检索结果-南通市图书馆

FeNb在钢液中的溶化行为及在钢包精炼过程中提高Nb收得率的最佳工艺

在线全文

学校读者我要写书评

暂无评论

世界钢铁 2010年第6期10卷 44-48+58页

作者： Edmundo Burgos Cruz Daniel Pallos Fridman Marcelo C Carboni Rogério Contato Guimares marcos a stuart nogueira Ferdinando Luiz Cavallante 王厚昕巴西矿冶公司

阐述了标准铌铁(FeNb)的微观组织特性及其溶入钢液中的研究结果。在实验室的感应炉中进行了不同温度下的非连续试验,分析了固相FeNb与钢液凝固层界面的微观组织,并与原始FeNb粒子的微观组织进行了对比。这些试验研究结果可以阐释FeNb的... 详细信息

阐述了标准铌铁(FeNb)的微观组织特性及其溶入钢液中的研究结果。在实验室的感应炉中进行了不同温度下的非连续试验,分析了固相FeNb与钢液凝固层界面的微观组织,并与原始FeNb粒子的微观组织进行了对比。这些试验研究结果可以阐释FeNb的溶解机制和它在不同炼钢温度下的融入动力学条件。标准FeNb在钢水中溶解的试验结果证实FeNb颗粒的溶解速率高于有关文献中报告的结果,它们认为FeNb粒子的熔化温度高(>1600℃),所以在其模型中假定FeNb的溶解仅是通过固相粒子的扩散实现。本项工作得到的试验证据为标准FeNb的溶解机理提供了一种新的说法:在1500～1510℃受其共晶区的熔化行为控制,在1530～1575℃温度范围内则由初始板条相的熔化行为所主导,也就是说,均低于1600℃左右的炼钢温度。根据这些研究结果和炼钢厂已有的生产经验,对于微合金化钢在二次精炼阶段加入FeNb推荐了最优的工艺。

关键词： FeNb 铌铁溶解微合金化钢炼钢

Niobium in Microalloyed Steels Unchallenged for Its Main Applications

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2011年第S1期18卷 57-65页

作者： nogueira marcos A stuart Carneiro Tadeu Companhia Brasileira de Metalurgia e Minerao Technical DirectorSao PauloBrazil Companhia Brasileira de Metalurgia e Minerao Managing DirectorSao PauloBrazil

During the past five decades niobium has emerged as the most important microalloying element in high strength *** first theories to explain its role were presented in the seminal publications of Woodhead,Morrison and *** niobium microalloyed steels are unchallenged for their main *** examples include linepipe for gas transportation,automotive steels used in body-in-white and structural parts,shipbuilding,steel towers and steel structures in civil construction that exhibit better fire resistance and seismic load *** technology for steelmaking helped emphasize the superior overall properties that can be attained with the use of *** linepipe is the best example of cleaner steel with carbon levels below 0.05% manufactured *** niobium microalloyed steels present the optimal balance of strength,toughness,weldability and *** paper describes the evolution of the technology associated with niobium in microalloyed steels,technology that secured its status as the efficient solution to solving today’s challenges:safety,energy efficiency and environmental *** paper also presents evidence that enhances the case that there is a secure,stable,long-term supply of the ferroniobium used to manufacture these steels.

关键词： Niobium in Microalloyed Steels Unchallenged for Its Main Applications

Dissolution of FeNb in liquid steel and best practices to increase niobium recovery during ladle refining

在线全文

学校读者我要写书评

暂无评论

Baosteel Technical Research 2010年第S1期4卷 19-页

作者： Edmundo Burgos CRUZ Daniel Pallos FRIDMAN Marcelo C CARBONI Rogerio Contato GUIMARAES marcos a stuart nogueira Ferdinando Luiz CAVALLANTE CBMM Araxa MGBrasil CBMM Sao Paulo SPBrasil Sao Paulo Polytechnic School Brasil

This paper presents a microstructural characterization of standard ferroniobium(FeNb) and a study of its dissolution in *** dissolution trials at different temperatures were carried out in a laboratory induction *** microstructure at the interface between solid FeNb and frozen steel was analyzed and compared with the original FeNb *** results allowed clarifying both the FeNb dissolution mechanism and its incorporation kinetics at steelmaking *** results from the dissolution of standard FeNb in liquid steel proved that the dissolution rates of FeNb particles were higher than those reported in the pertinent literature,where models assume that FeNb dissolves only by the diffusion of solid particles due to its high melting temperatures(over 1 600℃).Most recent FeNb phase diagrams and DTA analyses have shown that standard FeNb begins to melt down below 1 600℃.The experimental evidences in this work have led to the adoption of a new description of the dissolution mechanism whereby standard FeNb dissolves predominantly by the melting of its eutectic zones at 1500℃to 1510℃and,later on,by the melting of the primary laths between 1530℃and 1575℃,i.e.,below the steelmaking temperatures of around 1 600℃.Based on these results and on previous melting-shop experience,this paper recommends the best practices for the addition of FeNb during the microalloyed steels secondary refining phase.

