检索结果-南通市图书馆

Tribological behavior of lubricant-impregnated porous polyimide

维普期刊数据库

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

Friction 2024年第4期12卷 711-725页

作者： Jinbang LI Ningning ZHOU janet S.S.WONG School of Mechanical Engineering and Mechanics Ningbo UniversityNingbo 315211China Beijing Key Laboratory of Long-life Technology of Precise Rotation and Transmission Mechanisms Beijing Institute of Control EngineeringBeijing 100029China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK

Porous materials impregnated with lubricants can be used in conditions where limited lubricant is *** this work,three porous polyimides(PPI)with different densities were ***(PAO)impregnated PPI(iPPI)discs were rubbed against steel and sapphire *** operando observations of the iPPI-sapphire contacts show that oil is released under an applied load,forming a meniscus around *** at the outlet is created at high sliding *** amount of released oil increases with increasing PPI *** moduli,E*,estimated based on the actual contact size show that trapped oil in iPPIs contributes to load *** higher speeds,tribological rehydration of the contact occurs in low density iPPI,with that E*rises with *** high density PPIs,high speeds give a constantly high E*which is limited by the viscoelastic properties of the PPI network and possibly the rate of oil *** of iPPI-steel contacts is governed by the mechanical properties of the PPI,the flow of the lubricant,and the roughness of the PPI *** low-and medium-density(highly porous,high roughness)PPIs,large amount of oil is released,and lubrication is mainly via lubricant restricted in the contact in the pores and possibly tribological *** high density(low porosity)PPI,with lower roughness,hydrodynamic lubrication is achieved which gives the lowest *** results show that polymeric porous materials for effective lubrication require the optimization of its surface roughness,stiffness,oil flow,and oil retentions.

关键词： polyimide porous material friction mechanism polymer limited lubrication

A compartment and metapopulation model of Rocky Mountain spotted fever in southwestern United States and northern Mexico

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Infectious Disease Modelling 2024年第3期9卷 713-727页

作者： Laura Backus Patrick Foley janet Foley School of Veterinary Medicine Department of Medicine and EpidemiologyUniversity of CaliforniaDavisCAUSA Department of Biological Sciences California State UniversitySacramentoCAUSA

Rocky Mountain spotted fever(RMSF)is a fatal tick-borne zoonotic disease that has emerged as an epidemic in western North America since the turn of the 21st *** the US south-western border and across northern Mexico,the brown dog tick,Rhipicephalus sanguineus,is responsible for spreading the disease between dogs and *** widespread nature of the disease and the ongoing epidemics contrast with historically sporadic patterns of the *** dogs are amplifying hosts for the Rickettsia rickettsii bacteria,transmission dynamics between dogs and ticks are critical for understanding the *** this paper,we developed a compartment metapopulation model and used it to explore the dynamics and drivers of RMSF in dogs and brown dog ticks in a theoretical region in western North *** discovered that there is an extended lag—as much as two years—between introduction of the pathogen to a naïve population and epidemic-level transmission,suggesting that infected ticks could disseminate extensively before disease is detected.A single large city-size population of dogs was sufficient to maintain the disease over a decade and serve as a source for disease in surrounding smaller *** model is a novel tool that can be used to identify high risk areas and key intervention points for epidemic RMSF spread by brown dog ticks.

关键词： Compartment model Rocky mountain spotted fever SIR model Metapopulation Zoonosis

A Vertex Network Model of Arabidopsis Leaf Growth

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications on Applied Mathematics and Computation 2024年第1期6卷 454-488页

作者： Luke Andrejek janet Best Ching-Shan Chou Aman Husbands Department of Mathematics The Ohio State UniversityColumbusOHUSA Department of Biology The University of PennsylvaniaPhiladelphiaPAUSA

Biology provides many examples of complex systems whose properties allow organisms to develop in a highly reproducible,or robust,*** such system is the growth and development of flat leaves in Arabidopsis *** mechanistically challenging process results from multiple inputs including gene interactions,cellular geometry,growth rates,and coordinated cell *** better understand how this complex genetic and cellular information controls leaf growth,we developed a mathematical model of flat leaf *** two-dimensional model describes the gene interactions in a vertex network of cells which grow and divide according to physical forces and genetic ***,the model predicts the presence of an unknown additional factor required for the formation of biologically realistic gene expression domains and iterative cell *** two-dimensional model will form the basis for future studies into robustness of adaxial-abaxial patterning.

