检索结果-南通市图书馆

Increasing Powers in a Degenerate Parabolic Logistic Equation

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 Annals of Mathematics,Series B 2013年第2期34卷 277-294页

作者： jos francisco RODRIGUES Hugo TAVARES Department of Mathematics and CMAF Universidade de LisboaAvenida Professor Gama Pinto 21649-003 LisboaPortugal

The purpose of this paper is to study the asymptotic behavior of the positive solutions of the problem tu- △u=au-b（x）up in Ω×R＋,u（0）=u0,u（t ）｜ Ω=0, as p→ ＋∞, where Ω is a bounded domain, and b（x） is a nonnegative function. The authors deduce that the limiting configuration solves a parabolic obstacle problem, and afterwards fully describe its long time behavior.

关键词： Parabolic logistic equation Obstacle problem Positive solution Increasing power Subsolution and supersolution

Experimental study on the wear evolution of different PVD coated tools under milling operations of LDX2101 duplex stainless steel

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

Advances in Manufacturing 2023年第1期11卷 158-179页

作者： Vitor F.C.Sousa francisco J.G.Silva Ricardo Alexandre jose S.Fecheira Gustavo pinto Andresa Baptista ISEP-School of Engineering Polytechnic of PortoRua Dr.António Bernardino de Almeida4314200–072PortoPortugal INEGI-Driving Science and Innovation Rua Dr.Roberto Frias4004200–465PortoPortugal TEandM-Technology Engineering and MaterialsS.A.Parque Industrial do TaveiroLotes 41-423045–504TaveiroPortugal

Duplex stainless steels are being used on applications that require,especially,high corrosion resistance and overall good mechanical properties,such as the naval and oil-gas exploration *** components employed in these industries are usually obtained by machining,however,these alloys have low machinability when compared to conventional stainless *** this work,a study of the wear developed when milling duplex stainless-steel,LDX 2101,is going to be presented and evaluated,employing four types of milling tools with different geometries and coatings,while studying the influence of feed rate and cutting length in the wear of these *** used have been provided with two and four flutes,as well as three different coatings,namely:TiAlN,TiAlSiN and *** cutting behavior of these tools was analyzed;data relative to the cutting forces developed during the process were obtained;and roughness measurements of the machined surfaces were *** tools were then submitted to scanning electron microscope(SEM)analysis,enabling the identification of the wear mechanisms that tools were subjected to when machining this material,furthermore,the early stages of these mechanisms were also *** this work was done with the goal of relating the machining parameters and cutting force values obtained,identifying,and discussing the wear patterns that were observed in the coating and tools after the milling tests,providing further information on the machining of these alloys.

关键词： Duplex stainless-steel Milling Tool coatings Surface roughness Wear mechanisms

A numerical assessment of two geometries for reducing elbow erosion

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 2020年第2期18卷 117-133页

作者： Carlos Antonio Ribeiro Duarte francisco joséde Souza Diego Nei Venturi Martin Sommerfeld Department of Engineering Federal University of Goiás-Regional Catal(a)oAv.Dr.Lamartine Pinto de Avelar1120Catal(a)oGoiásBrazil School of Mechanical Engineering Federal University of Uberl(a)ndiaAv.Joāo Naves de(A)vila2121 Bloco 5PUberl(a)ndiaMinas GeraisBrazil Multiphase Flow Systems(MPS) Otto-von-Guericke-University MagdeburgZeppelinstraβe 1D-06130 Halle(Saale)Germany

Elbows in pneumatic conveying systems are normally prone to the erosive effects of conveyed *** are a number of solutions available to reduce such damage.A widely used geometric alternative for replacing the 90°elbow and reducing erosive wear is the plugged *** option,although less commonly used,is the vortex-chamber *** both cases,the effective reduction in erosion brought about is unclear,as it strongly depends on the operating *** present study assesses relative erosion among the plugged tee,vortex-chamber elbow,and standard elbow for a dilute gas-solid multiphase flow.A numerical model is employed to predict the penetration ratio and validated using experimental data for the plugged *** are run for the standard and vortex-chamber elbows and plugged tee under the same conditions to compare the mechanics involved and the relative erosion *** analysis uses variables relating to particle-wall interactions(impact angle,impact velocity,impact frequency)to illustrate the nature of the erosive process in each pipe *** general,the geometric configurations of both the plugged tee and vortex-chamber elbow promote changes in particle dynamics that reduce the rate of *** the basis of the relative erosion of the standard elbow,the plugged tee proves to be an interesting option in cases of a low mass loading,while the vortex-chamber elbow demonstrates its erosion reduction potential for higher mass loading ***,the advantages and disadvantages of each fitting are highlighted.

