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Science china(Technological Sciences) 2009年第8期52卷 2424-2431页

作者： huang zhilong1,2.& jin xiaoling1 1 department of mechanics, Zhejiang University,{2., china 2.The State Key Laboratory of Fluid Power Transmission and Control, Zhejiang University,{2., china department of mechanics Zhejiang University Hangzhou 310027 China The State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

A new procedure is proposed to construct strongly nonlinear systems of multiple degrees of freedom subjected to parametric and/or external Gaussian white noises, whose exact stationary solutions are independent of energy. Firstly, the equivalent Fokker-Planck-Kolmogorov (FPK) equations are derived by using exterior differentiation. The main difference between the equivalent FPK equation and the original FPK equation lies in the additional arbitrary antisymmetric diffusion matrix. Then the exact stationary solutions and the structures of the original systems can be obtained by using the coefficients of antisymmetric diffusion matrix. The obtained exact stationary solutions, which are generally independent of energy, are for the most general class of strongly nonlinear stochastic systems multiple degrees of freedom (MDOF) so far, and some classes of the known ones dependent on energy belong to the special cases of them.

关键词： exact stationary solution nonlinear stochastic system equivalent system independent of energy

Stochastic stability of quasi-integrable Hamiltonian systems with time delay by using Lyapunov function method

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Science china(Technological Sciences) 2010年第3期53卷 703-712页

作者： LING Quan 1,jin xiaoling 1 &{2. {2. 2.1 department of mechanics,Zhejiang University,hangzhou 31002.,china 2.State Key Laboratory of Fluid Power Transmission and Control,Zhejiang University,hangzhou 31002.,china 1. department of mechanics Zhejiang University Hangzhou 310027 China2. State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

The asymptotic Lyapunov stability of one quasi-integrable Hamiltonian system with time-delayed feedback control is studied by using Lyapunov functions and stochastic averaging ***,a quasi-integrable Hamiltonian system with time-delayed feedback control subjected to Gaussian white noise excitation is approximated by a quasi-integrable Hamiltonian system without time ***,stochastic averaging method for quasi-integrable Hamiltonian system is used to reduce the dimension of the original system,and after that the Lyapunov function of the averaged It equation is taken as the optimal linear combination of the corresponding independent first integrals in ***,the stability of the system is determined by using the largest eigenvalue of the linearized *** examples are used to illustrate the proposed procedure and the effects of delayed time on the Lyapunov stability are discussed as well.

关键词： Lyapunov stability Lyapunov function time delay stochastic averaging

Quantum phase transition of the Jaynes-Cummings model

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Science china(Physics,mechanics & Astronomy) 2024年第1期67卷 1-9页

作者： Cheng Liu jin-Feng huang Key Laboratory of Low-Dimensional Quantum Structures and Quantum Control of Ministry of Education Key Laboratory for Matter Microstructure and Function of Hunan ProvinceDepartment of Physics and Synergetic Innovation Center for Quantum Effects and ApplicationsInstitute of Interdisciplinary StudiesHunan Normal UniversityChangsha 410081China

Herein,we propose an experimentally feasible scheme to show the quantum phase transition of the Jaynes-Cummings(JC)model by modulating the transition frequency of a two-level system in a quantum Rabi model with strong *** tuning the modulation frequency and amplitude,the ratio of the effective coupling strength of the rotating terms to the effective cavity(atomic transition)frequency can enter the deep-strong coupling regime,while the counter-rotating terms can be ***,a deep-strong JC model is *** ratio of the coupling strength to resonance frequencies in the deep-strong JC model is two orders of magnitude larger than the corresponding ratio in the original quantum Rabi *** scheme can be employed in atom-cavity resonance and off-resonance cases,and it is valid over a broad *** nonzero average cavity photons of the ground state indicate the emergence of a quantum phase ***,we demonstrate the dependence of the phase diagram on the atom-cavity detuning and modulation *** the parameters used in our scheme are within the reach of current experimental *** scheme provides a new mechanism for investigating the critical phenomena of finite-sized systems without requiring classical field limits,thereby opening a door for studying fundamental quantum phenomena occurring in the ultrastrong and even deep-strong coupling regimes.

