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Effect of burial depth of a new tunnel on the seismic response of an existing tunnel

Earthquake Engineering and Engineering Vibration 2024年第4期23卷 863-882页

作者： Ma Runbo Cao Qikun Lu Shasha Zhao Dongxu Zhang Yanan xu hong College of Civil Engineering Liaoning Technical UniversityFuxin 123000China Key Laboratory of Urban Security and Disaster Engineering of Ministry of Education Beijing University of TechnologyBeijing 100124China

Burial depth is a crucial factor affecting the forces and deformation of tunnels during *** key issue is a lack of understanding of the effect of a change in the buried depth of a single-side tunnel on the seismic response of a double-tunnel *** this study,shaking table tests were designed and performed based on a tunnel under construction in Dalian,*** models were established using the equivalent linear method combined with ABAQUS finite element software to analyze the seismic response of the interacting *** results showed that the amplification coefficient of the soil acceleration did not change evidently with the burial depth of the new tunnel but decreased as the seismic amplitude *** addition,the existing tunnel acceleration,earth pressure,and internal force were hardly affected by the change in the burial depth;for the new tunnel,the acceleration and internal force decreased as the burial depth increased,while the earth pressure *** shows that the earth pressure distribution in a double-tunnel system is relatively complex and mainly concentrated on the arch spandrel and arch springing of the relative ***,when the horizontal clearance between the center of the two tunnels was more than twice the sum of the radius of the outer edges of the two tunnels,the change in the burial depth of the new tunnel had little effect on the existing one,and the tunnel structure was deemed *** results provide a preliminary understanding and reference for the seismic performance of a double-tunnel system.

关键词： burial depth new tunnel existing tunnel seismic response shaking table tests numerical simulations

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The interaction between temperature and precipitation on the potential distribution range of Betula ermanii in the alpine treeline ecotone on the Changbai Mountain

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Forest Ecosystems 2024年第1期11卷 42-51页

作者： Yu Cong Yongfeng Gu Wen J.Wang Lei Wang Zhenshan xue Yingyi Chen Yinghua jin Jiawei xu Mai-He Li hong S.He Ming Jiang Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun 130102China Key Laboratory of Geographical Processes and Ecological Security in Changbai Mountains Ministry of EducationSchool of Geographical SciencesNortheast Normal UniversityChangchun 130024China School of Natural Resources University of MissouriColumbiaMO 65211USA Swiss Federal Institute for Forest Snow and Landscape Research WSLCH-8903 BirmensdorfSwitzerland School of Life Science Hebei UniversityBaoding 071000China

Alpine treeline ecotones are highly sensitive to climate *** low temperature-determined alpine treeline is expected to shift upwards in response to global ***,little is known about how temperature interacts with other important factors to influence the distribution range of tree species within and beyond the alpine treeline ***,we used a GF-2 satellite image,along with bioclimatic and topographic variables,to develop an ensemble suitable habitat model based on the species distribution modeling algorithms in *** investigated the distribution of suitable habitats for *** under three climate change scenarios(i.e.,low(SSP126),moderate(SSP370)and extreme(SSP585)future emission trajectories)between two consecutive time periods(i.e.,current-2055,and 2055-2085).By 2055,the potential distribution range of *** will expand under all three climate *** medium and high suitable areas will decline under SSP370 and SSP585scenarios from 2055 to ***,under the three climate scenarios,the uppermost altitudes of low suitable habitat will rise to 2,329 m a.s.l.,while the altitudes of medium and high suitable habitats will fall to 2,201 and2,051 m *** 2085,*** promotes the expansion of *** distribution range in Changbai Mountain,and this expansion will be modified by precipitation as climate warming *** interaction between temperature and precipitation plays a significant role in shaping the potential distribution range of *** in the alpine treeline *** study reveals the link between environmental factors,habitat distribution,and species distribution in the alpine treeline ecotone,providing valuable insights into the impacts of climate change on high-elevation vegetation,and contributing to mountain biodiversity conservation and sustainable development.

