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Flexural wave bandgap properties of phononic crystal beams with interval parameters

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Applied Mathematics and Mechanics(English Edition) 2023年第2期44卷 173-188页

作者： Feiyang HE Zhiyu SHI Denghui QIAN Y.K.LU yujia xiang Xuelei FENG State Key Laboratory of Mechanics and Control of Mechanical Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China School of Naval Architecture&Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100Jiangsu ProvinceChina Department of Ophthalmology University of PittsburghPittsburgh 15213PAU.S.A.

Uncertainties are unavoidable in practical engineering,and phononic crystals are no *** this paper,the uncertainties are treated as the interval parameters,and an interval phononic crystal beam model is established.A perturbation-based interval finite element method(P-IFEM)and an affine-based interval finite element method(A-IFEM)are proposed to study the dynamic response of this interval phononic crystal beam,based on which an interval vibration transmission analysis can be easily implemented and the safe bandgap can be ***,two numerical examples are investigated to demonstrate the effectiveness and accuracy of the P-IFEM and *** show that the safe bandgap range may even decrease by 10%compared with the deterministic bandgap without considering the uncertainties.

关键词： phononic crystal beam interval parameter safe bandgap perturbation-based interval finite element method(P-IFEM) affine-based interval finite element method(A-IFEM) interval vibration transmission analysis

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大学教师在线教学实践及认知评价分析

上海第二工业大学学报 2024年第1期41卷 101-108页

作者：马克星相雨佳贺书锋上海第二工业大学经济与管理学院上海201209

教育者是推动在线教学发展的关键,对大学教师进行问卷调查,选择有在线教学经历的大学教师数据展开分析。结果显示:①在线教学实践方面,大部分大学教师能够快速适应在线教学,并选择教师参与度高的在线教学方式,经过教学实践,大学教师在... 详细信息

教育者是推动在线教学发展的关键,对大学教师进行问卷调查,选择有在线教学经历的大学教师数据展开分析。结果显示:①在线教学实践方面,大部分大学教师能够快速适应在线教学,并选择教师参与度高的在线教学方式,经过教学实践,大学教师在线教学能力明显提升;②在线教学认知方面,大学教师对在线教学优势和不足的认知较为一致,在线教学将成为常态化教学活动的重要模式,其发展需要教师、学生和学校的共同努力;③在线教学常态化是重要趋势,未来需积极探索在线教学的课程思政建设,多主体共同促进教学质量的提升,推进教育数字化发展。

关键词：在线教学大学教师教学实践认知评价教育数字化

基于Warshall-Floyd算法的船舶结构噪声传递路径研究

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振动与冲击 2019年第2期38卷 82-89,97页

作者：向育佳季振林赵欣棠哈尔滨工程大学动力与能源工程学院哈尔滨150001

结构振动是船舶主要的噪声源,传统测试方法难以有效分析结构噪声的传递路径。根据统计能量分析(SEA)理论中的振动子系统概念,利用赋权图方法分析结构噪声的传递规律。将相似模态群抽象成赋权图的顶点,结合能量平衡方程中SEA矩阵建立顶... 详细信息

结构振动是船舶主要的噪声源,传统测试方法难以有效分析结构噪声的传递路径。根据统计能量分析(SEA)理论中的振动子系统概念,利用赋权图方法分析结构噪声的传递规律。将相似模态群抽象成赋权图的顶点,结合能量平衡方程中SEA矩阵建立顶点之间的邻接关系,采用路径效率方法和统计熵方法两种分析方法,将物理模型转化为最短路径问题的权值矩阵。通过Warshall-Floyd最短路径算法找出权值矩阵中任意两个顶点之间的前N条最短路径,得出任意空间位置的结构噪声源到目标舱室的前N条主要传递路径,对比能量传递路径在不同频带和不同振动模态群的差异,并分析各主要路径在能量传递过程中的权重,揭示船舶结构噪声源传递的一般规律,为降低船舶结构噪声提供指导。

关键词：结构噪声传递路径分析路径效率方法(PEM) 统计熵方法(SEM) Warshall-Floyd算法最短路径

参数不确定性内声场分析的封闭区间有限元方法

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振动与冲击 2022年第18期41卷 25-32页

作者：向育佳史治宇冯雪磊南京航空航天大学航空学院机械结构力学及控制国家重点实验室南京210016

针对含有不确定但有界参数的内声场预测问题,主要的区间建模方法为逐单元的区间有限元法(EBE-IFEM)和区间摄动有限元法(IPFEM)。但由于IPFEM在级数展开时存在非保守近似的缺陷,EBE-IFEM在利用拉格朗日乘子法来约束扩增的节点自由度时增... 详细信息

针对含有不确定但有界参数的内声场预测问题,主要的区间建模方法为逐单元的区间有限元法(EBE-IFEM)和区间摄动有限元法(IPFEM)。但由于IPFEM在级数展开时存在非保守近似的缺陷,EBE-IFEM在利用拉格朗日乘子法来约束扩增的节点自由度时增加了内存消耗并降低了迭代计算效率,现有方法很难兼备保守的结果和高的计算效率。为此,提出了一种新的封闭区间有限元方法(Enclosing-IFEM),结合“混合节点-单元”(MNE)的组装策略来缩减自由度,该方法能够在满足结果保守性的前提下,提高求解效率。而且,Enclosing-IFEM的区间动力学方程可以直接转化为“并矢积”形式,解决了基于Sherrman-Morrison-Woodbury(S-M-W)级数的区间摄动有限元法(SMW-IPFEM)的动力学拓展问题。最后,将蒙特卡罗方法以及它的区间有限元方法作为参考解,通过两个数值算例验证了Enclosing-IFEM的计算精度和效率。

