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Mode Ⅲ fracture analysis by Trefftz boundary element method

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Acta Mechanica Sinica 2007年第2期23卷 173-181页

作者： yuhong cui Juan Wang Manicka Dhanasekar Qinghua Qin Department of Mechanics Tianjin UniversityTianjin 300072 China Centre for Railway Engineering Central Queensland UniversityNorth Rockhampton QLD 4702 Australia Department of Engineering Australian National UmversltyCanberra ACT 0200 Australia

This paper presents a hybrid Trefftz （HT） boundary element method （BEM） by using two indirect techniques for mode III fracture problems. Two Trefftz complete functions of Laplace equation for normal elements and a special purpose Trefftz function for crack elements are proposed in deriving the Galerkin and the collocation techniques of HT BEM. Then two auxiliary functions are introduced to improve the accuracy of the displacement field near the crack tips, and stress intensity factor （SIF） is evaluated by local crack elements as well. Furthermore, numerical examples are given, including comparisons of the present results with the analytical solution and the other numerical methods, to demonstrate the efficiency for different boundary conditions and to illustrate the convergence influenced by several parameters. It shows that HT BEM by usingthe Galerkin and the collocation techniques is effective for mode III fracture problems.

关键词： Hybrid Trefftz method. Galerkin technique .Point-collocation technique .Mode III fracture

APPLICATION OF TREFFTZ BEM TO ANTI-PLANE PIEZOELECTRIC PROBLEM

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Acta Mechanica Solida Sinica 2006年第4期19卷 352-364页

作者： Wang Juan cui yuhong Qin Qinghua Jia Jiangying Department of Mechanics Tianjin University Tianjin 30072 China Department of Engineering Australian National University Canberra ACT 0200 Australia

Anti-plane electroelastic problems are studied by the Trefftz boundary element method （BEM） in this paper. The Trefftz BEM is based on a weighted residual formulation and indirect boundary approach. In particular the point-collocation and Galerkin techniques, in which the basic unknowns are the retained expansion coefficients in the system of complete equations, are considered. Furthermore, special Trefftz functions and auxiliary functions which satisfy exactly the specified boundary conditions along the slit boundaries are also used to derive a special purpose element with local defects. The path-independent integral is evaluated at the tip of a crack to determine the energy release rate for a mode Ⅲ fracture problem. In final, the accuracy and efficiency of the Trefftz boundary element method are illustrated by an example and the comparison is made with other methods.

关键词： Trefftz boundary element, point-collocation technique, Galerkin technique, special trial function anti-plane fracture, piezoelectric medium

Helical Fiber Pull-out in Biological Materials

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Acta Mechanica Solida Sinica 2016年第3期29卷 245-256页

作者： Lixin Wang yuhong cui Qinghua Qin Hui Wang Jianshan Wang Tianjin Key Laboratory of Modern Engineering Mechanics & Department of Mechanics Tianjin University Research School of Engineering Australian National University Department of Engineering Mechanics Henan University of Technology

Many biological materials, such as wood and bone, possess helicoid microstructures at microscale, which can serve as reinforcing elements to transfer stress between crack surfaces and improve the fracture toughness of their composites. Failure processes, such as fiber/matrix inter- face debonding and sliding associated with pull-out of helical fibers, are responsible mainly for the high energy dissipation needed for the fracture toughness enhancement. Here we present systemic analyses of the pull-out behavior of a helical fiber from an elastic matrix via the finite element method （FEM） simulation, with implications regarding the underlying toughening mechanism of helicoid microstructures. We find that, through their uniform curvature and torsion, helical fibers can provide high pull-out force and large interface areas, resulting in high energy dissipation that accounts, to a large extent, for the high toughness of biological materials. The helicity of fiber shape in terms of the helical angle has significant effects on the force-displacement relationships as well as the corresponding energy dissipation during fiber pull-out.

关键词： biological materials helicoid microstructures fiber pull-out energy dissipation,toughness

Core-rim structured MXene@SiO_(2)composites as oil-based additives for enhanced tribological properties

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Friction 2024年第8期12卷 1728-1740页

作者： yuhong cui Shenghua XUE Tiantian WANG Shujuan LIU Qian YE Feng ZHOU Weimin LIU State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi'an 710072China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Herein,we have prepared SiO_(2)particles uploaded MXene nanosheets via in-situ hydrolysis of *** to the large number of groups at the edges of MXene,SiO_(2)grows at the edges first,forming MXene@SiO_(2)composites with a unique core-rim *** tribological properties of MXene@SiO_(2)as lubricating additive in 500 SN are evaluated by *** results show that MXene@SiO_(2)can reduce the friction coefficient of 500 SN from 0.572 to 0.108,the wear volume is reduced by 73.7%,and the load capacity is increased to 800 *** superior lubricity of MXene@SiO_(2)is attributed to the synergistic effect of MXene and SiO_(2).The rolling friction caused by SiO_(2)not only improves the bearing capacity but also increases the interlayer distance of MXene,avoiding accumulation and making it more prone to interlayer ***@SiO_(2)is adsorbed on the friction interface to form a physical adsorption film and isolate the friction *** addition,the high temperature and high load induce the tribochemical reaction and form a chemical protection film during in the friction ***,the presence of these protective films results in MXene@SiO_(2)having good lubricating properties.

