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Journal of Magnesium and Alloys 2024年第1期12卷 98-109页

作者： Shi Shengnan Wang Hongyu Teng Fei Jiang lei sun Juncai sun Jie Zhang Shunhu Transportation Engineering College Dalian Maritime UniversityDalianLiaoning 106026China State Key laboratory of Rolling and Automation Northeastern UniversityShenyangLiaoning 110819China Shagang School of Iron and Steel Soochow UniversitySuzhouJiangsu 215021China

Magnesium alloy is one of the lightest metal structural *** weight is further reduced through the hollow ***,the hollow structure is easily damaged during *** order to maintain the hollow structure and to transfer the stresses during the high temperature deformation,the sand mandrel is *** this paper,the hollow AZ31 magnesium alloy three-channel joint is studied by hot extrusion *** as one of solid granule medium is used to fill the hollow magnesium *** extrusion temperatures are 230℃ and 300℃,*** process parameters(die angle,temperature,bottom thickness,sidewall thickness,edge-to-middle ratio in bottom,bottom shape)of the hollow magnesium alloy are analyzed based on the results of experiments and the finite element *** results are shown that the formability of the hollow magnesium alloy will be much better when the ratio of sidewall thickness to the bottom thickness is 1:*** when edge-to-middle ratio in bottom is about 1:1.5,a better forming product can be *** best bottom shape in these experiments will be convex based on the forming *** grain will be refined obviously after the *** the microstructures will be shown as *** these lines will be well agreement with the mold in the corner.

关键词： AZ31 magnesium alloy Three-channel joint Sand Experiments and the finite element Die angle

Towards Data-Driving Multi-View Evaluation Framework for Scratch

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Tsinghua Science and Technology 2024年第2期29卷 517-528页

作者： Xiaolin Chai yan sun yan Gao Department of Computer Science Beijing University of Posts and TelecommunicationBeijing 100876China Intellectual Property Institute Shandong Polytechnic CollegeJining 272067China

As one of the most popular visual programming languages,Scratch has a lot of evaluation around *** evaluation can help programmers understand their projects *** the same time,it can also provide a reference for them to browse other projects in the online *** of the existing evaluations on Scratch are carried from three perspectives:Computational Thinking(CT)ability,visual presentation aesthetics,and code *** them,the assessment of CT and code quality is mainly carried out from the program script,while the evaluation of visual aesthetics is analyzed from the perspective of image sequences generated by project *** single-view evaluation focuses on the performance of a program in a certain aspect and is *** this paper,we propose a multi-view evaluation framework to integrate various evaluations using different *** quantitatively analyze the assessment of different views driven by *** with overall evaluations that represent human opinions,we analyze their differences and *** experiments,we determine the weights of different integration policies,the proposed multi-view evaluation method can generate evaluation results similar to human opinions.

关键词： Scratch Computational Thinking(CT) visual aesthetic static analysis integration policy machine learning

Feeding prehistoric coastal community:A study of marine faunal remains at the Jingtoushan site

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Science China Earth Sciences 2024年第5期67卷 1574-1590页

作者： Endong WU Guoping sun ying ZHANG School of Culture History and LanguageAustralian National UniversityCanberra 2600Australia Zhejiang Provincial Institute of Cultural Relics and Archaeology Hangzhou 310012China National Centre for Archaeology Beijing 100013China

This article examines the abundant marine mollusc,and fish remains at the Jingtoushan shell midden(8,300 to7,800 cal a BP)in Zhejiang Province,China,to investigate the fishing economy,community development,the palaeoenvironment,and their interactions among the prehistoric populations in the lower yangtze River Basin and southeastern coastal *** also attempts to explore the prosperity and decline of coastal settlements in China during the Neolithic Age and the potential reasons for their rise and fall,*** on the ecological and biological principles of marine animals,standard zooarchaeological methods and radiocarbon dating analysis are used for sampling,identification,measurement,and *** show that at least 11 mollusc taxa and 14 fish taxa can be identified from the Jingtoushan faunal *** ancient Jingtoushan residents possibly lived in a settlement close to the coast and engaged in inshore and offshore fishing,hunting,and gathering as their primary subsistence strategies,with low-level rice cultivation as a supplementary means of ***,the changes in the coastal environment could be one of the reasons why the Jingtoushan residents abandoned their *** research contributes to Chinese Neolithic archaeology with new evidence of the exploitation of marine resources around 8000 a BP in the eastern coastal areas and the relationship between Neolithic community development and environmental changes.