关键词： Robustness Adaxial-abaxial patterning Mathematical modeling Gene regulatory networks(GRNs) Transcription factors Small RNAs

Tribological evaluation of thermoplastic polyurethane-based bearing materials under water lubrication:Effect of load,sliding speed,and temperature

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Friction 2024年第8期12卷 1801-1815页

作者： Shaoli JIANG janet SSWONG Debashis PUHAN Tian YUAN Xiuqin BAI Chengqing YUAN State Key Laboratory of Maritime Technology and Safety Wuhan University of TechnologyWuhan 430063China Department of Mechanical Engineering Imperial College LondonLondon SW72AZUK Yusuf Hamied Department of Chemistry University of CambridgeLensfield RoadCambridge CB21EWUK

Polymers are widely used in bearing *** the case of water-lubricated stern tube bearings,thermoplastic polyurethane(TPU)-based composites are used due to their excellent wear resistance,corrosion resistance,and tunable mechanical *** tribological performance,however,depends on operating *** this work,TPU was blended with carbon fiber,graphene platelet,and ultra-high molecular weight polyethylene(UHMWPE).Friction tests of TPU based-composites against copper countersurface were carried out in water to mimic the actual operating conditions of the *** of the resulting contacts were in the boundary lubrication regime,in which friction was attributed to both contact mechanics of asperities as well as water *** results show that the viscoelasticity of TPU has a considerable impact on its tribological *** lubrication at 50°C promotes the softening of polymer surface material during sliding,resulting in higher fluctuation in the coefficient of friction and wear *** is attributed to the reduced thermomechanical *** addition,Schallamach waviness is observed on worn *** tribological properties of TPU are significantly improved by the inclusion of carbon fiber,graphene platelet,and *** formation of graphene transfer-layers and UHMWPE transfer film reduces friction and wear loss,while the inclusion of carbon fiber enhances wear resistance due to improved mechanical properties and load bearing capacity.

关键词： friction thermoplastic polyurethane(TPU) water-lubricated bearings graphene platelet carbon fibers ultra-high molecular weight polyethylene(UHMWPE)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

流水车间加工信息测度与控制

中国科学：技术科学 2024年第6期54卷 1091-1104页

作者：张志峰 janet David 刘俊桂林航天工业学院管理学院桂林541004 Department of Engineering Science University of OxfordOxford OX13PJUK 华中科技大学机械科学与工程学院武汉430074

流水车间加工信息的有效测度是实施加工批量决策的前提.当前多品种小批量生产信息控制研究多以生产技术、范式及智能算法等理论优化工作为主,极少开展生产的加工批量与其状态控制所需信息之间关系的研究,导致研究结论过于理论化而难以... 详细信息

流水车间加工信息的有效测度是实施加工批量决策的前提.当前多品种小批量生产信息控制研究多以生产技术、范式及智能算法等理论优化工作为主,极少开展生产的加工批量与其状态控制所需信息之间关系的研究,导致研究结论过于理论化而难以应用于现实生产.针对此研究局限性,本文从信息论角度出发,根据制造马尔科夫过程,定义流水车间的加工批量信息熵并解析其度量特性.进一步,构建流水车间加工批量信息熵函数,理论上证明其函数单调递减性.通过建立流水车间加工批次信息测度模型,确定生产线批次加工信息的组成结构,实现对工件加工所需信息量的测度.实证研究中,将平均调整准备时间、平均加工时间及完工时间等观测数据应用于实际企业的减速器生产线,做出不同参量与加工批量变化关系图,确定相关参数条件下生产线的最优加工批量.根据研究结果,提出有效减少管理与控制生产线所需信息量的对策,在验证所建熵模型科学性与有效性的同时,也为实际生产中的批量决策提供准确的现实指导.

