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Influence of introducing zr,Ti,Nb and Ce elements on externally solidified crystals and mechanical properties of high-pressure die-casting Al–Si alloy

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International journal of Minerals,Metallurgy and Materials 2025年第1期32卷 147-153页

作者： junjie li Wenbo Yu zhenyu Sun Weichen zheng liangwei zhang Yanling Xue Wenning liu Shoumei Xiong Center of Materials Science and Engineering School of Mechanical and Electronic Control EngineeringBeijing Jiaotong UniversityBeijing 100044China Traffic&Transportation Engineering Central South UniversityChangsha 410075China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China

High pressure die casting(HPDC)AlSi10Mn Mg alloy castings are widely used in the automobile *** can optimize the mechanical properties of castings through heat treatment,while the release of thermal stress arouses the deformation of large integrated ***,the development of non-heat treatment Al alloys is becoming the hot *** addition,HPDC contains externally solidified crystals(ESCs),which are detrimental to the mechanical properties of *** achieve high strength and toughness of non-heat treatment die-casting Al-Si alloy,we used AlSi9Mn alloy as matrix with the introduction of zr,Ti,Nb,and *** influences on ESCs and mechanical properties were systematically investigated through three-dimensional reconstruction and thermodynamic *** results reveal that the addition of Ti increased ESCs'size and porosity,while the introduction of Nb refined ESCs and decreased ***,large-sized Al_3(zr,Ti)phases formed and degraded the mechanical *** introduction of Ce resulted in the poisoning effect and reduced mechanical properties.

关键词： aluminium alloy high-pressure die-casting externally solidified crystals non-heat treatment

Surface deformation-dependent mechanical properties of bending nanowires:an ab initio core-shell model

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Applied Mathematics and Mechanics(English Edition) 2022年第2期43卷 219-232页

作者： Ye XIAO j.SHANG L.z.KOU Chun li School of Mechanics Civil Engineering and ArchitectureNorthwestern Polytechnical UniversityXi’an710072China MIIT Key Laboratory of Dynamics and Control of Complex Systems Northwestern Polytechnical UniversityXi’an710072China School of Mechanical Medical and Process EngineeringQueensland University of TechnologyBrisbaneQLD4000Australia

An ab initio core-shell model is proposed to evaluate the surface effect in bending nanowires,in which the elastic modulus depends on the surface relaxation and deformation induced by external *** using first-principles calculations based on the density functional theory(DFT),the surface and bulk properties are calculated for Ag,Pb,and Si *** obtained theoretical predictions of the effective Young’s modulus of nanowires agree well with the experimental data,which shows that the fixed-fixed nanowire is stiffened and the cantilevered nanowire is softened as the characteristic size of the cross section ***,the contrastive analysis on the two kinds of nanowires demonstrates that increasing the nanowire aspect ratio would enhance the surface *** present results could be helpful for understanding the size effect in nanowires and designing nanobeam-based devices in nanoelectromechanical systems(NEMSs).

关键词： surface effect density functional theory(DFT) surface relaxation surface stress nanowire

Storage time affects the level and diagnostic efficacy of plasma biomarkers for neurodegenerative diseases

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Neural Regeneration Research 2025年第8期20卷 2373-2381页

作者： lifang zhao Mingkai zhang Qimeng li Xuemin Wang jie Lu Ying Han Yanning Cai Department of Clinical Biobank Xuanwu HospitalCapital Medical UniversityBeijingChina Beijing Geriatric Medical Research Center BeijingChina Department of Neurology Xuanwu HospitalCapital Medical UniversityBeijingChina Department of Radiology and Nuclear Medicine Xuanwu HospitalCapital Medical UniversityBeijingChina Beijing Key Laboratory of Magnetic Resonance Imaging and Brain Informatics BeijingChina Key Laboratory of Neurodegenerative diseases Ministry of EducationBeijingChina School of Biomedical Engineering Hainan UniversityHaikouHainan ProvinceChina Center of Alzheimer’s Disease Beijing Institute for Brain DisordersBeijingChina National Clinical Research Center for Geriatric Diseases BeijingChina Institute of Biomedical Engineering Shenzhen Bay LaboratoryGaoke Innovation CenterShenzhenGuangdong ProvinceChina Department of Neurobiology Xuanwu HospitalCapital Medical UniversityBeijingChina

