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Journal of Systems Engineering and Electronics 2024年第1期35卷 43-54页

作者： JIAN Tao HE Jia WANG Bencai LIU Yu XU Congan XIE Zikeng Research institute of Information fusion Naval Aviation UniversityYantai 264001China Air Force Early Warning Academy Wuhan 430019China

Adaptive detection of range-spread targets is considered in the presence of subspace interference plus Gaussian clutter with unknown covariance *** target signal and interference are supposed to lie in two linearly independent subspaces with deterministic but unknown *** on the two-step criteria,two adaptive detectors based on Gradient tests are proposed,in homogeneous and partially homogeneous clutter plus subspace interference,*** of the proposed detectors exhibit theoretically constant false alarm rate property against unknown clutter covariance matrix as well as the power *** results show that,the proposed detectors have better performance than their existing counterparts,especially for mismatches in the signal steering vectors.

关键词： adaptive detection subspace interference constant false alarm rate Gradient test partially homogeneous environment

3D electromagnetic modelling for high-temperature superconducting dynamo flux pumps using T-A formulation

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High Voltage 2024年第2期9卷 367-379页

作者： Luning Hao Fangliang Dong Jintao Hu Qi Wang Haigening Wei Ismail Patel Adil Shah Yuyang Wu Tim Coombs Department of Engineering University of CambridgeCambridgeUK Plasma Science and fusion Center Massachusetts Institute of TechnologyCambridgeMassachusettsUSA

A high-temperature superconducting(HTS)dynamo flux pump can inject DC currents into closed-loop HTS magnets without *** enables the realisation of current-lead-free or even through-wall charging systems for high-field applications such as nuclear magnetic resonance/magnetic resonance imaging(MRI)magnets,fusion reactors and *** have proposed many simulation models to understand the working principle of HTS dynamos,few of which are in 3D because of converging ***,the influences of many key 3D parameters in the HTS dynamo are scarcely *** authors propose an efficient 3D modelling method of the HTS dynamo based on the T-A *** rotating magnets are modelled by a ring-shaped permanent magnet with space-time-variant remanent flux density to avoid moving ***,together with the T-A formulation,makes the 3D model efficient and *** accuracy of the model is verified by the experimental instantaneous and time-integrated dynamic *** this model,the authors present systematic case studies to thoroughly explore the influences of the key parameters of a dynamo flux pump on the dynamic voltage and *** proposed modelling method and results could significantly benefit the design and optimisation of HTS dynamos for high-field magnets.

关键词： formulation magnets pump

Continuous gradient fusion class activation mapping: segmentation of laser-induced damage on large-aperture optics in dark-field images

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High Power Laser Science and Engineering 2024年第1期12卷 30-41页

作者： Yueyue Han Yingyan Huang Hangcheng Dong Fengdong Chen Fa Zeng Zhitao Peng Qihua Zhu Guodong Liu School of Instrumentation Science and Engineering Harbin Institute of TechnologyHarbinChina Research Center of Laser fusion China Academy of Engineering PhysicsMianyangChina

Segmenting dark-field images of laser-induced damage on large-aperture optics in high-power laser facilities is challenged by complicated damage morphology, uneven illumination and stray light interference. Fully supervised semantic segmentation algorithms have achieved state-of-the-art performance but rely on a large number of pixel-level labels, which are time-consuming and labor-consuming to produce. LayerCAM, an advanced weakly supervised semantic segmentation algorithm, can generate pixel-accurate results using only image-level labels, but its scattered and partially underactivated class activation regions degrade segmentation performance. In this paper, we propose a weakly supervised semantic segmentation method, continuous gradient class activation mapping(CAM) and its nonlinear multiscale fusion(continuous gradient fusion CAM). The method redesigns backpropagating gradients and nonlinearly activates multiscale fused heatmaps to generate more fine-grained class activation maps with an appropriate activation degree for different damage site sizes. Experiments on our dataset show that the proposed method can achieve segmentation performance comparable to that of fully supervised algorithms.

关键词： class activation maps laser-induced damage semantic segmentation weakly supervised learning

An improved TDE technique for derivation of 2D turbulence structures based on GPI data in toroidal plasma

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Plasma Science and Technology 2024年第3期26卷 131-137页

作者：王威策程钧石中兵严龙文黄治辉弋开阳吴娜何钰邹千陈熙张文陈建聂林季小全钟武律 Southwestern institute of Physics Chengdu 610299People's Republic of China institute of fusion Science School of Physical Science and TechnologySouthwest Jiaotong UniversityChengdu 610031People's Republic of China

This paper reports an improved time-delay estimation(TDE)technique for the derivation of turbulence structures based on gas-puff imaging *** improved TDE technique,integrating an inverse timing search and hierarchical strategy,offers superior accuracy in calculating turbulent velocity field maps and analyzing blob dynamics,which has the power to obtain the radial profiles of equilibrium poloidal velocity,blob size and its radial velocity,even the fluctuation analysis,such as geodesic acoustic modes and quasi-coherent mode,*** improved technique could provide important 2D information for the study of edge turbulence and blob dynamics,advancing the understanding of edge turbulence physics in fusion plasmas.

