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A Review of Contact Electrification at Diversified Interfaces and Related Applications on Triboelectric Nanogenerator 被引量:1
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作者 Jun Hu Mitsumasa Iwamoto Xiangyu Chen 《Nano-Micro Letters》 SCIE EI CAS CSCD 2024年第1期106-130,共25页
The triboelectric nanogenerator(TENG)can effectively collect energy based on contact electrification(CE)at diverse interfaces,including solid–solid,liquid–solid,liquid–liquid,gas–solid,and gas–liquid.This enables... The triboelectric nanogenerator(TENG)can effectively collect energy based on contact electrification(CE)at diverse interfaces,including solid–solid,liquid–solid,liquid–liquid,gas–solid,and gas–liquid.This enables energy harvesting from sources such as water,wind,and sound.In this review,we provide an overview of the coexistence of electron and ion transfer in the CE process.We elucidate the diverse dominant mechanisms observed at different interfaces and emphasize the interconnectedness and complementary nature of interface studies.The review also offers a comprehensive summary of the factors influencing charge transfer and the advancements in interfacial modification techniques.Additionally,we highlight the wide range of applications stemming from the distinctive characteristics of charge transfer at various interfaces.Finally,this review elucidates the future opportunities and challenges that interface CE may encounter.We anticipate that this review can offer valuable insights for future research on interface CE and facilitate the continued development and industrialization of TENG. 展开更多
关键词 contact electrification INTERFACES Triboelectric nanogenerators Diversified applications
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Changes of China’s Status in the Global System and Its Influencing Factors:A Multiple Contact Networks Perspective
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作者 LIU Jian LIU Jibin +2 位作者 YANG Qingshan CAI Sikai LIU Jie 《Chinese Geographical Science》 SCIE CSCD 2024年第2期265-279,共15页
Clarifying China’s position in the global system is an important logical basis for developing national diplomacy.Although much research has been done on China’s development status,most studies have been based on cou... Clarifying China’s position in the global system is an important logical basis for developing national diplomacy.Although much research has been done on China’s development status,most studies have been based on country comparisons or institutional en-vironment.In today’s networked era in which the global economy,trade,personnel,and information are closely connected,studies on China’s global position and its status changes and influencing factors in multiple contact networks are still insufficient.In this study,from the perspective of diverse global contact networks,we constructed economic,cultural,and political influence indices to explore the changes and influencing factors on China’s status in the global system from 2005 to 2018.The results show that during the study period,China’s global influence in the fields of economic ties,cultural exchanges,and political contacts increased significantly,but its influ-ence in the fields of cultural exchanges and political contacts lagged far economic ties.The pattern of China’s economic influence on various economies around the world has shown a transformation from an‘upright pyramid’to an‘inverted pyramid’structure.The proportion of these economies in low-influence zones has decreased from more than 60%in 2005 to less than 20%in 2018.China’s cultural and political influence on various economies around the world has increased significantly;however,for the former,the percentage of high-influence areas is still less than 20%,whereas for the latter the percentage of these economies in medium-and high-influence areas is still less than 50%.Analyses such as a scatter plot matrix show that geographical proximity,economic globalization,close cooperation with developing countries,and a proactive and peaceful foreign policy are important factors in improving China’s status in the diverse global network system. 展开更多
关键词 global system economic ties cultural exchanges political contacts multiple contact networks China’s status
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Igneous intrusion contact metamorphic system and its reservoir characteristics:A case study of Paleogene Shahejie Formation in Nanpu sag of Bohai Bay Basin,China
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作者 LI Wenke WU Xiaozhou +3 位作者 LI Yandong ZHANG Yan ZHANG Xin WANG Hai 《Petroleum Exploration and Development》 SCIE 2024年第2期320-336,共17页
