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Wireless remote spatiotemporal monitoring of high-fill foundation deformation

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Journal of Mountain Science 2023年第6期20卷 1620-1638页

作者： yanG Xiao-hui LI Zhi-qian zhu yan-peng GUO Nan School of Civil Engineering Lanzhou University of TechnologyLanzhou 730050China Western Engineering Research Center of Disaster Mitigation in Civil Engineering of Ministry of Education Lanzhou University of TechnologyLanzhou 730050China

The spatial and temporal deformation patterns and deformation control indicators of highfill foundations directly affect the design,construction and operational safety of high-fill *** situ monitoring can comprehensively reflect the deformation of high-fill during and after *** this paper,we have first designed and installed an integrated wireless remote monitoring system for high-fill to achieve real-time dynamic monitoring of settlement,pore water pressure and soil pressure of the fill *** on the monitoring results of nearly one year of the construction period and two years after construction,it was found that the deformation amount and deformation rate of the high-fill foundation showed a non-linear growth relationship with the filling rate and filling *** settlement deformation of the high-fill foundation during the loading period was mainly dominated by the original foundation soil,accounting for 54.4%of the total settlement on average;the settlement deformation during the post-construction period was mainly dominated by the filling body,accounting for 77.04%of the total settlement on average,and the settlement deformation during the post-construction period mainly occurred in the first year after *** analysis of the deformation mechanism suggests that the deformation of the filling body is dominated by exhaust consolidation during the loading period and drainage consolidation during the post-construction period;the deformation of the original foundation soil is dominated by drainage consolidation during the loading period and drainage consolidation develops slowly during the post-construction *** is recommended that the original foundation should be reinforced before the large area filling construction,and that the filling rate should be strictly controlled during *** research results can provide a scientific basis for deformation calculation and stability assessment of high-fill foundatio

关键词： High-fill engineering Wireless remote monitoring Foundation deformation Spatiotemporal law Settlement after construction

Microstructural evolution of Au-Sn solder prepared by laminate rolling during annealing process

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Rare Metals 2011年第6期30卷 627-632页

作者： WEI Xiaofeng WANG Richu FENG yan zhu Xuewei peng Chaoqun School of Materials Science and Engineering Central South University Changsha 410083 China

The microstructural evolution and inteffacial reaction of the Au/Sn/Au/Sn/Au/Sn/Au couples were investigated during annealing at 453, 523, and 543 K for up to 240 h. The Au/Sn combination formed a rapid diffusion system. Even in rolled Au-Sn solder, three phases, such as AuSn, AuSn2, and AuSn4, were formed. After initial annealing at 453 K, the diffusion layers of AuSn, AuSn2, and AuSn4, which were formed after rolling, expanded gradually and then fully transformed into phase （containing Sn from 10% to 18.5%, mole fraction） and 6 （AuSn） phase. As a whole, the microstmcture of the couple was stable during annealing at 453 K. The solid-state interracial reaction was much faster at 523 K than at 453 K. After annealing at 523 K for 6 h, the AuSn, AuSn2, and AuSn4 were fully transformed into the phase and phase （AuSn）. In spite of the prolonged annealing time for up to 240 h, no significant change of the interfacial microstructure occurred, and the microstructure of the couple was stable during annealing at 523 K. When annealing at 543 K, however, the interfacial of Au/Sn was transformed into solid-liquid state, and the whole couple formed a eutecfic structure rapidly, causing the solder to be brittle. The study results clearly demonstrate that the service temperature of the Au-Sn solder should be lower than 543 K.

关键词： Au-Sn solders intermetallic compounds (IMCs) rolling-annealing method interfacial reaction microstructural evolution

Automatic detection and assessment of crack development in ultra-high performance concrete in the spatial and Fourier domains

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Frontiers of Structural and Civil Engineering 2024年第3期18卷 350-364页

作者： Jixing CAO Yao ZHANG Haijie HE Weibing peng Weigang ZHAO Zhiguo yan Hehua zhu School of Safety Engineering and Emergency Management Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Civil Engineering and Architecture Zhejiang UniversityHangzhou 310058China College of Civil and Architectural Engineering Taizhou UniversityTaizhou 318000China College of Civil Engineering and Architecture Zhejiang University of TechnologyHangzhou 310014China Department of Geotechnical Engineering Tongji UniversityShanghai 200092China

