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Preparation of Modified Composite Nanofiltration Membrane Synergistically Using Carboxylic Multi- walled Carbon Nanotube and β-cyclodextrin

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 232-239页

作者： LIU Peng MAO Junpeng FANG Yanfeng YU Yunwu CHEN Changxiu TANG Ning WAN Ye GU Yaxin LIU Yunxue wang lihua School of Materials Science and Engineering Shenyang Jianzhu UniversityShenyang 110168China

A new modified blend ultrafiltration(UF)membrane with good hydrophilicity,high porosity and excellent anti-fouling performance was developed by using carboxylic multi-walled carbon nanotube(CMWCNT)as casting solution ***,a composite nanofiltration(NF)membrane with large water flux and good retention rate was fabricated by using the PVDF/CMWCNT blend UF membrane as the substrate,and polyvinyl alcohol(PVA),β-cyclodextrin(β-CD)and polyethylenimine(PEI)as the coating *** results show that with the appropriate addition of CMWCNT in the casting solution,the surface roughness,porosity and recovery rate of the PVDF/CMWCNT blend UF membrane is obviously *** water flux of blend UF membrane is significantly improved when the CMWCNT content increases from 0 wt%to 0.2 wt%.The water flux of blend UF membrane with 0.2 wt%CMWCNT is 162.7 L/(m^(2)·h),which is 44.3%higher than that of the pure PVDF ***β-CD content is 0.8 wt%,the retention rate of Congo red by PVDF/CMWCNT/β-CD composite NF membrane reaches 98.7%,which is 28.3%higher than that of single PVA/PEI modified *** research will provide a new idea and simple method for developing novel high-performance composite NF membranes.

关键词： CMWCNT cyclodextrin nanofiltration membrane

Layer-element analysis of multilayered saturated soils subject to axisymmetric vertical time-harmonic excitation

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Applied Mathematics and Mechanics(English Edition) 2017年第9期38卷 1295-1312页

作者： Zhiyong AI lihua wang Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationCollege of Civil EngineeringTongji UniversityShanghai 200092China

The analytical layer-elements for a single poroelastic soil layer and the underlying half-space are established using an algebraic manipulation and Hankel trans- form. According to the boundary conditions and adjacent continuity conditions of general stresses and displacements, a global matrix equation in the transform domain for multi- layered saturated soil media is assembled and solved. Solutions in the frequency domain can be further obtained with an inverse Hankel transform. Numerical examples are used to examine accuracy of the present method and demonstrate effects of soil parameters and load conditions on dynamic responses of the multilayered poroelastic saturated soils.

关键词： multilayered saturated soil axisymmetric vertical excitation steady statedynamic response analytical layer-element method

Percolation transport and magnetic transitions in a phase-separated manganite La_(0.55)Ca_(0.45)MnO_3

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Science China(Technological Sciences) 2011年第9期54卷 2315-2320页

作者： LI Guang wang lihua School of Physics and Materials Science Anhui Key Laboratory of Information Materials and Devices Anhui University Hefei 230039 China

The structural, electronic and magnetic properties of La0.55Ca0.45MnO3 were measured. A rapid change of lattice parameters appeared around 190 K associated with the az2 orbital ordering and charge ordering （CO） states that were reflected by both magnetization and resistivity. Great difference of magnetizations between the field-cooling （FC） and zero-field-cooling （ZFC） modes below the charge ordering temperature Too in high magnetic field （H〉4 T） was clearly seen. A field of 5 T （threshold field） is sufficient to completely destroy the antiferromagnetic （AFM） CO state for FC mode in magnetization while it is not the case for ZFC mode. A much larger field （larger than 10 T from ZFC resistivity data） is needed to destroy the CO state for ZFC mode. This could be explained by the coexistence and transformation of two phases reported by Huang et al. For ZFC mode, with increasing H, Tco gradually moves to low temperature regime and the relationship between the critical field Hc （0） to destroy CO state and Tco conforms to a power law Hc = Hc（0）（1 - T/Tco（0））^γ, where Hc （0） is the critical field to destroy the CO state at 0 K, and Too （0） is the CO temperature in zero field.