Taking the Paleogene Shahejie Formation in Nanpu sag of Bohai Bay Basin as an example,this study comprehensively utilizes seismic,mud logging,well logging,physical property analysis and core thin section data to inves... Taking the Paleogene Shahejie Formation in Nanpu sag of Bohai Bay Basin as an example,this study comprehensively utilizes seismic,mud logging,well logging,physical property analysis and core thin section data to investigate the metamorphic reservoir formed by contact metamorphism after igneous rock intrusion.(1)A geological model of the igneous intrusion contact met amorphic system is proposed,which can be divided into five structural layers vertically:the intrusion,upper metamorphic aureole,lower metamorphic aureole,normal sedimentary layers on the roof and floor.(2)The intrusion is characterized by xenoliths indicating intrusive facies at the top,regular changes in rock texture and mineral crystallization from the center to the edge on a microscopic scale,and low-angle oblique penetrations of the intrusion through sedimentary strata on a macroscopic scale.The metamorphic aureole has characteristics such as sedimentary rocks as the host rock,typical palimpsest textures developed,various low-temperature thermal metamorphic minerals developed,and medium-low grade thermal metamorphic rocks as the lithology.(3)The reservoir in contact metamorphic aureole has two types of reservoir spaces:matrix pores and fractures.The matrix pores are secondary"intergranular pores"distributed around metamorphic minerals after thermal metamorphic transformation in metasandstones.The fractures are mainly structural fractures and intrusive compressive fractures in metamudstones.The reservoirs generally have three spatial distribution characteristics:layered,porphyritic and hydrocarbon impregnation along fracture.(4)The distribution of reservoirs in the metamorphic aureole is mainly controlled by the intensity of thermal baking.Furthermore,the distribution of favorable reservoirs is controlled by the coupling of favorable lithofacies and thermal contact metamorphism,intrusive compression and hydrothermal dissolution.The proposal and application of the geological model of the intrusion contact metamorphic system are expected to promote the discovery of exploration targets of contact metamorphic rock in Nanpu sag,and provide a reference for the study and exploration of deep contact metamorphic rock reservoirs in the Bohai Bay Basin. 展开更多
关键词 INTRUSION contact metamorphic aureole intrusion contact metamorphic system reservoir characteristics CENOZOIC Paleogene Shahejie Formation Nanpu sag Bohai Bay Basin
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Thermal-contact capacity of one-dimensional attractive Gaudin-Yang model
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作者 张小敏 程颂 陈洋洋 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第4期231-235,共5页
Tan's contact C is an important quantity measuring the two-body correlations at short distances in a dilute system.Here we make use of the technique of exactly solved models to study the thermal-contact capacity K... Tan's contact C is an important quantity measuring the two-body correlations at short distances in a dilute system.Here we make use of the technique of exactly solved models to study the thermal-contact capacity K_(T),i.e.,the derivative of C with respect to temperature in the attractive Gaudin-Yang model.It is found that K_(T) is useful in identifying the low temperature phase diagram,and using the obtained analytical expression of K_(T),we study its critical behavior and the scaling law.Especially,we show K_(T) versus temperature and thus the non-monotonic tendency of C in a tiny interval,for both spin-balanced and imbalanced phases.Such a phenomenon is merely observed in multi-component systems such as SU(2)Fermi gases and spinor bosons,indicating the crossover from the Tomonaga-Luttinger liquid to the spin-coherent liquid. 展开更多
关键词 Tan's contact Gaudin-Yang model Bethe ansatz
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Investigation of contact behavior on a model of the dual-mobility artificial hip joint for Asians in different inner liner thicknesses
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作者 Taufiq Hidayat Muhammad Imam Ammarullah +5 位作者 Rifky Ismail Eko Saputra M Danny Pratama Lamura Chethan K N Athanasius Priharyoto Bayuseno J Jamari 《World Journal of Orthopedics》 2024年第4期321-336,共16页
BACKGROUND The four components that make up the current dual-mobility artificial hip joint design are the femoral head,the inner liner,the outer liner as a metal cover to prevent wear,and the acetabular cup.The acetab... BACKGROUND The four components that make up the current dual-mobility artificial hip joint design are the femoral head,the inner liner,the outer liner as a metal cover to prevent wear,and the acetabular cup.The acetabular cup and the outer liner were constructed of 316L stainless steel.At the same time,the inner liner was made of ultra-high-molecular-weight polyethylene(UHMWPE).As this new dual-mobility artificial hip joint has not been researched extensively,more tribological research is needed to predict wear.The thickness of the inner liner is a significant component to consider when calculating the contact pressure.AIM To make use of finite element analysis to gain a better understanding of the contact behavior in various inner liner thicknesses on a new model of a dual-mobility artificial hip joint,with the ultimate objective of determining the inner liner thickness that was most suitable for this particular type of dual-mobility artificial hip joint.METHODS In this study,the size of the femoral head was compared between two diameters(28 mm and 36 mm)and eight inner liner thicknesses ranging from 5 mm to 12 mm.Using the finite element method,the contact parameters,including the maximum contact pressure and contact area,have been evaluated in light of the Hertzian contact theory.The simulation was performed statically with dissipated energy and asymmetric behavior.The types of interaction were surface-to-surface contact and normal contact behavior.RESULTS The maximum