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Notch Severity Effect on Hydrogen Embrittlement of Type 4340 Steel

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Journal of Materials Science & Technology 1996年第1期12卷 51-56页

作者： Liu, S zhu, zy Ke, W Hardie, D UNIV NEWCASTLE UPON TYNE DEPT MECH MAT & MFG ENGNNEWCASTLE TYNE TE1 7RUTYNE & WEARENGLAND

Hydrogen embrittlement of Type 4340 steel has been investigated by straining round-notched specimens in 10(5) Pa hydrogen atmosphere at a constent cross-head spead of 1.4x10(-4) mm/s. The circumferentially notched specimens exhibited a significant embrittlement when their mechanical behaviour in hydrogen was compared with that in air. Although the effect of notch depth on fracture strength in air is negligible, an increase in the depth of notch increase susceptibility to embrittlement when testing in gaseous hydrogen. However, analysis of the effects is complicated by the facts that (i) the specimens show some degree of notch severity even when strained in air and (ii) the behaviour is complicated by the localised plastic deformation that may occur for relatively shallow notches. Such effects are eliminated at high stress concentration factors, so there is a systematic loss in fracture stress in hydrogen as the notch sensitivity increases from K-t=2.6 to 5.7 (where a 87% reduction of fracture stress occurs) but a relatively stable value is then reached even for very severe notching by fatigue pre-cracking. Whether or not the effect is due to increasing concentration of hydrogen in the triaxial stress region ahead of the notch, there is no doubt that increasing the stress concentration makes hydrogen more effective as an embrittlement agent.

关键词： Carbon steel

Quaternary foraminiferal fossil in the Tianshuihai area of the Qinghai-Xizang Plateau

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Chinese Science Bulletin 1997年第12期42卷 1011-1014页

作者： Li, YF Li, BY Wang, G Li, SJ zhu, zy Institute of Geography Chinese Academy of Sciences Beijing 100101 China

IN July,1995,the authors carried out drilling and sampling at the location 100 m to the south-east of the Tianshuihai Lake(35°21′N,79°35′E,4 840 m a.s.l.) in the northwest of theQinghai-Xizang *** analytical results show that the deposits of lacustrine facies in acorehole and an exposure contain foraminiferal *** late Quaternary foraminiferal fossilwas first found in the Quaternary deposits of lacustrine facies at the hinterland of the Qinghai-

关键词： Qinghai-Xizang Plateau Quaternary foraminiferal fossil.

Label-free biosensing with singular-phaseenhanced lateral position shift based on atomically thin plasmonic nanomaterials

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Light(Science & Applications) 2024年第5期13卷 810-822页

作者： Shaodi zhu Rodolphe Jaffiol Aurelian Crunteanu Cyrille Vézy Sik-To Chan Wu Yuan Ho-Pui Ho Shuwen Zeng Light Nanomaterials&Nanotechnologies(L2n)CNRS-EMR 7004University of Technology of Troyes10000 TroyesFrance. Department of Biomedical Engineering The Chinese University of Hong KongShatinNew TerritoriesHong KongChina XLIM Research Institute UMR 7252 CNRS/University of Limoges123Avenue Albert ThomasLimogesFrance

Rapid plasmonic biosensing has attracted wide attention in early disease diagnosis and molecular biology ***,it was still challenging for conventional angle-interrogating plasmonic sensors to obtain higher sensitivity without secondary amplifying labels such as plasmonic *** address this issue,we developed a plasmonic biosensor based on the enhanced lateral position shift by phase *** singularity presents as a sudden phase retardation at the dark point of reflection from resonating plasmonic substrate,leading to a giant position shift on reflected ***,for the first time,the atomically thin layer of Ge2Sb2Te5(GST)on silver nanofilm was demonstrated as a novel phase-response-enhancing plasmonic *** GST layer was not only precisely engineered to singularize phase change but also served as a protective layer for active silver *** new configuration has achieved a record-breaking largest position shift of 439.3μm measured in calibration experiments with an ultra-high sensitivity of 1.72×10^(8)nm RIU−1(refractive index unit).The detection limit was determined to be 6.97×10^(−7)RIU with a 0.12μm position ***,a large figure of merit(FOM)of 4.54×10^(11)μm(RIU∙°)^(−1)was evaluated for such position shift interrogation,enabling the labelfree detection of trace amounts of *** targeted biosensing experiments,the optimized sensor has successfully detected small cytokine biomarkers(TNF-αand IL-6)with the lowest concentration of 1×10^(−16)*** two molecules are the key proinflammatory cancer markers in clinical diagnosis,which cannot be directly screened by current clinical *** further validate the selectivity of our sensing systems,we also measured the affinity of integrin binding to arginylglycylaspartic acid(RGD)peptide(a key protein interaction in cell adhesion)with different Mn2+ion concentrations,ranging from 1 nM to 1 mM.

