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Dislocation density-me diate d creep ageing behavior of an Al-Cu-Li alloy

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Journal of Materials Science & Technology 2024年第7期174卷 204-217页

作者： Chang Zhou Lihua zhan Chunhui liu Minghui Huang College of Mechanical and Electrical Engineering Central South UniversityChangsha 410083China State Key Laboratory of Precision Manufacturing for Extreme Service Performance Central South UniversityChangsha 410083China Light Alloys Research Institute Central South UniversityChangsha 410083China

Creep aging is well-known to be a time-dependent,coupled process of deformation and precipitation strengthening for age-hardening *** existing mechanisms are mainly attributed to those interac-tions between atomic diffusion and dislocation ***,an understanding of the relationship between dislocation density and a special multistage creep behavior,i.e.,double steady creep feature,is still far *** we investigate the effect of various dislocation density levels on such an abnormal multistage creep of an Al-Cu-Li *** find that the increased dislocation densities enable an apparent time decrease(from 6.2 h to 0.8 h)of their first steadyⅡ-*** yield strength of post-aged sam-ples increases from 425.0 MPa to 580.0 MPa while the corresponding elongation decreases from 12.3%to 7.3%for the creep-aged samples#1 to#*** results also reveal that a great difference in dislocation configuration,tailored by various density levels,results in varying creep processes of theⅡ-*** stage is closely related to the nucleation and early growth of T_(1)*** number densities(maximum:2.9×10^(19)m^(-3))and the average length(maximum:21.3 nm)of T_(1)precipitates are much smaller than those of the stable peak-aged T_(1)phases,suggesting that creepⅡ-stage of all three creep-aged samples is dominant by the nucleation and initial growth of those T_(1)*** study provides valuable insights into the dislocation density-mediated creep deformation of an Al-Cu-Li alloy.

关键词： Dislocation density Al-Cu-Li alloy Creep ageing T_(1)precipitation

Experimental investigation of engineered geopolymer composite for structural strengthening against blast loads

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Defence Technology（防务技术） 2024年第2期32卷 496-509页

作者： Shan liu Chunyuan liu Yifei Hao Yi zhang Li Chen zhan Li Key Laboratory of Coast Civil Structure Safety of Ministry of Education Tianjin UniversityTianjin 300072China Tianjin Key Laboratory of Prefabricated Buildings and Intelligent Construction Hebei University of TechnologyTianjin 300400China Institute of Defense Engineering AMSPLABeijing 100850China Engineering Research Center of Safety and Protection of Explosion&Impact of Ministry of Education Southeast UniversityNanjing 211189JiangsuChina State Key Laboratory of Disaster Prevention&Mitigation of Explosion&Impact Army Engineering University of the PLANanjing 210007JiangsuChina

The recent increase in blast/bombing incidents all over the world has pushed the development of effective strengthening approaches to enhance the blast resistance of existing civil *** geopolymer composite(EGC)is a promising material featured by eco-friendly,fast-setting and strain-hardening characteristics for emergent strengthening and ***,the fiber optimization for preparing EGC and its protective effect on structural elements under blast scenarios are *** this study,laboratory tests were firstly conducted to evaluate the effects of fiber types on the properties of EGC in terms of workability,dry shrinkage,and mechanical properties in compression,tension and *** experimental results showed that EGC containing PE fiber exhibited suitable workability,acceptable dry shrinkage and superior mechanical properties compared with other types of *** that,a series of field tests were carried out to evaluate the effectiveness of EGC retrofitting layer on the enhancement of blast performance of typical *** tests include autoclaved aerated concrete(AAC)masonry walls subjected to vented gas explosion,reinforced AAC panels subjected to TNT explosion and plain concrete slabs subjected to contact *** was found that EGC could effectively enhance the blast resistance of structural elements in different *** AAC masonry walls and panels,with the existence of EGC,the integrity of specimens could be maintained,and their deflections and damage were significantly *** plain concrete slabs,the EGC overlay could reduce the diameter and depth of the crater and spallation of specimens.