contact pressures in the inner liner(UHMWPE)at a head diameter of 28 mm and 36 mm are between 3.7-13.5 MPa and 2.7-10.4 MPa,respectively.The maximum von Mises of the inner liner,outer liner,and acetabular cup are 2.4–11.4 MPa,15.7–44.3 MPa,and 3.7–12.6 MPa,respectively,for 28 mm head.Then the maximum von Mises stresses of the 36 mm head are 1.9-8.9 MPa for the inner liner,9.9-32.8 MPa for the outer liner,and 2.6-9.9 MPa for the acetabular cup.A head with a diameter of 28 mm should have an inner liner with a thickness of 12 mm.Whereas the head diameter was 36 mm,an inner liner thickness of 8 mm was suitable.CONCLUSION The contact pressures and von Mises stresses generated during this research can potentially be exploited in estimating the wear of dual-mobility artificial hip joints in general.Contact pressure and von Mises stress reduce with an increasing head diameter and inner liner’s thickness.Present findings would become one of the references for orthopedic surgery for choosing suitable bearing geometric parameter of hip implant. 展开更多
关键词 contact behavior contact pressure Finite element analysis Dual-mobility Artificial hip joint
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Lubrication performance of graphene in the sliding electrical contact interface
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作者 Lv WANG Qian TANG +7 位作者 Tao LIANG Chenxu LIU Deen SUN Shu WANG Jingchuan LI Sam ZHANG Yonggang MENG Yuehua HUANG 《Friction》 SCIE EI CAS CSCD 2024年第12期2760-2773,共14页
Electrical contact materials are increasingly widely used,but the existing electric contact lubricants still have lots of room for improvement,such as anti-wear performance and lubrication life.Due to the excellent el... Electrical contact materials are increasingly widely used,but the existing electric contact lubricants still have lots of room for improvement,such as anti-wear performance and lubrication life.Due to the excellent electrical and lubrication properties,graphene shows great potential in lubricating the sliding electrical contact interface,but there is a lack of relevant research.Some researchers have studied the lubrication performance of graphene between the gold-coated/TiN-coated friction pair at an ultra-low current.However,the lubrication performance of graphene on more widely used electrical contact materials such as copper and its alloys under larger and more commonly used current or voltage conditions has not been reported.In this paper,we study the lubrication performance of graphene in the copper and its alloys sliding electrical contact interface under usual parameters,which is explored through four aspects:different substrates-copper and brass,different test methods-constant voltage and constant current,different normal loads and durability test.The experiments demonstrate that graphene can significantly reduce the friction and wear on brass and copper under the above test methods and parameters,with low contact resistance at the same time.Our work is expected to provide a new lubricant for electrical contact materials and contribute to enriching the tribological theory of graphene. 展开更多
关键词 GRAPHENE sliding electrical contact COPPER FRICTION-REDUCING ANTI-WEAR low-contact resistance
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In situ non-destructive measurement of Josephson junction resistance using fritting contact technique
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作者 Lei Du Hao-Ran Tao +7 位作者 Liang-Liang Guo Hai-Feng Zhang Yong Chen Xin Tian Chi Zhang Zhi-Long Jia Peng Duan Guo-Ping Guo 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第11期57-61,共5页
Conventional four-probe methods for measuring the resistance of Josephson junctions can damage superconducting thin films,making them unsuitable for frequency measurements of superconducting qubits.In this study,we pr... Conventional four-probe methods for measuring the resistance of Josephson junctions can damage superconducting thin films,making them unsuitable for frequency measurements of superconducting qubits.In this study,we present a custom probe station measurement system that employs the fritting contact technique to achieve in situ,non-destructive measurements of Josephson junction resistance.Our experimental results demonstrate that this method allows for accurate prediction of qubit frequency with an error margin of 17.2 MHz.Moreover,the fritting contact technique does not significantly affect qubit coherence time or the integrity of the superconducting film,confirming its non-destructive nature.This innovative approach provides a dependable foundation for frequency tuning and addressing frequency collision issues,thus supporting the advancement and practical deployment of superconducting quantum computing. 展开更多
关键词 NON-DESTRUCTIVE fritting contact qubit frequency Josephson junction resistance
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Effect of surface modification on the radiation stability of diamond ohmic contacts
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作者 牟恋希 赵上熳 +7 位作者 王鹏 原晓芦 刘金龙 朱志甫 陈良贤 魏俊俊 欧阳晓平 李成明 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第2期444-448,共5页
