检索结果-南通市图书馆

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

同方期刊数据库评论

在线全文

同方期刊数据库

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

Modeling neutral-atmospheric electromagnetic delays in a“big data”world

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

Geo-Spatial Information Science 2018年第2期21卷 75-79页

作者： marcelo c.Santos Thalia Nikolaidou Department of Geodesy and Geomatics Engineering University of New BrunswickFrederictonCanada

If left unmodeled,the delay suffered by electromagnetic waves while crossing the neutral atmosphere negatively affects Global Navigation Satellite System *** modeling of the delay has been carried out by means of empirical models formulated based on climatological information or using information extracted from numerical weather prediction(NWP)*** paper explores the potential use of meteorological information of several types that will become available with the increasing number of sensors(e.g.a cell phone,or the thermometer of a nearby smart home)in *** can we make use of these potentially huge datasets,which may help to provide the best possible representation of the neutral atmosphere at any given time,as readily and as accurately as possible?This situation falls in the realm of Big Data.A few potential scenarios,a sequential improvement of Marini mapping function coefficients,a self-feeding NWP,and near real-time empirical model updates,are discussed in this *** pros and cons of each approach are discussed in comparison with what is done *** indicate that they have potential for a positive contribution.

关键词： Global navigation satellite system(GNSS) big data neutral atmosphere

Protein tyrosine phosphorylation of the human sperm head during capacitation： immunolocalization and relationship with acquisition of sperm-fertilizing ability

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 Journal of Andrology 2010年第6期12卷 853-861页

作者： Arcangelo Barbonetti Maria Rosaria c. Vassallo Giuliana cordeschi Dimitrios Venetis Andrea carboni Alessandra Sperandio Giorgio Felzani Sandro Francavilla Felice Francavilla Andrology Unit Department of Internal Medicine University of L＇Aquila Coppito 67100 L＇Aquila Italy Istituto di Ricovero e cura a carattere Scientifico S.Raffaele Sulmona 67039 Italy

The occurrence of tyrosine phosphorylation （TP） in the sperm head during capacitation has been poorly investigated, and no data exist on the relationship of its dynamics with the acquisition of sperm fertilizing ability. This study localized TP of head proteins in human spermatozoa during capacitation and explored its relationship with acquisition of the ability to display progesterone （P）-stimulated acrosome reactions （ARs） and to penetrate zona-free hamster oocytes. By immunofluorescence, TP immunoreactivity was revealed in the acrosomal region of formaldehyde-fixed/unpermeabilized samples, whereas it was abolished in fixed/permeabilized samples, in which TP immunoreactivity was high in the principal piece. No TP immunoreaetivity was detectable in unfixed spermatozoa. Head TP immunoreactivity was localized externally to the acrosome, close to the cytoplasmic membrane, as assessed by transmission electron microscopy. The increase in head TP was an early event during capacitation, occurring within 1 h in capacitating conditions. At this time, the P-stimulated ARs were also increased, whereas egg penetration was as poor as in uncapacitated spermatozoa. At 5 h of capacitation, the extent of neither head TP nor the P-induced ARs were greater than that at 1 h, whereas egg penetration had significantly increased. Seminal plasma inhibited head TP, P-induced ARs and egg penetration. None of these inhibitory effects, unlike those on tail TP, were prevented by the cAMP analogue dbcAMP （N,2-O-dibutyryladenosine 3＇,5＇-cyclic monophosphate）. In conclusion, head TP is a subsurface event occurring early during capacitation and is closely related to acquisition of the ability to display P-stimulated ARs, whereas the ability to fuse with oolemma and to decondense is a later capacitation-related event.

关键词： acrosome reaction capacitation human spermatozoa sperm-oocyte fusion tyrosine phosphorylation

Tree structure and diversity of lowland Atlantic forest fragments：comparison of disturbed and undisturbed remnants

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 Forestry Research 2016年第3期27卷 605-609页

作者： Fabricio Alvim carvalho Joao marcelo Alvarenga Braga marcelo Trindade Nascimento Departamento de Botanica Universidade Federal de Juiz de Fora. Campus Universitario s/n Sao PedroJuiz de Fora-MG 36036-900 Brazil Instituto de Pesquisas do Jardim Botanico do Rio de Janeiro. Rio de Janeiro-RJ Brazil Laboratorio de ciencias Ambientais CBB Universidade Estadual do Norte Fluminense Campos dos Goytacazes-RJ 28013-602 Brazil

This study describes the tree community structure of three moist lowland Atlantic Forest fragments in Rio de Janeiro State, southeastern Brazil. Two fragments were disturbed and an undisturbed one was used as reference. Our hypothesis was that disturbed fragments show distinct structural patterns in comparison with undisturbed stands due to past disturbance practices and forest fragmentation. Four 100 ×5 m sampling plots were demarcated in each fragment and all live and dead trees with DBH c 5 cm were located, measured and identified. The results supported our hypothesis, due to the high values found for standing dead trees, an increase of dominance of a few pioneer species, lower values of large trees and species richness in disturbed fragments in comparison with the undisturbed one. The advanced fragmentation process in the Southern Brazilian lowland areas and the high species richness in undisturbed areas highlight these forest fragments as priority areas for conservation and management.

