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Life forms affect beta-diversity patterns of larch forests in China

Plant Diversity 2024年第1期46卷 49-58页

作者： Wenjing Fang Qiong Cai Chengjun Ji Jiangling zhu Zhiyao Tang Jingyun Fang School of ecology and environmental Science Yunnan UniversityKunming 650091China Department of ecology College of Urban and Environmental Sciencesand Key Laboratory for Earth Surface Processes of the Ministry of EducationPeking UniversityBeijing 100871China

Beta-diversity reflects the spatial changes in community species composition which helps to understand how communities are assembled and biodiversity is formed and maintained. Larch(Larix) forests, which are coniferous forests widely distributed in the mountainous and plateau areas in North and Southwest China, are critical for maintaining the environmental conditions and species diversity. Few studies of larch forests have examined the beta-diversity and its constituent components(species turnover and nestedness-resultant components). Here, we used 483 larch forest plots to determine the total betadiversity and its components in different life forms(i.e., tree, shrub, and herb) of larch forests in China and to evaluate the main drivers that underlie this beta-diversity. We found that total betadiversity of larch forests was mainly dependent on the species turnover component. In all life forms,total beta-diversity and the species turnover component increased with increasing geographic, elevational, current climatic, and paleoclimatic distances. In contrast, the nestedness-resultant component decreased across these same distances. Geographic and environmental factors explained 20%-25% of total beta-diversity, 18%-27% of species turnover component, and 4%-16% of nestedness-resultant component. Larch forest types significantly affected total beta-diversity and species turnover component. Taken together, our results indicate that life forms affect beta-diversity patterns of larch forests in China, and that beta-diversity is driven by both niche differentiation and dispersal limitation. Our findings help to greatly understand the mechanisms of community assemblies of larch forests in China.

关键词： Beta-diversity Species turnover Nestedness-resultant Geographic distance Climatic distance Larch forest

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Automatic detection and assessment of crack development in ultra-high performance concrete in the spatial and Fourier domains

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Frontiers of Structural and Civil engineering 2024年第3期18卷 350-364页

作者： Jixing CAO Yao ZHANG Haijie He Weibing PeNG Weigang ZHAO Zhiguo YAN Hehua zhu School of Safety engineering and emergency Management Shijiazhuang Tiedao UniversityShijiazhuang 050043China College of Civil engineering and Architecture Zhejiang UniversityHangzhou 310058China College of Civil and Architectural engineering Taizhou UniversityTaizhou 318000China College of Civil engineering and Architecture Zhejiang University of TechnologyHangzhou 310014China Department of Geotechnical engineering Tongji UniversityShanghai 200092China

Automatic detection and assessment of surface cracks are beneficial for understanding the mechanical performance of ultra-high performance concrete(UHPC).This study detects crack evolution using a novel dynamic mode decomposition(DMD)*** this method,the sparse matrix‘determined’from images is used to reconstruct the foreground that contains cracks,and the global threshold method is adopted to extract the crack *** application of the DMD method to the three-point bending test demonstrates the efficiency in inspecting cracks with high ***,the geometric features,including the area and its projection in two major directions,are evaluated over *** relationship between the geometric properties of cracks and load-displacement curves of UHPC is *** to the irregular shape of cracks in the spatial domain,the cracks are then transformed into the Fourier domain to assess their *** indicate that crack patterns in the Fourier domain exhibit a distinct concentration around a central ***,the power spectral density of cracks exhibits an increasing trend over *** investigation into crack evolution in both the spatial and Fourier domains contributes significantly to elucidating the mechanical behavior of UHPC.