The ohmic contact interface between diamond and metal is essential for the application of diamond detectors.Surface modification can significantly affect the contact performance and eliminate the interface polarizatio... The ohmic contact interface between diamond and metal is essential for the application of diamond detectors.Surface modification can significantly affect the contact performance and eliminate the interface polarization effect.However,the radiation stability of a diamond detector is also sensitive to surface modification.In this work,the influence of surface modification technology on a diamond ohmic contact under high-energy radiation was investigated.Before radiation,the specific contact resistivities(ρc)between Ti/Pt/Au-hydrogen-terminated diamond(H-diamond)and Ti/Pt/Au-oxygenterminated diamond(O-diamond)were 2.0×10^(-4)W·cm^(2) and 4.3×10^(-3)Wcm^(2),respectively.After 10 MeV electron radiation,the ρc of Ti/Pt/Au H-diamond and Ti/Pt/Au O-diamond were 5.3×10^(-3)W·cm^(2)and 9.1×10^(-3)W·cm^(2),respectively.The rates of change of ρc of H-diamond and O-diamond after radiation were 2550%and 112%,respectively.The electron radiation promotes bond reconstruction of the diamond surface,resulting in an increase in ρc. 展开更多
关键词 single crystal diamond ohmic contact surface modification electron radiation
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Supposition of graphene stacks to estimate the contact resistance and conductivity of nanocomposites
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作者 Y.ZARE M.T.MUNIR +1 位作者 G.J.WENG K.Y.RHEE 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第4期663-676,共14页
In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equ... In this study,the effects of stacked nanosheets and the surrounding interphase zone on the resistance of the contact region between nanosheets and the tunneling conductivity of samples are evaluated with developed equations superior to those previously reported.The contact resistance and nanocomposite conductivity are modeled by several influencing factors,including stack properties,interphase depth,tunneling size,and contact diameter.The developed model's accuracy is verified through numerous experimental measurements.To further validate the models and establish correlations between parameters,the effects of all the variables on contact resistance and nanocomposite conductivity are analyzed.Notably,the contact resistance is primarily dependent on the polymer tunnel resistivity,contact area,and tunneling size.The dimensions of the graphene nanosheets significantly influence the conductivity,which ranges from 0 S/m to90 S/m.An increased number of nanosheets in stacks and a larger gap between them enhance the nanocomposite's conductivity.Furthermore,the thicker interphase and smaller tunneling size can lead to higher sample conductivity due to their optimistic effects on the percolation threshold and network efficacy. 展开更多
关键词 graphene polymer composite stacked nanosheet tunneling conductivity contact resistance INTERPHASE
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Heterogeneities of grain boundary contact for simulation of laboratoryscale mechanical behavior of granitic rocks
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作者 Xiongyu Hu Marte Gutierrez Zhiwei Yan 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第7期2629-2644,共16页
From a practical point of view,grain structure heterogeneities are key parameters that control the rock response and still remains a challenge to incorporate in a quantitative manner.One of the less discussed topics i... From a practical point of view,grain structure heterogeneities are key parameters that control the rock response and still remains a challenge to incorporate in a quantitative manner.One of the less discussed topics in the context of the grain-based model(GBM)in the particle flow code(PFC)is the contact heterogeneities and the appropriate contact model to mimic the grain boundary behavior.Generally,the smooth joint(SJ)model and linear parallel bond(LPB)model are used to simulate the grain boundary behavior.However,the literature does not document the suitability of different models for specific problems.Another challenge in implementing GBM in PFC is that only a single bonding parameter is used at the grain boundaries.The aim of this study is to investigate the responses of a laboratory-scale specimen with SJ and LPB models,considering grain boundary heterogeneous and homogeneous contact parameters.Uniaxial and biaxial compression tests are performed to calibrate the response of Creighton granite.The stressestrain curves,volumetric dilation,inter-crack(crack in the grain boundary),and intra-crack(crack within the grain)development,and failure patterns associated with different contact models are examined.It was found that both the SJ and LPB models can reproduce the pre-peak behavior observed for a granitic rock type.However,the LPB model is unable to reproduce the post-peak behavior.Due to the large interlocking effect originating from the balls in contact and the ball size in the LPB model,local dilation is induced at the grain boundaries.This overestimates the volumetric dilation and residual shear strength.The LPB model tends to result in discontinuous inter-cracks and stress localization in the rock specimen,resulting in fine fragments at the rock surface during failure. 展开更多
关键词 Grain boundary contact Smooth joint(SJ)model Linear parallel bond(LPB)model contact heterogeneities Particle flow code(PFC) Granitic rock
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Topographic variation and fluid flow characteristics in rough contact interface