关键词： manganites phase transition magnetic structure

Complex Modal Analysis for the Time-Variant Dynamical Problem of Rotating Pipe Conveying Fluid

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Computer Modeling in Engineering & Sciences 2018年第1期114卷 1-18页

作者： lihua wang Zheng Zhong School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai200092P.R.China

A semi-analytical form of complex modal analysis is proposed for the time-variant dynamical problem of rotating pipe conveying fluid *** complex mode superposition method is introduced for the dynamic analysis in the time and frequency domains,in which appropriate orthogonality conditions are constructed to decouple the time-variant equation of ***,complex frequencies and modes of vibration are analytically formulated and the variations of frequencies and damping of the system are *** time-variant example of rotating pipe conveying fluid illustrates the effectiveness and accuracy of this ***,the proposed solution scheme is also applicable to other similar time-variant dynamical problems.

关键词： Semi-analytical form complex modal analysis time-variant dynamical problem rotating pipe conveying fluid

Direct calculation of voidage in the fine-grid CFD-DEM simulation of fluidized beds with large particles

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Particuology 2018年第5期16卷 23-33页

作者： lihua wang Jie Ouyang Chuntao Jiang Department of Applied Mathematics Northwestern Polytechnical UniversityXi'an 710129China

Voidage is important in determining the hydrodynamic behavior of a fluidized bed and estimating the drag force,Exact calculation methods are limited,especially in terms of determining the intersection bf a particle and cell,This paper presents a method of directly calculating ***,a judgment criterion of particle-cell overlap,which relies on the relationship of the distance from the particle to a cell face,edge,or vertex,is *** cases of the overlap volume of a particle and cell are then ascribed to a unified formula in the framework of the cuboid cell,This formula relies on the volume of two kinds of segments named the hemispherical segment and quarter-spherical *** presented method is validated by calculating the voidage of simple cubic ***,a three-dimensional fluidized bed with large particles is simulated and the results of numerical simulation are compared against experimental and simulation results reported in the *** numerical results are in good agreement with corresponding experimental data,and demonstrate the accuracy and reliability of the presented method in the three-dimensional simulation of fluidized beds.

关键词： Voidage Direct calculation Computational fluid dynamics-discrete element method Fluidized beds

Theoretical analysis of a new segmented anchoring style in weakly cemented soft surrounding rock

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International Journal of Mining Science and Technology 2016年第3期26卷 401-407页

作者： Zhao Zenghui wang Weiming wang lihua Shandong Provincial Key Laboratory of Civil Engineering Disaster Prevention and Mitigation Shandong University of Science & Technology State Key Laboratory of Mining Disaster Prevention and Control Co-founded by Shandong Province and the Ministry of Science & Technology College of Mining and Safety Engineering Shandong University of Science & Technology College of Civil Engineering and Architecture Shandong University of Science & Technology

According to the tensile failure of rock bolt in weakly cemented soft rock, this paper presents a new segmented anchoring style in order to weaken the cumulative effect of anchoring force associated with the large deformation. Firstly, a segmented mechanical model was established in which free and anchoring section of rock bolt were respectively arranged in different deformation zones. Then, stress and displacement in elastic non-anchoring zone, elastic anchoring zone, elastic sticking zone, softening sticking zone and broken zone were derived respectively based on neural theory and tri-linear strain softening constitutive model of soft rock. Results show that the anchoring effect can be characterized by a supporting parameter b. With its increase, the peak value of tangential stress gradually moves to the roadway wall, and the radial stress significantly increases, which means the decrease of equivalent plastic zone and improvement of confining effect provided by anchorage body. When b increases to 0.72, the equivalent plastic zone disappears, and stresses tend to be the elastic solutions. In addition, the anchoring effect on the displacement of surrounding rock can be quantified by a normalization factor δ.