Automatic detection and assessment of surface cracks are beneficial for understanding the mechanical performance of ultra-high performance concrete(UHPC).This study detects crack evolution using a novel dynamic mode decomposition(DMD)*** this method,the sparse matrix‘determined’from images is used to reconstruct the foreground that contains cracks,and the global threshold method is adopted to extract the crack *** application of the DMD method to the three-point bending test demonstrates the efficiency in inspecting cracks with high ***,the geometric features,including the area and its projection in two major directions,are evaluated over *** relationship between the geometric properties of cracks and load-displacement curves of UHPC is *** to the irregular shape of cracks in the spatial domain,the cracks are then transformed into the Fourier domain to assess their *** indicate that crack patterns in the Fourier domain exhibit a distinct concentration around a central ***,the power spectral density of cracks exhibits an increasing trend over *** investigation into crack evolution in both the spatial and Fourier domains contributes significantly to elucidating the mechanical behavior of UHPC.

关键词： dynamic mode decomposition ultra-high performance concrete crack detection geometric features Fourier domain

Thermal and mechanical behavior of casting copper alloy wheel during wheel and belt continuous casting process

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China Foundry 2024年第1期21卷 82-90页

作者： Kun Gao yan peng School of Mechanical Engineering Yanshan UniversityQinhuangdao 066004HebeiChina

To investigate the thermal and mechanical behavior of casting wheel,a two-dimensional thermoelastic-plastic finite element model was used to predict the temperature,stress and distortion distribution of the casting wheel during the wheel and belt continuous casting *** effects of grinding thickness and casting speed on the thermal and mechanical behaviors of the center of the hot face of the casting wheel were discussed in *** each rotation,the casting wheel passes through four different spray *** results show that the temperature distribution of the casting wheel in different spray zones is similar,the temperature of the hot face is the highest and the temperature reaches the peak in the spray zoneⅢ.The stress and distortion depend on the temperature distribution,and the maximum stress and distortion of the hot face are 358.2 MPa and 1.82 mm,*** temperature at the center of the hot face decreases with increasing grinding thickness and increases with increasing casting speed.

关键词： casting wheel finite element model grinding thickness casting speed hot face spray zones

Numerical simulation of fluid flow and free surface fluctuations during wheel and belt casting process

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Journal of Iron and Steel Research International 2024年第5期31卷 1117-1126页

作者： Kun Gao yan peng National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan UniversityQinhuangdao066004HebeiChina

The unstable fluid flow and severe free surface fluctuations in the wheel and belt caster can affect the quality of the cast *** lower level height tends to entrap inclusions in the molten *** the other hand,the higher level height makes the production process more dangerous due to the overflow of high temperature fluid from the mold.A computational model of the molten metal pouring process was *** transient fluid flow and free surface fluctuations behavior were calculated using the three-dimensional large eddy simulation model and the volume of fluid *** results show that the flow velocity of the main jet gradually decreases under the influence of the low kinetic energy fluid in the *** is an obvious oscillation in the tail of the jet,while the flow field is asymmetric in *** jet is closer to the inside radius side due to the Coanda effect,and there is a recirculation zone on the inside radius and the outside radius respectively,according to the 10 s time-averaged *** with the industrial observation and simulation results,the shape of the free surface is a wave that varies with *** addition,the free surface height is lowest and the flow velocity is highest in the region near the jet.

关键词： Fluid flow Free surface Wheel and belt caster Large eddy simulation Volume of fluid method

Atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering correction

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Nuclear Science and Techniques 2024年第3期35卷 40-52页

作者： Ding-Han zhu Xiong Zhang Xiao-Qiang Li peng Li yan-Bin Wang Shuang Zhang State Key Laboratory of NBC Protection for Civilian Beijing 102205China

In high-altitude nuclear detonations,the proportion of pulsed X-ray energy can exceed 70%,making it a specific monitoring signal for such *** pulsed X-rays can be captured using a satellite-borne X-ray detector following atmospheric *** quantitatively analyze the effects of different satellite detection altitudes,burst heights,and transmission angles on the physical processes of X-ray transport and energy fluence,we developed an atmospheric transmission algorithm for pulsed X-rays from high-altitude nuclear detonations based on scattering *** proposed method is an improvement over the traditional analytical method that only computes direct-transmission *** traditional analytical method exhibits a maximum relative error of 67.79% compared with the Monte Carlo *** improved method reduces this error to within 10% under the same conditions,even reaching 1% in certain ***,its computation time is 48,000 times faster than that of the Monte Carlo *** results have important theoretical significance and engineering application value for designing satellite-borne nuclear detonation pulsed X-ray detectors,inverting nuclear detonation source terms,and assessing ionospheric effects.

