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An analytical model to predict diffusion induced intermetallic compounds growth in Cu-Sn-Cu sandwich structures

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Theoretical & Applied Mechanics Letters 2020年第1期10卷 33-37页

作者： Yuexing Wang Yao Yao leon keer Institute of Electronic Engineering China Academy of Engineering PhysicsMianyang 621999China School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi'an 710072China Department of Civil and Environmental Engineering Northwestern UniversityEvanstonIL 60208USA

A mass diffusion model is developed to describe the growth kinetics of Cu6Sn5 intermetallic compounds(IMC)in the Cu-Sn-Cu sandwich *** proposed model is based on the local interfacial mass conversation law where interfacial Cu/Sn reactions and atomic diffusion are *** analysis shows that the IMC thickness growth is proportional to the square root of the product of the diffusion coefficient and *** proposed model can explain the polarity effect of electromigration on kinetics of IMC growth where all the parameters have clear physical *** theoretical predictions are compared with experimental results and show reasonable accuracy.

关键词： Intermetallic compounds Polarity effect Electromigration Diffusion Size effect

Factors Influencing the Spatial Variability of Air Temperature Urban Heat Island Intensity in Chinese Cities

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Advances in Atmospheric Sciences 2024年第5期41卷 817-829页

作者： Heng LYU Wei WANG keer ZHANG Chang CAO Wei XIAO Xuhui LEE Key Laboratory of Meteorological Disaster Ministry of Education(KLME)/Collaborative Innovation Center on Forecast and Evaluation of Meteorological Disasters(CIC-FEMD)/Key Laboratory of Ecosystem Carbon Source and SinkChina Meteorological Administration(ECSS-CMA)/Jiangsu Key Laboratory of Agricultural MeteorologyNanjing University of Information Science&TechnologyNanjing 210044China Key Laboratory of Urban Meteorology China Meteorological AdministrationBeijing 100089China School of the Environment Yale UniversityNew HavenCT 06511USA

Few studies have investigated the spatial patterns of the air temperature urban heat island(AUHI)and its controlling *** this study,the data generated by an urban climate model were used to investigate the spatial variations of the AUHI across China and the underlying climate and ecological drivers.A total of 355 urban clusters were *** performed an attribution analysis of the AUHI to elucidate the mechanisms underlying its *** results show that the midday AUHI is negatively correlated with climate wetness(humid:0.34 K;semi-humid:0.50 K;semi-arid:0.73 K).The annual mean midnight AUHI does not show discernible spatial patterns,but is generally stronger than the midday *** urban–rural difference in convection efficiency is the largest contributor to the midday AUHI in the humid(0.32±0.09 K)and the semi-arid(0.36±0.11 K)climate *** release of anthropogenic heat from urban land is the dominant contributor to the midnight AUHI in all three climate *** rural vegetation density is the most important driver of the daytime and nighttime AUHI spatial variations.A spatial covariance analysis revealed that this vegetation influence is manifested mainly through its regulation of heat storage in rural land.

关键词： air temperature urban heat island spatial variations biophysical drivers Chinese cities climate model

Mitigating the negative catalytic effect of CuO by FAS-17 coated Al nanopowder:Isothermal ageing of Al/CuO nanothermite at 71°C and 60%relative humidity

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Defence Technology（防务技术） 2024年第4期34卷 156-167页

作者： Fuwei Li Qian Wang Jian Cheng Zehua Zhang Yuxuan Zhou keer Ouyang Jianbing Xu Yinghua Ye Ruiqi Shen School of Chemistry and Chemical Engineering Nanjing University of Science&TechnologyNanjing 210094China Micro-Nano Energetic Devices Key Laboratory Ministry of Industry and Information TechnologyNanjing 210094JiangsuChina Institute of Space Propulsion Nanjing University of Science and TechnologyNanjing 210094China

The safety and reliability of weapon systems would be significantly affected by changes in the performance of energetic materials due to ambient temperature and *** have promising applications due to their excellent *** it becomes extremely important to understand their aging and failure process in the environment before using ***,the aging and failure process of Al/CuO in 71°C/60%RH were investigated,and showed that CuO nanoparticles negatively catalyze Al nanopowders,resulting in rapid *** anti-aging effect of FAS-17-coated Al nanopowder was also *** aging process of Al,Al/CuO,and Al@FAS-17/CuO in high humidity and heat environment were revealed by quasi-in situ SEM and TEM *** with the aging of pure Al,the Al nanopowder in the nanothermites strongly agglomerated with the CuO nanopowder and hydrated *** may be caused by CuO catalyzed hydration of Al *** energy release experiments showed that the performance of Al/CuO decreased rapidly and failed to ignite after 4 h of *** contrast,the Al@FAS-17/CuO thermite can achieve long-term stability of up to 60 h in the same environment by simple cladding of *** is found that FAS-17 coated Al nanopowder can prevent both particle agglomeration and water erosion,which is an effective means to make nanothermites application in high humidity and heat environment.

