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Particle Discontinuous Deformation Analysis of Static and Dynamic Crack Propagation in Brittle Material

Computer Modeling in Engineering & Sciences 2024年第5期139卷 2215-2236页

作者： Zediao Chen feng Liu State Key Laboratory of Hydraulic Engineering Intelligent Construction and Operation Tianjin UniversityTianjin300072China

Crack propagation in brittle material is not only crucial for structural safety evaluation,but also has a wideranging impact on material design,damage assessment,resource extraction,and scientific research.A thorough investigation into the behavior of crack propagation contributes to a better understanding and control of the properties of brittle materials,thereby enhancing the reliability and safety of both materials and structures.As an implicit discrete elementmethod,the Discontinuous Deformation Analysis(DDA)has gained significant attention for its developments and applications in recent years.Among these developments,the particle DDA equipped with the bonded particle model is a powerful tool for predicting the whole process of material from continuity to failure.The primary objective of this research is to develop and utilize the particle DDAtomodel and understand the complex behavior of cracks in brittle materials under both static and dynamic loadings.The particle DDA is applied to several classical crack propagation problems,including the crack branching,compact tensile test,Kalthoff impact experiment,and tensile test of a rectangular plate with a hole.The evolutions of cracks under various stress or geometrical conditions are carefully investigated.The simulated results are compared with the experiments and other numerical results.It is found that the crack propagation patterns,including crack branching and the formation of secondary cracks,can be well reproduced.The results show that the particle DDA is a qualified method for crack propagation problems,providing valuable insights into the fracture mechanism of brittle materials.

关键词： Discontinuous deformation analysis particle DDA crack propagation crack branching brittle materials

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A Trust Evaluation Mechanism Based on Autoencoder Clustering Algorithm for Edge Device Access of IoT

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Computers, Materials & Continua 2024年第2期78卷 1881-1895页

作者： Xiao feng Zheng Yuan Cyber Security Academy Beijing University of Posts and TelecommunicationsBeijing100876China Department of Cyberspace Security Beijing Electronic Science and Technology InstituteBeijing100070China State Grid Info-Telecom Great Power Science and Technology Co. Ltd.Beijing102211China

First,we propose a cross-domain authentication architecture based on trust evaluation mechanism,including registration,certificate issuance,and cross-domain authentication processes.A direct trust evaluation mechanism based on the time decay factor is proposed,taking into account the influence of historical interaction records.We weight the time attenuation factor to each historical interaction record for updating and got the new historical record data.We refer to the beta distribution to enhance the flexibility and adaptability of the direct trust assessment model to better capture time trends in the historical record.Then we propose an autoencoder-based trust clustering algorithm.We perform feature extraction based on autoencoders.Kullback leibler(KL)divergence is used to calculate the reconstruction error.When constructing a convolutional autoencoder,we introduce convolutional neural networks to improve training efficiency and introduce sparse constraints into the hidden layer of the autoencoder.The sparse penalty term in the loss function measures the difference through the KL divergence.Trust clustering is performed based on the density based spatial clustering of applications with noise(DBSCAN)clustering algorithm.During the clustering process,edge nodes have a variety of trustworthy attribute characteristics.We assign different attribute weights according to the relative importance of each attribute in the clustering process,and a larger weight means that the attribute occupies a greater weight in the calculation of distance.Finally,we introduced adaptive weights to calculate comprehensive trust evaluation.Simulation experiments prove that our trust evaluation mechanism has excellent reliability and accuracy.

关键词： Cross-domain authentication trust evaluation autoencoder

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A versatile model with three-dimensional triangular lattice for unconventional transport and various topological effects

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National Science Review 2024年第1期11卷 204-214页

作者： Jing-Yang You Gang Su Yuan Ping feng Department of Physics National University of Singapore Kavli Institute for Theoretical Sciences and CAS Center for Excellence in Topological Quantum Computation University of Chinese Academy of Sciences Centre for Advanced 2D Materials National University of Singapore

The finite Berry curvature in topological materials can induce many subtle phenomena, such as the anomalous Hall effect(AHE), spin Hall effect(SHE), anomalous Nernst effect(ANE), non-linear Hall effect(NLHE) and bulk photovoltaic effects. To explore these novel physics as well as their connection and coupling, a precise and effective model should be developed. Here, we propose such a versatile model—a 3D triangular lattice with alternating hopping parameters, which can yield various topological phases,including kagome bands, triply degenerate fermions, double Weyl semimetals and so on. We reveal that this special lattice can present unconventional transport due to its unique topological surface states and the aforementioned topological phenomena, such as AHE, ANE, NLHE and the topological photocurrent effect. In addition, we also provide a number of material candidates that have been synthesized experimentally with this lattice, and discuss two materials, including a non-magnetic triangular system for SHE, NLHE and the shift current, and a ferromagnetic triangular lattice for AHE and ANE. Our work provides an excellent platform, including both the model and materials, for the study of Berry-curvature-related physics.