关键词： dynamic mode decomposition ultra-high performance concrete crack detection geometric features Fourier domain

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Optical Transient Source AT2021lfa:A Possible“Dirty Fireball”

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Research in Astronomy and Astrophysics 2024年第4期24卷 124-133页

作者： Xue-Mei Ye Da-Ming Wei Yi-Ming zhu Zhi-Ping Jin Key Laboratory of Dark Matter and Space Astronomy Purple Mountain ObservatoryChinese Academy of SciencesNanjing 210023China School of Astronomy and Space Science University of Science and Technology of ChinaHefei 230026China National Astronomical Observatories/Nanjing Institute of Astronomical Optics&Technology Chinese Academy of SciencesNanjing 210042China CAS Key Laboratory of Astronomical Optics&Technology Nanjing Institute of Astronomical Optics&TechnologyNanjing 210042China

AT2021lfa,also known as ZTF21aayokph,was detected by the Zwicky Transient Facility on 2021 May 4,a 05:34:48 ***-up observations were conducted using a range of ground-based optical telescopes,as wel as Swift/XRT and VLA ***2021lfa is classified as an“orphan afterglow”candidate due to its rapid flux decline and its reddened color(g-r=0.17±0.14 mag).For an optical transient source without promp gamma-ray detection,one key point is to determine its burst *** we measure the burst time through fitting the initial bump feature of AT2021lfa and obtain its burst time as 2021 May 3,at 22:09:50 *** afterglowpy,we model the multi-band afterglow of AT2021lfa and find that the standard model canno reproduce the late radio observations *** that the microphysical parameters ε_(e),ε_(B)(the energy fraction given to electrons and magnetic field),andξN(the fraction of accelerated electrons)may vary with time we then model the afterglow of AT2021lfa taking into account the temporal evolution of the physical parameters ε_(e),ε^(B),and ξ_(N) and find in this case the multi-wavelength observations can be reproduced *** initial Lorentz factor of AT2021lfa can be estimated from the peak time of the early afterglow,which yields a value of about 18 suggesting that AT2021lfa should be classified as a“dirty fireball.”From the upper limit for the prompt emission energy of AT2021lfa,we obtain that the radiation efficiency is less than 0.02%,which is much smaller than that of ordinary gamma-ray bursts(GRBs).It is also interesting that the fitted values of jet angle and viewing angle are very large,θ_(c)~0.66 rad,θ_(v)~0.53 rad,which may lead to the low Lorentz factor and radiation *** compared with GRB afterglow samples,it is evident that the onset bump timescale of AT2021lfa satisfies the empirical relationships observed in GRB ***,the luminosity of AT2021lfa falls within the range of observations for GRB samples;howeve

关键词： gamma-rays:ISM methods:numerical radiation mechanisms:non-thermal

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A method to interpret fracture aperture of rock slope using adaptive shape and unmanned aerial vehicle multi-angle nap-of-the-object photogrammetry

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Journal of Rock Mechanics and Geotechnical engineering 2024年第3期16卷 924-941页

作者： Mingyu Zhao Shengyuan Song Fengyan Wang Chun zhu Dianze Liu Sicong Wang College of Construction engineering Jilin UniversityChangchun130026China College of Geo-exploration Science and Technology Jilin UniversityChangchun130026China Institute of engineering Geology and Geohazards Hohai UniversityNanjing210098China

The aperture of natural rock fractures significantly affects the deformation and strength properties of rock masses,as well as the hydrodynamic properties of fractured rock *** conventional measurement methods are inadequate for collecting data on high-steep rock slopes in complex mountainous *** study establishes a high-resolution three-dimensional model of a rock slope using unmanned aerial vehicle(UAV)multi-angle nap-of-the-object photogrammetry to obtain edge feature points of *** opening morphology is characterized using coordinate projection and *** central axis is determined using vertical measuring lines,allowing for the interpretation of aperture of adaptive fracture *** feasibility and reliability of the new method are verified at a construction site of a railway in southeast Tibet,*** study shows that the fracture aperture has a significant interval effect and size *** optimal sampling length for fractures is approximately 0.5e1 m,and the optimal aperture interpretation results can be achieved when the measuring line spacing is 1%of the sampling *** fractures in the study area generally have larger apertures than shear fractures,and their tendency to increase with slope height is also greater than that of shear *** aperture of tensile fractures is generally positively correlated with their trace length,while the correlation between the aperture of shear fractures and their trace length appears to be *** of different orientations exhibit certain differences in their distribution of aperture,but generally follow the forms of normal,log-normal,and gamma *** study provides essential data support for rock and slope stability evaluation,which is of significant practical importance.