关键词： Relative erosion Plugged tee Erosion reduction Pipe fitting Computational fluid dynamics

Pro-atherosclerotic markers and cardiovascular risk factors one year after liver transplantation

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2014年第26期20卷 8667-8673页

作者： Mario Reis Alvares-da-Silva Claudia pinto Marques Souza de Oliveira josé Tadeu Stefano Hermes V Barbeiro Denise Barbeiro francisco G Soriano Alberto Queiroz Farias Flair josé Carrilho Luiz Augusto Carneiro D’Albuquerque Division of Liver and Gastrointestinal Transplant (LIM-37) Department of GastroenterologyUniversity of S?o Paulo School of Medicine Division of Gastroenterology Hospital de Clínicas de Porto AlegreUniversidade Federal do Rio Grande do SulRua Ramiro Barcellos90035-903 Porto AlegreBrazil Division of Clinical (LIM-07) Department of GastroenterologyUniversity of S?o Paulo School of Medicine Division of Emergency Medicine (LIM-51) University of S?o Paulo School of Medicine

AIM: To investigate pro-atherosclerotic markers (endothelial dysfunction and inflammation) in patients one year after liver transplantation.

关键词： Cell adhesion molecules Endothelial biomarkers Cardiovascular disease Nonalcoholic steatohepatitis Metabolic syndrome

Chemical Constituents from Caesalpinia férrea:Identification and ^(1)H and ^(13)C Resonance Assignment

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Analytical Chemistry 2014年第10期5卷 688-694页

作者： Islay Lima Magalhaes francisco Chagas Lima pinto Raimundo Braz Filho Daniele Alves Ferreira Telma Leda Gomes de Lemos francisco josé Queiroz Monte Departamento de Química Organica e Inorganica Universidade Federal do CearáFortalezaBrasil Laboratório de Ciencias Químicas Centro de Ciencias TecnológicasUniversidade Estadual do Norte FluminenseCampos dos GoytacazesBrasil

In a phytochemical investigation of Caesalpinia ferrea (Leguminosae), four aromatic compounds (1-4) have been isolated and identified. Their structures have been assigned based on data provided by spectroscopic techni... 详细信息

关键词： Caesalpinia ferrea Leguminosae Aromatic Compounds Spectral Studies

Production of Aflatoxins from Aspergillus flavus in Liquid Medium

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 Life Sciences 2013年第4期7卷 377-381页

作者： Maria Edite Bezerra da Rocha francisco das Chagas Oliveira Freire Icaro Gusmao pinto Vieira jose Mariados Santos Filho Fabio Erlan Feitosa maia Maria Izabel Florindo Guedes Davide Rondina Universidade Estadual do Ceara Avenida Paranjana 1700 CEP: 60740-000 Fortaleza Ceara Brasil Embrapa Agroindustria Tropical Rua Dra. Sara Mesquita 2270 CEP: 60.511-110 Fortaleza-CE Brasil

Aflatoxins are produced mainly by Aspergillus flavus and Aspergillus parasiticus, and can be found in many grains such as peanuts, soybeans and com. This study aimed to qualitatively and quantitatively evaluate the production of aflatoxin in liquid media using strains of Aspergillus flavus obtained from peanuts marketed in the city of Fortaleza, CEo Strains of Aspergillus flavus were inoculated into a liquid medium malt extract and after 2 days inoculated into a second medium containing sucrose 5%, MgSO4·7H20 0.1%, KH2PO4 1%, ZnSO4·7H2O 0.0176 g, and cultured for 3 more days. The media were kept at room temperature ranging from 24°C to 32 °C with agitation of 130 rpm and aeration of 4.17 Llmin. Qualitative analysis was performed by thin layer chromatography and quantitatively by high performance liquid chromatography with fluorescence detection, demonstrating the production of aflatoxin B I （588 mg/L） and B2 （929 mg/L）.

关键词： Peanut fungi micotoxins chromatography.

The Influence of Keratometry on Visual and Refractive Outcomes after Myopic LASER <i>in Situ</i>Keratomileusis

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Open Journal of Ophthalmology 2018年第2期8卷 84-90页

作者： Sara Frazã o Pedro Rodrigues Samuel Alves Ana Maria Carvalho josé maia Sê co Hugo Nogueira Instituto de Oftalmologia Dr. Gama pinto Lisbon Portugal

