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Optimal design of Stewart platforms based on expanding the control bandwidth while considering the hydraulic system design

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2009年第1期10卷 22-30页

作者： Wei WANG Hua-yong YANG Jun ZOU xiao-dong ruan Xin FU State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

We proposed an optimal design method to expand the bandwidth for the control of large hydraulic Stewart *** method is based on generalized natural frequency and takes hydraulic oil into consideration.A Lagrangian formulation which considers the whole leg inertia is presented to obtain the accurate equivalent mass *** the model,the effect of leg inertia and the influence of design parameters on the generalized natural frequency are ***,numerical examples are presented to validate and confirm the efficiency of the mathematical *** results show that the leg inertia,especially the piston part plays an important role in the *** optimum diameter ratio of the base to the moving platform is between 2 and 3,and the optimum joint angle ratio of the base to the moving platform is about *** smaller joint angles and a longer leg stroke are favorable for raising system *** system oil should be preprocessed for large platforms with a requirement for good dynamic performance.

关键词： Large Gough-Stewart platform Optimal design Control bandwidth Leg inertia Generalized natural frequency

Evaluation of the hemolysis and fluid dynamics of a ventricular assist device under the pulsatile flow condition

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Journal of Hydrodynamics 2019年第5期31卷 965-975页

作者： Huan Li Zhe Gou Feng Huang xiao-dong ruan Wen-wei Qian Xin Fu State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang UniversityHangzhou 310027China College of Metrology and Measurement Engineering China Jiliang UniversityHangzhou 310018China Department of Cardio-chest Surgery Zhejiang Provincial Peopled HospitalHangzhou 310014China

When the rotary blood pumps are used as ventricular assist devices,the pump flow rate will have a pulsatile component even at a constant impeller rotational speed due to the remaining beating of the natural ***,previous studies on the in vitro hemolysis evaluation of a rotary blood pump have always been conducted under steady states and this pulsation was not taken into *** this study,the hemolysis in a centrifugal blood pump is evaluated under the pulsatile flow condition in *** required time-varying flow rate is obtained by conducting a system simulation of the pump-assisted cardiovascular system,and realized by controlling a pulsation unit in the *** results of our tests indicate a significant increase in hemolysis under the pulsatile flow condition compared with the non-pulsatile *** reveal the flow characteristics responsible for the higher hemolysis,transient computational fluid dynamic simulations are then *** study suggests that traditional hemolysis evaluation under the steady states may not fully represent the hemolytic performance in the clinical *** the ventricular assist pumps at the design stage,eliminating the concern about the extra hemolysis under the pulsatile condition will be helpful for the subsequent in vivo experiments.

关键词： Ventricular assist devices hemolysis pulsatile flow cardiovascular system numerical simulation

纤维增强复合材料固化变形的研究与控制综述（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2019年第5期20卷 311-333页

作者： Jiao-yuan LIAN Zhong-bin XU xiao-dong ruan Institute of Process Equipment College of Energy EngineeringZhejiang University State Key Laboratory of Fluid Power and Mechatronic Systems Zhejiang University

目的:固化变形问题是纤维增强复合材料结构件固化成形及应用过程中的一大阻碍。本文旨在综述引起固化变形的原因和机理,归纳和评价固化变形的控制方法,以及指出目前存在的问题与不足。方法:1.通过对国内外文献的大量阅读与分析,得到固... 详细信息

目的:固化变形问题是纤维增强复合材料结构件固化成形及应用过程中的一大阻碍。本文旨在综述引起固化变形的原因和机理,归纳和评价固化变形的控制方法,以及指出目前存在的问题与不足。方法:1.通过对国内外文献的大量阅读与分析,得到固化变形问题的产生机理及近年来的研究进展;2.通过对该领域论文的分类和归纳,总结出固化变形的主要控制策略,并分类讨论每项策略的控制措施。结论:1.固化变形的产生机理主要有热变形、化学收缩变形和模具作用3种。2.本文归纳了固化变形的五类控制方法:模具补偿、固化工艺优化、结构件优化设计、模具接触面优化以及开发新方法。3.针对各控制策略的优点,本文分析和总结了它们的适用场合以及控制效果。4.在固化变形的研究方面,目前仍然存在许多问题与不足。

