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Observations and computations of narrow Kelvin ship wakes

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Journal of Ocean Engineering and Science 2016年第1期1卷 52-65页

作者： Francis Noblesse Chenliang Zhang Jiayi He Yi Zhu chenjun yang Wei Li State Key Laboratory of Ocean Engineering School of Naval ArchitectureOcean&Civil EngineeringShanghai Jiao Tong UniversityShanghaiChina

Computations of far-field ship waves,based on linear potential flow theory and the Hogner approximation,are reported for monohull ships and ***,far-field ship waves are computed for six monohull ships at four Froude numbers F≡V/√gL=0.58,0.68,0.86,1.58 and for six catamarans with nondimensional hull spacing s≡S/L=0.25 at two Froude numbers F s≡V/√gS=1 and ***,g is the gravitational acceleration,V and L denote the ship speed and length,and S is the separation distance between the twin hulls of a *** computations show that,although the amplitudes of the waves created by a ship are strongly influenced by the shape of the ship hull,as well known,the ray angles where the largest waves are found are only weakly influenced by the hull shape and indeed are mostly a kinematic feature of the flow around a ship *** important practical consequence of this flow feature is that the apparent wake angle of general monohull ships or catamarans(with arbitrarily-shaped hulls)can be estimated,without computations,by means of simple analytical relations;these relations,obtained elsewhere via parametric computations,are given ***,the influence of the two parameters F s and s that largely determine the ray angles of the dominant waves created by a catamaran is illustrated via computations for three catamarans with hull spacings s=0.2,0.35,0.5 at four Froude numbers F s=1,1.5,2,*** computations confirm that the largest waves created by wide and/or fast catamarans are found at ray angles that only depend on F s(*** do not depend on the hull spacing s)in agreement with an elementary analysis of lateral interference between the dominant waves created by the bows(or sterns)of the twin hulls of a *** dominant-waves ray angles predicted by the theory of wave-interference effects for monohull ships and catamarans are also compared with the observations of narrow Kelvin ship wakes reported by Rabaud and Moisy,and found to be cons

关键词： Kelvin wake Narrow ship wake Monohull ship Catamaran Wave interference Bow wave Stern wave.

DynamicMechanical and Chemorheology Analysis for the Blended Epoxy System with Polyurethane Modified Resin

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Journal of Renewable Materials 2022年第4期10卷 1081-1095页

作者： Xue Xin Yu Rong Linping Su Zhengmei Qiu chenjun yang Ming Liang Ping Ji Guoqiang Zhong Zhanyong Yao School of Qilu Transportation Shandong UniversityJinan250002China Shandong Hi-Speed Group Co. Ltd.Jinan250014China Shandong Provincial Communications Planning and Design Institute Group Co. Ltd.Jinan250031China

As the important matrix material,epoxy resin has been widely used in the composites for various *** account of the poor toughness of epoxy resin limiting their suitability for advanced applications,considerable interests have been conducted to modify the epoxy resin to meet the engineering *** this study,the bio-based polyurethane(PU)modified resin was adopted to modify the pure bisphenol-A epoxy by blending method with various *** to illuminate the curing behavior,mechanical and thermal properties,the blended epoxy systems were characterized by viscosity-time analysis,dynamic mechanical analysis(DMA)at different frequencies and temperatures,mechanical tensile test,thermogravimetric analysis(TGA)and Fourier transform infrared(FT-IR)*** results indicated that the introduction of PU modified epoxy was found to significantly inhibit the viscosity growth rates especially when the content of PU modified epoxy resin is higher than 60%.Notwithstanding the dynamic modulus and T_(g)reduced with the increment of PU modified epoxy,remarkable increment on the elongation at break was found and the flexibility was greatly promoted with the introduction of PU modified *** proportion of PU modified epoxy in the blends should be put balance considerations to obtain optimal mechanical *** results and FTIR spectrum demonstrated that the addition of PU modified epoxy did not change the thermal decomposition mechanism and chemical reaction mechanism,but the addition of PU modified epoxy inhibits the curing reaction of epoxy resin by measured and calculated the damping temperature domainT from 35.7℃ to 48.9℃.