关键词： Biomod2 Birch Climate change Climate scenarios Habitat suitability Range shift Treeline species

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Preventive effects of Bifidobacterium lactis Probio-M8 on ovalbumin-induced food allergy in mice

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Food Science and Human Wellness 2024年第4期13卷 2346-2352页

作者： Jialu Shi Yan xu Cheng Liu Shizhi Wang jin Wang Vijaya Raghavan Key Laboratory of Environmental Medicine and Engineering Ministry of Educationand Department of Nutrition and Food HygieneSchool of Public HealthSoutheast UniversityNanjing 210009China Department of Bioresource Engineering Faculty of Agricultural and Environmental SciencesMcGill UniversitySainte-Anne-de-BellevueQC H9X3V9Canada

Food allergy is a significant public health concern *** probiotics have been found to enhance food allergy by regulating immune-microbe interactions in animal models and ***,the effects of Bifidobacterium lactis Probio-M8 on food allergy have not been thoroughly *** present study examined the anti-allergic properties of Probio-M8,particularly in relation to immune response and gut microbiota *** demonstrate that oral administration of Probio-M8 effectively mitigated the allergy symptoms triggered by ovalbumin(OVA)by ameliorating the morphological damage in the jejunum,reducing OVA-specific IgE and histamine levels in the serum,and suppressing Th2 cytokines(interleukin(IL)4 and IL-13)while increasing Th1 cytokines(interferon(IFN)γ)and regulatory T(Treg)cytokines(IL-10 and transforming growth factor(TGF)β1)in the culture supernatants of splenic ***,Probio-M8 effectively altered the diversity and composition of gut microbiota,particularly the relative abundances of Akkermansia_muciniphila in OVA-induced *** to the OVA group,the Probio-M8 group showed a decrease in the relative abundance of Akkermansia_*** conclusion,Probio-M8 demonstrates the potential to alleviate food allergy by regulating the Th1/Th2 response and modulating gut microbiota,thereby offering a novel therapeutic strategy for patients with food allergy.

关键词： Food allergy Bifidobacterium lactis Probio-M8 T cell immune response Gut microbiota

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Searching for plant NLR immune receptors conferring resistance to potyviruses

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The Crop Journal 2024年第1期12卷 28-44页

作者： Xin hong Shufen Li Xiaofei Cheng Haijian Zhi jinlong Yin Kai xu Jiangsu Key Laboratory for Microbes and Functional Genomics Jiangsu Engineering and Technology Research Center for MicrobiologyCollege of Life SciencesNanjing Normal UniversityNanjing 210023JiangsuChina College of Plant Protection Northeast Agricultural UniversityHarbin 150030HeilongjiangChina National Center for Soybean Improvement National Key Laboratory for Crop Genetics and Germplasm EnhancementKey Laboratory of Biology and Genetic Improvement of Soybean-Ministry of AgricultureNanjing Agricultural UniversityNanjing 210095JiangsuChina

To fight against invasion by pathogens,plants have evolved an elaborate innate immune system,of which the nucleotide-binding domain leucine-rich repeat-containing receptor(NLR)acts as the sensor and immune ***,comprising one of the largest genera of plant viruses,cause severe crop yield losses *** crop resistance to potyviruses can be used in breeding and plant transgenesis to control disease *** review summarizes achievements in mapping and cloning NLR genes conferring dominant resistance against potyvirus in the families Fabaceae,Solanaceae,Brassicaceae,and *** compares mechanisms of potyviral protein recognition and downstream signaling employed by NLRs and discusses strategies for exploiting NLRs to better control diseases caused by potyviruses.

关键词： NLR Potyvirus resistance Genetic diversity Mapping Engineer

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Rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)} with fast-responsive photochromism and switchable luminescence properties

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Journal of Rare Earths 2024年第2期42卷 286-292,I0003页

作者： hong Cui Yanli Yang xue Bai xu Han Wensha Zhang Ying Lu Shuxia Liu Key Laboratory of Polyoxometalate and Reticular Material Chemistry of the Ministry of Education College of ChemistryNortheast Normal UniversityChangchun 130024China

Four rare earth inorganic-organic hybrid compounds based on Keggin-type polyoxometalate {SiW_(12)}with general formula [{RE(DMF)_(4)(H_(2)O)_4RE(DMF)_(6)}_(2){SiW_(12)O_(40)}_(3)](RE = La(1),Pr(2),Sm(3),Eu(4),DMF=N,N-dimethylformamide) were synthesized by the conventional solution *** analyses indicate that four compounds are isostructural and are all built from three [SiW_(12)O_(40)]^(4-) polyoxoanions and DMF ligands linked by RE^(3+).Compounds 1-4 are extremely sensitive to UV light and present excellent photochromic properties,in which the coloring and fading time of samples are both no more than 2 min,and the reversible coloring-fading process can be repeated for at least 10 cycles with little fatigue,suggesting that compounds 1-4 can be a series of fast-responsive and durable photochromic ***,the solid-state photoluminescence spectra of compounds 3(Sm) and 4(Eu)display strong characteristic emissions of rare earth ions based on f-f ***,compound4(Eu) has a longer fluorescence lifetime up to 566.74 μ***,co mpounds 3(Sm) and 4(Eu) exhibit the switchable luminescence behavior induced by photochromism,which allows them to be used as potential molecular switches.