关键词：纤维增强复合材料固化变形有限元分析过程模拟控制策略

基于伴随求解的核主泵轴向力优化方法（英文）

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2019年第11期20卷 852-863页

作者： Jia-ming WANG Peng-fei WANG Xu ZHANG xiao-dong ruan Xin FU State Key Laboratory of Fluid Power&Mechatronic Systems Zhejiang UniversityHangzhou 310027China School of Engineering Zhejiang University City CollegeHangzhou 310015China

目的:核主泵轴向力过大容易造成水润滑轴承磨损,因此在保证扬程和效率性能的同时需要降低核主泵轴向力。本文旨在建立目标性能与叶轮几何形状的函数关系,探究基于伴随求解的扭曲叶轮的变形方案,在保证扬程不变的条件下同步优化叶轮的轴... 详细信息

目的:核主泵轴向力过大容易造成水润滑轴承磨损,因此在保证扬程和效率性能的同时需要降低核主泵轴向力。本文旨在建立目标性能与叶轮几何形状的函数关系,探究基于伴随求解的扭曲叶轮的变形方案,在保证扬程不变的条件下同步优化叶轮的轴向力和效率,并找到影响该综合性能的叶轮关键区域。创新点:1.提出一种同步改进多个目标性能的叶轮形状优化方法;2.将伴随求解和径向基函数网格变形相结合以实现核主泵叶轮三维曲面优化。方法:1.通过理论分析,建立基于径向基函数网格变形的伴随优化方法,并在开源平台编写迭代程序;2.通过公式推导,构建扬程、效率和轴向力对应的目标函数(公式(19)^(21)),并运用正交实验确定各个目标函数的参数因子;3.通过迭代计算,在保证扬程不变的条件下实现轴向力和效率的同步优化,确定影响该综合性能的关键区域(图8),并获得叶轮的改进设计方案;4.通过流场分析,对比改进前后流场内部的压力和流速分布情况(图9和10),并验证改进方案的可行性和有效性。结论:1.与传统的随机算法相比,该优化方法直接沿梯度方向进行迭代优化,可以避免使用大量样本数据来寻找优化路径;2.该优化方法将伴随求解和径向基函数网格变形相结合,实现了流场计算和结构变形的自动化,可以保证流场网格光滑高效地更迭;3.叶轮靠近出口边的下半部分是同步优化核主泵轴向力和效率的关键区域。

关键词：核主泵伴随方法径向基函数轴向力形状优化

Preparation of MXene-based hybrids and their application in neuromorphic devices

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International Journal of Extreme Manufacturing 2024年第2期6卷 164-188页

作者： Zhuohao xiao xiaodong xiao Ling Bing Kong Hongbo dong Xiuying Li Bin He Shuangchen ruan Jianpang Zhai Kun Zhou Qin Huang Liang Chu School of Materials Science and Engineering Jingdezhen Ceramic UniversityJingdezhen 333403JiangxiPeople’s Republic of China School of Mechanical and Vehicle Engineering Linyi UniversityLinyi 276000ShandongPeople’s Republic of China College of New Materials and New Energies Shenzhen Technology UniversityShenzhen 518118GuangdongPeople’s Republic of China School of Mechanical&Aerospace Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore Ningbo Institute of Materials Engineering and Technology Chinese Academy of ScienceNingbo 315201ZhejiangPeople’s Republic of China Institute of Carbon Neutrality and New Energy&School of Electronics and Information Hangzhou Dianzi UniversityHangzhou 310018ZhejiangPeople’s Republic of China

