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Interstitial fluid flow:simulation of mechanical environment of cells in the interosseous membrane

Acta Mechanica Sinica 2011年第4期27卷 602-610页

作者： wei Yao guang-Hong Ding Department of Mechanics and Engineering Science Fudan University Shanghai Research Center of Acupuncture 200433 Shanghai China

In vitro experiments have shown that subtle fluid flow environment plays a significant role in living biological tissues, while there is no in vivo practical dynamical measurement of the interstitial fluid flow velocity. On the basis of a new finding that capillaries and collagen fibrils in the interosseous membrane form a parallel array, we set up a porous media model simulating the flow field with FLUENT software, studied the shear stress on interstitial cells＇ surface due to the interstitial fluid flow, and analyzed the effect of flow on protein space distribution around the ceils. The numerical simulation results show that the parallel nature of capillaries could lead to directional interstitial fluid flow in the direction of capillaries. Interstitial fluid flow would induce shear stress on the membrane of interstitial cells, up to 30 Pa or so, which reaches or exceeds the threshold values of cells＇ biological response observed in vitro. Interstitial fluid flow would induce nonuniform spacial distribution of secretion protein of mast cells. Shear tress on cells could be affected by capillary parameters such as the distance between the adjacent capillaries, blood pressure and the permeability coefficient of capillary＇s wall. The interstitial pressure and the interstitial porosity could also affect the shear stress on cells. In conclusion, numerical simulation provides an effective way for in vivo dynamic interstitial velocity research, helps to set up the vivid subtle interstitial flow environment of cells, and is beneficial to understanding the physiological functions of interstitial fluid flow.

关键词： Interstitial fluid flow Porous media. Numericalsimulation - Acupoint Sheer stress

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ACCELERATION METHODS OF NONLINEAR ITERATION FOR NONLINEAR PARABOLIC EQUATIONS

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Journal of Computational Mathematics 2006年第3期24卷 412-424页

作者： guang-wei Yuan Xu-deng Hang Laboratory of Computational Physics Institute of Applied Physics and Computational Mathematics P.O.Box 8009 Beijing 100088 China

This paper discusses the accelerating of nonlinear parabolic equations. Two iterative methods for solving the implicit scheme new nonlinear iterative methods named by the implicit-explicit quasi-Newton （IEQN） method and the derivative free implicit-explicit quasi-Newton （DFIEQN） method are introduced, in which the resulting linear equations from the linearization can preserve the parabolic characteristics of the original partial differential equations. It is proved that the iterative sequence of the iteration method can converge to the solution of the implicit scheme quadratically. Moreover, compared with the Jacobian Free Newton-Krylov （JFNK） method, the DFIEQN method has some advantages, e.g., its implementation is easy, and it gives a linear algebraic system with an explicit coefficient matrix, so that the linear （inner） iteration is not restricted to the Krylov method. Computational results by the IEQN, DFIEQN, JFNK and Picard iteration methods are presented in confirmation of the theory and comparison of the performance of these methods.

关键词： Nonlinear parabolic equations Difference scheme Newton iterative methods.

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Dual-steering mode based on direct yaw moment control for multi-wheel hub motor driven vehicles:Theoretical design and experimental assessment

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Defence Technology（防务技术） 2022年第1期18卷 49-61页

作者： Zheng Zhang Xiao-jun Ma Chun-guang Liu Shu-guang wei Department of Weapons and Control Engineering Army Academy of Armored ForcesBeijing100072China

One of the main challenges for multi-wheel hub motor driven vehicles is the coordination of individual drivetrains to improve mobility and stability in the steering *** paper proposes a dual-steering mode based on direct yaw moment control for enhancing vehicle steering ability in complex environ *** control system is designed as a hierarchical structure,with a yaw moment decision layer and a driving force distribution *** the higher-level layer,the objective optimization function is con-structed to obtain the slip steering ratio,which represents the degree of vehicle slip steering in the dual-steering *** moment controller using active disturbance rejection control theory is designed for continuous yaw rate *** the actual yaw rate of the vehicle deviates from the reference yaw rate obtained by the vehicle reference model and the slip steering ratio,the yaw moment controller isactuated to determine the yaw moment demand for vehicle *** the lower-level layer,there is a torque distribution controller based on distribution rules,which meets the requirement of yaw moment demand without affecting the total longitudinal driving force of the *** verifying the validity and feasibility of the dual-steering mode,simulations were conducted on the hardware-in-loop real-time simulation ***,corresponding real vehicle tests were carried out on an eight-wheel prototype *** results were generally consistent with the simulation results,thereby demon-strating that the proposed dual-steering mode reduces steering radius and enhances the steering per-formance of the vehicle.

