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Exploration of the coupled lattice Boltzmann model based on a multiphase field model:A study of the solid-liquid-gas interaction mechanism in the solidification process

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Chinese Physics B 2024年第3期33卷 638-648页

作者：朱昶胜王利军高梓豪刘硕李广召 College of Computer and Communication Lanzhou University of TechnologyLanzhou 730050China State Key Laboratory of Gansu Advanced Processing and Recycling of Non-Ferrous Metal Lanzhou University of TechnologyLanzhou 730050China Institute of Modern Physics Chinese Academy of SciencesLanzhou 730000China

A multiphase field model coupled with a lattice Boltzmann(PF-LBM)model is proposed to simulate the distribution mechanism of bubbles and solutes at the solid-liquid interface,the interaction between dendrites and bubbles,and the effects of different temperatures,anisotropic strengths and tilting angles on the solidified organization of the SCN-0.24wt.%butanedinitrile alloy during the solidification *** model adopts a multiphase field model to simulate the growth of dendrites,calculates the growth motions of dendrites based on the interfacial solute equilibrium;and adopts a lattice Boltzmann model(LBM)based on the Shan-Chen multiphase flow to simulate the growth and motions of bubbles in the liquid phase,which includes the interaction between solid-liquid-gas *** simulation results show that during the directional growth of columnar dendrites,bubbles first precipitate out slowly at the very bottom of the dendrites,and then rise up due to the different solid-liquid densities and pressure *** bubbles will interact with the dendrite in the process of flow migration,such as extrusion,overflow,fusion and *** the case of wide gaps in the dendrite channels,bubbles will fuse to form larger irregular bubbles,and in the case of dense channels,bubbles will deform due to the extrusion of *** the simulated region,as the dendrites converge and diverge,the bubbles precipitate out of the dendrites by compression and diffusion,which also causes physical phenomena such as fusion and spillage of the *** results reveal the physical mechanisms of bubble nucleation,growth and kinematic evolution during solidification and interaction with dendrite growth.

关键词： multiphase field model lattice Boltzmann model(LBM) Shan-Chen multiphase flow solidification organization

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Vision-based survey method for extraordinary loads on buildings

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Frontiers of Structural and Civil Engineering 2024年第6期18卷 815-831页

作者： Yang li jun CHEN Pengcheng wang College of Civil Engineering Tongji UniversityShanghai 200092Chinab China United Engineering Co.Ltd. Hangzhou 310052China State Key Laboratory of Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shanghai Key Laboratory of Engineering Structure Safety Shanghai Research Institute of Building Sciences Co.Ltd.Shanghai 200032China

The statistical modeling of extraordinary loads on buildings has been stagnant for decades due to the laborious and error-prone nature of existing survey methods,such as questionnaires and verbal *** study proposes a new vision-based survey method for collecting extraordinary load data by automatically analyzing surveillance *** this purpose,a crowd head tracking framework is developed that integrates crowd head detection and reidentification models based on convolutional neural networks to obtain head trajectories of the crowd in the survey *** crowd head trajectories are then analyzed to extract crowd quantity and velocities,which are the essential factors for extraordinary *** survey areas with frequent crowd movements during temporary events,the equivalent dynamic load factor can be further estimated using crowd velocity to consider dynamic effects.A crowd quantity investigation experiment and a crowd walking experiment are conducted to validate the proposed survey *** experimental results prove that the proposed survey method is effective and accurate in collecting load data and reasonable in considering dynamic effects during extraordinary *** proposed survey method is easy to deploy and has the potential to collect substantial and reliable extraordinary load data for determining design load on buildings.

