检索结果-南通市图书馆

Advances in Atmospheric Sciences 2020年第8期37卷 861-872页

作者： Dongxia LIU Xiushu QIE Yichen CHEN Zhuling SUN Shanfeng yuan Key Laboratory of Middle Atmosphere and Global Environment Observation(LAGEO) Institute of Atmospheric PhysicsChina Academy ScienceBeijing 100029China State Key Laboratory of Severe Weather Chinese Academy of Meteorological SciencesBeijing 100081China Beijing Weather Modification Office Beijing 100089China

Electrical characteristics of an isolated supercell storm observed on 13 June 2014 over Beijing were investigated using lightning data obtained from the Beijing Lightning Network,radar reflectivity,and hydrometeor retrievals during the 6-h *** cloud-to-ground(+CG)lightning took a high percentage of CG *** and during a hail event,+CG lightning was more frequent than negative cloud-to-ground(-CG)lightning,except that+CG lightning took a high percentage at the beginning and in the dissipating *** the hail event ended,-CG lightning dominated and reached its maximum *** analysis of hydrometeors retrieved by X-band polarimetric radar revealed that the discharge concentrated in the convective region with graupel particles and hailstones,whereas graupel,snow and ice crystals in the stratiform *** radiation sources were located mainly in the convective region,some of which were distributed along a gradient of radar reflectivity from the convective region to the stratiform *** indication is that the supercell demonstrated an inverted tripole charge structure before the hail event,which converted to a normal tripole structure after the hail event.

关键词： lightning supercell Beijing Lightning Network charge structure

Experimental investigation of turbulent flows around high-rise structure foundations and implications on scour

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2022年第1期15卷 47-56页

作者： Dong-fang Liang Hao Jia Yang Xiao Sai-yu yuan Department of Engineering University of CambridgeCambridge CB21PZUK State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering Hohai UniversityNanjing 210098China Yangtze Institute for Conservation and Development Hohai UniversityNanjing 210098China

Many studies have been undertaken to predict local scour around offshore high-rise structure foundations(HRSFs),which have been used in constructing the Donghai Wind Farm in ***,there have been few works on the turbulent flow that drives the scour *** this study,the characteristics of the turbulent flow fields around an HRSF were investigated using the particle image velocimetry *** mean flow,vorticity,and turbulence intensity were analyzed in *** relationship between the flow feature and scour development around an HRSF was *** results showed that the flow velocity increased to its maximum value near the third row of the pile *** shear layer and wake vortices could not be fully developed downstream of the last row of the piles at small Reynolds *** strong flow and turbulent fluctuation near the third piles explained the existence of a longtail scour pattern starting from the HRSF shoulders and a trapezoidal deposition region directly downstream of *** laboratory experiment gains insight into the mechanism of the turbulent flow around HRSFs and provides a rare dataset for numerical model verifications.

关键词： High-rise structure foundations(HRSFs) Turbulent flow fields Particle image velocimetry(PIV) Scour Sediment transport

Impact of Polymyxin Resistance on Virulence and Fitness among Clinically Important Gram-Negative Bacteria

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Engineering 2022年第6期8卷 178-185页

作者： yuan Wang Qixia Luo Tingting Xiao Yunying Zhu Yonghong Xiao State Key Laboratory for Diagnosis and Treatment of Infectious Diseases National Clinical Research Center for Infectious DiseasesCollaborative Innovation Center for Diagnosis and Treatment of Infectious DiseasesThe First Affiliated HospitalCollege of MedicineZhejiang UniversityHangzhou 310003China