关键词： High-altitude nuclear detonation Atmospheric transmission Pulsed X-rays Scattering correction Analytical method Monte Carlo method

Effect of Phase Separation Size on the Properties of Self-healing Elastomer

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Chinese Journal of Polymer Science 2024年第6期42卷 798-804页

作者： Jun Xu Lei zhu Xian-Qi Feng Cong Sui Wen-peng Zhao Shou-Ke yan School of Chemical Engineering Qingdao University of Science&TechnologyQingdao266042China College of Engineering Yanching institute of TechnologyLangfang065210China Key Laboratory of Rubber-plastics Qingdao University of Science&TechnologyQingdao266042China State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing100029China

Regulation of phase structure has been recognized as one of the most effective ways to fabricate self-healing polymers with high mechanical *** mechanical properties of the resultant polymers are certainly affected by the size of separated phase ***,the study on this aspect is absence,because it can hardly exclude the influence of variation in monomer proportion required for tuning the separated phase ***,we report the first study on tuning the phase size through reversible addition-fragmentation chain transfer(RAFT)polymerization without changing the proportion of *** expected,the size of separated phase has been successfully mediated from 15 nm to 9 nm by tuning the molecular weight of the chain transfer *** is found that the mechanical strength and the self-healing efficiency of the resultant polymers increase simultaneously with the decrease of phase *** study on the formation kinetics of hydrogen bonds reveals that the decrease of phase size can facilitate the re-bonding rate of hydrogen bonds,even if the migration of polymer chains is restricted.

关键词： Self-healing polymers Phase separation Reversible addition-fragmentation chain transfer

Large eddy simulation study on drag reduction performance of array-based plasma synthetic jet actuators

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Chinese Journal of Aeronautics 2024年第10期37卷 118-135页

作者： Yunan WANG Zhenbing LUO Wei XIE yan ZHOU Qiang LIU Wenqiang peng Yinxin zhu College of Aerospace Science and Engineering National University of Defense TechnologyChangsha 410073China

Large Eddy Simulation(LES)is first used to investigate the drag reduction effect of an array-based configuration of Plasma Synthetic Jet Actuators(PSJAs)on a hemisphere in supersonic inflow,and analyze the effect of energy allocation and array angle on the drag reduction performance of opposing Plasma Synthetic Jet(PSJ)in this *** simulation results have been compared with experimental data,confirming the validity of the simulation *** results show that different energy allocations have a significant effect on the drag of the ***,the effect of the change in array angle on the drag of the hemisphere is not as noticeable as the effect caused by energy *** regions between the two PSJAs occur,which undermine the effectiveness of drag *** Turbulent Kinetic Energy(TKE)regions primarily concentrate on the core region of the jet and downstream of the bow *** influence of the array angle on TKE is most evident in the downstream region of the exits of the PSJs on both *** evolution of the coherent structures reveals that as the PSJ intensity decreases,the largescale vortices progressively break up into smaller-scale vortices,and energy is also transferred from large-scale structures to small-scale structures.

关键词： Plasma synthetic jet Shock wave Large eddy simulation Drag reduction Flow control

Direct conversion of CO and H_(2)O to hydrocarbons at atmospheric pressure using a TiO_(2-x)/Ni photothermal catalyst

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Science China Materials 2024年第3期67卷 1009-1010页

作者： yan zhu School of Chemistry and Chemical Engineering Nanjing UniversityNanjing 210093China

Generating high-value chemical compounds by catalytically converting carbon resources—typically derived from coal and biomass, etc.—is crucial. It is more meaningful to achieve“carbon neutrality” and lower production costs by utilizing industrial waste carbon sources, such as steel mill waste gases,which are typically intended for direct emission or burning into CO_(2).

关键词： typically utilizing meaningful