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Hot deformation behavior of EA4T steel

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Acta Metallurgica Sinica(English Letters) 2012年第5期25卷 374-382页

作者： Gang XU lina WANG Shiqi LI Le WANG School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing 100083 China School of Materials Science and Engineering University of Science and Technology Beijing Beijing100083 China

The compressive deformation behavior of EA4T steel was investigated at tempera- tures ranging from 950 to 1150℃ and strain rates from 0.1 to 20 s-1 on Gleeble-1500 thermo-simulation machine. The work hardening rate versus stress curves were used to determine the characteristic points of flow curves. The application of constitutive equations to determine the hot working constants of this material was discussed. Fur- thermore, the effect of Zener-Hollomon parameter （Z） on the characteristic points of flow curves was studied using the power law relation. The deformation activation energy of this steel was determined as 309.5 kJ/mol. Some behaviors were compared to other steels.

关键词： EA4T steel Constitutive equations Activation energy Workhardening rate

Orientation factor analysis of deformation mechanisms under special processing techniques in AZ31 magnesium alloys

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Acta Metallurgica Sinica(English Letters) 2010年第1期23卷 63-71页

作者： Ping YANG lina WANG Xiao LI Li MENU School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Material Department School of Tianjin University of Science and Technology Beijing Tianjin 301830 China

Experiments show that special processing techniques such as asymmetrical rolling （ASR）, equal channel angular pressing （ECAP） and equal channel angular rolling （ECAR） can weaken the basal texture of the magnesium alloys and therefore improve their plasticity. However, the deformation mechanisms related are different. In this paper, we determine the deformation mechanisms activated during ASR, ECAP and ECAR by calculation of orientation factors. Analysis shows that during ASR the shear stress σ13 on the rolling plane of the samples obviously weakens the basal slip and tension twinning that all produce basal texture and improve plasticity due to the promotion of tilt basal texture. During ECAP the shear stress σs on the intersecting plane of two channels promotes tension twinning in the basal oriented grains, whereas under ECAR the shear stress σ13 induced by roller friction on the rolling plane produces the shear stress as on the intersection plane of the two channels that also promotes tension twinning. Although the shear strain is lower in ECAR than in ECAP, the channel clearance in ECAR facilitates tension twinning.

关键词： Magnesium Asymmetrical rolling Equal channel angular pressing Equal channel angular rolling Deformation

Research on Eddy Current Testing System of the Carburized Layer Depth of 20CrMnTi Steel

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材料热处理学报 2004年第5期25卷 409-411页

作者： CHENGXiao-min lina WUXin-wen FANGHua-bin SchoolofMaterialsScienceandEngineering WuhanUniversityofTechnologyWuhanChina SchoolofMaterialsScienceandEngineering ShanghaiJiaoTongUniversityShanghaiChina

In this paper the carbon distribution in the carburized layer of 20CrMnTi steel was studied. The relationship between the depth of a carburized layer and the surface carbon distribution was established. Eddy current testing system of the case depth of this carburized steel was built by using ANSYS software as second development platform.

关键词： 20CrMnTi钢渗碳渗碳层厚度涡流试验有限元

Achievement of chaotic synchronization trajectories of master-slave manipulators with feedback control strategy

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Acta Mechanica Sinica 2010年第3期26卷 433-439页

作者： Qingkai Han lina Hao Hao Zhang Bangchun Wen School of Mechanical Engineering and Automation Northeastern University 110004 Shenyang China

This paper addresses a master-slave synchro- nization strategy for complex dynamic systems based on feedback control. This strategy is applied to 3-DOF pla- nar manipulators in order to obtain synchronization in such complicated as chaotic motions of end-effectors. A chaotic curve is selected from Duffing equation as the trajectory of master end-effector and a piecewise approximation method is proposed to accurately represent this chaotic trajectory of end-effectors. The dynamical equations of master-slave manipulators with synchronization controller are derived, and the Lyapunov stability theory is used to determine the stability of this controlled synchronization system. In numer- ical experiments, the synchronous motions of end-effectors as well as three joint angles and torques of master-slave manipulators are studied under the control of the proposed synchronization strategy. It is found that the positive gain matrix affects the implementation of synchronization con- trol strategy. This synchronization control strategy proves the synchronization＇s feasibility and controllability for com- plicated motions generated by master-slave manipulators.

关键词： Master-slave manipulators - Chaoticsynchronization trajectory - Feedback control

Design of a fault diagnosis scheme for a class of singular nonlinear systems

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控制理论与应用（英文版） 2008年第2期6卷 122-126页

作者： lina YAO Hong WANG School of Electrical Engineering Zhengzhou University Zhengzhou Henan 450001 China Control Systems Centre University of Manchester Manchester M60 1QD United Kingdom Institute of Automation Chinese Academy of Sciences Beijing 100080 China Institute of Automation Northeastern University Shenyang Liaoning 110006 China

A new fault detection and diagnosis approach is developed in this paper for a class of singular nonlinear systems via the use of adaptive updating rules. Both detection and diagnostic observers are established, where Lyapunov stability theory is used to obtain the required adaptive tuning rules for the estimation of the process faults. This has led to stable observation error systems for both fault detection and diagnosis. A simulated numerical example is included to demonstrate the use of the proposed approach and encouraging results have been obtained.

