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Time-Periodic Solutions to Quasilinear Hyperbolic Systems on General Networks

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Chinese Annals of Mathematics,Series B 2024年第1期45卷 41-72页

作者： peng QU School of Mathematical Sciences Fudan UniversityShanghai 200433China

For quasilinear hyperbolic systems on general networks with time-periodic boundary-interface conditions with a dissipative structure,the existence and stability of the time-periodic classical solutions are discussed.

关键词： Time-periodic solution Quasilinear hyperbolic system General net-work Classical solution Asymptotic stability

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

Two-Stage Online Debiased Lasso Estimation and Inference for High-Dimensional Quantile Regression with Streaming Data

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Journal of Systems Science & Complexity 2024年第3期37卷 1251-1270页

作者： peng Yanjin WANG Lei School of Statistics and Data Science KLMDASRLEBPS and LPMCNankai UniversityTianjin 300071China

In this paper,the authors propose a two-stage online debiased lasso estimation and statistical inference method for high-dimensional quantile regression(QR)models in the presence of streaming *** the first stage,the authors modify the QR score function based on kernel smoothing and obtain the online lasso smoothed QR estimator through iterative *** estimation process only involves the current data batch and specific historical summary statistics,which perfectly accommodates to the special structure of streaming *** the second stage,an online debiasing procedure is carried out to eliminate biases caused by the lasso penalty as well as the accumulative approximation error so that the asymptotic normality of the resulting estimator can be *** authors conduct extensive numerical experiments to evaluate the performance of the proposed *** experiments demonstrate the effectiveness of the proposed method and support the theoretical *** application to the Beijing PM2.5 Dataset is also presented.

关键词： Adaptive tuning asymptotic normality debiased lasso online updating quantile regres-sion

Electronic origin of structural degradation in Li-rich transition metal oxides:The case of Li_(2)MnO_(3)and Li_(2)RuO_(3)

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Journal of Semiconductors 2024年第4期45卷 82-86页

作者： peng Zhang Key Laboratory of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province College of Physics andOp toelec-tronic EngineeringShenzhen UniversityShenzhen 518060China

Li_(2)MnO_(3)and Li_(2)RuO_(3)represent two prototype Li-rich transition metal(TM)oxides as high-capacity cathodes for Li-ion batteries,which have similar crystal structures but show quite different cycling ***,based on the first-princi-ples calculations,we systematically studied the electronic structures and defect properties of these two Li-rich cathodes,in order to get more understanding on the structural degradation mechanism in Li-rich TM *** calculations indicated that the structural and cycling stability of Li_(2)MnO_(3)and Li_(2)RuO_(3)depend closely on their electronic structures,especially the energy of their highest occupied electronic states(HOS),as it largely determines the defect properties of these *** Li_(2)MnO_(3)with low-energy HOS,we found that,due to the defect charge transfer mechanism,various defects can form spontaneously in its host structure as Li ions are extracted upon delithiation,which seriously deteriorates its structural and cycling *** for Li_(2)RuO_(3),on the other hand,we identified that the high-energy HOS prevents it from the defect formation upon delithi-ation and thus preserve its cycling *** studies thus illustrated an electronic origin of the structural degradation in Li-rich TM oxides and implied that it is possible to improve their cycling performances by carefully adjusting their TM compo-nents.

关键词： defects Li-ion batteries first-principles calculations

Fourth-order phase-field modeling for brittle fracture in piezoelectric materials

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Applied Mathematics and Mechanics(English Edition) 2024年第5期45卷 837-856页

作者： Yu TAN Fan peng Chang LIU Daiming peng Xiangyu LI State Key Laboratory of Geohazard Prevention and Geoenvironment Protection Chengdu University of TechnologyChengdu 610059China College of Science Chang'an UniversityXi'an 710064China Applied Mechanics and Structure Safety Key Laboratory of Sichuan Province School of Mechanics and Aerospace EngineeringSouthwest Jiaotong UniversityChengdu 610031China

