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Spatial Distribution Pattern and Influencing Factors of Bed-and-breakfasts(B&Bs)from the Perspective of Urban-rural Differences:A Case Study of Jiaodong Peninsula,China

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Chinese Geographical Science 2024年第4期34卷 752-763页

作者： WANG Xinyue ma Qian management College Ocean University of ChinaQingdao 266100China

There are significant differences between urban and rural bed-and-breakfasts(B&Bs)in terms of customer positioning,economic strength and spatial *** identifying the differences in spatial characteristics and influencing factors of each type,is essential for creating urban and rural B&B agglomeration *** study used density-based spatial clustering of applications with noise(DBSCAN)and the multi-scale geographically weighted regression(MGWR)model to explore similarities and differences in the spatial distribution patterns and influencing factors for urban and rural B&Bs on the Jiaodong Peninsula of China from 2010 to *** results showed that:1)both urban and rural B&Bs in Jiaodong Peninsula went through three stages:a slow start from 2010 to 2015,rapid development from 2015 to 2019,and hindered development from 2019 to ***,urban B&Bs demonstrated a higher development speed and agglomeration intensity,leading to an increasingly evident trend of uneven development between the two sectors.2)The clustering scale of both urban and rural B&Bs continued to expand in terms of quantity and *** B&B clusters characterized by a limited number,but a higher likelihood of transitioning from low-level to high-level *** the number of rural B&B clusters steadily increased over time,their clustering scale was comparatively lower than that of urban B&Bs,and they lacked the presence of high-level clustering.3)In terms of development direction,urban B&B clusters exhibited a relatively stable pattern and evolved into high-level clustering centers within the main urban ***,rural B&Bs exhibited a more pronounced spatial diffusion effect,with clusters showing a trend of multi-center development along the coastline.4)Transport emerged as a common influencing factor for both urban and rural B&Bs,with the density of road network having the strongest explanatory power for their spatial *** terms of differences,populati

关键词： urban-rural bed-and-breakfasts(B&Bs) spatiotemporal evolution density-based spatial clustering of applications with noise(DBSCAN)model multi-scale geographically weighted regression(MGWR) Jiaodong Peninsula China

In silico optimization of actuation performance in dielectric elastomercomposites via integrated finite element modeling and deep learning

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Theoretical & Applied Mechanics Letters 2024年第1期14卷 48-56页

作者： Jiaxuan ma Sheng Sun materials Genome Institute Shanghai UniversityShanghai 200444China Zhejiang Laboratory Hangzhou 311100China Shanghai Frontier Science Center of Mechanoinformatics Shanghai UniversityShanghai 200444China

Dielectric elastomers(DEs)require balanced electric actuation performance and mechanical integrity under applied *** high dielectric particles as fillers provides extensive design space to optimize concentration,morphology,and distribution for improved actuation performance and material *** study presents an integrated framework combining finite element modeling(FEM)and deep learning to optimize the microstructure of DE *** first calculates actuation performance and the effective modulus across varied filler combinations,with these data used to train a convolutional neural network(CNN).Integrating the CNN into a multi-objective genetic algorithm generates designs with enhanced actuation performance and material modulus compared to the conventional optimization approach based on FEM approach within the same *** framework harnesses artificial intelligence to navigate vast design possibilities,enabling optimized microstructures for high-performance DE composites.

关键词： Dielectric elastomer composites Multi-objective optimization Finite element modeling Convolutional neural network

Clinical applications of metagenomics next-generation sequencing in infectious diseases

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2024年第6期25卷 471-484页

作者： Ying LIU Yongjun ma Department of Clinical Laboratory Affiliated Jinhua HospitalZhejiang University School of MedicineJinhua 321000China

Infectious diseases are a great threat to human *** and accurate detection of pathogens is important in the diagnosis and treatment of infectious *** next-generation sequencing(mNGS)is an unbiased and comprehensive approach for detecting all RNA and DNA in a *** the development of sequencing and bioinformatics technologies,mNGS is moving from research to clinical application,which opens a new avenue for pathogen *** studies have revealed good potential for the clinical application of mNGS in infectious diseases,especially in difficult-to-detect,rare,and novel ***,there are several hurdles in the clinical application of mNGS,such as:(1)lack of universal workflow validation and quality assurance;(2)insensitivity to high-host background and low-biomass samples;and(3)lack of standardized instructions for mass data analysis and report ***,a complete understanding of this new technology will help promote the clinical application of mNGS to infectious *** review briefly introduces the history of next-generation sequencing,mainstream sequencing platforms,and mNGS workflow,and discusses the clinical applications of mNGS to infectious diseases and its advantages and disadvantages.

