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Multi-layer multi-pass friction rolling additive manufacturing of Al alloy:Toward complex large-scale high-performance components

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International Journal of Minerals,Metallurgy and Materials 2025年第2期32卷 425-438页

作者： Haibin liu Run Hou Chenghao Wu Ruishan xie shujun Chen College of Mechanical&Energy Engineering Beijing University of TechnologyBeijing 100124China Chongqing Research Institute of Beijing University of Technology Chongqing 401121China

At present,the emerging solid-phase friction-based additive manufacturing technology,including friction rolling additive man-ufacturing(FRAM),can only manufacture simple single-pass *** this study,multi-layer multi-pass FRAM-deposited alumin-um alloy samples were successfully prepared using a non-shoulder tool *** material flow behavior and microstructure of the over-lapped zone between adjacent layers and passes during multi-layer multi-pass FRAM deposition were studied using the hybrid 6061 and 5052 aluminum *** results showed that a mechanical interlocking structure was formed between the adjacent layers and the adja-cent passes in the overlapped center *** friction and rolling of the tool head led to different degrees of lateral flow and plastic deformation of the materials in the overlapped zone,which made the recrystallization degree in the left and right edge zones of the over-lapped zone the highest,followed by the overlapped center zone and the non-overlapped *** tensile strength of the overlapped zone exceeded 90%of that of the single-pass deposition *** is proved that although there are uneven grooves on the surface of the over-lapping area during multi-layer and multi-pass deposition,they can be filled by the flow of materials during the deposition of the next lay-er,thus ensuring the dense microstructure and excellent mechanical properties of the overlapping *** multi-layer multi-pass FRAM deposition overcomes the limitation of deposition width and lays the foundation for the future deposition of large-scale high-performance components.

关键词： aluminum alloy additive manufacturing solid-state friction stir welding multi-layer multi-pass

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Dynamic Impact of High-Density Aluminum Foam

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Acta Mechanica solida sinica 2022年第2期35卷 198-214页

作者： Q.Peng J.xie H.s.Ma x.Ling x.liu Y.G.Wei LNM Institute of MechanicsChinese Academy of SciencesBeijing 100190China school of Engineering science University of Chinese Academy of SciencesBeijing 100049China school of Engineering and Technology China University of GeosciencesBeijing 100083China College of Engineering Peking UniversityBeijing 100871China

High-density aluminum foam can provide higher stiffness and absorb more energy during the impact Obtaining the constitutive law of such foam requires tri-axial tests with very high pressure,where difficulty may arise because the hydrostatic pressure can reach more than 30 *** this paper,instead of using tri-axial tests,we proposed three easier tests-tension,compression and shear to obtain the parameters of constitutive model(the Deshpande-Fleck model).To verify the constitutive model both statically and dynamically,we carried out addi-tional triaxial tests and direct impact tests,*** on the derived model,we performed finite element simulation to study the impact response of the present *** dimensional analysis,we proposed an empirical equation for a non-dimensional impact time the impact time divided by the time required for plastic wave travelling from the impact surface to the bottom surface,to det ermine the deformation charac teristic of the aluminum foam after *** the case with t_(d)≤1,the deformation tends to exhibit a shock-type characteristic,while for the case with t_(d)>5,the deformation tends to exhibit an upsetting-type characteristic.

关键词： High density aluminum Foam Deshpande-Fleck model Finite element method Impact analysis Plastic wave

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statistical analysis on the validity of the cold plasma approximation for chorus waves based on Van Allen Probe observations and their effects on radiation belt electrons

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Earth and Planetary Physics 2025年第1期9卷 159-170页

作者： AoJun Ren Jiang Yu Jing Wang ZuZheng Chen xiaoMan liu Planetary Environmental and Astrobiological Research Laboratory(PEARL) School of Atmospheric SciencesSun Yat-sen UniversityZhuhai Guangdong 519000China

