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Non-monotonic temperature evolution of nonlocal structure–dynamics correlation in Cuzr glass-forming liquids

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Chinese Physics B 2021年第7期30卷 370-375页

作者： W J Jiang m z li Department of Physics and Beijing Key Laboratory of Opto-electronic Functional materials&micro-nano Devices Renmin University of ChinaBeijing 100872China

The structure–dynamics correlations in a nonlocal manner were investigated in Cuzr metallic glass-forming liquids via classical molecular dynamics simulations.A spatial coarse-graining approach was employed to incorporate the nonlocal structural information of given structural order parameters in the structure–dynamics *** is found that the correlation between structure order parameters and dynamics increases with increasing coarse-graining length and has a characteristic length ***,the characteristic correlation length exhibits a non-monotonic temperature evolution as temperature approaches glass transition temperature,which is not sensitive to the considered structure order *** results unveil a striking change in the structure–dynamics correlation,which involves no fitting theoretical *** findings provide new insight into the structure–dynamics correlation in glass transition.

关键词： metallic glass-forming liquid structure–dynamics correlation molecular dynamics simulation

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

Effect of icosahedral clusters on β-relaxations in metallic glasses

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Chinese Physics B 2017年第1期26卷 86-90页

作者： X Q Gao Y T Sun z Wang m z li H Y Bai Institute of Physics Chinese Academy of Sciences Beijing 100190 China Department of Physics Renmin University of China Beijing 100872 China

The most pronounced β-relaxation was found in the Y-based binary metallic glasses（mGs）. The correlation betweenβ-relaxation and local atomic structure was studied. The dynamic mechanical measurements were performed for three chosen binary systems： zr-, Ti-, and Y-based mGs. The experimental results show that, in each system,the larger negative enthalpy of mixing（？Hm） between the component elements makes β-relaxation become more pronounced. The less negative value of ？Hm facilitates the formation of icosahedral clusters, which have a pinning effect on the excitation of β-relaxations and correspondingly make the β-relaxation become less pronounced. These chemical effects on β-relaxations can only be compared in the same mG system, and it is not suitable for the comparison between different systems due to the different features of the major metallic elements.

关键词： metallic glass β-relaxation enthalpy of mixing icosahedral clusters

Five-fold local symmetry in metallic liquids and glasses

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Chinese Physics B 2017年第1期26卷 10-19页

作者： m z li H L Peng Y C Hu F X li H P zhang W H Wang Department of Physics Beijing Key Laboratory of Opto-electronic Functional Materials ＆ Micro-nano Devices Renmin University of China Beijing 100872 China Institute of Physics Chinese Academy of Sciences Beijing 100091 China

The structure of metallic glasses has been a long-standing mystery. Owing to the disordered nature of atomic structures in metallic glasses, it is a great challenge to find a simple structural description, such as periodicity for crystals, for establishing the structure–property relationship in amorphous materials. In this paper, we briefly review the recent developments of the five-fold local symmetry in metallic liquids and glasses and the understanding of the structure–property relationship based on this parameter. Experimental evidence demonstrates that five-fold local symmetry is found to be general in metallic liquids and glasses. Comprehensive molecular dynamics simulations show that the temperature evolution of five-fold local symmetry reflects the structural evolution in glass transition in cooling process, and the structure–property relationship such as relaxation dynamics, dynamic crossover phenomena, glass transition, and mechanical deformation in metallic liquids and glasses can be well understood base on the simple and general structure parameter of five-fold local symmetry.

关键词： metallic glass structure–property relation five-fold local symmetry

Two-stage double peaks ageing and its effect on stress corrosion cracking susceptibility of Al-zn-mg alloy

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Journal of materials Science & Technology 2018年第7期34卷 1250-1257页

作者： Y.L.Wang H.C.Jiang z.m.li D.S.Yan D.zhang L.J.Rong CAS Key Laboratory of Nuclear materials and Safety Assessment Institute of Metal Research Chinese Academy of Sciences School of materials Science and Engineering University of Science and Technology of China

Different artificial two-stage ageing behaviors and their effect on stress corrosion cracking （SCC） susceptibility of AI-zn-mg alloy have been investigated. The experimental results show that two hardness peaks present on the second-stage ageing-hardening curve when the first-stage ageing is dealt with comparatively lower temperature than the conventional one. The first peak is caused by dispersive and evenly distributed G.P. zones, while η ′phases and coarsened G.P. zones contribute to the second peak. Tensile strength of experimental alloy raises 9.6% （33.2 mPa） and SCC susceptibility decreases 38.9% by applying the second peak ageing regime instead of conventional T73. AI-zn-mg alloy obtains high strength and SCC resistance due to its finely dispersive matrix precipitates （mPts）, coarsened and discontinuous grain boundary precipitates （GBPs）, as well as the narrow precipitate free zone （PFz） in the second peak ageing condition. 2017 Published by Elsevier Ltd on behalf of The editorial office of Journal of materials Science ＆ Technology.

