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Free vibration of functionally graded beams based on both classical and first-order shear deformation beam theories

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Applied Mathematics and Mechanics(English Edition) 2014年第5期35卷 591-606页

作者：李世荣万泽青张静华 School of Civil Science and Engineering Yangzhou University

The free vibration of functionally graded material （FGM） beams is studied based on both the classical and the first-order shear deformation beam theories. The equations of motion for the FGM beams are derived by considering the shear deforma- tion and the axial, transversal, rotational, and axial-rotational coupling inertia forces on the assumption that the material properties vary arbitrarily in the thickness direction. By using the numerical shooting method to solve the eigenvalue problem of the coupled ordinary differential equations with different boundary conditions, the natural frequen- cies of the FGM Timoshenko beams are obtained numerically. In a special case of the classical beam theory, a proportional transformation between the natural frequencies of the FGM and the reference homogenous beams is obtained by using the mathematical similarity between the mathematical formulations. This formula provides a simple and useful approach to evaluate the natural frequencies of the FGM beams without dealing with the tension-bending coupling problem. Approximately, this analogous transition can also be extended to predict the frequencies of the FGM Timoshenko beams. The numerical results obtained by the shooting method and those obtained by the analogous transformation are presented to show the effects of the material gradient, the slenderness ratio, and the boundary conditions on the natural frequencies in detail.

关键词： functionally graded material (FGM) Timoshenko beam free vibration,shooting method analogous transformation

Infiltration by monocytes of the central nervous system and its role in multiple sclerosis: reflections on therapeutic strategies

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Neural Regeneration Research 2025年第3期20卷 779-793页

作者： Guangyong Zhang qing Yao Chubing Long Pengcheng Yi Jiali Song Luojia Wu Wei wan Xiuqin Rao Yue Lin Gen Wei Jun Ying Fuzhou Hua Department of Anesthesiology the Second Affiliated Hospital of Nanchang UniversityNanchangJiangxi ProvinceChina Key Laboratory of Anesthesiology of Jiangxi Province NanchangJiangxi ProvinceChina

Mononuclear macrophage infiltration in the central nervous system is a prominent feature of neuroinflammation. Recent studies on the pathogenesis and progression of multiple sclerosis have highlighted the multiple roles of mononuclear macrophages in the neuroinflammatory process. Monocytes play a significant role in neuroinflammation, and managing neuroinflammation by manipulating peripheral monocytes stands out as an effective strategy for the treatment of multiple sclerosis, leading to improved patient outcomes. This review outlines the steps involved in the entry of myeloid monocytes into the central nervous system that are targets for effective intervention: the activation of bone marrow hematopoiesis, migration of monocytes in the blood, and penetration of the blood–brain barrier by monocytes. Finally, we summarize the different monocyte subpopulations and their effects on the central nervous system based on phenotypic differences. As activated microglia resemble monocyte-derived macrophages, it is important to accurately identify the role of monocyte-derived macrophages in disease. Depending on the roles played by monocyte-derived macrophages at different stages of the disease, several of these processes can be interrupted to limit neuroinflammation and improve patient prognosis. Here, we discuss possible strategies to target monocytes in neurological diseases, focusing on three key aspects of monocyte infiltration into the central nervous system, to provide new ideas for the treatment of neurodegenerative diseases.

关键词： blood–brain barrier macrophages monocytes multiple sclerosis neuroinflammation review therapy

Numerical Simulations of Liquid-Solid Flows in A Vertical Pipe by MPS-DEM Coupling Method

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China Ocean Engineering 2022年第4期36卷 542-552页

作者： XIE Feng-ze MENG qing-jie wan De-cheng Computational Marine Hydrodynamics Lab(CMHL) School of Naval ArchitectureOcean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Wuhan Second Ship Design and Research Institute Wuhan 430205China

In the process of deep-sea mining,the liquid-solid flows in the vertical transportation pipeline are very *** the present work,an in-house solver MPSDEM-SJTU based on the improved MPS and DEM is developed for the simulation of hydraulic ***,three examples including the multilayer cylinder collapse,the Poiseuille flow and two-phase dam-break are used to validate the precision of the DEM model,the pipe flow model and MPS-DEM coupling model,***,the hydraulic conveying with coarse particles in a vertical pipe is *** solid particle distribution is presented and investigated in ***,the coupling method is successfully applied for the simulation of the liquid-solid flows in a vertical pipe with rotating blades,which shows the stability of the solver under rotating boundary *** fully Lagrangian model is expected to be a new approach for analyzing hydraulic conveying.