关键词： Dynamic mechanical property chemorheology analysis blended epoxy system polyurethane modified resin

Effects of Blade Loading Distribution on the Cavitation and Excitation Forces of a Tunnel Thruster

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Journal of Shanghai Jiaotong university(Science) 2019年第2期24卷 158-167页

作者： YU Cheng DONG Xiaoqian yang chenjun LI Wei NOBLESSE Francis State Key Laboratory of Ocean Engineering Collaborative Innovation Center for Advanced Ship and Deep-Sea Exploration Shanghai Jiao Tong University

Compared with open propellers, the impeller of a tunnel thruster is more vulnerable to cavitation and structural vibration problems because the impeller is typically subject to severe non-uniformity of inflow produced by the blunt gearbox. Model tests and numerical simulations are carried out in the cavitation tunnel of Shanghai Jiao Tong University for a tunnel thruster using a "flat plate" impeller and a tip-unloaded one. The characteristics of fluctuating pressures on the tunnel wall and the resultant excitation forces are investigated. It is found that although unloading the blade tips of an impeller is effective in reducing the fluctuating pressures in a local tunnel wall area near the tips, the same trend does not apply to the case of the excitation forces. The results show that care should be taken when the experimentally measured fluctuating pressures are utilized as the input to the analysis of structural vibrations.

关键词： tunnel thruster cavitation fluctuating pressures computational fluid dynamics(CFD)

Decoding the Cellular Trafficking of Prion-like Proteins in Neurodegenerative Diseases

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Neuroscience Bulletin 2024年第2期40卷 241-254页

作者： chenjun Hu Yiqun Yan Yanhong Jin Jun yang Yongmei Xi Zhen Zhong Department of Neurology of the Second Afliated Hospital and Department of Human Anatomy Histology and EmbryologyZhejiang University School of MedicineHangzhou 310058China Department of Physiology and Department of Cardiology of the Second Afliated Hospital Zhejiang University School of MedicineHangzhou 310058China Division of Human Reproduction and Developmental Genetics Women’s Hospital and Institute of GeneticsZhejiang University School of MedicineHangzhou 310006China

The accumulation and spread of prion-like proteins is a key feature of neurodegenerative diseases(NDs)such as Alzheimer’s disease,Parkinson's disease,or Amyotrophic Lateral *** a process known as‘seeding’,prion-like proteins such as amyloid beta,microtubule-associated protein tau,α-synuclein,silence superoxide dismutase 1,or transactive response DNA-binding protein 43 kDa,propagate their misfolded conformations by transforming their respective soluble monomers into *** and molecular evidence of prion-like propagation in NDs,the clinical relevance of their‘seeding’capacities,and their levels of contribution towards disease progression have been intensively studied over recent *** review unpacks the cyclic prion-like propagation in cells including factors of aggregate internalization,endo-lysosomal leaking,aggregate degradation,and *** on the importance of the role of prion-like protein aggregates in NDs,whether causal or consequent,are also *** lead to a greater understanding of ND pathogenesis and increased potential for therapeutic strategies.

关键词： Neurodegenerative diseases Prion-like propagation Seeding Endocytosis Endolyosomal leaking Degradation

Research about building facility management system based on BIM 3rd

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Research about building facility management system based on ...

Finite-time bearing-only formation of first-order multi-agent systems under pinning control

2011 International Conference on Information Management and Engineering(ICIME 2011)

作者： chenjun yang Gang Wei Engineering Research Center for Enterprise Digital Technology Ministry of EducationTongji University

ISBN: (纸本)9781612842387

This paper discusses about how to utilize current technologies to design and implement a building facility management (BFM) system based on 3D BIM model, satisfying modern intelligent building’s demand for facility management (FM). Implementation methods of the system include: using Navisworks customized development technology to combine BIM technology with relational database so as to manage information of management objects and maintain tree-structure relation between them. We use C/S architecture to allocate tasks appropriately, use LOD (Levels of Detail) technology as a source of reference to accelerate model construction speed and utilize Navisworks .NET AIP to implement data visualization. The system provides an integrated management environment with abundant functionalities, excellent interaction and visualization capabilities. But there are still some disadvantages in system deployment and launch aspects.

关键词： facility management BIM C/S architecture Navisworks customized development

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Science China(Information Sciences) 2024年第5期67卷 331-332页

作者： chenjun LIU Wei ZHU Fenglan SUN Key Laboratory of Intelligent Analysis and Decision on Complex Systems Chongqing University of Posts and Telecommunications

Formation control of multi-agent systems(MASs) has been applied in various fields, such as autonomous navigation and target encirclement, due to its ability to facilitate coordination and achieve the desired formation or space configuration. Bearing-based formation control offers greater practicality than position-based or distance-based approaches since bearing information is inexpensive and simple to acquire, such as utilizing optical cameras.

