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Formation and dispersal of rod-like α-SiAlON seed crystals synthesized by combustion method

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中国有色金属学会会刊：英文版 2005年第S3期15卷 439-442页

作者：傅仁利 j.m.F.ferreira 杨克涛陈克新 College of materials and Engineering Nanjing University of Aeroautics and Astroautics Nanjing 210016 China Department of Ceramics and Glass Engineering CICECO University of Aveiro 3810-193 Aveiro Portugal State Key Laboratory of New Ceramics and Fine Processing Tsinghua University Beijing 100084 China

Rod-like single-phase seed crystals of yttrium-α-SiAlONs were synthesized by combustion synthesis method. The XRD patterns, the morphologies of products and formation mechanism were investigated. The SEm observation of crystals exhibits well developed elongated hexagonal crystals with highly agglomerative features, assigned to pure and well-crystallized α-SiAlON. After special chemical treatments and water washing, the powders are well dispersed and still keep elongated hexagonal crystals, and the XRD pattern shows that the rod-like structure is crystalline yttrium-α-SiAlON with only a trace of β-SiAlON.

关键词： rod-like seed crystals Y-α-SiAlON combustion synthesis

The analysis of composite laminated beams using a 2D interpolating meshless technique

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Acta mechanica Sinica 2018年第1期34卷 99-116页

作者： S.H.m.Sadek j.Belinha m.P.L.Parente R.m.Natal jorge j.m.A.César de Sá A.j.m.ferreira Department of mechanical Engineering Faculty of EngineeringUniversity of Porto Institute of mechanical Engineering and Industrial management University of Porto

Laminated composite materials are widely implemented in several engineering constructions. For its relative light weight, these materials are suitable for aerospace, military, marine, and automotive structural applications. To obtain safe and economical structures, the modelling analysis accuracy is highly relevant. Since meshless methods in the recent years achieved a remarkable progress in computational mechanics, the present work uses one of the most flexible and stable interpolation meshless technique available in the literature—the Radial Point Interpolation method(RPIm).Here, a 2 D approach is considered to numerically analyse composite laminated beams. Both the meshless formulation and the equilibrium equations ruling the studied physical phenomenon are presented with detail. Several benchmark beam examples are studied and the results are compared with exact solutions available in the literature and the results obtained from a commercial finite element software. The results show the efficiency and accuracy of the proposed numeric technique.

关键词： Radial point interpolators RPIm Laminated beam meshless method

RPLP0/TBP are the most stable reference genes for human dental pulp stem cells under osteogenic differentiation

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World journal of Stem Cells 2024年第6期16卷 656-669页

作者： Daniel B ferreira Leticia m Gasparoni Cristiane F Bronzeri Katiucia B S Paiva Laboratory of Extracellular matrix Biology and Cellular Interaction Department of AnatomyInstitute of Biomedical SciencesUniversity of São PauloSão Paulo 05508-000São PauloBrazil

BACKGROUND Validation of the reference gene(RG)stability during experimental analyses is essential for correct quantitative real-time polymerase chain reaction(RT-qPCR)data ***,in an unreliable way,several studies use genes involved in essential cellular functions[glyceraldehyde-3-phosphate dehydro-genase(GAPDH),18S rRNA,andβ-actin]without paying attention to whether they are suitable for such experimental conditions or the reason for choosing such ***,such studies use only one gene when minimum Information for Publication of Quantitative Real-Time PCR Experiments guidelines recom-mend two or more *** impacts the credibility of these studies and causes dis-tortions in the gene expression *** tissue engineering,the accuracy of gene expression drives the best experimental or therapeutical *** cultivated DPSCs under two conditions:Undifferentiated and osteogenic dif-ferentiation,both for 35 *** evaluated the gene expression of 10 candidates for RGs[ribosomal protein,large,P0(RPLP0),TATA-binding protein(TBP),GAPDH,actin beta(ACTB),tubulin(TUB),aminolevulinic acid synthase 1(ALAS1),tyro-sine 3-monooxygenase/tryptophan 5-monooxygenase activation protein,zeta(YWHAZ),eukaryotic translational elongation factor 1 alpha(EF1a),succinate dehydrogenase complex,subunit A,flavoprotein(SDHA),and beta-2-micro-globulin(B2m)]every 7 d(1,7,14,21,28,and 35 d)by *** data were analysed by the four main algorithms,ΔCt method,geNorm,NormFinder,and BestKeeper and ranked by the RefFinder *** subdivided the samples into eight *** All of the data sets from clonogenic and osteogenic samples were analysed using the RefFinder *** final ranking showed RPLP0/TBP as the two most stable RGs and TUB/B2m as the two least stable *** theΔCt method or NormFinder analysis showed TBP/RPLP0 as the two most stable ***,geNorm analysis showed RPLP0/EF1αin the first *** algorithms’two least stab