关键词： liquid-solid flows MPS DEM vertical pipe rotating boundary conditions

Characteristics of phosphorus fractionated from the sediment resuspension in abrupt expansion flow experiments

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Journal of Environmental Sciences 2010年第10期22卷 1519-1526页

作者： Jun wan ze wang Hezhong Yuan . College of Environmental Science and Engineering Hohai University Nanjing 210098 China College of Water Conservancy and Hydropower Engineering Hohai University Nanjing 210098 China. State Key Laboratory of Lake Sediments Process Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing 210098 China

Phosphorous （P） fraction characteristics in sediment resuspension were investigated under adequately hydrodynamic conditions. Four forms of P in overlying water, including dissolved inorganic P, dissolved total P, total P, and particulate P, and six fractions of P in suspended particulate matter （SPM）, including loosely sorbed P （NH4Cl-P）, redox-sensitive P （BD-P）, aluminum-bound P （Al- P）, organic P （NaOH-nrP）, calcium-bound P （Ca-P） and residual P （Res-P）, were quantified, respectively. Different hydrodynamic conditions resulted in different P form changes. Four states could be ascribed：（1） P desorption by sediment and SPM, and P adsorption by overlying water; （2） P desorption by SPM, and P adsorption by overlying water; （3） P adsorption by SPM, and P desorption by overlying water; and （4） P equilibrium between SPM and overlying water. The contents of P in overlying water acquired peak values in the middle position of the vertical P distribution due to the combined actions of SPM and sediment. P fractions in SPM were in the following order： BD-P 〉 NaOH-nrp 〉 Ca-P 〉 Al-P 〉 Res-P 〉 NH4Cl-P. BD-P in SPM frequently exchanged with P forms in overlying water. Resuspension was favorable to forming Ca-P in SPM.

关键词： phosphorus fractions hydrodynamic conditions suspended particulate matter abrupt expansion flow

Machine learning the nuclear mass

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Nuclear Science and Techniques 2021年第10期32卷 88-100页

作者： ze-Peng Gao Yong-Jia wang Hong-Liang Lu qing-Feng Li Cai-wan Shen Ling Liu College of Physics Science and Technology Shenyang Normal UniversityShenyang 110034China School of Science Huzhou UniversityHuzhou 313000China HiSilicon Research Department Huawei Technologies Co.Ltd.Shenzhen 518000China Institute of Modern Physics Chinese Academy of ScienceLanzhou 730000China

Background:The masses of-2500 nuclei have been measured experimentally;however,>7000 isotopes are predicted to exist in the nuclear landscape from H(Z=1)to Og(Z=118)based on various theoretical *** the mass of the remaining isotopes is a popular topic in nuclear *** learning has served as a powerful tool for learning complex representations of big data in many ***:We use Light Gradient Boosting Machine(LightGBM),which is a highly efficient machine learning algorithm,to predict the masses of unknown nuclei and to explore the nuclear landscape on the neutron-rich side from learning the measured nuclear ***:Several characteristic quantities(e.g.,mass number and proton number)are fed into the LightGBM algorithm to mimic the patterns of the residual δ(Z,A)between the experimental binding energy and the theoret-ical one given by the liquid-drop model(LDM),Duflo–Zucker(DZ,also dubbed DZ28)mass model,finite-range droplet model(FRDM,also dubbed FRDM2012),as well as the Weizsacker–Skyrme(WS4)model to refine these mass ***:By using the experimental data of 80%of known nuclei as the training dataset,the root mean square devia-tions(RMSDs)between the predicted and the experimental binding energy of the remaining 20%are approximately 0.234±0.022,0.213±0.018,0.170±0.011,and 0.222±0.016 MeV for the LightGBM-refined LDM,DZ model,WS4 model,and FRDM,*** values are approximately 90%,65%,40%,and 60%smaller than those of the corresponding origin mass *** RMSD for 66 newly measured nuclei that appeared in AME2020 was also significantly *** one-neutron and two-neutron separation energies predicted by these refined models are consistent with several theoretical predictions based on various physical *** addition,the two-neutron separation energies of several newly measured nuclei(e.g.,some isotopes of Ca,Ti,Pm,and Sm)pre-dicted with LightGBM-refined mass models are also in good agreement with