Humanity is facing an enormous and growing worldwide threat from the emergence of multi-drug-resistant(MDR)Gram-negative bacteria such as Escherichia coli,Klebsiella pneumoniae,and Acinetobacter *** B and E(colistin)constitute the last-line therapies for treating MDR Gram-negative *** is a cationic antibacterial peptide that can destroy the outer membrane of Gram-negative *** the increasing clinical application of polymyxin,however,there have been many reports of the occurrence of polymyxin-resistant Gram-negative *** resistance is mainly mediated by the modification or complete loss of lipopolysaccharide(LPS).LPS is also a virulence factor of Gram-negative bacteria,and alterations of LPS may correlate with *** it is generally believed that the biological costs associated with drug resistance may enable benign susceptible bacteria to overcome resistant bacteria when antibiotic pressure is reduced,some studies have shown that polymyxin-resistant bacteria are associated with higher virulence and greater fitness compared with their susceptible *** predict the development of polymyxin resis-tance and evaluate interventions for its mitigation,it is important to understand the relative biological cost of polymyxin resistance compared with *** impact of polymyxin resistance mecha-nisms on the virulence and fitness of these three Gram-negative bacteria are summarized in this review.

关键词： Polymyxin Resistance Virulence Fitness Gram-negative bacteria Acinetobacter baumannii Escherichia coli Klebsiella pneumoniae

Interaction between microporous magnesia castable and 38CrMoAl steel

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2023年第3期30卷 516-524页

作者： Cheng yuan Yu Liu Guang-qiang Li Yong-shun Zou Ao Huang The State Key Laboratory of Refractories and Metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous Metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Hubei Provincial Key Laboratory for New Processes of Ironmaking and Steelmaking Wuhan University of Science and TechnologyWuhan 430081HubeiChina

The microporous magnesia refractory shows a promising application prospect as tundish lining due to excellent thermal insulation and slag *** effect of interaction between microporous magnesia castable and 38CrMoAl steel containing 0.876 wt.%Al on the cleanliness of 38CrMoAl steel was studied and compared with that of fused magnesia *** results show that the micropores in the microporous magnesia castable can promote the formation of dense and continuous MgO-Al_(2)O_(3)layer,which can inhibit the further pollution of molten steel by refractories,whereas the MgO-Al_(2)O_(3)layer formed in test of fused magnesia castable is not *** 30 min holding,the total oxygen content in the steel samples for the test of microporous magnesia castable is only 42.2%of that for the test of fused magnesia *** inclusions in the steel samples for the test of microporous magnesia castable are also less than those for the test of fused magnesia *** shows that microporous magnesia castable is a promising tundish refractory for the preparation of clean high-Al steel.

关键词： Microporous magnesia castable Fused magnesia castable High-Al steel Cleanliness Tundish lining refractory

Effects of acid drainage from abandoned coal mines on the microbial community of Shandi River sediment,Shanxi Province

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

International Journal of Coal Science & Technology 2021年第4期8卷 756-766页

作者： Di Chen Qiyan Feng Wenbo Li yuan Song Chunhong Zhao Collaborative Innovation Center for Resource Utilization and Ecological Restoration of Old Industrial Base China University of Mining and TechnologyXuzhou 221116China School of Environment Science and Spatial Informatics China University of Mining and TechnologyXuzhou 221116China Institute of Karst Geology of Chinese Academy of Geology Sciences Guilin 541004China

The discharge of acid mine drainage from abandoned high sulfur(S)coal mines has caused serious pollution in the Shandi River,Yangquan,Shanxi *** determine the impact of long-term acid mine drainage on the microorganisms in the river,we collected river sediments from a polluted tributary(Group P)and the mainstream of Shandi River(Group R)to study the bacterial diversity and community *** results showed that the tributary was seriously polluted by acid drainage from abandoned coal mines,with the pH value of the sediment being<2.5,resulting in the low bacterial richness and diversity of the tributary *** Fe-and S-metabolizing bacteria,such as Metallibacterium,Acidiphilium,and Acidithiobacillus,were the dominant genera in Group P samples,while the Group R was dominated by the neutral anaerobic iron-reducing bacteria Geothrix and *** of principal co-ordinates analysis(PCoA)revealed that the bacterial communities are significantly different between groups P and R,and the significant different species were mainly attributed to phylum Proteobacteria,Actinobacteria,and *** distribution of the microbial community is mainly influenced by pH,and the Fe and Cd ***,the dominant genus,is negatively correlated with pH(R^(2)=-0.95)and positively correlated with Fe(R^(2)=0.99),while Geothrix and Geobacter,are mainly affected by the heavy *** study determined the impact of river pollution caused by abandoned coal mine drainage,especially on the microbial diversity and community composition within the river sediment.