Failure analyses of piezoelectric structures and devices are of engineering and scientific *** this paper,a fourth-order phase-field fracture model for piezoelectric solids is developed based on the Hamilton *** typical electric boundary conditions are involved in the present model to characterize the fracture behaviors in various physical situations.A staggered algorithm is used to simulate the crack *** polynomial splines over hierarchical T-meshes(PHT-splines)are adopted as the basis function,which owns the *** numerical simulations are performed to study the influence of the electric boundary conditions and the applied electric field on the fracture behaviors of piezoelectric *** electric boundary conditions may influence crack paths and fracture loads *** present research may be helpful for the reliability evaluation of the piezoelectric structure in the future applications.

关键词： isogeometric analysis(IGA) brittle fracture fourth-order phase-field model piezoelectric solid

A Weighted Flow related to a Trudinger–Moser Functional on Closed Riemann Surface

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Acta Mathematica Sinica,English Series 2024年第9期40卷 2244-2262页

作者： peng Xiu YU School of Mathematics Renmin University of ChinaBeijing 100872P.R.China

In this paper,with(Σ,g)being a closed Riemann surface,we analyze the possible concentration behavior of a heat flow related to the Trudinger–Moser *** obtain a long time existence for the *** along some sequence of times t_(k)→+∞,we can deduce the convergence of the flow in H2(Σ).Furthermore,the limit function is a critical point of the Trudinger–Moser functional under certain constraint.

关键词： Trudinger-Moser inequality global convergence heat flow

Bio-inspired inorganic-protein coating on Mg-based biomaterials for bioengineering applications

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Science China Materials 2024年第5期67卷 1678-1680页

作者： Xuwen peng Haolan Xu Department of Chemistry Engineering Tsinghua UniversityBeijing100084China Department of Chemical and Materials Engineering University of AlbertaEdmontonAlbertaT6G 1H9Canada Future Industries Institute UniSA STEMUniversity of South AustraliaMawson Lakes CampusAdelaideSouth Australia5095Australia

Developing smart and advanced functional materials inspired by the unparalleled complexity and efficiency of biological tissues has received much attention across various *** alloys,particularly pure magnesium,have emerged as notable candidates in orthopedics and dentistry due to their exceptional biocompatibility,degradability,and ability to promote bone regeneration[1].However,the highly reactive chemical nature of magnesium and its rapid degradation upon exposure to water.

关键词： coating alloys magnesium

CFD-DEM study on the synergistic effect of coke consumption and particle dynamics in the blast furnace raceway

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Particuology 2024年第6期89卷 270-278页

作者： peng Xu peng Han Zhijun He Xizhong An Kang Sun Lihua Gao Key Laboratory of Green Low-Carbon and Intelligent Metallurgy School of Materials and MetallurgyUniversity of Science and Technology LiaoningAnshan 114000China Key Laboratory for Ecological Metallurgy of Multimetallic Mineral of Ministry of Education School of MetallurgyNortheastern UniversityShenyang110819China

In this study,the gas-solid flow process in the blast furnace raceway is numerically simulated using coupled computational fluid dynamics and the discrete element method(CFD-DEM).The coke reaction kinetics data are imported into the DEM model to reproduce the consumption process of each coke *** effects of inlet gas velocity and angle on the morphology of the raceway,coke consumption rate,coke bed temperature,and particle size distribution in the blast process are systematically investigated and *** results show that the consumption of coke particles promotes the formation of raceways during the blast *** the same time,a coke mixture layer is produced at the edge of the *** higher the inlet gas velocity,the thicker the coke mixture layer in the middle and upper parts of the raceway region,and the larger the proportion of small particles in the coke mixture *** effect of the inlet gas angle on the raceway region is less than the inlet gas ***,with the increase in the inlet gas angle,the high-temperature region of the coke bed extends downward gradually,which is conducive to activating the hearth.

关键词： Blast furnace Raceway Multiphase flow CFD-DEM Modeling