Theoretical analysis has demonstrated that the dispersion relation of chorus waves plays an essential role in the resonant interaction and energy transformation between the waves and magnetospheric *** quantitative analyses often simplified the chorus dispersion relation by using the cold plasma ***,the applicability of the cold plasma assumption is doubtful,especially during geomagnetic *** here present a systematic statistical analysis on the validity of the cold plasma dispersion relation of chorus waves based on observations from the Van Allen Probes over the period from 2012 to *** statistical results show that the observed magnetic field intensities deviate substantially from those calculated from the cold plasma dispersion relation and that they become more pronounced with an increase in geomagnetic activity or a decrease in background plasma *** region with large deviations is mainly concentrated in the nightside and expands in both the radial and azimuthal directions as the geomagnetic activity increases or the background plasma density *** addition,the bounce-averaged electron scattering rates are computed by using the observed and cold plasma dispersion relation of chorus *** with usage of the cold plasma dispersion relation,usage of the observed dispersion relation considerably lowers the minimum resonant energy of electrons and lowers the scattering rates of electrons above tens of kiloelectronvolts but enhances those ***,these differences are more pronounced with the enhancement of geomagnetic activity or the decrease in background plasma density.

关键词： chorus waves cold plasma approximation dispersion relations scattering rates

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Anomalous quality factor evolution of induced transparency in a virtualized coupled-oscillator system

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science China(Physics,Mechanics & Astronomy) 2025年第1期Mechanics & Astronomy) .卷 148-155页

作者： Yunhan Yang Han Jia Tuo liu Yuzhen Yang Jun Yang Key Laboratory of Noise and Vibration Research Institute of Acoustics Chinese Academy of Sciences University of Chinese Academy of sciences state Key Laboratory of Acoustics Institute of Acoustics Chinese Academy of Sciences

The phenomenon of induced transparency, characterized by a high quality(Q) factor, holds significant importance in the fields of high-precision sensing, energy storage and wave manipulation. Conventional transparency systems are often constrained by the limited experimentally accessible parameter space and the lack of independent control over intrinsic parameters, thereby hindering advanced research on high-Q effects. Here we propose a virtualized coupled-oscillator system that enables reconfigurable induced transparency in the reflection spectrum. By virtually incorporating a pair of coupled oscillators into an individual acoustic meta-atom, we achieve the manipulation of induced transparency in a decoupled, wide-ranging, and elaborate manner. Exploiting the diverse evolutions across the intrinsic parameter space, we show experimentally a counter-intuitive increase in the Q-factor of the transparency window, which is attributed to the enhanced dissipation of the bright ***, a constant group delay at the center frequency is observed accompanying this evolution. Our work demonstrates an intriguing platform as well as a novel strategy to engineer high-Q induced transparency phenomenon, and paves the way towards applications in programmable acoustic sensors, filters and slow-wave devices.

关键词： induced transparency acoustic meta-atom high quality-factor scattering programmable intrinsic parameter

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Unraveling brain aging through the lens of oral microbiota

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Neural Regeneration Research 2025年第7期20卷 1930-1943页

作者： Qinchao Hu si Wang Weiqi Zhang Jing Qu Guang-Hui liu state Key Laboratory of Membrane Biology Institute of ZoologyChinese Academy of SciencesBeijingChina Hospital of stomatology Guanghua School of StomatologyGuangdong Provincial Key Laboratory of StomatologySun Yat-sen UniversityGuangzhouGuangdong ProvinceChina Advanced Innovation Center for Human Brain Protection and National Clinical Research Center for Geriatric Disorders Xuanwu HospitalCapital Medical UniversityBeijingChina Aging Translational Medicine Center International Center for Aging and CancerBeijing Municipal Geriatric Medical Research CenterXuanwu HospitalCapital Medical UniversityBeijingChina CAs Key Laboratory of Genomic and Precision Medicine Beijing Institute of GenomicsChinese Academy of Sciences and China National Center for BioinformationBeijingChina University of Chinese Academy of sciences BeijingChina Institute for stem Cell and Regeneration Chinese Academy of SciencesBeijingChina Aging Biomarker Consortium BeijingChina state Key Laboratory of stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijingChina Beijing Institute for stem Cell and Regenerative Medicine BeijingChina