The traditional von Neumann computing architecture has relatively-low information processing speed and high power consumption,making it difficult to meet the computing needs of artificial intelligence(AI).Neuromorphic computing systems,with massively parallel computing capability and low power consumption,have been considered as an ideal option for data storage and AI computing in the ***,as the fourth basic electronic component besides resistance,capacitance and inductance,is one of the most competitive candidates for neuromorphic computing systems benefiting from the simple structure,continuously adjustable conductivity state,ultra-low power consumption,high switching speed and compatibility with existing CMOS *** memristors with applying MXene-based hybrids have attracted significant attention in recent ***,we introduce the latest progress in the synthesis of MXene-based hybrids and summarize their potential applications in memristor devices and neuromorphological *** explore the development trend of memristors constructed by combining MXenes with other functional materials and emphatically discuss the potential mechanism of MXenes-based memristor ***,the future prospects and directions of MXene-based memristors are briefly described.

关键词： MXene etching fabrication memristor neuromorphic

Dynamic thermal rating assessment of oil-immersed power transformers for multiple operating conditions

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High Voltage 2024年第1期9卷 195-205页

作者： Chen Zhang Xuzhu dong Jiangjun ruan Yongqing Deng School of Electrical Engineering and Automation Wuhan UniversityWuhanHubeiChina

In this article,the dynamic thermal rating assessment method of oil-immersed power transformer with multiple operating conditions is proposed,considering the constraints of hot spot temperature(HST),top oil temperature,losses of life and the maximum allowable current of on-load tap changer(OLTC)or bushing,which can determine the dynamic load curves under different operating conditions and give the most sensitive constraints to limit the dynamic load *** improve the accuracy of HST estimation,the temperature estimation model is also improved and the thermal parameters are optimised using the HST measured by optical ***,several application examples are studied for transformers in different *** results show that the normal cyclic dynamic transformer rating(DTR)is mainly limited by the losses of life when the ambient temperature is high,and the average load factor can be increased to 0.82 with a maximum load capacity of *** main limiting factor of short-term DTR is the OLTC or bushing current constraint,and the average load factor can be increased to *** maximum load capacity of the transformer under both operating conditions is 23%and 50%higher than its rated load capacity,indicating that the transformer still has a large load potential available.

关键词： load thermal power

Finite Difference-Peridynamic Differential Operator for Solving Transient Heat Conduction Problems

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Computer Modeling in Engineering & Sciences 2024年第9期140卷 2707-2728页

作者： Chunlei ruan Cengceng dong Zeyue Zhang Boyu Chen Zhijun Liu School of Mathematics&Statistics Henan University of Science&TechnologyLuoyang471023China Longmen Laboratory Luoyang471023China

Transient heat conduction problems widely exist in *** previous work on the peridynamic differential operator(PDDO)method for solving such problems,both time and spatial derivatives were discretized using the PDDO method,resulting in increased complexity and programming *** this work,the forward difference formula,the backward difference formula,and the centered difference formula are used to discretize the time derivative,while the PDDO method is used to discretize the spatial *** new schemes for solving transient heat conduction equations have been developed,namely,the forward-in-time and PDDO in space(FT-PDDO)scheme,the backward-in-time and PDDO in space(BT-PDDO)scheme,and the central-in-time and PDDO in space(CT-PDDO)*** stability and convergence of these schemes are analyzed using the Fourier method and Taylor’s *** show that the FT-PDDO scheme is conditionally stable,whereas the BT-PDDO and CT-PDDO schemes are unconditionally *** stability conditions for the FT-PDDO scheme are less stringent than those of the explicit finite element method and explicit finite difference *** convergence rate in space for these three methods is *** constructed schemes are applied to solve one-dimensional and two-dimensional transient heat conduction *** accuracy and validity of the schemes are verified by comparison with analytical solutions.

