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基于远场同轴全息的激光M^(2)因子测量技术

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光学学报 2023年第14期43卷 49-56页

作者：李俊博刘斯靓韩志刚李方欣杨振营芮九多王琦朱日宏南京理工大学电子工程与光电技术学院江苏南京210094 南京理工大学先进固体激光工信部重点实验室江苏南京210094

激光光束质量M^(2)因子的动态测量对激光器的设计、制造与应用均具有重要意义。本文提出了一种基于远场同轴全息的光纤激光器光束质量M^(2)因子动态测量方法。通过偏振移相同轴全息技术直接获取待测激光的远场复振幅信息,利用角谱传输... 详细信息

激光光束质量M^(2)因子的动态测量对激光器的设计、制造与应用均具有重要意义。本文提出了一种基于远场同轴全息的光纤激光器光束质量M^(2)因子动态测量方法。通过偏振移相同轴全息技术直接获取待测激光的远场复振幅信息,利用角谱传输及透镜变换理论求解激光在自由空间中的光场强度分布,从而实现M^(2)因子的动态测量。实验搭建了远场同轴全息装置,测量了不同纤芯直径光纤在632.8 nm波长下的激光光束质量,其结果与BEAM SQUARED商用光束质量仪的测量结果一致。本文所提方法仅需0.02 s即可实现光纤激光的M^(2)因子测量,比商用光束质量仪的测量速度提高了两个数量级以上。此外,本装置结构紧凑,能够避免透镜引入的装调及加工误差。

关键词：光纤光学与光通信光束质量M^(2)因子同轴移相干涉角谱传输透镜变换

A fast and high-accurate commutation failure identification method for LCC-HVDC system

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High Voltage 2024年第3期9卷 721-732页

作者： Jing Feng Zhijie liu Kejun li Bingkun li Jiachen li liangzi li School of Electrical Engineering Shandong UniversityJinanShandongChina

Commutation failure(CF)is one of the most common issues in line-commuted converter-based high voltage direct current systems(LCC-HVDC),leading to critical power system security and stability *** and rapid identification of CF is crucial to prevent subsequent CF in HVDC ***,the existing CF identi-fication methods are lack of the required accuracy and *** relationship between bridge arm current,commutation voltage,and trigger pulse based on the commutation progress mechanism after the AC fault is analysed in this paper.A novel CF identification method is presented,which utilises the CF identification factor,enabling fast and high-accurate identification without relying on the value of the extinction *** pro-posed method offers a simpler and more efficient implementation in engineering ***,the effectiveness of the proposed method is verified in both the standard In-ternational Council on Large Electric systems HVDC model and the Hardware in Loop test using practical project *** results demonstrate that the proposed method can accurately and fast identify CF.

关键词： system method LCC

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CuY型分子筛制备及吸附脱硫影响因素研究

离子交换与吸附 2012年第1期28卷 18-25页

作者：黎俊波刘习文曹灿灿郭嘉潘志权绿色化工过程教育部重点实验室武汉工程大学化工与制药学院

通过液相离子交换法制备CuY型分子筛,并利用正交实验得到了制备过程中交换时间、交换温度、铜离子浓度的最佳条件。系统研究了CuY分子筛的焙烧温度、吸附时间、吸附温度对其吸附脱除模拟油中二苯并噻吩(DBT)的影响。采用XRD、ICP及BET... 详细信息

通过液相离子交换法制备CuY型分子筛,并利用正交实验得到了制备过程中交换时间、交换温度、铜离子浓度的最佳条件。系统研究了CuY分子筛的焙烧温度、吸附时间、吸附温度对其吸附脱除模拟油中二苯并噻吩(DBT)的影响。采用XRD、ICP及BET比表面积分别对不同CuY分子筛的骨架结构及阳离子负载量进行了研究。结果表明,二次交换后,分子筛已达到交换平衡,最佳焙烧温度为450℃,温度过高会破坏分子筛的骨架结构;分子筛上的吸附水对其吸附脱除二苯并噻吩的能力有较大的影响。

关键词：吸附脱硫 CuY分子筛静态法二苯并噻吩

An internal ballistic model of electromagnetic railgun based on PFN coupled with multi-physical field and experimental validation

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Defence Technology（防务技术） 2024年第2期32卷 254-261页

作者： Benfeng Gu Haiyuan li Baoming li National Key Laboratory of Transient Physics Nanjing University of Science and TechnologyNanjing 210094China

To accelerate the practicality of electromagnetic railguns,it is necessary to use a combination of threedimensional numerical simulation and experiments to study the mechanism of bore *** this paper,a three-dimensional numerical model of the augmented railgun with four parallel unconventional rails is introduced to simulate the internal ballistic process and realize the multi-physics field coupling calculation of the rail gun,and a test experiment of a medium-caliber electromagnetic launcher powered by pulse formation network(PFN)is carried *** test methods such as spectrometer,fiber grating and high-speed camera are used to test several parameters such as muzzle initial velocity,transient magnetic field strength and stress-strain of *** the simulation results and experimental data,the damage condition of the contact surface is analyzed.

