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Relationship between the unique microstructures and behaviors of high-entropy alloys

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International Journal of Minerals,Metallurgy and Materials 2024年第6期31卷 1350-1363页

作者： Yaqi Wu Peter k.iaw Ruixuan Li Weiran Zhang Guihong Geng Xuehui yan Guiqun Liu Yong Zhang State k.y Laboratory for Advanced Metals and Materials University of Science and Technology BeijingBeijing 100083China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA Xi’an Rare Metal Materials Institute Co.Ltd. Xi’an 710016China School of Materials Science and Engineering North Minzu UniversityYinchuan 750030China GRIMAT Engineering Institute Co. Ltd.Beijing 101407China

High-entropy alloys(HEAs),which were introduced as a pioneering concept in 2004,have captured the k.en interest of nu-merous ***,in this context,can be perceived as representing disorder and *** contrast,elemental composi-tions within alloy systems occupy specific structural sites in space,a concept referred to as *** accordance with Shannon entropy,structure is analogous to ***,the arrangement of atoms within a material,termed its structure,plays a pivotal role in dictating its *** addition to expanding the array of options for alloy composites,HEAs afford ample opportunities for diverse structural *** profound influence of distinct structural features on the exceptional behaviors of alloys is underscored by numer-ous *** features include remark.bly high fracture strength with excellent ductility,antiballistic capability,exceptional radi-ation resistance,and corrosion *** this paper,we delve into various unique material structures and properties while elucidating the intricate relationship between structure and performance.

关键词： high-entropy alloys unique microstructure special properties alloy design

Extractable and k.rogen-bound hopanoids from typical Eocene oil shales in China

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Energy Geoscience 2024年第2期5卷 171-179页

作者： Changbo Zhai Zhirong Zhang John k.Volk.an Hong Lu yan'e Chen SINOPEC k.y Laboratory of Petroleum Accumulation Mechanisms Wuxi Institute of Petroleum GeologySINOPEC2060 Lihu RoadWuxiJiangsu213126China SINOPEC Petroleum Exploration and Production Research Institute 31 Xueyuan RoadBeijing100083China State k.y Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of ScienceGuangzhou510640GuangdongChina

This study conducted a comparative analysis of extractable hopanoid hydrocarbons and those released via stepwise pyrolysis of typical Eocene immature oil shales in China,namely the Huadian,Maoming,and Fushun *** the Huadian and Maoming shales exhibit immature indicators in extractable and k.rogen-bound hopanoids(notably,high abundance of C_(29)to C_(32)17β,21β-hopanes and unsaturated hopenes).In contrast,the Fushun oil shale's hopanoids from extracts and pyrolyzates suggest a higher maturity *** absence of neohopenes in the pyrolyzates of the shales underpins that the k.rogenbound hopanoid sk.letons resist ***,the Huadian oil shale's asymmetric distribution of C_(29)and C_(30)hopenes and neohopenes hints at the presence of an additional *** unsaturated hopenes,such as hop-20(21)-enes,identified in pyrolyzates of the three k.rogens at various pyrolysis temperatures,reveal the occurrence of double bonds in k.rogen-bound hopanoid sk.letons without methyl *** absence of hop-20-(21)-ene in extracts suggests that it might act as an intermediate of these novel hopenes during the epimerization of hopanoid sk.letons within *** extractable and pyrolytic hopanoids'stereochemical alignment indicates that epimerization may occur in both ring systems and alk.l side chains of k.rogen-bound hopanoid *** stepwise pyrolysis proves to be a quick.screening method for geological hopanoids without causing any significant alteration to the original sk.letons even when crack.ng multiple covalent bonds is necessary.

关键词： Hopanoid Hopane Hopene Neohopene Stepwise pyrolysis k.rogen Eocene oil shale

Approaching the theoretical capacity of TiO_(2) anode in a photorechargeable lithium-ion battery

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Nano Research 2024年第4期17卷 2655-2662页

作者： Wen yan Jie Wang Qing Hu Jingjing Fu Mohamed k.Albolk.ny Tian Zhang Xiao Lu Fei Ye Bo Liu School of Chemistry and Materials Science University of Science and Technology of ChinaHefei 230026China

New generation of lithium-ion batteries(LIBs)integrating solar energy conversion and storage is emerging,as they could solve the fluctuation problem in the utilization of solar ***-rechargeable lithium-ion batteries(PR-LIBs)are ideal devices for such target,in which solar energy is converted into electricity and stored in *** order to achieve the high performance of PR-LIB,it is crucial to develop dual-function electrode materials that can synergistically capture solar energy and store ***,we present photo-rechargeable lithium-ion batteries using defective black.TiO_(2) as photoanode prepared by lithium *** photoanode exhibits excellent photo response in full solar spectrum with a capacity enhancement of 46.4%under illumination,corresponding to the energy conversion efficiency of 4.4%at the current density of 1 A·g^(-1).When illumination is applied at 20 mA·g^(-1),the battery capacity increases from~230 in dark.to~349 mAh·g^(-1) at the first cycle,and then stabilizes at 310 mAh·g^(-1),approaching the theoretical value of 335 mAh·g^(-1) of TiO_(2) electrode *** finding provides thoughts for break.ng the capacity limitations in TiO_(2) and paves the way for powering LIBs by solar illumination.

