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Quasi-shadowing Property on Random Partially Hyperbolic Sets

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Acta Mathematica Sinica,English Series 2018年第9期34卷 1429-1444页

作者： Lin wang Xin Sheng WANG Yu Jun ZHU School of Applied Mathematics Shanxi University of Finance and Economics Taiyuan 030006 P. R. China College of Mathematics and Information Science Hebei Normal University Shijiazhuang 050024 P. R. China School of Mathematical Sciences Xiamen University Xiamen 361005 P. R. China

Abstract In this paper we investigate the quasi-shadowing property for C1 random dynamical sys-terns on their random partially hyperbolic sets. It is shown that for any pseudo orbit {xk}＋∞ -∞ on a random partially hyperbolic set there exists a ＂center＂ pseudo orbit {Yk}＋∞ -∞ shadowing it in the sense that yk＋l is obtained from the image of yk by a motion along the center direction. Moreover, when the random partially hyperbolic set has a local product structure, the above ＂center＂ pseudo orbit{yk}＋∞ -∞ can be chosen such that yk＋1 and the image of yk lie in their common center leaf.

关键词： Quasi-shadowing property random partially hyperbolic set local product structure

On Local Constancy of Topological Entropy for Certain Partially Hyperbolic Diffeomorphisms

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Acta Mathematicae Applicatae Sinica 2018年第2期34卷 249-253页

作者： Lin wang xin-sheng wang Yu-jun ZHU College of Applied Mathematics Shanxi University of Finance and Economics Taiyuan 030006 China College of Mathematics and Information Science Hebei Normal University Shijiazhuang 050024 China School of Mathematical Sciences Xiamen University Xiarnen 361005 China

Let f ： M → M be a partially hyperbolic diffeomorphism on a closed Riemannian manifold with uniformly compact center foliation. We show that if the center foliation of f is of dimension one then the topological entr... 详细信息

关键词： partially hyperbolic diffeomorphism topological entropy local constancy

Investigation on strong nonlinear interactions between underwater explosion and water surface based on compressible multiphase flow with phase transition

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Journal of Hydrodynamics 2023年第2期35卷 351-364页

作者： Jun Yu Hai-kun wang Zhen-xin sheng Yi Hao China Ship Scientific Research Center Wuxi214082China Taihu Laboratory of Deep-sea Technological Science Wuxi214082China

The strong nonlinear interactions between underwater explosion and water surface were numerically investigated using a phase transition model based on a four-equation system,which can deal with the complex deformable interface among different phases,including water,air,explosion bubble,and cavitation.The numerical method is verified by comparing the numerical results with experimental results,and good agreements are found.This study considers an ideal sine wave for simulating the shape of water surface.Two examples of different detonation depths of charge are investigated.In each example,the first case is the basic simulation without surface wave,and the other three cases are the simulations with sine waves of different wavelengths.Unique characteristics of the interactions,such as shock wave propagation,explosion bubble expansion,and the generation,development,and collapse of cavitation,are observed in the numerical simulations.By capturing the detailed density and pressure contours during the interaction process,we can better understand the underlying mechanisms of the explosion bubble,cavitation,and surface waves.These numerical results demonstrate that geometric nonlinearity impacts cavitation evolution and the explosion bubble movement mechanism.Additionally,the secondary cavitation phenomenon has been found in the cases without surface wave,and its fundamental physical mechanism is presented in detail.The present results can expand the existing database of multiphase flow in the underwater explosion and provide an insight into the strong nonlinear interaction between the underwater explosion and water surface.

关键词： Underwater explosion compressible multiphase flow phase transition model cavitation water surface

A fault diagnosis model based on weighted extension neural network for turbo-generator sets on small samples with noise

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Chinese Journal of Aeronautics 2020年第10期33卷 2757-2769页

作者： Tichun wang Jiayun wang Yong WU xin sheng College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China Department of Business Strategy and Innovation Griffith UniversityGold Coast CampusQLD 4222Australia School of Business Jiangsu Open UniversityNanjing 210036China

In data-driven fault diagnosis for turbo-generator sets,the fault samples are usually expensive to obtain,and inevitably with noise,which will both lead to an unsatisfying identification performance of diagnosis models.To address these issues,this paper proposes a fault diagnosis model for turbo-generator sets based on Weighted Extension Neural Network(W-ENN).WENN is a novel neural network which has three types of connection weights and an improved correlation function.The performance of the proposed model is validated against Extension Neural Network(ENN),Support Vector Machine(SVM),Relevance Vector Machine(RVM)and Extreme Learning Machine(ELM)based models.The results indicate that,on noisy small sample sets,the proposed model is superior to the other models in terms of higher identification accuracy with fewer samples and strong noise-tolerant ability.The findings of this study may serve as a powerful fault diagnosis model for turbo-generator sets on noisy small sample sets.

