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One-dimensional analysis of the coupling between diffusion and deformation in a bilayer electrode

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Acta Mechanica Sinica 2019年第3期35卷 589-599页

作者： Yaohong suo Fuqian Yang School of Mechanical Engineering and Automation Fuzhou UniversityFuzhou 350108China Department of Chemical and Materials Engineering University of KentuckyLexingtonKY 40506USA State Key Lab for Strength and Vibration of Mechanical Structures School of AerospaceXi'an Jiaotong UniversityXi'an 710049China

Diffusion-induced deformation during electrochemical cycling plays an important role in determining structural durability of the electrodes in lithium-ion batteries. In this work, we investigate the coupling between diffusion and stress in the boundary conditions of a bilayer electrode, and analyze the evolution of the lithium concentration and stress. Numerical simulations are performed under four different combinations of the boundary conditions between diffusion and mechanical deformation. The stress distributes uniformly in the bilayer electrode for all four cases. The concentration of lithium at the interface is discontinuous for the cases with fixed boundary conditions and is continuous for the cases with a surface at stress-free state. For the bilayer electrode fixed at both surfaces, the magnitude of the stress in the bilayer electrode increases with the increase of the diffusion time. This study reveals the importance of incorporating the coupling between diffusion and stress in the boundary condition in the analysis of the structural durability of lithium-ion batteries and in the design of multilayered and/or gradient electrodes.

关键词： Diffusion-induced deformation Bilayer electrode Lithium-ion battery

Robust PolInSAR optimal interferogram estimation method based on generalized scattering vector

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Journal of Systems Engineering and Electronics 2017年第3期28卷 457-471页

作者： Zhiyong suo Ming Li National Lab of Radar Singal Processing Xidian UniversityXi’an 710071China Beijing Aerospace Automatic Control Institute Beijing 100854China National Key Laboratory of Science and Technology on Aerospace Intelligent Control Beijing 100854China

For the polarimetric synthetic aperture radar interferometry (PoIInSAR) processing, it is necessary to coregister all the images, including the coregistration of polarimetric SAR images and the coregistration of interferometric SAR images. Otherwise, the performance of the estimated optimal interferograms will be deteriorated. A generalized scattering vector (GSV) model is proposed to execute the PoIInSAR optimal interferograms estimation. The generalized scattering vector is constructed by the Pauli scattering vectors of the processing pixel and the surrounding pixels. Even though there are coregistration errors, all the polarimetric information of the current processing pixel is entirely included in the generalized scattering vector. Therefore, the GSV-based method can automatically recover the optimal scattering mechanisms of the processing pixel with coregistration errors either in interferoemetric channels or polarimetric channels. Theoretical analysis and processing results of simulated PoISARPro data and real PALSAR data validate the effectiveness and correctness of the proposed method.

关键词： polarimetric synthetic aperture radar interferometry (PoIInSAR) generalized scattering vector (GSV) optimal interferogram coregistration error Pauli basis

A Quasiconcavity Property for the Heat Equation in a Convex Ring

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Communications in Mathematics and Statistics 2020年第4期8卷 453-462页

作者： Jingjing suo School of Mathematical Sciences University of Science and Technology of ChinaHefei 230026People’s Republic of China

We give an exposition of a result of Borell(Commun Math Phys 86:143-147,1982)that the probability function that Brownian motion hits the inner boundary before time t and before hitting the outer boundary is a space-ti... 详细信息

关键词： Heat equation Quasiconcavity Maximum principle Comparison method

VISCOELASTICITY AND POROELASTICITY IN ELASTOMERIC GELS

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Acta Mechanica Solida Sinica 2012年第5期25卷 441-458页

作者： Yuhang Hu Zhigang suo (School of Engineering and Applied Sciences Kavli Institute for Nanobio Science and Technology Harvard University Cambridge MA 02138 USA)

