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Micromechanical modeling of longitudinal tensile behavior and failure mechanism of unidirectional carbon fiber/aluminum composites involving fiber strength dispersion

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Chinese Journal of Aeronautics 2024年第9期37卷 312-327页

作者： Qipeng liu Wengang JIANG Yuehua GAO Zhenjun WANG Shanshan shi Zhi SUN Jiangxi Key Laboratory of Forming and Joining Technology for Aerospace Components Nanchang Hangkong UniversityNanchang 330063China School of Locomotive and Rolling Stock Engineering Dalian Jiaotong UniversityDalian 116028China State Key Laboratory of Structural Analysis Optimization and CAE Software for Industrial EquipmentDalian University of TechnologyDalian 116024China

This paper examines the longitudinal tensile behavior and failure mechanism of a new unidirectional carbon fiber reinforced aluminum composite through experiments and simulations.A Weibull distribution model was established to describe the fiber strength dispersion based on single-fiber tensile tests for carbon fibers extracted from the *** constitutive models for the matrix and interface were established based on the uniaxial tensile and single-fiber push-out tests,***,a 3D micromechanical numerical model,innovatively considering the fiber strength dispersion by use of the weakest link and Weibull distribution theories,was estab-lished to simulate the progressive failure behavior of the composite under longitudinal *** to the dispersion of fiber strength,the weakest link of the fiber first fractures,and stress concentra-tion occurs in the surrounding fibers,interfaces,and *** maximum stress concentration fac-tor for neighboring fibers varies nonlinearly with the distance from the fractured *** isolated and clustered fractured fibers are present during the progressive failure process of the *** expansion of fractured fiber clusters intensifies stress concentration and material degradation which in turn enlarges the fractured fiber clusters,and their mutual action leads to the final collapse of the composite.

关键词： Fiber reinforced metals Finite element method 3D micromechanical model Fiber strength dispersion Longitudinal tension Progressive failure

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Nonstationary channel model of reentry plasma sheath for spacecraft: Overview, parameter estimation, and perspective

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Chinese Journal of Aeronautics 2024年第10期37卷 26-49页

作者： Lei shi Zongyuan liu Weimin BAO Bo YAO Yifan WANG Xiaoping LI Yanming liu Fangyan LI School of Aerospace Science and Technology Xidian UniversityXi’an 710126China Key Laboratory of Equipment Efficiency in Extreme Environment Ministry of EducationXi’an 710126China China Aerospace Science and Technology Corporation Beijing 100048China

The Tracking,Telemetering,and Command(TT&C)communication of spacecraft faces severe limitations during *** Electromagnetic(EM)propagation channel is influenced by changes in the flight state and fluid *** addition to the high-speed spatial channel,the Plasma Sheath Channel(PSC),which covers the surface of spacecraft,exhibits unique nonstationary and highly dynamic time-varying *** absence of a channel model for the reentry process of spacecraft negatively impacts the quality evaluation and system design of TT&C *** paper summarizes the methods for nonstationary PSC modeling,involving calculation methods for attenuation and phase shift in the channel,as well as a multistate nonstationary channel statistical model based on a hidden Markov ***,the correlation between amplitude variation and phase variation with electron density is *** paper also provides statistical characteristics of the channel and channel parameters at typical frequencies in the S/C/X/Ka *** findings serve as a reference for the design and evaluation of TT&C communication systems for reentry ***,the paper discusses the prospects of various aspects related to the channel characteristics and modeling of spacecraft PSCs in the shortwave and terahertz/laser bands,as well as the potential challenges in cross-domain spacecraft channel sensing and prediction.

关键词： Spacecraft Plasma sheaths Electromagnetic wave transmission Communication channels Channel estimation

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Investigation on Strengthening Mechanism of China Low-Activation Ferrite Steel upon Thermo-Mechanical Treatment

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Acta Metallurgica Sinica(English Letters) 2024年第2期37卷 373-387页

作者： Dongtian Yang Liangyin Xiong Hongbin Liao Guoping Yang Xiaoyu Wang shi liu Institute of Metal Research Chinese Academy of SciencesShenyang110016China School of Materials Science and Engineering University of Science and Technology of ChinaShenyang110016China Center for Fusion Science Southwestern Institute of PhysicsChengdu610041China

The objective of this study was to investigate the influence of strengthening mechanisms on the high-temperature mechanical properties of China low-activation ferrite(CLF-1)steel,which underwent thermodynamic design and thermo-mechanical treatment(TMT).The microstructure characterization in the normalized and tempered condition and the TMT condition was carried out using optical microscopy,X-ray diffractometer,and scanning electron microscopy with electron backscatter ***-resolution transmission electron microscopy was employed to determine the crystallographic structures of precipitated *** results indicated that the addition of Ti led to an increase in the allocation of C in MC phase and an enhancement in the content of MC *** to CLF-P steel in the normalized and tempered condition,a 1.5-fold increase in dislocation density and an order of magnitude improvement in MX phase density were achieved after *** formation of high-density nano-scale MC phases during TMT played a significant role in precipitation strengthening due to their favorable coherent relationship with the matrix and low interfacial free *** excellent high-temperature mechanical properties observed in CLF-P steel after TMT can be attributed to the combined effects of precipitation strengthening,dislocation strengthening,and lath strengthening.

