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Science China(Technological Sciences) 2023年第8期66卷 2432-2440页

作者： LIU JingYun LU HaiBao FU Yong-Qing Science and Technology on Advanced Composites in Special Environments Laboratory Harbin Institute of TechnologyHarbin 150080China Faculty of Engineering and Environment Northumbria UniversityNewcastle upon TyneNE18STUK

Glass transition plays a critical role to determine the dynamic behaviors of amorphous shape memory polymers(SMPs).However,the fundamental relationships between shape memory effect(SME)and dynamic glass transition have not been well understood,even though this topic has been studied for decades.In this study,we apply a mean-square displacement function of Adam-Gibbs(AG)domain size model to explore metastable glass transition between normal glass state and rubbery state of amorphous SMPs,based on both mode-coupling theory and mean-field model.A statistic viscosity equation is formulated to study the dynamic glass transition of metastable AG domains in an amorphous SMP.A dynamically spinodal model is also developed to connect dynamic glass transitions to thermomechanical processes,based on statistic viscosity equation and phase transition model.Furthermore,using the spinodal models,multiple shape memory behaviors have been predicted for amorphous SMPs with dual-,triple-and quadruple-SMEs,resulted from their different routes of themomechanical evolutions.Finally,the proposed models are verified using the experimental data reported in literature.

关键词： shape memory polymer glass transition dynamics metastable

metastable Iron Sulfides: A Versatile Antibacterial Candidate with Multiple Mechanisms against Bacterial Resistance

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Accounts of Materials Research 2023年第2期4卷 115-132页

作者： Haolin Cao Qian Wang Xiaonan Wang Lei Chen Jing Jiang Lizeng Gao CAS Engineering Laboratory for Nanozyme Laboratory of Protein and Peptide DrugsInstitute of BiophysicsChinese Academy of SciencesBeijing 100101China Graduate School of University of Chinese Academy of Sciences Beijing 101408China Nanozyme Medical Center School of Basic Medical SciencesZhengzhou UniversityZhengzhou 450001China

Bacterial infections pose an ongoing threat to global human health,an issue of growing urgency due to the emergence of resistance against many currently available antibiotics.Recently,the World Health Organization(WHO)launched a global appeal for the development of novel antibiotics to combat this issue.Ideal antibiotics should possess specific antibacterial effects,without causing resistance.However,the discovery of different antibiotics is lagging the development of drug-resistant bacteria.Many newly developed antibiotics not only are rapidly resisted by bacteria but also are ineffective against persistent bacteria embedded in biofilms and host cells.To tackle these challenges,innovative concepts and approaches are required for the discovery of novel antibacterial candidates.Agents for use against pathogenic bacteria were developed long before the discovery of antibiotics.For 3000 years,garlic has been considered an efficient antibacterial compound,utilized to prevent and treat bacterial infection worldwide,although the specific mechanisms remain unclear.Modern research shows that sulfur-containing chemicals are the primary active constituents of garlic and play key roles in its inherent antimicrobial activity,such as diallyl disulfide(DADS)and diallyl trisulfide(DATS).In contrast,inorganic sulfides for antibacterial use have not been deeply studied.It has been well-known that iron sulfides are an essential part of the geochemical and biological sulfur cycles.Both stable and metastable iron sulfides can be formed under abiotic sediment conditions and biotic process.In particular,certain bacteria species growth need iron sulfide as nutrient source or produce iron sulfide.In addition,iron sulfur clusters as special metastable iron sulfide take part in many important metabolic pathways in most organisms.These physicochemical and biological properties inspire us that iron sulfides are a type of valuable material for investigation and utilization.Below we will introduce a new antibacterial candidate based on iron su

关键词： process sulfide metastable

Laser-Derived Interfacial Confinement Enables Planar Growth of 2D SnS_(2) on Graphene for High-Flux Electron/Ion Bridging in Sodium Storage

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Nano-Micro Letters 2022年第6期14卷 65-80页

作者： Xiaosa Xu Fei Xu Xiuhai Zhang Changzhen Qu Jinbo Zhang Yuqian Qiu Rong Zhuang Hongqiang Wang State Key Laboratory of Solidification Processing Centre for Nano Energy MaterialsSchool of Materials Science and EngineeringNorthwestern Polytechnical UniversityShaanxi Joint Laboratory of Graphene(NPU)Xi’an 710072People’s Republic of China

Establishing covalent heterointerfaces with face-to-face contact is promising for advanced energy storage,while challenge remains on how to inhibit the anisotropic growth of nucleated crystals on the matrix.Herein,faceto-face covalent bridging in-between the 2 D-nanosheets/graphene heterostructure is constructed by intentionally prebonding of laser-manufactured amorphous and metastable nanoparticles on graphene,where the amorphous nanoparticles were designed via the competitive oxidation of Sn-O and Sn-S bonds,and metastable feature was employed to facilitate the formation of the C-S-Sn covalent bonding in-between the heterostructure.The face-to-face bridging of ultrathin SnS;nanosheets on graphene enables the heterostructure huge covalent coupling area and high loading and thus renders unimpeded electron/ion transfer pathways and indestructible electrode structure,and impressive reversible capacity and rate capability for sodium-ion batteries,which rank among the top in records of the SnS_(2)-based anodes.Present work thus provides an alternative of constructing heterostructures with planar interfaces for electrochemical energy storage and even beyond.