The oral cavity is a complex physiological community encompassing a wide range of *** of oral microbiota can lead to various oral infectious diseases,such as periodontitis and tooth decay,and even affect systemic health,including brain aging and neurodegenerative *** studies have highlighted how oral microbes might be involved in brain aging and neurodegeneration,indicating potential avenues for intervention *** this review,we summarize clinical evidence demonstrating a link between oral microbes/oral infectious diseases and brain aging/neurodegenerative diseases,and dissect potential mechanisms by which oral microbes contribute to brain aging and *** also highlight advances in therapeutic development grounded in the realm of oral microbes,with the goal of advancing brain health and promoting healthy aging.

关键词： Alzheimer's disease brain aging multiple sclerosis neurodegeneration neurodegenerative diseases oral microbiota Parkinson's disease periodontitis bacteria Porphyromonas gingivalis

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ANALYsIs ON DYNAMIC CHARACTERIsTICs FOR FERROMAGNETIC CONDUCTING PLATEs IN A TRANsVERsE UNIFORM MAGNETIC FIELD

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Acta Mechanica solida sinica 2000年第1期13卷 9-16页

作者： Zheng, xJ liu, x Lanzhou Univ Dept Mech Lanzhou 730000 Peoples R China

In this paper, a set of basic equations for free vibration of ferromagnetic conducting plates in a transverse magnetic field are presented, in which the coupled effects of magnetization and eddy current on the mechanical behavior of the plate are included. Based on the quantitative analyses on the vibration frequency and the values of the critical magnetic field for several supporting conditions of the plate, the effects of the conductivity, the magnetic permeability, the thickness of the plate and supporting conditions on the vibration frequency of the plate and the critical magnetic field are discussed.

关键词： ferromagnetic conducting plate magnetoelasticity effect of eddy current vibration frequency stability

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Hierarchical structure and deformation behavior of a novel multicomponent β titanium alloy with ultrahigh strength

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Journal of Materials science & Technology 2022年第12期107卷 227-242页

作者： x.Li x.N.Wang K.liu G.H.Cao M.B.Li Z.s.Zhu s.J.Wu school of Materials science and Engineering Beihang UniversityBeijing 100191China Titanium Alloys Laboratory Beijing Institute of Aeronautical MaterialBeijing 100095China school of Materials science and Engineering Shanghai UniversityShanghai 200444China

Based on the general [Mo] equivalent criterion and d-electron orbital theory, a new ultrahigh-strength βtitanium alloy with eight major elements(Ti-4.5Al-6.5Mo-2Cr-2.6Nb-2Zr-2sn-1V, TB17) for industrial applications was developed. An ingot of five tons was successfully melted by thrice vacuum consumable arc melting. The microstructure and elements partitioning of different conditions were investigated systematically. The results suggest that the hierarchical structures of micro-scale first α phase(αf), nano-scale secondary α phase(αs), and ultrafine FCC substructures can be tailored by solution plus aging(sTA) heat treatment. The lateral and epitaxial growth of αfphase promotes the HCP-α to FCC substructure transformation with the help of elements partitioning during the aging process. Moreover, the element V, generally regarded as β stabilizer, is found to mainly concentrate in the Al-rich αfphase in this study probably due to its relatively lower content and the strong bonding energy of Al-V. The hierarchical structure has a strong interaction with dislocations, which contributes to achieve a superhigh strength of 1376 *** addition, the plastic strain is partitioned in the multi-scale precipitates(such as the α and FCC substructures) and β matrix, resulting in a considerable plasticity. TEM observation demonstrates that high density entangled dislocations at interfaces and mechanical twins exist in the sTA sample after tensile test. It can be deduced that both dislocation slipping and twinning mechanisms are present in this ***, TB17 alloy can serve as an excellent candidate for structural materials on aircrafts that require high strength and lightweight.

