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Fabrication of a Novel Hybrid Scaffold for Tissue Engineered Heart Valve

Journal of Huazhong university of Science and Technology(Medical Sciences) 2009年第5期29卷 599-603页

作者：洪昊董念国史嘉玮陈思郭超胡平齐宏旭 department of Cardiovascular Surgery Union HospitalTongji Medical CollegeHuazhong University of Science and Technology department of Chemical engineering Institute of Polymer Science and TechnologyTsinghua University

The aim of this study was to fabricate biomatrix/polymer hybrid scaffolds using an electrospinning technique. Then tissue engineered heart valves were engineered by seeding mesenchymal stromal cells （MSCs） onto the scaffolds. The effects of the hybrid scaffolds on the proliferation of seed cells, formation of extracellular matrix and mechanical properties of tissue engineered heart valves were investigated. MSCs were obtained from rats. Porcine aortic heart valves were decellularized, coated with poly（3-hydroxybutyrate-co-4-hydroxybutyrate） using an electrospinning technique, and reseeded and cultured over a time period of 14 days. In control group, the decellularized valve scaffolds were reseeded and cultured over an equivalent time period. Specimens of each group were examined histologically （hematoxylin-eosin [HE] staining, immunohistostaining, and scanning electron microscopy）, biochemically （DNA and 4-hydroxyproline） and mechanically. The results showed that recellularization was comparable to the specimens of hybrid scaffolds and controls. The specimens of hybrid scaffolds and controls revealed comparable amounts of cell mass and 4-hydroxyproline （P〉0.05）. However, the specimens of hybrid scaffolds showed a significant increase in mechanical strength, compared to the controls （P〈0.05）. This study demonstrated the superiority of the hybrid scaffolds to increase the mechanical strength of tissue engineered heart valves. And compared to the decellularized valve scaffolds, the hybrid scaffolds showed similar effects on the proliferation of MSCs and formation of extracellular matrix. It was believed that the hybrid scaffolds could be used for the construction of tissue engineered heart valves.

关键词： tissue engineered heart valve hybrid scaffold electrospinning mesenchymal stem cells

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Nonlinear Adaptive Governor Control of Synchronous Generator

Nonlinear Adaptive Governor Control of Synchronous Generator

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第二十四届中国控制会议

作者： Jiao Xiaohong~(1,3), Sun Yuanzhang~1 , Shen Tielong(1.department of electrical engineering, Tsinghua university, beijing, 10084, china 2.department of mechanical engineering, Sopliia university, Tokyo. 102-8554, Japan 3. department of electrical engineering, Yanshan university, Qinhuangdao, 066004, china)

＜正＞ The transient stabilization problem with voltage regulation is investigated in this paper for the synchronous generator with the governor control based on the modem nonlinear adaptive techniques. A nonlinear adaptive feedback control is designed that drives the system to the new equilibrium generated by permanent fault in transmission line and regulates the generator terminal voltage to the required value. Some simulation results are given to demonstrate the effectiveness of the proposed control schemes.

关键词： Nonlinear adaptive control governor control synchronous generator transient stability voltage regulation

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An improved group search optimizer for mechanical design optimization problems

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Progress in Natural Science:Materials International 2009年第1期19卷 91-97页

作者： Hai Shena,b,c,Yunlong Zhu a,Ben Niu a,b,Q.H.Wu d a Key Laboratory of Industrial Informatics,Shenyang Institute of Automation,Chinese Academy of Sciences,Shenyang 110016,china b Graduate School of the Chinese Academy of Sciences,beijing 100049,china c College of Physics Science and Technology,Shenyang Normal university,Shenyang 110034,china d department of electrical engineering and Electronics,The university of Liverpool,Brownlow Hill,Liverpool,L69 3GJ,UK Key Laboratory of Industrial Informatics Shenyang Institute of Automation Chinese Academy of Sciences Shenyang 110016 China Graduate School of the Chinese Academy of Sciences Beijing 100049 China College of Physics Science and Technology Shenyang Normal University Shenyang 110034 China department of electrical engineering and Electronics The University of Liverpool Brownlow Hill Liverpool L69 3GJ UK

This paper presents an improved group search optimizer(iGSO) for solving mechanical design optimization *** the proposed algorithm,subpopulations and a co-operation evolutionary strategy were adopted to improve the global search capability and convergence *** iGSO is evaluated on two optimization problems of classical mechanical design:spring and pressure *** experimental results are analyzed in comparison with those reported in the *** results show that iGSO has much better convergence performance and is easier to implement in comparison with other existing evolutionary algorithms.