关键词： Inorganic-organic hybrid Keggin-type polyoxometalates Rare earths Photochromism Photoluminescence

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Experimental and numerical study of combustion characteristics of ammonia-hydrogen-air swirling flame with/without secondary air injection

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Chinese Journal of Aeronautics 2024年第4期37卷 243-255页

作者： Chunyu LIU Chenhu GAO Yue HUANG Hua jin Dan ZHAO Wenjiang xu Yancheng YOU School of Aerospace Engineering Xiamen UniversityXiamen 361005China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Mechanical Engineering University of CanterburyChristchurch 8041New Zealand

Ammonia (NH_(3)) is currently considered to be a potential carbon-free alternative fuel,and its large-scale use as such would certainly decrease greenhouse gas emissions and meet increasingly stringent emission *** the low flame propagation speed and high NO production of NH_(3) hinder its direct application as a renewable fuel,co-combustion of NH_(3)–H_(2)is an effective way to overcome these *** this study,the combustion characteristics of NH_(3)–H_(2)swirling flames under different equivalence ratios and H_2blending ratios conditions are both numerically and experimentally ***,the One-Dimensional (1D) laminar flame computation presents a comparison base and the Three-Dimensional (3D) numerical simulation yields detailed flame property ***,the high-speed camera takes instantaneous swirl flame images and the gas analyzer measures the NO emission at the exit plane of the flame *** and quantitative analysis is performed on the flame structure and NO emission for a series of NH_(3)–H_(2)swirl *** variation trends of the NO emission calculated using different techniques agree very *** quantitative results show that the NO emissions are much higher at lean equivalence ratios than those at rich equivalence ratios,and such difference is closely related to the combustion flame ***,it is shown that the utilization of secondary air injection can achieve a significant reduction in NO emissions at the exit of the combustion chamber at equivalence ratios less than or equal to 0.9.

关键词： Ammonia combustion Swirling flow NO emission characteristics Secondary combustion Chemical reaction mechanism

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Acaricidal effect of the antimicrobial metabolite xenocoumacin 1 on spider mite control

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Journal of Integrative Agriculture 2024年第3期23卷 948-959页

作者： Jiaxing Wei hong Yan Jie Ren Guangyue Li Bo Zhang xuenong xu Institute of Plant Protection Chinese Academy of Agricultural SciencesBeijing 100193China State Key Laboratory for Biology of Plant Diseases and Insect Pests Beijing 100193China Key Laboratory of Natural Enemies Insects Ministry of Agriculture and Rural AffairsBeijing 100193China

The two-spotted spider mite,Tetranychus urticae Koch,is one of the most harmful pests in many agroecosystems *** effectively manage this pest,there is an urgent need to develop novel bio-active acaricides that support integrated pest management strategies targeting *** this study,we explored the acaricidal effects of xenocoumacin 1 (Xcn1) on *** and its predator Neoseiulus californicus using the highly puri?ed ***1 was extracted and purified from the cell-free supernatant of the Xenorhabdus nematophila CB6 mutant constructed by the easy promoter activated compound identi?cation (easyPACId) *** the concentration of Xcn1 exceeded 100μg mL~(–1),the survival rate of spider mite adults declined to below 40%and the fecundity was decreased by 80%at six days *** concentrations of 25 and 50μg mL~(–1),Xcn1 signi?cantly impeded spider mite development by inhibiting the ***,neither concentration had any adverse effects on the survival or reproduction of the predatory mite *** results from laboratory and semi-?eld experiments consistently demonstrated the effectiveness of the antimicrobial metabolite Xcn1 in controlling pest mites at both the molecular and physiological *** study offers a promising possibility that combines the compatible biocontrol agents of Xcn1 and predatory mites for integrated pest mite control.