关键词： three-dimensional triangular lattice different topological phases various topological effects Berry curvature

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The infection kinetics and transmission potential of two Guaico Culex viruses in Culex quinquefasciatus mosquitoes

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Virologica Sinica 2024年第2期39卷 228-234页

作者： Ru-Yi Chen Teng Zhao Jing-Jing Guo feng Zhu Na-Na Zhang Xiao-feng Li Hai-Tao Liu Fei Wang Yong-Qiang Deng Cheng-feng Qin College of Bioscience and Bioengineering Jiangxi Agricultural UniversityNanchang330045China State Key Laboratory of Pathogen and Biosecurity Beijing Institute of Microbiology and EpidemiologyAMMSBeijing100071China School of Life Sciences Southwest Forestry UniversityKunming650224China

Guaico Culex virus(GCXV)is a newly identified segmented Jingmenvirus from Culex spp.mosquitoes in Central and South America.The genome of GCXV is composed of four or five single-stranded positive RNA segments.However,the infection kinetics and transmission capability of GCXV in mosquitoes remain unknown.In this study,we used reverse genetics to rescue two GCXVs(4S and 5S)that contained four and five RNA segments,respectively,in C6/36 cells.Further in vitro characterization revealed that the two GCXVs exhibited comparable replication kinetics,protein expression and viral titers.Importantly,GCXV RNAs were detected in the bodies,salivary glands,midguts and ovaries of Culex quinquefasciatus at 4–10 days after oral infection.In addition,two GCXVs can colonize Cx.quinquefasciatus eggs,resulting in positive rates of 15%–35%for the second gonotrophic cycle.In conclusion,our results demonstrated that GCXVs with four or five RNA segments can be detected in Cx.quinquefasciatus eggs during the first and second gonotrophic cycles after oral infection.

关键词： Guaico Culex virus(GCXV) Jingmenvirus Culex quinquefasciatus Vertical transmission

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RNA m6A dynamic modification mediated by nucleuslocalized FTO is involved in follicular reserve

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Zoological Research 2024年第2期45卷 415-428页

作者： Jiao-Na Zhang Rui-Ting Wang Francesca-Gioia Klinger Shun-feng Cheng Wei Shen Xiao-feng Sun College of Life Sciences Key Laboratory of Animal Reproduction and Germplasm Enhancement in Universities of ShandongQingdao Agricultural UniversityQingdaoShandong 266109China Department of Biomedicine and Prevention University of Rome Tor VergataRome 00133Italy

In eukaryotic organisms,the most common internal modification of messenger RNA(m RNA)is N6-methyladenosine(m6A).This modification can be dynamically and reversibly controlled by specific enzymes known as m6A writers and erasers.The fat-mass and obesity-associated protein(FTO)catalyzes RNA demethylation and plays a critical role in various physiological and pathological processes.Our research identified dynamic alterations in both m6A and FTO during the assembly of primordial follicles,with an inverse relationship observed for m6A levels and nuclear-localized FTO expression.Application of Fto small interfering RNA(si RNA)altered the expression of genes related to cell proliferation,hormone regulation,and cell chemotaxis,and affected RNA alternative splicing.Overexpression of the full-length Fto gene led to changes in m6A levels,alternative splicing of Cdk5,cell proliferation,cell cycle progression,and proportion of primordial follicles.Conversely,overexpression of Fto lacking a nuclear localization signal(NLS)did not significantly alter m6A levels or primordial follicle assembly.These findings suggest that FTO,localized in the nucleus but not in the cytoplasm,regulates RNA m6A demethylation and plays a role in cell proliferation,cell cycle progression,and primordial follicle assembly.These results highlight the potential of m6A and its eraser FTO as possible biomarkers and therapeutic targets.