关键词： Laser-manufacturing metastable Interfacial engineering Covalent bridging Na-storage

metastable　PHASE　AND　AGE　HARDENING　IN　RAPIDLY－SOLIDIFIED　SILVER－RICH　Ag－Gd　ALLOYS

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中国有色金属学会会刊：英文版 1996年第4期6卷 138-143页

作者： Ning Yuantao(Institute of Precious Metals,Kunming 650221) Institute of Precious Metals Kunming 650221 China

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关键词： metastable phase age hardening rapidly-solidified Ag-Gd alloy

Development of carrier-free nanocrystals of poorly water-soluble drugs by exploring metastable zone of nucleation

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Acta Pharmaceutica Sinica B 2019年第1期9卷 118-127页

作者： Xiaoting Ren Jianping Qi Wei Wu Zongning Yin Tonglri Li Yi Lu Key Laboratory of Drug Targeting and Drug Delivery Systems West China School of Pharmacy Sichuan University Department of Pharmaceutics School of Pharmacy Fudan University Department of Industrial and Physical Pharmacy College of Pharmacy Purdue University

There has been increasing interest in research and development of nanocrystals for the delivery of poorly water-soluble drugs that can be directly produced from solution. Compared with traditional carrier-based or encapsulation designs, drug nanocrystals circumvent possible side-effects due to carrier polymers and poor stability issues associated with encapsulation. The production of carrier-free nanocrystals requires careful control of nucleation and thus a thorough understanding of the relevant solution's metastable zone. A solution may stay supersaturated without forming any nuclei and become metastable. The maximal degree of supersaturation is known as the metastable zone width. When nucleation is triggered directly from the metastable zone, it helps to produce homogeneous nuclei leading to uniform nanocrystals. Herein, we report a study in which the solubility and metastable limit of paclitaxel(PTX) in ethanol aqueous solution were measured at 40 °C. A wide range of metastable compositions were studied to prepare carrier-free PTX nanocrystals with particle size smaller than250 nm and PDI less than 0.25. Compared with the raw material, dissolution rate of PTX nanocrystals was significantly increased. The study enables production of high-quality drug nanocrystals for treating patients.

关键词： Nanocrystals metastable zone Nucleation Sonication Dissolution Paclitaxel

Investigation of the stable and the metastable liquidus miscibility gaps in Fe–Sn and Fe–Cu binary systems

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International Journal of Minerals,Metallurgy and Materials 2019年第11期26卷 1427-1435页

作者： Jiang-tao Gao Chang-rong Li Cui-ping Guo Zhen-min Du School of Materials Science and Engineering University of Science and Technology Beijing

Two kinds of experimental methods were tried in the present work:(i)the powder metallurgy method combined with differential thermal analysis(DTA)to determine the metastable liquidus miscibility gap for a Fe–Cu binary system and(ii)the high-temperature melting method combined with isothermal treatment to determine the stable liquidus miscibility gap for a Fe–Sn binary system.The experimental method was adopted according to the characteristics of the liquidus miscibility gap of the specific system.Using the powder metallurgy method,a uniform microstructure morphology and chemical composition was obtained in the DTA specimen,and the phase-separation temperature of the supercooled metastable liquid was measured.The isothermal treatment was applied for the samples inside the stable liquidus miscibility gap;here,equilibrated compositions were reached,and a layered morphology was formed after rapid cooling.The liquid miscibility gaps of the Fe–Cu and Fe–Sn binary systems were measured,and the peak temperatures of the corresponding miscibility gaps were determined to be about 1417°C at x(Cu)=0.465 at%and 1350°C at x(Sn)=0.487 at%,respectively.On the basis of the experimental results,both the Fe–Cu and the Fe–Sn binary systems were thermodynamically assessed.

关键词： binary systems miscibility gap differential thermal analysis(DTA) metastable state

Comparative Study on Solid-State and metastable Liquid-State Aging for SAC305/Cu Joints

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Acta Metallurgica Sinica(English Letters) 2019年第5期32卷 629-637页

作者： Shuang Li Xiao-Wu Hu Wei-Guo Zhang Yu-Long Li Xiong-Xin Jiang Key Lab for Robot and Welding Automation of Jiangxi Province Mechanical and Electrical Engineering SchoolNanchang University College of Mechanical and Electronic Engineering Northwest A&F University

In order to study the in?uence of the physical state of solder on the interfacial reaction of dip-soldered Sn-3.0 Ag-0.5 Cu/Cu system, two kinds of experiments were designed, including:(1) solid-state aging between the solder and Cu substrate;(2)liquid-state aging between the metastable supercooled liquid-state solder and Cu substrate. The aging times were 30, 60,120 and 180 min, respectively, and the aging temperature was 8 ℃ lower than the melting point of the Sn-3.0 Ag-0.5 Cu(SAC305) alloy(217 ℃). The experimental data revealed that the physical state of the solder obviously affected the formation of the intermetallic compound(IMC), and resulted in the difference in the diffusion of atoms on the interface between the SAC305 solder and Cu substrate. The IMC interface after aging for 30 min presents unique characteristics compared with that of the sample after dip soldering. The IMC interface of solid-state aged SAC305/Cu couple is relatively planar, while the IMC interface under metastable supercooled liquid-state aging conditions presents scallop-like shape.