关键词： Multi-wheel hub motor driven vehide Dual-steering mode Direct ya w moment control Real-time simulation

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A convergent mean shift algorithm to select targets for LAMOST

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Research in Astronomy and Astrophysics 2009年第7期9卷 803-811页

作者： guang-wei Li Gang Zhao National Astronomical Observatories Chinese Academy of Sciences Beijing 100012 China

This paper firstly finds that the Mean Shift Algorithm used by the Observation Control System （OCS） Research Group of the University of Science and Technology of China in Survey Strategy System 2.10 （SSS2.10） to select targets for the Large Sky Area Multi-Object Fiber Spectroscopic Telescope （LAMOST） is not convergent in theory. By carefully studying the mathematical formulation of the Mean Shift Algorithm, we find that it tries to find a point where some objective function achieves its maximum value; the Mean Shift Vector can be regarded as the ascension direction for the objective function. If we regard the objective function as the numerical description for the imaging quality of all targets covered by the focal panel, then the Mean Shift Algorithm can find the place where the imaging quality is the best. So, the problem of selecting targets is equal to the problem of finding the place where the imaging quality is the best. In addition, we also give some effective heuristics to improve computational speed and propose an effective method to assign point sources to the respective fibers. As a result, our program runs fast, and it costs only several seconds to generate an observation.

关键词： methods: data analysis - methods: statistical

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Comparison of kinetic models for isothermal CO_2 gasification of coal char–biomass char blended char

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International Journal of Minerals,Metallurgy and Materials 2015年第4期22卷 363-370页

作者： Hai-bin Zuo wei-wei Geng Jian-liang Zhang guang-wei Wang State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing School of Metallurgical and Ecological Engineering University of Science and Technology Beijing

This study investigated the isothermal gasification reactivity of biomass char （BC） and coal char （CC） blended at mass ratios of 1：3, 1：1, and 3：1 via isothermal thermogravimelric analysis （TGA） at 900, 950, and 1000℃ under CO2. With an increase in BC blending ra- tio, there were an increase in gasification rate and a shortening of gasification time. This could be attributed to the high specific surface area of BC and the high uniformity of carbon structures in CC when compared to those in BC. Three representative gas-solid kinetic models, namely, the volumetric model （VM）, grain model （GM）, and random pore model （RPM）, were applied to describe the reaction behavior of the char. Among them, the RPM model was considered the best model to describe the reactivity of the char gasification reaction. The activa- tion energy of BC and CC isothermal gasification as determined using the RPM model was found to be 126.7 kJ/mol and 210.2 kJ/mol, re- spectively. The activation energy was minimum （123.1 kJ/mol） for the BC blending ratio of 75%. Synergistic effect manifested at all mass ratios of the blended char, which increased with the gasification temperature.

关键词： ironmaking coal char biomass gasification kinetic models synergistic effect

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Emerging approaches to probing ion channel structure and function

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Neuroscience Bulletin 2012年第4期28卷 351-374页

作者： wei-guang Li Tian-Le Xu Neuroscience Division Department of Biochemistry and Molecular Cell BiologyInstitute of Medical SciencesShanghaiJiao Tong University School of MedicineShanghai 200025China

Ion channels,as membrane proteins,are the sensors of the *** act as the first line of communication with the world beyond the plasma membrane and transduce changes in the external and internal environments into unique electrical signals to shape the responses of excitable *** of their importance in cellular communication,ion channels have been intensively studied at the structural and functional ***,we summarize the diverse approaches,including molecular and cellular,chemical,optical,biophysical,and computational,used to probe the structural and functional rearrangements that occur during channel activation（or sensitization）,inactivation（or desensitization）,and various forms of *** emerging insights into the structure and function of ion channels by multidisciplinary approaches allow the development of new pharmacotherapies as well as new tools useful in controlling cellular activity.

关键词： ion channel structure and function mutagenesis covalent modification voltage-clamp fluorometry computational chemistry

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Flow Injection Determination of Oxalate Based on Its Catalytic Effect on the Oxidation of p-Chloride Aniline by Dichromate

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Chemical Research in Chinese Universities 2001年第3期17卷 253-258页

作者： LI Li-jun wei Hong-guang ZHANG Ying guangxi Institute of Technology Liuzhou 545006P.R.China

In a sulfuric acid medium, oxalate exhibits a strong catalytic effect on the oxidation of p-chloride aniline(ClBN) by dichromate, and the red oxidation product of ClBN has a maximum absorhancy at 520 nm. Based on this founding, a new FI method for determining oxalate was developed. A calibration curve of oxalate in the range of 0.40—17.0μg/mL was obtained. The detection limit was 0.10μg/mL. Sampling rate was 103-samples/h. The possible interference by the co-existing substances or ions was examined. This new method was applied to the determination of micro amounts of oxalate in real samples with satisfactory results.