关键词： Titanium alloy Hierarchical structure Deformation behavior Ultrahigh strength Elements partitioning

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Towards the diffusion source cost reduction for NdFeB grain boundary diffusion process

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Journal of Materials science & Technology 2020年第1期36卷 50-54页

作者： H.x.Zeng Z.W.liu J.s.Zhang x.F.Liao H.Y.Yu school of Materials science and Engineering South China University of TechnologyGuangzhou 510640China

Aiming at improving the performance/cost ratio in grain boundary diffusion process(GBDP),the critical RE containing Pr-Al-Cu alloy,less expensive RE containing La-Al-Cu alloy and non-RE Al-Cu alloy were employed as the diffusion *** preliminary results show that the coercivity was successfully enhanced from 1000 kA/m to 1695,1156 and 1125 kA/m by Pr70Al20Cu10,La70Al20Cu10 and Al75Cu25(at.%) alloys diffusion,respectively,due to the formation of(Nd,Pr)-Fe-B,La2 O3 and c-Nd2 O3 phases respectively,after *** is also found that the corrosion resistance can be improved by Al-Cu diffusion due to the positive effects of Al and Cu elements in grain *** present results demonstrated the various coercivity enhancement mechanisms for the GBDP based on different diffusion sources,and provided feasible solutions for cost reduction of GBDP and NdFeB production by saving RE resource.

关键词： Grain boundary diffusion Cost reduction Coercivity Microstructure Corrosion resistance

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The substrates of Plk1, beyond the functions in mitosis

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Protein & Cell 2010年第11期1卷 999-1010页

作者： x.shawn liu Bing song xiaoqi liu Department of Biochemistry Purdue UniversityWest LafayetteIndiana 47907USA Department of Biological sciences Purdue UniversityWest LafayetteIndiana 47907USA Center for Cancer Research Purdue UniversityWest LafayetteIndiana 47907USA

Polo-like kinase 1(Plk1)is a key regulator of cell division in eukaryotic *** this short review,we briefly summarized the well-established functions modulated by Plk1 during *** mitosis,we focused mainly on the unexpected processes in which Plk1 emerges as a critical player,including microtubule dynamics,DNA replication,chromosome dynamics,p53 regulation,and recovery from the G2 DNA-damage *** discussion is mainly based on the critical substrates targeted by Plk1 during these cellular events and the functional significance associated with each phosphorylation event.

关键词： Polo-like kinase 1 phosphorylation substrates

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Microstructure evolution and hot deformation behavior of carbon nanotube reinforced 2009Al composite with bimodal grain structure

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Journal of Materials science & Technology 2021年第11期70卷 73-82页

作者： K.Ma Z.Y.liu s.Bi x.x.Zhang B.L.xiao Z.Y.Ma shi-changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of ScienceShenyang110016China school of Materials science and Engineering University of Science and Technology of China72 Wenhua RoadShenyang110016China school of Materials science and Engineering Guilin University of TechnologyGuilin541004China

The hot deformation behaviors of the bimodal carbon nanotube reinforced 2009Al(CNT/2009Al)composite were studied by establishing processing map and characterizing the microstructure *** results indicate that the grain size in the ultra-fine grained zones was stable during hot deformation,while the coarse grained zones were elongated with their long axis directions tending to be perpendicular to the compression *** temperature with high strain rate(LTHR),as well as high temperature with low strain rate(HTLR)could increase the length/width ratio of the coarse grained ***,LTHR and HTLR could cause the instable *** instable deformation at LTHR was induced by severe intragranular plastic deformation and the localized shear crack,while the instable deformation at HTLR resulted from the more deformation component at the coarse grained zones,and the micro-pore initiation due to CNT re-agglomeration at the boundaries between the coarse and the ultra-fine grained zones.

关键词： Carbon nanotube Bimodal Aluminum matrix composite Hot deformation Processing map

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