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Acta Mechanica Solida Sinica 2017年第1期30卷 11-19页

作者： q.F.Lü M.L.Deng w.q.zhu Department of Mechanics State Key Laboratory of Fluid Power and Mechatronic SystemsKey Laboratory of Soft Machines and Smart Devices of Zhejiang ProvinceZhejiang University

A stochastic averaging method of quasi integrable and resonant Hamiltonian systems under excitation of fractional Gaussian noise （fGn） with the Hurst index 1/2 〈 H 〈 1 is proposed. First, the definition and the basic property of fGn and related fractional Brownian motion （iBm） are briefly introduced. Then, the averaged fractional stochastic differential equations （SDEs） for the first integrals and combinations of angle variables of the associated Hamiltonian systems are derived. The stationary probability density and statistics of the original systems are then obtained approximately by simulating the averaged SDEs numerically. An example is worked out to illustrate the proposed stochastic averaging method. It is shown that the results obtained by using the proposed stochastic averaging method and those from digital simulation of original system agree well.

关键词： quasi integrable and resonant Hamiltonian system Fractional Brownian motion Fractional Gaussian noise Stochastic averaging method Internal resonant

Reliability of quasi integrable and non-resonant Hamiltonian systems under fractional Gaussian noise excitation

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Acta Mechanica Sinica 2020年第4期36卷 902-909页

作者： q.F.Lu w.q.zhu M.L.Deng Department of Mechanics State-Key Laboratory of Fluid Power and Mechatronic SystemsZhejiang UniversityHangzhou 310027China

The reliability of quasi integrable and non-resonant Hamiltonian system under fractional Gaussian noise(fGn)excitation is *** rather flat fGn power spectral density(PSD)in most part of frequency band,the fGn is innovatively regarded as a wide-band ***,the stochastic averaging method for quasi integrable Hamiltonian systems under wide-band noise excitation is applied to reduce 2n-dimensional original system into n-dimensional averaged ltd stochastic differential equations(SDEs).Reliability function and mean first passage time are obtained by solving the associated backward Kolmogorov equation and Pontryagin *** validity of the proposed procedure is tested by applying it to an example and comparing the numerical results with those from Monte Carlo simulation.

关键词： Reliability Fkst passage time quasi integrable and non-resonant Hamiltonian systems Fractional Gauss noise

Interference Suppression and Jitter Elimination Ability-Based Adaption Tracking Guidance for Robotic Fishes

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IEEE/CAA Journal of Automatica Sinica 2025年第1期 126-137页

作者： Dongfang Li Jie Huang Rob Law Xin Xu Limin zhu Edmond q.wu IEEE the School of Electrical Engineering and Automation Fuzhou University the Key Laboratory of System Control and Information Processing Ministry of Education the School of Electrical Engineering and Automation Fuzhou University 5G+Industrial Internet Institute Fuzhou University the University of Macau the College of Mechatronics and Automation National University of Defense Technology the School of Mechanical Engineering Shanghai Jiao Tong University the Department of Computer Science and Engineering Shanghai Jiao Tong University

This work presents an adaptive tracking guidance method for robotic fishes. The scheme enables robots to suppress external interference and eliminate motion jitter. An adaptive integral surge line-of-sight guidance rule is designed to eliminate dynamics interference and sideslip issues. Limited-time yaw and surge speed observers are reported to fit disturbance variables in the model. The approximation values can compensate for the system's control input and improve the robots' tracking ***, this work develops a terminal sliding mode controller and third-order differential processor to determine the rotational torque and reduce the robots' run jitter. Then, Lyapunov's theory proves the uniform ultimate boundedness of the proposed method. Simulation and physical experiments confirm that the technology improves the tracking error convergence speed and stability of robotic fishes.

