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Communications in Theoretical Physics 2024年第1期76卷 76-81页

作者： Cheng xu Zhen-hao Yang Xiao-Mei Kuang Rui-hong Yue Center for Gravitation and Cosmology College of Physical Science and TechnologyYangzhou UniversityYangzhou225009China

The scalar-free black hole could be unstable against the scalar field perturbation when it is coupled to a Gauss–Bonnet(GB)invariant in a special *** is known that the tachyonic instability in this scenario is triggered by the sufficiently strong GB *** this paper,we focus on the time domain analysis of massive scalar field perturbation around the Schwarzschild de-Sitter black hole in Einstein-scalar–Gauss–Bonnet *** analyzing the scalar field propagation,we find that the scalar field will finally grow when the GB coupling is large *** could lead to the instability of the background black ***,we demonstrate how the mass of the scalar field and the GB coupling strength affect the onset of tachyonic instability.

关键词： black hole perturbation scalar-Einstein-Gauss-Bonnet gravity time domain evolution me

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Threshold of climate extremes that impact vegetation productivity over the Tibetan Plateau

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Science China Earth Sciences 2024年第6期67卷 1967-1977页

作者： Zhenggang PIAO Xiangyi LI hao xu Kai WANG Shuchang TANG Fei KAN Songbai hong College of Urban and Environmental Sciences Peking UniversityBeijing 100871China

Vegetation growth is adversely impacted by multiple climate extremes related to the water and thermal stress over the Tibetan Plateau(TP).However,it remains unknown at which stress level these climate extremes can trigger the abrupt shifts of vegetation response to climate extremes and result in the maximum vegetation response across *** fill this knowledge gap,we combined the hydrometeorological data and the satellite-derived vegetation index to detect two critical thresholds that determine the response of vegetation productivity to droughts,high-temperature extremes,and low-temperature extremes,respectively,during *** results show that the response of vegetation productivity to droughts rapidly increases once crossing -1.41±0.6 standard deviation(σ)below the normal conditions of soil *** crossing-2.98σ±0.9σ,vegetation productivity is maximum damaged by ***-temperature extremes,which have the two thresholds of 1.34σ±0.4σand 2.31σ±0.4σover TP,are suggested to trigger the strong response of vegetation productivity at a milder stress level than low-temperature extremes(two thresholds:-1.44σ±0.5σand-2.53σ±0.8σ).Moreover,we found the compounded effects of soil moisture deficit in reducing the threshold values of both high-and low-temperature *** on the derived thresholds of climate extremes that impact vegetation productivity,Earth System Models project that southwestern TP and part of the northeastern TP will become the hotspots with a high exposure risk to climate extremes by *** study deciphers the high-impact extreme climates using two important thresholds across TP,which advances the understanding of the vegetation response to different climate extremes and provides a paradigm for assessing the impacts of climate extremes on regional ecosystems.

关键词： Tibetan Plateau Climate extremes Thresholds Vegetation productivity

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Effect of solidification mode on microstructure evolution and properties of magnesium alloy with long-period stacking ordered phase

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Journal of Iron and Steel Research International 2024年第5期31卷 1127-1138页

作者： hao Li hong-mei Chen xu Zhang Qian-hao Zang Jing Zhang Di Feng Yan-xin Qiao Yu-hang Guo School of Materials Science and Engineering Jiangsu University of Science and TechnologyZhenjiang212100JiangsuChina School of Metallurgy and Materials Engineering Jiangsu University of Science and TechnologySuzhou215600JiangsuChina

The solidification methods of electromagnetic stirring(EMS)and non-electromagnetic stirring were employed to prepare Mg–6Gd–3Y–xZn–0.6Zr(x=1,1.5,2,3)*** evolution of alloy microstructures and the changes in properties were analyzed for different Zn *** has been observed that in alloys without electromagnetic stirring,as the Zn content increases,the alloy structure gradually *** primary second phase transitions from Mg5RE phase to long-period stacking ordered(LPSO)phase,resulting in improved hardness and *** alloys subjected to electromagnetic stirring,there is a relatively higher content of the second phase,primarily consisting of LPSO *** applying electromagnetic stirring,the quantity and the type of LPSO phase in the alloy *** alloy structure becomes more uniform with electromagnetic stirring,resulting in increased hardness and reduced hardness gradients within the *** mechanical properties of alloys with electromagnetic stirring are superior to those without electromagnetic stirring.