关键词： Jaynes-Cummings model quantum phase transition frequency modulation

Testing the first law of black hole mechanics with gravitational waves

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Science china(Physics,mechanics & Astronomy) 2024年第10期67卷 76-82页

作者： Chao-Wan-Zhen Wang jin-Bao Zhu Guo-Qing huang Fu-Wen Shu department of Physics Nanchang UniversityNanchang 330031China Center for Relativistic Astrophysics and High Energy Physics Nanchang UniversityNanchang 330031China GCAP-CASPER Physics DepartmentBaylor UniversityWaco 76798-7316USA

The successful observation of gravitational waves has provided humanity with an additional method to explore the universe,particularly black *** this study,we utilize data from LIGO and Virgo gravitational wave observations to test the first law of black hole mechanics,employing two different *** consider the secondary compact object as a perturbation to the primary black hole before the merger,and the remnant black hole as a stationary black hole after the *** the pre-merger and post-merger analysis,our results demonstrate consistency with the first law,with an error level of approximate 2.%at a68%credibility level for *** the full inspiral-merger-ringdown analysis,our results show consistency with the first law of black hole mechanics,with an error level of about 6%at a 68%credibility level and 10%at a 95%credibility level for ***,we observe that the higher the mass ratio of the gravitational wave source,the more consistent our results are with the first law of black hole ***,our study sheds light on the nature of compact binary coalescence and their implications for black hole mechanics.

关键词： gravitational waves black hole mechanics data analysis ringdown

First-principles calculations on implanted TiO_2.by 3d transition metal ions

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Science china(Physics,mechanics & Astronomy) 2009年第6期52卷 838-842页

作者： HOU XingGang1,2. huang MeiDong1, WU xiaoling{2. LIU AnDong2.1 {2. of Physics, Tianjin Normal University, Tianjin 300387, china 2.Key Laboratory of Beam Technology and Material Modification of Ministry of Education, Beijing Normal University, Beijing 100875, china department of Physics Tianjin Normal University Tianjin 300387 China Key Laboratory of Beam Technology and Material Modification of Ministry of Education Beijing Normal University Beijing 100875 China

3d transition metal (V, Cr and Fe) ions are implanted into TiO2.by the method of metal ion implantation. The electronic band structures of TiO2.films doped 3d transition metal ions have been analyzed by ab initio band calculations based on a self-consistent full-potential linearized augmented plane-wave method within the first-principle formalism. Influence of implantation on TiO2.films is examined by the method of UV-visible spectrometry. The results of experiment and calculation show that the optical band gap of TiO2.films is narrowed by ion implantation. The calculation shows that the 3d state of V, Cr and Fe ions plays a significant role in red shift of UV-Vis absorbance spectrum.

关键词： 3d transition metal ions implantation TiO2 FP-LAPW electronic structure

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适用于钢丝毛刷的非对称鬃毛模型及应用

固体力学学报 2024年第4期45卷 477-487页

作者：钟炜翔金永斌金肖玲鲍荣浩黄志龙浙江大学航空航天学院杭州310000

本文针对钢丝毛刷表现出的方向依赖性摩擦现象(非对称摩擦),提出了一种基于鬃毛模型和LuGre模型的非对称鬃毛模型,其摩擦力由非对称刷毛与被接触基底之间水平方向相互无摩擦接触产生的.数值模拟和实验研究表明:非对称鬃毛模型能很好地... 详细信息

本文针对钢丝毛刷表现出的方向依赖性摩擦现象(非对称摩擦),提出了一种基于鬃毛模型和LuGre模型的非对称鬃毛模型,其摩擦力由非对称刷毛与被接触基底之间水平方向相互无摩擦接触产生的.数值模拟和实验研究表明:非对称鬃毛模型能很好地说明方向依赖性摩擦现象,并在平面双足机器人的仿真研究中发现,与对称摩擦模型相比,此模型能提高机器人最大运动速度.此外,实验研究表明钢丝毛刷相比于橡胶材质具有高摩擦、高耐磨等优势.基于这些特性,钢丝毛刷结构在足式机器人领域有着较大的应用前景和潜在优势.

关键词：非对称摩擦鬃毛模型 LuGre模型平面双足机器人

First-passage failure of MDOF nonlinear oscillator

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Science china(Technological Sciences) 2011年第8期54卷 1999-2006页

作者： XU Ming jin xiaoling {2. {2. department of mechanics Zhejiang University Hangzhou 310027 China

First-passage failure of multiple-degree-of-freedom nonlinear oscillators with lightly nonlinear dampings and strongly nonlinear stiffness subject to additive and/or parametric Gaussian white noise excitations is studied. First, by using the stochastic averaging method based on the generalized harmonic functions, the averaged It stochastic differential equation for the amplitudes of the nonlinear oscillators can be derived. Then the associated backward Kolmogorov equation of the conditional reliability function is established, and the conditional reliability is approximately expressed as a series expansion in terms of Kummer functions with time-dependent coefficients. By using the Galerkin method, the time dependent coefficients of the associated conditional reliability function can be solved by a set of differential equations. Finally, the proposed procedure is applied to Duffing-Van der Pol systems under external and/or parametric excitations of Gaussian white noises. The results are also verified by those obtained from Monte Carlo simulation of the original system. The effects of system parameters on first-passage failure are discussed briefly.

