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Mechanism Study on the Effect of Retarder on Polyurethane Setting Time Based on Molecular Simulation

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Journal of Wuhan University of Technology(Materials Science) 2025年第1期40卷 224-231页

作者： WU Yuxuan XU Wenyuan YU Tianlai JI Yongcheng school of civil Engineering Northeast Forestry UniversityHarbin 150040China

This study identified castor oil and phosphate ester as effective retarders through setting time,tensile,and flexural tests,and determined their optimal *** mechanism by which phosphate ester affects the setting time of polyurethane was further investigated using molecular dynamics *** transform infrared spectroscopy was also employed to systematically study the physical and chemical interactions between phosphate esters and polyurethane *** results demonstrate that a 1%concentration of phosphate ester provides the most effective retarding effect with minimal impact on the strength of *** phosphate ester is added to the B component of the two-component polyurethane system,its interaction energy with component A decreases,as do the diffusion coefficient and aggregation degree of component B on the surface of component *** reduction in interaction slows the setting ***,the addition of phosphate ester to polyurethane leads to the disappearance or weakening of functional groups,indicating competitive interactions within the phosphate ester components that inhibit the reaction rate.

关键词： polyurethane retarder setting time molecular dynamics diffusion coefficient

Fatigue Properties of RPC under Cyclic Loads of Single-stage and Multi-level Amplitude

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Journal of Wuhan University of Technology(Materials Science) 2010年第1期25卷 167-173页

作者：安明喆 school of civil engineeringss Beijing Jiaotong University

Fatigue properties of Reactive Powder Concrete （RPC） under axial compression of single-stage and multi-level amplitude in cycles were studied. The tests reveal the fatigue life, the strain and residual life of the RPC samples. Through the analysis of the test results under cyclic loads of single amplitude, the S-N curve of RPC and the evolution rule of macro-damage of RPC were presented, which can be divided into latency stage, stable development stage and instability development stage according to the evolution pattern of the fatigue crack. Accordingly, the development of longitudinal deformation presents the similar three-stage-model, and the proportion of each stage is 15%, 75%, and 10%. According to test results, the fatigue strength reduction factor is 0.564. We brought forward an empirical formula to predict the life of RPC via total longitudinal strain and got the evolving rule for the residual strength of the RPC. The analysis of the test results under cyclic loads of multi-level amplitude shows that the strain under this loading pattern experiences three stages. The characteristic value for the residual strain was obtained. The irreversible damage and non-linear evolution of RPC was described by the development of the residual plastic strain.

关键词： Reactive Powder Concrete (RPC) single-stage amplitude multi-level amplitude fatigue

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Distributed fiber optic sensing system for vibration monitoring of 3D printed bridges

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Optoelectronics Letters 2025年第1期21卷 28-34页

作者： ZHAO Shuai ZHOU Ran LUO Mingming LIU Jianfei LIU Xiongfei ZHOU Tao school of Electronic Information Engineering Hebei University of Technology Tianjin Key Laboratory of Electronic Materials and Devices school of civil Engineering and Transportation Hebei University of Technology Tianjin Jinhang Institute of Technical Physics

The fiber optic sensing technology provides data support in structural health monitoring of the macro facilities, including design, construction, and maintenance of bridges, tunnels, ports and other infrastructures. In this paper, a distributed vibration sensing system is proved to be responsive to a single touch over a 1.8-m-long equivalent fiber segment, covering a vibration frequency from 5 Hz to 25 kHz. The sensing fiber was arranged as an S type layout on the bridge to recognize the standing state, windblown disturbance, and walking vibration. Moreover, the knocking and climbing events are recognized fiber laying spinning lines and hanging on the fences, respectively. The demonstration shows an accurate positioning and sensitive vibration monitoring applied on the automated three-dimensional(3D) printed bridge, which is applicable to all kinds of 3D printed facilities as intelligent sensory neuro-networks.

关键词： Spinning (fibers)

Recent progress in constructing fluorinated solid-electrolyte interphases for stable lithium metal anodes

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 270-291页

作者： Di Zhang Pengfei Lv Wei Qin Xin He Yuanhua He civil Aircraft Fire Science and Safety Engineering Key Laboratory of Sichuan Province College of Civil Aviation Safety EngineeringCivil Aviation Flight University of ChinaGuanghan 618307China school of Chemical Engineering Sichuan UniversityChengdu 610065China