关键词： Rare earth magnesium alloy LPSO phase Electromagnetic stirring Casting Property

Rational design of metal selenides nanomaterials for alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries:current status and perspectives

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Rare Metals 2024年第5期43卷 1906-1931页

作者： Rui Sun Feng xu Cai-hong Wang Sheng-Jun Lu Yu-Fei Zhang hao-Sen Fan College of Materials Science and Metallurgy Engineering Guizhou UniversityGuiyang550025China School of Chemistry and Chemical Engineering Guangzhou UniversityGuangzhou510006China

Recently,metal selenides have obtained widespread attention as electrode materials for alkali(Li^(+)/Na^(+)/K^(+))batteries due to their promising theoretical capacity and ***,metal selenides,similar to metal oxides and sulfides,also suffer from severe volume explosion during repeated charge/discharge processes,which results in the structure collapse and the following pulverization of electrode ***,it leads to poor cycle stability and influencing their further *** order to solve these issues,some special strategies,including elemental doping,coupling with carbon materials,synthesis of the bimetal selenides with heterostructure,etc.,have been gradually applied to design novel electrode materials with outstanding electrochemical ***,the recent research progress on metal selenides as anodes for alkali ion batteries is summarized,including the regulation of crystal structure,synthesis strategies,modification methods,and electrochemical mechanisms and ***,the challenges of metal selenides and the perspective for future electrode material design are *** is hoped to pave a way for the development of metal selenide electrode materials for the potential applications for alkali metal ion(Li^(+)/Na^(+)/K^(+))batteries.

关键词： Rational design Metal selenides Nanostructure Li^(+) batteries Na^(+) batteries K^(+) batteries

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Coupled Cu doping and Z-scheme heterojunction for synergistically enhanced tetracycline photodegradation

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Nano Research 2024年第7期17卷 5937-5948页

作者： Huidong Shen Chunming Yang Song hong Leiduan hao Liang xu Alex W.Robertson Zhenyu Sun Country State Key Laboratory of Organic-Inorganic Composites College of Chemical EngineeringBeijing University of Chemical TechnologyBeijing 100029China Shaanxi Key Laboratory of Chemical Reaction Engineering College of Chemistry and Chemical EngineeringYan’an UniversityYan’an 716000China Department of Physics University of WarwickCoventry CV 47ALUK

Semiconductor-based photocatalysis by utilizing solar energy for sustainable organic pollutant elimination has been a promising tactic to alleviate environmental ***,the development of robust and efficient photocatalysts to degrade organic pollutants still faces major challenges because of insufficient charge *** we design and fabricate a heterojunction consisting of copper,carbon-modified TiO_(2),and sulfur-doped g-C_(3)N_(4)nanosheets(i.e.,S-C_(3)N_(4)/Cu/C-TiO_(2)).The heterostructure affords a remarkable synergistic photocatalysis for tetracycline hydrochloride degradation,achieving an 82.6%removal efficiency within 30 min under visible light irradiation,about 15.4 and 7.3 times higher than that of S-C_(3)N_(4)and C-TiO_(2),*** superior performance is attributed to the synergy between Cu doping and the Z-scheme heterojunction,which not only enhances the interfacial electric field effect,facilitating charge separation,but also boosts the redox *** charge carrier transfer between Cu/C-TiO_(2)and S-C_(3)N_(4)follows a Z-scheme,as verified by trapping experiments,electron spin-resonance spectroscopy,and density functional theory ***,the tetracycline hydrochloride degradation pathways are enunciated by liquid chromatograph mass spectrometry *** work provides an effective approach for constructing high-performance photocatalysts that have potential in environmental remediation.

