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Uneven Evolution of Microstructure,Magnetic Properties and Coercivity Mechanism of Mo-Substituted Nd-Ce-Fe-B Alloys

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Acta Metallurgica Sinica(English Letters) 2021年第4期34卷 590-596页

作者： li-li Zhang jie Song Sajjad Ur Rehman Jia-jie li Lei Wang Mu-Nan Yang Ren-Hui liu Qing-zheng Jiang zhen-Chen Zhong Jiangxi Key Laboratory for Rare Earth Magnetic Materials and Devices/Institute for Rare Earth Magnetic Materials and Devices Jiangxi University of Science and TechnologyGanzhou341000China Fujian Changting Golden Gragon Rare-Earth Co. LtdChangting366300China

The purpose of this paper is to study the influence of Mo addition on the phase morphologies,microstructures and magnetic properties of the designated *** is found out that the coercivity H_(cj) increases unevenly from 12.2 kOe for(Nd_(0.8)Ce_(0.2))_(13)Fe_(82)B_(5) to the maximum value of 13.3 kOe for(Nd_(0.8)Ce_(0.2))_(13)Fe_(80)B_(5)Mo_(2).The transmission electron microscopy images demonstrate that the grain size decreases with the addition of Mo,which indicates that Mo has grain refinement *** correlative analysis gives rise to the conclusion that the coercivity mechanism of the investigated alloys is dominated by pinning *** in all,the enhancement of the magnetic properties is mainly attributed to the synergistic impact of grain refinement,pinning effects and the micro structural *** research may shed light on the potential development and application of rare earth-based counterpart magnets.

关键词： Mo-doped Nd-Ce-Fe-B alloy Magnetic properties Melt-spun ribbons Microstructure Coercivity mechanism

A zero-sum hybrid stochastic differential game with impulse controls

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Science China(Information Sciences) 2024年第11期67卷 285-299页

作者： Siyu LV zhen WU jie XIONG School of Mathematics Southeast University School of Mathematics Shandong University Department of Mathematics and SUSTech International Center for Mathematics Southern University of Science and Technology

In this paper, we study a zero-sum stochastic differential game with the following salient features:(i) the system state is dictated by a hybrid diffusion,(ii) both players use impulse controls, and(iii) the game takes place on an infinite time horizon. First, the dynamic programming principle for the problem is ***, the lower and upper value functions of the game are characterized as the unique viscosity solution of the associated Hamilton-Jacobi-Bellman-Isaacs(HJBI) equation, which turns out to be a coupled system of variational inequalities with bilateral obstacles. Moreover, a verification theorem as a sufficient condition to identify a Nash equilibrium is established. The Nash equilibrium strategies for the two players, indicating when and how it is optimal to intervene, are given in terms of the obstacle part of the HJBI equation.

关键词： stochastic differential game Markov chain impulse control HJBI equation viscosity solution verification theorem

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Laser manufacturing of spatial resolution approaching quantum limit

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light(Science & Applications) 2024年第3期13卷 421-428页

作者： Xiao-jie Wang Hong-Hua Fang zhen-Ze li Dan Wang Hong-Bo Sun State Key Laboratory of Precision Measurement Technology and Instruments Department of Precision InstrumentTsinghua UniversityBeijing 100084China State Key Laboratory of Integrated Optoelectronics College of Electronic Science and EngineeringJilin University2699 Qianjin StreetChangchun 130012China

Atomic and close-to-atom scale manufacturing is a promising avenue toward single-photon emitters,single-electron transistors,single-atom memory,and quantum-bit devices for future communication,computation,and sensing *** manufacturing is outstanding to this end for ease of beam manipulation,batch production,and no requirement for *** is,however,suffering from optical diffraction ***,we report a spatial resolution improved to the quantum limit by exploiting a threshold tracing and lock-in method,whereby the two-order gap between atomic point defect complexes and optical diffraction limit is surpassed,and a feature size oflications.

