检索结果-南通市图书馆

Design multifunctional Mg–Zr coatings regulating Mg alloy bioabsorption

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第4期12卷 1461-1478页

作者： Zohra Benzarti Sandesh Itani JoséDavid Castro Sandra Carvalho Ana Sofia ramos University of Coimbra CEMMPREARISEDepartment of Mechanical EngineeringRua Luís Reis Santos3030-788CoimbraPortugal Laboratory of Multifunctional Materials and Applications(LaMMA) Department of PhysicsFaculty of Sciences of SfaxUniversity of SfaxSoukra Road km 3.5B.P.1171Sfax3000Tunisia

Magnesium(Mg)alloys are widely used for temporary bone implants due to their favorable biodegradability,cytocompatibility,hemocompatibility,and close mechanical properties to ***,rapid degradation and inadequate strength limit their *** overcome this,the direct current magnetron sputtering technique is employed for surface coating in Mg-based alloys using various zirconium(Zr)*** approach presents a promising strategy for simultaneously improving corrosion resistance,maintaining biocompatibility,and enhancing strength without compromising *** leveraging Mg’s inherent biodegradability,it has the potential to minimize the need for secondary surgeries,thereby reducing costs and *** paper is a systematic study aimed at understanding the corrosion mechanisms of Mg–Zr coatings,denoted Mg-xZr(x=0–5 at.%).Zr-doped coatings exhibited columnar growth leading to denser and refined structures with increasing Zr *** analysis confirmed the presence of the Mg(00.2)basal plane,shifting towards higher angles(1.15°)with 5 at.%Zr doping due to lattice parameter changes(i.e.,decrease and increase of“c”and“a”lattice parameters,respectively).Mg–Zr coatings exhibited“liquidphilic”behavior,while Young’s modulus retained a steady value around 80 GPa across all ***,the hardness has significantly improved across all samples’coating,reaching the highest value of(2.2±0.3)GPa for 5 at.%*** testing in simulated body fluid(SBF)at 37℃ revealed a significant enhancement in corrosion resistance for Mg–Zr coatings containing 1.0–3.4 at.%*** with the 5 at.%Zr coating which exhibited a corrosion rate of 32 mm/year,these coatings displayed lower corrosion rates,ranging from 1 to 12 mm/*** synergistic enhancement in mechanical properties and corrosion resistance,achieved with 2.0–3.4 at.%Zr,suggests potential ability for reducing stress shielding and controlled degradation performance,and consequentl

关键词： Mg-Zr coatings Magnetron sputtering Nanoindentation Corrosion resistance Bone implants

Influence of train speed and its mitigation measures in the short-and long-term performance of a ballastless transition zone

在线全文

学校读者我要写书评

暂无评论

Railway Engineering Science 2023年第4期31卷 309-324页

作者： Ana ramos Rui Calçada António Gomes Correia Department of Civil Engineering Faculty of EngineeringUniversity of PortoCONSTRUCT-LESEPortoPortugal Department of Civil Engineering University of MinhoISISEGuimarãesPortugal

The ballastless track is nowadays the most popular railway system due to the required low number of maintenance opera-tions and costs,despite the high *** gradual change from ballasted to ballastless tracks has been occurring in Asia,but also in Europe,increasing the number of transition *** transition zones are a special area of the railway networks where there is an accelerated process of track degradation,which is a major concern of the railway infrastructure ***,the accurate prediction of the short-and long-term performance of ballastless tracks in transition zones is an important topic in the current paradigm of building/rehabilitating high-speed *** work purposes the development of an advanced 3D model to study the global performance of a ballastless track in an embankment-tunnel transition zone considering the influence of the train speed(220,360,500,and 600 km/h).Moreover,a mitigation measure is also adopted to reduce the stress and displacements levels of the track in the transition.A resilient mat placed in the tunnel and embank-ment aims to soften the *** behaviour of the track with the resilient mat is evaluated considering the influence of the train speed,with special attention regarding the critical *** used methodology is a novel and hybrid approach that allows including short-term and long-term performance,through the development of a powerful 3D model combined with the implementation of a calibrated empirical permanent deformation model.

