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Dendritic Growth, Eutectic Features and Their Effects on Hardness of a Ternary Sn–Zn–Cu Solder Alloy

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Acta Metallurgica Sinica(English Letters) 2017年第6期30卷 528-540页

作者： Bismarck Luiz silva Rodrigo Valenzuela Reyes Amauri Garcia Joséeduardo Spinelli Department of Materials Engineering Federal University of Rio Grande do Norte-UFRNNatalRN 59078-970Brazil Department of Materials Engineering Federal University of Sao Carlos-UFSCarSao CarlosSP 13565-905Brazil Department of Manufacturing and Materials Engineering University of CampinasUNICAMPCampinasSP 13083-860Brazil

The present investigation is based on the results of a directionally solidified （DS） Sn-9 wt%Zn-2 wt%Cu alloy, including primary/secondary/tertiary dendrite arm spacings of the Sn-rich matrix, the morphologies of the eutectic mixture and the corresponding interphase spacing, the nature and proportion of the Cu-Zn intermetallic compound （IMC）. The main purpose is to establish interrelations of these microstructure features with experimental solidification thermal parameters, such as cooling rates and growth rates （v）, macrosegregation and hardness. Such interrelations are interesting for both industry and academy since they represent a tool permitting the preprogramming of final properties based on the design of the microstructure. In the case of Sn-Zn-Cu alloys, hardly anything is known about the combined effects of the length scale of the microstructure and fraction and distribution of the primary IMC on hardness. The alloy microstructure is composed of a β-Sn dendritic region, surrounded by a eutectic mixture of α-Zn and β-Sn phases and the γ-Cu5Zn8 IMC. The eutectic interphase spacing varies in the range 1.2-3.6 μm, with the α-Zn phase having a globular morphology for ν 〉 0.5 mm/s and a needle-like morphology for ν 〈 0.3 mm/s. A modified Hall-Petch-type experimental expression relating hardness to the interphase spacing is proposed.

关键词： Sn-Zn-Cu solder alloy Solidification Microstructure Eutectic morphology Hardness

Characterization of porous cobalt hexacyanoferrate and activated carbon electrodes under dynamic polarization conditions in a sodium-ion pseudocapacitor

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Journal of Energy Chemistry 2021年第3期30卷 53-62页

作者： Bruno Morandi Pires Willian Goncalves Nunes Bruno Guilherme Freitas Francisca Elenice Rodrigues oliveira Vera Katic Cristiane Barbieri Rodella Leonardo Morais da silva Hudson Zanin Advanced Energy Storage Division Manufacturing CroupCarbon Sci-Tech LabsCenter for Innovation on New EnergiesUniversity of CampinasCampinas 13083-852SPBrazil Brazilian Synchrotron Light Laboratory(LNLS/Brazilian Center of Energy and Materiab(CNPEM)) Campinas 13083-970SPBrazil Department of Chemistry Laboratory of Fundamental and Applied ElectrochemistryFederal University of Jequitinhonha and Mucuri's VatleyAlto dajacuba 39100-000Diamantina-MGBrazil

We report here the activated carbon and cobalt hexacyanoferrate composite,which is applied as the electrode materials in symmetric supercapacitors containing a 1.0 M Na_(2)SO_(4) aqueous *** novel material combines high specific surface area and electrochemical stability of activated carbon with the redox properties of cobalt hexacyanoferrate,resulting in maximum specific capacitance of 329 F g^(-1) with large voltage working window of 2.0 *** studies indicated that cobalt hexacyanoferrate introduces important pseudocapacitive properties accounting for the overall charge-storage process,especially when I<0.5 A g^(-1).At lower gravimetric currents(e.g.,0.05 A g^(-1))and up to 1.0 V,the presence of cobalt hexacyanoferrate improves the specific energy for more than 300%.In addition,to better understanding the energy storage process we also provided a careful investigation of the electrode materials under dynamic polarization conditions using the in situ Raman spectroscopy and synchrotron light Xray diffraction *** complementary findings were obtained in these *** believe that this novel electrode material is promising for applications regarding the energy-storage process in pseudocapacitors with long lifespan properties.