关键词： photo-rechargeable lithium-ion batteries photoanode defective TiO_(2)(D-TiO_(2))

Enhanced activity and durability of FeCoCrMoCBY nanoglass in acidic hydrogen evolution reaction

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Journal of Materials Science & Technology 2024年第3期170卷 212-220页

作者： Mengyang yan Shuangqin Chen Shangshu Wu Xuechun Zhou Shu Fu Di Wang Christian k.bel Horst Hahn Si Lan Tao Feng Herbert Gleiter Institute of Nanoscience School of Material Science and EngineeringNanjing University of Science and TechnologyNanjing 210094China Institute of Nanotechnology Karlsruhe Institute of TechnologyKarlsruhe 76021Germany

In the present work.a multi-element nanoglass(m-NG)of FeCoCrMoCBY is obtained first time by the laser ablation combined with inert gas condensation(laser-IGC)*** with the conventional rapid-quenched metallic glass(MG)with identical composition,the Fe-based m-NG demonstrates a superior performance as a self-supported electrocatalyst for hydrogen evolution reaction(HER)in acidic *** enhanced HER activity of m-NG is proposed to be closely related to its high en-ergy states,which is originated from the unique inhomogeneous nanostructures with a high density of low-coordinated ***,the Fe-based m-NG exhibits an outstanding comprehensive catalytic performance even beyond the commercial Pt/C catalyst in long-term test due to its self-optimization *** work.not only opens the way to the preparation of m-NGs by the novel laser-IGC technique,but also mak.s a great contribution to developing low-cost,high-efficient,and super-durable HER electrocat-alysts in acidic environment.

关键词： Nanoglass Inert gas condensations High energy states Hydrogen evolution reactions

Fully Nonlinear Equations of k.ylov Type on Riemannian Manifolds with Totally Geodesic Boundary

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Acta Mathematica Sinica,English Series 2024年第5期40卷 1293-1307页

作者： Li CHEN yan HE Faculty of Mathematics and Statistics Hubei Key Laboratory of Applied MathematicsHubei UniversityWuhan 430000P.R.China

In this paper,we study fully nonlinear equations of k.ylov type in conformal geometry on compact smooth Riemannian manifolds with totally geodesic *** prove the a priori estimates for solutions to these equations and ... 详细信息

关键词： The modified Schouten tensor k.convex Hessian type equation

A deoxidation thermodynamic model for 304 stainless steel considering multiple-components coupled reactions

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Journal of Iron and Steel Research(International) 2024年第1期31卷 74-91页

作者： yan yan Guang-hao Shang Li-ping Zhang Shao-ying Li Han-jie Guo School of Metallurgical and Ecological Engineering University of Science and Technology BeijingBeijing100083China Beijing k.y Laboratory of Special Melting and Preparation of High-End Metal Materials Beijing100083China Henan Jinhui Stainless Steel Industry Group Co. Ltd.Xuchang461500HenanChina Changge Jinhui Recycling Metal R&D Co. Ltd.Xuchang461500HenanChina

A thermodynamic model for predicting the equilibrium oxygens of 304 stainless steel was developed based on the theory of slag-steel equilibrium,the law of mass conservation,and the ion and molecule coexistence *** the developed model,the Fe-Cr-Mn-Si-Al-S-O-melts reaction system and CaO-MgO-CaF_(2)-FeO-MnO-Al_(2)O_(3)-SiO_(2)-Cr2O_(3)slags were *** oxygen contents calculated by the model are in good agreement with experimental results and reference *** equilibrium oxygen contents in 304 stainless steel mainly decrease with increasing binary basicity(w(CaO)/w(SiO_(2)),where w(i)is the mass percentage of component i)and decreasing *** binary basicity at 2.0 while maintaining temperatures lower than 1823 k.will k.ep the oxygen contents in the 304 stainless steel lower than 15×10^(-6).The equilibrium oxygen contents may also be decreased with increasing content of MgO in slags,which is more significant at lower binary ***,a small amount of FeO,MnO,and Al_(2)O_(3)(about 0-2.5 wt.%)in slags has little effect on equilibrium oxygen ***,it is found that the[C]-[O]reaction may occur during refining process but will not significantly affect the equilibrium oxygen contents.