To evaluate the effect of preoperative keratometry on visual and refractive outcomes after Myopic LASER in Situ Keratomileusis (LASIK) in eyes with preoperative spherical equivalent (SE) of -6.00D or less. Material and Methods: A retrospective study enrolling clinical records of 482 eyes of 275 patients with myopia who underwent LASIK between 2009 and 2016. Subjects were grouped according to the degree of preoperative mean keratometry (Km), into three groups: Group 1 (Flat Cornea): Km ≤ 42.00 diopters (D);Group 2: 42.00 46.00D;Group 3 (Steep Cornea): Km ≥ 46.00D. To evaluate the prognostic impact of keratometry in Myopic LASIK, we considered the results measured at 6 months postoperatively, including uncorrected distance visual acuity (UDVA), postoperative sphere, cylinder, SE and its variation. Results: The mean preoperative SE was -3.91 ± 1.54D, ranging between -0.88 and -6.00D. The percentage of eyes achieving a postoperative SE of ±0.50D was 39.5%, 31.8% and 26% in groups 1, 2 and 3 respectively. Moreover, in group 3, 14.3% of the eyes had a residual SE of -2.00D or greater, contrasting with the groups 1 and 2 with only 6% - 7%. These results were found to be statistically significant. Concerning UDVA, eyes achieving 20/25 or more were 81.5%, 81.8% and 71.5%, and 20/50 or less were 6.7%, 6.2% and 11.7% in groups 1, 2 and 3 respectively. Conclusions: Myopic eyes with steeper corneas seem to have greater tendency to undercorrection, also presenting worse visual outcomes.

关键词： Myopia Astigmatism LASER in Situ Keratomileusis Keratometry Spherical Equivalent Flat Cornea Steep Cornea

Climatic Projections of Lightning in Southeastern Brazil Using CMIP5 Models in RCP’s Scenarios 4.5 and 8.5

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

American Journal of Climate Change 2017年第3期6卷 539-553页

作者： Ana Paula Paes dos Santos Osmar pinto Júnior Sérgio Rodrigo Quadros dos Santos francisco josé Lopes de Lima Everaldo Barreiros de Souza André Arruda Rodrigues de Morais Eldo E. ávila Analía Pedernera National Institute for Space Research (INPE) S&atilde o josé dos Campos Brazil Vale Institute of Technology (ITV) Belém Brazil National University of Cordoba (UNC) Córdoba Argentina

Given the high and increasing lightning incidence over the Southeast of Brazil and the various impacts that this phenomenon generates to society, there is a growing need in predicting its occurrence, in order to minimize its consequences. In this context, this work presents the development of a methodology for the projection of lightning in the State of S?o Paulo (Southeastern Brazil), using the HadGEM2-ES and CSIRO-Mk3.6 models in two IPCC climate change scenarios: RCP4.5 and RCP8.5. Since lightning is not an output variable of climate models, tests were carried out to evaluate the relationship between the observed data of oceanic and atmospheric fields, which are known as outputs of the models, and the lightning from the RINDAT and BrasilDAT detection networks. As result, a correlation of 0.84 was obtained. In the projections, it was verified that, while during a large portion of the current climate we observed events of lightning below the average, the future climate reveals the preponderance of anomalously above average events, both in the scenario of intermediate-low emissions (RCP4.5) and in the scenario of high emissions (RCP8.5), suggesting a change in the pattern of the lightning incidence in the State of S?o Paulo.

关键词： Lightning Climatic Projections Southeastern Brazil

Turbo-taxonomy to assemble a megadiverse lichen genus:seventy new species of Cora(Basidiomycota:Agaricales:Hygrophoraceae),honouring David Leslie Hawksworth’s seventieth birthday

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Fungal Diversity 2017年第3期84卷 139-207页