关键词： load survey extraordinary load live load object detection multiple-object tracking

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Role of c-jun NH_(2)-terminal kinase-mediated mitogen-activated protein kinase pathway in response to pesticides in Apis cerana cerana

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Insect Science 2023年第1期30卷 47-64页

作者： Xiao-Jing Niu li-jun wang Hui Meng Hong-Fang wang Bao-Hua Xu Chen wang State Key Laboratory of Crop Biology College of Life SciencesShandong Agricultural UniversityTaianShandong ProvinceChina College of Animal Science and Technology Shandong Agricultural UniversityTaianShandong ProvinceChina

The mitogen-activated protein kinase(MAPK)cascade pathway plays an important role in regulating stress *** function of the c-jun NH_(2)-terminal kinase(JNK),a component of the MAPK cascade pathway,in Apis cerana cerana(Acc)remains ***,JNK was isolated and identified from *** analyses revealed there is a typical serine/threonine protein kinase catalytic domain in the AccJNK *** expression profile analysis showed that AccJNK was significantly induced by pesticide *** further explore the functional mechanisms of AccJNK,a yeast 2-hybrid screen was performed,activator protein-1(AP-1)was screened as the interaction partner of AccJNK,and the interaction relationship was further verified by pull-down *** real-time polymerase chain reaction showed the expression pattern of AccAP-I was similar to that of *** a knockdown of AccJNK or AccAP-I by RNA interference,the survival rate of Acc after pesticide treatments ***,the expression levels of antioxidant-related genes and the activities of antioxidant enzymes increased,suggesting that the knockdown of AccJNK or AccAP-I increased the antioxidant capacity of *** study revealed that the JNK-mediated MAPK pathway responds to pesticide stress by altering the antioxidant capacity of Acc.

关键词： Apis cerana cerana MAPK cascade oxidative stress pesticide stress RNA interference

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Prediction models of burst strength degradation for casing with considerations of both wear and corrosion

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Petroleum Science 2024年第1期21卷 458-474页

作者： Jie-li wang Wen-jun Huang De-li Gao MOE Key Laboratory of Petroleum Engineering China University of PetroleumBeijing102249China State Key Laboratory of Petroleum Resources and Prospecting China University of PetroleumBeijing102249China

Casing wear and casing corrosion are serious problems affecting casing integrity failure in deep and ultra-deep *** paper aims to predict the casing burst strength with considerations of both wear and ***,the crescent wear shape is simplified into three categories according to common mathematical ***,based on the mechano-electrochemical(M-E)interaction,the prediction model of corrosion depth is built with worn depth as the initial condition,and the prediction models of burst strength of the worn casing and corroded casing are ***,the accuracy of different prediction models is validated by numerical simulation,and the main influence factors on casing strength are *** last,the theoretical models are applied to an ultra-deep well in Northwest China,and the dangerous well sections caused by wear and corrosion are predicted,and the corrosion rate threshold to ensure the safety of casing is *** results show that the existence of wear defects results in a stress concentration and enhanced M-E interaction on corrosion depth *** accuracy of different mathematical models is different:the slot ring model is most accurate for predicting corrosion depth,and the eccentric model is most accurate for predicting the burst strength of corroded *** burst strength of the casing will be overestimated by more than one-third if the M-E interaction is neglected,so the coupling effect of wear and corrosion should be sufficiently considered in casing integrity evaluation.

关键词： Deep well Casing integrity Casing wear Casing corrosion Burst strength

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Evolution of research on climate risk insurance:A bibliometric analysis from 1975 to 2022

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气候变化研究进展:英文版 2023年第4期14卷 592-604页

作者： Yang-Han liN li-jun wang Xin-Yang SHI Min-Peng CHEN School of Agricultural Economics and Rural Development Renmin University of ChinaBeijing 100872China School of Environment and Natural Resources Renmin University of ChinaBeijing 100872China School of International Studies Renmin University of ChinaBeijing 100872China