关键词： Ballastless track Train speed Numerical modelling Transition zone Critical speed

在线全文

学校读者我要写书评

暂无评论

Communications in Theoretical Physics 2020年第7期72卷 104-110页

作者： F Ungan M K Bahar S Pal M E Mora-ramos Faculty of Technology Department of Optical EngineeringSivas Cumhuriyet University58140SivasTurkey Faculty of Science Department of PhysicsSivas Cumhuriyet University58140 SivasTurkey Department of Quality Assurance CQA(SA)DGQA Ichapur-Nawabganj24Pgs(North)743144West BengalIndia Centro de Investigación en Ciencias Instituto de Investigación en Ciencias Básicas y AplicadasUniversidad Autónoma del Estado de MorelosAv.Universidad 1001CP62209CuernavacaMorelosMexico Facultad de Ciencias Básicas Universidad de MedellínMedellinColombia

We present a theoretical study on the effects of intense laser field(ILF)and static electric field on the linear and nonlinear optical properties of a cylindrical quantum dot with Rosen-Morse axial potential under the framework of effective mass and parabolic band *** study also takes into account the effects of the structure parameters(η,V1,and R).The analytical expressions of the linear,third-order nonlinear and total optical absorption coefficients(TOACs)and the relative refractive index changes(RRICs)are obtained by using the compact-densitymatrix *** results of numerical calculations show that the resonant peak position of the TOACs and RRICs shifts towards lower energies and the magnitude of the peak increases with the effect of the static electric field and *** addition,it is observed that while the resonant energies of the TOACs and RRICs of system shift towards the higher(lower)energies with the enhancement ofη,V1,they decrease with the augmentation of ***,the findings of this study show that the optical properties of the structure can be adjusted by changing the magnitude of structure parameters and applied external fields.

关键词： cylindrical quantum dot nonlinear optical response intense laser field electric field

Two-neutron transfer reactions as a tool to study the interplay between shape coexistence and quantum phase transitions

在线全文

学校读者我要写书评

暂无评论

Chinese Physics C 2020年第12期44卷 103-113页

作者： J.E.García-ramos J.M.Arias A.Vitturi Departamento de Ciencias Integradas y Centro de Estudios Avanzados en Física Matemática y ComputaciónUniversidad de Huelva21071 HuelvaSpain Instituto Carlos I de Física Teórica y Computacional Universidad de GranadaFuentenueva s/n18071 GranadaSpain Departamento de Física Atómica Molecular y NuclearUniversidad de SevillaApdo.106541080 SevillaSpain Dipartimento di Fisica e Astronomia“Galileo Galilei” Universitádegli Studi di PadovaPadovaItaly

The atomic mass table presents zones where the structure of the states changes rapidly as a function of the neutron or proton *** them,notable examples are the A≈100 Zr region,the Pb region around the neutron midshell(N=104),and the N≈90 rare-earth *** observed phenomena can be understood in terms of either shape coexistence or quantum phase *** objective of this study is to find an observable that can distinguish between both shape coexistence and quantum phase *** an observable to be analyzed,we selected the two-neutron transfer intensity between the 0+states in the parent and daughter *** framework used for this study is the Interacting Boson Model(IBM),including its version with configuration mixing(IBM-CM).To generate wave functions of isotope chains of interest needed for calculating transfer intensities,previous systematic studies using IBM and IBM-CM were used without changing the *** results of two-neutron transfer intensities are presented for Zr,Hg,and Pt isotopic chains using ***,for Zr,Pt,and Sm isotopic chains,the results are presented using IBM with only a single configuration,i.e.,without using configuration *** Zr,the two-neutron transfer intensities between the ground states provide a clear observable,indicating that normal and intruder configurations coexist in the low-lying spectrum and cross at A=98→*** can help clarify whether shape coexistence induces a given quantum phase *** Pt,in which shape coexistence is present and the regular and intruder configurations cross for the ground state,there is almost no impact on the value of the two-neutron transfer *** is the situation with Hg,where the ground state always has a regular *** the Sm isotope chain,which is one of the quantum phase transition paradigms,the value of the two-neutron transfer intensity is affected strongly.