关键词： Unmanned aerial vehicle(UAV) photogrammetry High-steep rock slope Fracture aperture Interval effect Size effect Parameter interpretation

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Construction of Pd-doped RuO_(2) nanosheets for efficient and stable acidic water oxidation

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Green energy & environment 2024年第6期9卷 937-948页

作者： Yibo Liu Xing Hu Chenxi Liu Shan zhu Kezhu Jiang Feng Liu Shijian Zheng Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology College of Materials Science and EngineeringHebei University of TechnologyTianjin300401China Yunnan Precious Metals Lab Co. LTDKunming650100China

RuO_(2) has been considered a potential alternative to commercial IrO_(2) for the oxygen evolution reaction(OeR)due to its superior intrinsic ***,its inherent structure dissolution in acidic environments restricts its commercial *** this study,we report a novel Pd-doped ruthenium oxide(Pd–RuO_(2))nanosheet catalyst that exhibits improved activity and stability through a synergistic effect of Pd modulation of Ru electronic structure and the two-dimensional *** catalyst exhibits excellent performance,achieving an overpotential of only 204 mVat a current density of 10 mA cm^(-2).Impressively,after undergoing 8000 cycles of cyclic voltammetry testing,the overpotential merely decreased by 5 *** PeM electrolyzer with Pd0.08Ru0.92O_(2) as an anode catalyst survived an almost 130 h operation at 200 mA cm^(-2).To elucidate the underlying mechanisms responsible for the enhanced stability,we conducted an X-ray photoelectron spectroscopy(XPS)analysis,which reveals that the electron transfer from Pd to Ru effectively circumvents the over-oxidation of Ru,thus playing a crucial role in enhancing the catalyst's ***,density functional theory(DFT)calculations provide compelling evidence that the introduction of Pd into RuO_(2) effectively modulates electron correlations and facilitates the electron transfer from Pd to Ru,thereby preventing the overoxidation of ***,the application of the two-dimensional structure effectively inhibited the aggregation and growth of nanoparticles,further bolstering the structural integrity of the catalyst.

关键词： Oxygen evolution reaction Pd-doped ruthenium oxide Two-dimensional structure electron transfer Stability

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Reconfigurable memlogic long wave infrared sensing with superconductors

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Light(Science & Applications) 2024年第5期13卷 908-920页

作者： Bingxin Chen Huanyi Xue Hong Pan Liping zhu Xiaomi Yan Jingzhe Wang Yanru Song Zhenghua An State Key Laboratory of Surface Physics and Institute for Nanoelectronic Devices and Quantum Computing Department of PhysicsFudan UniversityShanghai 200438China. ShanghaiTech Quantum Device Lab ShanghaiTech UniversityShanghai 201210China. Shanghai Qi Zhi Institute 41th FloorAI TowerNo.701 Yunjin RoadXuhui DistrictShanghai 200232China. Yiwu Research Institute of Fudan University Chengbei RoadYiwu City 322000 ZhejiangChina. Zhangjiang Fudan International Innovation Center Fudan UniversityShanghai 201210China

Optical sensors with in-cell logic and memory capabilities offer new horizons in realizing machine vision beyond von Neumann architectures and have been attempted with two-dimensional materials,memristive oxides,phasechanging materials *** the unparalleled performance of superconductors with both quantum-limited optical sensitivities and ultra-wide spectrum coverage,here we report a superconducting memlogic long-wave infrared sensor based on the bistability in hysteretic superconductor-normal phase *** cooperatively by electrical and optical pulses,the device offers deterministic in-sensor switching between resistive and superconducting(hence dissipationless)states with persistence>105 *** results in a resilient reconfigurable memlogic system applicable for,e.g.,encrypted ***,a high infrared sensitivity at 12.2μm is achieved through its in-situ metamaterial perfect absorber *** work opens the avenue to realize all-in-one superconducting memlogic sensors,surpassing biological retina capabilities in both sensitivity and wavelength,and presents a groundbreaking opportunity to integrate visional perception capabilities into superconductor-based intelligent quantum machines.