关键词： Operando studies Raman XRD synchrotron light Cobalt hexacyanoferrate Activated carbon High specific capacitance

Lithic soils in the semi-arid region of Brazil:edaphic characterization and susceptibility to erosion

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Journal of Arid Land 2022年第1期14卷 56-69页

作者： Carlos R PINHEIRO JUNIOR Conan A SALVADOR Tiago R TAVARES Marcel C ABREU Hugo S FAGUNDES Wilk S ALMEIda eduardo C silva NETO Lúcia H C ANJOS Marcos G PEREIRA Federal Rural University of Rio de Janeiro(UFRRJ) Department of SoilsSeropédicaRio de Janeiro 23890Brazil Center for Nuclear Energy in Agriculture(CENA) University of São Paulo(USP)PiracicabaSão Paulo 13416Brazil Federal Institute of Education Science and Technology of Rondônia(IFRO)Rural ZoneAriquemesRondônia 78930Brazil

Soils(Leptosols or Epileptic Regosols)with lithic contact at a depth of 50 cm occupy almost 20%of the Brazilian semi-arid *** lithic soils are susceptible to erosion due to faster saturation of water-holding capacity during rainfall,which accelerates the beginning of ***,erosion traits of lithic soils in the semi-arid region of Brazil are less *** aim of this study was to characterize the soil and landscape attributes in areas with Neossolos Litólicos(Entisols)in the Caatinga biome to identify region of high susceptibility to *** showed that the soils were characterized by a sandy texture,soil structure with poor development and low content of organic *** attributes increase susceptibility to erosion and reduce water storage capacity,especially in the states of Cearáand *** these states,the content of rock fragments in the soil reaches 790 g/*** contents of silt and fine sand,high silt/clay ratio,predominance of Leptosols and strong rainfall erosivity were observed in Piauíand northwestern Ceará.A very high degree of water erosion was observed in the states of Pernambuco and Paraí*** the low degree of erosion observed in the state of Bahia,it is highly susceptible to erosion due to the predominance of very shallow soils,rugged relief and high values of rainfall *** vulnerability was observed in the state of Alagoas because of its more smoothed relief,greater effective soil depth,thicker A horizon of soil and lower rainfall *** general,the characteristics that intensify the susceptibility to erosion in the Caatinga biome are those soil structures with poor development or without aggregation,low contents of organic carbon,high contents of silt and fine sand,high values of silt/clay ratio and rugged relief in some *** study collected information contributing to a better characterization of soils with lithic contact in the semi-arid region of *** addition,regions with

关键词： Caatinga biome drylands erosive processes leptosols soil degradation

Osmoregulators in Hymenaea courbaril and Hymenaea stigonocarpa under water stress and rehydration

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Journal of Forestry Research 2018年第6期29卷 1475-1479页

作者： Luma Castro de Souza Luana Moraes da Luz Je′ssica Taynara da silva Martins Candido Ferreira de oliveira Neto Juscelino Goncalves Palheta Tamires Borges de oliveira Ediane Conceicao Alves Risely Ferraz de Almeida Raimundo Leonardo Lima de oliveira Roberto Cezar Lobo da Costa Nariane Quaresma Vilhena Universidade estadual paulista ju′lio de mesquita filho JaboticabalSP 14884-900Brazil Universidade Federal Rural da Amazonia(UFRA) Campus CapanemaCapanema 68700-030Brazil Universidade Federal Rural da Amazonia Campus BelemBelem 66077-830Brazil Universidade Federal de Vicosa(UFV) Vicosa 36570-900Brazil Universidade Estadual Paulista Ju′lio de Mesquita Fiho(UNESP) Jaboticabal 14884-900Brazil Universidade do Estado do Para′(UEPA) Bele′m 66113-200Brazil