关键词： Complex deoxidation Thermodynamic model Ion and molecule coexistence theory 304 stainless steel Slag-steel reaction

Clustering for Bivariate Functional Data

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 613-629页

作者： Shi-yun CAO yan-qiu ZHOU yan-ling WAN Tao ZHANG School of Science Guangxi University of Science and TechnologyLiuzhou 545006China School of Marxism Guangxi University of Science and TechnologyLiuzhou 545006China k.y Laboratory of Intelligent Information Processing and Graph Processing Guangxi University of Science and TechnologyLiuzhou 545006China

In this paper,we consider the clustering of bivariate functional data where each random surface consists of a set of curves recorded repeatedly for each *** k.centres surface clustering method based on marginal functional principal component analysis is proposed for the bivariate functional data,and a novel clustering criterion is presented where both the random surface and its partial derivative function in two directions are *** addition,we also consider two other clustering methods,k.centres surface clustering methods based on product functional principal component analysis or double functional principal component *** results indicate that the proposed methods have a nice performance in terms of both the correct classification rate and the adjusted rand *** approaches are further illustrated through empirical analysis of human mortality data.

关键词： bivariate functional data -centres surface clustering functional principal component analysis partial derivative function

MIXED DISCONTINUOUS GALERk.N METHOD FOR QUASI-NEWTONIAN STOk.S FLOWS

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Journal of Computational Mathematics 2024年第3期42卷 885-910页

作者： yanxia Qian Fei Wang Wenjing yan School of Mathematics and Statistics Xi'an Jiaotong UniversityXi'an 710049China School of Mathematics and Statistics&State k.y Laboratory of Multiphase Flow in Power Engineering Xi'an Jiaotong UniversityXi'an 710049China

In this paper,we introduce and analyze an augmented mixed discontinuous Galerk.n(MDG)method for a class of quasi-Newtonian Stok.s *** the mixed formulation,the unk.owns are strain rate,stress and velocity,which are approximated by a discontinuous piecewise polynomial triplet ■for k.***,the discontinuous piecewise polynomial function spaces for the field of strain rate and the stress field are designed to be *** addition,the pressure is easily recovered through simple *** the benefit of the analysis,we enrich the MDG scheme with the constitutive equation relating the stress and the strain rate,so that the well-posedness of the augmented formulation is obtained by a nonlinear functional *** k.0,we get the optimal convergence order for the stress in brok.n ■(div)-norm and velocity in L^(2)-***,the error estimates of the strain rate and the stress in-norm,and the pressure in L^(2)-norm are optimal under certain ***,several numerical examples are given to show the performance of the augmented MDG method and verify the theoretical *** evidence is provided to show that the orders of convergence are sharp.

关键词： Quasi-Newtonian fows Mixed discontinuous Galerk.n method Symmetric strain rate Symmetric stress Optimal convergence orders

Achieving strength–ductility synergy in novel paramagnetic Fe-based medium-entropy alloys through deep cryogenic deformation

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Rare Metals 2024年第9期43卷 4493-4507页

作者： Hu-Wen Ma yan-Chun Zhao Li Feng Tian-Zeng Liu Zhi-Qi Yu Bo Jin Wang-Chun Duan Peter k.Liaw Dong Ma State k.y Laboratory of Advanced Processing and Recycling of Non-Ferrous Metals Lanzhou University of Technology Wenzhou Pump and Valve Engineering Research Institute Lanzhou University of Technology Iron and Steel Research Institute Jiuquan Iron and Steel Corporation Lanzhou Resources and Environment Voc-Tech University Department of Materials Science and Engineering The University of Tennessee Neutron Science Center Songshan Lake Materials Laboratory

Cryogenic pre-deformation treatment has been widely used to effectively improve the comprehensive mechanical properties of steels and novel metals. However,the dislocation evolution and phase transformation induced by different degrees of deep cryogenic deformation are not yet fully elucidated. In this study, the effects of multiple cryogenic pre-treatments on the mechanical properties and deformation mechanisms of a paramagnetic Fe63.3Mn14-Si9.1Cr9.8C3.8medium-entropy alloy（MEA） were investigated, leading to the discovery of a pretreated MEA that exhibits exceptional mechanical properties, including a fracture strength of 3.0 GPa, plastic strain of 26.1% and work.hardening index of 0.57. In addition, X-ray diffraction（XRD） and transmission electron microscopy（TEM）analyses revealed that multiple cryogenic pre-deformation treatments significantly increased the dislocation density of the MEA(from 9 × 1015to 4 × 1016m-2after three pretreatments), along with a transition in the dislocation type from predominantly edge dislocations to mixed dislocations（including screw-and edge-type dislocations）. Notably, this pretreated MEA retained its paramagnetic properties（μrk.ng fault energy of the MEA by a factor of approximately four(i.e., from 9.7 to2.6 m J·m-2), thereby activating the synergistic effects of transformation-induced plasticity, twinning-induced plasticity and dislocation strengthening mechanisms. These synergistic effects lead to simultaneous strength and ductility enhancement of the MEA.

关键词： Deep cryogenic transformation Dislocation evolution Iron-based medium-entropy alloys Phase transformation Stack.ng fault energy