关键词： Weakly cemented soft rock Segmented anchorage Strain softening Analytical model

Influence of solvent on ion conductivity of polybenzimidazole proton exchange membranes for vanadium redox flow batteries

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Chinese Journal of Chemical Engineering 2020年第6期28卷 1701-1708页

作者： Yahui wang Kaimin Feng Liming Ding lihua wang Xutong Han Key Laboratory of Green Printing Institute of ChemistryChinese Academy of SciencesBeijing 100190China School of Materials Science and Engineering Tianjin Polytechnic UniversityTianjin 300387China School of Chemistry and Chemical Engineering Beijing Institute of TechnologyBeijing 100081PR China

Polybenzimidazole(PBI)is a kind of proton transport membrane material,and its ion conductivity is a key factor affecting its application in vanadium redox flow batteries(VRFBs).The casting solvent of PBI has a significant influence on the acid doping level of PBI membranes which is closely related to ionic *** this paper,3,3′-diaminobenzidine(DABz)and 4,4′-Dicarboxydiphenylether(DCDPE)were used as raw materials by solution condensation to prepare the PBI with ether bond *** chemical structure of PBI was determined by1H NMR and FT-IR,and the prepared PBI had good solubility which can be dissolved in a variety of *** PBI proton exchange membranes were prepared by solution coating with 5 different solvents of N,N-dimethylformamide(DMF),N,N-dimethylacetamide(DMAc),dimethyl sulfoxide(DMSO),1-methyl-2-pyrrolidone(NMP),methane sulfonic acid(MSA).The effects of different solvents on the ion conductivity and physicochemical properties were discussed in *** results showed that the PBI membrane prepared by using MSA as solvent(the PBI+MSA membrane)exhibits high water uptake,acid doping level and low vanadium ion *** VRFB assembled with the PBI+MSA membrane exhibited higher coulombic efficiency(CE)99.87%and voltage efficiency(VE)84.50%than that of the commercial Nafion115 membrane at100 m A·cm-2,and after 480 cycles,the EE value can still be maintained at 83.73%.The self-discharge time of a single battery was recorded to be as long as 1000 *** experimental data indicated that MSA is the best solvent for casting PBI membrane.

关键词： Polybenzimidazole Solvent Acid doping level Ion conductivity Proton exchange membrane Vanadium redox flow batteries

Surface contact behavior of functionally graded thermoelectric materials indented by a conducting punch

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Applied Mathematics and Mechanics(English Edition) 2021年第5期42卷 649-664页

作者： Xiaojuan TIAN Yueting ZHOU lihua wang Shenghu DING School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghai 200092China School of Mathematics and Statistics Ningxia UniversityYinchuan 750021China

The contact problem for thermoelectric materials with functionally graded properties is *** material properties,such as the electric conductivity,the thermal conductivity,the shear modulus,and the thermal expansion coefficient,vary in an exponential *** the Fourier transform technique,the electro-thermoelastic problems are transformed into three sets of singular integral equations which are solved numerically in terms of the unknown normal electric current density,the normal energy flux,and the contact ***,the complex homogeneous solutions of the displacement fields caused by the gradient parameters are simplified with the help of Euler’s *** addressing the non-linearity excited by thermoelectric effects,the particular solutions of the displacement fields can be *** effects of various combinations of material gradient parameters and thermoelectric loads on the contact behaviors of thermoelectric materials are *** results give a deep insight into the contact damage mechanism of functionally graded thermoelectric materials(FGTEMs).

关键词： thermoelectric material functionally graded property conducting punch conjugate complex root energy flux contact pressure

Impact Dynamics of a Dragonfly Wing

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Computer Modeling in Engineering & Sciences 2020年第3期122卷 889-906页

作者： lihua wang Wenjing Ye Yueting Zhou School of Aerospace Engineering and Applied Mechanics Tongji UniversityShanghaiChina.

The lift force was reported not to be high enough to support the dragonfly’s weight during flight in some conventional investigations,and higher lift force is required for its *** this study,by employing a thin plate model,impact effect is investigated for the wing deformation in dragonfly flapping during *** static displacement is formulated to compare with the dynamical displacement caused by *** governing equation of motion for the impact dynamics of a dragonfly wing is derived based on Newton’s second *** of variables technique and assumed modes method are introduced to solve the resulting ***,lift force is presented for the cases of considering and without considering the impact on the wing flapping which indicates that the impact has prominent effects for the dragonfly’s aerodynamic *** simulations demonstrate that considering the impact effect on the wing flapping can increase the wing deformation,which results in the rise of the lift *** enhanced lift force is of critical importance for the dragonfly’s takeoff.

关键词： Impact dynamics wing deformation thin plate model lift force.