关键词： Multi agent systems

基于涡格法的任意环量分布螺旋桨数值设计方法

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中国造船 2018年第2期59卷 90-102页

作者：王琪杨晨俊上海交通大学海洋工程国家重点实验室高新船舶与深海开发装备协同创新中心上海200240

基于升力面理论涡格法提出了一种任意环量分布螺旋桨的数值设计方法,该方法对假定的桨叶拱弧面几何和螺距分布,利用涡格法求解其环量面分布,并根据该分布与给定分布的差,通过Newton-Raphson迭代获得拱度和螺距的修正量,从而逐步逼近具... 详细信息

基于升力面理论涡格法提出了一种任意环量分布螺旋桨的数值设计方法,该方法对假定的桨叶拱弧面几何和螺距分布,利用涡格法求解其环量面分布,并根据该分布与给定分布的差,通过Newton-Raphson迭代获得拱度和螺距的修正量,从而逐步逼近具有给定环量分布的桨叶几何。以DTNSRDC-4382大侧斜桨为对象进行了数值考察,结果表明:设计方法具有良好的网格收敛性;拱弧面几何及螺距分布的初值在合理范围内变化时,设计结果无初值依赖性;与RANS计算相结合,本文方法可达到较高的水动力设计精度。

关键词：螺旋桨涡格法任意环量分布 Newton-Raphson method

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七叶侧斜螺旋桨水动力性能优化

中国造船 2016年第4期57卷 1-13页

作者：饶志强杨晨俊上海交通大学海洋工程国家重点实验室高新船舶与深海开发装备协同创新中心上海200240

论文对某七叶侧斜螺旋桨进行了多目标数值优化。螺旋桨的弦长分布由多项式来表达,螺距、拱度和侧斜分布由B样条曲线控制。剖面厚度分布由PARSEC表达式修改,并采用SJ系列拱线代替了原始拱线。螺旋桨的性能预报采用面元法,优化算法采用非... 详细信息

论文对某七叶侧斜螺旋桨进行了多目标数值优化。螺旋桨的弦长分布由多项式来表达,螺距、拱度和侧斜分布由B样条曲线控制。剖面厚度分布由PARSEC表达式修改,并采用SJ系列拱线代替了原始拱线。螺旋桨的性能预报采用面元法,优化算法采用非排序微分进化算法。首先由相关度分析减少设计变量并确定其取值范围,然后以效率和叶梢最小压力为目标进行优化,并采用开源程序Open Foam对优化结果进行了RANS计算和分析。计算结果表明:优化桨的盘面比更小但叶梢侧斜略大,折中优化桨效率比原桨提高约2%,且叶梢压力分布有所改善。

关键词：七叶螺旋桨多目标优化 B样条面元法 OpenFoam

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伴流分布对螺旋桨毂帽鳍节能效果的影响

中国造船 2021年第1期62卷 1-10页

作者：张恒李巍杨晨俊中国船舶及海洋工程设计研究院上海200011 上海交通大学海洋工程国家重点实验室上海200240

基于CFD模拟与分析,考察船尾伴流分布对螺旋桨毂帽鳍节能效果的影响,并对敞水条件下设计的毂帽鳍进行适伴流优化。采用StarCCM+软件,分别在均匀来流以及KCS船尾伴流中进行螺旋桨毂帽鳍水动力性能的RANS模拟,比较毂帽鳍在不同来流场中的... 详细信息

基于CFD模拟与分析,考察船尾伴流分布对螺旋桨毂帽鳍节能效果的影响,并对敞水条件下设计的毂帽鳍进行适伴流优化。采用StarCCM+软件,分别在均匀来流以及KCS船尾伴流中进行螺旋桨毂帽鳍水动力性能的RANS模拟,比较毂帽鳍在不同来流场中的节能效果,并对节能机理进行了分析。针对KCS船实尺度伴流场,通过鳍片螺距角的改变,优化节能效果。计算结果表明:毂帽鳍在非均匀伴流中的节能效果显著高于在敞水中,敞水中的毂帽鳍的最优设计方案不一定适用于非均匀伴流,适当改变毂帽鳍的几何参数可进一步提高其在船尾伴流中的节能效果。

关键词：毂帽鳍节能伴流场 CFD