Insurance against climate risk is essential for mitigating the adverse effects of climate ***,theoretical consensus regarding climate risk insurance remains elusive,and the implementation of climate insurance policies varies markedly between countries owing to various *** study conducted bibliometric analysis of 1082 relevant publications(1975–2022)to determine the theoretical basis,evolution of research hotspots,and methodologies associated with climate risk *** insurance publications are growing at an average annual rate of 8.9%,with more than 2333 authors from 1103 organizations in 78 countries publishing on the *** the basis of milestones of global climate change assessment,i.e.,the publication of the Fourth and Fifth Assessment Reports of the Intergovernmental Panel on Climate Change,climate insurance research can be divided into three major *** the start-up phase(1975–2007),research schemes examined the feasibilities and potentials of the National Flood Insurance Program in the United States,and the socioeconomic implications of transferring climate risk through *** methodologies used in these studies were relatively simple owing to lack of comprehensive *** on flood insurance increased rapidly during the development phase(2008–2014),with increasing emphasis on the possibility of developing a flood insurance market in the *** utilized catastrophe modeling and probabilistic approaches to estimate natural disaster losses and financial *** boom phase(2015–2022)involved more research on the affordability of climate risk insurance given income *** topic of climate insurance and the scope of its impact have developed global and interdisciplinary characteristics in terms of journal,sector,and disciplinary *** the future,a trend might develop whereby big data will be combined with artificial intelligence and machine learning to design and implement index insu

关键词： Climate risk insurance Climate change Bibliometric analysis Adaptation Network analysis

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Cerium oxide inclusion nucleation mechanism based on classical nucleation theory and two-step nucleation

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Journal of Rare Earths 2024年第4期42卷 793-802页

作者： Yutang li jun wang linzhu wang Chaoyi Chen Shufeng Yang junqi li Xiang li School of Materials and Metallurgy Guizhou UniversityGuiyang550025China State Key Laboratory of Public Big Data Guizhou UniversityGuiyang550025China School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Department of Materials&Metallurgy Engineering Guizhou Institute of TechnologyGuiyang550003China

It is challenging to assess the mechanism responsible for the nucleation of inclusions in metals at high *** present work therefore systematically investigates the nucleation of cerium oxide inclusions according to classical nucleation theory and a two-step nucleation *** nucleation rates and nucleation radii of these inclusions are obtained,and the results demonstrate a considerable difference between theoretical and experimental *** the basis of a two-step nucleation mechanism,(CeO_(2))_(n) and(Ce_(2)O_(3))_(n)(n=1-6)clusters were constructed and the thermodynamic properties of both these clusters and of cerium oxide nanoparticles were *** addition,the entropies and heat capacity changes of cerium oxides were determined using first principles calculations and are found to be consistent with literature *** present data indicate that the cerium oxide inclusion nucleation pathway can be summarized as[Ce]+[O]→(CeO_(2))n/(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(n)→(Ce_(2)O_(3))_(2)→core(Ce_(2)O_(3)crystal)-shell((Ce_(2)O_(3))_(2) cluster)nanoparticles→(Ce_(2)O_(3))bulk.

关键词： Cerium oxide inclusion Classical nucleation theory Two-step nucleation mechanism First principles Rare earths

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Experimental Study of Temperature Control Based on Composite Phase Change Materials during Charging and Discharging of Battery

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Journal of Thermal Science 2024年第2期33卷 578-590页

作者： li Xiaolin wang jun CAO Wenxiang ZHANG Xuesong School of Automotive and Traffic Engineering Jiangsu UniversityZhenjiang212013China

This study is to utilize the heat-absorbing and releasing capabilities of phase change materials(PCM)to regulate the surface temperature fluctuations of batteries during charging and *** goal is to keep the battery within the optimal operating temperature *** impact of PCM thickness and phase change temperature on battery temperature is investigated by encircling a cylindrical battery with a PCM *** improve the thermal conductivity of PCM,expanded graphite(EG) is added to make a composite phase change material(CPCM),and the effects of various EG mass ratios on battery surface temperature and CPCM utilization level are *** findings indicate that increasing PCM thickness effectively extends temperature control time,but its impact is *** difference in phase change temperature of PCM controls the battery temperature in different temperature *** phase change temperatures are unsuitable for controlling battery temperature in high temperature *** addition of EG enhances the thermal conductivity of PCM,leading to further control of battery *** results show that the addition of 6%(mass ratio) EG to CPCM extends the effective temperature control time by 11 min and improves by 28% compared to a single *** CPCM utilization is also more satisfactory and achieved a balance between heat storage and thermal conductivity in a battery thermal management system(BTMS) based on PCM.