Several promising plasma biomarker proteins,such as amyloid-β(Aβ),tau,neurofilament light chain,and glial fibrillary acidic protein,are widely used for the diagnosis of neurodegenerative ***,little is known about the long-term stability of these biomarker proteins in plasma samples stored at-80°*** aimed to explore how storage time would affect the diagnostic accuracy of these biomarkers using a large *** samples from 229 cognitively unimpaired individuals,encompassing healthy controls and those experiencing subjective cognitive decline,as well as 99 patients with cognitive impairment,comprising those with mild cognitive impairment and dementia,were acquired from the Sino Longitudinal Study on Cognitive Decline *** samples were stored at-80°C for up to 6 years before being used in this *** results showed that plasma levels of Aβ42,Aβ40,neurofilament light chain,and glial fibrillary acidic protein were not significantly correlated with sample storage ***,the level of total tau showed a negative correlation with sample storage ***,in individuals without cognitive impairment,plasma levels of total protein and tau phosphorylated protein threonine 181(p-tau181)also showed a negative correlation with sample storage *** was not observed in individuals with cognitive ***,we speculate that the diagnostic accuracy of plasma p-tau181 and the p-tau181 to total tau ratio may be influenced by sample storage ***,caution is advised when using these plasma biomarkers for the identification of neurodegenerative diseases,such as Alzheimer's ***,in cohort studies,it is important to consider the impact of storage time on the overall results.

关键词： Alzheimer’s disease amyloid-β diagnostic ability glial fibrillary acidic protein neurodegeneration neurofilament light chain plasma biomarkers single molecule array storage time tau

Correlation Between Local Atomic Symmetry and Mechanical Properties in Metallic Glasses

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journal of Materials Science & Technology 2014年第6期30卷 551-559页

作者： M.z.li Department of Physics Renmin University of China Beijing Key Laboratory of Opto-Electronic Functional Materials & Micro-nano Devices Renmin University of China

The local atomic symmetry was investigated and discussed for understanding mechanical, vibrational and dynamical properties in metallic glasses. Local five-fold symmetry was defined based on the ratio of pentagons to the total number of faces in a Voronoi cluster analyzed by Voronoi tessellation method. It is found that the plastic deformation prefer to be initiated in the regions with less degree of local five-fold symmetry （LFFS） and propagate gradually toward the region with more degree of LFFS. On the other hand, the local structures having less degree of LFFS contribute more to the soft low-frequency modes, and thus the so-called boson peak, while those with more degree of LFFS participate more in moderate- and high- frequency modes in metallic glasses. The relationship between local atomic symmetry and structural heterogeneity, mechanical heterogeneity, and glass transition was also discussed. It is shown that local atomic symmetry could be a general structural indicator in metallic liquids and glasses for better understanding the structure-property relationship in amorphous alloys.

关键词： Metallic glasses Atomic symmetry Deformation Molecular dynamics

Ab initio molecular dynamics study on the local structures in Ce_(70)Al_(30) and La_(70)Al_(30) metallic glasses

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Chinese Physics B 2018年第5期27卷 405-411页

作者： F X li j B Kong M z li Department of Physics Beijing Key Laboratory of Opto-electronic Functional Materials ＆ Micro-nano Devices Renmin University of China Beijing 100872 China

Ab initio molecular dynamics simulations were performed to investigate the effect of similar elements on the shortto medium-range atomic packing features in Ce70Al30 and La70Al30 glass-forming alloys. 4 f electrons of Ce element in Ce70Al30 alloy were properly treated in electronic calculations. The local atomic structures in both alloys are qualitatively similar. However, the local environments of Al atoms in Ce70Al30 alloy show fluctuation with temperature in the cooling process, which could result from 4 f electrons of Ce elements. Surprisingly, the medium-range atomic packing features of Al atoms in both MGs are quite different, although Ce and La elements are similar. These findings are useful for understanding the enhanced glass-forming ability by similar element substitution in RE-based MGs from a medium-range structure perspective.

关键词： rare earth-based metallic glasses medium-range order molecular dynamics simulation

A MONTE CARLO SIMULATION OF SECONDARY ELECTRON AND BACKSCATTERED ELECTRON IMAGES IN SCANNING ELECTRON MICROSCOPY

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Acta Metallurgica Sinica(English Letters) 2005年第3期18卷 351-355页

作者： H.M.li z.j.Ding HefeiNationalLaboratoryforPhysicalSciencesatMicroscaleandDepartmentofPhysics UniversityofScienceandTechnologyofChinaHefei230026China

A new parallel Monte Carlo simulation method of secondary electron (SE) and back scattered electron images (BSE) of scanning electron microscopy (SEM) for a com plex geometric structure has been developed. This paper describes briefly the si mulation method and the modification to the conventional sampling method for the step length. Example simulation results have been obtained for several artifici al structures.