关键词： Abandoned coal mine Acid mine drainage Bacterial community River sediment PCoA

Privacy preserving divisible double auction with a hybridized TEE‑blockchain system

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Cybersecurity 2021年第1期4卷 580-593页

作者： Bingyu Liu Shangyu Xie yuanzhou Yang Rujia Wang yuan Hong Illinois Institute of Technology 10 West 35th StreetChicagoIL 60616USA

Double auction mechanisms have been designed to trade a variety of divisible resources(e.g.,electricity,mobile data,and cloud resources)among distributed *** such divisible double auction,all the agents(both buyers and sellers)are expected to submit their bid profiles,and dynamically achieve the best *** practice,these agents may not trust each other without a market ***,smart contract is extensively used to ensure digital agreement among mutually distrustful *** consensus protocol helps the smart contract execution on the blockchain to ensure strong integrity and ***,severe privacy risks would emerge in the divisible double auction since all the agents should disclose their sensitive data such as the bid profiles(i.e.,bid amount and prices in different iterations)to other agents for resource allocation and such data are replicated on all the nodes in the ***,the consensus requirements will bring a huge burden for the blockchain,which impacts the overall *** address these concerns,we propose a hybridized TEE-Blockchain system(system and auction mechanism co-design)to privately execute the divisible double *** designed hybridized system ensures privacy,honesty and high efficiency among distributed *** bid profiles are sealed for optimally allocating divisible resources while ensuring truthfulness with a Nash ***,we conduct experiments and empirical studies to validate the system and auction performance using two real-world applications.

关键词： Privacy Truthfulness Blockchain Smart contract TEE Auction design

Indoor positioning based on tightly coupling of PDR and one single Wi-Fi FTM AP

在线全文

学校读者我要写书评

暂无评论

Geo-Spatial Information Science 2023年第3期26卷 480-495页

作者： yuan Wu Ruizhi Chen Wenju Fu Wei Li Haitao Zhou Guangyi Guo State Key Laboratory of Information Engineering in Surveying Mapping and Remote Sensing(LIESMARS)Wuhan UniversityWuhanChina

The indoor positioning system is now an important technique as part of the Internet-of-Things(IoT)*** indoor positioning techniques,multiple Wi-Fi Access Points(APs)-based positioning systems have been researched a *** is a lack of research focusing on the scene where only one Wi-Fi AP is *** work proposes a hybrid indoor positioning system that takes advantage of the Fine-Timing Measurements(FTM)technique that is part of the IEEE 802.11mc standard,introduced back in *** system uses one single Wi-Fi FTM AP and takes advantage of the built-in inertial sensors of the smartphone to estimate the device’s *** explore both Loosely Coupled(LC)and Tightly Coupled(TC)integration schemes for the sensors’data *** results show that the proposed methods can achieve an average positioning accuracy of about 1 m without knowing the initial *** with the LC integration method,the median error accuracy of the proposed TC fusion algorithm has improved by more than 52%and 67%,respectively,in the two experiments we set up.