关键词： gas-puff imaging TDE method turbulence velocity field map

Non-blind super-resolution reconstruction for laser-induced damage dark-field imaging of optical elements

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Chinese Optics Letters 2024年第4期22卷 36-41页

作者：王倩陈凤东韩越越曾发路程刘国栋 Instrument Science and Technology Harbin Institute of TechnologyHarbin 150001China Research Center of Laser fusion China Academy of Engineering PhysicsMianyang 621900China

The laser-induced damage detection images used in high-power laser facilities have a dark background,few textures with sparse and small-sized damage sites,and slight degradation caused by slight defocus and optical diffraction,which make the image superresolution(SR)reconstruction *** propose a non-blind SR reconstruction method by using an exquisite mixing of high-,intermediate-,and low-frequency information at each stage of pixel reconstruction based on *** simplify the channel attention mechanism and activation function to focus on the useful channels and keep the global information in the *** pay more attention on the damage area in the loss function of our end-toend deep neural *** constructing a high-low resolution image pairs data set,we precisely measure the point spread function(PSF)of a low-resolution imaging system by using a Bernoulli calibration pattern;the influence of different distance and lateral position on PSFs is also considered.A high-resolution camera is used to acquire the ground-truth images,which is used to create a low-resolution image pairs data set by convolving with the measured *** on the data set,our network has achieved better results,which proves the effectiveness of our method.

关键词： laser-induced damage image superresolution image segmentation

A method for active deception jamming discrimination based on frequency response

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Chinese Journal of Aeronautics 2024年第6期37卷 331-347页

作者： Wenbin WEI Ruihui PENG Yunlong DONG Dianxing SUN Le XU Guohong WANG Qingdao Innovation and Development Base of Harbin Engineering University Harbin Engineering University150001China institute of Information fusion Navy Aeronautical UniversityYantai 264001China

There are many types of radar active deception false target jamming that are highly correlated with the real *** the real and false targets under a low Signal-to-Noise Ratio(SNR)is *** solve the above problem,this article proposes a real/false target recognition method based on the features of multi-pulse joint frequency response by analyzing the differences in the scattering characteristics and modeling real target echoes as a synthesis of multi-scattering center ***,in the range-doppler domain,the real and false targets are truncated along the range dimension,and a fast Fourier transform is performed to extract the features of multi-pulse joint frequency ***,a two-channel feature fusion network is designed for real and false target ***,a Multi-Coherent Processing Interval Joint Decision Method(M-CPIJDM)based on temporal information is proposed to improve the recognition *** using the measured data show that the proposed method can well recognize real and false target signals under four jamming backgrounds:distance false target,velocity false target,distance-velocity composite false target,and forwarding dense false target.

关键词： Activedeception false target jamming Multi-scattering center echo Multi-pulse jointfrequency response feature Two-channelfeature fusion network Multi-coherent processing interval jointdecision

Nonlinear dynamics of the reversed shear Alfvén eigenmode in burning plasmas

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Plasma Science and Technology 2024年第5期26卷 1-16页

作者：王涛魏士朝 Sergio BRIGUGLIO Gregorio VLAD Fulvio ZONCA 仇志勇 institute for fusion Theory and Simulation and School of Physics Zhejiang UniversityHangzhou 310027People’s Republic of China Center for Nonlinear Plasma Science ENEA C.R.FrascatiFrascati 00044Italy fusion and Nuclear Safety Department ENEA C.R.FrascatiFrascati 00044Italy