关键词： two nucleon transfer reactions shape coexistence quantum phase transition interacting boson model

Vertical stratification of bat assemblages in flooded and unflooded Amazonian forests

在线全文

学校读者我要写书评

暂无评论

Current Zoology 2010年第4期56卷 469-478页

作者： Maria Joo ramos PEREIRA Joo Tiago MARQUES Jorge M.PALMEIRIM Centro de Biologia Ambiental Departamento de Biologia Animal Faculdade de Ciências da Universidade de Lisboa Instituto de Desenvolvimento Sustentvel Mamirau

Tropical rainforests usually have multiple strata that results in a vertical stratification of ecological opportunities foranimals. We investigated if this stratification influences the way bats use the vertical space in flooded and unflooded forests of theCentral Amazon. Using mist-nets set in the canopy (17 to 35 m high) and in the understorey (0 to 3 m high) we sampled four sitesin upland unflooded forests (terra firme), three in forests seasonally flooded by nutrient-rich water (varzea), and three in forestsseasonally flooded by nutrient-poor water (igapo). Using rarefaction curves we found that species richness in the understorey andcanopy were very similar. An ordination analysis clearly separated the bat assemblages of the canopy from those of the understorey inboth flooded and unflooded habitats. Gleaning carnivores were clearly associated with the understorey, whereas frugivores wereabundant in both strata. Of the frugivores, Carollinae and some Stenodermatinae were understorey specialists, but several Stenodermatinaemostly used the canopy. The first group mainly includes species that, in general, feed on fruits of understorey shrubs,whereas the second group feed on figs and other canopy fruits. We conclude that vertical stratification in bat communities occurseven within forests with lower canopy heights, such as Amazonian seasonally flooded forests, and that the vertical distribution ofbat species is closely related to their diet and foraging behaviour.

关键词： Amazon Bats Chiroptera Vertical stratification Floodplain

Areas of research and clinical approaches to the study of liver abscess

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2017年第2期23卷 357-365页

作者： Gregorio González-Alcaide Jorge Peris José Manuel ramos Department of History of Science and Documentation University of Valencia Deparment of Internal Medicine Hospital Universitario Sant Joan d’Alacant Departament of Clinical Medicine Universidad Miguel Hernández de Elche Department of Internal Medicine Hospital General Universitario de Alicante

AIMTo analyze the research activity on liver abscess (LA) and identify the main topic clusters in the *** identified all documents using the medical subject heading “LA” indexed in the MEDLINE database between 2001 and 2015. We performed a descriptive bibliometric analysis, characterizing the evolution of scientific activity, the publication types of the documents, the document categories of clinical interest (case reports, clinical trials, evaluation studies, meta-analysis, observational studies, practice guidelines and validation studies) and the geographic distribution of the research. We also carried out an analysis of networks and research clusters in order to identify the main topic areas of *** search yielded a total of 1278 documents, showing a stable scientific production over the study period and a marked multidisciplinary nature. The research was dominated by case reports (65.9% of the documents analyzed). In terms of geographic distribution, researchers from the United States led in the number of signatures (n = 229), followed by those from Taiwan (n = 185), India (n = 145), Japan (n = 144), South Korea (n = 100), and China (n = 84). With regard to amebic LA, the top-producing countries were India and Mexico (n = 69 each), followed by the United States (n = 29). In the case of pyogenic LA, Taiwan Residents researchers led scientific production (n = 71), followed by the United States (n = 39) and China (n = 29). The most active areas of research in the field are diagnosis via computerized tomography scan, differential diagnosis with regard to liver cancer, treatment with antimicrobial agents, and Klebsiella infections (including bacteremia).CONCLUSIONClinical case reports associated with diagnosis and treatment are the main topic of study, highlighting the importance of this document type in advancing knowledge.

关键词： Liver abscess Cluster analysis Amebic abscess Pyogenic abscess Bibliometrics

Force criterion of different electrolytes in microchannel

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2009年第10期18卷 4349-4352页

作者：任玉坤闫辉姜洪源顾建忠 Antonio ramos School of Mechatronics Engineering Harbin Institute of Technology Department Electronica y Electromagnetismo Universidad de Sevilla Avda Reina Mercedes s/n Sevilla 41012 Spain

The control and handling of fluids is central to many applications of the lab-on-chip. This paper analyzes the basic theory of manipulating different electrolytes and finds the two-dimensional model. Coulomb force and dielectric force belonging to the body force of different electrolytes in the microchannel were analyzed. The force criterion at the interface was concluded, and testified by the specific example. Three basic equations were analyzed and applied to simulate the phenomenon. The force criterion was proved to be correct based on the simulation results.