关键词： m6A FTO Ovary Primordial follicle assembly Alternative splicing

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Tailoring chaotic motion of microcavity photons in ray and wave dynamics by tuning the curvature of space

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Science China(Physics,Mechanics & Astronomy) 2024年第7期67卷 107-112页

作者： Wei Lin Yechun Ding Yongsheng Wang Peng Li Yanpeng Zhang feng Yun feng Li Key Laboratory for Physical Electronics and Devices of the Ministry of Education Shaanxi Key Lab of Information Photonic TechniqueSchool of Electronic Science and EngineeringFaculty of Electronic and Information EngineeringXi’an Jiaotong UniversityXi’an 710049China Department of Electrical and Photonics Engineering Technical University of DenmarkKgs.Lyngby 2800Denmark Center for Regenerative and Reconstructive Medicine Med-X InstituteThe First Affiliated Hospital of Xi’an Jiaotong UniversityXi’an 710061China Solid-State Lighting Engineering Research Center Xi’an Jiaotong UniversityXi’an 710049China

Microcavity photon dynamics in curved space is an emerging interesting area at the crossing point of nanophotonics,chaotic science,and non-Euclidean geometry.We report the sharp difference between the regular and chaotic motions of cavity photons subjected to the varying space curvature.While the island modes of regular motion rise in the phase diagram in the curved space,the chaotic modes show special mechanisms to adapt to the space curvature,including the fast diffusion of ray dynamics,and the localization and hybridization of the Husimi wavepackets among different periodic orbits.These observations are unique effects enabled by the combination of the chaotic trajectory,the wave nature of light,and the non-Euclidean orbital motion,and therefore make the system a versatile optical simulator for chaotic science under quantum mechanics in curved space-time.

关键词： microcavity chaotic motion curved space

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Multiscale observation in wide-spatial radar surveillance based on coherent FDA design

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Science China(Information Sciences) 2024年第2期67卷 232-252页

作者： Lei YU feng HE Yi SU College of Electronics Science National University of Defense Technology

Wide-spatial radar surveillance missions are challenging tasks, requiring an increased power budget and agility in transmission aimed at extracting information from multiple targets in different environments. These requirements necessitate high transmitting degrees of freedom(DOF) to achieve the objective of multiscale observation for specific tasks in specialized regions of interest. Herein, we exploit the multiscale observation ability in wide-spatial radar surveillance based on frequency diverse array(FDA)radar. The proposed method facilitates spatial anisotropic control of multiple radar resources, including the transmitting waveforms, beampattern, and bandwidth. By utilizing a coherent FDA radar, we offer principles for the selection of baseband waveforms, in addition to the quantitative design of the beampattern gain and optimal bandwidth from the perspective of detection. The feasibility of the proposed method is validated through numerical experiments, thus indicating the potential in wide-spatial radar surveillance. Moreover,this work can be regarded as a preliminary attempt to gauge the efficacy of the computational array, a novel academic concept.

关键词： multi-scale observation wide-spatial surveillance frequency diverse array (FDA) beampattern synthesis frequency diversity gain computational array

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Improved observation of colonized roots reveals the regulation of arbuscule development and senescence by drought stress in the arbuscular mycorrhizae of citrus

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Horticultural Plant Journal 2024年第2期10卷 425-436页

作者： Xilong Yin Wei Zhang Zengwei feng Guangda feng Honghui Zhu Qing Yao College of Horticulture South China Agricultural UniversityKey Laboratory of Biology and Genetic Improvement of Horticultural Crops(South China)Ministry of Agriculture and Rural AffairsGuangdong Province Key Laboratory of Microbial Signals and Disease ControlGuangzhouGuangdong 510642China Key Laboratory of Agricultural Microbiomics and Precision Application Ministry of Agriculture and Rural AffairsGuangdong Provincial Key Laboratory of Microbial Culture Collection and ApplicationKey Laboratory of Agricultural MicrobiomicsState Key Laboratory of Applied Microbiology Southern ChinaGuangdong Microbial Culture Collection Center(GDMCC)Institute of MicrobiologyGuangdong Academy of SciencesGuangzhouGuangdong 510070China