关键词： FeNb ferroniobium dissolution microalloyed steel steelmaking

CeO_(2)-Nb_(2)O_(5)photocatalysts for degradation of organic pollutants in water

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2020年第3期39卷 230-240页

作者： Nathália Pereira Ferraz Andre Esteves nogueira Francielle Candian Firmino marcos Vanessa Aguiar Machado Rene Rojas Rocca Elisabete Moreira Assaf Yvan Jesus Olortiga Asencios Institute of Marine Science Federal University of Sao PauloSantosSP11030-100Brazil Brazilian Center for Research in Energy and Materials(CNPEM) CampinasSP13083-970Brazil Sao Carlos Institute of Chemistry University of Sao PauloSao CarlosSP13566-590Brazil

The photocatalytic properties of CeO2-Nb2O5 photocatalysts in heterogeneous photocatalysis(under ultraviolet and visible radiation)and in Fenton-like process were *** blue dye(MB)and phenol(Ph)were used as models of pollutant molecules for these reactions,and the photocatalysts were characterized by X-ray diffraction(XRD),diffuse reflectance spectroscopy(DRS),scanning electron microscopy(SEM),energy-dispersive X-ray spectroscopy(EDX)and thermally stimulated luminescence(TL).The results indicated that the addition of CeO2(0.3 wt%,1.0 wt%and 2.0 wt%)to Nb2O5 sensitized the resultant materials,increasing light absorption in the visible ***,there is a suitable formulation of CeO2-Nb2O5 photocatalysts to improve each photocatalytic *** heterogeneous photocatalysis,the addition of small CeO2 quantities to Nb2O5 was enough to improve the photocatalytic activity of CeO2-Nb2O5 photocatalysts(The best composition reported was CeO20.3 wt%.).The effectiveness of the catalyst was explained by the decrease in the number of trapping and luminescence centers in the conduction band of the material after the addition of CeO2 to Nb2O5,but a large amount of CeO2 decreased the number of trapping,luminescent and active centers to a large ***,in a Fenton-like process,the addition of CeO2 to Nb2O5 was favorable in all the proportions studied.(The best composition was 2.0 wt%CeO2.)In this case,the effectiveness was explained by the influence of the adsorption process(adsorption-triggered process),and the interactions between H2 O2 and Ce3+of the CeO2 in each photocatalyst thus formed surface peroxide species O22-,which induced the removal of the organic molecules under visible light.

关键词： Advanced oxidation process Photocatalysts Nb_(2)O_(5) CeO_(2) Phenol Methylene blue

Phytochemical Analysis and Antifungal Activity of Extracts from Leaves and Fruit Residues of Brazilian Savanna Plants Aiming Its Use as Safe Fungicides

在线全文

学校读者我要写书评

暂无评论

Natural Products and Bioprospecting 2016年第4期6卷 195-204页

作者： Caroline Alves Breda Alessandra Marcon Gasperini Vera Lucia Garcia Karin Maia Monteiro Giovana Anceski Bataglion marcos nogueira Eberlin Marta Cristina Teixeira Duarte School of Food Engineering State University of CampinasUNICAMPMonteiro Lobato Street80BaraōGeraldoCampinasSaōPaulo 13083-862Brazil Microbiology Division of Research Center for Chemistry Biology and Agriculture–CPQBAUniversity of CampinasUNICAMPAlexandre Cazelatto Street999BetelPaulı´niaSaöPaulo 13148-218Brazil Organic Chemistry and Pharmaceutical Division of Research Center for Chemistry Biology and Agriculture–CPQBAUniversity of CampinasUNICAMPAlexandre Cazelatto Street999BetelPaulíniaSaöPaulo 13148-218Brazil Pharmacology and Toxicology Division of Research Center for Chemistry Biology and Agriculture–CPQBAUniversity of CampinasUNICAMPAlexandre Cazelatto Street999BetelPaulíniaSaöPaulo 13148-218Brazil ThoMSon Mass Spectrometry Laboratory Institute of ChemistryState University of CampinasUNICAMPCampinasSaōPaulo 13084-971Brazil

