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Thermal properties and high-temperature ablation of high-entropy (Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) coating on graphite substrate

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Journal of Advanced Ceramics 2024年第8期13卷 1268-1281页

作者： Ana C.Feltrin daniel Hedman Farid Akhtar Division of Materials Science Lulea University of TechnologyLulea 97187Sweden Center for Multidimensional Carbon Materials(CMCM) Institute for Basic Science(IBS)Ulsan 44919Republic of Korea

An entropy-stabilized multicomponent ultrahigh-temperature ceramic(UHTC)coating,(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2),on a graphite substrate was in-situ sintered by spark plasma sintering(SPs)from constituent transition metal diboride ***(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) coating had a hardness of 31.2±2.1 GPa and resisted 36.9 GPa of stress before delamination,as observed at the *** temperature-dependent thermal properties of the multicomponent diboride(Ti_(0.25)V_(0.25)Zr_(0.25)Hf_(0.25))B_(2) were obtained by molecular dynamics(MD)simulations driven by a machine learning force field(MLFF)trained on density functional theory(DFT)*** thermal conductivity,density,heat capacity,and coefficient of thermal expansion obtained by the MD simulations were used in time-dependent thermal stress finite element model(FEM)*** low thermal conductivity(<6.52 W·m^(-1)·K^(-1))of the multicomponent diboride coupled with its similar coefficient of thermal expansion to that of graphite indicated that stresses of less than 10 GPa were generated at the interface at high temperatures,and therefore,the coating was mechanically resistant to the thermal stress induced during *** experiments at 220℃ showed that the multicomponent diboride coating was resistant to thermal stresses with no visible cracking or *** ablation mechanisms were mechanical denudation and evaporation of B_(2)O_(5) and light V-Ti oxides,which caused a decrease in the mass and thickness of the coating and resulted in mass and linear ablation rates of-0.51 mg·s^(-1) and -1.38μm·s^(-1),respectively,after 60 *** findings demonstrated the thermal and mechanical stability of multicomponent entropy-stabilized diborides as coatings for carbon materials in engineering components under extreme environments.

关键词： entropy-stabilized diborides ultrahigh temperature ceramics molecular dynamics(MD)simulations density functional theory(DFT) ablation properties

Probabilistic analysis of tunnel face seismic stability in layered rock masses using Polynomial Chaos Kriging metamodel

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第7期16卷 2678-2693页

作者： Jianhong Man Tingting Zhang Hongwei Huang daniel Dias Department of Geotechnical Engineering Key Laboratory of Geotechnical and Underground Engineering of Ministry of EducationCollege of Civil EngineeringTongji UniversityShanghai200092China Grenoble Alpes 3SR LabCNRS UMR 5521Grenoble38000France

Face stability is an essential issue in tunnel design and *** rock masses are typical and ubiquitous;uncertainties in rock properties always *** view of this,a comprehensive method,which combines the Upper bound Limit analysis of Tunnel face stability,the Polynomial Chaos Kriging,the Monte-Carlo Simulation and Analysis of Covariance method(ULT-PCK-MA),is proposed to investigate the seismic stability of tunnel faces.A two-dimensional analytical model of ULT is developed to evaluate the virtual support force based on the upper bound limit *** efficient probabilistic analysis method PCK-MA based on the adaptive Polynomial Chaos Kriging metamodel is then implemented to investigate the parameter uncertainty *** input parameters,including geological strength indices,uniaxial compressive strengths and constants for three rock formations,and the horizontal seismic coefficients,are treated as random *** effects of these parameter uncertainties on the failure probability and sensitivity indices are *** addition,the effects of weak layer position,the middle layer thickness and quality,the tunnel diameter,the parameters correlation,and the seismic loadings are investigated,*** results show that the layer distributions significantly influence the tunnel face probabilistic stability,particularly when the weak rock is present in the bottom *** efficiency of the proposed ULT-PCK-MA is validated,which is expected to facilitate the engineering design and construction.