关键词： Lead-free solder Supercooling metastable liquid state Aging Intermetallic compound

Single‐precursor phase‐controlled synthesis of copper selenide nanocrystals and their conversion to amorphous hollow nanostructures

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SmartMat 2023年第3期4卷 120-132页

作者： Feifan Chen Yadong Zhang Lijun Hu Lifang Zheng Feiyue Ge Changsheng Feng Dan Xu Chen‐Lei Tao Xue‐Jun Wu State Key Laboratory of Coordination Chemistry School of Chemistry and Chemical EngineeringNanjing UniversityNanjingChina

The crystal phases are essential to the physicochemical properties and functionalities of materials.Copper selenide has emerged as an important and appealing semiconductor,which can exist in a variety of polymorphic phases.However,the richness of polymorphs also makes it a challenge to the direct preparation of copper selenide nanocrystals with tunable phases.Herein,two polymorphs,that is,quasitetragonal Cu2−xSe nanocubes and metastable wurtzite Cu2Se nanodisks,are successfully synthesized by using a single precursor,copper(I)selenocyanate(CuSeCN),as the Cu and Se sources.The key to phase modulation is the optimal choice of the ligand in the synthesis.The as‐prepared nanocrystals possess different morphologies and compositions,giving rise to distinct optical properties and electrical conductivities.Interestingly,the copper selenide nanocrystals can provide a platform for the rational construction of two types of amorphous hollow Au─Cu─Se nanostructures by reaction with Au(I)precursor,in which their final shapes are well kept as that of the original nanocrystal templates.This work provides an easy strategy for the phase‐controlled synthesis of copper selenide nanocrystals and enables the design of new materials for broad applications.

关键词： amorphous copper selenides hollow nanostructures metastable polymorphs

Thermodynamical and topological properties of metastable Fe_(3)Sn

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npj Computational Materials 2022年第1期8卷 2373-2384页

作者： Chen Shen Ilias Samathrakis Kun Hu Harish K.Singh Nuno Fortunato Huashan Liu Oliver Gutfleisch Hongbin Zhang School of Materials Science Technical University DarmstadtOtto-Berndt-Straße 3Darmstadt64287Germany School of Materials Science and Engineering Central South UniversityLushan South Road 932410083ChangshaChina

The Fe–Sn-based kagome compounds attract intensive attention due to its attractive topological transport and rich magnetic properties.Combining experimental data,first-principles calculations,and Calphad assessment,thermodynamic and topological transport properties of the Fe–Sn system were investigated.Density functional theory(DFT)calculations were performed to evaluate the intermetallics’finite-temperature heat capacity(C_(p)).A consistent thermodynamic assessment of the Fe–Sn phase diagram was achieved by using the experimental and DFT results,together with all available data from previous publications.Here,we report that the metastable phase Fe_(3)Sn was introduced into the current metastable phase diagram,and corrected phase locations of Fe_(5)Sn_(3)and Fe_(3)Sn_(2)under the newly measured corrected temperature ranges.Furthermore,the anomalous Hall conductivity and anomalous Nernst conductivity of Fe_(3)Sn were calculated,with magnetization directions and doping considered as perturbations to tune such transport properties.It was observed that the enhanced anomalous Hall and Nernst conductivities originate from the combination of nodal lines and small gap areas that can be tuned by doping Mn at Fe sites and varying magnetization direction.

关键词： intermetallics metastable magnetization

Topological graph-based analysis of solid-state ion migration

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npj Computational Materials 2023年第1期9卷 1337-1341页

作者： Jimmy-Xuan Shen Haoming Howard Li Ann Rutt Matthew K.Horton Kristin A.Persson Materials Science Division Lawrence Livermore National LaboratoryLivermoreCAUSA Materials Sciences Division Lawrence Berkeley National LaboratoryBerkeleyUSA Department of Material Science and Engineering University of CaliforniaBerkeleyCAUSA Molecular Foundry Lawrence Berkeley National LaboratoryBerkeleyUSA

To accelerate the development of ion conducting materials,we present a general graph-theoretic analysis framework for ion migration in any crystalline structure.The nodes of the graph represent metastable sites of the migrating ion and the edges represent discrete migration events between adjacent sites.Starting from a collection of possible metastable migration sites,the framework assigns a weight to the edges by calculating the individual migration energy barriers between those sites.Connected pathways in the periodic simulation cell corresponding to macroscopic ion migration are identified by searching for the lowest-cost cycle in the periodic migration graph.To exemplify the utility of the framework,we present the automatic analyses of Li migration in different polymorphs of VO(PO_(4)),with the resulting identification of two distinct crystal structures with simple migration pathways demonstrating overall<300 meV migration barriers.

关键词： analysis migration metastable