关键词： mechanical optimization problem GSO Constrained optimization problem

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水轮发电机组主轴系统的建模及其非线性瞬态响应

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清华大学学报（自然科学版） 1998年第6期38卷 123-128页

作者：李苹窦海波王正清华大学工程力学系

讨论了大型水轮发电机组主轴系统的建模问题，建立了一个具有局部非线性的多自由度轴系模型。各个导轴承的油膜作为非线性元件，并考虑回转效应、摆动惯性、剪切效应、发电机的电磁拉力、水的附加惯性等因素以及作用在轴上任意形式的机... 详细信息

讨论了大型水轮发电机组主轴系统的建模问题，建立了一个具有局部非线性的多自由度轴系模型。各个导轴承的油膜作为非线性元件，并考虑回转效应、摆动惯性、剪切效应、发电机的电磁拉力、水的附加惯性等因素以及作用在轴上任意形式的机械、电磁和水动的激励力。瞬态响应的计算综合采用了Ｒｉｃｃａｔｉ传递矩阵法和Ｎｅｗｍａｒｋ－β数值积分法。推导了求解瞬态响应的公式，编制了通用的计算软件。以湖南凌源五强溪电厂的２４０ＭＷ大型水轮发电机组轴系为实例，给出了计算结果和讨论，为大型水轮发电机组的稳定性研究提供参考和技术支持。

关键词：水轮发电机组转子轴承系统非线性瞬态响应

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Electromechanical liquid crystal theory of vesicles

Electromechanical liquid crystal theory of vesicles

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第九届全国生物力学学术会议

作者： Xi-Qiao Feng(department of engineering Mechanics,Tsinghua university,beijing 100084,china)

An electromechanical liquid crystal theory will be presented for modeling the morphology evolution of a lipid vesicle under mechanical and electrical ***,a general equation that governs the vesicle shape is established by considering the effects of elastic bending,osmotic pressure,surface tension,Maxwell pressure,as well as the flexoelectric and dielectric properties of the *** the special case of an axisymmetric vesicle,the shape equations are analyti-

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An Electro-mechanical Coupled Mesh-Free Method for Fracture Analysis of Cracks in Piezoelectric Ceramic Materials

An Electro-Mechanical Coupled Mesh-Free Method for Fracture ...

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The Sixth World Congress on Computational Mechanics in Conjunction with the Second Asian-Pacific Congress on Computational Mechanics

作者： Xianghua Guo, Daining Fang department of engineering Mechanics, Tsinghua university, beijing, 100084, china

Based on the moving least square interpolation, an electro-mechanical coupled element free Galerkin method is developed to analyze crack propagation in piezoelectric ceramic structures subjected to electro-mechanical coupled loading. The EFG method establishes discrete equations in term of the Gauss integration based on background, so it is accurate and stable. In this paper, the displacement and electric potential are employed as nodal variables and the general displacement boundary conditions are introduced into discrete equations by the penalty function method, so that the stiff matrix is sparse, symmetrical and positive definite, which can considerably reduce computational effort. In order to satisfy the discontinuity of both mechanical and electric displacements in nonconvex bodies, such as cracks and holes, the discontinuous diffraction functions [1] are introduced into weight functions. An infinite plate with a central circular defect is studied to verify the validity of our electro-mechanical coupled method. The agreement between the predicted stress and electric field distribution with those obtained from existing numerical simulation [2] and exact theoretical solutions [3]. In order to investigate both stress and electric field distributions at a crack tip in a piezoelectric material, a single edge-notched specimen has been modeled. In the discrete equations, some basis functions with singular items are adopted to catch the singularity of stress and electric field. In addition, the nodal refinement is carried out around the crack tip. The numerical results show that both the ratio of the electrical to the mechanical loads and the direction of electric field have important effects on the angle at which the hoop stress reaches its maximum value, which makes the crack has the tendency to propagate straightward or deviate away from the crack line. In some practical performances, the piezoelectric materials are often deposited on the substrates. Some cracks wil

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Condition Monitoring Method of the Equipment Based on Extension Neural Network

Condition Monitoring Method of the Equipment Based on Extens...

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2010 Chinese Control and Decision Conference

作者： Juncai Zhang~1,Xu Qian~1,Yu Zhou~(1,2),Ai Deng~3 1.School of mechanical Electronic and Information engineering,china university of Mining and Technology(beijing), beijing,100083,china 2.department of electrical & Computer engineering,university of Alberta,Edmonton,T6G 2V4,Canada 3.School of Software engineering,Tongji university,Shanghai,201804,china

In this paper,a novel condition monitoring method of equipment based on extension neural network(ENN) is ***,this paper introduces the central ideas of extension *** it presents the extension theory neural, including its structure and learning *** the end of the paper,the reduction gearbox of a certain equipment is researched and the extension neural network is employed to design a condition monitoring method that can detect the current condition of reduction *** experiment results indicate that the proposed method can determine the condition of machine rapidly and accurately with less time and computation.

