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The AGN Feedback in Compact Galaxies:On the Impact of a More Massive Central Black Hole

Research in Astronomy and Astrophysics 2023年第10期23卷 299-307页

作者： Yihuan Di feng Yuan Suoqing Ji Shanghai Astronomical Observatory Chinese Academy of SciencesShanghai 200030China University of Chinese Academy of Sciences Beijing 100049China

We conduct high-resolution hydrodynamical simulations using the MACER framework to investigate the interplay between the interstellar medium,active galactic nuclei(AGN)feedback and black hole(BH)feeding in a massive compact galaxy,with an emphasis on the impact of different central BH *** find that with a more massive central BH,high-speed outflows are more prominent,and the gas fraction in the compact galaxy is *** to the lower gas density and higher gas temperature,the compact galaxy with a more massive BH(MAS galaxy)remains predominantly single-phase with the cooling time t_(cool)■100t_(ff).In contrast,the compact galaxy with the reference BH mass(REF galaxy)maintains a higher gas fraction with a shorter cooling time,slightly more multiphase gas and less prominent *** further demonstrate that the difference in gas thermal states and kinematics is caused by the stronger AGN feedback in the compact galaxy with a more massive BH,where the AGN wind power is twice as much as that with the reference *** the AGN feedback efficiently suppresses the inflow rate and the BH feeding rate,the BH mass growth is significant in neither the compact galaxy with the reference BH nor that with the more massive BH,only by 24%and 11%of the initial BH mass,respectively,over the entire evolution time of 10 *** thus posit that without ex situ mass supply from mergers,the massive BHs in compact galaxies cannot grow significantly via gas accretion during the late phase,but might have already formed by the end of the rapid early phase of galaxy formation.

关键词： galaxies:active galaxies:evolution galaxies:nuclei (galaxies:)quasars:supermassive black holes

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The Middle-aged and Knowledge Workers: Demographic and Economic Changes in the Pearl River Delta, China

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Chinese Geographical Science 2022年第2期32卷 268-284页

作者： feng Pengfei Anna GROWE SHEN Yuming College of Resources Environment&TourismCapital Normal UniversityBeijing 100048China Institute of Geography Heidelberg UniversityBerliner Strafie 48D-69120 HeidelbergGermany

Demographic and economic development can be seen as two sides of one coin in the process of regional *** article deals with how economic and demographic changes influence the settlement structure and development of the Pearl River Delta(PRD)and lead to regionalization processes within the large *** aim of the study was to understand the interrelation between the three aspects:economic change,demographic change and change of spatial *** on population age and occupational data,spatial changes in demographic structure and economic activities from 2000 to 2010 were *** was found that the demographic and economic change reflected changing spatial patterns between the urban centers and the hinterland in the *** processes were apparent during the studied period in the hinterlands and the high-density areas of the *** one hand,the hinterlands in the PRD attracted more manufacturing activities,while the inner high-density areas experienced a decrease in manufacturing,associated with an increase in young labor in regions where workplaces that only required limited education *** the other hand,specialization in knowledge-intensive business services increased in the inner high-density areas,which also saw an increased share in the older *** finding suggests that increasing knowledge-intensive work correlates with higher age structures due to the longer formal education required and also the benefits knowledge workers accrue through experience and gained knowledge over ***,based on a transformation process,we tentatively conclude that the populations in high-density areas in the PRD became more middle-aged and were represented by more knowledge workers.

关键词： manufacturing knowledge-intensive business services(KIBS) economic change demographic change Pearl River Delta

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Words of the Editor-in-Chief——Academic discussion is an effective measure to promote scientific development

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Journal of Palaeogeography 2017年第3期6卷 219-223页

作者： Zeng-Zhao feng China University of Petroleum (Beijing)

Van Loon et al.＇s paper ＂The response of stromatolites to seismic shocks： Tomboliths from the Palaeoproterozoic Chaibasa Formation, E India＂ with a new term ＂tomboliths＂ and original viewpoints should be published, but some contents need to be discussed. Shanmugam＇s paper ＂The response of stromatolites to seismic shocks： Tomboliths from the Palaeoproterozoic Chaibasa Formation, E India： Discussion and liquefaction basics＂ pointed out some queries and problems about Van Loon et al.＇s paper. It is an academic discussion paper and should be published as well. However, some main problems, such as the new term＂tomboliths＂ and its origin of seismic shocks, ＂whether stromatolites or tomboliths are soft-sediment deformation structures or not＂, etc., also need to be discussed. Academic discussion is an effective measure to promote scientific development. The more thorough academic discussions are carried out regarding academic problems, the more scientific facts and truths will become clear. All participants in this discussion are contributors. It is active to carry out the policy of ＂A hundred flowers blossom and a hundred schools of thought contend＂ by our Journal of Palaeogeography.