关键词： Ti3C2Tx MXene SiO_(2)nanoparticles lubricating additives protective film

Performance of a polymerization-based electrochemically assisted persulfate process on a real coking wastewater treatment

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Journal of Environmental Sciences 2024年第12期146卷 149-162页

作者： Suiqin Yang yuhong cui Zhengqian Liu Chao Peng Shiquan Sun Jingjing Yang Mingkui Wang Wuhan National Laboratory for Optoelectronics Huazhong University of Science and TechnologyWuhan 430074China School of Environmental Science and Engineering Huazhong University of Science and TechnologyWuhan 430074China Eawag Swiss Federal Institute of Aquatic Science and TechnologyÜberlandstrasse 133Dübendorf CH-8600Switzerland School of Hydraulic Engineering Changsha University of Science&TechnologyChangsha 410114China Center for Separation and Purification Materials&Technologies Suzhou University of Science and TechnologySuzhou 215009China

Industrial wastewater should be treated with caution due to its potential environmental *** this study,a polymerization-based cathode/Fe^(3+)/peroxydisulfate(PDS)process was employed for the first time to treat a raw coking wastewater,which can achieve simulta-neous organics abatement and recovery by converting organic contaminants into separable solid *** results confirm that several dominant organic contaminants in coking wastewater such as phenol,cresols,quinoline and indole can be induced to poly-merize by self-coupling or *** total chemical oxygen demand(COD)abate-ment from coking wastewater is 46.8%and the separable organic-polymer formed from or-ganic contaminants accounts for 62.8%of the abated *** organic carbon(DOC)abatement of 41.9%is achieved with about 89%less PDS consumption than conventional degradation-based *** conditions such as PDS concentration,Fe3+concen-tration and current density can affect the COD/DOC abatement and organic-polymer yield by regulating the generation of reactive ***-MS result shows that some organic-polymers are substituted by inorganic ions such as Cl^(-),Br^(-),I^(-),NH_(4)^(+),SCN^(-)and CN^(-),suggest-ing that these inorganic ionsmay be involved in the *** specific consump-tion of this coking wastewater treatment is 27 kWh/kg COD and 95 kWh/kg *** values are much lower than those of the degradation-based processes in treating the same coking wastewater,and also are lower than those of most processes previously reported for coking wastewater treatment.

关键词： Polymerization Coking wastewater Organics recovery Advanced oxidation process Water treatment

Laser manufactured-liquid metal nanodroplets intercalated Mxene as oil-based lubricant additives for reducing friction and wear

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Journal of Materials Science & Technology 2024年第20期187卷 169-176页

作者： yuhong cui Guangkai Jin Shenghua Xue Shujuan Liu Qian Ye Feng Zhou Weimin Liu State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityXi’an 710072China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Two-dimensional(2D)material MXene is a research hotspot in lubricating materials because of its unique layered structure,which provides weak interlayer interaction and easy shear ***,the liquid metal nanodroplets intercalated MXene were successfully prepared via pulsed laser treatment and self-assembly ***,zero-dimensional(0D)nano gallium-based liquid metal(GLM)was synthesized by pulsed laser irradiation of bulk Ga_(80)In_(20)in ***,the GLM nanodroplets were loaded onto 2D MXene nanosheets via the effect of electrostatic adsorption to prepare MXene@GLM composite *** as-obtained GLM not only widens the interlayer distance between MXene nanosheets,making it more susceptible to interlayer shear,but also enhances its *** friction test results showed that the MXene@GLM has the best lubrication performance with 1.0 wt%*** coefficient of friction(COF)of base oil PAO-6 can decrease from 0.79 to 0.097,the wear volume is reduced by 90.3%,and the maximum load sustained reaches 950 *** good tribological properties are mainly owing to the synergistic lubrication of GLM and MXene,which can form a continuous and firm tribofilm on the friction contact surface and avoid the direct contact of the friction pair.