关键词： Tunnel face stability Layered rock masses Polynomial Chaos Kriging(PCK) Sensitivity index Seismic loadings

Deterministic and probabilistic analysis of great-depth braced excavations:A 32 m excavation case study in Paris

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第5期16卷 1505-1521页

作者： Tingting Zhang Julien Baroth daniel Dias Khadija Nejjar Université Grenoble Alpes CNRSGrenoble INP3SRGrenoble38000France Antea Group Antony92160France School of Automotive and Transportation Engineering Hefei University of TechnologyHefei23009China Terrasol 42-52 Quai de la RapéeParis75012France

The Fort d’Issy-Vanves-Clamart(FIVC)braced excavation in France is analyzed to provide insights into the geotechnical serviceability assessment of excavations at great depth within deterministic and probabilistic *** FIVC excavation is excavated at 32 m below the ground surface in Parisian sedimentary basin and a plane-strain finite element analysis is implemented to examine the wall deflections and ground surface settlements.A stochastic finite element method based on the polynomial chaos Kriging metamodel(MSFEM)is then proposed for the probabilistic *** with field measurements and former studies are carried *** academic cases are then conducted to investigate the great-depth excavation stability regarding the maximum horizontal wall deflection and maximum ground surface *** results indicate that the proposed MSFEM is effective for probabilistic analyses and can provide useful insights for the excavation design and construction.A sensitivity analysis for seven considered random parameters is then *** soil friction angle at the excavation bottom layer is the most significant one for *** soil-wall interaction effects on the excavation stability are also given.

关键词： Braced deep excavation Soil-wall interaction Stochastic finite element method Horizontal wall deflection Settlement Failure probability

Transfer of Highest Weight Modules and Small Unipotent Representations

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Acta Mathematica Sinica,English Series 2024年第3期40卷 772-791页

作者： Hai An HE Jing Song HUANG Kayue daniel WONG Department of Mathematics College of SciencesShanghai UniversityShanghai 200444P.R.China Newtouch Center for Mathematics of Shanghai University Shanghai 200444P.R.China Mathematics Research Center School of Science and EngineeringThe Chinese University of Hong KongShenzhen 518172P.R.China

We study the transfer between small special unipotent representations for all equal rank real forms of type E_(6) and E_(7). As a consequence, one can verify these modules are unitarity using the results of Wallach an... 详细信息

关键词： Unipotent representations Wallach representations Transfer of unitary modules

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Flame Synthesis of Zr/ZSM-5 Catalysts with Tunable Acidity for the Oxidative Dehydrogenation of Propane to Propene

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Journal of Thermal Science 2024年第1期33卷 268-283页

作者： daniel Samuel FONZEU MONGUEN Cedric Karel WU Lingnan TIAN Zhenyu Institute of Engineering Thermophysics Chinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China

Tuning the surface acidity of ZSM-5 catalyst is essential to achieve desired propene selectivity and *** several ratios of Zr were utilized to modify ZSM-5 via flame spray pyrolysis technique coupled with a pulse spray evaporation *** interaction between Zr and ZSM-5 in the flame influenced the physicochemical and acidity properties of the Zr/*** increasing Zr ratio in ZSM-5 shows coated layers of irregular nano-sized Zr with an increase in crystallite sizes due to the synergetic effect between Zr and *** surface chemical analysis revealed increased lattice oxygen on the Zr modified ZSM-5(1:4) sample compared to other *** acidity analysis revealed the Lewis and Br?nsted acid distribution in the weak and medium acid sites on the catalyst ***,the increase in Zr loading decreased the concentration of Br?nsted acid sites and tuned the catalyst surface to more Lewis acidity,promoting propene selectivity and hindering the over-oxidation of *** modified ZSM-5 catalysts were examined in a fixed bed reactor within 300℃-700℃ at a gas hourly space velocity(GHSV) of 6000 mL·g(catalysts)^(-1)·h^(-1) for the oxidative dehydrogenation of propane(ODHP) to *** the catalysts,Zr/ZSM-5(1:4) exhibited the best propene yield, with 57.19% propane conversion and 75.54% selectivity to propene and the highest *** work provides a promising strategy for tuning the surface acidity of ZSM-5 with Zr for ODHP applications.

关键词： flame synthesis Zr modified ZSM-5 catalyst ODHP surface acidity lattice oxygen

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Exploring visual quality of multidimensional time series projections

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Visual Informatics 2024年第2期8卷 27-42页

作者： Tanja Munz-Körner daniel Weiskopf Visualization Research Center(VISUS) University of StuttgartAllmandring 19StuttgartGermany

Dimensionality reduction is often used to project time series data from multidimensional to two-dimensional space to generate visual representations of the temporal *** this context,we address the problem of multidimensional time series visualization by presenting a new method to show and handle projection errors introduced by dimensionality reduction techniques on multidimensional temporal *** visualization,subsequent time instances are rendered as dots that are connected by lines or curves to indicate the temporal ***,inevitable projection artifacts may lead to poor visualization quality and misinterpretation of the temporal *** projected data points,inaccurate variations in the distances between projected time instances,and intersections of connecting lines could lead to wrong assumptions about the original *** adapt local and global quality metrics to measure the visual quality along the projected time series,and we introduce a model to assess the projection error at intersecting *** serve as a basis for our new uncertainty visualization techniques that use different visual encodings and interactions to indicate,communicate,and work with the visualization uncertainty from projection errors and artifacts along the timeline of data points,their connections,and *** approach is agnostic to the projection method and works for linear and non-linear dimensionality reduction methods alike.