关键词： wave superconductor quantum

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experimental Study on Soot Suppression of Acetylene Diffusion Flame by Acoustic-excited Oscillation in Rijke-Type Burner

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Journal of Thermal Science 2024年第1期33卷 235-248页

作者： zhu Yibin GUO Hui SUO Yan'ge WU Minle Ye Yanghui LI Guoneng ZHANG Zhiguo School of Mechanical and energy engineering Zhejiang University of Science and TechnologyHangzhou 310023China

This work reports that the flame oscillation induced by acoustic excitation can effectively suppress soot generation in Rijke-type *** the acoustic frequency is close to the natural frequency of the burner system,it can produce resonance resulting in intense oscillation of the *** relationship between the soot suppression efficiency and the acoustic field of standing wave at different flame positions is *** with that under self-excited oscillation,when there is external forced acoustic force introduced to the flame,oscillation combustion occurred in a lager zone in the glass *** fundamental cause of different soot suppression efficiency at different positions is that the standing wave acoustic field causes the particles to move at different speeds in different positions of the glass *** axial particle velocity difference results in the formation of acoustic vortexes and the change of the flame *** high particle velocity causes the air in the glass tube to turn into the turbulent condition and make the flame temperature *** results show that the surface growth rate of soot is reduced,while the oxidation rate of soot is enhanced,which result in the soot suppression under acoustic *** study can provide some reference for the practical application of oscillate combustion in soot suppression.

关键词： soot suppression acetylene diffusion flame acoustic-excited oscillation standing wave

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High-throughput calculations combining machine learning to investigate the corrosion properties of binary Mg alloys

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Journal of Magnesium and Alloys 2024年第4期12卷 1406-1418页

作者： Yaowei Wang Tian Xie Qingli Tang Mingxu Wang Tao Ying Hong zhu Xiaoqin Zeng University of Michigan-Shanghai Jiao Tong University Joint Institute Shanghai Jiao Tong University200240ShanghaiChina State Key Laboratory of Metal Matrix Composites Shanghai Jiao Tong UniversityShanghai200240China

Magnesium(Mg)alloys have shown great prospects as both structural and biomedical materials,while poor corrosion resistance limits their further *** this work,to avoid the time-consuming and laborious experiment trial,a high-throughput computational strategy based on first-principles calculations is designed for screening corrosion-resistant binary Mg alloy with intermetallics,from both the thermodynamic and kinetic *** stable binary Mg intermetallics with low equilibrium potential difference with respect to the Mg matrix are firstly ***,the hydrogen adsorption energies on the surfaces of these Mg intermetallics are calculated,and the corrosion exchange current density is further calculated by a hydrogen evolution reaction(HeR)kinetic *** intermetallics,e.g.Y_(3)Mg,Y_(2)Mg and La_(5)Mg,are identified to be promising intermetallics which might effectively hinder the cathodic ***,machine learning(ML)models are developed to predict Mg intermetallics with proper hydrogen adsorption energy employing work function(W_(f))and weighted first ionization energy(WFIe).The generalization of the ML models is tested on five new binary Mg intermetallics with the average root mean square error(RMSe)of 0.11 *** study not only predicts some promising binary Mg intermetallics which may suppress the galvanic corrosion,but also provides a high-throughput screening strategy and ML models for the design of corrosion-resistant alloy,which can be extended to ternary Mg alloys or other alloy systems.