关键词： Phytosociology Tree community Forestfragmentation . Hotspot Brazil

MGMT and MLH1 methylation in Helicobacter pylori-infected children and adults

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 Gastroenterology 2013年第20期19卷 3043-3051页

作者： Marisa c Alvarez Juliana c Santos Nathália Maniezzo marcelo S Ladeira Artur Lc da Silva Isabel cA Scaletsky José Pedrazzoli Jr marcelo L Ribeiro Unidade Integrada de Farmacologia e Gastroenterologia Universidade So FranciscoBragan a Paulista 12916-900SPBrazil Programa de Pós Gradua o em Genética e Biologia Molecular State University of CampinasCampinas 13083-970SPBrazil Departamento de clínica Médica UNESPBotucatu 18618-970SPBrazil Departamento de Genética Universidade Federal do ParáBelém 68400-000PABrazil Departamento de Microbiologia Imunologia e ParasitologiaUniversidade Federal de So PauloSo Paulo 04021-001SPBrazil

AIM:To evaluate the association between Helicobacter pylori(***) infection and MLH1 and MGMT methylation and its relationship with microsatellite instability(MSI).METHODS:The methylation status of the MLH1 and MGMT promoter region was analysed by methylation specific methylation-polymerase chain reaction(MSPPcR) in gastric biopsy samples from uninfected or ***-infected children(n = 50),from adults with chronic gastritis(n = 97) and from adults with gastric cancer(n = 92).MLH1 and MGMT mRNA expression were measured by real-time PcR and normalised to a constitutive gene(β actin).MSI analysis was performed by screening MSI markers at 4 loci(Bat-25,Bat-26,D17S250 and D2S123) with PcR;PcR products were analysed by single strand conformation polymorphism followed by silver *** analyses were performed with either the χ 2 test with Yates continuity correction or Fisher's exact test,and statistical significance for expression analysis was assessed using an unpaired Student's ***:Methylation was not detected in the promoter regions of MLH1 and MGMT in gastric biopsy samples from children,regardless of *** infection *** MGMT promoter was methylated in 51% of chronic gastritis adult patients and was associated with *** infection(P c cancer patients,and the difference in the percentage of methylated samples between these patients and those from ***-infected chronic gastritis patients was statistically significant(P cies among ***-infected and non-infected chronic gastritis adult patients were 13% and 7%,*** observed methylation of the MLH1 promoter(39%) and increased MSI levels(68%) in samples from gastric cancer patients in comparison to samples from ***-infected adult chronic gastritis patients(P ctively).The frequency of promoter methylation for both genes was higher in gastric cancer sam

关键词： Helicobacter pylori Microsatellite instability Promoter methylation MLH1 MGMT Gastric cancer

Hepatic perivascular epithelioid cell tumors:Benign,malignant,and uncertain malignant potential

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 2024年第18期30卷 2374-2378页

作者： marcelo Fabián Amante División Patología Hospital General de Agudos Cosme ArgerichBuenos Aires C1155AHAArgentina División Patología Hospital Alemán de Buenos AiresBuenos Aires C1155AHAArgentina

In 2013,the World Health Organization defined perivascular epithelioid cell tumor(PEcoma)as“a mesenchymal tumor which shows a local association with vessel walls and usually expresses melanocyte and smooth muscle markers.”This generic definition seems to better fit the PEcoma family,which includes angiomyolipoma,clear cell sugar tumor of the lung,lymphangioleiomyomatosis,and a group of histologically and immunophenotypically similar tumors that include primary extrapulmonary sugar tumor and clear cell myomelanocytic *** cell tumors with this immunophenotypic pattern have also had their malignant variants *** localizing to the liver,preoperative radiological diagnosis has proven to be very difficult,and most patients have been diagnosed with hepatocellular carcinoma,focal nodular hyperplasia,hemangioma,or hepatic adenoma based on imaging *** of a malignant variant of the liver have been ***,reports of malignant variants of these lesions have increased in recent ***,we support the use of the Folpe criteria,which in 2005 established the criteria for categorizing a PEcoma as benign,malignant,or of uncertain malignant *** they are not considered ideal,they currently seem to be the best approach and could be used for the categorization of liver tumors.