关键词： Nuclear mass Machine learning Binding energy Separation energy

Phase selection and performance of Mg–Cu–Y amorphous composite with different Mg/Cu ratios

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Rare Metals 2014年第1期33卷 91-94页

作者： Di-qing wan School of Mechanical and Electronical Engineering East China Jiaotong University

In this article, Mg-Cu-Y alloys with two dif- ferent Mg/Cu ratios （in at%） were prepared using a water- cooled copper mold. Scanning electron microscopy and X-ray diffraction were applied to analyze the microstructure and phase composition. Moreover, corrosion resistance and wear resistance were studied systematically. The results show that both Mg65Cu25Ylo and Mg60Cu30Ylo alloys could form a composition of crystalline and amorphous phases. Although the microstructure of Mg65Cu25Ylo con- sists of an amorphous phase and ：t-Mg, Mg2Cu, and Cu2Y crystalline phases, the microstructure of Mg60Cu30Ylo alloy mainly consists of the amorphous phase and ：t-Mg, Mg2Cu. With reducing Mg/Cu ratio, the alloys have better corrosion resistance and wear resistance. The mechanism has also been discussed in detail.

关键词： Mg-Cu-Y alloy Amorphous composites Corrosion resistance Wear resistance

Strain amplitude-dependent internal friction of as-cast high damping magnesium alloy during cyclic vibration

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Rare Metals 2013年第1期32卷 25-28页

作者： Di-qing wan Key Laboratory of Ministry of Education for Conveyance and Equipment East China Jiaotong University

An investigation on strain amplitude-dependent internal friction （IF） of an as-cast high damping Mg-7 wt% Ni alloy was carried out. In the range of our tested strain amplitudes, whether the strain amplitude is increasing or decreasing, the strain amplitude-dependent IF curve can be divided into two stages： one is the strain amplitude weakly dependent part and the other is the strain amplitude strongly dependent part. However, after several cyclic vibrations, the IF values measured during the strain amplitude increasing are smaller than those obtained during the strain amplitude decreasing. The phenomenon is also observed at 100 C. Partial dislocations generate a short-range slip under the cyclic stress to be responsible for it.

关键词： Magnesium alloys Strain amplitude Internal friction

Stirred casting Al–Pb monotectic alloys with high damping capacity

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Rare Metals 2015年第8期34卷 560-563页

作者： Di-qing wan Key Laboratory of Ministry of Education for Conveyance and Equipment East China Jiaotong University

In this study, the stirred casting with various processing parameters, such as stirring temperature and stirring speeds, was carried out on the Al–Pb monotectic alloys in order to make Pb particles distribute much more uniformly. More importantly, their damping capacities were systematically studied. The results show tha mechanical stirring can not only make Pb in the aluminum matrix uniformly distribute but also dynamically influence the damping capacity of this alloy system. The Al–Pb alloy was prepared under a slow speed at solid–liquid temperature region, wherein high volume fraction of Pb in alloy could be obtained. The high volume fraction of Pb gives high overall damping capacity. The dislocation damping and interface damping theories are mainly dominated to the alloys.

关键词： Al–Pb alloy Mechanical stirring Damping capacity

Vector quantization: a review

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Frontiers of Information Technology & Electronic Engineering 2019年第4期20卷 507-524页

作者： ze-bin WU Jun-qing YU Department of Computer Science and Technology Huazhong University of Science and Technology Center of Network and Computation Huazhong University of Science and Technology

Vector quantization(VQ) is a very effective way to save bandwidth and storage for speech coding and image coding. Traditional vector quantization methods can be divided into mainly seven types, tree-structured VQ,direct sum VQ, Cartesian product VQ, lattice VQ, classified VQ, feedback VQ, and fuzzy VQ, according to their codebook generation procedures. Over the past decade, quantization-based approximate nearest neighbor(ANN)search has been developing very fast and many methods have emerged for searching images with binary codes in the memory for large-scale datasets. Their most impressive characteristics are the use of multiple codebooks. This leads to the appearance of two kinds of codebook: the linear combination codebook and the joint codebook. This may be a trend for the future. However, these methods are just finding a balance among speed, accuracy, and memory consumption for ANN search, and sometimes one of these three suffers. So, finding a vector quantization method that can strike a balance between speed and accuracy and consume moderately sized memory, is still a problem requiring study.

关键词： Approximate nearest neighbor search Image coding Vector quantization