关键词： Dental pulp stem cells Reference gene Housekeeping gene Endogenous gene Osteogenic differentiation RefFinder

A facile strategy for tuning the density of surface-grafted biomolecules for melt extrusion-based additive manufacturing applications

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Bio-Design and manufacturing 2024年第3期7卷 277-291页

作者： I.A.O.Beeren G.Dos Santos P.j.Dijkstra C.mota j.Bauer H.ferreira Rui L.Reis N.Neves S.Camarero-Espinosa m.B.Baker L.moroni Department of Complex Tissue Regeneration MERLN Institute for Technology-Inspired Regenerative MedicineMaastricht University6229 ER MaastrichtThe Netherlands 3B’s Research Group I3Bs–Research Institute on BiomaterialsBiodegradables and BiomimeticsHeadquarters of the European Institute of Excellence on Tissue Engineering and Regenerative MedicineUniversity of MinhoAveParkZona Industrial da Gandra4805-017 BarcoGuimarãesPortugal ICVS/3B’s-PT Government Associate Laboratory 4806-909 Braga/GuimarãesPortugal POLYmAT University of the Basque Country UPV/EHU20018 Donostia/San SebastiánSpain IKERBASQUE Basque Foundation for Science48009 BilbaoSpain

melt extrusion-based additive manufacturing(mE-Am)is a promising technique to fabricate porous scaffolds for tissue engi-neering ***,most synthetic semicrystalline polymers do not possess the intrinsic biological activity required to control cell *** of biomolecules on polymeric surfaces of Am scaffolds enhances the bioactivity of a construct;however,there are limited strategies available to control the surface ***,we report a strategy to tune the surface density of bioactive groups by blending a low molecular weight poly(ε-caprolactone)5k(PCL5k)containing orthogonally reactive azide groups with an unfunctionalized high molecular weight PCL75k at different *** porous three-dimensional(3D)scaf-folds were then fabricated using a high weight percentage(75 wt.%)of the low molecular weight PCL *** a proof-of-concept test,we prepared films of three different mass ratios of low and high molecular weight polymers with a thermopress and reacted with an alkynated fluorescent model compound on the surface,yielding a density of 201-561 pmol/cm^(2).Subsequently,a bone morphogenetic protein 2(BmP-2)-derived peptide was grafted onto the films comprising different blend compositions,and the effect of peptide surface density on the osteogenic differentiation of human mesenchymal stromal cells(hmSCs)was *** two weeks of culturing in a basic medium,cells expressed higher levels of BmP receptor II(BmPRII)on films with the conjugated *** addition,we found that alkaline phosphatase activity was only significantly enhanced on films contain-ing the highest peptide density(i.e.,561 pmol/cm^(2)),indicating the importance of the surface *** together,these results emphasize that the density of surface peptides on cell differentiation must be considered at the cell-material ***,we have presented a viable strategy for mE-Am community that desires to tune the bulk and surface functionality via blending of(m

关键词： Additive manufacturing Blending Surface functionalization Surface density Click chemistry Human

Independent and complementary bio-functional effects of CuO andGa_(2)O_(3) incorporated as therapeutic agents in silica-and phosphate-based bioactive glasses

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journal of materiomics 2022年第4期8卷 893-905页

作者： T.Tite A.C.Popa B.W.Stuart H.R.Fernandes I.m.Chirica G.A.Lungu D.macovei C.Bartha L.Albulescu C.Tanase S.Nita N.Rusu D.m.Grant j.m.F.ferreira G.E.Stan National Institute of materials Physics MagureleRO-077125Romania Advanced materials Research Group Faculty of EngineeringUniversity of NottinghamNG72RDUK CICECOdAveiro Institute of materials Department of Materials and Ceramics EngineeringUniversity of Aveiro3810-193AveiroPortugal “Victor Babes”National Institute of Research and Development in Pathology and Biomedical Sciences BucharestRO-050096Romania National Institute for Chemical Pharmaceutical Research and Development BucharestRO-031299Romania