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作者 Jiawei JI Wei SUN +5 位作者 Yu DU Yongqing ZHU Yuhang GUO Xiaojun LIU Yunlong JIAO Kun LIU 《Friction》 SCIE EI CAS CSCD 2024年第12期2774-2790,共17页
Understanding flow characteristics of fluid near rough contact is important for the design of fluid-based lubrication and basic of tribology physics.In this study,the spreading and seepage processes of anhydrous ethan... Understanding flow characteristics of fluid near rough contact is important for the design of fluid-based lubrication and basic of tribology physics.In this study,the spreading and seepage processes of anhydrous ethanol in the interface between glass and rough PDMS are observed by a homemade optical in-situ tester.Digital image processing technology and numerical simulation software are adapted to identify and extract the topological properties of interface and thin fluid flow characteristics.Particular attention is paid to the dynamic evolution of the contact interface morphology under different stresses,the distribution of microchannels in the interface,the spreading characteristics of the fluid in contact interface,as well as the mechanical driving mechanism.Original surface morphology and the contact stress have a significant impact on the interface topography and the distribution of interfacial microchannels,which shows that the feature lengths of the microchannels,the spreading area and the spreading rate of the fluid are inversely proportional to the load.And the flow path of the fluid in the interface is mainly divided into three stages:along the wall of the island,generating liquid bridges,and moving from the tip side to the root side in the wedge-shaped channel.The main mechanical mechanism of liquid flow in the interface is the equilibrium between the capillary force that drives the liquid spreading and viscous resistance of solid wall to liquid.In addition,the phenomenon of“trapped air”occurs during the flow process due to the irregular characteristics of the microchannel.This study lays a certain theoretical foundation for the research of microscopic flow behavior of the liquid in the rough contact interface,the friction and lubrication of the mechanical system,and the sealing mechanism. 展开更多
关键词 rough contact interface fluid flow topography evolution MICROCHANNEL in-situ observation
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A hybrid contact approach for modeling soil-structure interaction using the material point method
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作者 Qinyang Sang Yonglin Xiong +3 位作者 Rongyue Zheng Xiaohua Bao Guanlin Ye Feng Zhang 《Journal of Rock Mechanics and Geotechnical Engineering》 SCIE CSCD 2024年第5期1864-1882,共19页
The grid-based multi-velocity field technique has become increasingly popular for simulating the Material Point Method(MPM)in contact problems.However,this traditional technique has some shortcomings,such as(1)early c... The grid-based multi-velocity field technique has become increasingly popular for simulating the Material Point Method(MPM)in contact problems.However,this traditional technique has some shortcomings,such as(1)early contact and contact penetration can occur when the contact conditions are unsuitable,and(2)the method is not available for contact problems involving rigid-nonrigid materials,which can cause numerical instability.This study presents a new hybrid contact approach for the MPM to address these limitations to simulate the soil and structure interactions.The approach combines the advantages of point-point and point-segment contacts to implement contact detection,satisfying the impenetrability condition and smoothing the corner contact problem.The proposed approach is first validated through a disk test on an inclined slope.Then,several typical cases,such as granular collapse,bearing capacity,and deformation of a flexible retaining wall,are simulated to demonstrate the robustness of the proposed approach compared with FEM or analytical solutions.Finally,the proposed method is used to simulate the impact of sand flow on a deformable structure.The results show that the proposed contact approach can well describe the phenomenon of soil-structure interaction problems. 展开更多
关键词 Material point method Soil-structure interaction Numerical simulation contact algorithm
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Application of Isogeometric Analysis Method in Three-Dimensional Gear Contact Analysis
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作者 Long Chen Yan Yu +2 位作者 Yanpeng Shang Zhonghou Wang Jing Zhang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第4期817-846,共30页
Gears are pivotal in mechanical drives,and gear contact analysis is a typically difficult problem to solve.Emerging isogeometric analysis(IGA)methods have developed new ideas to solve this problem.In this paper,a thre... Gears are pivotal in mechanical drives,and gear contact analysis is a typically difficult problem to solve.Emerging isogeometric analysis(IGA)methods have developed new ideas to solve this problem.In this paper,a threedimensional body parametric gear model of IGA is established,and a theoretical formula is derived to realize single-tooth contact analysis.Results were benchmarked against those obtained from commercial software utilizing the finite element analysis(FEA)method to validate the accuracy of our approach.Our findings indicate that the IGA-based contact algorithmsuccessfullymet theHertz contact test.When juxtaposed with the FEA approach,the IGAmethod demonstrated fewer node degrees of freedomand reduced computational units,all whilemaintaining comparable accuracy.Notably,the IGA method appeared to exhibit consistency in analysis accuracy irrespective of computational unit density,and also significantlymitigated non-physical oscillations in contact stress across the tooth width.This underscores the prowess of IGA in contact analysis.In conclusion,IGA emerges as a potent tool for addressing contact analysis challenges and holds significant promise for 3D gear modeling,simulation,and optimization of various mechanical components. 展开更多