关键词： Metagenomics next-generation sequencing(mNGS) Infectious disease Cerebrospinal fluid(CSF) Oxford Nanopore Technologies(ONT) Microbiome

Two-stage aging treatment to accelerate aging kinetics without impairing strength in B_4C/7A04Al composite

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Science China(Technological Sciences) 2024年第8期67卷 2485-2492页

作者： CHEN YunTao ma GuoNan ZHU ShiZe WANG Dong XIAO BoLv ma ZongYi Shi-Changxu Innovation Center for Advanced materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of materials Science and Engineering University of Science and Technology of ChinaShenyang 110016China Centre of Excellence for Advanced materials Dongguan 523808China

Aging treatments are the key process to obtain satisfactory strength for 7xxxAl alloys and their composites. However, traditional single-stage(SS) aging is time-consuming to reach a peak strength condition. In this study, an efficient 120℃ + 160℃ two-stage(TS) aging treatment was proposed on a B_4C/7A04Al composite fabricated via powder metallurgy(PM) technology, which could acquire similar peak-aging strength but only took about 15% of the time compared to traditional 120℃ SS aging. The evolution of precipitation during the TS aging was investigated, as well as those of the 7A04Al alloys for comparison. In the second stage aging process, the higher aging temperature accelerated the nucleation of η′ phases inside the grains and thus increased the density of precipitates. Moreover, the short aging time limited the coarsening of precipitates and the broadening of precipitatefree zones. The above factors were beneficial for quickly obtaining satisfactory precipitation strengthening effects. The B_4C/7A04Al composite exhibited slower aging kinetics than the 7A04Al alloy in the TS aging. Mg elements consumption by the chemical reaction between B impurities introduced by B_4C particles and the Al matrix was considered to potentially retard the aging kinetics of the B_4C/7A04Al composite. Nevertheless, the precipitation sequence was not affected.

关键词： aluminum matrix composites aging treatment powder metallurgy mechanical properties precipitation

Quantifying Contribution of Recycled Moisture to Precipitation in Temperate Glacier Region,Southeastern Tibetan Plateau,China

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Chinese Geographical Science 2024年第4期34卷 764-776页

作者： ma Yanwei PU Tao SHI Xiaoyi ma Xinggang YU Hongmei College of Geography and Environmental Sciences Zhejiang Normal UniversityJinhua 321004China National Field Science Observation and Research Station of Yulong Snow Mountain Cryosphere and Sustainable Development Northwest Institute of Eco-Environment and ResourcesChinese Academy of SciencesLanzhou 730000China State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-environment and ResourcesChinese Academy of SciencesLanzhou 730000China

Recycled moisture is an important indicator of the renewal capacity of regional water *** to the existence of Yulong Snow Mountain,Lijiang in Yunnan Province,southeast of the Qinghai-Tibet Plateau,China,is the closest ocean glacier area to the equator in *** precipitation samples were collected from 2017 to 2018 in Lijiang to quantify the effect of sub-cloud evaporation and recycled moisture on precipitation combined with the d-excess model during monsoon and non-monsoon *** results indicated that the d-excess values of precipitation fluctuated between–35.6‰and 16.0‰,with an arithmetic mean of 3.5‰.The local meteoric water line(LMWL)wasδD=7.91δ^(18)O+2.50,with a slope slightly lower than the global meteoric water line(GMWL).Subcloud evaporation was higher during the non-monsoon season than during the monsoon *** tended to peak in march and was primarily influenced by the relative *** source of the water vapour affected the proportion of recycled *** to the results of the Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model,the main sources of water vapour in Lijiang area during the monsoon period were the southwest and southeast *** the non-monsoon period,water vapour was transported by a southwesterly *** recycled moisture in Lijiang area between march and October 2017 was 10.62%.Large variations were observed between the monsoon and non-monsoon seasons,with values of 5.48%and 25.65%,*** differences were primarily attributed to variations in the advection of water *** recycled moisture has played a supplementary role in the precipitation of Lijiang area.