Lithium metal batteries(LMBs)are emerging as a promising energy storage solution owing to their high energy density and specific ***,the non-uniform plating of lithium and the potential rupture of the solid-electrolyte interphase(SEI)during extended cycling use may result in dendrite growth,which can penetrate the separator and pose significant short-circuit *** a stable SEI is essential for the long-term operation of the ***-rich SEI has garnered significant attention for its ability to effectively passivate electrodes,regulate lithium deposition,and inhibit electrolyte *** the structural components and preparation methods of existing fluorinated SEI is crucial for optimizing lithium metal anode *** paper reviews the research on optimizing LiF passivation interfaces to protect lithium metal *** focuses on four types of compositions in fluorinated SEI that work synergistically to enhance SEI *** instance,combining compounds with LiF can further enhance the mechanical strength and ionic conductivity of the *** metals with LiF significantly improves electrochemical performance at the SEI/anode interface,with a necessary focus on reducing electron tunneling ***,incorporating polymers with LiF offers balanced improvements in interfacial toughness and ionic conductivity,though maintaining structural stability over long cycles remains a critical area for future *** alloys combined with LiF increase surface energy and lithium affinity,challenges such as dendrite growth and volume expansion *** summary,this paper emphasizes the crucial role of interfacial structures in LMBs and offers comprehensive guidance for future design and development efforts in battery technology.

关键词： LiF lithium metal anodes solid-electrolyte interphase interface cycling stability

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Bending Stiffness of Concrete-Filled Steel Tube and Its Influence on Concrete Placement Timing of Composite Beam-String Structure

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Structural Durability & Health Monitoring 2025年第1期19卷 55-75页

作者： Zhenyu Zhang Quan Jin Haitao Zhang Zhao Liu Yuyang Wu Longfei Zhang Renzhang Yan CCCC Third Highway Engineering Co. Ltd.Beijing101300China school of civil Engineering Chongqing Jiaotong UniversityChongqing400074China

When the upper chord beam of the beam-string structure(BSS)is made of concrete-filled steel tube(CFST),its overall stiffness will change greatly with the construction of concrete placement,which will have an impact on the design of the tensioning plans and selection of control measures for the *** order to accurately obtain the bending stiffness of CFST beam and clarify its impact on the mechanical properties of composite BSS during construction,the influence of some factors such as height-width ratio,wall thickness of steel tube,elasticity modulus of concrete,and friction coefficient on the bending stiffness are analyzed parametrically by the numerical simulation technology based on an actual *** calculation formula of the equivalent bending stiffness of CFST is also established through mathematical statistical ***,the equivalent bending stiffness is introduced into the construction and use stages of the composite BSS,respectively,and the mechanical properties such as prestress-tensioning control value,structural deformation,and internal force of key members are comparatively analyzed when adopting two different construction ***,the optimal construction plan of concrete placement first and then prestress-tensioning is proposed.

关键词： Concrete panels freeze-thaw damage compression-shear crack tension-shear crack

Structural Modal Parameter Recognition and Related Damage Identification Methods under Environmental Excitations: A Review

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Structural Durability & Health Monitoring 2025年第1期19卷 25-54页

作者： Chao Zhang Shang-Xi Lai Hua-Ping Wang school of civil Engineering and Mechanics Lanzhou UniversityLanzhou730000China Key Laboratory of Special Functional Materials and Structural Design Ministry of EducationLanzhou UniversityLanzhou730000China

Modal parameters can accurately characterize the structural dynamic properties and assess the physical state of the ***,it is particularly signiﬁcant to identify the structural modal parameters according to the monitoring data information in the structural health monitoring(SHM)system,so as to provide a scientiﬁc basis for structural damage identiﬁcation and dynamic model modiﬁ*** view of this,this paper reviews methods for identifying structural modal parameters under environmental excitation and brieﬂy describes how to identify structural damages based on the derived modal *** paper primarily introduces data-driven modal parameter recognition methods(e.g.,time-domain,frequency-domain,and time-frequency-domain methods,etc.),brieﬂy describes damage identiﬁcation methods based on the variations of modal parameters(e.g.,natural frequency,modal shapes,and curvature modal shapes,etc.)and modal validation methods(e.g.,Stability Diagram and Modal Assurance Criterion,etc.).The current status of the application of artiﬁcial intelligence(AI)methods in the direction of modal parameter recognition and damage identiﬁcation is further *** on the pre-vious analysis,the main development trends of structural modal parameter recognition and damage identiﬁcation methods are given to provide scientiﬁc references for the optimized design and functional upgrading of SHM systems.