关键词 contact analysis involute gear isogeometric analysis finite element analysis
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Advancing high-speed train gearbox durability:enhanced bearing load and contact stress through transition from helical to herringbone gears
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作者 Hao Wu Jing Wei +2 位作者 Pingbo Wu Fansong Li Yayun Qi 《Railway Engineering Science》 EI 2024年第4期461-479,共19页
High-speed trains typically utilize helical gear transmissions,which significantly impact the bearing load capacity and fatigue service performance of the gearbox bearings.This paper focuses on the gearbox bearings,es... High-speed trains typically utilize helical gear transmissions,which significantly impact the bearing load capacity and fatigue service performance of the gearbox bearings.This paper focuses on the gearbox bearings,establishing dynamic models for both helical gear and herringbone gear transmissions in high-speed trains.The modeling particularly emphasizes the precision of the bearings at the gearbox's pinion and gear wheels.Using this model,a comparative analysis is conducted on the bearing loads and contact stresses of the gearbox bearings under uniform-speed operation between the two gear transmissions.The findings reveal that the helical gear transmission generates axial forces leading to severe load imbalance on the bearings at both sides of the large gear,and this imbalance intensifies with the increase in train speed.Consequently,this results in a significant increase in contact stress on the bearings on one side.The adoption of herringbone gear transmission effectively suppresses axial forces,resolving the load imbalance issue and substantially reducing the contact stress on the originally biased side of the bearings.The study demonstrates that employing herringbone gear transmission can significantly enhance the service performance of high-speed train gearbox bearings,thereby extending their service life. 展开更多
关键词 High-speed train Herringbone gear Helical gear Gearbox bearings contact stress
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Analytical modeling and approaches of multihelix cables incorporating with interwire mutual contacts
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作者 Zhichao ZHANG Xingzhe WANG 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第9期1633-1654,共22页
This study aims to develop an analytical model based on the curve beam theory to capture the mechanical response of a multihelix cable considering the internal contact displacements.Accordingly,a double-helix cable su... This study aims to develop an analytical model based on the curve beam theory to capture the mechanical response of a multihelix cable considering the internal contact displacements.Accordingly,a double-helix cable subjected to axial tension and torsion is analyzed,and both the line and point contacts between the neighboring wires and strands are considered via an equivalent homogenized approach.Then,the proposed theoretical model is extended to a hierarchical multihelix cable with mutual contact displacements by constructing a recursive relationship between the high-and low-level multihelix structures.The global tensile stiffness and torsional stiffness of the double-helix cable are successfully evaluated.The results are validated by a finite element(FE)model,and are found to be consistent with the findings of previous studies.It is shown that the contact deformations in multihelix cables significantly affect their equivalent mechanical stiffness,and the contact displacements are remarkably enhanced as the helix angles increase.This study provides insights into the interwire/interstrand mutual contact effects on global and local responses. 展开更多
关键词 wordshierarchical multihelix cable mutual contact effect mechanical response effective stiffness
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Analysis model for damage of reinforced bars in RC beams under contact explosion
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作者 Chaozhi Yang Zhengxiang Huang +2 位作者 Xin Jia Wei Shang Jian Zhang 《Defence Technology(防务技术)》 SCIE EI CAS CSCD 2024年第11期104-118,共15页
