检索结果-南通市图书馆

Swimming velocity of spherical squirmers in a square tube at finite fluid inertia

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(english edition) 2024年第9期45卷 1481-1498页

作者： Tongxiao jiang Deming NIe Jianzhong LIN Institute of Fluid Mechanics China Jiliang UniversityHangzhou 310008China Key Laboratory of Impact and Safety engineering(Ningbo University) Ministry of EducationNingbo 315211China Institute of Fluid engineering Zhejiang UniversityHangzhou 310027China

The three-dimensional lattice Boltzmann method(LBM)is used to simulate the motion of a spherical squirmer in a square tube,and the steady motion velocity of a squirmer with different Reynolds numbers(Re,ranging from 0.1 to 2)and swimming types is investigated and analyzed to better understand the swimming characteristics of microorganisms in different ***,as the Reynolds number increases,the effect of the inertial forces becomes significant,disrupting the squirmer's ability to maintain its theoretical ***,as the Reynolds number increases,the structure of the flow field around the squirmer changes,affecting its velocity of ***,the swimming velocity of the squirmer exhibits a quadratic relationship with the type of swimming and the Reynolds ***,the narrow tube exerts a significant inhibitory effect on the squirmer *** addition,although chirality does not directly affect the swimming velocity of the squirmer,it can indirectly affect the velocity by changing its motion mode.

关键词： spherical squirmer swimming characteristics swimming velocity fow structure

Assessments of Data-Driven Deep Learning Models on One-Month Predictions of Pan-Arctic Sea Ice Thickness

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2024年第7期41卷 1379-1390页

作者： Chentao SONG jiang ZHU Xichen LI Institute of Atmospheric Physics Chinese Academy of SciencesBeijing 100029China University of Chinese Academy of Sciences Beijing 100049China

In recent years,deep learning methods have gradually been applied to prediction tasks related to Arctic sea ice concentration,but relatively little research has been conducted for larger spatial and temporal scales,mainly due to the limited time coverage of observations and reanalysis ***,deep learning predictions of sea ice thickness(SIT)have yet to receive ample *** this study,two data-driven deep learning(DL)models are built based on the ConvLSTM and fully convolutional U-net(FC-Unet)algorithms and trained using CMIP6 historical simulations for transfer learning and fine-tuned using reanalysis/*** models enable monthly predictions of Arctic SIT without considering the complex physical processes *** comprehensive assessments of prediction skills by season and region,the results suggest that using a broader set of CMIP6 data for transfer learning,as well as incorporating multiple climate variables as predictors,contribute to better prediction results,although both DL models can effectively predict the spatiotemporal features of SIT *** the predicted SIT anomalies of the FC-Unet model,the spatial correlations with reanalysis reach an average level of 89%over all months,while the temporal anomaly correlation coefficients are close to unity in most *** models also demonstrate robust performances in predicting SIT and SIe during extreme *** effectiveness and reliability of the proposed deep transfer learning models in predicting Arctic SIT can facilitate more accurate pan-Arctic predictions,aiding climate change research and real-time business applications.

关键词： Arctic sea ice thickness deep learning spatiotemporal sequence prediction transfer learning

A Nonparametric Model Checking Test for Functional Linear Composite Quantile Regression Models

在线全文

学校读者我要写书评

暂无评论

Journal of Systems Science & Complexity 2024年第4期37卷 1714-1737页

作者： XIA Lili DU jiang ZHANG Zhongzhan Faculty of Science Beijing University of TechnologyBeijing 100124China

This paper is focused on the goodness-of-fit test of the functional linear composite quantile regression model.A nonparametric test is proposed by using the orthogonality of the residual and its conditional expectation under the null *** proposed test statistic has an asymptotic standard normal distribution under the null hypothesis,and tends to infinity in probability under the alternative hypothesis,which implies the consistency of the ***,it is proved that the test statistic converges to a normal distribution with nonzero mean under a local alternative *** simulations are reported,and the results show that the proposed test has proper sizes and is sensitive to the considered model *** proposed methods are also applied to two real datasets.

关键词： Composite quantile regression consistent test functional data nonparametric test quadratic form

Optimal AP Deployment in Cell-Free Massive MIMO Systems with LoS/NLoS Transmissions:A Stochastic Geometry Approach

在线全文

学校读者我要写书评

暂无评论

China Communications 2024年第9期21卷 146-158页

作者： jiang Ling Zhang Qi Zhu Hongbo jiangsu Key Laboratory of Wireless Communications Nanjing University of Posts and TelecommunicationsNanjing 210003China

Cell-free massive multiple-input multipleoutput(MIMO)is a promising technology for future wireless communications,where a large number of distributed access points(APs)simultaneously serve all users over the same time-frequency *** users and APs may locate close to each other,the line-of-sight(Lo S)transmission occurs more frequently in cell-free massive MIMO ***,in this paper,we investigate the cell-free massive MIMO system with Lo S and non-line-of-sight(NLo S)transmissions,where APs and users are both distributed according to Poisson point *** tools from stochastic geometry,we derive a tight lower bound for the user downlink achievable rate and we further obtain the energy efficiency(ee)by considering the power consumption on downlink payload transmissions and circuitry *** on the analysis,the optimal AP density and AP antenna number that maximize the ee are *** is found that compared with the previous work that only considers NLo S transmissions,the actual optimal AP density should be much smaller,and the maximized ee is actually much higher.