关键词： Neolithic Age Marine faunal remains Fishing economy Palaeoenvironment Community development

Assessment of the Characteristics of Demersal Fish Communities Using Species-and Trait-Based Approaches in the Coastal Habitats Along Rongcheng Bay,Shandong Peninsula,China

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Journal of Ocean University of China 2024年第3期23卷 786-796页

作者： yUAN Shunjie sun Xin TU Zhong sun Jie WANG Xianning ZHANG Peidong Key laboratory of Mariculture(Ocean University of China) Ministry of EducationQingdao 266003China Shandong Fisheries Development and Resource Conservation Center Yantai 264003China

Biodiversity declines have motivated many studies on the relationship between species diversity and ecosystem *** this study,we described the spatial-temporal characteristics of demersal fish communities along a coastal habitat in Rongcheng Bay,Shandong Peninsula,China with both species-based and biological trait-based *** field survey was carried out monthly using traps from April to October of 2018,and divided into three seasons(spring:April and May;summer:June,July and August;autumn:September,October and November).The study area included five distinct habitats:seagrass bed,natural rocky reef,bare sand,artificial reef together with natural rocky reef,and artificial reef together with bare *** analyzed the fish communities with three taxonomic diversity indices,including Shannon-Wiener,Simpson,and Pielou Evenness,as well as four functional diversity indices,including FRic,FEve,FDiv,and FDis,based on 7 functional groups which are categorized into 27 *** results showed that there were no significant differences in taxonomic diversity indices among different habitats in the three ***,significant differences were found in the functional richness of fish communities among different habitats in three *** bed represented the highest functional richness in spring and *** study demonstrates that seagrass bed is very important in enhancing the functional diversity of fish communities in a complex *** study also indicates that the combination of taxonomic diversity and functional diversity will provide a more detailed description of the characteristics of fish communities.

关键词： complex habitat biological traits biodiversity fish communities

Influence of nitrogen status on fermentation performances of non-Saccharomyces yeasts:a review

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Food Science and Human Wellness 2024年第2期13卷 556-567页

作者： Jinchen li Mengmeng yuan Nan Meng Hehe li Jinyuan sun Baoguo sun Key laboratory of Brewing Molecular Engineering of China light Industry Beijing Key Laboratory of Flavor ChemistryBeijing Technology&Business UniversityBeijing 100048China

Nitrogen,one of the most crucial nutrients present in grapes and musts,plays a key role in yeast activities during alcoholic *** influences are imposed on yeast growth and fermentation performances including the formation of secondary *** cerevisiae,the main yeast responsible for fermentation,has been studied extensively regarding nitrogen *** the other hand,a similar study for non-Saccharomyces yeasts,whose contributions to winemaking have gradually been acknowledged,remains to be fully explored,with a few studies being *** review starts by discussing nitrogen impacts on non-Saccharomyces yeast growth and fermentation kinetics in different case scenarios,then proceeds to summarize the nitrogen preferences of individual yeast strains with regulation mechanisms elucidated by recent *** discussions on the influences on the production of volatile compounds and proposed pathways therein are made,followed by future work suggested as the final *** summarizing the nitrogen impacts on non-Saccharomyces yeasts throughout alcoholic fermentation,this review will be helpful in obtaining a more comprehensive view on these non-conventional wine yeasts in terms of nutrient requirements and corresponding volatile *** gaps will therefore be elucidated for future research.

关键词： Non-Saccharomyces yeasts Nitrogen Fermentation kinetics Nitrogen preference Wine aroma

Heparin-binding protein as a predictor of mortality in patients with diabetes mellitus and community-acquired pneumonia in intensive care unit:a propensity score matched study

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World Journal of Emergency Medicine 2024年第4期15卷 263-272页