关键词： force criterion basic theory specific example numerical simulation

Influence of bed elevation discordance on flow patterns and head losses in an open-channel confluence

在线全文

学校读者我要写书评

暂无评论

Water Science and Engineering 2019年第3期12卷 235-243页

作者： Pedro Xavier ramos Laurent Schindfessel Joao Pedro Pego Tom De Mulder Department of Civil Engineering Ghent University Ghent 9000 Belgium Faculty of Engineering University of Porto Porto 4200-465 Portugal

Confluences play a major role in the dynamics of networks of natural and man-made open channels, and field measurements on river confluences reveal that discordance in bed elevation is *** of schematized confluences with a step at the interface between the tributary and the main channel bed reveal that bed elevation discordance is an important additional control for the confluence *** study aimed to improve understanding of the influence of bed elevation discordance on the flow patterns and head losses in a right-angled confluence of an open channel with rectangular cross-sections.A large eddy simulation (LES)-based numerical model was set up and validated with experiments by *** configurations with different bed discordance ratios were *** results confirm that, with increasing bed elevation discordance, the tributary streamlines at the confluence interface deviate less from the geometrical confluence angle, the extent of the recirculation zone (RZ) gets smaller, the ratio of the water depth upstream to that downstream of the confluence decreases, and the water level depression *** bed elevation discordance also leads to the development of a large-scale structure in the lee of the *** the appearance of the large-scale structure, the reduced extent of the RZ and associated changes in flow deflection/contraction reduce total head losses experienced by the main channel with an increase of the bed discordance *** turns out that bed elevation discordance converts the lateral momentum from the tributary to streamwise momentum in the main channel more efficiently.

关键词： Open channel confluence Bed elevation discordance Three-dimensional numerical modelling Large eddy simulation Recirculation zone

Confounding response of macrofauna from a confluence of impacts: brine and sewage pollution

在线全文

学校读者我要写书评

暂无评论

Acta Oceanologica Sinica 2013年第10期32卷 74-81页

作者： Rodrigo Riera Fernando Tuya Myriam Rodríguez óscar Monterroso Eva ramos Centro de Investigaciones Medioambientales del Atlántico (CIMA SL) Arzobispo Elías Yanes 4438206 La LagunaTenerifeCanary IslandsSpain BIOGES University of Las Palmas de G.C.35017 Las Palmas de Gran CanariaCanary IslandsSpain

Throughout the shores of the world, a confluence of different sources of pollution is common, e.g., through outlets releasing brine, industrial, and domestic sewage. In this study, we assessed whether a combined disposal of domestic sewage and brine altered the patterns of abundance and assemblage structure of sub- tidal macrofauna inhabiting sandy seabeds on the south coast of Gran Canaria （Canary Islands, NE Atlantic Ocean）. Samples were collected in two surveys （May 2008 and January 2009） at three distances （0, 15, and 30 m） away from the discharge point. Macrofaunal abundances showed different patterns with varying proximity from the disposal point in the two surveys. In May 2008, lower abundances were observed at 0 m （53.89±46.82 ind.） than at 15 m （120±91.7 ind.） and 30 m （283.89±189.33 ind.） away from the dis- posal point. In January 2009, however, higher abundances were observed at 0 m （131.33±58.69 ind.） than at 30 m （100±24.44 ind.） and 15 m （84.78±58.39 ind.） away from the disposal point. Significant differ- ences in macrofaunal assemblage structure were found with varying proximity from the discharge point in both surveys. The effect of proximity from the disposal point was confounded by changes in sedimen- tary composition between surveys, which contributed to explain differences in macrofaunal abundances and assemblage structure with varying proximity from the discharge point. As a result, confounding driver- s of macrofaunal assemblage structure, here, changes in sediment composition, accounted for changes in macrofaunal abundances and assemblage structure with varying proximity from a combined disposal point of brine and sewage.

关键词： macrofauna amphipoda polychaeta brine sewage Canary Islands