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Semi-uniform Sub-additive Ergodic Theorems for Skew-product Quasi-flows

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Acta Mathematicae Applicatae Sinica 2014年第2期30卷 359-366页

作者： jin-ling zhou Institute of Applied Mathematics Academy of Mathematics and Systems SciencesChinese Academy of Sciences

The aim of this paper is to extend the semi-uniform ergodic theorem and semi-uniform sub-additive ergodic theorem to skew-product quasi-flows. Furthermore, more strict inequalities about these two theorems are established. By making use of these results, it is feasible to get uniform estimation of the Lyapunov exponent of some special systems even under non-uniform hypotheses

关键词： semi-uniform sub-additive ergodic theorem skew-product quasi-flows

Modeling and Validation of Diamagnetic Rotor Levitated by Permanent Magnetics

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 224-235页

作者： Yuanping Xu Yue Zhang jin zhou Chaowu jin College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

As an innovative,low-power consuming,and low-stiffness suspension approach,the diamagnetic levitation technique has attracted considerable interest because of its potential applicability in miniaturized mechanical *** foundation of a diamagnetic levitation system is mathematical modeling,which is essential for operating performance optimization and stability ***,few studies on systematic mathematical modeling have been *** this study,a systematic mathematical model for a disc-shaped diamagnetically levitated rotor on a permanent magnet array is *** on the proposed model,the magnetic field distribution characteristics,diamagnetic levitation force characteristics(i.e.,levitation height and stiffness),and optimized theoretical conditions for realizing stable levitation are *** are conducted to verify the feasibility of the proposed mathematical *** predictions and experimental results indicate that increasing the levitation height enlarges the stable ***,with a further increase in the rotor radius,the stable regions of the rotor gradually diminish and even ***,when the levitation height is fixed,a moderate rotor radius permits stable *** study proposes a mathematical modeling method for a diamagnetic levitation system that has potential applications in miniaturized mechanical systems.

关键词： Diamagnetic levitation Magnetic levitation Rotor Modeling Validation Stability

Characterization of a Novel Annexin Gene from Cotton (Gossypium hirsutum cv CRI 35) and Antioxidative Role of its Recombinant Protein

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Journal of Integrative Plant Biology 2011年第5期53卷 347-357页

作者： Lu zhou jin Duan Laboratory of Molecular Biology and MOE Laboratory of Protein Science School of Life Sciences Tsinghua University Beijing 100084China

Plant annexins represent a multigene family involved in cellular elongation and development. A cDNA encoding a novel annexin was isolated from a cotton （Gossypium hirsutum） fiber cDNA library and designated GhAnxl. This gene encodes a 316 amino acid protein with a theoretical molecular mass of 36.06 kDa and a theoretical pl of 6.19. At the amino acid level, it shares high sequence similarity and has evolutionary relationships with annexins from higher plants. The purified recombinant protein expressed in Escherichia coil was used to investigate its physicochemical properties. Circular dichroism spectrum analyses showed a positive peak rising to the maximum at 196 nm and a broad negative band rounding 215 nm, suggesting that the GhAnxl protein was prominently α-helical. The fluorescence measurements indicated that it could bind to Ca2 in vitro. These results demonstrated that GhAnxl was a typical annexin protein in cotton. A bioassay experiment was conducted to analyze its potential function and showed that E. coil cells expressing GhAnxl were protected from tert-butyl hydroperoxide （tBH） stress, suggesting that it had a potential antioxidative role. Northern blot analyses revealed that GhAnxl was highly expressed in fibers, especially during the elongation stage, suggesting that it might be important for fiber elongation.

关键词： LIPOCORTINS RECOMBINANT proteins ANTIOXIDANTS COTTON GENETICS ANTISENSE DNA PLANT bioassay AMINO acid sequence

Synchronization of networked multibody systems using fundamental equation of mechanics

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Applied Mathematics and Mechanics(English Edition) 2016年第5期37卷 555-572页

作者： Jun LIU jinchen JI jin zhou Shanghai Institute of Applied Mathematics and Mechanics Shanghai UniversityShanghai 200072China Department of Mathematics Jining UniversityQufu 273155Shandong ProvinceChina Faculty of Engineering and Information Technology University of Technology SydneyNSW 2007Australia Shanghai Key Laboratory of Mechanics in Energy Engineering Shanghai 200072China

From the analytical dynamics point of view, this paper develops an optimal control framework to synchronize networked multibody systems using the fundamental equation of mechanics. A novel robust control law derived from the framework is then used to achieve complete synchronization of networked identical or non-identical multibody systems formulated with Lagrangian dynamics. A distinctive feature of the developed control strategy is the introduction of network structures into the control requirement. The control law consists of two components, the first describing the architecture of the network and the second denoting an active feedback control strategy. A corresponding stability analysis is performed by the algebraic graph theory. A representative network composed of ten identical or non-identical gyroscopes is used as an illustrative example. Numerical simulation of the systems with three kinds of network structures, including global coupling, nearest-neighbour, and small-world networks, is given to demonstrate effectiveness of the proposed control methodology.

关键词： fundamental equation of mechanics analytical dynamics synchronization,networked multibody system gyrodynamics coordinate control

Existence and Uniqueness of Stochastic Differential Equations with Random Impulses and Markovian Switching under Non-Lipschitz Conditions

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Acta Mathematica Sinica,English Series 2011年第3期27卷 519-536页

作者： Shu jin WU Bin zhou School of Finance and Statistics East China Normal University Shanghai 200241 P. R. China

In the paper, stochastic differential equations with random impulses and Markovian switching are brought forward, where the so-called random impulse means that impulse ranges are driven by a series of random variables and impulse times are a random sequence, so these equations extend stochastic differential equations with jumps and Markovian switching. Then the existence and uniqueness of solutions to such equations are investigated by employing the Bihari inequality under non-Lipschtiz conditions.