关键词： China low-activation ferrite(CLF-1)steel Thermo-mechanical treatment MC phase Crystallographic structure Strengthening mechanism

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The unimodal latitudinal pattern of K,Ca and Mg concentration and its potential drivers in forest foliage in eastern China

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Forest Ecosystems 2024年第3期11卷 318-328页

作者： Zhijuan shi Sining liu Yahan Chen Dongdong Ding Wenxuan Han Key Laboratory of Plant-Soil Interactions Ministry of EducationCollege of Resources and Environmental SciencesChina Agricultural UniversityBeijing100193China Forestry Ecological Engineering in the Upper Reaches of the Yangtze River Key Laboratory of Sichuan Province&National Forestry and Grassland Administration Key Laboratory of Forest Resources Conservation and Ecological Safety on the Upper Reaches of the Yangtze River College of ForestrySichuan Agricultural UniversityChengdu611130China Institute of Botany Chinese Academy of SciencesBeijing100093China

Potassium(K),calcium(Ca),and magnesium(Mg)are essential elements with important physiological functions in *** studies showed that leaf K,Ca,and Mg concentrations generally increase with increasing ***,recent meta-analyses suggested the possibility of a unimodal pattern in the concentrations of these elements along latitudinal *** authenticity of this unimodal latitudinal pattern,however,requires validation through large-scale field experimental data,and exploration of the underlying mechanisms if the pattern is ***,we collected leaves of common species of woody plants from 19 montane forests in the north-south transect of eastern China,including 322 species from 160 genera,67 families;and then determined leaf K,Ca,and Mg concentrations to explore their latitudinal patterns and driving *** results support unimodal latitudinal patterns for all three elements in woody plants across eastern China,with peak values at latitude 36.5±1.0°*** shift of plant-functional-type compositions from evergreen broadleaves to deciduous broadleaves and to conifers along this latitudinal span was the key factor contributing to these *** factors,mainly temperature,and to a lesser extent solar radiation and precipitation,were the main environmental *** factors,by altering the composition of plant communities and regulating plant physiological activities,influence the latitudinal patterns of plant nutrient *** findings also suggest that high leaf K,Ca,and Mg concentrations may represent an adaptive strategy for plants to withstand water stress,which might be used to predict plant nutrient responses to climate changes at large scales,and broaden the understanding of biogeochemical cycling of K,Ca,and Mg.

关键词： Potassium Calcium Magnesium Mid-latitudes Latitudinal pattern Plant functional type Water stress Woody plant

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A continuous-wave Nd:YVO_(4.-KGW intracavity Raman laser with over 34. diode-to-Stokes optical efficiency

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High Power Laser Science and Engineering 2024年第2期12卷 62-68页

作者： Quan Sheng Jingni Geng Tianchang liu shijie Fu Wei shi Jianquan Yao Institute of Laser and Optoelectronics School of Precision Instrument and Optoelectronics EngineeringTianjin UniversityTianjinChina Key Laboratory of Optoelectronic Information Technology(Ministry of Education) Tianjin UniversityTianjinChina

We demonstrate a continuous-wave(CW)Nd:YVO_(4.-potassium gadolinium tungstate(KGW)intracavity Raman laser with a diode-to-Stokes optical efficiency of 34.2%.By optimizing the cavity arrangement and reducing the cavity losses,8.4. W Stokes output at 1177 nm was obtained under an incident 878.6 nm diode pump power of 24.8 *** influence of cavity losses on the power and efficiency of the CW Raman laser,as well as the potential for further optimization,was investigated based on the numerical *** observation of thermally-induced output rollover was well explained by the calculation of the thermal lensing and cavity stability,indicating that the end-face curvature played an important role when the end-face of the crystal was highly reflective coated to make the cavity.A 10.9 W Stokes output under 4..9 W incident pump was also demonstrated with a cavity arrangement less sensitive to the end-face curvature,which is the highest output power of CW intracavity Raman lasers reported.

