检索结果-南通市图书馆

An efficient and modular modeling for launch dynamics of tubed rockets on a moving launcher

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第6期17卷 2011-2026页

作者： Qin-bo Zhou xiao-ting rui Guo-ping Wang Jian-shu Zhang Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjingJiangsu Province210094PR China

This paper develops a modular modeling and efficient formulation of launch dynamics with marching fire(LDMF)using a mixed formulation of the transfer matrix method for multibody systems(MSTMM)and Newton-Euler *** a ground-borne multiple launch rocket systems(MLRS),the focus is on the launching subsystem comprising the rocket,flexible tube,and tube *** launching subsystem is treated as a coupled rigid-flexible multibody system,where the rocket and tube tail are treated as rigid bodies while the flexible tube as a beam with large ***,the tube and tube tail can be elegantly handled by the MSTMM,a computationally efficient order-N ***,the equation of motion of the in-bore rocket with relative kinematics *** tube using the Newton-Euler method is ***,the rocket,tube,and tube tail dynamics are coupled,yielding the equation of motion of the launching subsystem that can be regarded as a building block and further integrated with other *** deduced dynamics equation of the launching subsystem is not limited to ground-borne MLRS but also fits for tanks,self-propelled artilleries,and other air-borne and naval-borne weapons undergoing large *** simulation results of LDMF are given and partially verified by the experiment.

关键词： Launch dynamics Marching fire Transfer matrix method for multibody systems Multiple launch rocket system

A novel launch dynamics measurement system for multiple launch rocket system and comparative analysis with numerical simulations

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第2期17卷 671-681页

作者： Li-lin Gu xiao-ting rui Guo-ping Wang Yi An Fu-feng Yang Min Wei Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjing 210094PR China School of Physical and Mathematical Science Nanjing Tech UniversityNanjing 211816PR China

In this paper,a novel launch dynamics measurement system based on the photoelectric sensor pair is *** actual muzzle time(i.e.a time duration that originates from the initial movement to the rocket’s departure from the muzzle)and the muzzle velocity are *** with the classical methods,the actual muzzle time is obtained by eliminating the ignition *** comparative analysis method is proposed with numerical simulations established by the transfer matrix method for multibody *** experiment results indicate that the proposed measurement system can effectively measure the actual muzzle time and reduce the error of classical methods,which match well with the simulation results showing the launch dynamics model is reliable and helpful for further analysis and design of the MLRS.

关键词： Multiple launch rocket system Photoelectric sensor Launch dynamics measurement system Model verification Transfer matrix method for multibody systems

Adaptive control of track tension estimation using radial basis function neural network

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2021年第4期17卷 1423-1433页

作者： Ping-xin Wang xiao-ting rui Hai-long Yu Guo-ping Wang Dong-yang Chen Institute of Launch Dynamics Nanjing University of Science and TechnologyNanjing210094China College of Electrical Energy and Power EngineeringYangzhou UniversityYangzhou225000China

Track tension is a major factor influencing the reliability of a *** order to reduce the risk of track peel-off,it is necessary to keep track tension ***,it is difficult to measure the dynamic tension during off-road *** on the analysis of the relation and external forces depending on free body diagrams of the idler,idler arm,road wheel and road arm,a theoretical estimation model of track tension is *** estimation results with multibody dynamics simulation results,the rationality of track tension monitor is *** the aid of this monitor,a track tension control system is designed,which includes a self-tuning proportional-integral-derivative(PID)controller based on radial basis function neural network,an electro-hydraulic servo system and an idler *** tightness of track can be adjusted by turning the idler *** results of the vehicle starting process indicate that the controller can reach different expected tensions quickly and *** with a traditional PID controller,the proposed controller has a stronger anti-disturbance ability by amending control parameters online.