关键词： Tomboliths Seismic shocks Stromatolitic bioclasts Stromatolitic gravels Stromatolites Softsediment deformation structures(SSDS) Academic discussion A hundred flowers blossom and a hundred schools of thought contend Geological practice

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A novel six-legged walking machine tool for in-situ operations

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Frontiers of Mechanical Engineering 2020年第3期15卷 351-364页

作者： Jimu LIU Yuan TIAN feng GAO State Key Laboratory of Mechanical System and Vibration School of Mechanical EngineeringShanghai Jiao Tong UniversityShanghai 200240China

The manufacture and maintenance of large parts in ships,trains,aircrafts,and so on create an increasing demand for mobile machine tools to perform in-situ ***,few mobile robots can accommodate the complex environment of industrial plants while performing machining *** study proposes a novel six-legged walking machine tool consisting of a legged mobile robot and a portable parallel kinematic machine *** kinematic model of the entire system is presented,and the workspace of different components,including a leg,the body,and the head,is analyzed.A hierarchical motion planning scheme is proposed to take advantage of the large workspace of the legged mobile platform and the high precision of the parallel machine *** repeatability of the head motion,body motion,and walking distance is evaluated through experiments,which is 0.11,1.0,and 3.4 mm,***,an application scenario is shown in which the walking machine tool steps successfully over a 250 mmhigh obstacle and drills a hole in an aluminum *** experiments prove the rationality of the hierarchical motion planning scheme and demonstrate the extensive potential of the walking machine tool for in-situ operations on large parts.

关键词： legged robot parallel mechanism mobile machine tool in-situ machining

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Microstructure evolution and deformation mechanism of amorphous/crystalline high-entropy-alloy composites

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Journal of Materials Science & Technology 2020年第19期54卷 14-19页

作者： Jia Li Haotian Chen Hui feng Qihong Fang Yong Liu feng Liu Hong Wu Peter K Liaw State Key Laboratory of Advanced Design and Manufacturing for Vehicle Body Hunan UniversityChangsha 410082China State Key Laboratory of Powder Metallurgy Central South UniversityChangsha 410083China Department of Materials Science and Engineering The University of TennesseeKnoxvilleTN 37996USA

High-entropy amorphous alloys present high hardness,but low tensile ***,deformation behavior of the amorphous/crystalline Fe Co Cr Ni high-entropy alloy(HEA)composite prepared by the previous experiment is investigated using atomic *** result shows the partial dislocations in the crystal HEA layer,and the formation of shear bands in the amorphous HEA layer occurs after *** strength of the amorphous/crystalline HEA composite reduces with increasing the thickness of the amorphous layer,agreeing with the previous *** coupled interaction between the crystal plasticity and amorphous plasticity in amorphous/crystalline HEA composites results in a more homogeneous redistribution of plastic deformation to cause interface hardening,due to the complex stress field in the amorphous *** current findings provide the insight into the deformation behavior of the amorphous/crystalline HEA composite at the nanoscale,which are useful for optimizing the structure of the HEA composite with high strength and good plasticity.

关键词： High-entropy alloy Amorphous/crystalline composite Deformation behavior Strengthening mechanism Molecular dynamics

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Exhausted T cells and epigenetic status

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Cancer Biology & Medicine 2020年第4期17卷 923-936页

作者： Ziqing Zeng feng Wei Xiubao Ren Department of Immunology Tianjin Medical University Cancer Institute and HospitalNational Clinical Research Center for CancerKey Laboratory of Cancer Prevention and TherapyTianjin's Clinical Research Center for CancerKey Laboratory of Cancer Immunology and BiotherapyTianjin 300060China Department of Biotherapy Tianjin Medical University Cancer Institute and HospitalNational Clinical Research Center for CancerKey Laboratory of Cancer Prevention and TherapyTianjin's Clinical Research Center for CancerKey Laboratory of Cancer Immunology and BiotherapyTianjin 300060China

Exhausted T cells are a group of dysfunctional T cells,which are present in chronic infections or *** most significant characteristics of exhausted T cells are attenuated effector cytotoxicity,reduced cytokine production,and upregulation of multiple inhibitory molecular receptors(e.g.,PD-1,TIM-3,and LAG-3).The intracellular metabolic changes,altered expression of transcription factors,and a unique epigenetic landscape constitute the exhaustion ***,researchers have made progress in understanding exhausted T cells,with the definition and identification of exhausted T cells changing from phenotypebased to being classified at the transcriptional and epigenetic *** studies have revealed that exhausted T cells can be separated into two subgroups,namely TCF1^(+)PD-1^(+)progenitor-like precursor exhausted cells and TCF1-PD-1^(+)terminally differentiated exhausted T ***,the progenitor-like precursor cell population may be a subset of T cells that can respond to *** have also found that TOX initiates and dominates the development of exhausted T cells at the transcriptional and epigenetic *** also maintains T cell survival and may affect decisions regarding treatment *** this review,we discuss the latest developments in T cell exhaustion in regards to definitions,subpopulations,development mechanisms,differences in diverse diseases,and treatment prospects for exhausted T ***,we hypothesize that the epigenetic state regulated by TOX might be the key point,which can determine the reversibility of exhaustion and the efficacy of immunotherapy.