关键词： photocatalysis Cu doping Z-scheme heterojunction electrons and holes separation tetracycline degradation

RGB oralscan video-based orthodontic treatment monitoring

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Science China(Information Sciences) 2024年第1期67卷 124-139页

作者： Yan TIAN Hanshi FU hao WANG Yuqi LIU Zhaocheng xu hong CHEN Jianyuan LI Ruili WANG School of Computer Science and Technology Zhejiang Gongshang University Shining3D Tech Co. Ltd. School of Information and Technology Monash University School of Mathematical and Computational Sciences Massey University Department of Stomatology Zhejiang Provincial People's HospitalHangzhou Medical College School of Computer and Computing Science Zhejiang University City College

Orthodontic treatment monitoring involves using current images and previous 3D models to estimate the relative position of individual teeth before and after orthodontic *** process differs from image-based object 6D pose estimation due to the gingiva deformation and varying pose offsets for each tooth during *** by the fact that the poses of molars remain relatively fixed in implicit orthodontics,we design an approach that employs multiview pose evaluation and bidirectional temporal propagation for jaw pose estimation and then employs an iteration-based method for tooth *** handle changes in tooth appearance or location with weak texture across frames,we also introduce an instance propagation module that leverages positional and semantic information to explore instance relations in the temporal *** evaluated the performance of our approach using both the Shining3D tooth pose dataset and the Aoralscan3 tooth registration *** experimental results demonstrate remarkable accuracy improvements compared with existing methods.

关键词： digital dentistry object 6D pose estimation deep learning computer vision

Discovery of Partial Differential Equations from Highly Noisy and Sparse Data with Physics-Informed Information Criterion

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Research 2024年第1期2023卷 247-259页

作者： hao xu Junsheng Zeng Dongxiao Zhang BIC-ESAT EREand SKLTCSCollege of EngineeringPeking UniversityBeijing 100871P.R.China Institute of Applied Physics and Computational Mathematics Beijing 100088P.R.China Eastern Institute for Advanced Study Eastern Institute of TechnologyNingbo 315200ZhejiangP.R.China National Center for Applied Mathematics Shenzhen(NCAMS) Southern University of Science and TechnologyShenzhen 518055GuangdongP.R.China Department of Mathematics and Theories Peng Cheng LaboratoryShenzhen 518000GuangdongP.R.China

Data-driven discovery of partial differential equations(PDEs)has recently made tremendous progress,and many canonical PDEs have been discovered successfully for proof of ***,determining the most proper PDE without prior references remains challenging in terms of practical *** this work,a physics-informed information criterion(PIC)is proposed to measure the parsimony and precision of the discovered PDE *** proposed PIC achieves satisfactory robustness to highly noisy and sparse data on 7 canonical PDEs from different physical scenes,which confirms its ability to handle difficult *** PIC is also employed to discover unrevealed macroscale governing equations from microscopic simulation data in an actual physical *** results show that the discovered macroscale PDE is precise and parsimonious and satisfies underlying symmetries,which facilitates understanding and simulation of the physical *** proposition of the PIC enables practical applications of PDE discovery in discovering unrevealed governing equations in broader physical scenes.

关键词： process canonical proof

Segregation of Mg-6Gd alloy under natural convection:From macro solute distribution to micro dendrite growth

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China Foundry 2024年第5期21卷 613-624页

作者： hong-xu Chen Ang Zhang hao Li Yu Gao Yu-hong Cui Guang-sheng Huang Bin Jiang Fu-sheng Pan National Engineering Research Center for Magnesium Alloys National Key Laboratory of Advanced Casting TechnologiesCollege of Materials Science and EngineeringChongqing UniversityChongqing 400044China

Segregation is a serious defect in alloy ingots which severely deteriorates materials *** segregation defect in Mg-6Gd alloy is studied by coupling macro thermal-solutal-convection transport and micro dendrite *** macroscopic fluid dynamics and mass transfer equations are resolved to forecast the segregation behavior under conditions of continuous temperature variation during the solidification *** numerical model is validated by testing double-diffusive natural convection in a closed square cavity.A phase field model is then applied to simulate the micro dendrite growth,using macro undercooling and liquid flow velocity as boundary *** show that the multiscale segregation behavior,including macro solute distribution and micro dendritic morphology,is strongly dependent on the temperature condition and the liquid convection,which provides guidance for reducing and eliminating the segregation defect.