An elastomeric gel is a mixture of a polymer network and a solvent. In response to changes in mechanical forces and in the chemical potential of the solvent in the environment, the gel evolves by two concurrent molecular processes： the conformational change of the network, and the migration of the solvent. The two processes result in viscoelasticity and poroelasticity, and are characterized by two material-specific properties： the time of viscoelastic relaxation and the effective diffusivity of the solvent through the network. The two properties define a material- specific length. The material-specific time and length enable us to discuss macroscopic observations made over different lengths and times, and identify limiting conditions in which viscoelastic and poroelastic relaxations have either completed or yet started. We formulate a model of homogeneous deformation, and use several examples to illustrate viscoelasticity-limited solvent migration, where the migration of the solvent is pronounced, but the size of the gel is so small that the rate of change is limited by viscoelasticity. We further describe a theory that evolves a gel through inhomogeneous states. Both infinitesimal and finite deformation are considered.

关键词： elastomer gel viscoelasticity poroelasticity creep stress relaxation

A FINITE ELEMENT METHOD FOR DIELECTRIC ELASTOMER TRANSDUCERS

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Acta Mechanica Solida Sinica 2012年第5期25卷 459-466页

作者： Shaoxing Qu Zhigang suo Department of Engineering Mechanics Zhejiang UniversityHangzhou 310027China Soft Matter Research Center(SMRC) Zhejiang UniversityHangzhou 310027China School of Engineering and Applied Sciences Harvard UniversityCambridgeMA 02138USA

We present a finite element method for dielectric elastomer （DE） transducers based on the nonlinear field theory of DE. The method is implemented in the commercial finite element software ABAQUS, which provides a large library functions to describe finite elasticity. This method can be used to solve electromechanical coupling problems of DE transducers with complex configurations and under inhomogeneous deformation.

关键词： finite element method dielectric elastomer electromechanical coupling

Influence of Alloying Element Addition on Cu–Al–Ni High-Temperature Shape Memory Alloy without Second Phase Formation

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Acta Metallurgica Sinica(English Letters) 2016年第9期29卷 884-888页

作者： Xin Zhang Qing-suo Liu School of Materials Science and Engineering Tianjin University of TechnologyTianjin 300384China

In this study, the effects of rare earth Gd and Fe elements on the microstructure, the mechanical properties and the shape memory effect of Cu-11.9Al-3.8Ni high-temperature shape memory alloy were investigated by optical microscopy, scanning electron microscopy, X-ray diffraction and compression test. The microstructure observation results showed that both Cu-11.9Al-3.8Ni-0.2Gd and Cu-11.9Al-3.8Ni-2.0Fe-0.2Gd alloys displayed the fine grain and single- phase fll1 martensite, and their grain size was about several hundred microns, one order of the magnitude smaller than that of Cu-11.9Al-3.8Ni alloy. The compression test results proved that the mechanical properties of Cu-11.9Al-3.8Ni alloy were dramatically improved by alloying element additions due to grain refinement and solid solution strengthening, and the compressive fracture strains of Cu-11.9Al-3.8Ni-0.2Gd and Cu-ll.9Al-3.8Ni-2.0Fe-0.2Gd were 12.0% and 17.8%, respectively. When the pre-straln was 10%, the reversible strains of 5.4% and 5.9% were obtained for Cu-11.9Al-3.8Ni- 0.2Gd and ***-2.0Fe-0.2Gd alloys after being heated to 500 ℃ for 1 rain, and the obvious two-way shape memory effect was also observed.

关键词： High-temperature shape memory alloys Shape memory effect Microstructure Cu-Al-Nialloy

Immobilization study of biosorption of heavy metal ions onto activated sludge

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Journal of Environmental Sciences 2004年第4期16卷 640-645页

作者： WUHai-suo ZHANGAi-qiang WANGLian-sheng StateKeyLaboratoryofPollutionControlandResourcesReuse SchooloftheEnvironmentNanjingUniversityNanjing210093China

