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Investigation on the choice of boundary conditions and shape functions for flexible multi-body system

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Acta Mechanica Sinica 2012年第1期28卷 180-189页

作者： Ke-qi pan Jin-Yang Liu School of Naval Architecture Ocean and Civil EngineeringShanghai Jiaotong University200240 ShanghaiChina

The objective of this investigation is to examine the correctness and efficiency of the choice of boundary conditions when using assumed mode approach to simulate flexible multi-body systems. The displacement field due to deformation is approximated by the Rayleigh-Ritz assumed modes in floating frame of reference （FFR） formulation. The deformations obtained by the absolute nodal coordinate （ANC） formulation which are transformed by two sets of reference coordinates are introduced as a criterion to verify the accuracy of the simulation results by using the FFR formulation. The relationship between the deformations obtained from different boundary conditions is revealed. Nu- merical simulation examples demonstrate that the assumed modes with cantilevered-free, simply-supported and free- free boundary conditions without inclusion of rigid body modes are suitable for simulation of flexible multi-body system with large over all motion, and the same physical deformation can be obtained using those mode functions, differ only by a coordinate transformation. It is also shown that when using mode shapes with statically indeterminate boundary conditions, significant error may occur. Furthermore, the slider crank mechanism with rigid crank is accurate enough for investigating boundary condition problem of flexible multi-body system, which cost significant less simulating time.

关键词： Multi-body systems. Boundary conditions - Assumed mode approach

A Variant of the Dual Face Algorithm Using Gauss-Jordan Elimination for Linear Programming

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Journal of the Operations Research Society of China 2016年第3期4卷 347-356页

作者： Ping-qi pan Department of Mathematics Southeast UniversityNanjing 210096China

Using Cholesky factorization, the dual face algorithm was described forsolving standard Linear programming (LP) problems, as it would not be very suitablefor sparse computations. To dodge this drawback, this paper pre... 详细信息

关键词： Linear programming Bounded-variable Dual face Dual optimal face Gauss-Jordan elimination

Geometric nonlinear dynamic analysis of curved beams using curved beam element

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Acta Mechanica Sinica 2011年第6期27卷 1023-1033页

作者： Ke-qi pan Jin-Yang Liu School of Naval Architecture Ocean and Civil Engineering Shanghai Jiaotong University 200240 Shanghai China

Instead of using the previous straight beam element to approximate the curved beam,in this paper,a curvilinear coordinate is employed to describe the deformations,and a new curved beam element is proposed to model the curved *** on exact nonlinear strain-displacement relation,virtual work principle is used to derive dynamic equations for a rotating curved beam,with the effects of axial extensibility,shear deformation and rotary inertia taken into *** constant matrices are solved numerically utilizing the Gauss quadrature integration *** and Newton-Raphson iteration methods are adopted to solve the differential equations of the rigid-flexible coupling *** present results are compared with those obtained by commercial programs to validate the present finite *** order to further illustrate the convergence and efficiency characteristics of the present modeling and computation formulation,comparison of the results of the present formulation with those of the ADAMS software are ***,the present results obtained from linear formulation are compared with those from nonlinear formulation,and the special dynamic characteristics of the curved beam are concluded by comparison with those of the straight beam.

关键词： Curved beam element. Geometric nonlinear formulation Rigid-flexible coupling

A GENERALIZED QUASI-NEWTON EQUATION AND COMPUTATIONAL EXPERIENCE

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Journal of Computational Mathematics 2006年第5期24卷 665-674页

作者： Lei-hong Zhang Ping-qi pan Department of Mathematics Southeast University Nanjing 210096 China

The quasi-Newton equation has played a central role in the quasi-Newton methods for solving systems of nonlinear equations and/or unconstrained optimization problems. Insteady pan suggested a new equation, and showed that it is of the second order while the traditional of the first order, in certain approximation sense [12]. In this paper, we make a generalization of the two equations to include them as special cases. The generalized equation is analyzed, and new updates are derived from it. A DFP-like new update outperformed the traditional DFP update in computational experiments on a set of standard test problems.