关键词： Monte Carlo SEM secondary electrons backscattered electrons,

Industrial solid wastes to environmental protection materials for removal of gaseous pollutants:A review

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Green Energy & Environment 2025年第1期10卷 34-83页

作者： jiacheng Bao Xin Sun Ping Ning Kai li jie Yang Fei Wang Lei Shi Maohong Fan Faculty of Environmental Science and Engineering Kunming University of Science and TechnologyKunming650500China College of Engineering and Physical Sciences and School of Energy ResourcesUniversity of WyomingLaramieWY82071USA College of Engineering Georgia Institute of TechnologyAtlantaGA30332USA

The application of industrial solid wastes as environmentally functional materials for air pollutants control has gained much attention in recent years due to its potential to reduce air pollution in a cost-effective *** this review,we investigate the development of industrialwaste-based functional materials for various gas pollutant removal and consider the relevant reaction mechanism according to different types of industrial solid *** see a recent effort towards achieving high-performance environmental functional materials via chemical or physical modification,in which the active components,pore size,and phase structure can be *** review will discuss the potential of using industrial solid wastes,these modified materials,or synthesized materials from raw waste precursors for the removal of air pollutants,including SO_(2),NO_(x),Hg^(0),H_(2)S,VOCs,and CO_(2).The challenges still need to be addressed to realize this potential and the prospects for future research *** suggestions for future directions include determining the optimal composition of these materials,calculating the real reaction rate and turnover frequency,developing effective treatment methods,and establishing chemical component databases of raw industrial solid waste for catalysts/adsorbent preparation.

关键词： Industrial solid waste Reaction mechanism Modification method Air pollutants

Unraveling post-growth mechanisms of monolayer CsPbBr3 nanocubes:Laser-enhanced transformations and cathodoluminescence-electron microscopy correlations

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journal of Energy Chemistry 2025年第1期100卷 146-156页

作者： Mingxing li Xiaoge Wang Xiaofan Cao zhiqun He Chunjun liang Mingxing Chen jing ju Fangtian You Key Laboratory of Luminescence and Optical Information Ministry of Education Institute of Optoelectronic Technology Beijing Jiaotong University Beijing National Laboratory for Molecular Sciences (BNLMS) College of Chemistry and Molecular Engineering Peking University

Lead-halide perovskite nanoparticles（LHP NPs） are highly promising materials for next-generation displays and solid-state lighting due to their exceptional optical properties. However, their inherent instability presents a significant challenge. Recent advances have demonstrated that optoelectronic devices based on monolayer nanoparticle films exhibit both high luminescence efficiency and long-term *** research demonstrates that mobility limitations and anisotropic alignments in CsPbBr3nanocube monolayer films are key to their stabilization, hindering spontaneous growth through face-to-face fusion and resulting in the formation of connecting necks in a diagonal direction. Introducing laser irradiation confirmed this by significantly accelerating nanocubes growth, increasing mobility, and enhancing local structural ordering, leading to larger and more regularly shaped nanosheets. Fourier transform infrared spectroscopy and energy dispersive spectroscopy line-scan analyses indicated that laser irradiation did not disrupt the ligand structure. Transmission electron microscopy and correlative cathodoluminescence electron microscopy revealed the effects of post-growth and heterogeneous structures, including enhanced luminescence and inhomogeneous intensity in the nanosheets. These findings deepen the understanding of the post-growth mechanism of monolayer nanoparticles and the structure-emission correlation and highlight the unique role of laser irradiation in directing the formation of well-defined and regular nanostructures.

关键词： Energy dispersive spectroscopy

High-energy-density lithium manganese iron phosphate for lithium-ion batteries: Progresses, challenges, and prospects

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journal of Energy Chemistry 2025年第1期100卷 1-17页

作者： Bokun zhang Xiaoyun Wang Shuai Wang Yan li libo Chen Handong jiao zhijing Yu jiguo Tu State Key Laboratory of Advanced Metallurgy University of Science and Technology Beijing Research Institute for Intelligent Wearable Systems The Hong Kong Polytechnic University Institute of Advanced Structure Technology Beijing Institute of Technology

The soaring demand for smart portable electronics and electric vehicles is propelling the advancements in high-energy–density lithium-ion *** manganese iron phosphate (liMnxFe1-xPO4) has garnered significant attention as a promising positive electrode material for lithium-ion batteries due to its advantages of low cost,high safety,long cycle life,high voltage,good high-temperature performance,and high energy *** liMnxFe1-xPO4has made significant breakthroughs in the past few decades,there are still facing great challenges in poor electronic conductivity and li-ion diffusion,manganese dissolution affecting battery cycling performance,as well as low tap *** review systematically summarizes the reaction mechanisms,various synthesis methods,and electrochemical properties of liMnxFe1-xPO4to analyze reaction processes accurately and guide material ***,the main challenges currently faced are concluded,and the corresponding various modification strategies are discussed to enhance the reaction kinetics and electrochemical performance of liMnxFe1-xPO4,including multi-scale particle regulation,heteroatom doping,surface coating,as well as microscopic morphology ***,in view of the current research challenges faced by intrinsic reaction processes,kinetics,and energy storage applications,the promising research directions are *** importantly,it is expected to provide key insights into the development of high-performance and stable liMnxFe1-xPO4materials,to achieve practical energy storage requirements.

关键词： Semiconductor doping