关键词： diagnosis protective silver

Fire resistance evaluation through synthetic fire tests and generative adversarial networks

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Frontiers of Structural and Civil Engineering 2024年第4期18卷 587-614页

作者： Aybike Özyüksel Çiftçioğlu M.Z.Naser Department of Civil Engineering Manisa Celal Bayar University45140Türkiye School of Civil&Environmental Engineering and Earth Sciences(SCEEES) Clemson UniversityClemsonSC 29631USA Artificial Intelligence Research Institute for Science and Engineering(AIRISE) Clemson UniversityClemsonSC 29631USA

This paper introduces a machine learning approach to address the challenge of limited data resulting from costly and time-consuming fire experiments by enlarging small fire test data sets and predicting the fire resistance of reinforced concrete *** approach begins by creating deep learning models,namely generative adversarial networks and variational autoencoders,to learn the spatial distribution of real fire *** then use these models to generate synthetic tabular samples that closely resemble realistic fire resistance values for reinforced concrete *** generated data are employed to train state-of-the-art machine learning techniques,including Extreme Gradient Boost,Light Gradient Boosting Machine,Categorical Boosting Algorithm,Support Vector Regression,Random Forest,Decision Tree,Multiple Linear Regression,Polynomial Regression,Support Vector Machine,Kernel Support Vector Machine,Naive Bayes,and K-Nearest Neighbors,which can predict the fire resistance of the columns through regression and *** learning analyses achieved highly accurate predictions of fire resistance values,outperforming traditional models that relied solely on limited experimental *** study highlights the potential for using machine learning and deep learning analyses to revolutionize the field of structural engineering by improving the accuracy and efficiency of fire resistance evaluations while reducing the reliance on costly and time-consuming experiments.

关键词： deep learning fire resistance generative adversarial networks machine learning

Few-shot incremental radar target recognition framework based on scattering-topology properties

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Chinese Journal of Aeronautics 2024年第8期37卷 246-260页

作者： Chenxuan LI Weigang zhu Bakun zhu Yonggang LI Graduate School Space Engineering UniversityBeijing 101400China Department of Electronic and Optical Engineering Space Engineering UniversityBeijing 101400China

The continuous emergence of new targets in open scenarios leads to a substantial decrease in the performance of Inverse Synthetic Aperture Radar(ISAR)recognition ***,data scarcity further exacerbates the challenge of identifying new classes of ISAR *** this paper,a few-shot incremental target recognition framework based on Scattering-Topology Properties(STPIL)is ***,STPIL extracts scattering-topology properties of ISAR targets as recognition ***,the pseudo-incremental training strategy effectively alleviates the algorithm’s forgetting of old knowledge,and improves compatibility with new ***,a feature embedding network,with few parameters,is designed based on the graph neural *** embedding network is highly adaptable to changes in data ***,STPIL fully considers the joint distribution and marginal distribution in scattering features,and uses the Brownian distance metric module to make the scattering-topology features more *** results on both the simulation dataset and the public measured data indicate that STPIL can effectively balance new classes with old classes,and has superior performance to other advanced methods in the incremental recognition of targets.

关键词： Brownian distance metric Graph neural networks Incremental learning Inverse Synthetic Aperture Radar(ISAR) Scattering

Stress-strain relationship for reactive powder concrete with recycled powder under uniaxial compression

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 1015-1027页

作者： Peng zhu Yunming zhu Wenjun QU Liyu XIE College of Civil Engineering Tongji UniversityShanghai 200092China Key Laboratory of Performance Evolution and Control for Engineering Structures of Ministry of Education Tongji UniversityShanghai 200092China

The recycled powder(RP)from construction wastes can be used to partially replace cement in the preparation of reactive powder *** this paper,reactive powder concrete mixtures with RP partially replacing cement,and natural sand instead of quartz,are *** curing is used,instead of steam curing that is normally requested by standard for reactive powder *** influences of RP replacement ratio(0%,10%,20%,30%),silica fume proportion(10%,15%,20%),and steel fiber proportion(0%,1%,2%)are *** effects of RP,silica fume,and steel fiber proportion on compressive strength,elastic modulus,and relative absorption energy are analyzed,and theoretical models for compressive strength,elastic modulus,and relative absorption energy are established.A constitutive model for the uniaxial compressive stress-strain relationship of reactive powder concrete with RP is *** the increase of RP replacement ratio from 0% to 30%,the compressive strength decreases by 42% and elastic modulus decreases by 24%.