作者： Robert Lücking Manuela Dal Forno Bibiana Moncada Luis Fernando Coca Leidy Yasmín Vargas-Mendoza André Aptroot Laura Juliana Arias Betty Besal Frank Bungartz Diego Mauricio Cabrera-Amaya Marcela E.S.Cáceres josé Luis Chaves Sionara Eliasaro Martha Cecilia Gutiérrez Jesús E.Hernández Marin María de los Ángeles Herrera-Campos María E.Holgado-Rojas Harald Jonitz Martin Kukwa Fabiane Lucheta Santiago Madriñán Marcelo pinto Marcelli Suzana Maria de Azevedo Martins Joel A.Mercado-Díaz Jorge Alberto Molina Eduardo A.Morales Peter R.Nelson Freddy Nugra francisco Ortega Telma Paredes Ayda Lucía Patiño Rouchi Nadine Peláez-Pulido Rosa Emilia Pérez Pérez Gary B.Perlmutter Eimy Rivas-Plata Javier Robayo Camilo Rodríguez Diego Fernando Simijaca Edier Soto-Medina Adriano Afonso Spielmann Alejandra Suárez-Corredor Jean-Marc Torres Carlos Alberto Vargas Alba Yánez-Ayabaca Gothamie Weerakoon Karina Wilk Marcela Celis Pacheco Mauricio Diazgranados Grischa Brokamp Thomas Borsch Patrick M.Gillevet Masoumeh Sikaroodi James D.Lawrey Botanical Garden and Botanical Museum Berlin KöniginLuise-Straße 6-814195 BerlinGermany Science Education The Field Museum1400 South Lake ShoreChicagoIL 60605USA Department of Botany Smithsonian InstitutionNational Museum of Natural History10th St Constitution Ave NWWashingtonDC 20560USA Department of Environmental Science and Policy George Mason UniversityFairfaxVA 22030-4444USA Licenciatura en Biologı´a Universidad Distrital Francisco Jose´de CaldasCra.4 No.26D-54Torre de LaboratoriosHerbarioBogota´D.C.Colombia Herbario Universidad de Caldas(FAUC) Edificio BicentenarioCalle 65No.26-10ManizalesA.A.275CaldasColombia ABL Herbarium G.v.d.Veenstraat 1073762 XK SoestThe Netherlands Biologı´a Universidad del Quindı´oCarrera 15 Calle 12 NorteArmeniaQuindı´oColombia 120 Chavis Avenue LexingtonVA 24450USA Charles Darwin Foundation Puerto AyoraSanta Cruz IslandGala´pagosEcuador Schedestraße 8 53113 BonnGermany Jardı´n Bota´nico de Bogota´jose´Celestino Mutis Avenida Calle 63 No.68-95Bogota´D.C.Colombia Departamento de Biocieˆncias Universidade Federal de SergipeAvenida Vereador Olı´mpio Grandes/n.ItabaianaCEP:49.500-000 SergipeBrazil Laboratorio de Hongos Instituto Nacional de Biodiversidad(INBio)Apdo.22-3100Santo Domingo de HerediaCosta Rica Departamento de Botaˆnica Universidade Federal do Parana´Campus Polite´cnicoSetor de Cieˆncias Biolo´gicasAv.Cel.Francisco H.dos Santoss/nJardim das Ame´ricas81531-980 CuritibaPRBrazil Ingenierı´a Ambiental Universidad Distrital Francisco Jose´de CaldasCarrera 5 Este No.15-82Av.CircumvalarBogota´D.C.Colombia Instituto Experimental Jardı´n Bota´nico Dr.Tobı´as Lasser Centro de Investigacio´n y DesarrolloUniversidad Central de VenezuelaAve.Salvador AllendeJardı´n Bota´nico de CaracasApartado#2156Caracas 1010-AVenezuela Departamento de Bota´nica Instituto de Biologı´aUniversidad Nacional Auto´noma de Me´xicoApartado Postal 70-36704510 Ciudad De Me´xicoMexico Facultad de Ciencias Escuela Profesional de Biologı´aUniv

Following a large-scale phylogenetic study of the lichenized genus Cora(Basidiomycota:Agaricales:Hygrophoraceae),we formally describe 70 new species,honouring the seventieth birthday of David Leslie Hawksworth,one of the preeminent figures in mycology and lichenology in the past 50 *** on an updated phylogeny using the ITS fungal barcoding locus,we now recognize 189 taxa in a genus that until recently was considered to represent a single species;including this contribution,92 of these are formally recognized,including five taxa based on historical names or collections that have not been *** of Cora can be recognized by a combination of morphological(size,colour,lobe configuration,surface hairs,hymenophore size and shape),anatomical(thallus thickness,cortex structure,photobiont type,hyphal papillae),and ecogeographical features(substrate,habitat,distribution),and a keytable allowing the identification of all accepted taxa is *** new species are:Cora accipiter Moncada,Madrin˜a´n&Lücking ***.,*** Moncada,Soto-Medina&Lücking ***.,*** Moncada,Dal Forno&Lücking ***.,*** Dal Forno,Chaves&Lücking ***.,*** Moncada,***ı´guez&Lücking ***.,*** Lücking,Moncada&*** ***.,*** Moncada,Ya´nez-Ayabaca&Lücking ***.,*** Moncada,Patin˜o&Lücking ***.,*** Lücking,***&Dal Forno ***.,*** Holgado,Rivas Plata&Perlmutter ***.,*** Dal Forno,Eliasaro&Spielmann ***.,*** Nugra,Dal Forno&Lücking ***.,*** Lücking,Martins&Lucheta ***.,*** Moncada,R.-***´rez&Lücking ***.,*** Moncada,***.&Lücking ***.,*** Moncada,CabreraAmaya&Lücking ***.,*** Moncada,R.-***´rez&***.,*** Lücking,***&Dal Forno ***.,*** Moncada,***´rez-Corredor&Lücking ***.,*** Moncada,***&Lücking ***.,***

关键词： Bolivia Citizen science Chile Mexico Puerto Rico Sri Lanka