关键词： continuous wave intracavity Raman laser KGW crystal thermal lens

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The risk factors and threshold level of subchronic inhalation exposure of reclaimed water

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Journal of Environmental Sciences 2024年第3期137卷 639-650页

作者： Jiayang Kong Yun Lu Yunru Ren Menghao Chen Gang liu Liangliang shi State Key Joint Laboratory of Environment Simulation and Pollution Control State Environment Protection Key Laboratory of Microorganism Application and Risk ControlSchool of EnvironmentTsinghua UniversityBeijing 100084China

Inhalation of reclaimed water is known to cause lung infammation,and free endotoxins have been shown to be a major risk factor for acute *** exposure has also been shown to induce infammatory responses with visible tissue ***,subchronic risk factors have yet to be identified,and a threshold for the protection of occupational populations during urban reuse is *** this study,potential risk factors in reclaimed water were examined by subchronic exposure with fractionated reclaimed water,and the health risk threshold was tested with a series of diluted reclaimed ***,following a 12-week exposure,macromolecules and microorganisms were found to be two major risk factors in reclaimed water that could cause pulmonary infammation,including increased proportion of polymorphonuclear leukocytes in bronchoalveolar fuid,formation of inducible bronchus-associated lymphoid tissue,and elevation of Immunoglobulin A ***,infammation persisted after a 4.week recovery *** calculated threshold of reclaimed water exposure for mice was 31.8 Endotoxin Unit(EU)/(kg·day)under when exposed to 50%additional relative humidity from reclaimed water at 25℃ for 2 hr/***,the subchronic threshold estimate for humans under the same exposure conditions was found to be 12.2 EU/(kg·day),corresponding to endotoxin levels of 61.7 EU/mL in reclaimed *** threshold level of endotoxin was lower than that in most non-potable reclaimed *** findings of this study suggest that occupational exposure of reclaimed water can serve as a potential risk to workers.

关键词： Reclaimed water Inhalation exposure Risk factor Threshold Infammation Endotoxin

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Quantitative trait loci identification reveals zinc finger protein CONSTANS-LIKE 4.as the key candidate gene of stigma color in watermelon(Citrullus lanatus)

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Journal of Integrative Agriculture 2024年第7期23卷 2292-2305页

作者： Shuang Pei Zexu Wu Ziqiao Ji Zheng liu Zicheng Zhu Feishi Luan shi liu Key Laboratory of Biology and Genetic Improvement of Horticultural Crops(Northeast Region) Ministry of Agriculture and RuralAffairs/College of Horticulture and Landscape ArchitectureNortheast Agricultural UniversityHarbin 150030China Institute of Rural Revitalization Science and Technology Heilongjiang Academy of Agricultural SciencesHarbin 150028China

Stigma color is a critical agronomic trait in watermelon that plays an important role in ***,there are few reports on the regulation of stigma color in *** this study,a genetic analysis of the F2 population derived from ZXG1553(P1,with orange stigma)and W1-17(P2,with yellow stigma)indicated that stigma color is a quantitative trait and the orange stigma is recessive compared with the yellow *** segregant analysis sequencing(BSA-seq)revealed a 3.75 Mb segment on chromosome 6 that is related to stigma ***,a major stable effective QTL Clqsc6.1(QTL stigma color)was detected in two years between cleaved amplified polymorphic sequencing(CAPS)markers Chr06_8338913 and Chr06_934.593 spanning a~1.01 Mb interval that harbors 51 annotated ***97C06G117020(annotated as zinc finger protein CONSTANS-LIKE 4.was identified as the best candidate gene for the stigma color trait through RNA-seq,quantitative real-time PCR(qRT-PCR),and gene structure alignment analysis among the natural watermelon *** expression level of Cla97C06G117020 in the orange stigma accession was lower than in the yellow stigma accessions with a significant difference.A nonsynonymous SNP site of the Cla97C06G117020 coding region that causes amino acid variation was related to the stigma color variation among nine watermelon accessions according to their re-sequencing *** color formation is often related to carotenoids,and we also found that the expression trend of ClCHYB(annotated asβ-carotene hydroxylase)in the carotenoid metabolic pathway was consistent with Cla97C06G117020,and it was expressed in low amounts in the orange stigma *** data indicated that Cla97C06G117020 and ClCHYB may interact to form the stigma *** study provides a theoretical basis for gene fine mapping and mechanisms for the regulation of stigma color in watermelon.

关键词： watermelon stigma color gene mapping zinc finger protein CONSTANS-LIKE 4

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Effect of FeSi additive in dual-chamber sample cup on thermal analysis characteristic values and vermiculating rate of compacted graphite iron

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China Foundry 2024年第1期21卷 91-100页

作者： De-quan shi Ze-yu liu Gui-li Gao Yi-cheng Feng School of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China School of Materials Science and Chemical Engineering Harbin University of Science&TechnologyHarbin 150040China School of Mechanical and Energy Engineering Shanghai Technical Institute of Electronics and InformationShanghai 201411China