In a tokamak fusion reactor operated at steady state,the equilibrium magnetic field is likely to have reversed shear in the core region,as the noninductive bootstrap current profile generally peaks *** reversed shear Alfvén eigenmode(RSAE)as a unique branch of the shear Alfvén wave in this equilibrium,can exist with a broad spectrum in wavenumber and frequency,and be resonantly driven unstable by energetic particles(EP).After briefly discussing the RSAE linear properties in burning plasma condition,we review several key topics of the nonlinear dynamics for the RSAE through both wave-EP resonance and wave-wave coupling channels,and illustrate their potentially important role in reactor-scale fusion *** means of simplified hybrid MHD-kinetic simulations,the RSAEs are shown to have typically broad phase space resonance structure with both circulating and trapped EP,as results of weak/vanishing magnetic shear and relatively low *** the route of wave-EP nonlinearity,the dominant saturation mechanism is mainly due to the transported resonant EP radially decoupling with the localized RSAE mode structure,and the resultant EP transport generally has a convective *** saturated RSAEs also undergo various nonlinear couplings with other collective *** typical routes as parametric decay and modulational instability are studied using nonlinear gyrokinetic theory,and applied to the scenario of spontaneous excitation by a finite amplitude pump *** RSAEs could naturally couple and induce the spectral energy cascade into a low frequency Alfvénic mode,which may effectively transfer the EP energy to fuel ions via collisionless Landau ***,zero frequency zonal field structure could be spontaneously excited by modulation of the pump RSAE envelope,and may also lead to saturation of the pump RSAE by both scattering into stable domain and local distortion of the continuum structure.

关键词： reversed shear Alfvén eigenmode energetic particle nonlinear gyrokinetic theory saturation burning plasma

General Mean-Field BDSDEs with Continuous and Stochastic Linear Growth Coefficients

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Journal of Systems Science & Complexity 2024年第5期37卷 1887-1906页

作者： WANG Jinghan SHI Yufeng ZHAO Nana institute for Financial studies Shandong University Zhiyuan School of Liberal Arts Beijing Institute of Petrochemical Technology

In this paper, the authors study a class of general mean-field BDSDEs whose coefficients satisfy some stochastic conditions. Specifically, the authors prove the existence and uniqueness theorem of solution under stochastic Lipschitz condition and obtain the related comparison theorem. Besides,the authors further relax the conditions and deduce the existence theorem of solutions under stochastic linear growth and continuous conditions, and the authors also prove the associated comparison ***, an asset pricing problem is discussed, which demonstrates the application of the general mean-field BDSDEs in finance.

关键词： Backward doubly stochastic differential equations comparison theorem mean-field stochastic conditions Wasserstein metric

Investigation on Strengthening Mechanism of China Low-Activation Ferrite Steel upon Thermo-Mechanical Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 373-387页

作者： Dongtian Yang Liangyin Xiong Hongbin Liao Guoping Yang Xiaoyu Wang Shi Liu institute of Metal Research Chinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Center for fusion Science Southwestern Institute of PhysicsChengdu610041China

The objective of this study was to investigate the influence of strengthening mechanisms on the high-temperature mechanical properties of China low-activation ferrite(CLF-1)steel,which underwent thermodynamic design and thermo-mechanical treatment(TMT).The microstructure characterization in the normalized and tempered condition and the TMT condition was carried out using optical microscopy,X-ray diffractometer,and scanning electron microscopy with electron backscatter ***-resolution transmission electron microscopy was employed to determine the crystallographic structures of precipitated *** results indicated that the addition of Ti led to an increase in the allocation of C in MC phase and an enhancement in the content of MC *** to CLF-P steel in the normalized and tempered condition,a 1.5-fold increase in dislocation density and an order of magnitude improvement in MX phase density were achieved after *** formation of high-density nano-scale MC phases during TMT played a significant role in precipitation strengthening due to their favorable coherent relationship with the matrix and low interfacial free *** excellent high-temperature mechanical properties observed in CLF-P steel after TMT can be attributed to the combined effects of precipitation strengthening,dislocation strengthening,and lath strengthening.

关键词： China low-activation ferrite(CLF-1)steel Thermo-mechanical treatment MC phase Crystallographic structure Strengthening mechanism

A path planning algorithm for a crop monitoring fixed-wing unmanned aerial system

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Science China(Information Sciences) 2024年第08期67卷 5-23页

作者： Longhao QIAN Yi Lok LO Hugh Hong-tao LIU institute of Aerospace studies University of Toronto Department of Mechanical Engineering The University of Hong Kong

With the growing demand for automation in agriculture, industries increasingly rely on drones to perform crop monitoring and surveillance. In this regard, fixed-wing unmanned aerial systems(UASs)are viable platforms for scanning a large crop field, given their payload capacity and range. To achieve maximum coverage without landing for battery replacement, an algorithm for producing a minimal required energy survey path is essential. Hence, an energy-aware coverage path planning algorithm is proposed *** constraints for a fixed-wing UAS to fly at low altitudes while achieving full coverage of the crop field are first analyzed. Then, the full path is decomposed into straight-line and U-turn primitives. Finally, an algorithm to calculate a combination of straight-line segments and U-turns is proposed to obtain the path with minimum required energy consumption. The genetic algorithm is used to efficiently determine the order of the straight-line paths to traverse. Case studies show that the proposed algorithm can produce planning results for a convex-polygon-shaped crop field.

关键词： aerial survey energy minimization fixed-wing UAS genetic algorithm path planning

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