关键词： Indoor positioning Wi-Fi Fine Time Measurement(FTM)/Round Trip Time(RTT) Tightly Coupled(TC)integration Pedestrian Dead Reckoning(PDR) Extended Kalman Filter(EKF)

A comparative study on design standards of screw conveyors in China,Germany,and the USA-Part Ⅱ:Discrete element method

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Particuology 2024年第9期92卷 113-125页

作者： yuan Tan Michael Rackl Weijie Yang Johannes Fottner Wenjun Meng Stephan Kessler Technical University of Munich Chair for Materials HandlingMaterial FlowLogisticsGarchingGermany Ibracon–Ingenieurbüro Dr.-Ing.Rackl ZornedingGermany School of Mechanical Engineering Taiyuan University of Science and TechnologyTaiyuanChina

This part of the study aims to evaluate the advantages and disadvantages of technical standards of screw conveyors in China,Germany,and the USA for industrial *** source or determination method of empirical coefficients as well as the theoretical foundation of dimensioning-relevant diagrams in these standards is not explicitly documented in the ***,instead of less efficient on-site tests,the numerical simulation by discrete element method is *** on the geometrical and operational designs determined in three standards for horizontal,slightly inclined,and vertical conveyance of three representative bulk solids(barley,lignite,and sand),the potential influencing factors are *** constant particle and contact parameters,the potential deviations caused by particle models are ***,the accuracy of power consumption calculation of each standard and the divergence between accessible and required mass flows is comprehensively assessed based on the analysis of simulated *** main conclusions are drawn:(1)Particle fall back is barely considered by all three standards and leads to overestimated mass throughput;(2)The decrease in mass throughput caused by an increasing degree of filling can be compensated by slowing down the rotational speed.

关键词： Discrete element method Design standard Screw conveyor Screw auger Bulk solid

Palladium nanoclusters immobilized on defective nanodiamond-graphene core-shell supports for semihydrogenation of phenylacetylene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2019年第6期28卷 31-36页

作者： Fei Huang Zhimin Jia Jiangyong Diao Hua yuan Dangsheng Su Hongyang Liu Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026AnhuiChina College of Chemistry Chongqing Normal UniversityChongqing 401331China

We report a nanocarbon material with nanodiamond(ND) core and graphene shell(ND@G) as a support for Pd nanocatalysts. The designed catalyst performed good selectivity of styrene(85.2%) at full conversion of phenylacetylene and superior stability under mild conditions. Supported Pd catalysts are characterized by means of high resolution transmission electron microscopy(HRTEM), Raman, X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPS) and H2 temperature-programmed reduction(H2-TPR).The results clearly show that formation of the strong metal-support interaction(SMSI) between Pd nanoclusters and the defective graphene shell helpfully modifies the selectivity and stability of the Pd-based catalysts.

关键词： Selective hydrogenation Palladium nano clusters Nanocarbon support Liquid-phase hydrogenation

Wave effects on the anti-liquefaction of the seabed around composite bucket foundation of offshore wind turbines

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2021年第6期33卷 1291-1302页

作者： Li-hua Wang Jin-feng Zhang Run-bo Cai Jing-yuan Li State Key Laboratory of Hydraulic Engineering Simulation and Safety Tianjin University Tianjin 300072China Key Laboratory of Earthquake Engineering Simulation and Seismic Resilience of China Earthquake Administration Tianjin UniversityTianjin 300350China

By using the open-source software OpenFOAM and the grid generation tool the integrated computer engineering and manufacturing code for computational fluid dynamics(ICEM CFD),a computational fluid dynamics-computational structural dynamics(CFD-CSD)coupling model is *** dynamic response and the liquefaction of the seabed around the composite bucket foundation of the offshore wind turbines in the Xiangshui area of Jiangsu Province are *** pore water pressure,the effective stress,the liquefaction depth and the anti-liquefaction effect of the overlying stones are *** is shown that the seabed around the composite bucket foundation will be liquefied under 50 year return waves,the liquefaction width is approximately 1/3 of the wavelength,and the maximum liquefaction depth is approximately 1/4 of the wave *** addition,the overlying stones provide an effective anti-liquefaction ***,less porous overlying stones have a better anti-liquefaction effect.

关键词： Offshore wind turbine composite bucket foundation wave anti-liquefaction overlying stones