The load-bearing capacity of reinforced concrete(RC) beams primarily relies on internal reinforced bars.However, limited research has been conducted on the dynamic response of these bars. To address this gap, this stu... The load-bearing capacity of reinforced concrete(RC) beams primarily relies on internal reinforced bars.However, limited research has been conducted on the dynamic response of these bars. To address this gap, this study has established an analytical model using dimensional analysis for calculating the deformation of reinforced bars within RC beams subjected to contact explosion. Comparison with experimental data reveals that the model has a relative error of 5.22%, effectively reflecting the deformation of reinforced bars. Additionally, based on this model, the study found that while concrete does influence the deformation of reinforced bars, this influence can be disregarded in comparison to the material properties of the bars themselves. The findings of this study have implications for calculating the residual load-bearing capacity of damaged RC beams, evaluating the extent of damage to RC beams after blast loading, and providing guidance for the blast-resistant design of RC structures. 展开更多
关键词 Reinforced concrete beam contact explosion Reinforced bar Damage analysis Residual load-bearing capacity
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Modification of contact lenses via metal-organic frameworks for glaucoma treatment
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作者 Alexey V.Yaremenko Roman O.Melikov +19 位作者 Nadezhda A.Pechnikova Iaroslav B.Belyaev Alina Ringaci Tamara V.Yaremenko Aziz B.Mirkasymov Alexandr A.Tamgin Vladislav I.Rodionov Sofya M.Dolotova Grigory A.Plisko Evgeny D.Semivelichenko Anna S.Rogova Albert R.Muslimov Arina S.Ivkina Dmitry Yu.Ivkin Valery P.Erichev Sergey M.Deyev Sergey E.Avetisov Yongjiang Li Hai-Jun Liu Ivan V.Zelepukin 《Aggregate》 EI CAS 2024年第5期358-370,共13页
The prevention of blindness from glaucoma requires multiple treatments to lower intraocular pressure.Here,human contact lenses are modified with highly porous metal-organic frameworks with sustained release of brimonid... The prevention of blindness from glaucoma requires multiple treatments to lower intraocular pressure.Here,human contact lenses are modified with highly porous metal-organic frameworks with sustained release of brimonidine for prolonged glaucoma treatment.Various metal-organic frameworks were screened for their attachment to lenses,loading with brimonidine,and drug-release properties.Opti-mized therapeutic ocular lenses conjugated with MIL-101(Cr)frameworks maintain optical transparency and power.Coating of lenses with MIL-101(Cr)nanoparticles reduced brimonidine washout with tears and ensured a gradual and localized release of the drug into the eyeball through the cornea.The hybrid lenses provided a 4.5-fold better decrease in eye pressure,compared by area under the curve(AUC)value to a commercially available brimonidine tartrate solution.Therapeutic lenses did not induce any notable eye irritation or corneal damage in vivo.The newly devel-oped hybrid lenses are expected to provide a robust platform for the therapy and prevention of various ocular diseases. 展开更多
关键词 BRIMONIDINE contact lenses drug delivery GLAUCOMA intraocular pressure metal-organic frameworks NANOPARTICLES
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Contact Stress Reliability Analysis Model for Cylindrical Gear with Circular Arc Tooth Trace Based on an Improved Metamodel
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作者 Qi Zhang Zhixin Chen +5 位作者 Yang Wu Guoqi Xiang Guang Wen Xuegang Zhang Yongchun Xie Guangchun Yang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2024年第7期593-619,共27页
Although there is currently no unified standard theoretical formula for calculating the contact stress of cylindrical gears with a circular arc tooth trace(referred to as CATT gear),a mathematical model for determinin... Although there is currently no unified standard theoretical formula for calculating the contact stress of cylindrical gears with a circular arc tooth trace(referred to as CATT gear),a mathematical model for determining the contact stress of CATT gear is essential for studying how parameters affect its contact stress and building the contact stress limit state equation for contact stress reliability analysis.In this study,a mathematical relationship between design parameters and contact stress is formulated using the KrigingMetamodel.To enhance the model’s accuracy,we propose a new hybrid algorithm that merges the genetic algorithm with the Quantum Particle Swarm optimization algorithm,leveraging the strengths of each.Additionally,the“parental inheritance+self-learning”optimization model is used to fine-tune the KrigingMetamodel’s parameters.Following this,amathematicalmodel for calculating the contact stress of Variable Hyperbolic Circular-Arc-Tooth-Trace(VH-CATT)gears using the optimized Kriging model was developed.We then examined how different gear parameters affect the VH-CATT gears’contact stress.Our simulation results show:(1)Improvements in R2,RMSE,and RMAE.R2 rose from0.9852 to 0.9974(a 1.22%increase),nearing 1,suggesting the optimized Kriging Metamodel’s global error is minimized.Meanwhile,RMSE dropped from3.9210 to 1.6492,a decline of 57.94%.The global error of the GA-IQPSO-Kriging algorithm was also reduced,with RMAE decreasing by 58.69%from 0.1823 to 0.0753,showing the algorithm’s enhanced precision.In a comparison of ten experimental groups selected randomly,the GA-IQPSO-Kriging and FEM-based contact analysis methods were used to measure contact stress.Results revealed a maximum error of 12.11667 MPA,which represents 2.85%of the real value.(2)Several factors,including the pressure angle,tooth width,modulus,and tooth line radius,are inversely related to contact stress.The descending order of their impact on the contact stress is:tooth line radius>modulus>pressure angle>tooth width.(3)Complex interactions are noted among various parameters.Specifically,when the tooth line radius interacts with parameters such as pressure angle,tooth width,and modulus,the resulting stress contour is nonlinear,showcasing amultifaceted contour plane.However,when tooth width,modulus,and pressure angle interact,the stress contour is nearly linear,and the contour plane is simpler,indicating a weaker coupling among these factors. 展开更多