作者： yuhan sun Baoqing sun Zhigang Ren Mingshan Xue Changju Zhu Qi liu Translational Medicine Center Department of Emergency Medicinethe First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China State Key laboratory of Respiratory Disease National Clinical Research Center for Respiratory DiseaseGuangzhou Institute of Respiratory Healththe First Affiliated Hospital of Guangzhou Medical UniversityGuangzhou 510230China Department of Infectious Disease the First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China Henan Medical Key laboratory of Emergency and Trauma Research Department of Emergency Medicinethe First Affiliated Hospital of Zhengzhou UniversityZhengzhou 450052China

BACKGROUND:Patients with diabetes mellitus(DM)are vulnerable to community-acquired pneumonia(CAP),which have a high mortality *** aimed to investigate the value of heparin-binding protein(HBP)as a prognostic marker of mortality in patients with DM and ***:This retrospective study included CAP patients who were tested for HBP at intensive care unit(ICU)admission from January 2019 to April *** were allocated to the DM or non-DM group and paired with propensity score *** characteristics and clinical outcomes up to 90 days were *** primary outcome was the 10-day *** operating characteristic(ROC)curves,Kaplan-Meier analysis,and Cox regression were used for statistical ***:Among 152 enrolled patients,60 pairs were successfully *** was no significant difference in 10-day mortality,while more patients in the DM group died within 28 d(P=0.024)and 90 d(P=0.008).In the DM group,HBP levels at ICU admission were higher in 10-day non-survivors than in 10-day survivors(median 182.21[IQR:55.43-300]ng/ml *** 66.40[IQR:34.13-107.85]ng/ml,P=0.019),and HBP levels could predict the 10-day mortality with an area under the ROC curve of *** cut-off value,sensitivity,and specificity were 160.6 ng/ml,66.7%,and 90.2%,*** Cox regression analysis indicated that HBP was an independent prognostic factor for 10-day(HR 7.196,95%CI:1.596-32.455,P=0.01),28-day(HR 4.381,95%CI:1.449-13.245,P=0.009),and 90-day mortality(HR 4.581,95%CI:1.637-12.819,P=0.004)in patients with ***:Plasma HBP at ICU admission was associated with the 10-day,28-day,and 90-day mortality,and might be a prognostic factor in patients with DM and CAP.

关键词： Community-acquired pneumonia Diabetes mellitus Heparin-binding protein Propensity score match

Changes in extreme high temperature warning indicators over China under different global warming levels

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Science China Earth Sciences 2024年第6期67卷 1895-1909页

作者： yuxia ZHANG ying sun Ting HU Chinese Academy of Meteorological Sciences Beijing 100081China National Climate Center Laboratory for Climate StudiesChina Meteorological AdministrationBeijing 100081China

High temperature warning indicators play a pivotal role in meteorological departments,serving as crucial criteria for issuing warnings that guide both social production and daily *** their importance,limited studies have explored the relationship between different global warming levels and changes in high temperature warning *** this study,we analyze data from 2,419 meteorological stations over China and utilize the Coupled Model Intercomparison Project Phase 6(CMIP6)models to examine historical changes in high temperature warning indicators used by the China Meteorological *** evaluate model performance and estimate future changes in these indicators using an annual cycle bias correction *** results indicate that since 1961,the number of high temperature days(TX35d and TX40d)and length of season(TX40d and TX40l)with daily maximum temperature reaching or exceeding 35℃ and 40℃ have increased over *** intensity of high temperatures(TXx)has strengthened and the geographical extent affected by high temperatures has *** 2022,the occurrence of 40℃ high temperatures surges,with Eastern China experiencing a two-day increase in TX40d and an extended seasonal length in TX40l by over five *** CMIP6 models have underestimated the high temperature indictors associated with 35℃ during historical periods,notable difference is not observed between the models and observations for TX40d and TX40l,given their rare ***,future projections,after bias correction,indicate that the increasing trends for 35℃ and 40℃ high temperature days and length of season become more pronounced than the raw projection,suggesting a more severe increase than that anticipated *** global warming intensifies,the high temperature days and length of season are projected to increase non-linearly,while the intensity of high temperatures is expected to increase *** every 1℃ increase in global temperature,the intensity is

关键词： Extreme high temperatures Meteorological warning CMIP6 Global warming levels Future projection

Data-driven Detection and Identification of line Parameters with PMU and Unsynchronized SCADA Measurements in Distribution Grids

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CSEE Journal of Power and Energy Systems 2024年第1期10卷 261-271页

