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低反射电阻阵列加载单锥TEM室研制与测试

高电压技术 2024年第3期50卷 1340-1347页

作者：王晓嘉周恒张守龙蒋廷勇孙一飞刘真中国人民解放军63660部队洛阳471000

为了减小单锥末端反射、拓展镜面单锥TEM室时间窗,基于母线长0.9 m单锥TEM室计算了不同电阻加载条件下的馈电端口电压反射系数,通过搭建电阻阵列加载单锥TEM室实验平台对仿真结果进行了验证,在此基础上,通过改进锥体吊装结构、调整镜面... 详细信息

为了减小单锥末端反射、拓展镜面单锥TEM室时间窗,基于母线长0.9 m单锥TEM室计算了不同电阻加载条件下的馈电端口电压反射系数,通过搭建电阻阵列加载单锥TEM室实验平台对仿真结果进行了验证,在此基础上,通过改进锥体吊装结构、调整镜面板与吸波材料之间距离等方式对单锥结构进行了优化,设计并研制了国内首个低反射单锥微波暗室。研究结果表明,在单锥锥体末端与镜面板边缘之间加载阻抗匹配回路,解决了单锥TEM室低频吸收问题,减小了单锥TEM室末端反射,突破了由母线长度决定的时间窗限制,拓展了单锥TEM室的适用范围,实现了HEMP、LEMP等瞬态电磁脉冲传感器幅值灵敏度和波形保真度的全校准。

关键词：电阻加载时间窗单锥TEM室传感器校准和标定低反射标准场微波暗室

Breakage and shape analysis of ballast aggregates with different size distributions

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Particuology 2017年第6期15卷 84-92页

作者： yifei sun Changjie Zheng Key Laboratory ofMinistryof Education for Geomechanics and Embankment Engineering College of Civil and Transportation Engineering Hohai University Nanjing 210098 China School of Civil Mining and Environmental Engineering University ofWollongong Wollongong NSW2522 Australia Key Laboratory of New Technology for Consgruction of Cities in Mountain Area Ministry of Education School of Civil Engineering Chongqing University Chongqing 400045 China

Particle breakage usually alters the size and shape of ballast aggregates, which significantly influences the long-term performance of rail tracks. This study reports an investigation on the breakage and shape characteristics of ballast aggregates subjected to monotonic and cyclic triaxial tests with two different load frequencies. The results show that particle breakage is not only influenced by the particle size distribution but also by the relative density. Breakage indices defined by breakage potential and grading entropy fail to characterize the breakage extent of ballast with multiple initial particle size distributions, while the Marsal breakage index exhibits a general decrease with increasing coefficient of uniformity for ballast with similar relative densities. Higher breakage extent is observed in ballast subjected to a higher load frequency. Particle shape varies with load frequency because of breakage. A slightly higher value of each shape index is observed for ballast subjected to a higher load frequency, implying that ballast aggregates become increasingly regular with the increase of load frequency,

关键词： Breakage Breakage potentia Grading entropy Particle shape Ballast

基于改进鸡群优化算法运动学与改进鸡群优化-Elman神经网络非运动学的机器人误差标定

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Spatial Strategy for Quality Labor in Rural Development——A Case Study of Jiangsu Province, China

信息与控制 2024年第3期53卷 315-328页

作者：江小辉孙翼飞郭维诚侯春杰任斐上海理工大学机械工程学院上海航天设备制造总厂有限公司

针对工业机器人末端定位误差标定问题，本文从机器人运动学与非运动学两个方面对机器人进行定位误差标定。针对机器人运动学方面，建立了运动学误差模型并提出一种改进CSO(chicken swarm optimization)算法对机器人进行几何参数误差辨... 详细信息