Citrus is the typical mycorrhizal fruit tree species establishing symbiosis with arbuscular mycorrhizal (AM) fungi. However, arbuscule development and senescence in colonized citrus roots, especially in response to drought stress, remain unclear, which is mainly due to the difficulty in clearing and staining lignified roots with the conventional method. Here, we improved the observation of colonized roots of citrus plants with the sectioning method, which enabled the clear observation of AM fungal structures. Furthermore, we investigated the effects of one week of drought stress on arbuscule development and senescence with the sectioning method. Microscopy observations indicated that drought stress significantly decreased mycorrhizal colonization (F%and M%) although it did not affect plant growth performance. Fluorescence probes (WGA 488 and/or Nile red) revealed that drought stress inhibited arbuscule development by increasing the percentage of arbuscules at the early stage and decreasing the percentages of arbuscules at the midterm and mature stages. Meanwhile, drought stress accelerated arbuscule senescence, which was characterized by the increased accumulation of neutral lipids. Overall, the sectioning method developed in this study enables the in-depth investigation of arbuscule status, and drought stress can inhibit arbuscule development but accelerate arbuscule senescence in the colonized roots of citrus plants. This study paves the way to elaborately dissecting the arbuscule dynamics in the roots of fruit tree species in response to diverse abiotic stresses.

关键词： Arbuscular mycorrhizae Citrus Drought stress Arbuscule development Arbuscule senescence Fruit tree species

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From non-carbon host toward carbon-free lithium-sulfur batteries

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Nano Research 2024年第3期17卷 1337-1365页

作者： Yanqi feng Hui Liu Qiongqiong Lu School of Materials Science and Engineering Shaanxi Key Laboratory of Green Preparation and Functionalization for Inorganic MaterialsShaanxi University of Science and TechnologyXi’an 710021China Institute of Materials Henan Key Laboratory of Advanced Conductor MaterialsHenan Academy of SciencesZhengzhou 450046China Leibniz Institute for Solid State and Materials Research(IFW)Dresden e.V. Helmholtzstraβe 2001069 DresdenGermany School of Materials&Environment Engineering Chengdu Technological UniversityChengdu 611730China

Lithium-sulfur(Li-S)batteries with advantages of high energy densities(2600 Wh·kg^(-1)/2800 Wh·L^(-1))and sulfur abundance are regarded as promising candidates for next-generation high-energy batteries.However,the conventional carbon host used in sulfur cathodes suffers from poor chemical adsorption towards Li-polysulfides(LPS)in liquid electrolyte and sluggish redox kinetics,leading to low capacity and rate capability.Besides,carbon host used in Li metal anode with the intrinsic property of poor lithiophilicity and high Li-nucleation barrier gives rise to uncontrollable dendrite growth and further battery failure.Therefore,non-carbon hosts with chemical adsorption toward LPS and catalytic activity for accelerating LPS redox conversion as well as lithiophilic property for guiding uniform Li deposition are proposed and demonstrated a high efficiency in both sulfur cathodes and Li metal anodes.In this review,the principle and challenges of Li-S batteries are first presented,then recent work using non-carbon hosts in Li-S batteries is summarized comprehensively,and the mechanism of non-carbon host in improving sulfur utilization and stabilizing Li metal anode is discussed in detail.Furthermore,remaining challenges and outlook on the implementation of non-carbon host for practical carbon-free Li-S batteries are also provided.

关键词： sulfur cathode Li metal anode polysulfides adsorption catalytic effect Li dendrite carbon-free lithium-sulfur batteries

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Intersection theory rules symbology

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Science China(Physics,Mechanics & Astronomy) 2024年第2期67卷 93-104页

作者： Jiaqi Chen Bo feng Lilin Yang Beijing Computational Science Research Center Beijing 100084China Zhejiang Institute of Modern Physics School of PhysicsZhejiang UniversityHangzhou 310027China Peng Huanwu Center for Fundamental Theory Hefei 230026China

We propose a novel method to determine the structure of symbols for any family of polylogarithmic Feynman integrals.Using the d log-bases and simple formulas for the leading order and next-to-leading contributions to the intersection numbers,we give a streamlined procedure to compute the entries in the coefficient matrices of canonical differential equations,including the symbol letters and the rational coefficients.We also provide a selection rule to decide whether a given matrix element must be zero.The symbol letters are deeply related to the poles of the integrands and also have interesting connections to the geometry of Newton polytopes.Our method can be applied to many cutting-edge multi-loop calculations.The simplicity of our results also hints at the possible underlying structure in perturbative quantum field theories.

关键词： scattering amplitude Feynman integral symbology

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