Activated sludge was immobilized into Ca-alginate beads via entrapment, and biosorption of three heavy metal ions, copper(Ⅱ), zinc(Ⅱ), and chromimum(Ⅱ), from aqueous solution in the concentration range of 10\_100 mg/L was studied by using both entrapped activated sludge and inactivated free biomass at pH≤5. A biphasic metal adsorption pattern was observed in all immobilized biomass experiments. The biosorption of metal ions by the biosorbents increased with the initial concentration increased in the medium. The adsorption rate of immobilized pre-treated activated sludge(PAS) was much lower than that of free PAS due to the increase in mass transfer resistance resulting from the polymeric matrix. Biosorption equilibrium of beads was established in about 20 h and the adsorbed heavy metal ions did not change further with time. No significant effect of temperature was observed in the test for free biomass while immobilized PAS appeared to be strong temperature dependent in the test range of 10 and 40℃. Besides, the content of activated sludge in the calcium alginate bead has an influence on the uptake of heavy metals. The sorption equilibrium was well modeled by Langmuir isotherm, implying monomolecular adsorption mechanism. Carboxyl group in cell wall played an important role in surface adsorption of heavy metal ions on PAS.

关键词： biosorption alginate beads immobilization heavy metal activated sludge wastewater treatment

Fabrication of TiO_2 Nanotube Arrays by Rectified Alternating Current Anodization

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Journal of Materials Science & Technology 2015年第1期31卷 23-29页

作者： Han Song Jing Shang Chen suo State Key Joint Laboratory of Environmental Simulation and Pollution Control College of Environmental Sciences and EngineeringPeking University

Anodization is a popular method of preparing TiO2nanotube array films（TiNTs） by using direct current（DC）power as the driving *** this study,three driving voltage modes,namely,the sine alternating current（sine） mode,the full-wave rectification of sine waves via four diodes（sine-4D,where D means diode） mode,and the DC mode,were used to prepare TiNTs by *** 20 V,TiNTs were formed under sine-4D mode but only irregular porous TiO2films were formed under DC *** 50 V,TiNTs formed under both the sine-4D and DC *** TiNTs formed in the sine mode anodization at either 20 or 50 *** with the DC mode,the sine-4D mode required a lower oxidation voltage for TiNT formation,which suggests that sine-4D is an economical,convenient,and efficient driving voltage for TiNT preparation by *** morphologies and structures of TiNT samples anodized at 50 V in the sine-4D and DC modes at different oxidation time（1,5,10,30,60,and 120 min） were *** growth processes were similar between the studied ***,the growth rate of the films was faster under the sine-4D mode than the DC mode during the first 30 min of anodization.

关键词： TiO2nanotube Anodization Alternating current Growt

Commutative Rings Whose Zero-divisor Graph Is a Proper Refinement of a Star Graph

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Acta Mathematica Sinica,English Series 2011年第6期27卷 1221-1232页

作者： Qiong LIU Tong suo WU Department of Mathematics and Physics Shanghai University of Electric Power Shanghai 201300 P. R. China Department of Mathematics Shanghai Jiaotong University Shanghai 200240 P. R. China

A graph is called a proper refinement of a star graph if it is a refinement of a star graph, but it is neither a star graph nor a complete graph. For a refinement of a star graph G with center c, let G＊ be the subgraph of G induced on the vertex set V（G）／ {c or end vertices adjacent to c}. In this paper, we study the isomorphic classification of some finite commutative local rings R by investigating their zero-divisor graphs G=Г（R）, which is a proper refinement of a star graph with exactly one center c. We determine all finite commutative local rings R such that G＊ has at least two connected components. We prove that the diameter of the induced graph G＊ is two if Z（R）2 ≠{0}, Z（R）3 = {0} and Gc is connected. We determine the structure of R which has two distinct nonadjacent vertices a, fl C Z（R）＊／{c} such that the ideal [N（a）N（β）]{0} is generated by only one element of Z（R）＊／{c}. We also completely determine the correspondence between commutative rings and finite complete graphs Kn with some end vertices adjacent to a single vertex of Kn.

关键词： Commutative rings zero-divisor graph minimal generating set connected component