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SUBCONVERGENCE OF FINITE ELEMENTS AND A SELF-ADAPTIVE ALGORITHM

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Journal of Computational Mathematics 1996年第4期14卷 336-344页

作者： zhu, qD Lin, q SOUTHEAST UNIV DEPT MECH & MATHNANJINGPEOPLES R CHINA CHINESE ACAD SCI INST SYST SCIBEIJINGPEOPLES R CHINA

TENSILE STRESS RELAXATION OF TURBINE BOLT STEELS AT HIGH TEMPERATURE

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Acta Metallurgica Sinica(English Letters) 2004年第4期17卷 542-547页

作者： G.q.Jia H.w.Shen Y.M.zhu Metallurgical Department. Shanghai Turbine Company Ltd. Shanghai 200240 ChinaMetallurgical Department. Shanghai Turbine Company Ltd. Shanghai 200240 ChinaMetallurgical Department. Shanghai Turbine Company Ltd. Shanghai 200240 China

Stress relaxation behavior of two turbine bolt steels was evaluated by the manual-controlled tensile stress relaxation test (TSRT) at high temperature. First, feasibility and the procedure of the manual-controlled tensile stress relaxation test (TSRT) is discussed and carried out on a general creep testing machine. And then, the experimental results from such type of test were compared to the existing data provided by certain Laboratory U.K. Overall good agreement between the results of manual-controlled TSRT method and the existing data provides confidence in the use of the proposed method in practice. Finally, the experimental results of turbine bolt steels from TSRT were compared with that of bending test. It is observed that great difference exists between the results from two different type stress relaxation tests. It is therefore suggested that the results from TSRT method be adopted in turbine bolt design in engineering.

关键词： tensile stress-relaxation test bending stress-relaxation test turbine bolt steels

DECREASING PITTING SUSCEPTIBILITY OF PASSIVE FILMS ON X70 PIPELINE STEEL IN NaCl SOLUTIONS BY ILLUMINATION

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Acta Metallurgica Sinica(English Letters) 2006年第2期19卷 91-97页

作者： w.C. zhu w.H. Leng J.q. Zhang C.N. Cao Department of Chemistry Zhejiang University Hangzhou 310027 China State Key Laboratory for Corrosion and Protection of Metals Institute of Metal Research The Chinese Academy of Sciences Shenyang 110016 China

The influence of UV illumination on passivity and pitting susceptibility on X70 pipoeline steel in a borate buffer （pH=8.4 ） solution containing NaCl is described. It is observed that illumination of the sample leads to a decrease in its pitting susceptibility as indicated by pitting potential and incubation time measurements in chloride containing electrolytes. This effect is strongly dependent on the applied potential during passivation. The electronic properties of the passive films on X70 steel were studied by Mott-Schottky analysis and photocurrent transient measurements. The results indicated that illumination during passivation led to modifications in the electronic properties of the passive films, mainly to a decrease of the bulk doping and an increase in the surface state density. The cause for the decrease in the pitting susceptibility is preliminary explained in terms of such modifications of the passive flm.

关键词： X70 pipeline steel pitting susceptibility illumination passivation

Novel method for random vibration analysis of single-degree-of-freedom vibroimpact systems with bilateral barriers

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Applied Mathematics and Mechanics(English Edition) 2019年第12期40卷 1759-1776页

作者： Lincong CHEN Haisheng zhu J.q.SUN College of Civil Engineering Huaqiao UniversityXiamen 361021Fujian ProvinceChina School of Engineering University of CaliforniaMercedCA 95343U.S.A

The vibroimpact systems with bilateral barriers are often encountered in ***,the dynamics of the vibroimpact system with bilateral barriers is full of *** closed-form solutions were *** this paper,we propose a novel method for random vibration analysis of single-degree-of-freedom(SDOF)vibroim-pact systems with bilateral barriers under Gaussian white noise excitations.A periodic approximate transformation is employed to convert the equations of the motion to a con-tinuous *** probabilistic description of the system is subsequently defined through the corresponding Fokker-Planck-Kolmogorov(FPK)*** closed-form station-ary probability density function(PDF)of the response is obtained by solving the reduced FPK equation and using the proposed iterative method of weighted residue together with the concepts of the circulatory probability flow and the potential probability ***,the versatility of the proposed approach is demonstrated by its application to two typical *** that the solution obtained by using the proposed method can be used as the benchmark to examine the accuracy of approximate solutions obtained by other methods.