关键词： FIA Oxalate p-Chloro aniline Potassium dichromate

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Optimizing mechanical properties of HIPS fabricated with low-cost desktop 3D printers:investigating the impact of process parameters

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Advances in Manufacturing 2024年第2期12卷 379-395页

作者： Jin-Ting Xu guang-wei Zhang Man-Man Chen School of Automotive Engineering Dalian University of TechnologyDalian116024People’s Republic of China

Recently,low-cost desktop three-dimensional(3D)printers,employing the fused deposition modeling(FDM)technique,have gained widespread ***,most users cannot test the strength of printed parts,and little information is available about the mechanical properties of printed high-impact polystyrene(HIPS)parts using desktop 3D *** this study,the user-adjustable parameters of desktop 3D printers,such as crisscross raster orientation,layer thickness,and infill density,were *** experimental plans were designed using the Box-Behnken method,and tensile,3-point bending,and compression tests were carried out to determine the mechanical responses of the printed *** prediction models of the process parameters were regressed to produce the optimal combination of process *** experimental results showcase that the crisscross raster orientation has significant effects on the flexural and compression strengths,but not on the tensile *** an increase in the layer thickness,the tensile,flexural,and compression strengths first decreased and then increased,reaching their minimum values at approximately 0.16 mm layer *** addition,they all increased with an increase of infill *** was demonstrated that when the raster orientation,layer thickness,and infill density were 13.08°/–76.92°,0.09 mm,and 80%,respectively,the comprehensive mechanical properties of the printed HIPS were *** results can help end-users of desktop 3D printers understand the effects of process parameters on the mechanical properties,and offer practical suggestions for setting proper printing parameters for fabricating HIPS parts.

关键词： Desktop three-dimensional(3D)printers Fused deposition modeling(FDM) High-impact polystyrene(HIPS) Process parameters

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Development of two-dimensional numerical wave tank based on lattice Boltzmann method

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Journal of Hydrodynamics 2020年第1期32卷 116-125页

作者： guang-wei Liu Qing-he Zhang Jin-feng Zhang State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin UniversityTianjin 300072China

A 2-D numerical wave tank(NWT)is developed using the lattice Boltzmann method(LBM)and a multi-relaxation-time(MRT)collision model coupled with an algebraic volume of fluid(VOF)scheme for free surface *** external force based on the momentum source function is used to generate the waves,and a zone of porous media is used to absorb the *** simulations of the progressive and standing waves show that the NWT can generate stable wave trains in agreement with the analytical solutions and eliminate the re-reflection *** NWT is used to simulate two problems encountered in practice,namely:the wave transformation over a submerged breakwater and the wave runup on a sea *** numerical predictions are in good agreement with the measured data.

关键词： Numerical wave tank(NWT) wave generation method volume of fluid(VOF) lattice Boltzmann method(LBM)

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Phase Transformation and Its Effects on Mechanical Properties and Pitting Corrosion Resistance of 2205 Duplex Stainless Steel

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Journal of Iron and Steel Research International 2010年第11期17卷 67-72页

作者： ZOU De-ning HAN Ying ZHANG wei FAN guang-wei School of Metallurgy and Engineering Xi'an University of Architecture and Technology Xi'an 710055 Sbaanxi China State Key Laboratory for Mechanical Behavior of Metal Materials Xi'an Jiaotong University Xi'an 710049 Shaanxi China State Key Laboratory of Advanced Stainless Steel Materials Taigang Stainless Steel Co Ltd Taiyuan 030003 Shanxi China

The effects of phase transformation on mechanical properties and pitting corrosion of 2205 duplex stainless steel were investigated. The amount of a phase in the test specimen varied up to a maximum of 6 % by thermal treatment at 850 ℃ for up to 60 min. The results showed that ~ phase markedly increased the hardness and decreased the impact toughness of the test steel. But the increasing tendency of the ultimate tensile strength and the yield strength was not obvious, while the total elongation abruptly decreased with the aging time from 5 to 60 min. SEM impact microfractograph analysis revealed that the types of impact fracture changed from ductile mode to transcrystalline mode when the specimens were aged for 5-60 min. Furthermore, the extent of pitting potential reducing was found to be strongly temperature dependent, more pronounced at the higher temperature. During the incubation period of σ phase nucleation, the pitting corrosion test temperature and the aging time had collaborative effects on evidently displacing the pitting potential towards less noble values. After 15 min, the higher temperature contributed more to decreasing the pitting potential than the aging time.

关键词： duplex stainless steel phase transformation mechanical property pitting corrosion

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