关键词： magnesium alloy segregation numerical simulation phase-field simulation multiscale

Decomposition of pre-existing Au–P clusters induced in situ a-Fe grains uniformization in Fe–P-based nanocrystalline alloys

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Rare Metals 2024年第10期43卷 5242-5255页

作者： Min-hao Han Cheng Sun Guo-Guo Xi Yang Meng Qiang Luo xue-Qian Yu Wen-Feng Zhang hao Liu hong-Jie xu Tao Zhang Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and EngineeringBeihang University Laboratory of Functional Fiber Materials Institute of Bast Fiber CropsChinese Academy of Agricultural Science School of Materials Science and Engineering Jiangsu Key Laboratory for Advanced Metallic MaterialsSoutheast University Institute for Advanced Materials North China Electric Power University Center for Advanced Analysis and Computational Science Zhengzhou University

In Fe-based amorphous-/nanocrystalline ribbons,the uniformization and refinement of a-Fe grains are key aspects for optimizing their soft magnetic and mechanical ***,the Fe–P–C–B nanocrystalline alloy system was selected for *** produced as-spun ribbons with pre-existing nanocrystals through melt-quenching and then obtained a well-distributed a-Fe nanocrystalline structure through annealing below the first crystallization onset temperature （633 K）resulting in excellent magnetic properties (saturation magnetization of 1.65 T and coercivity of 1.6 A·m-1)ultra-wide annealing temperature window （from 613 to 733 K）,and extremely high annealing stability （up to 480 min at 633 K）.Furthermore,we propose a new in situ two-step mechanism for the uniformization of a-Fe nanocrystals,which is separately induced by the decomposition of the Au–P clusters and the pre-existing a-Fe nanocrystals during *** work underscores the crucial significance of micro-alloying via metastable clusters primarily influenced by metal-phosphide interactions in the process of refining a-Fe ***,i introduces a new principle for optimizing the comprehensive properties of Fe-based amorphous/nanocrystalline alloys.

关键词： Fe-based nanocrystalline alloys In-situ nano-crystallization Micro-alloying Soft magnetic property

pH- and near-infrared light-responsive,biomimetic hydrogels from aqueous dispersions of carbon nanotubes

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Nano Research 2024年第4期17卷 3120-3129页

作者： Lulin Hu Xinxin Yu Jingcheng hao Lu xu Shandong Laboratory of Yantai Advanced Materials and Green Manufacturing Yantai 264000China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China Yantai Center for Food and Drug Control Yantai 264000China Key Laboratory of Colloid and Interface Chemistry&Key Laboratory of Special Aggregated Materials Shandong UniversityJinan 250100China

Owing to their low flexibility,poor processability and a lack of responsiveness,inorganic materials are usually non-ideal for constructing a living ***,to date,lifelike materials with structural hierarchies and adaptive properties usually rely on light and soft organic molecules,although few exceptions have been acquired using two-dimensional(2D)inorganic ***,with a systematic study on the gelation behavior of carbon-based 0D quantum dots,1D nanotubes,and 3D fullerenes,we find that acidified 1D carbon nanotubes(CNTs)can serve as an alternative building block for fabricating purely inorganic biomimetic soft *** as-prepared CNT gels exhibit not only a pH-or photothermal-triggered mechanical and tribological adaptivity,which allows them to simulate the behavior of sea cucumbers,peacock mantis shrimps,and mammalian muscles or cortical bones,but also a unique damping property that is similar to spider’s cuticular *** high elasticity,effective lubrication,excellent biocompatibility,and controllable friction and wear also allow them to function as a new type of smart lubricants,whose tribological properties can be regulated either by its internal pH changes or spatiotemporally by near-infrared(NIR)light irradiations,free of any toxic and flammable base oils or additives.

关键词： biomimetic hydrogels carbon nanotubes(CNTs) mechanical and tribological adaptivity pH-and near-infrared(NIR)light responsiveness switchable lubrication