关键词： Fault detection Fault diagnosis Singular Nonlinear systems Adaptive update rules

FURTHER RESEARCH OF A NEW KIND OF SERIES REPAIRABLE SYSTEM

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Journal of Systems Science & Complexity 2012年第4期25卷 744-758页

作者： lina GUO Houbao XU Chao GAO Guangtian ZHU Department of Mathematics Taiyuan University of Technology Department of Mathematics Beijing Institute of Technology Department of System Engineering Beijing Institute of Information and Control Academy of Mathematics and System Sciences Chinese Academy of Sciences

This paper is devoted to studying the uniqueness and existence of the system dynamic solution by using C0-semigroup theory and discussing its exponential stability by analyzing the spectrul distribution of system operator and its quasi-compactness. Some primary reliability indices are discussed with the eigenfunction of system operator and the optimal vacation time to get the maximum system profit is analyzed at the end of paper.

关键词： Co-semigroup theory dynamic solution exponential stability profit analysis reliability indices steady-state solution.

SEM in-situ investigation on fatigue cracking behavior of P/M Rene95 alloy with surface inclusions

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Journal of University of Science and Technology Beijing 2006年第3期13卷 244-249页

作者： Xishu Wang lina Zhang Yanping Zeng Xishan Xie School of Aerospace Tsinghua University Beijing 100084 China Department of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Department of Material Science and Engineering Tsinghua University Beijing 100084 China

The low-cycle fatigue behavior of powder metallurgy Rene95 alloy containing surface inclusions was investigated by in-situ observation with scanning electron microscopy （SEM）. The process of fatigue crack initiation and early stage of propagation behavior indicates that fatigue crack mainly occurs at the interface between the inclusion and the matrix. The effect of inclusion on the fatigue crack initiation and the early stage of crack growth was very obvious. The fatigue crack growth path in the matrix is similar to the shape of inclusion made on the basis of fatigue fracture image analysis. The empiric relation between the surface and inside crack growth length, near a surface inclusion, can be expressed. Therefore, the fatigue crack growth rate or life of P/M Rene95 alloy including the inclusions can be evaluated on the basis of the measurable surface crack length parameter. In addition, the effect of two inclusions on the fatigue crack initiation behavior was investigated by the in-situ observation with SEM.

关键词： P/M Rene95 alloy fatigue behavior inclusion powder metallurgy in-situ observation SEM

Process optimization study on the carbonylation of methyl acetate

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Chinese Journal of Chemical Engineering 2018年第9期26卷 1937-1942页

作者： Baohe Wang Baomin Ge Jing Zhu lina Wang Key Laboratory for Green Chemical Technology of Ministry of Education Research and Development Center of Petrochemical Technology Tianjin University

Acetic anhydride is the important organic chemical raw material, and is used widely in chemical industry,pharmaceutical industry, dyes, spices and other fields. In this paper, the process of carbonylation of methyl acetate in rhodium iodine catalyst system was studied, and the suitable reaction conditions were *** the same time, the kinetic model was established. The optimum reaction conditions were as follows： the reaction pressure was 5 MPa, the hydrogen content was 8%, the amount of iodomethane was 15%, the amount of lithium iodide was 3%, the reaction temperature was 150 ℃ and the reaction time is 3 h. Under the above reaction conditions, the selectivity of the reaction is close to 100% and the conversion is as high as 92%. The macroscopic kinetic model of the reaction was established in the temperature range of 120 ℃–150 ℃. The reaction is an irreversible reaction without the formation of by-products and the dynamic equation is also given in the Conclusions section.

关键词： Carbonylation Rhodium iodine catalyst Reaction conditions Kinetics

Loading calcium fluorescent probes into protoplasts to detect calcium in the flesh tissue cells of Malus domestica

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Horticulture Research 2020年第1期7卷 1561-1571页

作者： lina Qiu Yongzhang Wang Haiyong Qu College of Horticulture Qingdao Agricultural UniversityQingdao CityChina

Cytosolic Ca^(2+)plays a key role in signal transduction in *** imaging is the most common approach to studying dynamic changes in the cytoplasmic Ca^(2+)***,we used mature‘Fuji’apples(Malus pumila Mill.)to obtain viable protoplasts from flesh tissue cells by enzymatic hydrolysis;then,three small-molecule fluorescent probes(fluo-8/AM,fluo-4/AM,and rhod-2/AM)were loaded into the *** three Ca^(2+)fluorescent probes successfully entered the cytoplasm but did not enter the *** the Ca^(2+)chelator(EGTA)and Ca^(2+)channel blocker(La3+)reduced the fluorescence intensity in the *** calcium ionophore A23187 increased the fluorescence intensity in the cytoplasm at 5μmol/L but decreased it at 50μmol/***,A23187 reversed the fluorescence intensity in the cytoplasm,which was decreased by La3+.Ionomycin is also a calcium ionophore that can increase the fluorescence intensity of calcium in the *** results suggest that small-molecule Ca^(2+)fluorescent probes can be used to detect changes in cytosolic calcium levels in the cells of fruit flesh *** addition,the optimum concentration of fluo-8/AM was determined to be 5μmol/*** was the first time that protoplasts have been isolated from apple flesh tissue cells and small-molecule fluorescent probes have been used to detect calcium in the cytoplasm of flesh tissue *** study provides a new method to study calcium signal transduction in fruit flesh tissue.

关键词： reversed probes hydrolysis