关键词： Structural health monitoring data information modal parameters damage identiﬁcation AI method

Rock fracture mechanism of buffer blasting with cushion layer at the borehole bottom

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 325-334页

作者： Xinguang Zhu Chenxi Ding Zhe Sui Hong Su Xu Guo school of civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China Key Laboratory for Mechanics in Fluid Solid Coupling Systems Institute of MechanicsChinese Academy of SciencesBeijing 100190China school of Mechanics and civil Engineering China University of Mining and Technology(Beijing)Beijing 100083China school of Chemical and Blasting Engineering Anhui University of Science and TechnologyHuainan 232001China

This study primarily investigates the rock fracture mechanism of bottom cushion layer blasting and explores the effects of the bottom cushion layer on rock *** involves analyses of the evolution patterns of blasting stress,characteristics of crack distribution,and rock fracture features in the ***,blasting model experiments were carried out using the dynamic caustics principle to investigate the influence of bottom cushion layers and initiation methods on the integrity of the bottom rock *** experimental results indicate that the combined use of bottom cushion layers and inverse initiation effectively protects the integrity of the bottom rock ***,the process of stress wave propagation and dynamic crack propagation in rocks was simulated using the continuum-discontinuum element method(CDEM)and the Landau explosion source model,with varying thicknesses of bottom cushion *** numerical simulation results indicate that with increasing cushion thickness,the absorption of energy generated by the explosion becomes more pronounced,resulting in fewer cracks in the bottom rock *** illustrates the positive role of the cushion layer in protecting the integrity of the bottom rock mass.

关键词： bottom cushion layer blasting crack propagation continuum-discontinuum element method dynamic stress intensity factor

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Joint Estimation of SOH and RUL for Lithium-Ion Batteries Based on Improved Twin Support Vector Machineh

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Energy Engineering 2025年第1期122卷 243-264页

作者： Liyao Yang HongyanMa Yingda Zhang Wei He school of Electrical and Information Engineering Beijing University of Civil Engineering and ArchitectureBeijing100044China Institute of Distributed Energy Storage Safety Big Data Beijing100044China Beijing Key Laboratory of Intelligent Processing for Building Big Data Beijing100044China

Accurately estimating the State of Health(SOH)and Remaining Useful Life(RUL)of lithium-ion batteries(LIBs)is crucial for the continuous and stable operation of battery management ***,due to the complex internal chemical systems of LIBs and the nonlinear degradation of their performance,direct measurement of SOH and RUL is *** address these issues,the Twin Support Vector Machine(TWSVM)method is proposed to predict SOH and ***,the constant current charging time of the lithium battery is extracted as a health indicator(HI),decomposed using Variational Modal Decomposition(VMD),and feature correlations are computed using Importance of Random Forest Features(RF)to maximize the extraction of critical factors influencing battery performance ***,to enhance the global search capability of the Convolution Optimization Algorithm(COA),improvements are made using Good Point Set theory and the Differential Evolution *** Improved Convolution Optimization Algorithm(ICOA)is employed to optimize TWSVM parameters for constructing SOH and RUL prediction ***,the proposed models are validated using NASA and CALCE lithium-ion battery *** results demonstrate that the proposed models achieve an RMSE not exceeding 0.007 and an MAPE not exceeding 0.0082 for SOH and RUL prediction,with a relative error in RUL prediction within the range of[-1.8%,2%].Compared to other models,the proposed model not only exhibits superior fitting capability but also demonstrates robust performance.

关键词： State of health remaining useful life variational modal decomposition random forest twin support vector machine convolutional optimization algorithm

Efficient photocatalytic reduction of CO2 to formate by a molecular noble metal-free system

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Science China Chemistry 2025年第1期 152-156页

作者： Lihua Zhang Lingjing Chen Huatian Shi Yue Wei Gui Chen Tai-Chu Lau school of Environment and civil Engineering Research Center for Eco-environmental Engineering Dongguan University of Technology Department of Chemistry and Institute of Molecular Functional Materials City University of Hong Kong

Reducing CO2to carbon-neutral solar fuels can not only alleviate the energy demand but also mitigate the greenhouse *** present,developing an efficient non-noble metal photo/electrocatalytic system for converting CO2to a specific product beyond CO is still a big ***,we report a new cobalt complex bearing 2,2′-bi-1,10-phenanthroline ligand that can photocatalytically reduce CO2to formate （HCOO-）.Turnover number （TON） for HCOO-up to 677 with 99%selectivity can be achieved using organic dyes purpurin as photosensitizer and 1,3-dimethyl-2-phenyl-2,3-dihydro-1H-benzo[d]imidazole （BIH） as sacrificial reductant in a CO2-saturated NMP/TEA （v/v,3:1） solution under visible light *** potential electrolysis at-1.41 V （***/Ag Cl） in the presence of 12 m M Et3NHBF4also produced HCOO-with Faradaic efficiency of 39%.Spectroscopic and electrochemical studies suggest that a[CoI-H]species is the key intermediate for CO2reduction.

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