关键词： Peridynamic differential operator finite difference method stability transient heat conduction problem

A 10-yr Rainfall and Cloud-to-Ground Lightning Climatology over Coastal and Inland Regions of Guangdong,China during the Pre-Summer Rainy Season

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Journal of Meteorological Research 2024年第3期38卷 469-488页

作者： Yuqing ruan Rudi XIA Xinghua BAO dong ZHENG Yan SHEN Jinfang YIN State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesChina Meteorological AdministrationBeijing100081China Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters Nanjing University of Information Science&TechnologyNanjing210044China National Meteorological Information Centre China Meteorological AdministrationBeijing100081China

A comparative analysis of the spatiotemporal distribution characteristics of rainfall and lightning in coastal and inland areas of Guangdong Province of China during the pre-summer rainy season(PSRS)from 2008 to 2017 reveals distinct *** the inland target region(ITR),rainfall is concentrated in the central and eastern mountainous *** exhibits a bimodal diurnal variation,with peaks in the afternoon and *** afternoon peak becomes more pronounced during the post-monsoon-onset period because of the increased rainfall ***,in the coastal target region(CTR),rainfall concentrates around mountainous ***,CTR’s rainfall is weaker than ITR’s during the pre-monsoon-onset period,primarily associated with the lower-level moisture outflow in CTR,but it strengthens significantly during the post-monsoon-onset period owing to enhanced moisture ***’s diurnal rainfall variation transitions from bimodal to a single broad peak during the post-monsoon-onset period,influenced by changes in both rainfall frequency and *** contrast to rainfall,the spatiotemporal distribution of lightning centers remains relatively stable during the *** strongest center is located over ITR’s plains west of the rainfall center,with a secondary center in the western plains of *** activity significantly increases during the post-monsoon-onset period,particularly in ITR,primarily because of the increased lightning *** diurnal lightning flash density and lightning hours show a single afternoon peak in the two target regions,and the timing of the peak in ITR is approximately two hours later than in *** circulation analysis indicates that during early morning,the lower atmosphere is nearly neutral in *** advected warm,moist,unstable airflow,combined with topography,favors convection *** the afternoon,solar radiation increases thermal instability,further enhancing the convection frequency and in

关键词： rainfall lightning spatiotemporal distribution diurnal variation pre-summer rainy season

Burst-mode pulse generation in passively mode-locked all-fiber green/orange lasers at 543 nm and 602 nm

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Photonics Research 2024年第6期12卷 1231-1238页

作者： QIUJUN ruan JINHAI ZOU CHUNNA FENG TINGTING CHEN HANG WANG ZHIPENG dong ZHENGQIAN LUO Fujian Key Laboratory of Ultrafast Laser Technology and Applications School of Electronic Science and EngineeringXiamen UniversityXiamen 361005China Shenzhen Research Institution of Xiamen University Shenzhen 518000China

We report on the experimental realization of,to the best of our knowledge,the first green and orange passively mode-locked all-fiber *** mode-locking in the burst-pulse status is achieved at the wavelengths of 543.3 nm and 602.5 *** figure-9 cavity comprises the fiber end-facet mirror,gain fiber(Ho^(3+):ZBLAN fiber or Pr^(3+)/Yb^(3+):ZBLAN fiber),and fiber loop mirror(FLM).The FLM with long 460 HP fiber is not only used as an output mirror,but also acts as a nonlinear optical loop mirror for initiating visible-wavelength *** green/orange mode-locked fiber lasers with the fundamental repetition rates of 3.779/5.662 MHz produce long bursts containing ultrashort pulses with the 0.85/0.76 GHz intra-burst repetition rates,*** ultrashort intra-burst pulses stem from the dissipative four-wave-mixing effect in the highly nonlinear FLM as well as the intracavity Fabry–Perot *** bursts of 22.2/11.6 ns with ultrashort pulses of 87/62 ps are obtained in our *** visible-wavelength passively mode-locked lasers in an all-fiber configuration and burst-mode would represent an important step towards miniaturized ultrafast fiber lasers and may contribute to the applications in ablation-cooling micromachining,biomedicine imaging,and scientific research.

关键词： fiber passive pulse