The objective of this work was to evaluate the effect of different water deficiency and rehydration levels on the concentrations of osmoregulators in two plant species（Hymenaea courbaril and H. Stigonocarpa） in the Amazon. We adopted a 2×5×5 factorial system,referring to 2 species（H. courbaril and H. stigonocarpa）and 5 stages of hydration and rehydration. The five hydration and rehydration stages were established in:（1）Control treatment E0;（2） Plants with 13 days of stress after incubation—E13;（3） Plants with 26 days of stress E26;（4）The plants that were established after 26 days after incubation and rehydrated for two days（RD2）;（5） rehydrated for two days（RD4）. The plants that were established after 26 days after incubation and rehydrated for four days. The experiment totaled fifty young plants with five *** measurements were performed at the beginning of the experiment（E0） at 13（E13） and 26（E26） days after the water stress, in which the plants were rehydrated,repeating the analyses after two（RD2） and four（RD4）days. Both species increased the sucrose concentration by18%, with a decrease of 52% in starch content. The RD4 time presented the highest mean starch concentration(0.19 mmol g-1 of the residue for H. courbaril and0.27 mmol g;of residue for H. stigonocarpa). Increased proline concentrations were recorded for controls until RD2 for both species. For glycine betaine, the highest increases in treatments E26 and RD2 were observed for the H. courbaril species. Our rehydration period was not sufficient for total recovery of pre-stress concentrations of all studied solutes.

关键词： Amazonia Water stress Osmotic adjustment Proline Sucrose

Impacted Lower Third Molar Fused with a Supernumerary Tooth—Diagnosis and Treatment Planning Using Cone-Beam Computed Tomography

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International Journal of Oral Science 2009年第4期1卷 224-228页

作者： Osny Ferreira-Junior Luciana Dorigatti de .＆.Aila Marcelo Bonifacio da silva Sampieri eduardo Dias- Ribeiro Wei-liang Chen Song Fan Department of Stomatology Dental School of Bauru University of Sao Paulo Bauru Sao Paulo Brazil Department of Stomatology the Second Affiliated Hospital Sun Yat-Sen University Guangzhou China

This paper reported a case of fusion between an impacted third molar and a supernumerary tooth, in which a surgical intervention was carried out, with the objective of removing the dental elements. The panoramic radiography was complemented by the Donovan＇s radiographic technique; but because of the proximity of the dental element to the mandibular ramus, it was not possible to have a final fusion diagnosis. Hence, the Cone-Beam Computed Tomography--which provides precise three- dimensional information--was used to determinate the fusion diagnosis and also to help in the surgical planning. In this case report we observed that the periapical, occlusal and panoramic were not able to show details which could only be examined through the cone-beam computed tomo- graphy.

关键词： third molar supernumerary tooth oral surgery,cone-beam computed tomography

Fatigue Strength Evaluation of Resin-Injected Bolted Connections Using Statistical Analysis

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Engineering 2017年第6期3卷 795-805页

作者： Jose Antonio Fonseca de oliveira Correia Bruno Alexandre silva Pedrosa Patricia Cordeiro Raposo Abilio Manuel Pinho De Jesus Helena Maria dos Santos Gervisio Grzegorz Stanislaw Lesiukc Carlos Alberto da silva Rebelo Rui Artur Bartolo Calcada Luis Alberto Proenca Simoes da silva Faculty of Engineering University of Porto Porto 4200-465 Portugal Institute for Sustainability and Innovation in Structural Engineering (ISISE) Department of Civil Engineering University of Coimbra Coimbra 3030-788 Portugal Department of Mechanics Materials Science and Engineering Faculty of Mechanical Engineering Wroclaw University of Technology Wroctaw 50-370 Poland

在对老旧的螺栓和铆接金属桥进行修补和加固时可以使用不同的方案。由于铆接链接技术目前并不常用,连接它需要特定的设备和熟练的工人。另一种解决方案是使用焊接。但是,老旧钢材的可焊性较差。螺栓是一种非常可行的替代解决方案,并且... 详细信息