关键词： first-passage stochastic averaging method generalized harmonic function Kummer function Galerkin method

Nano-frictional mechano-reinforcing porous nanowires scaffolds

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Friction 2024年第5期12卷 968-980页

作者： Licheng HUA Conghu HU jingkang ZHANG jin LI Chenjie GU Bin {2. Guangyong LI Jianke DU Wanlin GUO Smart Materials and Advanced Structures Laboratory School of Mechanical Engineering&MechanicsNingbo UniversityNingbo315211China Key Laboratory for Intelligent Nano Materials and Devices of Ministry of Education Nanjing University of Aeronautics and AstronauticsNanjing210016China Key Laboratory of Impact and Safety Engineering Ministry of EducationSchool of mechanical Engineering and MechanicsNingbo UniversityNingbo315211China department of Microelectronics and Engineering Ningbo UniversityNingbo315211China

Artificial biomaterials with dynamic mechano-responsive behaviors similar to those of biological tissues have been drawing great *** this study,we report a TiO_(2.-based nanowire(TiO_(2.NWs)scaffolds,which exhibit dynamic mechano-responsive behaviors varying with the number and amplitude of nano-deformation *** is found that the elastic and adhesive forces in the TiO_(2.NWs scaffolds can increase significantly after multiple cycles of *** nanofriction experiments show the triboelectric effect of increasing elastic and adhesive forces during the nano-deformation cycles of TiO_(2.NWs *** properties allow the TiO_(2.NW scaffolds to be designed and applied as intelligent artificial biomaterials to simulate biological tissues in the future.

关键词： TiO_(2.NWs scaffolds nano-deformation mechano-reinforcing triboelectric effect intelligent artificial biomaterials

FIRST-PASSAGE FAILURE OF PREISACH HYSTERETIC SYSTEMS

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Acta Mechanica Solida Sinica 2014年第5期27卷 477-485页

作者： Ming Xu xiaoling jin Yong Wang {2. {2. Institute of Fluid mechanics China Jiliang University department of Engineering mechanics Zhejiang University

The first-passage failure of a single-degree-of-freedom hysteretic system with non- local memory is investigated. The hysteretic behavior is described through a Preisach model with excitation selected as Gaussian white noise. First, the equivalent nonlinear non-hysteretic sys- tem with amplitude-dependent damping and stiffness coefficients is derived through generalized harmonic balance technique. Then, equivalent damping and stiffness coefficients are expressed as functions of system energy by using the relation of amplitude to system energy. The stochastic aver- aging of energy envelope is adopted to accept the averaged It5 stochastic differential equation with respect to system energy. The establishing and solving of the associated backward Kolmogorov equation yields the reliability function and probability density of first-passage time. The effects of system parameters on first-passage failure are investigated concisely and validated through Monte Carlo simulation.

关键词： first-passage failure Preisach hysteretic systems stochastic averaging of energyenvelope generalized harmonic balance technique

Optimal bounded control for maximizing reliability of Duhem hysteretic systems

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Applied Mathematics and mechanics(English Edition) 2015年第10期36卷 1337-1346页

作者： Ming XU xiaoling jin Yong WANG {2. {2. College of Metrology and Measurement Engineering China Jiliang University department of Engineering mechanics Zhejiang University

The optimal bounded control of stochastic-excited systems with Duhem hysteretic components for maximizing system reliability is investigated. The Duhem hysteretic force is transformed to energy-depending damping and stiffness by the energy dissipation balance technique. The controlled system is transformed to the equivalent non- hysteretic system. Stochastic averaging is then implemented to obtain the It5 stochastic equation associated with the total energy of the vibrating system, appropriate for eval- uating system responses. Dynamical programming equations for maximizing system re- liability are formulated by the dynamical programming principle. The optimal bounded control is derived from the maximization condition in the dynamical programming equation. Finally, the conditional reliability function and mean time of first-passage failure of the optimal Duhem systems are numerically solved from the Kolmogorov equations. The proposed procedure is illustrated with a representative example.

关键词： optimal bounded control reliability Duhem hysteretic system stochastic dynamical programming principle