关键词： Stochastic differential equation random impulse Markovian switching existence uniqueness non-Lipschtiz condition

Strengthening mechanisms of reduced activation ferritic/martensitic steels:A review

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International Journal of Minerals,Metallurgy and Materials 2021年第3期28卷 335-348页

作者： jin-hua zhou Yong-feng Shen Nan Jia Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) School of Materials Science and EngineeringNortheastern UniversityShenyang 110819China The State Key Lab of Rolling&Automation Northeastern UniversityShenyang 110819China

This review summarizes the strengthening mechanisms of reduced activation ferritic/martensitic(RAFM)***-angle grain boundaries,subgrain boundaries,nano-sized M_(23)C_(6),and MX carbide precipitates effectively hinder dislocation motion and increase high-temperature strength.M23C6 carbides are easily coarsened under high temperatures,thereby weakening their ability to block *** properties are improved through the reduction of M23C6 ***,the loss of strength must be compensated by other strengthening *** review also outlines the recent progress in the development of RAFM *** dispersion-strengthened steels prevent M23C6 precipitation by reducing C content to increase creep life and introduce a high density of nano-sized oxide precipitates to offset the reduced *** plastic deformation methods can substantially refine subgrains and MX carbides in the *** thermal deformation strengthening of RAFM steels mainly relies on thermo-mechanical treatment to increase the MX carbide and subgrain *** procedure increases the creep life of TMT(thermo-mechanical treatment)9Cr-1W-0.06Ta steel by~20 times compared with those of F82H and Eurofer 97 steels under 550℃/260 MPa.

关键词： reduced activation ferritic/martensitic steel strengthening mechanism high-angle grain boundary subgrain boundary precipitate

Research on modeling and self-excited vibration mechanism in magnetic levitation-collision interface coupling system

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 873-890页

作者： jinghu TANG Chaofeng LI jin zhou Zhiwei WU School of Mechanical Engineering&Automation Northeastern UniversityShenyang 110819China Key Laboratory of Vibration and Control of Aero-Propulsion Systems of Ministry of Education of China Northeastern UniversityShenyang 110819China School of Mechanical and Electrical Engineering Nanjing University of Aeronautics and AstronauticsNanjing 210016China

The modeling and self-excited vibration mechanism in the magnetic levitation-collision interface coupling system are *** effects of the control and interface parameters on the system's stability are *** frequency range of self-excited vibrations is investigated from the energy point of *** phenomenon of self-excited vibrations is elaborated with the phase *** corresponding control strategies are briefly analyzed with respect to the vibration *** results show that when the levitation objects collide with the mechanical interface,the system's vibration frequency becomes larger with the decrease in the collision gap;when the vibration frequency exceeds the critical frequency,the electromagnetic system continues to provide energy to the system,and the collision interface continuously dissipates energy so that the system enters the self-excited vibration state.

关键词： magnetic levitation coupling system self-excited vibration mechanical interface vibration frequency

Analysis of the abnormal resistance in AlGaN/GaN heterostructure's ohmic contact tests

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Rare Metals 2007年第5期26卷 463-469页

作者： XU Chuan WANG jinyan jin Haiyan zhou jin WEN Cheng P Institute of Microelectronics Peking University Beijing 100871 China

Ti/Al/Ti/Au and Ti/Al/Ni/Au ohmic contacts were fabricated on AlGaN/GaN heterostructure under different temperatures of rapid thermal processing （RTP）. Since abnormal resistance values were observed during the contact resistance testing,the surface morphology and contact borders of the samples were analyzed to determine the physical mechanism. Such abnormal phenomenon is found to originate from cracking of the AlGaN layer during RTP,flowing of Ti/Al metallic liquid along the crevices,and continuous reaction of the metallic liquid with AlGaN/GaN. Such processes result in abnormal conduction channels. The possible mechanism of the crevice formation was discussed,and the possible solutions to avoid the crevices were proposed.

关键词： semiconductor technology abnormal resistance EDX AlGaN/GaN ohmic contact crevices

Effect of substrate elasticity on evaporation kinetics and evaporative deposition of aqueous polystyrene nanoparticles droplets

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Science China(Physics,Mechanics & Astronomy) 2020年第11期63卷 72-79页

作者： Ying-Song Yu Yi-Qi Zhu XianFu Huang jin-Zhi zhou An zhou Department of Mechanics School of Civil EngineeringArchitecture and EnvironmentHubei University of TechnologyWuhan 430068China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

Evaporation of aqueous polystyrene(PS)nanoparticles droplets on silicon and polydimethylsiloxane(PDMS)surfaces was *** results showed that softer PDMS surfaces yielded a longer constant contact radius(CCR)stage,which could be ascribed to surface deformation of PDMS induced by the vertical component of liquid-vapor interfacial *** depositions of nanoparticles with different crack patterns were found on both silicon and PDMS ***-situ observation of crack formation showed that nanoparticle movement on the silicon surface was impeded,resulting in radial cracks with periodic *** contrast,nanoparticles were shown to move easily on the PDMS *** observation indicated the difference in crack patterns on surfaces could be attributed to the friction force between nanoparticles and the substrate.A large friction force between nanoparticles and the substrate prevented cracks from moving,resulting in a radial crack pattern with periodic distribution,while a small friction force produced multiple large cracks.

关键词： droplet evaporation nanoparticle constant contact radius stage crack