关键词： Engineered geopolymer composites Fiber optimization Strengthening material Blast resistance Masonry wall Reinforced AAC panel Plain concrete slab

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Experimental Investigation on Vertical Hydraulic Transport of Ores in Deepsea Mining

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China Ocean Engineering 2024年第1期38卷 42-53页

作者： liu Lei liu Jian-cheng LI Xin XU Li-xin zhanG Xiu-zhan State Key Laboratory of Ocean Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Naval Architecture Ocean and Civil EngineeringShanghai Jiao Tong UniversityShanghai 200240China Sanya Yazhou Bay Institution of Deep-sea Sci-Tech Shanghai Jiao Tong UniversitySanya 572000China China Merchants Marine And Offshore Research Institute Co. Ltd.Shenzhen 518067China China Merchants Deepsea Research Institute(Sanya)Co. Ltd.Sanya 572000China School of Naval Architecture and Ocean Engineering Jiangsu University of Science and TechnologyZhenjiang 212100China

Deepsea mining has been proposed since the 1960s to alleviate the lack of resources on *** hydraulic transport of collected ores from the seabed to the sea surface is considered the most promising method for industrial *** the present study,an indoor model test of the vertical hydraulic transport of particles was conducted.A noncontact optical method has been proposed to measure the local characteristics of the particles inside a vertical pipe,including the local concentration and particle *** hydraulic gradient of ore transport was evaluated with various particle size distributions,particle densities,feeding concentrations and mixture flow *** transport,the local concentration is larger than the feeding concentration,whereas the particle velocity is less than the mixture *** qualitative effects of the local concentration and local fluid velocity on the particle velocity and slip velocity were *** local fluid velocity contributes significantly to particle velocity and slip velocity,whereas the effect of the local concentration is marginal.A higher feeding concentration and mixture flow velocity result in an increased hydraulic *** effect of the particle size gradation is slight,whereas the particle density plays a crucial role in the transport.

关键词： deepsea mining vertical hydraulic transport experiment flow characteristics

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Iron-nickel alloy particles with N-doped carbon “armor” as a highly selective and long-lasting catalyst for the synthesis of Nbenzylaniline molecules

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Nano Research 2024年第4期17卷 2308-2319页

作者： Gang Wang Longchao Sun Wanyi liu Haijuan zhan Shuxian Bi College of Chemistry and Chemical Engineering Ningxia UniversityYinchuan 750021China

A scalable strategy for the convenient and rapid preparation of nitrogen-doped carbon-coated iron-based alloy catalysts was *** controlling the type and amount of metal salts in the precursor,various types of nitrogen-doped carbon-coated alloy catalysts can be prepared in a targeted ***_(2)Ni2@CN materials with small particle sizes and relatively homogeneous basic sites showed promising results in the N-alkylation reaction of benzyl alcohol with aniline(optimum yield:99%).It is worth noting that the catalyst can also be magnetically separated and recovered after the reaction,and its performance can be regenerated through simple ***,it was confirmed by kinetic experiments that the activation of C–H at the benzyl alcohol benzylic position is the rate-determining step(RDS).According to density flooding theory calculations,Fe_(2)Ni2@CN catalysts require less energy than other materials(Fe@CN and Ni@CN)for the RDS(dehydrogenation reaction)*** N-alkylation reactions are more easily carried out on Fe_(2)Ni2@CN catalysts,which may be the reason for the best catalytic activity of Fe-Ni alloy *** carbon-coated alloy materials will show great potential in more types of heterogeneous catalysis.

关键词： iron-nickel alloy catalyst N-alkylation reaction magnetic separation reaction path dehydrogenation reaction

Impact and prediction of pollutant on mangrove and carbon stocks:A machine learning study based on urban remote sensing data

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Geoscience Frontiers 2024年第3期15卷 401-418页

作者： Mengjie Xu Chuanwang Sun Yanhong zhan Ye liu Institute of Artificial Intelligence Xiamen UniversityXiamen 361005FujianChina China Center for Energy Economics Research School of EconomicsXiamen UniversityXiamen 361005FujianChina Laboratory of Smart Energy and Green Economy Institute of Artificial IntelligenceXiamen UniversityXiamen 361005FujianChina Department of Public Finance School of EconomicsXiamen UniversityXiamen 361005China