关键词： cell-free massive MIMO energy efficiency LoS/NLoS transmissions stochastic geometry

estimation and verification of green tide biomass based on UAV remote sensing

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2024年第4期42卷 1216-1226页

作者： Xiaopeng jiang Zhiqiang GAO Zhicheng WANG CAS Key Laboratory of Coastal environmental Processes and ecological Remediation Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China Shandong Key Laboratory of Coastal environmental Processes Yantai Institute of Coastal Zone ResearchChinese Academy of SciencesYantai 264003China University of Chinese Academy of Sciences Beijing 100049China

Since 2007,the yellow Sea green tide has broken out every summer,causing great harm to the environment and *** satellite remote sensing(RS)has been used in biomass research,there are several shortcomings,such as mixed pixels,atmospheric interference,and difficult field *** biomass of green tide has been lacking a high-precision estimation *** this study,high-resolution unmanned aerial vehicle(UAV)RS was used to quantitatively map the biomass of green *** utilizing experimental data from previous studies,a robust relationship was established to link biomass to the red-green-blue floating algae index(RGB-FAI).Then,the lab-based model for green tide biomass from visible images taken by the UAV camera was developed and validated by field *** sults show that the accurate and cost-effective method is able to estimate the green tide biomass and its changes in given local waters of the near and far *** study provided an effective complement to the traditional satellite RS,as well as high-precision quantitative techniques for decision-making in disaster management.

关键词： green tide biomass estimation quantitative technique yellow Sea unmanned aerial vehicle(UAV) remote sensing(RS)

Defect engineering and Carbon Supporting to Achieve Ni‑Doped CoP_(3) with High Catalytic Activities for Overall Water Splitting

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第11期16卷 569-584页

作者： Daowei Zha Ruoxing Wang Shijun Tian Zhong‑Jie jiang Zejun Xu Chu Qin Xiaoning Tian Zhongqing jiang Department of Physics Zhejiang Sci-Tech UniversityHangzhou 310018People’s Republic of China Department of Materials and Chemical engineering Ningbo University of TechnologyNingbo 315211People’s Republic of China Guangzhou Key Laboratory for Surface Chemistry of energy Materials Guangdong Engineering and Technology Research Center for Surface Chemistry of Energy MaterialsCollege of Environment and EnergySouth China University of TechnologyGuangzhou 510006People’s Republic of China

This work reports the use of defect engineering and carbon supporting to achieve metal-doped phosphides with high activities and stabilities for the hydrogen evolution reaction(HeR)and the oxygen evolution reaction(OeR)in alkaline ***,the nitrogen-doped carbon nanofiber-supported Ni-doped CoP_(3) with rich P defects(Pv·)on the carbon cloth(p-NiCoP/NCFs@CC)is synthesized through a plasma-assisted phosphorization *** p-NiCoP/NCFs@CC is an efficient and stable catalyst for the HeR and the *** only needs overpotentials of 107 and 306 mV to drive 100 mA cm^(-2) for the HeR and the OeR,*** catalytic activities are higher than those of other catalysts reported *** high activities of the p-NiCoP/NCFs@CC mainly arise from its peculiar structural *** density functional theory calculation indicates that the Pv·richness,the Ni doping,and the carbon supporting can optimize the adsorption of the H atoms at the catalyst surface and promote the strong electronic couplings between the carbon nanofiber-supported p-NiCoP with the surface oxide layer formed during the OeR *** gives the p-NiCoP/NCFs@CC with the high activities for the HeR and the *** used in alkaline water electrolyzers,the p-NiCoP/NCFs@CC shows the superior activity and excellent stability for overall water splitting.