关键词： pest management predatory mite Xcn1 morphology developmental inhibition transcriptome

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Micropillar compression using discrete dislocation dynamics and machine learning

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Theoretical & Applied Mechanics Letters 2024年第1期14卷 39-47页

作者： jin Tao Dean Wei Junshi Yu Qianhua Kan Guozheng Kang xu Zhang School of Mechanics and Aerospace Engineering Southwest Jiaotong UniversityChengdu 610031China State Key Laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

Discrete dislocation dynamics(DDD)simulations reveal the evolution of dislocation structures and the interaction of *** study investigated the compression behavior of single-crystal copper micropillars using fewshot machine learning with data provided by DDD *** types of features are considered:external features comprising specimen size and loading orientation and internal features involving dislocation source length,Schmid factor,the orientation of the most easily activated dislocations and their distance from the free *** yielding stress and stress-strain curves of single-crystal copper micropillar are predicted well by incorporating both external and internal features of the sample as separate or combined *** is found that the machine learning accuracy predictions for single-crystal micropillar compression can be improved by incorporating easily activated dislocation features with external ***,the effect of easily activated dislocation on yielding is less important compared to the effects of specimen size and Schmid factor which includes information of orientation but becomes more evident in small-sized ***,incorporating internal features,especially the information of most easily activated dislocations,improves predictive capabilities across diverse sample sizes and orientations.

关键词： Discrete dislocation dynamics simulations Machine learning Size effects Orientation effects Microstructural features

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Effect of exogenous flavins on the microbial corrosion by Geobacter sulfurreducens via iron-to-microbe electron transfer

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Journal of Materials Science & Technology 2024年第4期171卷 129-138页

作者： Yuting jin Jiaqi Li Mingxing Zhang Borui Zheng Dake xu Tingyue Gu Fuhui Wang Shenyang National Laboratory for Materials Science Northeastern UniversityShenyang 110819China Key Laboratory for Anisotropy and Texture of Materials(Ministry of Education) Northeastern UniversityShenyang 110819China Department of Chemical and Biomolecular Engineering Institute for Corrosion and Multiphase TechnologyOhio UniversityAthens OH 45701USA

Microbes can cause or accelerate metal corrosion,leading to huge losses in corrosion damages each *** sulfurreducens is a representative electroactive bacterium in many soils,sediments,and wastew-ater *** has been confirmed to directly extract electrons from elemental ***,little is known about the effect of electron shuttles in *** corrosion on stainless *** this study,we report that exogenous flavins promote iron-to-microbe electron transfer,accelerating micro-bial *** caused 1.3 times deeper pits and increased electron uptake(with 2 times increase of i_(corr))from stainless steel when riboflavin was added to the culture ***-deficient mutant data suggest that *** utilizes riboflavin as a bound-cofactor in outer membrane c-type *** finding that,in the presence of microbes,riboflavin can substantially accelerate corrosion highlights the role of flavin redox cycling for enhanced iron-to-microbe electron transfer by *** and provides new insights in microbial corrosion.

关键词： Extracellular electron transfer Microbiological corrosion Geobacter sulfurreducens Outer membrane c-type cytochromes Exogenous flavins

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Multimode Design and Analysis of an Integrated Leg-Arm Quadruped Robot with Deployable Characteristics

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Chinese Journal of Mechanical Engineering 2024年第3期37卷 41-61页

作者： Fuqun Zhao Yifan Wu Xinhua Yang Xilun Ding Kun xu Sheng Guo Xiaodong jin School of Mechanical Engineering and Automation Beihang UniversityBeijing 100191China School of Mechanical Electronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China

To improve locomotion and operation integration, this paper presents an integrated leg-arm quadruped robot(ILQR) that has a reconfigurable joint. First, the reconfigurable joint is designed and assembled at the end of the legarm chain. When the robot performs a task, reconfigurable configuration and mode switching can be achieved using this joint. In contrast from traditional quadruped robots, this robot can stack in a designated area to optimize the occupied volume in a nonworking state. Kinematics modeling and dynamics modeling are established to evaluate the mechanical properties for multiple modes. All working modes of the robot are classified, which can be defined as deployable mode, locomotion mode and operation mode. Based on the stability margin and mechanical modeling, switching analysis and evaluation between each mode is carried out. Finally, the prototype experimental results verify the function realization and switching stability of multimode and provide a design method to integrate and perform multimode for quadruped robots with deployable characteristics.

关键词： Quadruped robot Multimode design Mode switching Locomotion Operation

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