关键词：流水车间加工批量熵函数信息测度

Limb Lengthening and Reconstruction Society orthopedic surgeons in the United States:An analysis of geographical distribution,academic,leadership,and demographic characteristics

维普期刊数据库

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

World Journal of Orthopedics 2024年第2期15卷 147-155页

作者： Amir Human Hoveidaei Reza Niakan Seyed Hossein Hosseini-Asl Abijith Annasamudram janet D Conway International Center for Limb Lengthening Rubin Institute for Advanced OrthopedicsSinai Hospital of BaltimoreBaltimoreMD 21215United States Student Research Committee Shiraz University of Medical SciencesShiraz 73Iran Students’Scientific Research Center Tehran University of Medical SciencesTehran ***Iran

BACKGROUND The Limb Lengthening and Reconstruction Society(LLRS)is a premier orthopedic specialty organization that promotes limb reconstruction for all *** membership characteristics,however,are poorly *** study delineates orthopedic surgeon LLRS members’demographic traits,academic achievement,leadership attainment,and geographical distribution across the United *** To inform aspiring orthopedic professionals,as well as to promote growth and diversity in both the LLRS organization and overarching *** This cross-sectional study examined United States LLRS members’academic,leadership,demographic,and geographical *** reviewing the 2023 LLRS member directory,Google search results were matched to the listings and appended to the compiled *** and ethnicity were evaluated visually utilizing retrieved *** Hirsch index(H-index)of academic activity,residency and fellowship training,other graduate degrees,leadership positions,practice type(academic or non-academic),and spoken languages were *** members per state and capita determined geographic *** Mann Whitney U test was applied to compare H-index between males and females,as well as to assess member differences pertaining to affiliation with academic vs non-academic practice *** The study included 101 orthopedic surgeons,78(77.23%)Caucasian and 23(22.77%)non-Caucasian,79(78.22%)male and 22(21.78%)*** with DO degrees comprised only 3.96%(4)of the cohort,while the vast majority held MDs[96.04%(97)].Mean H-index was 10.55,with male surgeons having a significantly higher score(P=0.002).Most orthopedic surgeons(88.12%,)practiced in academic *** those professionals who occupied leadership positions,14%were women,while 86%were ***,19(37.25%)United States regions and the District of Columbia lacked an LLRS-member orthopedic *** per capita rate across the United States was 0.30 LLRS orthopedic

关键词： Limb lengthening and reconstruction Orthopedic surgeon demographics Orthopedic surgeon societal membership Orthopedic fellowships

Polymer electrolytes for flexible zinc-air batteries:Recent progress and future directions

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Nano Research 2024年第7期17卷 6058-6079页

作者： Jing Wu Wen-Ya Wu Suxi Wang Dan Kai Enyi Ye Warintorn Thitsartarn janet Beng Hoon Tan Jianwei Xu Qingyu Yan Qiang Zhu Xian Jun Loh Institute of Sustainability for Chemicals Energy and Environment(ISCE2)Agency for ScienceTechnology and Research(A*STAR)1 Pesek RoadJurong IslandSingapore 627833Singapore Institute of Materials Research and Engineering(IMRE) Agency for ScienceTechnology and Research(A*STAR)2 Fusionopolis WayInnovis#08-03Singapore 138634Singapore School of Materials Science and Engineering Nanyang Technological University50 Nanyang AvenueSingapore 639798Singapore School of Chemistry Chemical Engineering and BiotechnologyNanyang Technological University21 Nanyang LinkSingapore 637371Singapore Department of Material Science and Engineering National University of Singapore9 Engineering Drive 1#03-09 EASingapore 117575Singapore

This review article delves into the development of electrolytes for flexible zinc-air batteries(FZABs),a critical component driving the advancement of flexible *** started by surveying the current advancements in electrolyte technologies,including solid-state and gel-based types,and their contributions to enhance the flexibility,efficiency,and durability of ***,we explored the challenges in this domain,focusing on maintaining electrolyte stability under mechanical stress,ensuring compatibility with flexible substrates,optimizing ion conductivity,and under harsh environmental ***,the key issues regarding interface details between electrolyte and the electrodes are covered as *** then discussed the future of electrolyte development in FZABs,highlighting potential avenues such as materials development,sustainability,in-situ studies,and battery *** review offers an in-depth overview of the advancements,challenges,and potential breakthroughs in creating electrolytes for FZABs over the past five *** serves as a guide for both researchers and industry professionals in this dynamic area.