关键词： System of nonlinear equations, Unconstrained optimization, Quasi-Newtone quation Second-order Quasi-Newton equation, Update formula.

Predicting coastal morphological changes with empirical orthogonal function method

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Water Science and Engineering 2016年第1期9卷 14-20页

作者： fernando alvarez shun-qi pan Hydro-environmental Research Centre School of Engineering Cardiff University Cardiff CF24 3AA UK

In order to improve the accuracy of prediction when using the empirical orthogonal function （EOF） method, this paper describes a novel approach for two-dimensional （2D） EOF analysis based on extrapolating both the spatial and temporal EOF components for long-term prediction of coastal morphological changes. The approach was investigated with data obtained from a process-based numerical model, COAST2D, which was applied to an idealized study site with a group of shore-parallel breakwaters. The progressive behavior of the spatial and temporal EOF components, related to bathymetric changes over a training period, was demonstrated, and EOF components were extrapolated with combined linear and exponential functions for long-term prediction. The extrapolated EOF components were then used to reconstruct bathymetric changes. The comparison of the reconstructed bathymetric changes with the modeled results from the COAST2D model illustrates that the presented approach can be effective for long-term prediction of coastal morphological changes, and extrapolating both the spatial and temporal EOF components yields better results than extrapolating only the temporal EOF component.

关键词： EOF method Coastal morphological change Long-term prediction Process-based numerical model Shore-parallel breakwater

Late-Time Evolution of the Phantom Scalar Perturbation in the Background of a Spherically Symmetric Static Black Hole

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Chinese Physics Letters 2010年第6期27卷 9-12页

作者： pan qi-Yuan JING Ji-Liang Institute of Physics and Department of Physics Hunan Normal University Changsha 410081

The late-time evolution of the phantom scalar perturbation is investigated in the spacetime of a four-dimensionai spherically symmetric static black hole. It is revealed that the asymptotic tail of the phantom scalar field is dominated by the growth behavior t-（l＋3/2）eμt, which depends on the multipole moment l and the field moss but is independent of the mass M and charge Q of the black hole. This growth behavior is in strong contrast to the decaying tall of the usual massive scalar perturbation and shows that the external phantom scalar perturbation is unstable in the spherically symmetric static black hole spacetime.

关键词： Limonium sinuatum Growth Tail Fields

Enhanced ferromagnetism and magnetoelectric response in quenched BiFeO3-based ceramics

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Chinese Physics B 2020年第8期29卷 465-470页

作者： qi pan Bao-Jin Chu Key Laboratory of Materials for Energy Conversion Chinese Academy of Sciences(CAS)Department of Materials Science and EngineeringUniversity of Science and Technology of ChinaHefei 230026China

The piezoelectric,ferromagnetism,and magnetoelectric response of BiFeO3-BaTiO3 ceramics with the compositions around the morphotropic phase boundary(MPB)of the solid solution are systematically investigated after the ceramics have been quenched from a high *** find that the ferromagnetism of the quenched ceramics is greatly *** enhanced piezoelectric response d33 larger than 200 pC/N,which could be sustained up to 350℃,is *** a result of enhanced ferromagnetism and piezoelectric response,a large magnetoelectric response^1.3 V/cm·Oe(1 Oe=79.5775 A·m^-1)is obtained near the mechanical resonance frequency of the quenched ceramic *** research also shows that in addition to the ferromagnetism and piezoelectric response,the mechanical quality factor is another important parameter to achieve high magnetoelectric response because the physical effects are coupled through mechanical interaction in BiFeO3-based *** work suggests that quenching is an effective approach to enhancing the magnetoelectric response of BiFeO3-based materials and the materials belong to single-phase multiferroic materials with high magnetoelectric response.