关键词： Track tension Monitor Multibody dynamics Neural network Anti-disturbance ability

Suppression of vortex-induced vibrations of a flexible riser by adding helical strakes

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2019年第3期31卷 622-631页

作者： Dong-yang Chen Laith K. Abbas Guo-ping Wang xiao-ting rui Wei-jie Lu School of Hydraulic Energy and Power Engineering Yangzhou University Yangzhou 225127 China Institute of La unch Dynamics Nanjing University of Science and Technology Nanjing 210094 China Nanjing Aerosun Corporation Nanjing 210000 China

3-D computational fluid dynamics/ computational structure dynamics (CFD/CSD) numerical two-way coupling simulations are conducted for a flexible rise in order to study the dynamic response performance of the riser with and without helical strakes exposed to the vortex-induced vibration (VIV). The VIV responses of a PVC riser without helical strakes are computed and compared with experimental data, to verify the accuracy of the present two-way coupling method. Subsequently, the dynamic behaviors of a short PVC riser with different kinds of helical strakes are studied. The vibration amplitudes along the riser, the trajectories of the riser's monitor point and the vortex shedding contours are obtained in a series of simulations. The helical strakes5 VIV suppression mechanisms are found involving the breaking of the vortex structures and the reduction of the vortex shedding frequency of the bare riser. Moreover, a good suppression effect can be achieved by attaching the helical strake structure with a reasonable geometrical configuration (such as the appropriate strake height, strake pitch, the number of starts and strake coverages) to the flexible riser. The effect is also diverse at different reduced velocity (Ur). The remarkable effect is found at Ur = l for the short riser, with about 97% reduction in the transverse vibration response.

关键词： Vortex-induced vibration (VIV) fluid structure interaction (FSI) Two-way coupling Helical strakes SST-SAS

Burning Numbers of Barbells

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2024年第2期40卷 526-538页

作者： Hui-qing LIU rui-ting ZHANG xiao-lan HU Hubei Key Laboratory of Applied Mathematics&Faculty of Mathematics and Statistic Hubei UniversityWuhan 430062China Hubei Key Laboratory of Mathematical Sciences&School of Mathematics and Statistics Central China Normal UniversityWuhan 430079China

Motivated by a discrete-time process intended to measure the speed of the spread of contagion in a graph,the burning number b(G)of a graph G,is defined as the smallest integer k for which there are vertices x1,…xk su... 详细信息

关键词： burning number short/long barbell isometric subtree cycle

Study on the influence of projectile on muzzle disturbance

在线全文

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2018年第5期14卷 570-577页

作者： Fei-fei Liu Yan-ming Song Hai-long Yu Wen-ding Lin Jie Zhang Zhi-hui Si Ming-kang Ding xiao-ting rui China Weapon Industry Corporation NHIC Nanjing Research Institute Nanjing210000China China Weapon Industry Corporation NHIC Baotou014000China Institute of Launch Dynamics Nanjing University of Science&TechnologyNanjing210094China

In order to make an efficient analysis of muzzle disturbance influenced by projectile mass, mass eccentricity, dynamic unbalance, load deviation, and clearance between projectile and bore, the orthogonal test method is extended to analyze the launch dynamics. Taking a tank as the research object, the launch dynamics equations of a tank system are established. Based on the stochastic simulation principle, the tank launch dynamic simulation system is constructed and through the development of the orthogonal test method, the influence of projectile on muzzle disturbance is studied. The study results provided both theoretical foundation and simulation approaches for improving the firing dispersion of the tank.

关键词： Muzzle disturbance Orthogonal test Projectile-barrel coupling Firing dispersion

Local tetragonal distortion of Pt alloy catalysts for enhanced oxygen reduction reaction efficiency

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第7期6卷 41-52页

作者： xiaoke Li xiao Duan Kang Hua Yongkang Wu Zhiyan rui rui Ding Aidong Li Chen Ouyang Jia Li ting Li Jianguo Liu National Laboratory of Solid-State Microstructures College of Engineering and Applied Sciencesand Collaborative Innovation Center of Advanced MicrostructuresNanjing UniversityNanjingChina Long-Life Fuel Cell Key Laboratory in Sichuan Province Dongfang Electric(Chengdu)Hydrogen Fuel Cell Technology Co.Ltd.ChengduChina Institute of Energy Power Innovation North China Electric Power UniversityBeijingChina

Platinum-based alloy nanoparticles are the most attractive catalysts for the oxygen reduction reaction at present,but an in-depth understanding of the relationship between their short-range structural information and catalytic performance is still ***,we present a synthetic strategy that uses transition-metal oxide-assisted thermal ***/C catalysts with localized tetragonal distortion were obtained by controlling the thermal diffusion process of transition-metal *** localized structural distortion induced a significant strain effect on the nanoparticle surface,which further shortened the length of the Pt-Pt bond,improved the electronic state of the Pt surface,and enhanced the performance of the ***/C catalysts with special short-range structures achieved excellent mass activity(2.27 Amg_(Pt)^(-1))and specific activity(3.34 A cm^(-2)).In addition,the localized tetragonal distortion-induced surface compression of the Pt skin improved the stability of the *** mass activity decreased by only 13%after 30,000 *** catalyst activity and excellent durability have also been demonstrated in the proton exchange membrane fuel cell *** study provides valuable insights into the development of advanced Pt-based nanocatalysts and paves the way for reducing noble-metal loading and increasing the catalytic activity and catalyst stability.