针对工业机器人末端定位误差标定问题，本文从机器人运动学与非运动学两个方面对机器人进行定位误差标定。针对机器人运动学方面，建立了运动学误差模型并提出一种改进CSO(chicken swarm optimization)算法对机器人进行几何参数误差辨识，通过对比LM(Levenberg-Marquardt)迭代算法与PSO(particle swarm optimization)算法验证本文所提出算法的效果，以IRB1200机器人为实验对象，通过APIT3激光跟踪仪采集误差数据，搭建了机器人误差标定实验平台进行实验。经实验测量，机器人末端平均定位误差由2.76 mm下降至1.45 mm,提升了47.5%;同时针对机器人非运动学方面，使用在运动学误差标定中提出的改进CSO算法优化了Elman神经网络的初始阈值与权重，并使用初始参数优化的Elman神经网络建立机器人末端位置误差与机器人关节角之间的映射关系，以预测训练完成的机器人立方体空间内的机器人位置误差，并对比了普通Elman神经网络的预测效果。经实验测量，机器人末端平均定位精度较标定前提升34.9%,验证了本文所提出神经网络的拟合预测效果。

关键词：工业机器人参数辨识 Elman神经网络鸡群优化算法

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Chinese Geographical Science 2007年第2期17卷 117-126页

作者： sun yifei WANG Hongyang Department of Geography California State University Northridge Los Angeles 91330 USA Department of Urban and Resources Sciences Nanjing University Nanjing 210093 China

This study examines the issue of high-quality labor in rural enterprises of China. It develops a spatial strategy which consists of two dimensions: geographical space and administrative space. Different combinations of these two dimensions form a variety of approaches such as local internalization, local externalization, regional/national inter- nalization, and regional/national externalization. In the local internalization approach, rural enterprises hire such high-quality labor and ask them to work on site, while in the local externalization approach, rural enterprises seek help from employees working in other local enterprises. In the regional/national internalization approach, rural enterprises set up research and development centers in big cities to take advantages of the high-quality labor pool there. Finally in the regional/national externalization approach, rural enterprises hire people from big cities on temporary contracts. Three approaches, hiring retired technical workers, shuttling between the rural site and country seats, and setting up R&D centers in big cities are demonstrated through cases in Zhangjiagang, a leading county-level city in the southern Jiangsu Province. It is argued that rural enterprises need to broaden their perspectives of administrative space and geographical space and think creatively to deal with the shortage of quality labor in rural settings.

关键词： skilled labor quality labor rural development spatial strategy China

TriMule机器人并联机构运动学分析与仿真

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机械科学与技术 2024年第10期43卷 1664-1671页

作者：江小辉孙翼飞郭维诚侯春杰上海理工大学机械工程学院上海200093 上海航天设备制造总厂有限公司上海200240

针对并联机构运动学模型求解困难的问题,以TriMule并联机构为研究对象对其正向运动学与逆向运动学进行了分析与仿真,并通过样机平台的加工工艺参数评价了运动学算法的正确性与稳定性。根据TriMule机器人机构特点,基于矢量法与连杆长度... 详细信息

针对并联机构运动学模型求解困难的问题,以TriMule并联机构为研究对象对其正向运动学与逆向运动学进行了分析与仿真,并通过样机平台的加工工艺参数评价了运动学算法的正确性与稳定性。根据TriMule机器人机构特点,基于矢量法与连杆长度差迭代法建立机器人并联机构的运动学逆解及正解模型,推导机器人驱动支链长度与动定平台位姿关系;在机器人运动空间中选取样本位姿,应用MATLAB对所建立TriMule机器人并联机构运动学模型进行仿真验证,结果表明运动学模型求解算法正确稳定。最后搭建TriMule机器人搅拌摩擦焊实验平台验证运动学算法控制稳定性。

关键词： TriMule机器人运动学正解运动学逆解仿真验证

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Dilation and breakage dissipation of granular soils subjected to monotonic loading

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Acta Mechanica Sinica 2016年第6期32卷 1065-1074页

作者： yifei sun Yang Xiao Hua Ji Faculty of Engineering and Information Sciences University of Wollongong School of Civil and Transportation Engineering Hohai University College of Civil Engineering Chongqing University

Dilation and breakage energy dissipation of four different granular soils are investigated by using an energy balance equation. Due to particle breakage, the dilation curve does not necessarily pass through the origin of coordinates. Breakage energy dissipation is found to increase significantly at the initial loading stage and then gradually become stabilised. The incremental dissipation ratio between breakage energy and plastic work exhibits almost independence of the confining pressure. Accordingly, a plastic flow rule considering the effect of particle breakage is suggested. The critical state friction angle is found to be a combination of the basic friction between particles and the friction contributed by particle breakage.