关键词： Nano additives Ti_(3)C_(2)T_(x)MXene Gallium-based liquid metal Friction protective film

Synthesis of surface imprinted polymers based on wrinkled flower-like magnetic graphene microspheres with favorable recognition ability for BSA

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Journal of Materials Science & Technology 2021年第15期74卷 203-215页

作者： Zuoting Yang Ke Yang yuhong cui Tariq Shah Mudasir Ahmad Qiuyu Zhang Baoliang Zhang School of Chemistry and Chemical Engineering Northwestern Polytechnical UniversityXi'an710129China Xi'an Key Laboratory of Functional Organic Porous Materials Northwestern Polytechnical UniversityXi'an710072China Sunresins New Materials Co.Ltd. Xi'an710072China

Nowadays,the employing of molecular imprinting technique in the analysis and separation of proteins from complex biological samples has been widely favored by *** enrich the types of surface protein imprinted materials and expand the application fields of graphene materials,novel surface molecular imprinted polymers(MIPs)based on magnetic graphene microspheres Fe_(3)O_(4)@r GO@MIPs are first synthesized in this ***_(3)O_(4)@r GO@MIPs are prepared by oxidative self-polymerization of dopamine on the surface of magnetic graphene(Fe_(3)O_(4)@r GO)composite *** serum albumin(BSA)is selected as protein ***_(3)O_(4)@r GO microspheres with wrinkled flower-like structure are obtained by compounding Fe_(3)O_(4)and graphene oxide in an appropriate ratio via the method of high-temperature reduction *** microspheres exhibit promising dispersibility,high external surface area,rich pore structure,and sufficient magnetic *** advantages not only prevent the agglomeration of imprinted microspheres in the aqueous phase,which is conducive to contact and static adsorption,but also increase the amount of protein ***,sufficient magnetic properties ensure fast and effective separation of the *** the adsorption capacity is increased,the separation procedure becomes *** binding capacity of Fe_(3)O_(4)@r GO@MIPs for BSA can reach 317.58 mg/g within 60 min,and the imprinting factor(IF)is *** importantly,Fe_(3)O_(4)@r GO@MIPs can specifically recognize the target BSA from the mixed proteins and the actual *** is no significant decrease in the adsorption amount,IF,and magnetic properties after eight *** is promising to be used in the separation of proteins from the actual biological samples.

关键词： Wrinkled Flower-like Magnetic graphene microspheres Dopamine BSA Surface protein imprinting

Numerical Study on Helical Fiber Fragmentation in Chiral Biological Materials

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Transactions of Tianjin University 2018年第1期24卷 51-58页

作者： Jianshan Wang Li Yuan Lixin Wang yuhong cui Qinghua Qin Department of Mechanics Tianjin UniversityTianjin 300054China China Automotive Technology and Research Center Tianjin 300300China Research School of Engineering Australian National UniversityCanberra ACT 0200Australia

Chiral microstructures exist widely in natural biological materials such as wood, bone, and climbing tendrils. The helical shape of such microstructures plays an important role in stress transfer between fiber and matrix,and in the mechanical properties of biological materials. In this paper, helical fiber fragmentation behavior is studied numerically using the finite-element method(FEM), and then, the effects of helical shape on fiber deformation and fracture,and the corresponding mechanical mechanisms are investigated. The results demonstrate that, to a large degree, the initial microfibril angle(MFA) determines the elastic deformation and fracture behavior of fibers. For fibers with a large MFA, the interfacial area usually has large values, inducing a relatively low fragment density during fiber fragmentation. This work may be helpful in understanding the relationship between microstructure and mechanical property in biological materials, and in the design and fabrication of bio-inspired advanced functional materials.

关键词： Chiral biological materials Helical fiber Fiber fragmentation Deformation Dissipated energy

Distribution Regularity of Debris Flow and Its Hazard in Upper Reaches of Yangtze River and Other Rivers of Southwestern China

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Wuhan University Journal of Natural Sciences 2007年第4期12卷 619-626页

作者： WEI Fangqiang JIANG yuhong cui Peng DING Mingtao Key Laboratory of Mountain Hazards and Surface Process Chinese Academy of Sciences / Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 Sichuan China

In the upper reaches of Yangtze River and other rivers of southwestern China, the debris flows develop and lead to most serious disasters because of the various landforms, complex geological structures and abundant rainfall. The distribution of debris flows has regularity in the regions with different landform, geological structure, and precipitation. The regularities of distribution of debris flows are as following：（1） distributed in transition belts of different morphologic regions; （2） distributed in the area with strong stream trenching; （3） distributed along fracture zones and seismic belts：（4） distributed in the area with abundant precipitation; （5） distribution of debris flow is azonal. The activity of abundant debris flows not only brings harm to Towns, Villages and Farmlands, Main Lines of Communication, Water-Power Engineering, Stream Channels etc., but also induces strong water and soil loss. According to the present status of debris flow prevention, the problems in disasters mitigation and soil conservancy are found out, and the key works are brought up for the future disasters prevention and soil conservancy.

关键词： upper reaches of Yangtze River southwestern China debris flow water and soil loss distribution and hazards of debris flow