关键词： Fault diagnosis Samples with noise Small samples learning Turbo-generator sets Weighted Extension Neural Network

Flexible sodium-ion capacitors boosted by high electrochemicallyreactive and structurally-stable Sb_(2)S_(3)nanowire/Ti_(3)C_(2)Tx MXene film anodes

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Nano Research 2023年第4期16卷 5592-5600页

作者： Jian Yang Tianyi wang xin Guo Xiaoxue sheng Jiabao Li Chengyin wang Guoxiu wang Institute for Innovative Materials and Energy Faculty of Chemistry and Chemical EngineeringYangzhou UniversityYangzhou 225002China Centre for Clean Energy Technology School of Mathematics and PhysicsFaculty of ScienceUniversity of Technology SydneySydneyNSW 2007Australia

The rapid development of portable,foldable,and wearable electronic devices requires flexible energy storage systems.Sodiumion capacitors(SICs)combining the high energy of batteries and the high power of supercapacitors are promising solutions.However,the lack of flexible and durable electrode materials that allow fast and reversible Na+storage hinders the development of flexible SICs.Herein,we report a high-capacity,free-standing and flexible Sb2S3/Ti_(3)C_(2)Tx composite film for fast and stable sodium storage.In this hybrid nano-architecture,the Sb_(2)S_(3)nanowires uniformly anchored between Ti_(3)C_(2)Tx nanosheets not only act as sodium storage reservoirs but also pillar the two-dimensional(2D)Ti_(3)C_(2)Tx to form three-dimensional(3D)channels benefiting for electrolyte penetration.Meanwhile,the highly conductive Ti_(3)C_(2)Tx nanosheets provide rapid electron transport pathways,confine the volume expansion of Sb_(2)S_(3)during sodiation,and restrain the dissolution of discharged sodium polysulfides through physical constraint and chemical absorption.Owing to the synergistic effects of the one-dimensional(1D)Sb_(2)S_(3)nanowires and 2D MXenes,the resultant composite anodes exhibit outstanding rate performance(553 mAh·g−1 at 2 A·g−1)and cycle stability in sodium-ion batteries.Moreover,the flexible SICs using Sb2S3/Ti_(3)C_(2)Tx anodes and active carbon/reduced graphene oxide(AC/rGO)paper cathodes deliver a superior energy and power density in comparison with previously reported devices,as well as an excellent cycling performance with a high capacity retention of 82.78%after 5,000 cycles.This work sheds light on the design of next-generation low-cost,flexible and fast-charging energy storage devices.

关键词： MXene Sb_(2)S_(3)nanowires flexible energy storage devices sodium-ion batteries sodium-ion capacitors

Investigation on bonding interfaces of an SA508 steel billet manufactured by additive forging

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Journal of Iron and Steel Research(International) 2022年第12期29卷 2016-2023页

作者： xin-jin Zhang Tian-sheng wang Zhi-chao Zhu Lin Zhu State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao 066004HebeiChina China First Heavy Industries Co. Ltd.Qiqihaer 161042HeilongjiangChina

An experimental steel billet of SA508 reactor pressure vessel material was manufactured by the additive forging method,and microstructure and mechanical properties of the hot-compression bonding interface were systematically investigated.The result indicated that oxidation levels of bonding interfaces were well controlled using vacuum electron beam welding.It was easy to discriminate interfaces from base materials during the optical microstructure observation,since interfaces were characterized by grain or phase boundaries in a straight line.Test results of uniaxial tensile experiments(at 20 and 350°C)and Charpy V-notched impact tests(at 0 and 20°C)showed that fracture behaviour of all those samples appeared at the base material,and bonding interfaces showed advantage of strength and toughness at the forge bonding state.

关键词： Reactor pressure vessel Additive forging Interfacial microstructure Mechanical property

Breeding against mycorrhizal symbiosis:Modern cotton (Gossypium hirsutum L.) varieties perform more poorly than older varieties except at very high phosphorus supply levels

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Journal of Integrative Agriculture 2023年第3期22卷 701-715页

作者： wang xin-xin ZHANG Min sheng Jian-dong FENG Gu Thomas W.KUYPER College of Resources and Environmental Sciences China Agricultural UniversityBeijing 100193P.R.China State Key Laboratory of North China Crop Improvement and Regulation/Mountain Area Research Institute Hebei Agricultural UniversityBaoding 071001P.R.China College of Resource and Environmental Sciences Xinjiang Agricultural UniversityUrumqi 830052P.R.China Soil Biology Group Wageningen University&ResearchWageningen 6700AAThe Netherlands