关键词： phase change material expanded graphite thermal management system effective control time

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Optimal Model Average Prediction in Orthogonal Kriging Models

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Journal of Systems Science & Complexity 2024年第3期37卷 1080-1099页

作者： wang jun HE Jiabei liANG Hua li Xinmin School of Mathematics and Statistics Qingdao UniversityQingdao 266071China Department of Statistics George Washington UniversityWashington DC 20052USA

The main objective of this paper is to consider model averaging methods for kriging *** paper proposes a Mallows model averaging procedure for the orthogonal kriging model and demonstrate the asymptotic optimality of the model averaging estimators in terms of mean square *** studies are conducted to evaluate the performance of the proposed method and compare it with the competitors to demonstrate its *** authors also analyse a real dataset for an illustration.

关键词： Asymptotic optimality Mallows criterion optimal model averaging orthogonal kriging model

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DepthGAN: GAN-based depth generation from semantic layouts

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Computational Visual Media 2024年第3期10卷 505-522页

作者： Yidi li jun Xiao Yiqun wang Zhengda Lu School of Artiﬁcial Intelligence University of Chinese Academy of SciencesBeijingChina College of Computer Science Chongqing UniversityChongqingChina

Existing GAN-based generative methodsare typically used for semantic image synthesis. Wepose the question of whether GAN-based architecturescan generate plausible depth maps and ﬁnd thatexisting methods have difficulty in generating depthmaps which reasonably represent 3D scene structuredue to the lack of global geometric ***, we propose DepthGAN, a novel method ofgenerating a depth map using a semantic layout asinput to aid construction, and manipulation of wellstructured 3D scene point clouds. Speciﬁcally, weﬁrst build a feature generation model with a cascadeof semantically-aware transformer blocks to obtaindepth features with global structural *** our semantically aware transformer block, wepropose a mixed attention module and a semanticallyaware layer normalization module to better exploitsemantic consistency for depth features ***, we present a novel semantically weighteddepth synthesis module, which generates adaptivedepth intervals for the current scene. We generate theﬁnal depth map by using a weighted combination ofsemantically aware depth weights for different depthranges. In this manner, we obtain a more accuratedepth map. Extensive experiments on indoor andoutdoor datasets demonstrate that DepthGAN achievessuperior results both quantitatively and visually for thedepth generation task.

关键词： depth map generation generative model transformer scene generation

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Two-way shape memory effect in a Ti-Zr-Nb-Ta high-temperature shape memory alloy

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Rare Metals 2024年第3期43卷 1257-1262页

作者： Cheng-Yang Xiong Tuo li jun wang Yan li School of Materials Science and Engineering Beihang UniversityBeijing100191China

The two-way shape memory effect in a Ti-18.5Zr-10Nb-3.5Ta high-temperature shape memory alloy was investigated.X-ray diffraction measurem ent shows that the alloy is composed of orthorhombicα"-martensite.ωphase is not found in Ti-18.5Zr-10Nb-3.5Ta alloy due to the suppressing effect of Ta ***α"-martensite laths are found in the transmission electron microscope observation;after the bending deformation,there appear a lot of *** alloy exhibits a shape memory strain of 3.8%aud a high reverse martensite transformation start temperature of 464 *** maximum two-way shape memory strain of 1.2%is obtained in the alloy with the prebending training strain of 10%.The mechanism can be ascribed to the effect of internal stress field caused by dislocations.

关键词： Ti-Zr Shape memory alloys Two-way shape memory effect

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