关键词： Extension theory Extension neural network Condition monitoring Reduction gearbox

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ANALYSIS OF CONDITIONS MONITOR AND FAULT SYNTHETICAL DIAGNOSIS OF mechanical AND electrical EQUIPMENT IN MINE

ANALYSIS OF CONDITIONS MONITOR AND FAULT SYNTHETICAL DIAGNOS...

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第四届世界维修大会

作者： SU Shun department of electrical and mechanical Management Datong Coal Mine Group Company Datong Shan’xi 037003 china.ZHANG Yue-chao beijing university of Technology Pingleyuan NO.100 beijing 100124 china

For the special working condition of equipment under coal mine, taken common fault appeared in major mechanical and electrical equipment of Datong Coal Mine Group as example, effective methods of conditions monitoring, fault diagnosis and examining and repairing are summarized. It achieved the goal of predicting fault in advance, maintaining conditions and improving the efficiency of equipment. The actual application result shows that the technology can achieve reliable and efficient working of equipment;it also provides protection for high-yielding and efficient produce.

关键词： mechanical and electrical equipment of coal mine, fault diagnoses condition monitoring, equipment maintenance.

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High Performance Motor-Pressing Control System of Hot Plate Leveler Based on Model Predictive Control

High Performance Motor-Pressing Control System of Hot Plate ...

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2011 Chinese Control and Decision Conference（CCDC）

作者： Dong Liu,Ms.,is with the electrical engineering department,MCC Capital engineering & Research Incorporation Limited.,beijing,china.Yunbo Wang,SE.,is with the electrical engineering department,MCC Capital engineering & Research Incorporation Limited.,beijing,china.

This paper introduced the configuration of Hot Plate Level system,and built the mathematic model of pressing device which is driven by two asynchronous *** we known from the model,the pressing system was a classic low gain,non-linear and high-coupling *** the speed gain of asynchronous motor system,expanding the band width of close-loop speed system and increasing speed response of pressing system were the core methods of reducing the disturbance of speed close-loop *** keys of controlling close-loop position system were eliminating the non-linearity of speed-loop and hysteretic position-circle which is caused by the backlash of worm wheel and *** structure of the pressing system based on two motors,by which the rudimental plastic deformation can be removed,produced the high-coupling characteristic,which reduced the position precision and dynamic *** simplifying pressing system according to the system mechanical structure and using the controller based on Predictive Control Theory,the four pressing position of the pressing system is adjusted and balanced,and the linearity and decoupling were *** complex controlling system for motor-pressing hot plate leveler was successfully used in Tang Shan Heavy Plate Mill Line 2,which increased the production capability of the rolling *** study and solution is made to overcome the choke point of the precise positioning in most Plate Level *** is proved via matlab simulations that high performance and strong robusticity can be achieved.

关键词： Predictive Control System Motor Press System Hot Plate Leveler

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A Gain-Scheduled State Feedback Control Method for the Transcient Stability Control of A Single-Machine Infinite-Bus Power System

A Gain-Scheduled State Feedback Control Method for the Trans...

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第25届中国控制会议

作者： He Rong,Liu Kangzhi,Mei Shengwei,Gui Xiaoyang department of Electronics and mechanical engineering,Chiba university 1-33 Yayoi-cho,Inage-ku,Chiba 263-8522,Japan department of electrical engineering,Tsinghua university beijing, china

In this paper,a new approach is proposed for the transient stability control of a single-machine infinite-bus power system. The proposed method is based on the concept of linear parameter varying (LPV) model and linear matrix inequality(LMI) based gain-scheduling control. It is well-known that when the disturbances are large, the nonlinearity inherent in the power system can no longer be ignored and the performance of closed-loop system designed based on linear approximation degrades severely in such case. Here, we propose a control method which handles the nonlinear model directly and is able to assign the convergence rate. First,we show that the nonlinear model can be transformed into an LPV system with the rotor angle as the time-varying parameter. Then, a gain-scheduled controller is designed by using the gain-scheduling control method. In particular,the input saturation is taken into consideration in the design. Simulation results verify that the proposed method is effective.

关键词： Gain scheduling linear parameter varying (LPV) linear matrix inequalities (LMIs) polytopic form singlemachine infinite-bus power system

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