关键词： bilateral barrier vibroimpact system weighted residue method iterative random vibration

Comparing Ordinary Kriging and Regression Kriging for Soil Properties in Contrasting Landscapes

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Pedosphere 2010年第5期20卷 594-606页

作者： q.zhu H.S.LIN Department of Crop and Soil Sciences 116 ASI BuildingThe Pennsylvania State UniversityUniversity ParkPA 16802(USA)

The accuracy between ordinary kriging and regression kriging was compared based on the combined consideration of sample size,spatial structure,and auxiliary variables(terrain indices and electromagnetic induction surveys) for a variety of soil properties in two contrasting landscapes(agricultural ***).when spatial structure could not be well captured by point-based observations(e.g.,when the ratio of sample spacing over correlation range was > 0.5),or when a strong relationship existed between target soil properties and auxiliary variables(e.g.,their R2 was > 0.6),regression kriging(RK) was more accurate for interpolating soil properties in both landscapes ***,ordinary kriging(OK) was *** depth and wetness condition did not appear to affect the selection of kriging for soil moisture interpolation,because they did not significantly change the ratio of sample spacing over correlation range and the relationship with the auxiliary *** of a smaller ratio of elevation change over total study area(E/A = 1.2) and multiple parent materials in the agricultural land,OK was generally more accurate in that *** contrast,a larger E/A ratio of 6.8 and a single parent material led to RK being preferable in the steep-sloped forested *** results from this study can be useful for selecting kriging for various soil properties and landscapes.

关键词： geostatistics soil moisture spatial interpolation spatial structure

The phylogenetic relationships of introduced Aphelinus （Hymenoptera： Aphelinidae）, biological control agents of the Russian wheat aphid （Homoptera： Aphididae）

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Insect Science 2009年第3期16卷 277-285页

作者： Yu Cheng zhu quentin q. Fang USDA-ARS-JwDSRC Stoneville MS 38776 Department of Biology Georgia Southern University Statesboro GA 30460 USA

Several species of Aphelinus have been introduced to the US from the Old world for biological control of the Russian wheat aphid, Diuraphis noxia （Modvilko）. Reproductive incompatibility has been observed among populations collected from different geographic areas. we examined whether or not the reproductive incompatibility between strains of A. asychis was caused by distant phylogenetic relationships. Ribosomal DNA sequences of internal transcribed spacers 2 （ITS2） were analyzed in several species of Aphelinus collected from multiple sites of Europe and Asia. Yhe phylogenetic analysis showed that strains within the species A. albipodus and A. asychis are not monophyletic, and two clearly divergent clades were revealed among sequenced samples. Our results suggest that the reproductive incompatibility between three exotic strains ofA. asychis was more likely caused by divergence of phylogeny than by symbiotic bacteria.

关键词： Aphelinus Aphidius ITS molecular systematics phylogeny rDNA

NUMERICAL SIMULATION OF EXTRUSION OF COMPOSITE POwDERS PREPARED BY HIGH ENERGY MILLING

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Acta Metallurgica Sinica(English Letters) 2004年第1期17卷 51-54页

作者： X.q.Li w.P.Chen w.Xia q.L.zhu Y.Y.Li E.D.wang College of Mechanical Engineering South China University of Technology.Guangzhou 510640 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Based on the characteristic of high energy milling and the micromechanics of composite material, a plastic constitutive equation is implemented for milled composite powders. To check the equation, the extrusion of Ti/Al composite powders prepared by high energy milling was simulated. It was from the numerical analysis that the predicted extrusion pressure mounted up with milling time and extrusion ratio increasing, which was perfect agreement with experimental results.

关键词： high energy milling composite powder plastic constitutive equation extrusion numerical simulation