关键词： Al/CuO nanothermite FAS-17 coating Aging and failure process

From the dust:extracellular vesicles as regulators of development and neuroregeneration

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Neural Regeneration Research 2024年第5期19卷 933-934页

作者： leon G.Coleman Jr The University of North Carolina at Chapel Hill School of MedicineDepartment of PharmacologyBowles Center for Alcohol StudiesChapel HillNCUSA

First impressions can have a lasting *** science,this can be especially problematic,because our lack of understanding often causes us to mislabel and thus ignore important biological *** this vein,extracellular vesicles(EVs)were once considered to be“cellular dust”.Similar to the previous concept of“junk DNA”to describe protein non-coding regions,EVs are far more than just cellular *** fact,EVs are emerging as key mediators of intracellular communication across nearly all biological *** includes peripheral immune responses(e.g.,arthropathies and sepsis),intra-organ communication(Seim et al.,2023),and a host of other physiological and pathological states(Figure 1A and B).

关键词： Figure extracellular

APPROXIMATING THE STATIONARY BELLMAN EQUATION BY HIERARCHICAL TENSOR PRODUCTS

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Journal of Computational Mathematics 2024年第3期42卷 638-661页

作者： Mathias Oster leon Sallandt Reinhold Schneider Technische Universität Berlin Strasse des 17.Juni 13510623 BerlinGermany

We treat infinite horizon optimal control problems by solving the associated stationary Bellman equation numerically to compute the value function and an optimal feedback *** dynamical systems under consideration are spatial discretizations of non linear parabolic partial differential equations(PDE),which means that the Bellman equation suffers from the curse of *** non linearity is handled by the Policy Iteration algorithm,where the problem is reduced to a sequence of linear equations,which remain the computational bottleneck due to their high *** reformulate the linearized Bellman equations via the Koopman operator into an operator equation,that is solved using a minimal residual *** the Koopman operator we identify a preconditioner for operator equation,which deems essential in our numerical *** overcome computational infeasability we use low rank hierarchical tensor product approximation/tree-based tensor formats,in particular tensor trains(TT tensors)and multi-polynomials,together with high-dimensional quadrature,*** controlling a destabilized version of viscous Burgers and a diffusion equation with unstable reaction term numerical evidence is given.

关键词： Feedback control Dynamic programming Hamilton-Jacobi-Bellman Tensor product approximation Variational Monte-Carlo

A Dynamic Network Game of the Fintech Industry

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Journal of the Operations Research Society of China 2024年第1期12卷 5-33页

作者： David W.K.Yeung leon A.Petrosyan Ying-Xuan Zhang SRS Consortium for Advanced Study in Cooperative Dynamic Games Shue Yan UniversityHong KongChina Center of Game Theory St Petersburg State UniversitySaint PetersburgRussia Department of Finance Asia UniversityTaichung CityTaiwanChina Faculty of Applied Mathematics-Control Processes and Center of Game Theory St Petersburg StateUniversitySaint PetersburgRussia

Economies of scale,economies of scope,and technology spillover are decisive eco-nomic elements that are crucial to the development in the Fintech *** externalities are often realized through network *** this paper,we presenta dynamic network ofﬁnancialﬁrms which exhibits these decisive *** game equilibria are characterized.A Pareto efﬁcient solution involving col-laboration of allﬁrms is *** obtain a fair-share distribution of cooperativegains,the Shapley value is adopted as the sharing *** distributionmechanisms which guarantee the fulﬁlment of the Shapley value distribution in eachstage of the cooperation duration are derived.

