results of vehicle targets based on electromagnetic calculations show that recognition performance of this algorithm is superior to other methods, and it shows strong robustness under the condition of large azimuth angle.

关键词： Support vector machines Dimensionality reduction Image recognition Image resolution Target recognition Fuses Radar

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A Novel Unmanned Aerial Vehicle Recognition Method Based on Bayesian Coherent Point Drift with Full Polarization Information

A Novel Unmanned Aerial Vehicle Recognition Method Based on ...

引用

Progress in Electromagnetic Research Symposium (PIERS)

作者： Hao Wu Dahai Dai Bo Pang Penghui Ji Xuesong Wang State Key Laboratory of Complex Electromagnetic Environment Effects and Electronics and Information System National University of Defense Technology Changsha China College of Electronic Science National University of Defense Technology Changsha China

ISBN: (纸本)9781665409889

The utilization of polarimetric information can expand the understanding of UAVs which effectively interprets shape and structure. In this paper, based on the theory of Bayesian Formulation of Coherent Point Drift (BCPD), a novel radar target recognition algorithm has been proposed. Firstly, the canonical scattering centers are extracted based on the radar imaging results of UAVs which helps to understand the structures and scattering properties. Then we build a novel similarity measurement between the model UAV sample and the test samples which not only reflects the prominent scattering centers but also preserve the overall structure features. UAV electromagnetic data can be acquired which is measured in the anechoic chamber or simulated by electromagnetic software. Finally, we fuse three polarization channels with Bayesian criteria to improve the accuracy of recognition results. The experiment proves that the recognition rate of proposed algorithm with full polarization is better than that with single polarization channel.

关键词： Target recognition Software algorithms Scattering Radar imaging Autonomous aerial vehicles Time measurement Software

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Unmanned Aerial Vehicle Recognition Based on Clustering by Communication with Local Agents and Multiple Polarimetric Features

Unmanned Aerial Vehicle Recognition Based on Clustering by C...

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IEEE International Conference on Signal and Image Processing (ICSIP)

作者： Hao Wu Dahai Dai Bo Pang Zhipeng Wei Xuesong Wang State Key Laboratory of Complex Electromagnetic Environment Effects and Electronics and Information System National University of Defense Technology Changsha China College of Electronic Science National University of Defense Technology Changsha China

ISBN: (纸本)9781665446006

Radar Polarimetric information can effectively expand the understanding of target shape and structure, and have potential of exploring materials and local fine features of targets. In this paper, based on the theory of coherent and incoherent polarimetric decomposition, we extract features of multiple types of unmanned aerial vehicles with full polarization. Then communication with local agents (CLA) method is used to overcome shortcomings of difficulty of obtaining target training samples under real electromagnetic environment conditions. Based on the extracted polarimetric scattering mechanism, we can realize the accurate identification of UAVs without training samples. The validity of the proposed algorithm is verified based on electromagnetic data measured in anechoic chamber and calculated by the software. The experiment proves that the recognition rate of the proposed algorithm is higher than that of conventional algorithms, and it has the ability to characterize the fine structure of unmanned aerial vehicles.

关键词： Training Target recognition Software algorithms Clustering algorithms Radar Feature extraction Autonomous aerial vehicles

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