关键词： Internal ballistic modeling Electromagnetic rail gun Multi-physics field coupling Experimental validation PFN

An efficient approach for the equivalent linearization of frame structures with plastic hinges under nonstationary seismic excitations

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 677-690页

作者： Huang Huan li Yingxiong li Yuyu College of Water Conservancy and Civil Engineering South China Agricultural UniversityGuangzhou 510642China Institute of Smart City and Intelligent Transportation Southwest Jiaotong UniversityChengdu 611756China

An efficient approach is proposed for the equivalent linearization of frame structures with plastic hinges under nonstationary seismic *** concentrated plastic hinges,described by the Bouc-Wen model,are assumed to occur at the two ends of a linear-elastic beam *** auxiliary differential equations governing the plastic rotational displacements and their corresponding hysteretic displacements are replaced with linearized differential ***,the two sets of equations of motion for the original nonlinear system can be reduced to an expanded-order equivalent linearized equation of motion for equivalent linear *** solve the equation of motion for equivalent linear systems,the nonstationary random vibration analysis is carried out based on the explicit time-domain method with high ***,the proposed treatment method for initial values of equivalent parameters is investigated in conjunction with parallel computing technology,which provides a new way of obtaining the equivalent linear systems at different time *** on the explicit time-domain method,the key responses of interest of the converged equivalent linear system can be calculated through dimension reduction analysis with high *** examples indicate that the proposed approach has high computational efficiency,and shows good applicability to weak nonlinear and medium-intensity nonlinear systems.

关键词： nonstationary random vibration plastic hinge equivalent linearization method explicit time-domain method parallel computation

Study on the effective elastic performance of composites containing decagonal symmetric two-dimensional quasicrystal coatings

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Applied Mathematics and Mechanics(English Edition) 2024年第9期45卷 1655-1664页

作者： Yurun WU Lu li lianhe li School of Mathematics and Science Inner Mongolia Normal UniversityHohhot 010022China Inner Mongolia Applied mathematics Center Hohhot 010022China Key Laboratory of Infinite Dimensional Hamiltonian System and Its Algorithm Application Ministry of EducationHohhot 010022China

On account of the Mori-Tanaka approach,the effective elastic performance of composites containing decagonal symmetric two-dimensional(2D)quasicrystal(QC)coatings is *** expressions for the effective elastic constants of rare-earth QC reinforced magnesium-based composites are *** discussion is presented on the effects of the volume fraction of the inclusions,the aspect ratio of the inclusions,the coating thickness,and the coating material parameters on the effective elastic constants of the *** results indicate that considering the coating increases the effective elastic constants of the composites to some extent.

关键词： Mori-Tanaka approach coated inclusion decagonal symmetric twodimensional(2D)quasicrystal(QC)

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横向超声多普勒技术的应用

中国生物医学工程学报 2000年第1期19卷 84-92页

作者：万明习李俊博钱明巩欣洲西安交通大学生物医学工程系西安710049

当超声波束与流速垂直时 ,获得的横向多普勒功率谱宽度与采样单元内最大流速成正比。横向超声多普勒技术在流速测量时避免了采样单元内流速梯度造成的模糊 ,弥补了常规多普勒技术在大角度流速测量时存在盲区的缺陷 ,克服了以往B超成像... 详细信息

当超声波束与流速垂直时 ,获得的横向多普勒功率谱宽度与采样单元内最大流速成正比。横向超声多普勒技术在流速测量时避免了采样单元内流速梯度造成的模糊 ,弥补了常规多普勒技术在大角度流速测量时存在盲区的缺陷 ,克服了以往B超成像与多普勒流速测量对声束要求的矛盾。本文提出了利用横向多普勒技术估计血管剪切率、进行无模糊湍流测量以及最大血流速度校正的新方法 ,设计了多通道横向多普勒系统 ,实验结果证实了横向多普勒技术在血流动力学领域应用的有效性。本文从应用方面扩展了横向多普勒技术的研究领域。

关键词：横向超声多普勒剪切率湍流超声波诊断

Topology Optimization Method for Microscale Structures Described with Integral Nonlocal Theory

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Acta Mechanica Solida Sinica 2024年第1期37卷 63-71页

作者： Jiayu li Quhao li Shutian liu State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

The integration of additive manufacturing and topology optimization makes it possible to fabricate complex configurations,especially for microscale structures,which can guarantee the realization of high-performance structural ***,topology results often contain microstructures(several multicellular scales)similar to the characteristic length of local macrostructures,leading to errors in structural performance analysis based on classical ***,it is necessary to consider the size effect in topology *** this paper,we establish a novel topology optimization model utilizing the integral nonlocal theory to account for the size *** approach consists of an integral constitutive model that incorporates a kernel function,enabling the description of stress at a specific point in relation to strain in a distant *** optimization structures based on nonlocal theory are presented for some benchmark examples,and the results are compared with those based on classical medium *** material layout exhibits significant differences between the two approaches,highlighting the necessity of topology optimization based on nonlocal theory and the effectiveness of the proposed method.

关键词： Topology optimization Microstructures Integral nonlocal theory Size effect

Al/Hf ratio-dependent mechanisms of microstructure and mechanical property of nearly fully dense Al—Hf reactive material

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Defence Technology（防务技术） 2024年第1期31卷 230-241页

作者： Junbao li Weibing li Xiaoming Wang ZNDY of Ministerial Key Laboratory Nanjing University of Science and TechnologyNanjing 210094China

This study proposed three types of Al—Hf reactive materials with particle size ratios(a),which were almost completely dense(porosity of<5.40%)owing to their preparation using hot-pressing *** characteristics and phas... 详细信息

This study proposed three types of Al—Hf reactive materials with particle size ratios(a),which were almost completely dense(porosity oflinearly with increasing strain rate.ε.It is found that the plastic deformation of the material increased with increasing strain *** a increased from 0.1 to 1,the flow stress gradually *** failure of the material was dominated by ductile fracture with a large Al phase plastic deformation band for lower a,while brittle fracture with crushed Hf particles occurred at higher ***,a constitutive model based on BP neural network was proposed to describe the stress-strain relationships of the materials,with an average relative error of 2.22%.

关键词： Reactive material Particle size Split Hopkinson pressure bar test Stressestrain relationship Impact failure BP neural network