关键词： flexible zinc-air batteries electrolyte polymer hydrogel electrolyte-electrode interface

Characterization of Extended Spectrum Beta-lactamase and Carbapenamase Producing Enterobacteriaceae Causing Urinary Tract Infection among Children in Kenya: A Cross-Sectional Study

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Advances in Microbiology 2024年第7期14卷 351-365页

作者： Rachael Wangeci Waithaka janet Kerubo Maranga Celestine Khalechi Makobe Department of Microbiology Jomo Kenyatta University of Agriculture and Technology Juja Kenya Gertrudes Childrens Hospital Nairobi Kenya

Introduction: Enterobacteriaceae causing urinary tract infections (UTI) have developed resistance to the commonly used antibiotics due to emergence of Extended Spectrum Beta-Lactamases (ESBLs) and Carbapenamase producing Enterobactericeae which are a public health problem worldwide. This study aims to determine the prevalence and characterize ESBLs and carbapenamase producing Enterobactericeae. Method: A cross-sectional study was carried out in Gertrude’s Children’s Hospital, Nairobi. 238 urine samples were collected from patients with urinary symptoms attending the outpatient department within the period 2020-2021. The urine were examined macroscopically and microscopically. Identification and antimicrobial susceptibility testing were done using VITEK® 2 Compact system (BioMérieux). Double disc synergy test and modified hodge tests were done as confirmatory tests for ESBLs and Carbapenamase phenotypes respectively. Polymerase Chain Reaction was used for the detection of blaCTX-M, blaTEM, blaSHV, blaKPC and blaOXA-48 genes. Results: From the 238 children sampled the prevalence of UTI caused by Enterobactericeae was 22.3%. The Enterobacteriaceae species isolated were Escherichia coli (84.9%), Klebsiella pneumoniae (5.66%), Proteus mirabillis (5.66%), Enterobacter aerogenes (1.89%) and Morganella morganii (1.89%). The isolated species were resistant to ampicillin. Meropenem had the highest susceptibility. Only E. coli species had the ESBLs (26.4%) and carbapenamase (1.9%) phenotypes. 100% had BlaCTX-M while 50% had blaTEM resistant gene. There was a significant association (p Conclusion: Ampicillin resistance resulted to use of alternative drugs and Meropenem was the drug of choice where increased resistance to the recommended drugs was noted. Further research on resistant genes is recommended.

关键词： Enterobactericeae Urinary Tract Infection Prevalence Beta Lactamases Polymerase Chain Reaction Children Outpatient Antimicrobial Resistance Phenotypes Escherichia coli

Materials and technology of Chinese jades dating to the Western Zhou period (1050―771 BCE)

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Technological Sciences) 2008年第4期51卷 467-480页

作者： janet G DOUGLAS Department of Conservation and Scientific Research Freer Gallery of Art / Arthur M. Sackler Gallery Smithsonian Institution

Excavated jades dating to the Western Zhou period (1050―771 BCE) from the Xi’an area in Shaanxi Province, China, and contemporaneous jades in the collections of the Arthur M. Sackler Gallery at the Smithsonian Institution have been studied to learn about the jade and stone materials and how they were worked during the Western Zhou period. Materials identification was carried out using a combination of techniques such as Fourier-transform infrared spectroscopy and X-ray diffraction. Tool marks were studied using stereomicroscopy and examination of mold impressions using scanning electron microscopy. All of these objects were pro- duced through simple processes involving solid drilling, riffling, and sharp point abrasion; and no evidence was found for the use of rotary tools for incising or sawing.

关键词： jade nephrite stone China Western Zhou scanning electron microscopy materials technology tool marks