关键词： recycled moisture stable isotope precipitation d-excess Hybrid Single-Particle Lagrangian Integrated Trajectory(HYSPLIT)model southeastern Tibetan Plateau China

Land-population-industry based village evolution and its influencing factors in the upper Tuojiang River

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Journal of Mountain Science 2024年第8期21卷 2790-2809页

作者： ZHAN Yunjun JI Yuxin HUANG Jiejun ma Changying ma Chuanqi School of Resources and Environmental Engineering Wuhan University of TechnologyWuhan 430070China

With economic development and urbanization in China,the rural settlements have experienced great *** explore the evolution process of rural settlements in terms of land,population and industry can reveal the development law of rural spatial distribution,population structure and industrial economy in different stages and *** the development status and evolution characteristics of villages in the upper Tuojiang River basin in Southwest China in the past 20 years are of significant *** upper Tuojiang River basin includes the main types of terrain found in the Southwest region:mountainous,plains,and hills,exhibiting a certain typicality of geographical *** study took towns and townships at the town-level scale as the basic unit of research,and constructed an evaluation system for village evolution based on'land,population,and industry'.It employed Criteria Importance Through Inter-Criteria Correlation(CRITIC)analysis to examine the characteristics of village evolution in the area from 2000 to 2020,and used geographic detector analysis to identify the leading factors affecting village *** results show that:(1)From 2000 to 2010,villages in the upper Tuojiang River basin experienced significant changes,and the pace of these transformations slowed from 2010 to 2020.(2)From a comprehensive perspective,from 2000 to 2020,villages in hilly areas show a decline,while villages in plain areas near the city center show a positive urbanization development.(3)Road accessibility and distance from the city center are the main factors that explain the spatial differentiation of village evolution degree in the study *** study elucidates the spatiotemporal evolution characteristics of villages in the upper Tuojiang River basin and identifies the primary factors contributing to their changes,which will provide a reference for investigating the development of rural areas in different terrains of Southwest China.

关键词： Village evolution Land Population Industry Geographic detector

Time-lagged Effects of the Spring Atmospheric Heat Source over the Tibetan Plateau on Summer Precipitation in Northeast China during 1961–2020:Role of Soil Moisture

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Advances in Atmospheric Sciences 2024年第8期41卷 1527-1538页

作者： Yizhe HAN Dabang JIANG Dong SI Yaoming ma Weiqiang ma Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China National Institute of Natural Hazards Ministry of Emergency Management of ChinaBeijing 100085China State Key Laboratory of Tibetan Plateau Earth System Environment and Resources(TPESER)Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China University of Chinese Academy of Sciences Beijing 100049China College of Atmospheric Sciences Lanzhou UniversityLanzhou 730000China National Observation and Research Station for Qomolongma Special Atmospheric Processes and Environmental Changes Dingri 858200China Kathmandu Center of Research and Education Chinese Academy of SciencesBeijing 100101China China-Pakistan Joint Research Center on Earth Sciences Chinese Academy of SciencesIslamabad 45320Pakistan

The spring atmospheric heat source(AHS)over the Tibetan Plateau(TP)has been suggested to affect the Asian summer monsoon and summer precipitation over South ***,its influence on the summer precipitation in Northeast China(NEC)remains *** connection between spring TP AHS and subsequent summer precipitation over NEC from 1961 to 2020 is analyzed in this *** illustrate that stronger spring TP AHS can enhance subsequent summer NEC precipitation,and higher soil moisture in the Yellow River Valley-North China region(YRVNC)acts as a *** spring,the strong TP AHS could strengthen the transportation of water vapor to East China and lead to excessive rainfall in the ***,soil moisture increases,which regulates local thermal conditions by decreasing local surface skin temperature and sensible *** to the memory of soil moisture,the lower spring sensible heat over the YRVNC can last until mid-summer,decrease the land–sea thermal contrast,and weaken the southerly winds over the East Asia–western Pacific region and convective activities over the South China Sea and tropical western *** modulates the East Asia–Pacific teleconnection pattern,which leads to a cyclonic anomaly and excessive summer precipitation over NEC.