作者： Jinping sun Qifang Chen Mingchao Xia School of Electrical Engineering Beijing Jiaotong University(BJTU)Beijing 100044China

line parameters play an important role in the control and management of distribution ***,phasor measurement unit(PMU)systems and supervisory control and data acquisition(SCADA)systems coexist in distribution ***,SCADA and PMU measurements usually do not match each other,resulting in inaccurate detection and identification of line parameters based on *** solve this problem,a data-driven method is *** measurements are taken as samples and PMU measurements as the population.A probability parameter identification index(PPII)is derived to detect the whole line parameter based on the probability density function(PDF)parameters of the *** parameter identification,a power-loss PDF with the PMU time stamps and a power-loss chronological PDF are derived via kernel density estimation(KDE)and a conditional ***,the power-loss samples with the PMU time stamps and chronological correlations are generated by the two PDFs of the power loss via the Metropolis-Hastings(MH)***,using the power-loss samples and PMU current measurements,the line parameters are identified using the total least squares(TlS)*** simulations demonstrate the effectiveness of the proposed method for distribution network line parameter detection and identification.

关键词： Distribution systems line parameter detection and identification probability density function sampling algorithm the time skew of PMU and SCADA measurements

On the size generalizibility of graph neural networks for learning resource allocation

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Science China(Information Sciences) 2024年第4期67卷 239-254页

作者： Jiajun WU Chengjian sun Chenyang yANG Beihang University School of Electronics and Information Engineering

Size generalization is important for learning resource allocation policies in wireless systems with time-varying scales. If a neural network for learning a wireless policy is not generalizable to the size of its input, it has to be re-trained whenever the system scale changes, which hinders its practical use due to the unaffordable training costs. Graph neural networks(GNNs) have been shown with size generalization ability empirically when optimizing resource allocation. yet, are GNNs naturally size generalizable? In this paper,we argue that GNNs are not always size generalizable for resource allocation. We find that the aggregation and activation functions of the GNNs for learning a class of wireless policies play a key role in their size generalization ability. We take the GNN with the mean aggregator, called mean-GNN, as an example to reveal a size generalization condition. To demonstrate how to satisfy the condition, we learn power and bandwidth allocation policies for ultra-reliable low-latency communications and show that selecting or pretraining the activation function in the output layer of mean-GNN can make the GNN size *** results validate our analysis and evaluate the performance of the learned policies.

关键词： size generalization graph neural networks resource allocation permutation equivariance

Effect of Al_(2)O_(3)on the Mechanical Properties of(B_(4)C+Al_(2)O_(3))/Al Neutron Absorbing Materials

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Acta Metallurgica Sinica(English letters) 2024年第8期37卷 1411-1420页

作者： J.X.Cai B.M.Shi N.li y.liu Z.G.Zhang y.N.Zan Q.Z.Wang B.l.Xiao Z.y.Ma Shi‑Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Key laboratory of Nuclear Materials and Safety Assessment Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China Nuclear Equipment Division Beijing Institute of Nuclear EngineeringChina Nuclear Power Engineering Co.Ltd.Beijing 100840China Department of Materials Science School of Mechanical EngineeringShenyang UniversityShenyang 110044China

B_(4)C/Al composites are widely utilized as neutron absorbing materials for the storage and transportation of spent nuclear *** order to improve the high-temperature mechanical properties of B_(4)C/Al composites,in-situ nano-Al_(2)O_(3)was introduced utilizing oxide on Al powder *** this study,the Al_(2)O_(3)content was adjusted by utilizing spheroid Al powder with varying diameters,thereby investigating the impact of Al_(2)O_(3)content on the tensile properties of(B_(4)C+Al_(2)O_(3))/Al *** was found that the pinning effect of Al_(2)O_(3)on the grain boundaries could hinder the recovery of dislocations and lead to dislocation accumulation at high *** the result,with the increase in Al_(2)O_(3)content and the decrease in grain size,the high-temperature strength of the composites increased *** finest Al powder used in this investigation had a diameter of 1.4μm,whereas the resultant composite exhibited a maximum strength of 251 MPa at room temperature and 133 MPa at 350℃,surpassing that of traditional B_(4)C/Al composites.

关键词： Al matrix composites Neutron absorbing materials (B_(4)C+Al_(2)O_(3))/Al composites High-temperature strength