关键词： Mg intermetallics Corrosion property High-throughput Density functional theory Machine learning

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A Deep Neural Collaborative Filtering Based Service Recommendation Method with Multi-Source Data for Smart Cloud-edge Collaboration Applications

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Tsinghua Science and Technology 2024年第3期29卷 897-910页

作者： Wenmin Lin Min zhu Xinyi Zhou Ruowei Zhang Xiaoran Zhao Shigen Shen Lu Sun Alibaba Business School Hangzhou Normal UniversityHangzhou 311121China Blockchain Laboratory of Agricultural Vegetables Weifang University of Science and TechnologyShouguang 262700China School of Computer Science Qufu Normal UniversityRizhao 276827China School of Information engineering Huzhou UniversityHuzhou 313000China

Service recommendation provides an effective solution to extract valuable information from the huge and ever-increasing volume of big data generated by the large cardinality of user ***,the distributed and rich multi-source big data resources raise challenges to the centralized cloud-based data storage and value mining approaches in terms of economic cost and effective service recommendation *** view of these challenges,we propose a deep neural collaborative filtering based service recommendation method with multi-source data(i.e.,NCF-MS)in this paper,which adopts the cloud-edge collaboration computing paradigm to build recommendation *** specifically,the Stacked Denoising Auto encoder(SDAe)module is adopted to extract user/service features from auxiliary user profiles and service *** Multiple Layer Perceptron(MLP)module is adopted to integrate the auxiliary user/service features to train the recommendation ***,we evaluate the effectiveness of the NCF-MS method on three public *** experimental results show that our proposed method achieves better performance than existing methods.

关键词： deep neural collaborative filtering multi-source data cloud-edge collaboration application stackeddenoising auto encoder multiple layer perceptron

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Taiji-TianQin-LISA network:Precisely measuring the Hubble constant using both bright and dark sirens

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 59-77页

作者： Shang-Jie Jin Ye-zhu Zhang Ji-Yu Song Jing-Fei Zhang Xin Zhang Key Laboratory of Cosmology and Astrophysics(Liaoning)&College of Sciences Northeastern UniversityShenyang 110819China Key Laboratory of Data Analytics and Optimization for Smart Industry(Ministry of education) Northeastern UniversityShenyang 110819China National Frontiers Science Center for Industrial Intelligence and Systems Optimization Northeastern UniversityShenyang 110819China

In the coming decades,the space-based gravitational-wave(GW)detectors such as Taiji,TianQin,and LISA are expected to form a network capable of detecting millihertz GWs emitted by the mergers of massive black hole binaries(MBHBs).In this work,we investigate the potential of GW standard sirens from the Taiji-TianQin-LISA network in constraining cosmological *** the optimistic scenario in which electromagnetic(eM)counterparts can be detected,we predict the number of detectable bright sirens based on three different MBHB population models,i.e.,popⅢ,Q3d,and *** results show that the TaijiTianQin-LISA network alone could achieve a constraint precision of 0.9%for the Hubble constant,meeting the standard of precision ***,the Taiji-TianQin-LISA network could effectively break the cosmological parameter degeneracies generated by the CMB data,particularly in the dynamical dark energy *** combined with the CMB data,the joint CMB+Taiji-TianQin-LISA data offerσ(w)=0.036 in the wCDM model,which is close to the latest constraint result obtained from the CMB+SN *** also consider a conservative scenario in which eM counterparts are not *** to the precise sky localizations of MBHBs by the Taiji-TianQin-LISA network,the constraint precision of the Hubble constant is expected to reach 1.2%.In conclusion,the GW standard sirens from the Taiji-TianQin-LISA network will play a critical role in helping solve the Hubble tension and shedding light on the nature of dark energy.

关键词： space-based gravitational wave detection standard sirens the Taiji-TianQin-LISA network the Hubble constant dark energy

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