The incorporation of therapeutic-capable ions into bioactive glasses(BGs),either based on silica(SBGs)or phosphate(PBGs),is currently envisaged as a proficient path for facilitating bone *** with this view,the single and complementary structural and bio-functional roles of CuO andGa_(2)O_(3)(in the 2e5 mol%range)were assessed,by deriving a series of SBG and PBG formulations startingfrom the parent glass systems,FastOs®BG e 38.5SiO2d36.1CaOd5.6P2O5d19.2mgOd0.6CaF2,and50.0P2O5d35.0CaOd10.0Na_(2)Od5.0 Fe2O_(3)(mol%),respectively,using the process of *** inter-linked physico-chemistry e biological response of BGs was assessed in search of bio-functional *** light was shed on the structural role e as network former or modifier e ofCu and Ga,immersed in SBG and PBG *** preliminary biological performance was surveyedin vitro by quantification of Cu and Ga ion release under homeostatic conditions,cytocompatibility assays(in fibroblast cell cultures)and antibacterial tests(against Staphylococcus aureus).The similar(Cu)anddissimilar(Ga)structural roles in the SBG and PBG vitreous networks governed their ***,Cuions were leached in similar concentrations(ranging from 10e35 ppm and 50e110 ppm at BG doses of 5and 50 mg/mL,respectively)for both type of BGs,while the release of Ga ions was 1e2 orders ofmagnitude lower in the case of SBGs(i.e.,0.2e6 ppm)compared to PBGs(i.e.,9e135 ppm).This wasattributed to the network modifier role of Cu in both types of BGs,and conversely,to the network former(SBGs)and network modifier(PBGs)roles of *** glasses were cytocompatible at a dose of 5 mg/mL,while at the same concentration the antimicrobial efficiency was found to be accentuated by the coupledrelease of Cu and Ga ions from *** collective assessment,the most prominent candidate material forthe further development of implant coatings and bone graft substitutes was delineated as the38.5SiO2d34.1CaOd5.6P2O5d16.2mgOd

关键词： Bioactive glass Copper Gallium Structure Ion release Antibacterial

Conversion of Rapid Prototyping models into metallic Tools by Ceramic moulding—an Indirect Rapid Tooling Process

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厦门大学学报(自然科学版) 2002年第S1期41卷 218-218页

作者： Teresa P DUARTE j m ferreira F jorge LINO A BARBEDO Rui NETO FEUP-Faculdade de Engenharia da Universidade do Porto DEMEGI-Departamento de Engenharia Mecanica e Gestāo IndustrialPortugal Departamento de Engenharia Cermica e do Vidro CICECOUniversidade de AveiroPortugal INEGI-Instituto de Engenharia mecanica e Gestāo Industrial CETECOFF-Fundicāo e Novas TecnologiasPortugal

A process to convert models made by rapid prototypi ng techniques like SL(stereolitography)and LOm(laminated object manufacturing)or by conventional techniques(silicones,resins,wax,etc.)into metallic mould s or tools has been *** main purpose of this technique is to rapidly obtain the first prototypes of parts,for plastics injection,forging or any oth er manufacturing process using the tools produced by casting a metal into a cera mic ***,it can be said that the ceramic moulds are produced by mixing in variab le proportions,depending on the type of ceramics employed,strength and roughne ss desired,a ceramic mixture composed by alumina and/or zirconium silicates bon ded with silica coming from a liquid binder,based on ethyl silicate.A catalyst is added to the slurry in order to produce a sol-gel *** liquid slur ry is poured into the box containing the mould to be *** a short p eriod of time,controlled by the amount of gelling agent,the ceramic mixture ac quires a rubber *** pattern is removed from the ceramic mould,whic h is fired to stop the gelation *** this stabilization the ceramic m ould is sintered at high temperatures in order to generate an inert mould wi th the desired strength in which almost all metallic alloys can be *** effect of ceramic materials(shape,granulometric distribution,chemical com position,etc.),processing parameters(proportion binder/ceramic/catalyst,sint ering conditions,etc.)and casting conditions(mould pre-heating temperature a nd pouring temperature)were studied in order to obtain metallic moulds or tools with tailored properties(high dimensional accuracy,low roughness and high mec hanical strength).

关键词： Conversion of Rapid Prototyping models into metallic Tools by Ceramic moulding an Indirect Rapid Tooling Process

Frequency-dependent viscoelasticity effects on the wave attenuation performance of multi-layered periodic foundations

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Applied mathematics and mechanics(English Edition) 2024年第3期45卷 407-424页

作者： m.SAFI m.VAKILIFARD m.j.mAHmOODI Faculty of Civil Water&Environmental EngineeringShahid Beheshti UniversityTehran ***Iran Faculty of mechanical and Energy Engineering Shahid Beheshti UniversityTehran ***Iran