关键词：封闭区间有限元方法(Enclosing-IFEM) S-M-W级数不确定性声场分析不确定但有界参数

Controllability Gramian-based measures of graph product networks

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Science China(Information Sciences) 2024年第10期67卷 315-331页

作者： Yuequan xiang Linying xiang School of Information Science and Engineering Northeastern University School of Artificial Intelligence Tiangong University

This paper addresses the controllability measures of composite networks based on graph products, in which the graph product networks are either Kronecker product networks or Kronecker sum *** primary objective pursued here is to reveal the controllability Gramian-based measure links between the graph product composite network and its subnetworks. First, the analytical expression of the average controllability for the Kronecker product network is derived by using the corresponding controllability measures of its subnetworks. An upper bound of volumetric control energy is further obtained for the Kronecker product network. Then, the upper bounds are derived for the controllability measures of the Kronecker sum network,which provide a valuable reference for designing controllable networks in practical applications. Finally, the controllability of the Kronecker product network is compared with that of the Kronecker sum network, and it is found that when the subnetworks satisfy certain conditions, the Kronecker product network has better average controllability than the Kronecker sum network.

关键词： composite network graph product controllability Gramian-based measure average controllability control energy

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血管介入微创手术机器人系统控制研究

江西师范大学学报（自然科学版） 2020年第3期44卷 231-234页

作者：项毓嘉谢叻上海交通大学医疗机器人研究院上海200240 泉州师范学院福建泉州362000

医生在进行血管介入手术过程中需要实时的X射线图像引导,而长时间的射线辐射会严重危害医生的健康.为了减小介入医生在手术过程中受到的辐射伤害,该文研究了一款基于双主手控制的血管介入微创手术机器人系统,并对其整体框架和控制方法... 详细信息

医生在进行血管介入手术过程中需要实时的X射线图像引导,而长时间的射线辐射会严重危害医生的健康.为了减小介入医生在手术过程中受到的辐射伤害,该文研究了一款基于双主手控制的血管介入微创手术机器人系统,并对其整体框架和控制方法进行研究.医生可通过上位机界面交互,进行主从遥操作,驱动从端机构完成介入手术操作.最后进行了血管模型试验,验证了该文的介入手术机器人具备多器械协同递送的功能.

关键词：血管介入主从控制遥操作多器械协同

Dual-ion carrier storage through Mg^(2+) addition for high-energy and long-life zinc-ion hybrid capacitor

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 179-185页

作者： Junjie Zhang xiang Wu School of Materials Science and Engineering Shenyang University of TechnologyShenyang 110870China

Cation additives can efficiently enhance the total electrochemical capabilities of zinc-ion hybrid capacitors (ZHCs).However their energy storage mechanisms in zinc-based systems are still under ***,we modulate the electrolyte and achieve dual-ion storage by adding magnesium *** we assemble several Zn//activated carbon devices with different electrolyte concentrations and investigate their electrochemical reaction dynamic *** zinc-ion capacitor with Mg^(2+)mixed solution delivers 82 mAh·g^(-1)capacity at 1 A·g^(-1) and maintains 91%of the original capacitance after 10000 *** is superior to the other assembled zinc-ion devices in single-component *** finding demonstrates that the double-ion storage mechanism enables the superior rate performance and long cycle lifetime of ZHCs.

关键词： zinc-ion hybrid capacitor MgSO_(4) electrolyte rate performance storage mechanism

Microstructure and mechanical properties of a cast TRIP-assisted multiphase stainless steel

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China Foundry 2024年第3期21卷 221-228页

作者： Meng-xin Wang Zi-xiang Wu Jing-yu He xiang Chen School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Ministry of EducationBeijing 100084China

Stainless steels are used in a wide range of complex environments due to their excellent corrosion *** stainless steels can offer an excellent combination of strength,toughness and corrosion resistance due to the coexistence of different *** microstructure and mechanical properties of a novel cast multiphase stainless steel,composed of martensite,ferrite,and austenite,were investigated following appropriate heat treatment processes:solution treatment at 1,050℃ for 0.5 h followed by water quenching to room temperature,and aging treatment at 500℃ for 4 h followed by water quenching to room *** show reversed austenite is formed by diffusion of Ni element during aging process,and the enrichment of Ni atoms directly determines the mechanical stability of *** austenite with a lower Ni content undergoes a martensitic transformation during plastic *** tensile strength of the specimen exceeds 1,100 MPa and the elongation exceeds 24%after solid solution,and further increases to 1,247 MPa and 25%after aging *** enhancement is due to the TRIP effect of austenite and the precipitation of the nanoscale G-phase pinning dislocations in ferrite and martensite.

关键词： multiphase stainless steel mechanical properties TRIP effect reversed austenite G-phase

Highly homogeneous zero-index metamaterials make devices more compact and perform better

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Light(Science & Applications) 2024年第5期13卷 806-807页

作者： Wei-xiang Jiang State Key Laboratory of Millimeter Waves School of Information Science and EngineeringSoutheast University210096 NanjingChina

A highly homogeneous microwave zero-index metamaterial based on high-permittivity SrTiO3 ceramics is demonstrated to realize the small-aperture high-directivity *** a novel technique is a remarkable step forward to de... 详细信息

关键词： ceramics SrTiO3 Highly