关键词： recycled powder reactive powder concrete elastic modulus relative absorbed energy stress-strain relationship

Carbon Emission Effects Driven by Evolution of Chinese Dietary Structure from 1987 to 2020

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Chinese Geographical Science 2024年第1期34卷 181-194页

作者： zhu Yuanyuan ZHANG Yan zhu Xiaohua Key Laboratory of Geographic Process Analysis&Simulation Hubei Province Central China Normal UniversityWuhan430079China Institute of Geographic Sciences and Natural Resources Research Chinese Academy of SciencesBeijing100101China

Exploring carbon emission effects based on the evolution of residents’ dietary structure to achieve the carbon neutrality goal and mitigate climate change is an important *** study took China as the research object(data excluding Hong Kong,Macao and Taiwan) and used the carbon emission coefficient method to quantitatively measure the food carbon emissions from 1987–2020,then analyzed the carbon emission effects under the evolution of dietary *** results showed that during the study period,the Chinese dietary structure gradually changed to a high-carbon consumption *** dietary structure of urban residents developed to a balanced one,while that of rural residents developed to a high-quality *** the study period,the per capita food carbon emissions and total food consumption of Chinese showed an increasing *** per capita food carbon emissions of residents in urban and rural showed an overall upward *** total food carbon emissions in urban increased significantly,while that in rural increased first and then *** influence of beef and mutton on carbon emissions is the highest in dietary *** with the balanced dietary pattern,the food carbon emissions of Chinese residents had not yet reached the peak,but were evolving to a high-carbon consumption pattern.

关键词： dietary structure structural evolution carbon emission effects carbon neutrality China

Designing hierarchical structures for innovative cooling textile

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Nano Research 2024年第10期17卷 9202-9224页

作者： Xiran Du Jinlei Li Bin zhu Jia zhu National Laboratory of Solid State Microstructures College of Engineering and Applied SciencesJiangsu Key Laboratory of Artificial Functional MaterialsNanjing UniversityNanjing 210023China School of Sustainable Energy and Resources Nanjing UniversitySuzhou 215163China

The potential of personal cooling technologies in reducing air conditioning energy consumption and enhancing human thermal comfort is *** review focuses on recent advancements in hierarchical structure design for innovative cooling *** with insights into fundamental heat transfer processes between the human body,textile,and the surroundings,we uncover key control *** the advanced hierarchical structure designs enabling effective radiation,sweat evaporation,conduction management,and integration of cold energy sources for realizing effective human body cooling are systematically ***,we explore multifunctional designs beyond cooling,including switchable cooling-heating and ***,we engage in discussions on unifying cooling performance tests and additional multiple requirements to make strides toward practical *** review is anticipated to be a valuable resource,providing the scientific and industrial communities with a quick grasp of past advancements,current challenges,and future directions in achieving effective human body cooling.

关键词： thermal comfort personal cooling textile hierarchical structures

Old Pinus massoniana forests benefit more from recent rapid warming in humid subtropical areas of central-southern China

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Journal of Forestry Research 2024年第5期35卷 155-170页

作者： Wenxin Li Liangjun zhu Lianhua zhu Mengdan Jing Censhi Qian Yu zhu Paolo Cherubini College of Life Science and Technology Central South University of Forestry and TechnologyChangsha 410004People’s Republic of China Swiss Federal Institute for Forest Snow and Landscape Research WSL8903 BirmensdorfSwitzerland Department of Forest and Conservation Sciences Faculty of ForestryUniversity of British Columbia2004-2424 Main MallVancouverBC V6T 1Z4Canada

Trees progress through various growth stages,each marked by specific responses and adaptation strate-gies to environmental *** the importance of age-related growth responses on overall forest health and management policies,limited knowledge exists regarding age-related effects on dendroclimatic relationships in key subtropical tree *** this study,we employed a den-drochronological method to examine the impact of rapid warming on growth dynamics and climatic sensitivity of young(40–60 years)and old(100–180 years)Pinus mas-soniana forests across six sites in central-southern *** normalized log basal area increment of trees in both age groups increased significantly following rapid warming in *** in young forests further showed a distinct growth decline during a prolonged severe drought(2004–2013),whereas those in old forests maintained growth *** growth was more strongly influenced by temperature than by moisture,particularly in old *** tem-peratures strongly and positively impacted the growth of old trees but had a weaker effect on young *** forests had a significantly lower resistance to extreme drought but faster recovery compared to young ***“divergence problem”was more pronounced in younger forests due to their heightened sensitivity to warming-induced drought and heat *** ongoing warming,young forests also may initially experience a growth decline due to their heightened sensitivity to winter *** findings underscore the importance of considering age-dependent changes in forest/tree growth response to warming in subtropical forest man-agement,particularly in the context of achieving“Carbon Peak&Carbon Neutrality”goals in China.

关键词： Tree rings Pinus massoniana Age effects Drought resilience Subtropical forests Rapid warming