The increasing demand for safe food without preservatives or pesticides residues has encouraged several studies on natural products with antifungal activity and low *** this study,ethanolic extracts from leaves and fruit residues(peel and seeds)of three Brazilian savanna species(Acrocomia aculeata,Campomanesia adamantium and Caryocar brasiliense)were evaluated against phytopathogenic ***,the most active extract was chemically characterized by ESI-MS and its oral acute toxicity was *** from ***(pequi)peel and leaves were active against Alternaria alternata,Alternaria solani and Venturia pirina with minimal inhibitory concentrations between 350 and 1000 lg/*** incorporated in solid media,these extracts extended the lag phase of *** and *** and reduced the growth rate of *** peel extract showed better antifungal activity and their ESI-MS analysis revealed the presence of substances widely reported as antifungal such as gallic acid,quinic acid,ellagic acid,glucogalin and *** oral acute toxicity was relatively low,being considered safe for use as a potential natural fungicide.

关键词： Brazilian savanna fruits Residues Natural fungicides Phytopathogens

Clinical and environmental isolates of Burkholderia pseudomallei from Brazil: Genotyping and detection of virulence gene

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2017年第10期10卷 945-951页

作者： Tereza de Jesus Pinheiro Gomes Bandeira Debora de Souza Collares Maia Castelo-Branco marcos Fabio Gadelha Rocha Rossana de Aguiar Cordeiro Crister Jose Ocadaque Manoel de Araújo Neto Paiva Raimunda Samia nogueira Brilhante Jose Júlio Costa Sidrim Specialized Medical Mycology Center Postgraduate Program in Medical Microbiology Federal University of Ceará Christus School of Medicine Postgraduate Program in Veterinary Sciences State University of Ceará Federal Institute of Education Science and Technology of Ceará

Objective: To evaluate the genetic diversity of clinical and environmental isolates of Burkholderia pseudomallei(***) recovered in Ceara, Brazil, and screen these isolates for the presence of type three secretion system virulence ***: Nineteen *** isolates(9 from clinical cases and 10 from soils)were *** amplified polymorphic DNA was performed with primers OPQ-2, OPQ-4 and OPQ-16 to evaluate the genetic diversity, and type three secretion system gene was detected through polymerase chain ***: Random amplified polymorphic DNA showed a genetic relatedness of approximately 50% among the tested *** isolates, which were grouped into two clades, of which the biggest ones comprised 18/19 isolates for primer OPQ-2, and 17/19 isolates for primer *** OPQ-4 grouped the isolates into three clades comprising 1/19, 3/19 and 15/19 ***, type three secretion system gene was detected in all tested ***: This is an effort to type *** strains from Ceara, which is important for better understanding this pathogen, contributing for the epidemiological surveillance of melioidosis in this endemic region.

关键词： Burkholderia pseudomallei Melioidosis RAPD TTSS gene

Analysing vaccine efficacy evaluated in phase 3 clinical trials carried out during outbreaks

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4期9卷 1027-1044页

作者： Francisco Antonio Bezerra Coutinho marcos Amaku Fernanda Castro Boulos Jose Alfredo de Sousa Moreira Joao Italo DiasFranca Julio Antonio do Amaral Eliana nogueira Castro de Barros Claudio Jose Struchiner Esper Jorge Kallas Eduardo Massad School of Medicine University of Sao PauloBrazil Instituto Butantan Sao PauloBrazil School of Applied Mathematics Fundacao Getulio VargasRio de JaneiroBrazil

In this paper we examine several definitions of vaccine efficacy(VE)that we found in the literature,for diseases that express themselves in outbreaks,that is,when the force of infection grows in time,reaches a maximum and then *** fact that the disease occurs in outbreaks results in several problems that we *** propose a mathematical model that allows the calculation of VE for several *** trials usually needs a large number of volunteers that must be ***,all volunteers should be enrolled in approximately the same time,but this is generally impossible for logistic reasons and they are enrolled in a fashion that can be replaced by a continuous density function(for example,a Gaussian function).The outbreak can also be replaced by a continuous density function,and the use of these density functions simplifies the ***,for example Gaussian functions,one of the problems one can immediately notice is that the peak of the two curves do not occur at the same *** model allows us to conclude:First,the calculated vaccine efficacy decreases when the force of infection increases;Second,the calculated vaccine efficacy decreases when the gap between the peak in the force of infection and the peak in the enrollment rate increases;Third,different trial protocols can be simulated with this model;different vaccine efficacy definitions can be calculated and in our simulations,all result are approximately the *** final,and perhaps most important conclusion of our model,is that vaccine efficacy calculated during outbreaks must be carefully examined and the best way we can suggest to overcome this problem is to stratify the enrolled volunteer's in a cohort-by-cohort basis and do the survival analysis for each cohort,or apply the Cox proportional hazards model for each cohort.