In this paper,layered periodic foundations(LPFs)are numerically examined for their responses to longitudinal and transverse modes in the time and frequency *** different unit-cells,i.e.,2-layer,4-layer,and 6-layer unit-cells,comprising concrete/rubber,concrete/rubber/steel/rubber,and concrete/rubber/steel/rubber/lead/rubber materials,respectively,are taken into ***,the viscoelasticity behavior of the rubber is modeled with two factors,i.e.,a frequency-independent(FI)loss factor and a linear frequency-dependent(FD)loss *** the extraction of the complex dispersion curves and the identification of the band gaps(BGs),the simulations of wave transmission in the time and frequency domains are performed using the COmSOL *** parametric studies evaluate the effects of the rubber viscoelasticity models on the dispersion curves and the wave transmission for the longitudinal and transverse *** results show that considering the rubber viscoelasticity enhances the wave attenuation ***,the transverse-mode damping is more sensitive to the viscoelasticity model than its longitudinal *** 6-layer unit-cell LPF exhibits the lowest BG,ranging from 4.8 Hz to 6.5 Hz.

关键词： layered metamaterial periodic foundation complex dispersion curve wave transmission diagram

Selection of digital fabrication technique in the construction industry--A multi-criteria decision-making approach

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Frontiers of Structural and Civil Engineering 2024年第7期18卷 977-997页

作者： m.P.SALAImANImAGUDAm j.jAYAPRAKASH Department of Structural and Geotechnical Engineering School of Civil EngineeringVellore Institute of TechnologyVellore 632014India

Digital fabrication techniques,in recent decades,have provided the basis of a sustainable revolution in the construction ***,selecting the digital fabrication method in terms of manufacturability and functionality requirements is a complex *** paper presents alternatives and criteria for selection of digital fabrication techniques by adopting the multi-criteria decision-making *** alternatives considered in the study are concrete three-dimensional(3D)printing,shotcrete,smart dynamic casting,material intrusion,mesh molding,injection concrete 3D printing,and thin forming *** criteria include formwork utilization,reinforcement incorporation,geometrical complexity,material enhancement,assembly complexity,surface finish,and build *** demonstrates different multi-criteria decision-making techniques,with both subjective and objective weighting *** given ranking is based on the current condition of digital fabrication in the construction *** study reveals that in the selection of digital fabrication techniques,the criteria including reinforcement incorporation,build area,and geometrical complexity play a pivotal role,collectively accounting for nearly 70% of the overall *** the evaluated techniques,concrete 3D printing emerged as the best performer,however the shotcrete and mesh molding techniques in the second and third positions.

关键词： digital fabrication multicriteria decision-making concrete 3D printing

Lattice Boltzmann method formulation for simulation of thermal radiation effects on non-Newtonian Al_(2)O_(3) free convection in entropy determination

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Applied mathematics and mechanics(English Edition) 2024年第6期45卷 1085-1106页

作者： m.NEmATI m.SEFID A.KARImIPOUR A.j.CHAmKHA Faculty of mechanical Engineering Yazd UniversityYazd ***Iran Department of mechanical Engineering Najafabad BranchIslamic Azad UniversityNajafabad ***Iran Faculty of Engineering Kuwait College of Science and TechnologyDoha 35004Kuwait

The simultaneous investigation on the parameters affecting the flow of electrically conductive fluids such as volumetric radiation,heat absorption,heat generation,and magnetic field(mF)is very vital due to its existence in various sectors of industry and *** present research focuses on mathematical modeling to simulate the cooling of a hot component through power-law(PL)nanofluid convection *** temperature reduction of the hot component inside a two-dimensional(2D)inclined chamber with two different cold wall shapes is *** formulation of the problem is derived with the lattice Boltzmann method(LBm)by code writing via the FORTRAN *** variables such as the radiation parameter(0–1),the Hartmann number(0–75),the heat absorption/generation coefficient(−5–5),the fluid behavioral index(0.8–1.2),the Rayleigh number(103–105),the imposed mF angle(0°–90°),the chamber inclination angle(−90°–90°),and the cavity cold wall shape(smooth and curved)are *** findings indicate that the presence of radiation increases the mean Nusselt number value for the shear-thickening,Newtonian,and shear thinning fluids by about 6.2%,4%,and 2%,*** most cases,the presence of nanoparticles improves the heat transfer(HT)rate,especially in the cases where thermal conduction dominates *** is the lowest cooling performance index and mF effect for the cavity placed at an angle of 90°.The application in the design of electronic coolers and solar collectors is one of the practical cases of this numerical research.

关键词： thermal performance analysis heat absorption/generation power-law(PL)Al_(2)O_(3)nanofluid magnetohydrodynamics natural convection volumetric radiation inclined cavity