关键词： electrocatalysts fuel cells local tetragonal distortion oxygen reduction

A Review on the Mullins Effect in Tough Elastomers and Gels

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mechanica Solida Sinica 2024年第2期37卷 181-214页

作者： Lin Zhan Shaoxing Qu rui xiao MOE Key Lab of Disaster Forecast and Control in Engineering College of Mechanics and Construction EngineeringJinan UniversityGuangzhou510632China State Key Laboratory of Fluid Power and Mechatronic System Key Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceDepartment of Engineering MechanicsZhejiang UniversityHangzhou310027China

Tough elastomers and gels have garnered broad research interest due to their wide-ranging potential ***,during the loading and unloading cycles,a clear stress softening behavior can be observed in many material systems,which is also named as the Mullins *** this work,we aim to provide a complete review of the Mullins effect in soft yet tough materials,specifically focusing on nanocomposite gels,double-network hydrogels,and multi-network *** first revisit the experimental observations for these soft *** then discuss the recent developments of constitutive models,emphasizing novel developments in the damage mechanisms or network *** phenomenological models will also be briefly *** attention is then placed on the anisotropic and multiaxial modeling *** is demonstrated that most of the existing models fail to accurately predict the multiaxial data,posing a significant challenge for developing future anisotropic models tailored for tough gels and elastomers.

关键词： Mullins effect Double-network hydrogels Nanocomposite gels Multi-network elastomers Anisotropic damage model Multiaxial model

Hepatocyte growth factor promotes retinal pigment epithelium cell activity through MET/AKT signaling pathway

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Ophthalmology(English edition) 2024年第5期17卷 806-814页

作者： Si-rui Zhou Yu-Sheng Zhu Wen-ting Yuan xiao-Yan Pan Tong Wang xiao-Dong Chen Faculty of Life Sciences and Medicine Northwest UniversityXi’an 710069Shaanxi ProvinceChina First Affiliated Hospital of Northwest University Northwest UniversityXi’an 710069Shaanxi ProvinceChina Department of Ophthalmology Xi’an No.1 HospitalXi’an 710002Shaanxi ProvinceChina Shaanxi Institute of Ophthalmology Shaanxi Provincial Key Lab of OphthalmologyClinical Research Center for Ophthalmology Diseases of Shaanxi ProvinceXi’an 710002Shaanxi ProvinceChina

AIM:To explore the effects of hepatocyte growth factor(HGF)on retinal pigment epithelium(RPE)cell ***:The human adult retinal pigment epithelial cell line-19(ARPE-19)were treated by HGF or mesenchymalepithelial transition factor(MET)inhibitor SU11274 in *** viability was detected by a Cell Counting Kit-8 *** proliferation and motility was detected by a bromodeoxyuridine incorporation assay and a wound healing assay,*** expression levels of MET,phosphorylated MET,protein kinase B(AKT),and phosphorylated AKT proteins were determined by Western blot *** MET and phosphorylated MET proteins were also determined by immunofluorescence ***:HGF increased ARPE-19 cells’viability,proliferation and migration,and induced an increase of phosphorylated MET and phosphorylated AKT ***11274 significantly reduced cell viability,proliferation,and migration and decreased the expression of MET and AKT ***11274 suppressed HGF-induced increase of viability,proliferation,and migration in ARPE-19 ***,SU11274 also blocked HGF-induced phosphorylation of MET and AKT ***:HGF enhances cellular viability,proliferation,and migration in RPE cells through the MET/AKT signaling pathway,whereas this enhancement is suppressed by the MET inhibitor ***-induced MET/AKT signaling might be a vital contributor of RPE cells survival.

关键词： hepatocyte growth factor mesenchymal epithelial transition factor SU11274 retinal pigment epithelial cells