在对老旧的螺栓和铆接金属桥进行修补和加固时可以使用不同的方案。由于铆接链接技术目前并不常用,连接它需要特定的设备和熟练的工人。另一种解决方案是使用焊接。但是,老旧钢材的可焊性较差。螺栓是一种非常可行的替代解决方案,并且常用于修复旧金属桥。装配螺栓的解决方案成本高昂,另一种方法是使用树脂灌注式螺栓。带有预紧力的树脂灌注式老旧螺栓连接的受力性能已经用准静态和蠕变试验进行了研究,然而,关于这些连接节点的滑移和疲劳行为的文献很少。本文概述了几位研究者的实验项目,旨在评估单侧受剪和双侧受剪的树脂灌注式螺栓连接的疲劳行为。对有预紧力的标准螺栓和有预紧力的树脂灌注式螺栓的连接节点的实验数据进行比较分析,显示后者的疲劳强度较低。但欧洲规范3(EC3)对树脂灌注式螺栓和标准螺栓的连接节点提出的疲劳强度曲线大致相同,这应得到足够的重视。此外,本研究还展示了使用黏结螺栓连接的可行性研究。最后的研究是用高强度低合金结构钢板和用于金属黏结的丙烯酸结构黏结剂进行的。针对两个实际工程案例,使用线性化边界及Castillo和Fernández-Canteli模型对疲劳实验数据进行统计分析。最终提出疲劳设计曲线,并与欧洲和北美规范中的几个设计建议进行比较。

关键词：疲劳连接结构加强 S-N曲线树脂灌注式螺栓

Sharp differentiation on the performance of plant functional groups across natural edges

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Journal of Plant Ecology 2019年第1期12卷 186-198页

作者： Evelyn da Fonseca Alecrim Bragion Gabriela Aparecida oliveira Coelho Flávia Freire de Siqueira Maria Uriarte eduardo van den Berg Department of Forest Engineering Federal University of LavrasCampus UniversitárioCaixa Postal 3037CEP 37200-000LavrasMGBrazil Department of Ecology Evolution and Environmental BiologyColumbia UniversityNew YorkNYUSA

Aims Gallery forests within grasslands have natural edges with open envi-ronments and offer a unique opportunity to examine how species performances vary across environmental ***,we asked if demographic rates of tree functional groups varied along the edge,if we could explain differences in plant strategies and performance through functional traits and which traits increase growth and sur-vival in natural *** We examine mortality and recruitment within the first 10 m of nat-ural edges of eight gallery forests using demographic data from five annual *** defined a priori plant strategies using tree functional groups:light demanding,pioneer and shade *** Findings The shade-tolerant group had the lowest mortality rates and basal area(BA)loss,while pioneer and light-demanding species had similar behavior for these *** survival and growth of functional groups were affected differently by the distance from the *** pioneer group survived more near the edge,while light-demanding and shade-tolerant groups toward the forest *** groups had higher growth in the *** differences could be explained by functional traits since most species have an acquisition strategy:higher specific leaf area and growth,lower leaf dry matter con-tent,lighter stem density,deeper crowns and less slender *** traits enhanced ***,mortality selected both strategies,but in distinct edge’s *** study showed that the high diversity found in natural edges can be explained by a niche and functional perspective,where differences in functional traits lead to differential performance along the environmental gradient.