Mangrove ecosystems have important ecological and economic values,especially their ability to store ***,in recent years,human disturbance has accelerated mangrove *** them,the emission of pollutants cannot be *** is of great significance for carbon emission reduction and ecological protection to study the impacts of different pollutants on mangroves and their carbon *** on the remote sensing data of coastal areas south of the Yangtze River in China's Mainland,this paper builds the ensemble learning model Random Forest(RF)and Gradient Boosting Regression(GBR)to empirically analyse the relationship between industrial wastewater,industrial sulfur dioxide(SO2),PM2.5 and mangrove *** results show that the pollutant concentration of meteorological normalisation is more *** importance of pollutants presents regional *** area of mangroves in different cities and the corresponding total carbon stocks show different trends with the increase or decrease of pollutants,and there is a dynamic balance between urban pollutant discharge and mangrove growth in some *** research in this paper provides an analysis and explanation from the perspective of machine learning to explore the relationship between mangroves and pollutants and at the same time,provides scientific suggestions for the formulation of future pollutant emission policies in different cities.

关键词： Mangrove forests Pollutants Machine learning model Carbon stocks Regional heterogeneity

Bridging microstructure and crystallography with the crack propagation behavior in Ti-6Al-4V alloy fabricated via dual laser beam bilateral synchronous welding

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Journal of Materials Science & Technology 2024年第7期174卷 1-14页

作者： Tingyan Yan Yuan liu Jianfeng Wang Yong Zheng Xiaohong zhan College of Materials Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China

The microstructure evolution and crack propagation behavior were systematically and thoroughly inves-tigated inα/βTi-6Al-4V alloy obtained under the inhomogeneous heating effect of a coupled dual laser beam via a combination of postmortem electron backscattering diffraction analyses and numerical *** effect of microstructural attributes(grain size,grain boundary,dislocation)on the fracture property and crack propagation behavior was investigated based on thermodynamic and crystallographic analyses,as well as the examinations of dislocation density and the Burgers *** quantifying the degree of variant selection using the degree of variant selection(DVS)equation,it was found that the higher the energy input,the weaker the variant selection,as the secondaryαphase suppresses further dislocation-induced variant selection via autocatalytic nucleation and *** proportion of high an-gle grain boundaries(HAGBs)concentrated around 60°gradually increases with improving cooling rate,mainly due to the change in the tendency of martensite transformation to be *** grain refine-ment was the primary mechanism for the enhancement of Ti-6Al-4V alloy T-joints,while the suppression of crack propagation by HAGBs also played a crucial role in improving strength and *** crack propagation direction frequently changes when the order is approximately parallel to the short axis ofαmartensite grains,forming a zigzag propagation *** above findings should shed light on optimiz-ing dual laser beam bilateral synchronous welding(DLBSW)technology to tailor the microstructure and improve the mechanical properties of Ti-6Al-4V alloy T-joints.

关键词： Ti-6Al-4V alloy Microstructure Grain refinement Crack propagation Dual laser beam bilateral synchronous welding

Singlet oxygen-dominated peroxymonosulfate activation by layered crednerite for organic pollutants degradation in high salinity wastewater

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Journal of Environmental Sciences 2024年第1期135卷 86-96页

作者： Chengji Sui Zixuan Nie Huan liu Grzegorz Boczkaj Weizhen liu Lingshuai Kong Jinhua zhan Key Laboratory for Colloid&Interface Chemistry of Education Ministry Department of ChemistryShandong UniversityJinan 250100China School of Environment and Energy Guangdong Provincial Key Laboratory of Solid Wastes Pollution Control and RecyclingSouth China University of TechnologyGuangzhou 510006China Gdansk University of Technology Faculty of Civil and Environmental EngineeringDepartment of Sanitary EngineeringG.Narutowicza St.11/1280-233 GdanskPoland EkoTech Center Gdansk University of TechnologyG.Narutowicza St.11/1280-233 GdanskPoland