关键词： Vaccine efficacy Clinical trials Mathematical models Simulations Covid-19

Analyzing Brazilian Driver’s License Authenticity by Easy Ambient Sonic-Spray Ionization Mass Spectrometry

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 2016年第4期7卷 342-350页

作者： Deleon Nascimento Correa Eduardo Morgado Schmidt marcos Fernando Franco Jorge Jardim Zacca Werickson Fortunato de Carvalho Rocha Antony de Paula Barbosa Rodrigo Borges Wanderley de Souza marcos nogueira Eberlin ThoMSon Mass Spectrometry Laboratory Department of Analytical Chemistry Institute of Chemistry University of Campinas-UNICAMP Campinas Brazil Technical-Scientific Police Superintendency from Sao Paulo State Criminalistic Institute Sao Paulo Brazil Analítica Sao Paulo Brazil Brazilian Federal Police Scientific and Technical Department Brasília Brazil National Institute of Metrology Quality and Technology-INMETRO Duque de Caxias Brazil

Fast and unequivocal methods of questioned document analysis are essential in forensic science. Here, a desorption/ionization technique, EASI-MS, was assessed for its ability to investigate questioned driver’s licenses (DL). Two suspects DL, displaying the same personal data in the proper fields (name and ID numbers), but with different individual photos, showing similar impressions on microscopic analysis, and authentic standards documents specimens were used as test cases. Profiles from authentic DL surface were dominated by a set of few minor ions, mainly from the plasticizers bis(2-ethylhexyl)phthalate and dibutylphthalate. The seized suspect counterfeit DL on points from personal data and photo were, however, dominated by abundant diagnostic ions of m/z 463, 507, 551, 595, 639, 683, which confirmed counterfeiting. Surfynol® and Nonoxynol-9®, which are common constituents of inkjet printing, were detected in the counterfeiting areas by high-accuracy EASI(+)-FT-ICR MS. The EASI-MS technique is shown therefore to offer an attractive tool for forensic investigation of questioned documents.

关键词： Forensic Sciences Questioned Documents Ambient Mass Spectrometry Easy Ambient Sonic-Spray Ionization Mass Spectrometry EASI-MS

Chlamydoconidium-producing Trichophyton tonsurans: Atypical morphological features of strains causing tinea capitis in Ceará, Brazil

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Asian Pacific Journal of Tropical Medicine 2019年第8期12卷 380-384页

作者： Raimunda Samia nogueira Brilhante Germana Costa Paixao Jonathas Sales de Oliveira Vandbergue Santos Pereira marcos Fábio Gadelha Rocha Reginaldo Goncalves de Lima-Neto Débora de Souza Collares Maia Castelo-Branco Rossana de Aguiar Cordeiro JoséJúlio Costa Sidrim Specialized Medical Mycology Center Postgraduate Program in Medical MicrobiologyFederal University of CearáRua Nunes de Melo1315FortalezaBrazil Postgraduate Program in Veterinary Sciences State University of CearáAv.Dr.Silas Munguba1700FortalezaBrazil Department of Tropical Medicine Center for Health SciencesFederal University of PernambucoRecife-PEBrazil

Objective: To report atypical morphological features of Trichophyton(T.) tonsurans strains associated with tinea capitis. Methods: Eighty-two T. tonsurans strains isolated in Ceará, Brazil, were analyzed regarding macro and micromorphological features and nutritional patterns. Results: Fifty-two samples presented abundant chlamydoconidia, which were produced in chains. Macroscopically, these strains developed small glabrous colonies that were firmly attached to the surface of the culture medium, with few or no aerial mycelia and intense rusty yellow pigmentation. Seven strains did not grow with stimulus from thiamine. Samples were heterogeneous regarding urease production and none presented in vitro hair perforation. Conclusions: The observation of T. tonsurans strains with distinct phenotypic features indicates the need to revise the taxonomic criteria for routine identification of this dermatophyte.

关键词： Trichophyton tonsurans Chlamydoconidia Dermatophyte Phenotyping