Thermal analysis plays a key role in the online inspection of molten iron *** solidification process of molten iron can be reflected by thermal analysis curves,and silicon is one of important elements affecting the solidification of molten *** this study,FeSi75 was added in one chamber of the dual-chamber sample cup,and the influences of FeSi75 additive on the characteristic values of thermal analysis curves and vermiculating rate were *** results show that with the increase of FeSi75,the start temperature of austenite formation TALfirstly decreases and then increases,but the start temperature of eutectic growth TSEF,the lowest eutectic temperature TEU,temperature at maximum eutectic reaction rate TEM,and highest eutectic temperature TERkeep always an *** temperature at final solidification point TEShas little *** FeSi75 additive has different influences on the vermiculating rate of molten iron with different vermiculation,and the vermiculating rate increases for lower vermiculation molten iron while decreases for higher *** to the thermal analysis curves obtained by a dual-chamber sample cup with 0.30wt.%FeSi75 additive in one chamber,the vermiculating rate of molten iron can be evaluated by comparing the characteristic values of these *** time differenceΔtERcorresponding to the highest eutectic temperature TERhas a closer relationship with the vermiculating rate,and a parabolic regression curve between the time differenceΔtERand vermiculating rateηhas been obtained within the range of 65%to 95%,which is suitable for the qualified melt.

关键词： FeSi75 additive characteristic value vermiculating rate thermal analysis compacted graphite iron

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X-ray-activated Bi^(3+)/Pr^(3+)co-doped LiYGeO_4.phosphor with UV and NIR dual-emissive persistent luminescence

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Journal of Rare Earths 2024年第5期42卷 955-961,I0005页

作者： Xianggui Yin Hongyun Zhong Lin liu Junpeng shi Xia Sun Yun Zhang State Key Laboratory of Structural Chemistry Fujian Institute of Research on the Structure of MatterChinese Academy of SciencesFuzhou350002China Xiamen Key Laboratory of Rare Earth Photoelectric Functional Materials Xiamen Institute of Rare Earth MaterialsHaixi InstituteChinese Academy of SciencesXiamen361021China Fujian Science and Technology Innovation Laboratory for Optoelectronic Information of China Fuzhou350108China

X-ray-activated luminescence materials have broad application prospects in photodynamic therapy of deep *** them,X-ray-activated persistent luminescence materials(PLMs)exhibiting multiple emission peaks have drawn extensive attention for the ir capacity to achieve a combination of bioimaging and therapeutic ***,we developed a novel PLM,LiYGeO_4.Bi^(3+),Pr^(3+),that simultaneously exhibits UV and NIR dual persistent luminescence(PersL)emissions after irradiation by *** material can be re peatedly excited by X-ray and emits similar lumine scence intensity every time,which shows good PersL *** addition,LiYGeO_4.Bi^(3+),Pr^(3+)exhibits photostimulated PersL properties by stimulation with a red light-emitting diode(LED)or NIR laser after long-term *** work provides a new choice of X-ray-excited PLMs with UV and NIR dual emission and the novel phosphor shows promise as a potential candidate for the integration of treatment and diagnosis of deep tumors.

关键词： Co-doping X-ray-activated Dual emissions Persistent luminescence Rare earths

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ST-LaneNet: Lane Line Detection Method Based on Swin Transformer and LaneNet

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Chinese Journal of Mechanical Engineering 2024年第1期37卷 130-145页

作者： Yufeng Du Rongyun Zhang Peicheng shi Linfeng Zhao Bin Zhang Yaming liu School of Mechanical Engineering Anhui Polytechnic UniversityWuhu 241000China Automotive New Technology Anhui Engineering and Technology Research Center Anhui Polytechnic UniversityWuhu 241000China School of Automotive and Transportation Engineering Hefei University of TechnologyHefei 230009China

The advancement of autonomous driving heavily relies on the ability to accurate lane lines *** deep learning and computer vision technologies evolve,a variety of deep learning-based methods for lane line detection have been proposed by researchers in the ***,owing to the simple appearance of lane lines and the lack of distinctive features,it is easy for other objects with similar local appearances to interfere with the process of detecting lane *** precision of lane line detection is limited by the unpredictable quantity and diversity of lane *** address the aforementioned challenges,we propose a novel deep learning approach for lane line *** method leverages the Swin Transformer in conjunction with LaneNet(called ST-LaneNet).The experience results showed that the true positive detection rate can reach 97.53%for easy lanes and 96.83%for difficult lanes(such as scenes with severe occlusion and extreme lighting conditions),which can better accomplish the objective of detecting lane *** 1000 detection samples,the average detection accuracy can reach 97.83%,the average inference time per image can reach 17.8 ms,and the average number of frames per second can reach 64.8 *** programming scripts and associated models for this project can be accessed openly at the following GitHub repository:https://***/Duane 711/Lane-line-detec tion-ST-LaneNet.

关键词： Autonomous driving Lane line detection Deep learning Swin transformer

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