关键词： T cell exhaustion TOX tumor immunity epigenetic landscape immunotherapy

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Analysis of ground deformation development and settlement prediction by air-boosted vacuum preloading

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Journal of Rock Mechanics and Geotechnical Engineering 2022年第1期14卷 272-288页

作者： Shuangxi feng Huayang Lei Cheng Lin Department of Civil Engineering Tianjin UniversityTianjin300354China Key Laboratory of Coast Civil Structure Safety of the ministry of Education Tianjin UniversityTianjin300354China Key Laboratory of Comprehensive Simulation of Engineering Earthquake and Urban-Rural Seismic Resilience China Earthquak AdministrationTianjin300354China Department of Civil Engineering University of VictoriaVictoriaBCV8P 5C2Canada

Vacuum preloading has been widely used to improve soft soils in coastal areas of *** increasing amount of evidence from field operations has shown that conventional vacuum preloading is prone to clogging in prefabricated vertical drains(PVDs)and demands a large volume of sand *** recent years,air-boosted vacuum preloading has been developed to overcome these limitations;however,this method still requires more data to verify its *** this study,a field test for air-boosted vacuum preloading was conducted,and a large-strain two-dimensional(2D)finite element(FE)model was developed and validated against the field test ***,a series of FE parametric analyses was performed to assess key factors,*** air injection pressure,the injection spacing,and the characteristics of cyclic injection,which affect the performance of the air-boosted vacuum *** results showed that the ground settlement and lateral displacement of the soils increased due to an increase in the injection pressure,a decrease in the injection spacing,or increases in the number and duration of the injection *** on the parametric analyses,an empirical formula for ground settlement prediction was proposed and compared with a case history reported in the literature,showing good agreement.

关键词： Air-boosted vacuum preloading Field test Numerical modeling Settlement Soft soils Ground improvement

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Some Theorems for Hypersurface of Randers Spaces

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Acta Mathematica Sinica,English Series 2020年第10期36卷 1125-1139页

作者： Jin Tang LI Jian feng ZHANG School of Mathematical Sciences Xiamen UniversityXiamen 361005P.R.China Department of Mathematics Lishui UniversityLishui 323000P.R.China

In this paper,we consider the hypersurfaces of Randers space with constant flag curvature.(1)Let(M^n+1,F)be a Randers–minkowski ***(M^n,F)is a hypersurface of(M^n+1,F)with constant flag curvature K=1,then we can prove that M is Riemannian.(2)Let(M^n+1,F)be a Randers space with constant flag ***(M,F)is a compact hypersurface of(M^n+1,F)with constant mean curvature|H|.Then a pinching theorem is established,which generalizes the result of[***.,120,1223–1229(1994)]from the Riemannian case to the Randers space.

关键词： Randers space hypersurfaces constant mean curvature constant flag curvature

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Experimental and numerical investigation on the dynamic shear failure mechanism of sandstone using short beam compression specimen

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第8期15卷 1911-1923页

作者： Zelin Yan feng Dai Yi Liu State Key Laboratory of Hydraulics and Mountain River Engineering College of Water Resource and HydropowerSichuan UniversityChengdu610065China

In this study,a novel testing method is proposed to characterize the dynamic shear property and failure mechanism of rocks by introducing the short beam compression(SBC)specimen into the split Hopkinson pressure bar(SHPB)***,the stress distribution of SBC specimen is comprehensively analyzed by finite element method(FEM),and the results show that the optimal notch separation ratio of SBC specimen is C/H?0.2 to achieve successful dynamic simple-shear ***,dynamic shear tests are conducted on sandstone using the SBC-SHPB *** careful pulse shaping technique,the dynamic force balance is guaranteed for SBC specimens,and the testing results show that the dynamic shear strength of sandstone is significantly *** the results of dynamic compression and tension tests,the failure envelopes of sandstone under different loading rates are obtained in the principle stress *** is found that the failure envelope of sandstone constantly expands outwards with increasing loading ***,the energy partition of SBC specimen is quantified by virtue of high-speed digital image correlation(DIC)*** results show that the kinetic energy portion is non-negligible,and the shear fracture energy increases with increasing loading *** addition,the microscopic shear cracking mechanism of SBC specimen is analyzed by the thin section observation:the intra-granular(TG)fracture of minerals dominates the dynamic shear failure of sandstone,and the portion of TG fracture increases with increasing loading *** study provides a convenient and reliable method to investigate the dynamic shear property and failure mechanism of rocks.

关键词： Dynamic shear property Short beam compression(SBC) Dynamic fracture energy Micro-cracking mechanism

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On Variational Principles of Metric Mean Dimension on Subsets in Feldman–Katok Metric

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Acta Mathematica Sinica,English Series 2024年第10期40卷 2519-2536页

作者： Kun Mei GAO Rui feng ZHANG School of Mathematics Hefei University of TechnologyHefei 230009P.R.China

In this paper,we studied the metric mean dimension in Feldman–Katok(FK for short)*** introduced the notions of FK-Bowen metric mean dimension and FK-Packing metric mean dimension on *** we established two variational... 详细信息

关键词： Metric mean dimension variational principle Feldman-Katok metric

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