关键词： quantum limit resolution

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基于耦合映像格子的明文关联图像加密方案

聊城大学学报（自然科学版） 2025年第1期38卷 14-22页

作者：张爽李震贵阳人文科技学院大数据与信息工程学院贵州贵阳550025 贵州大学大数据与信息工程学院贵州贵阳550025

明文敏感性是图像加密系统重要的性能指标,用来评估加密系统抵抗差分攻击能力,而明文关联是提高明文敏感性的主要手段。针对明文关联问题,提出一种基于耦合映像格子(CML)的明文关联图像加密方案。该方案首先构建明文关联内部密钥生成模... 详细信息

明文敏感性是图像加密系统重要的性能指标,用来评估加密系统抵抗差分攻击能力,而明文关联是提高明文敏感性的主要手段。针对明文关联问题,提出一种基于耦合映像格子(CML)的明文关联图像加密方案。该方案首先构建明文关联内部密钥生成模型生成明文关联密钥流,然后在密钥流控制下完成加密操作。加密算法首先采用一轮Zigzag置乱和XOR掩码,然后进行Zigzag-CBC扩散,最后再进行一轮Zigzag置乱和XOR掩码输出密文图像。随后采用直方图、相关性分析、差分攻击、信息熵等方法对密码系统进行安全性能分析,实验结果表明,基于耦合映像格子的明文关联图像加密方案具有良好的安全性能,可以满足绝大多数应用场景下的图像加密需求。

关键词：图像加密安全性分析耦合映像格子

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Full-parameter constrained parsimonious subspace identification with steady-state information for DC–DC converters

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Control Theory and Technology 2024年第2期22卷 173-183页

作者： jie Hou zhen Yang Taifu li Huiming Wang Jincheng Jiang Xiaolei Chen College of Automation Chongqing University of Posts and TelecommunicationsChongqing400065China School of Electrical and Information Engineering Chongqing University of Science and TechnologyChongqing401331China

A full-parameter constrained parsimonious subspace identification method that incorporates the steady-state a priori infor-mation of the system is proposed to model the DC-DC converters.A parsimonious model with fewer parameters is used to represent the system,and then an optimal weighted methods is used to estimate the system parameters matrices by taking into account both dynamical data and steady-state *** with traditional data-driven methods for DC-DC convert-ers,the subspace-based method can simultaneously estimate model structure and parameter with appropriate computational ***,compared with the traditional full-parameter constrained subspace approach,the proposed algorithm can accurately estimate the system parameters with a smaller *** experimental results on a DC-DC synchronous buck converter verify the effectiveness and superiority of the proposed method.

关键词： System identification Constrained identification DC-DC converters Subspace identification

EBSD parameter assessment and constitutive models of crept HR3C austenitic steel

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Journal of Iron and Steel Research International 2023年第4期30卷 772-781页

作者： jie Zhang zheng-fei Hu zhen Zhang Shanghai Key Laboratory for R&D and Application of Metallic Functional Materials School of Materials Science and EngineeringTongji UniversityShanghai 201804China School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing 211167JiangsuChina

Creep damage and evolution of HR3C steel at 650℃ were investigated using electron backscatter diffraction(EBSD),and EBSD-based parameter assessments were *** analyses show that the grain size is almost unchanged and no obvious texture formed after creep at different creep *** lowest proportion of low Σ coincidence site lattice grain boundaries under 150 MPa implies that the primary twin structures are preserved under the low stress level,while some twin structures evolved into general grain boundaries at the high creep *** main damage features of microcracks and cavities can be seen along the grain boundaries:the former emerged at higher stress levels,while the latter appeared at the lower stress level,and both were shown under medium *** contrast shows that the most severe creep damage is present at 170 *** implies that the creep mechanism differs distinctly under different stress levels,and the transition point is around 170 *** average misorientation is better to describe the local plastic deformation related to the strain distribution while grain reference orientation deviation describes the inhomogeneous strain *** lifetime prediction models including the isothermal method,Larson-Miller parameter method and Monkman–Grant relation were evaluated by the experimental data and literature data,and they are valid for predicting creep behavior.