关键词： Dilation Particle breakage Granular soil Energy dissipation

Effect of integrating memory on the performance of the fractional plasticity model for geomaterials

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Acta Mechanica Sinica 2018年第5期34卷 896-901页

作者： yifei sun Yufeng Gao Shunxiang Song Key Laboratory of Ministry of Education for Geomechanics and Embankment Engineering Hohai UniversityNanjing 210098China

A fractional plasticity model for geomaterials is proposed by using the fractional *** to the integral definition of the fractional derivative,the range of load memory for calculating the flow direction may influence the subsequent model ***,an investigation on the memory dependence of the model was *** was found that the load memory affected the stress-dilatancy behavior of the *** to the loss of memory from zero-to confiningstress states,slightly higher strain is reported,whereas an insignificant difference in the predicted deviator stress is ***,for engineering applications,starting the memory from the zero-stress state,which avoids mathematical complexity,is suggested.

关键词： Plasticity Fractional calculus Memory

A grading parameter for evaluating the grading-dependence of the shear stiffness of granular aggregates

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Particuology 2018年第1期16卷 193-198页

作者： yifei sun Yang Shen Chen Chen Key Laboratory of Ministry of Education for Ceomechanics and Embankment Engineering Jiangsu Research Center for Ceotechnical Engineering Technology Hohai University Nanjing 210098 China

To capture the grading-dependence of the shear stiffness of heterogeneous granular aggregates, a new grading parameter that considered the size distribution of the entire aggregates was developed. Both the coefficient of uniformity and median particle size decreased with increasing the grading parameter. A general increase of the shear stiffness with increasing the grading parameter was observed. Compari- son with experimental results revealed that the proposed grading parameter had a stronger correlation with the material constants of Hardin＇s stiffness formula than the coefficient of uniformity, which is a traditional grading parameter.

关键词： Shear stiffness Grading Coefficient of uniformity Particle size

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面向安全传输的低能耗无人机轨迹优化算法

计算机工程 2024年第2期50卷 59-67页

作者：吴嘉鑫孙一飞吴亚兰武继刚广东工业大学计算机学院广东广州510006

无人机凭借其灵活的机动性以及高数据传输速率,被广泛应用于大范围离散节点的数据采集工作,其机载能量的有限性也使得无人机能耗优化成为当前研究热点。然而,当环境中存在窃听节点时,如何在保障多个离散数据节点数据安全传输前提下优化... 详细信息

无人机凭借其灵活的机动性以及高数据传输速率,被广泛应用于大范围离散节点的数据采集工作,其机载能量的有限性也使得无人机能耗优化成为当前研究热点。然而,当环境中存在窃听节点时,如何在保障多个离散数据节点数据安全传输前提下优化无人机的能量消耗具有一定的挑战性。基于此,引入中继节点和安全容量,提出面向安全传输的低能耗无人机轨迹优化算法,力求从物理层面保障数据的安全传输。对无人机与地面节点的信道模型、无人机与数据节点之间的安全容量以及无人机飞行通信能耗进行建模。将问题形式化描述为以最小化无人机能耗为目标、数据节点与无人机之间的数据安全传输为主要约束的非确定性多项式难解优化问题。为解决该问题,对问题进行子问题分解,采用自组织映射方法以及定制的粒子群算法分别对无人机访问数据节点的最优次序以及在数据节点周边悬停的最佳位置进行求解,并根据现有工作提出3种基准方案进行性能对比。仿真实验结果表明,当中继节点的能量收集电路最大输出功率变化时,所提的优化算法在降低无人机总能耗方面相比BASE_D、BASE_M、BASE_R 3种基准方案分别平均提高7.25%、8.59%、11.57%。此外,在安全容量实现率方面,所提算法的性能均优于对比方案,例如,当安全容量阈值从0.001~0.500变化时,所提算法相比基准方案BASE_M平均提高23.45%。

关键词：无人机安全容量低能耗无线传能能量收集