Advanced oxidation processes have been widely studied for organic pollutants treatment in water,but the degradation performance of radical-dominated pathway was severely inhibited by the side reactions between the anions and radicals,especially in high salinity ***,a singlet oxygen(^(1)O_(2))-dominated non-radical process was developed for organic pollutants degradation in high salinity wastewater,with layered crednerite(CuMnO_(2))as catalysts and peroxymonosulfate(PMS)as *** on the experiments and density functional theory calculations,^(1)O_(2)was the dominating reactive species and the constructed Cu-O-Mn with electron-deficient Mn captured electron from PMS promoting the generation of^(1)O_(2).The rapid degradation of bisphenol A(BPA)was achieved by CuMnO_(2)/PMS system,which was 5-fold and 21-fold higher than that in Mn_(2)O_(3)/PMS system and Cu_(2)O/PMS *** CuMnO_(2)/PMS system shown prominent BPA removal performance under high salinity conditions,prominent PMS utilization efficiency,outstanding total organic carbon removal rate,wide range of applicable pH and good *** work unveiled that the^(1)O_(2)-dominated non-radical process of CuMnO_(2)/PMS system overcame the inhibitory effect of anions in high salinity conditions,which provided a promising technique to remove organic pollutants from high saline wastewater.

关键词： Singlet oxygen Non-radical process High salinity Mixed metal oxides Wastewater treatment

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Anomalous response to creep deformation from dislocation density during electrically assisted creep aging

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Rare Metals 2024年第10期43卷 5268-5283页

作者： Chang Zhou Li-Hua zhan Chun-Hui liu Ming-Hui Huang College of Mechanical and Electrical Engineering Central South University Light Alloys Research Institute State Key Laboratory of Precision Manufacturing for Extreme Service PerformanceCentral South University

Adding numerous dislocations into metallic materials before the forming stage significantly enhances their deformability. However, this beneficial effect of dislocation defects may not have a simple monotonic relationship with increased dislocation density during electroplastic deformation. This is due to the complex interactions among the drifting electrons, dislocations and solute atoms. This study explores the effect of diverse initial dislocation densities on creep deformation during electrically aided creep aging of an aluminum–lithium alloy. Surprisingly, we discovered a threshold value for the dislocation density that affects electroplastic creep, i.e., an enhanced effect from dislocations weakens when exceeding this density threshold(an anomalous response to creep). Microstructural data also reveal that such an anomalous response originates mainly from differences in various dislocation density-tailored configurations, which can influence the dislocation motions and precipitation kinetics of the strengthening T1precipitates under the same action of pulsed currents. This study provides important insights into the dislocation density-mediated electroplastic creep of an aluminum–lithium alloy.

关键词： Al–Cu–Li alloy Creep aging Dislocation density Pulsed currents

Achieving single-cell-resolution lineage tracing in zebrafish by continuous barcoding mutations during embryogenesis

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Journal of Genetics and Genomics 2024年第9期51卷 947-956页

作者： zhan.liu Hui Zeng Huimin Xiang Shanjun Deng Xionglei He State Key Laboratory of Biocontrol School of Life SciencesSun Yat-Sen UniversityGuangzhouGuangdong 510275China

Unraveling the lineage relationships of all descendants from a zygote is fundamental to advancing our understanding of developmental and stem cell ***,existing cell barcoding technologies in zebrafish lack the resolution to capture the majority of cell divisions during embryogenesis.A recently developed method,a substitution mutation-aided lineage-tracing system(SMALT),successfully reconstructed high-resolution cell phylogenetic trees for Drosophila ***,we implement the SMALT system in zebrafish,recording a median of 14 substitution mutations on a one-kilobase-pair barcoding sequence for one-day post-fertilization *** this system,we reconstruct four cell lineage trees for zebrafish fin cells,encompassing both original and regenerated *** tree consists of hundreds of internal nodes with a median bootstrap support of 99%.Analysis of the obtained cell lineage trees reveals that regenerated fin cells mainly originate from cells in the same part of the *** multiple times sampling germ cells from the same individual,we show the stability of the germ cell pool and the early separation of germ cell and somatic cell *** system offers the potential for reconstructing high-quality cell phylogenies across diverse tissues,providing valuable insights into development and disease in zebrafish.

关键词： Lineage tracing Cellular barcoding Zebrafishcell phylogeny Fin regeneration Germcell lineage