关键词： Tibetan Plateau atmospheric heat source Northeast China summer precipitation soil moisture

Effects of gravel on the water absorption characteristics and hydraulic parameters of stony soil

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Journal of Arid Land 2024年第7期16卷 895-909页

作者： ma Yan WANG Youqi ma Chengfeng YUAN Cheng BAI Yiru Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China Ningxia UniversityYinchuan 750021China School of Geography and Planning Ningxia UniversityYinchuan 750021China School of Ecology and Environment Ningxia UniversityYinchuan 750021China

The eastern foothills of the Helan Mountains in China are a typical mountainous region of soil and gravel,where gravel could affect the water movement process in the *** study focused on the effects of different gravel contents on the water absorption characteristics and hydraulic parameters of stony *** stony soil samples were collected from the eastern foothills of the Helan Mountains in April 2023 and used as the experimental materials to conduct a one-dimensional horizontal soil column absorption *** experimental groups with gravel contents of 0%,10%,20%,30%,40%,and 50%were established to determine the saturated hydraulic conductivity(K_(s)),saturated water content(θ_(s)),initial water content(θ_(i)),and retention water content(θ_(r)),and explore the changes in the wetting front depth and cumulative absorption volume during the absorption *** Philip model was used to fit the soil absorption process and determine the soil water absorption *** the length of the characteristic wetting front depth,shape coefficient,empirical parameter,inverse intake suction and soil water suction were derived from the van Genuchten ***,the hydraulic parameters mentioned above were used to fit the soil water characteristic curves,unsaturated hydraulic conductivity(K_(θ))and specific water capacity(C(h)).The results showed that the wetting front depth and cumulative absorption volume of each treatment gradually decreased with increasing gravel *** with control check treatment with gravel content of 0%,soil water absorption rates in the treatments with gravel contents of 10%,20%,30%,40%,and 50%decreased by 11.47%,17.97%,25.24%,29.83%,and 42.45%,*** the gravel content increased,inverse intake suction gradually increased,and shape coefficient,K_(s),θ_(s),andθ_(r)gradually *** the same soil water content,soil water suction and K_(θ)gradually decreased with increasing gravel *** the same soil water s

关键词： stony soil gravel content water absorption characteristics hydraulic parameters one-dimensional horizontal soil column absorption experiment van Genuchten model eastern foothills of Helan Mountains

Effect of Cryogenic Treatment on Microstructure and Tribological Property Evolution of Electron Beam Melted Ti6Al4V

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Journal of Wuhan University of Technology(materials Science) 2024年第4期39卷 1010-1017页

作者：黄西娜 ma Xiaowen XU Tianyi School of Mechanical and Electrical Engineering China University of Mining and Technology-BeijingBeijing 100083China School of Engineering and Technology China University of GeosciencesBeijing 100083China

Cryogenic treatment was used to improve the tribological properties of Ti6Al4V artificial hip joint *** treatment at-196℃with different holding time were carried out on Ti6Al4V specimens fabricated using electron beam melting(EBM),and their microstructure and tribological properties evolution were systematically analyzed by scanning electron microscopy(SEM),vickers hardness,and wear *** experimental results show that the as-fabricated specimen consists of lamellarαphase andβcolumnar ***,the thickness of lamellarαphase decreased after cryogenic *** addition,it can be found that the fineαphase was precipitated and dispersed between the lamellarαphase with the holding time *** hardness shows a trend of first increasing and then *** wear rate of the specimen cryogenic treated for 24 h is the minimum and the average friction coefficient is 0.50,which is reduced by 14.61%compared with the *** wear mechanism of the as-fabricated specimen is severe exfoliation,adhesive,abrasive,and slight fatigue ***,the specimen cryogenic treated for 24 h shows slight adhesive and abrasive *** can be concluded that it is feasibility of utilizing cryogenic treatment to reduce the wear of EBMed Ti6Al4V.

关键词： electron beam melting(EBM) cryogenic treatment microstructure vickers hardness tribological property