关键词： Plasma electrocatalysis Hydrogen evolution reaction Oxygen evolution reaction Water splitting

Spatio-temporal evaluation of Multi-scale Cultivated Land System Resilience in Black Soil Region from 2000 to 2019:A Case Study of Liaoning Province,Northeast China

在线全文

学校读者我要写书评

暂无评论

Chinese Geographical Science 2024年第1期34卷 168-180页

作者： WANG y.e.jiang yuting ZHU Guoxu School of Management Shenyang Normal UniversityShenyang110034China Northeast Institute of Geography and Agroecology Chinese Academy of SciencesChangchun130012China

It is of great significance to systematically analyze the cultivated land system resilience(CLSR) for the black soil protection and national food *** CLSR is impacted by planting structure adjustment and cultivated land quality decline,posing major hidden dangers to food *** is urgent to evaluate the CLSR at multiple spatio-temporal *** study took Liaoning Province in the black soil region of Northeast China as an *** on the resilience theory,this study constructed the CLSR evaluation system from the input-feedback perspective at the provincial-scale and the city-scale,and used the rank-sum ratio comprehensive evaluation method(RSR) to analyze the key influencing factors of CLSR in Liaoning Province and its 14 cities from 2000 to *** results showed that:1) the time series changes of CLSR at the provincial-scale and the city-scale in Liaoning Province were similar,both showing an increasing trend.2) The CLSR in Liaoning Province presented a spatial pattern of ‘high in the west and low in the east’ at the city-scale.3) There were seven and six main influencing factors of CLSR at the provincial-scale and the city-scale,*** addition to the net income per capita of rural households,other influencing factors of CLSR were different at the provincial-scale and the *** feedback factors were dominant at the provincial-scale,and the input factors and feedback factors were dominant at the *** results could provide a reference for the utilization of black soil and draw on the experience of regional agricultural planning and adjustment.

关键词： cultivated land system resilience(CLSR) rank-sum ratio comprehensive evaluation(RSR) multi-scales influencing factors black soil region Liaoning Province,China

Spatio-temporal variability of surface chlorophyll a in the yellow Sea and the east China Sea based on reconstructions of satellite data of 2001-2020

在线全文

学校读者我要写书评

暂无评论

Journal of Oceanology and Limnology 2024年第2期42卷 390-407页

作者： Weichen XIe Tao WANG Wensheng jiang Key Laboratory of Marine environment and ecology Ocean University of ChinaQingdao 266100China College of Oceanic and Atmospheric Sciences Ocean University of ChinaQingdao 266100China

Chlorophyll-a(Chl-a)concentration is a primary indicator for marine environmental *** spatio-temporal variations of sea surface Chl-a concentration in the yellow Sea(yS)and the east China Sea(eCS)in 2001-2020 were investigated by reconstructing the MODIS Level 3 products with the data interpolation empirical orthogonal function(DINeOF)*** reconstructed results by interpolating the combined MODIS daily+8-day datasets were found better than those merely by interpolating daily or 8-day ***-a concentration in the yS and the eCS reached its maximum in spring,with blooms occurring,decreased in summer and autumn,and increased in late autumn and early *** performing empirical orthogonal function(eOF)decomposition of the reconstructed data fields and correlation analysis with several potential environmental factors,we found that the sea surface temperature(SST)plays a significant role in the seasonal variation of Chl a,especially during spring and *** increase of SST in spring and the upper-layer nutrients mixed up during the last winter might favor the occurrence of spring *** high sea surface temperature(SST)throughout the summer would strengthen the vertical stratification and prevent nutrients supply from deep water,resulting in low surface Chl-a *** sea surface Chl-a concentration in the yS was found decreased significantly from 2012 to 2020,which was possibly related to the Pacific Decadal Oscillation(PDO).

关键词： chlorophyll a(Chl a) data interpolation empirical orthogonal function(DINeOF) empirical orthogonal function(eOF)analysis yellow Sea east China Sea

Oxidative Dehydrogenation of Propane over Supported Nickel Single-Atom Catalyst

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemistry 2024年第4期42卷 370-376页

作者： Qian Zhang Xunzhu jiang yangyang Li yuanlong Tan Qike jiang Xiaoyan Liu Botao Qiao CAS Key Laboratory of Science and Technology on Applied Catalysis Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning116023 China University of Chinese Academy of Sciences Beijing100049 China Dalian National Laboratory for Clean energy Dalian Institute of Chemical PhysicsChinese Academy of SciencesDalianLiaoning116023 China

Oxidative dehydrogenation of propane has been an ever-growing field for propylene production due to its exothermic properties,of which overoxidation is the major drawback,with CO and even CO_(2) as undesired *** the purpose of getting higher propylene selectivity as well as yield,herein,we report Ni single atoms supported on calcium aluminate as an efficient catalyst candidate for propane oxidative *** from higher valence states of Ni1 species,it shows 2—3 times as much propylene selectivity as that of Ni *** 14.2%C_(3)H_(6) yield with 47.3%propylene selectivity has been achieved on Ni single atom catalyst and a good stability during 20 h test can be obtained as well.

关键词： Oxidative dehydrogenation/Nickel Single-atom catalysts Propane Propylene selectivity