关键词： edges diversity gradient niche hypothesis SLA LDMC

Microbial enzymatic stoichiometry and the acquisition of C, N,and P in soils under different land-use types in Braziliansemiarid

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Soil Ecology Letters 2023年第3期5卷 101-108页

作者： Erika Valente de Medeiros Érica de oliveira silva Gustavo Pereira Duda Mario Andrade Lira Junior Uemeson Josédos Santos Claude Hammecker Diogo Paes da Costa Fabio Fernando Araujo Arthur Prudêncio de Araujo Pereira Lucas William Mendes Ademir Sergio Ferreira Araujo Laboratory of Microbiology and Enzymology-LEMA Federal University of Agreste PernambucoGaranhuns 55292-270Brazil Federal Rural University of Pernambuco Rua Dom Manuel de Medeiross/nDois Irmãos52171-900RecifeBrazil Soil-Agrosystem-Hydrosystem Interaction Lab-LISAH Place Pierre Viala234060 MontpellierFrance Universidade do Oeste Paulista Presidente PrudenteSPBrazil Departamento de Ciência Do Solo Universidade Federal Do CearáFortalezaCEBrazil Center for Nuclear Energy in Agriculture University of Sao PauloPiracicabaSPBrazil Soil Quality Lab Agricultural Science CenterFederal University of PiauíTeresinaPI 60049-550Brazil

This study hypothesized that different land-use affect the microbial enzymatic stoichiometry and C-,N-,and P-acquisition in Brazilian semiarid ***,the enzymesβ-glucosidase(C-acquiring enzyme),urease(N-acquiring enzyme),and acid phosphatase(P-acquiring enzyme)were assessed in soil samples collected at 0−5 and 5−10 cm depth from a tropical dry forest,a protected area with Angico,a protected area with Ipê,scrub area,and an agricultural area with *** values of C-,N-,and P-acquiring enzymes were used to calculate the enzymatic C:N,C:P,and N:P *** values of C:P and N:P ratios were higher at 0−5 cm depth,while no significant variation,between soil depth,was observed for C:N *** values of C-and N-acquiring enzymes were higher at 0−5 cm in tropical dry forest areas and Angico forest,*** all land use types,the values of vectors L and A were higher than 1°and 45°,*** study showed that both land-use and soil depth influence the enzymatic stoichiometry,showing higher values of C-and N-acquiring enzymes in native and protected forests at soil surface.

关键词： C:N:P stoichiometry tropical forests soil depth Luvisols

Radiographic and tomographic description of marlin sucker Remora osteochir, Pisces: Echeneidae—preliminary data of one specimen

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Marine Life Science & Technology 2020年第3期2卷 246-251页

作者： AndréLuiz Veiga Conrado Renata Stecca lunes Carlos eduardo Malavasi Bruno Aline Tiemi Shiraishi Rocha JoséRoberto Machado Cunha da silva Laboratory of Evolutive Histophysiology Department of Cell and Developmental BiologyInstitute of Biomedical SciencesUniversity of Sao PauloAvenida ProfLineu Prestes1524Cidade UniversitariaSao Paulo 05508-000Brazil Laboratory of Immunological Techniques Applied to Morphophysiology School of Veterinary Medicine and Animal ScienceDepartment of SurgeryUniversity of Sao PauloAvenida Prof.Di.Orlando Marques de Paiva87.Cidade UniversitariaSao Paulo 05508-270Brazil

Remoras are commensal fish of various marine species,such as sharks,swordfishes,turtles,dolphins,manta rays and *** specimen of marlin sucker Remora osteochir was evaluated using computed tomography for skeletal digital reconstruction,digital radiology for general evaluation and bone counting,and the double contrast technique to distinguish coelomic *** radiographic images,it was possible to observe otoliths in the center of the neurocranium,to count 27 vertebrae,nine pairs of ribs,and to detect the presence of the hipural and epural bones near of the caudal *** double contrast images,it was possible to visualize the swim bladder,gills,heart,liver,stomach and *** the tomographic images and reconstructions,it was possible to identify the intercalar bones of the cephalic disc;the spine with vertebral bodies composed of neural arches and ventral ribs;and the pectoral girdle formed by posttemporal,cleithrum and scapulocoracoid *** was concluded that digital radiology and computed tomography were able to describe anatomical structures of marlin sucker *** without the need for dissection.

关键词： Teleost fish Double contrast Computed tomography Digital radiology Skeleton