关键词 CATT gear contact stress finite element method METAMODEL hybrid algorithm influencing factors
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Highly divergent sympatric lineages of Leptotila verreauxi(Aves:Columbidae)suggest a secondary contact area in the Isthmus of Tehuantepec,Mexico
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作者 Orlando J.Espinosa-Chávez Adolfo G.Navarro-Sigüenza +1 位作者 Hernando Rodríguez-Correa Luis A.Sánchez-González 《Avian Research》 SCIE CSCD 2024年第1期12-21,共10页
Due to a complex geological and biotic history,the Isthmus of Tehuantepec(IT),has been long recognized as a driver for the evolutionary divergence of numerous lowland and highland taxa.Widely distributed in the lowlan... Due to a complex geological and biotic history,the Isthmus of Tehuantepec(IT),has been long recognized as a driver for the evolutionary divergence of numerous lowland and highland taxa.Widely distributed in the lowlands of the American continent,the White-Tipped Dove(Leptotila verreauxi)is a polytypic species with 13 recognized subspecies.Four of these have been recorded in Mexico,and the distribution of three abuts at the IT,suggesting a contact zone.To estimate phylogenetic patterns,divergence times and genetic differentiation,we examined two mt DNA(ND2 and COI)and one n DNA(β-fibint 7)markers.We also used correlative ecological niche models(ENM)to assess whether ecological differences across the IT may have acted as a biogeographical boundary.We estimated paleodistributions during the Middle Holocene,Last Glacial Maximum and Last Interglacial,to evaluate the influence of climate changes on the distribution and demographic changes.Our results showed genetically distinct lineages that diverged approximately 2.5 million years ago.Climatic and ecological factors may have played a dual role in promoting differentiation,but also in the formation of a secondary contact zone in the southern IT.Our ecological niche comparisons indicated that the ecological niche of sympatric lineages at the IT are not identical,suggesting niches divergence;in addition,environmental niche models across the region indicated no abrupt biogeographic barriers,but the presence of regions with low suitability.These results suggest that genetic differentiation originated by a vicariant event probably related to environmental factors,favored the evolution of different ecological niches.Also,the absence of a biogeographic barrier but the presence of less suitable areas in the contact regions,suggest that secondary contact zones may be also maintained by climatic factors for the eastern group,but also by biotic interactions for the western group. 展开更多
关键词 Biogeographical boundary Humid and dry forests Isthmus of Tehuantepec PHYLOGEOGRAPHY Secondary contact
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Frictional contact analysis of a rigid solid with periodic surface sliding on the thermoelectric material
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作者 Yali ZHANG Yueting ZHOU Shenghu DING 《Applied Mathematics and Mechanics(English Edition)》 SCIE EI CSCD 2024年第1期179-196,共18页
Understanding and characterizing rough contact and wavy surfaces are essential for developing effective strategies to mitigate wear,optimize lubrication,and enhance the overall performance and durability of mechanical... Understanding and characterizing rough contact and wavy surfaces are essential for developing effective strategies to mitigate wear,optimize lubrication,and enhance the overall performance and durability of mechanical systems.The sliding friction contact problem between a thermoelectric(TE)half-plane and a rigid solid with a periodic wavy surface is the focus of this investigation.To simplify the problem,we utilize mixed boundary conditions,leading to a set of singular integral equations(SIEs)with the Hilbert kernels.The analytical solutions for the energy flux and electric current density are obtained by the variable transform method in the context of the electric and temperature field.The contact problem for the elastic field is transformed into the second-kind SIE and solved by the Jacobi polynomials.Notably,the smoothness of the wavy contact surface ensures that there are no singularities in the surface contact stress,and ensures that it remains free at the contact edge.Based on the plane strain theory of elasticity,the analysis primarily examines the correlation between the applied load and the effective contact area.The distribution of the normal stress on the surface with or without TE loads is discussed in detail for various friction coefficients.Furthermore,the obtained results indicate that the in-plane stress decreases behind the trailing edge,while it increases ahead of the trailing edge when subjected to TE loads. 展开更多
关键词 wavy surface periodic contact thermoelectric(TE)material Hilbert integral kernel
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