关键词： multiferroic materials magnetoelectric ferromagnetic piezoelectric

Programmable soft bending actuators with auxetic metamaterials

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Science China(Technological Sciences) 2020年第12期63卷 2518-2526页

作者： pan qi CHEN ShiTong CHEN FeiFei ZHU XiangYang Robotics Institute School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China State Key Laboratory of Mechanical System and Vibration Shanghai Jiao Tong UniversityShanghai 200240China

Soft robotics has been receiving increasing attention due to its flexibility and adaptability offered by embodied intelligence. A soft robot may undergo complex motions including stretching,contraction,bending,twisting,and their intricate *** these basic motions,bending plays a central role when a robot accomplishes tasks such as locomotion,grasping and manipulation. Although a rich repertoire of bending mechanisms has been reported,a systematic and rational design framework is still lack. In this paper,we provide a novel design strategy for soft bending actuators which allows integral modeling and design optimization. Nowadays,metamaterials are emerging as a new tool for soft robots,by encoding the desired complex motions directly within the material architectures,leading to conformable monolithic systems. We combine pneumatic actuators and flexible metamaterials to provide an alternative solution to soft bending actuators,with advantages of compact design,large bending motion,and convenient fabrication. A regular pneumatic chamber is embedded inside auxetic and non-auxetic metamaterials,and bending is generated when inflated. We carry out dimensionless analysis to identify the key design variables. To provide insight into design optimization,we develop a computation framework by modeling metamaterial structures with beam elements and the inner chamber with shell elements as an integral part,allowing efficient simulation of the coupled system. We systematically investigate how the bending angle varies with the key design variables and find the optimal design *** experimental results are well in line with the simulation,and a remarkable bending motion of 0.43°/mm is achieved.

关键词： soft robotics bending actuator auxetic metamterials negative Poisson’s ratio

Aldolase B attenuates clear cell renal cell carcinoma progression by inhibiting CtBP2

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Frontiers of Medicine 2023年第3期17卷 503-517页

作者： Mingyue Tan qi pan qi Wu Jianfa Li Jun Wang Department of Urology Shanghai General HospitalShanghai Jiao Tong University School of MedicineShanghai 200080China Urology Center Shuguang HospitalShanghai University of Traditional Chinese MedicineShanghai 201203China Department of Urology The Sixth Affiliated Hospital of Wenzhou Medical University(The People’s Hospital of Lishui)Lishui 323000China

Aldolase B(ALDOB),a glycolytic enzyme,is uniformly depleted in clear cell renal cell carcinoma(ccRCC)*** previously showed that ALDOB inhibited proliferation through a mechanism independent of its enzymatic activity in ccRCC,but the mechanism was not unequivocally *** showed that the corepressor C-terminal-binding protein 2(CtBP2)is a novel ALDOB-interacting protein in *** CtBP2-to-ALDOB expression ratio in clinical samples was correlated with the expression of CtBP2 target genes and was associated with shorter *** inhibited CtBP2-mediated repression of multiple cell cycle inhibitor,proapoptotic,and epithelial marker ***,ALDOB overexpression decreased the proliferation and migration of ccRCC cells in an ALDOB-CtBP2 interaction-dependent ***,our findings showed that ALDOB recruited acireductone dioxygenase 1,which catalyzes the synthesis of an endogenous inhibitor of CtBP2,4-methylthio 2-oxobutyric *** functions as a scaffold to bring acireductone dioxygenase and CtBP2 in close proximity to potentiate acireductone dioxygenase-mediated inhibition of CtBP2,and this scaffolding effect was independent of ALDOB enzymatic ***,increased ALDOB expression inhibited tumor growth in a xenograft model and decreased lung metastasis in *** findings reveal that ALDOB is a negative regulator of CtBP2 and inhibits tumor growth and metastasis in ccRCC.

关键词： ALDOB kidney cancer cell proliferation