Cotton (Gossypium hirsutum L.) is an importantfiber cash crop,but its root traits related to phosphorus (P) acquisition,including mycorrhizal root traits,are poorly understood.Eight cotton varieties bred in northwestern China that were released between 1950 and 2013 were grown in pots with or without one arbuscular mycorrhizal fungal (AMF) species(Funneliformis mosseae) at three P supply levels (0,50 and 300 mg P as KH_(2)PO_(4)kg^(-1)).Eleven root traits were measured and calculated after 7 wk of growth.The more recent accessions had smaller root diameters,acquired less P and produced less biomass,indicating an (inadvertent) varietal selection for thinner roots that provided less cortical space for AMF,which then increased the need for a high P fertilizer level.At the two lower P levels,the mycorrhizal plants acquired more P and produced more biomass than non-mycorrhizal plants (3.2 vs.0.9 mg P per plant;1.8 vs.0.9 g biomass per plant at P_(0);14.5 vs.1.7 mg P per plant;and 4.7 vs.1.6 g biomass per plant at P_(50)).At the highest P level,the mycorrhizal plants acquired more P than non-mycorrhizal plants (18.8 vs.13.4 mg per P plant),but there was no difference in biomass (6.2 vs.6.3 g per plant).At the intermediate P level,root diameter was significantly positively correlated with shoot biomass,P concentration and the P content of mycorrhizal plants.The results of our study support the importance of the outsourcing model of P acquisition in the root economics space framework.Inadvertent varietal selection in the last decades,resulting in thinner roots and a lower benefit from AMF,has led to a lower productivity of cotton varieties at moderate P supply (i.e.,when mycorrhizal,the average biomass of older varieties 5.0 g per plant vs.biomass of newer varieties 4.4 g per plant),indicating the need to rethink cotton breeding efforts in order to achieve high yields without very high P input.One feasible way to solve the problem of inadvertent varietal selection for cotton is to be aware of the trade-offs between the r

关键词： cotton varieties plant breeding arbuscular mycorrhizal fungi root economics space outsourcing phosphorus acquisition

Preparation of porous titanium materials by powder sintering process and use of space holder technique

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Journal of Iron and Steel Research(International) 2017年第1期24卷 97-102页

作者： xin-sheng wang Zhen-lin Lu Lei Jia Jiang-xian Chen School of Materials Science and Engineering Xi'an University of TechnologyXi'an 710048ShaanxiChina

It is shown that an adapted powder sintering process can successfully prepare a 24.0%-35.5% porous titanium composite using 20μm Ti powder and rice husk particles ranging in size between 250μm and600μm.The phase constituents of the porous Ti composite samples were determined by X-ray diffraction（XRD）pattern sintered at 1250℃.The generation of silicon in the form of a TiSi2 solid solution,injected into the substrate,illustrates the solid solution strengthening effect.The average grain size of the tested sample and the grain boundary area increase along with the silicon content.This indicates that silicon is dispersed within the green compact of Ti.As the distance from a hole becomes greater,the nanohardness increases until it reaches a maximum hardness of 3.5GPa at approximately 1.5mm.This may be due to the solid solution strengthening of SiO2.However,nanohardness is 3.3GPa at a distance of approximately 0.5mm from a hole′s edge.The compressive strength is measured to be in the range of 440-938 MPa.The strain reaches 14.8%-16.6% under compression testing.A large number of cleavage steps appear following a fracture.The observed fracture is a brittle fracture.Porous Ti composites with about 36% porosity have promising potential biomaterial applications,specifically related to bone implants and biological bearings.

关键词： Rice husk Porous Ti Sintering Porosity Hardness Mechanical property

Dynamic recrystallization behavior and microstructure evolution of high-performance Cu-3.28Ni-0.6Si-0.22Zn-O.11Cr-0.04P during hot compression

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Rare Metals 2021年第1期40卷 156-167页

作者： Chang-sheng wang Hua-Dong Fu Jian-xin Xie Beijing Advanced Innovation Center for Materials Genome Engineering Institute for Advanced Materials and TechnologyUniversity of Science and Technology BeijingBeijing 100083China Beijing Laboratory of Metallic Materials and Processing for Modern Transportation Institute for Advanced Materials and TechnologyBeijing 100083China

By means of isothermal compression at temperatures in the range of 650-900℃and strain rates in the range of 0.001-1 s^(-1),the dynamic recrystallization behavior and microstructural evolution of a Cu-3.28 Ni-0.6 Si-0.22 Zn-0.11 Cr-0.04 P(wt%)alloy designed by a machine learning method were investigated.A semiempirical constitutive equation,processing maps and an average activation energy were generated.The microstructure under different conditions and the effect of strain rate on the texture of the alloy at 800-900℃were observed.The results show that the suitable temperature is800-900℃;when the strain is less than 0.4,the appropriate strain rate is 0.01-0.5 s^(-1);and when the strain is greater than 0.4,the appropriate strain rate is below0.05 s^(-1).After deformation at 800℃,the main texture changed from{112}of copper to a uniform distribution with the increase in strain rate,but the sample did not have obvious texture after deformation at 850 and900℃.The above results can provide a reference for the selection of process parameters.

关键词： High-performance copper alloy Hot compression Dynamic recrystallization Processing map Texture evolution