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Chinese Journal of Aeronautics 2024年第10期37卷 83-102页

作者： Ruoye XIAO Dong sun Jian YU School of Aeronautic Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Aerodynamics Mianyang 621000China

Shock wave/boundary layer interaction in a 24°turning angle of the compression ramp at Mach number 2.9 controlled by steady microjet is investigated using direct numerical *** different jet spacings which are termed as sparse,moderate and dense are considered,and the induced vortex system and shock structures are compared.A moderate jet spacing configuration is found to generate counter-rotating vortex pairs that transport high-momentum fluid towards the vicinity of wall and strengthen the boundary layer to resist separation,reducing the separation *** dense jet spacing configuration creates a larger momentum deficit region,reducing the friction downstream of the *** of pressure and pressure gradient reveals that dense jet spacing configuration reduces the intensity of separation *** impact of varying jet spacings on the turbulent kinetic energy transport mechanism is also investigated by decomposing the budget terms in the transport ***,the spectral characteristics of the separation region are studied using power spectral density and dynamic mode decomposition methods,revealing that moderate jet spacing configuration suppresses low-frequency fluctuations in the separation region.

关键词： Shock wave/boundary layer interaction Compression ramp Steady microjet Different jet spacings Direct numerical simulation

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

Numerical study on the use of soft material walls to enhance seismic performance of an existing tunnel

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Underground Space 2024年第2期15卷 90-112页

作者： Qiangqiang sun Menghao Hou Daniel Dias Institute of Geotechnical Engineering College of Civil Engineering and ArchitectureHebei UniversityBaoding 071002China Laboratory 3SR CNRS UMR 5521Grenoble Alpes UniversityGrenoble 38000France

Seismic risk is one of the biggest challenges for tunnel safety,and several mitigation techniques have been proposed to enhance the seismic performance of existing *** paper aims to investigate the effectiveness of an innovative approach for reducing the seismic risk of existing tunnels by using soft material walls(SMW)symmetrically installed in the surrounding *** investigation is performed with a two-dimensional numerical model and the effectiveness of SMW in mitigating the seismic-induced lining forces is quantitatively evaluated by reduction *** influences of nonlinear properties of soil,SMW and tunnel lining on the isolation effectiveness are also *** parametric studies show that the computed reduction ratio is strongly affected by the modulus ratio between the SMW and the soil,the wall geometric parameter,and the flexibility *** is more effective for the thick and soft isolation walls that are inserted near a stiff tunnel in the soft *** tunnel seismic response can be reduced by up to 50%for the scenarios ***,the parametric study identifies an optimum normalized depth of SMW and recommends a relation between the maximum isolation effect and the flexibility ***,simple charts are suggested in this work for estimating the isolation effect in specific conditions of the soil and the *** these lines,the results of this work may be used in the seismic retrofitting of an existing tunnel,aiding the preliminary design of the isolation walls.

关键词： Tunnels Earthquakes Seismic analysis Isolation walls Soft material

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

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

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

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

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

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

Solving the Olbers’s Paradox, Explaining the “Red-Shift”, and Challenging the Relativities by “sun Matters Theory” and “sun Model of Universe”, an Evolution of the Einstein’s Static Universe Model

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Natural Science 2024年第2期16卷 7-18页

作者： Wanpeng sun Independent Researcher Newfoundland Canada

Olbers’s paradox, known as the dark night paradox, is an argument in astrophysics that the darkness of the night sky conflicts with the assumption of an infinite and eternal static universe. Big-Bang theory was used to partially explain this paradox, while introducing new problems. Hereby, we propose a better theory, named sun Matters Theory, to explain this paradox. Moreover, this unique theory supports and extended the Einstein’s static universe model proposed by Albert Einstein in 1917. Further, we proposed our new universe model, “sun Model of Universe”. Based on the new model and novel theory, we generated innovative field equation by upgrading Einstein’s Field Equation through adding back the cosmological constant, introducing a new variable and modifying the gravitationally-related concepts. According to the sun Model of Universe, the dark matter and dark energy comprise the so-called “sun Matters”. The observed phenomenon like the red shift is explained as due to the interaction of ordinary light with sun Matters leading to its energy and frequency decrease. In sun Model, our big universe consists of many universes with ordinary matter at the core mixed and surrounded with the sun Matters. In those universes, the laws of physics may be completely or partially different from that of our ordinary universe with parallel civilizations. The darkness of night can be easily explained as resulting from the interaction of light with the sun Matters leading to the sharp decrease in the light intensity. sun Matters also scatter the light from a star, which makes it shining as observed by Hubble. Further, there is a kind of sun Matters named “sun Waters”, surrounding every starts. When lights pass by the sun, the sun Waters deflect the lights to bend the light path. According to the sun Model, it is the light bent not the space bent that was proposed in the theory of relativities.

关键词： Olbers’s Paradox sun Matters Theory sun Model of Universe Einstein’s Universe Dark Mass