关键词： PEcomas Liver Pathology Malignant Benign Uncertain malignant potential

Direct recycling of Li-ion batteries from cell to pack level:challenges and prospects on technology,scalability,sustainability,and economics

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

carbon Energy 2024年第6期6卷 1-39页

作者： Joseph Jegan Roy Do Minh Phuong Vivek Verma Richa chaudhary Michael carboni Daniel Meyer Bin cao Madhavi Srinivasan Energy Research Institute@NTU(ERI@N) SCARCE LaboratoryNanyang Technological UniversitySingaporeSingapore School of Materials Science and Engineering Nanyang Technological UniversitySingaporeSingapore cEA CNRSENSCMUniversity of MontpellierUMR 5257(ICSM)Bagnols-sur-Cèze CedexFrance School of civil and Environmental Engineering Nanyang Technological UniversitySingaporeSingapore

Direct recycling is a novel approach to overcoming the drawbacks of conventional lithium-ion battery(LIB)recycling processes and has gained considerable attention from the academic and industrial sectors in recent *** primary objective of directly recycling LIBs is to efficiently recover and restore the active electrode materials and other components in the solid phase while retaining electrochemical *** technology's advantages over traditional pyrometallurgy and hydrometallurgy are costeffectiveness,energy efficiency,and sustainability,and it preserves the material structure and morphology and can shorten the overall recycling *** review extensively discusses the advancements in the direct recycling of LIBs,including battery sorting,pretreatment processes,separation of cathode and anode materials,and regeneration and quality enhancement of electrode *** encompasses various approaches to successfully regenerate high-value electrode materials and streamlining the recovery process without compromising their electrochemical ***,we highlight key challenges in direct recycling when scaled from lab to industries in four perspectives:(1)battery design,(2)disassembling,(3)electrode delamination,and(4)commercialization and *** on these challenges and changing market trends,a few strategies are discussed to aid direct recycling efforts,such as binders,electrolyte selection,and alternative battery designs;and recent transitions and technological advancements in the battery industry are presented.

关键词： battery design cathode regeneration direct recycling graphite recycling lithium-ion battery,scaling-up

Going beyond 1000000 resolved points in a Brillouin distributed fiber sensor: theoretical analysis and experimental demonstration

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Light(Science & Applications) 2016年第1期5卷 788-795页

作者： Andrey Denisov marcelo A Soto Luc Thévenaz EPFL Swiss Federal Institute of Technology Group for Fiber Optics(GFO)SCI-STI-LTStation 11CH-1015 LausanneSwitzerland

Distributed fiber sensing possesses the unique ability to measure the distributed profile of an environmental quantity along many tens of kilometers with spatial resolutions in the meter or even centimeter *** feature enables distributed sensors to provide a large number of resolved points using a single optical ***,in current systems,this number has remained constrained to a few hundreds of thousands due to the finite signal-to-noise ratio(SNR)of the measurements,which imposes significant challenges in the development of more performing ***,we propose and experimentally demonstrate an ultimately optimized distributed fiber sensor capable of resolving 2100000 independent points,which corresponds to a one-orderof-magnitude improvement compared to the *** a Brillouin distributed fiber sensor based on phase-modulation correlation-domain analysis combined with temporal gating of the pump and time-domain acquisition,a spatial resolution of 8.3 mm is demonstrated over a distance of 17.5 *** sensor design addresses the most relevant factors impacting the SNR and the performance of medium-to-long range sensors as well as of sub-meter spatial resolution *** step record in the number of resolved points could be reached due to two theoretical models proposed and experimentally validated in this study:one model describes the spatial resolution of the system and its relation with the sampling interval,and the other describes the amplitude response of the sensor,providing an accurate estimation of the SNR of the measurements.

关键词： distributed fiber sensors optical fibers stimulated Brillouin scattering

Arabidopsis photoperiodic regulator cONSTANS feeds back to control the circadian clock

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Molecular Plant 2024年第9期17卷 1338-1340页

作者： Abril San Martin marcelo Javier Yanovsky Instituto de Investigaciones Bioquimicas de Buenos Aires(Fundacion Instituto Leloir-cONIcET) Av.Patricias Argentinas 435Buenos Aires C1405BWEAraentina

Human beings live in a world defined by daily cycles of light and darkness caused by the Earth’s rotation around its ***,like most living organisms,have evolved internal circadian clocks that time biological processes in anticipation of these daily environmental changes(Young and Kay,2001).The plant clock relies on core genes encoding transcription factors(TFs),which regulate each other’s expression through intricate networks of interlocking transcriptional-translational feedback loops(Nohales and Kay,2016).These loops ultimately control the expression of thousands of genes,allowing plants to adapt to daily fluctuations in light,temperature,and humidity(covington et al.,2008).In addition to daily rhythms,the Earth experiences yearly seasonal cycles marked by longer,warmer days in spring and summer,followed by shorter,cooler days in autumn and *** changes in day length and temperature intensify with distance from the ***,the ability of plants to adjust their growth and development in anticipation of seasonal changes determines their latitudinal distribution(McMillan,1960).

关键词： circadian seasonal Arabidopsis