关键词： Network game Network equilibria Shapley value Pareto efﬁcientcooperation

A CFD Model to Evaluate Near-Surface Oil Spill from a Broken Loading Pipe in Shallow Coastal Waters

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Fluid Dynamics & Materials Processing 2024年第1期20卷 59-77页

作者： Portia Felix Lee leon Derek Gay Stefano Salon Hazi Azamathulla Department of Civil and Environmental Engineering The University of the West IndiesSt.AugustineTrinidad and Tobago National Institute of Oceanography and Experimental Geophysics-OGS TriesteItaly

Oil spills continue to generate various issues and concerns regarding their effect and behavior in the marine environment,owing to the related potential for detrimental environmental,economic and social *** is essential to have a solid understanding of the ways in which oil interacts with the water and the coastal ecosystems that are located *** study proposes a simplified model for predicting the plume-like transport behavior of heavy Bunker C fuel oil discharging downward from an acutely-angled broken pipeline located on the water *** results show that the spill overall profile is articulated in three major flow *** first,is the source field,i.e.,a region near the origin of the initial jet,followed by the intermediate or transport field,namely,the region where the jet oil flow transitions into an underwater oil plume flow and starts to move horizontally,and finally,the far-field,where the oil re-surface and spreads onto the shore at a significant distance from the spill *** behavior of the oil in the intermediate field is investigated using a simplified injection-type oil spill model capable of mimicking the undersea trapping and lateral migration of an oil plume originating from a negatively buoyant jet spill.A rectangular domain with proper boundary conditions is used to implement the *** Projection approach is used to discretize a modified version of the Navier-Stokes equations in two dimensions.A benchmark fluid flow issue is used to verify the model and the results indicate a reasonable relationship between specific gravity and depth as well as agreement with the aerial data and a vertical temperature profile plot.

关键词： CFD model Navier-Stokes equations projection method water surface oil spill shallow coastal waters

国际经济秩序转型叙事的再思考:基于补贴规制视角

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国际经贸探索 2024年第7期40卷 105-118页

作者：黄可而武汉大学国际法研究所

随着国际经贸格局发展,关于国际经济秩序“从自由到公平”的转型叙事频繁出现在公共讨论与研究视野。基于补贴规制视角,文章探究国际经济秩序公平转型叙事如何展开、有何疏漏。相对于多边补贴纪律,新兴补贴规则更关注公平贸易与竞争公... 详细信息

随着国际经贸格局发展,关于国际经济秩序“从自由到公平”的转型叙事频繁出现在公共讨论与研究视野。基于补贴规制视角,文章探究国际经济秩序公平转型叙事如何展开、有何疏漏。相对于多边补贴纪律,新兴补贴规则更关注公平贸易与竞争公平。尽管转型叙事可在一定程度上解释补贴规制的理念发展与规则演进,自由与公平语境下补贴规制各有困境,对补贴规制的观察也折射出转型叙事疏漏之处:一则有混淆政策转型与秩序转型之嫌,二则忽视安全等价值的影响,三则对公平与自由的内在联结未予充分关注。国际经贸规则重构深化背景下,问题关键在于因应公平导向的国际经贸规则可能引致的不公平后果,强化国际经济治理中的价值协调与利益平衡。

关键词：国际经济法国际经济秩序自由主义公平主义补贴规制

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乳腺光声成像进展

中国激光 2024年第9期51卷 29-41页

作者：黄可尔张良林励浙江大学生物医学工程与仪器科学学院浙江杭州310027

乳腺癌早期筛查、精准诊断、有效治疗是提高患者生存率的重要因素,而影像学是筛查、诊断、治疗评估的主要手段。基于现有的影像技术,乳腺临床诊治流程虽然已逐步规范化,但在高效灵敏筛查、无创精准诊断以及治疗监测评估等方面仍存在核... 详细信息

乳腺癌早期筛查、精准诊断、有效治疗是提高患者生存率的重要因素,而影像学是筛查、诊断、治疗评估的主要手段。基于现有的影像技术,乳腺临床诊治流程虽然已逐步规范化,但在高效灵敏筛查、无创精准诊断以及治疗监测评估等方面仍存在核心局限。例如,传统的医学影像技术存在诊断特异性低、成像速度慢、使用电离辐射或注射造影剂等局限,仍存在重大临床诉求。光声成像作为一项新兴的医学影像技术,可以与传统技术形成优势互补,提供快速(如10~15s完成全乳腺扫描)、高分辨率、信息丰富的医学影像。其光学对比度和声学分辨率使之具备揭示肿瘤微环境结构、功能、分子细节特征的能力。本文简述了光声成像的技术原理和主要设计形态,概述并评价了乳腺肿瘤筛查、诊断和治疗评估领域的代表性光声成像研究。最后讨论了光声成像在乳腺临床上的应用前景,其有望成为继钼靶、超声、核磁共振之后的“第四大”乳腺成像技术。

关键词：医用光学光声成像乳腺肿瘤微环境乳腺癌筛查早期精准诊断新辅助化疗评估肿瘤切缘检测