关键词： Time series Multidimensional data Dimensionality reduction Projection errors Visual quality Visual analytics

Machine learning based state-of-charge prediction of electrochemical green hydrogen production:Zink-Zwischenschritt-Elektrolyseur(ZZE)

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Energy and AI 2024年第2期16卷 269-276页

作者： daniel Vila Elisabeth Hornberger Christina Toigo STOFF2 GmbH–Gebäude H/Flughafen Tegel 1 13405 BerlinGermany University of Applied Sciences Upper Austria Stelzhamerstraße 23A-4600 WelsAustria Centre for Economic Research on Inclusivity and Sustainability at the University of Galway University RoadGalwayIreland

The intermittency of renewable energy is a key limiting factor for the successful decarbonization of both energy producing and consuming sectors. Green hydrogen has the potential to act as the central energy vector connecting hard-to-abate sectors to renewable power. However, combining energy storage and conversion for a holistic electrolyzer system remains challenging. Here, we show the innovative Zink-Zwischenschritt Elektrolyseur (ZZE), or Zinc Intermediate step Electrolyzer in English, that temporarily decouples the water splitting reaction and uses zinc to store electrical energy in chemical form. To perform optimal operation of a ZZE system, machine learning models were applied to predict the state of charge of a lab scale ZZE system. Using various models, we were able to determine the effectiveness of the prediction and contrast it to state of charge predictions of other energy storage systems. We show that a bi-directional long short-term memory neural network approach has the lowest error within the testing environment. This work serves to perform further ZZE development as well as state of charge prediction for other novel energy storage technologies.

关键词： Electrolyzer Battery ZZE Energy storage State of charge Machine learning Sequence-to-sequence model

Rapid growth in a large Cambrian apex predator

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National Science Review 2024年第3期11卷 128-136页

作者：吴雨 Stephen Pates daniel Pauly 张兴亮傅东静 State Key Laboratory of Continental Dynamics and Shaanxi Key Laboratory of Early Life and Environment Department of Geology Northwest University Department of Zoology University of Cambridge Institute for the Oceans and Fisheries University of British Columbia Nanjing Institute of Geology and Palaeontology Chinese Academy of Sciences

Despite the importance of ontogenetic data on early diverging euarthropods to our understanding of the ecology and evolution of past life, the data are distinctly lacking, as reconstructing life histories of fossil animals is often challenging. Here we report the growth trajectory of frontal appendages of the apex predator Amplectobelua symbrachiata, one of the most common radiodont arthropods from the early Cambrian Chengjiang biota(c. 520 Ma) of China. Analysis of 432 specimens(9.1–137.1 mm length; 1.3–25.6 mm height) reveals that appendages grew isometrically, with an estimated maximum size of the whole animal of c. 90 cm. Individuals grew rapidly compared to extant arthropods, as assessed using the electronic length-frequency analysis(ELEFAN) approach. Therefore, we show that the Cambrian apex predator A. symbrachiata was an extremely fast-growing arthropod, with an unusual life history strategy that formed as part of the escalatory ‘arms race’ that shaped the Cambrian explosion over 500 Ma.

关键词： stem-group Euarthropoda Radiodonta post-embryonic development growth dynamics Cambrian Explosion

Iron regulatory protein 1: the deadly switch of ferroptosis

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Neural Regeneration Research 2024年第3期19卷 477-478页

作者： daniel A.Bórquez Pamela J.Urrutia Center for Biomedical Research Faculty of MedicineUniversidad Diego PortalesSantiagoChile Institute of Nutrition&Food Technology(INTA) Universidad de ChileSantiagoChile Geroscience Center for Brain Health and Metabolism SantiagoChile

Ferroptosis,an iron-dependent cell death:Ferroptosis is a type of regulated necrosis,characterized by redox-active iron accumulation and increased free radical production derived by Fenton chemistry,that triggers oxidation of polyunsaturated fatty acids in phospholipids,loss of cellular membranes integrity,and leakage of intracellular contents.

关键词： integrity switch Iron

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