关键词： Al-zn-mg alloy Two-stage ageing Double peaks ageing Stress corrosion cracking (SCC) susceptibility Grain boundary precipitates (GBPs)

Targeting epigenetic mechanisms in amyloid-β-mediated Alzheimer’s pathophysiology:unveiling therapeutic potential

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Neural Regeneration Research 2025年第1期20卷 54-66页

作者： Jennie z.li Nagendran Ramalingam Shaomin li Ann Romney Center for Neurologic Diseases Brigham and Women’s Hospital and Harvard Medical SchoolBostonMAUSA

Alzheimer’s disease is a prominent chronic neurodegenerative condition characterized by a gradual decline in memory leading to *** evidence suggests that Alzheimer’s disease is associated with accumulating various amyloid-βoligomers in the brain,influenced by complex genetic and environmental *** memory and cognitive deficits observed during the prodromal and mild cognitive impairment phases of Alzheimer’s disease are believed to primarily result from synaptic *** life,environmental factors can lead to enduring changes in gene expression and the emergence of brain *** changes,known as epigenetic modifications,also play a crucial role in regulating the formation of synapses and their adaptability in response to neuronal *** this context,we highlight recent advances in understanding the roles played by key components of the epigenetic machinery,specifically DNA methylation,histone modification,and microRNAs,in the development of Alzheimer’s disease,synaptic function,and activity-dependent synaptic ***,we explore various strategies,including enriched environments,exposure to non-invasive brain stimulation,and the use of pharmacological agents,aimed at improving synaptic function and enhancing long-term potentiation,a process integral to epigenetic ***,we deliberate on the development of effective epigenetic agents and safe therapeutic approaches for managing Alzheimer’s *** suggest that addressing Alzheimer’s disease may require distinct tailored epigenetic drugs targeting different disease stages or pathways rather than relying on a single drug.

关键词： Alzheimer’s disease DNA methylation enriched environments histone modification microRNAs non-invasive brain stimulation synaptic plasticity

SPECIFIC ACTIVITY DETERmINATION OF ACETOLACTATE SYNTHASE FROm mAIzE (zEA mAYS L.)

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SPECIFIC ACTIVITY DETERMINATION OF ACETOLACTATE SYNTHASE FRO...

Universal basis underlying temperature, pressure and size induced dynamical evolution in metallic glass-forming liquids

The 18th Asian-Pacific Weed Science Society Conference

作者： z.J.Fan C.F.Qian z.m.li L.X.Wang Institute of Elemento-Organic Chemistry Nankai UniversityNational Key Laboratory of Elemento-Organic ChemistryTianjin 300071China Department of Applied Chemistry China Agricultural UniversityKey Laboratory of Pesticide Chemistry & Application Technology of Ministry of AgricultureBeijing 100094China

A normal spectrophotometric method has been established for determination specific activity of acetolactate synthase extracted from maize(zea mays L.).In this study,the condition of enzyme reaction and decarboxylation of acetolactate and condition of color development of reaction complex have been *** red color complex of acetion reacted wthα-naphthol and creatine was stable at room temperature within 90 *** method has been used as determination of activity for ALS in vitro and in vivo screening model of high efficacy *** had high in vitro ALS activity to maize CAU 108,which I was 3.33±0.82 nmol·L,while 2-chlorobenzenesulfonamide had almost no inhibition to ALS from maize CAU 108 in *** same results were observed in in vivo A1S study of chlorsulfuron and 2- chlorobenzenesulfonamide indicated.

关键词： Acetolactate synthase specific activity maize(zea mays L.) chlorsulfuron 2-chlorobenzenesulfonamide

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Chinese Physics B 2024年第1期33卷 134-142页

作者：张华平范蓓蓓吴佳琦李茂枝 Department of Physics Beijing Key Laboratory of Opto-electronic Functional Materials&Micro-nano DevicesRenmin University of ChinaBeijing 100872China Songshan Lake materials Laboratory Dongguan 523808China Key Laboratory of Quantum State Construction and manipulation Renmin University of ChinaBeijing 100872China

The dramatic temperature-dependence of liquids dynamics has attracted considerable scientific interests and efforts in the past decades, but the physics of which remains elusive. In addition to temperature, some other parameters, such as pressure, loading and size, can also tune the liquid dynamics and induce glass transition, which makes the situation more complicated. Here, we performed molecular dynamics simulations for Ni_(50)zr_(50) bulk liquid and nanodroplet to study the dynamics evolution in the complex multivariate phase space, especially along the isotherm with the change of pressure or droplet size. It is found that the short-time Debye–Waller factor universally determines the long-time relaxation dynamics no matter how the temperature, pressure or size changes. The basic correlation even holds at the local atomic scale. This finding provides general understanding of the microscopic mechanism of dynamic arrest and dynamic heterogeneity.

关键词： metallic glass-forming liquids structure relaxation dynamical heterogeneity Debye–Waller factor

Effect of Ti-Cr-V alloy as a dopant on the dehydriding kinetics of li-mg-N-H system

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Effect of Ti-Cr-V alloy as a dopant on the dehydriding kinet...