关键词： Austenitic heat-resistant steel Creep damage Electron backscatter diffraction Creep constitutive model Creep lifetime prediction

A PDEM-based perspective to engineering reliability: From structures to lifeline networks

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Frontiers of Structural and Civil Engineering 2020年第5期14卷 1056-1065页

作者： jie li School of Civil Engineering&State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China

Research of reliability of engineering structures has experienced a developing history for more than 90 ***,the problem of how to resolve the global reliability of structural systems still remains open,especially the problem of the combinatorial explosion and the challenge of correlation between failure *** from the research of probability density evolution theory in recent years,the physics-based system reliability researches open a new way for bypassing this *** present paper introduces the theoretical foundation of probability density evolution method in view of a broad background,whereby a probability density evolution equation for probability dissipative system is *** conjunction of physical equations and structural failure criteria,a general engineering reliability analysis frame is then *** illustrative purposes,several cases are studied which prove the value of the proposed engineering reliability analysis method.

关键词： PDEM reliability structure lifeline networks

THUBrachy:fast Monte Carlo dose calculation tool accelerated by heterogeneous hardware for high-dose-rate brachytherapy

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Nuclear Science and Techniques 2021年第3期32卷 107-119页

作者： An-Kang Hu Rui Qiu Huan liu zhen Wu Chun-Yan li Hui Zhang Jun-li li Rui-jie Yang Department of Engineering Physics Tsinghua UniversityBeijing 100084China Key Laboratory of Particle and Radiation Imaging Tsinghua UniversityMinistry of EducationBeijing 100084China Nuctech Company limited Beijing 100084China Department of Radiation Oncology Peking University Third HospitalBeijing 100191China

The Monte Carlo(MC)simulation is regarded as the gold standard for dose calculation in brachytherapy,but it consumes a large amount of computing *** development of heterogeneous computing makes it possible to substantially accelerate calculations with hardware ***,this study develops a fast MC tool,called THUBrachy,which can be accelerated by several types of hardware *** can simulate photons with energy less than 3 MeV and considers all photon interactions in the energy *** was benchmarked against the American Association of Physicists in Medicine Task Group No.43 Report using a water phantom and validated with Geant4 using a clinical case.A performance test was conducted using the clinical case,showing that a multicore central processing unit,Intel Xeon Phi,and graphics processing unit(GPU)can efficiently accelerate the ***-accelerated THUBrachy is the fastest version,which is 200 times faster than the serial version and approximately 500 times faster than *** proposed tool shows great potential for fast and accurate dose calculations in clinical applications.

关键词： High-dose-rate brachytherapy Monte Carlo Heterogeneous computing Hardware accelerators

Origin of soft-sediment deformation structures in Nihewan Basin

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Journal of Palaeogeography 2022年第3期11卷 332-359页

作者： De-Chen Su Ai-Ping Sun Zhao-li li Song-Yong Chen zhen-jie Wu Key Laboratory of Deep-Earth Dynamics of Ministry of Natural Resources Institute of GeologyChinese Academy of Geological SciencesBeijing100037China Jiangsu Donghai Continental Deep Hole Crustal Activity National Observation and Research Station China

The Nihewan Basin is a rift basin at the junction of northern Shanxi Province and northwestern Hebei Province in north *** basin is known for its rich paleontological fossils and ancient human *** are also abundant soft-sediment deformation structures(SSDS)in the thick lacustrine ***,most SSDS have been interpreted as ice-edge features or ignored ***,the authors have carried out several field surveys in the Nihewan Basin and found that many SSDS are sandwiched between normal lacustrine strata at multiple *** the excavation pit at the 10th Locality of Maliang Site(ML10),10 horizontal SSDS layers and two vertically developed geological features have been *** on genesis analysis and related criteria,these features are divided into two categories:cryoturbation-triggered SSDS and earthquake-triggered *** them,a special type of ancient ice-wedge pseudomorph(SSDS-8)of ML10 is recognized in the basin for the first *** other 9 horizontal SSDS are mainly caused by earthquake-triggered liquefaction and *** can be further divided into 14 seismic event *** findings indicate that the tectonic activity in the Nihewan Basin is very strong and frequent,and there were cold periods in the geological history of the *** the same time,the SSDS with distinct morphological characteristics and stable horizontal distribution in the basin can be used as an important indicator of stratigraphic correlation.

关键词： Nihewan Basin Soft-sediment deformation structures(SSDS) Paleoearthquake Freezing-and-thawing Ice-wedge Palaeolithic site