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Microstructure and properties of laser direct deposited CuNi17Al3Fe1.5Cr alloy

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International Journal of Minerals,Metallurgy and Materials 2011年第3期18卷 325-329页

作者： Yong-zhong Zhang Can Huang Rui Vilar Center for Composites General Research Institute for Non-ferrous Metals Beijing 100088 China Department of Materials Engineering and Institute of Materials and Surfaces Science and Engineering Instituto Superior Técnico 1049-001 Lisbon Portugal

thin walls of a copper-base alloy with the nominal composition CuNi17Al3Fe1.5Cr were successfully prepared by laser direct deposition additive manufacturing. the microstructure, as revealed by optical and scanning electron microscopy, indicated that the deposited material was fully dense and with a dendritic microstructure. the dendrites are parallel to the build-up direction, which is also the heat conduction direction during deposition. X-ray diffraction analysis results show that the deposited material is composed of a single phase and a copper-based solid solution. Some precipitate particles of metal silicides were observed in the interdendritic region by scanning electron microscopy. the ultimate tensile strength along the laser scanning direction reaches 735 MPa. the hardness is about Hv0.1 300.

关键词： copper alloys laser deposition microstructure mechanical properties

Characterization of the topography and Wettability of English Weed Leaves and Biomimetic Replicas

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Journal of Bionic Engineering 2014年第3期11卷 346-359页

作者： Pedro Miguel Matos Pereira Ana Sofia Moita Gabriel Amaro Monteiro Duarte Miguel Franca Prazeres IBB - Institute for Biotechnology and Bioengineering Centre for Biological and Chemical Engineering Department of Bioengineering Instituto Superior Tecnico Universidade de Lisboa Av. Rovisco Pals 1049-001 Lisboa Portugal IN+ - Center for Innovation Technology and Policy Research Instituto Superior T~cnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal

the topography and wettability of the underside of English weed （Oxalis pes-caprae） leaves and of their biomimetic replicas are investigated. Polyvinyl siloxane molds were cast from the leaves and then filled with an epoxy pre-polymer to produce replicas. the particular topographical structures of leaves and replicas were evaluated by optical microscopy and Scanning Electron Microscopy （SEM） analysis. the static wettability of leaves and replicas was assessed by contact angle measurements, while the dynamic wettability was characterized by estimating contact angle hysteresis and studying the dynamic behavior of impacting water droplets. A smooth glass slip and its replica were used as control surfaces. the replica moulding method used was able to transfer the characteristic pattern of irregular 100 μm - 200 μm × 60 μm convex papillae interspersed with stomata of the original leaf to the epoxy replicas. the static contact angle of 143°± 3° and the contact angle hysteresis of 2~ indicate that the underside of the English weed leaf is close to superhydrophobic. the lower contact angles （130° ± 4°） and higher hysteresis （31°） observed for the replica when compared with the original leaves were associated to an inaccurate replication of the chemistry and structures of the three-dimensional wax projections covering the plant surface. Also, trichomes in the original leaves could not be accurately reproduced due to their flexibility and fragility. Differences in wetting behavior were also evident from droplet impact experiments, with rebound regimes prevailing in the original leaves and regimes characterized by higher adhesion and larger dissipation predominating in the replicas. Nevertheless, the morphological features of the leaf transferred to the replica were sufficient to promote a clear hydrophobic behavior of the replica when compared with the smooth epoxy reference surface.

关键词： biomimetic surfaces oxalis pes-caprae English weed replica molding wettability micro-topography

Polyphenols as potential enhancers of stem cell therapy against neurodegeneration

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Neural Regeneration Research 2022年第10期17卷 2093-2101页

作者： Diana Rodríguez-Vera Antonio Abad-García Nancy Vargas-Mendoza Rodolfo Pinto-Almazán Eunice D.Farfán-García José A.Morales-González Marvin A.Soriano-Ursúa Sección de Estudios de Posgrado e Investigación.Escuela superior de Medicina Instituto Politécnico NacionalMéxico CityMéxico Unidad de Investigación Hospital Regional de Alta Especialidad IxtapalucaCarretera Federal México-Puebla km 34.5State of MéxicoMéxico

the potential of polyphenols for treating chronic-degenerative diseases(particularly neurodegenerative diseases)is ***,the selection of the best polyphenol for each treatment,the mechanisms by which they act,and their efficacy are frequently *** this review,the basics and the advances in the field,as well as suggestions for using natural and synthetic polyphenols alone or in a combinatorial strategy with stem cell assays,are compiled and ***,stem cells exhibit several responses when polyphenols are added to their environment,which could provide us with knowledge for advancing the elucidation of the origin of *** also,polyphenols are being included in the innovative strategies of novel therapies for treating neurodegenerative diseases as well as metabolic diseases related to *** this regard,flavonoid compounds are suggested as the best natural polyphenols due to their several mechanisms for acting in ameliorative effects;but increasing reports are involving other *** if some facts limiting bioactivity prevent them from conventional use,some natural polyphenols and derivatives hold the promise for being improved compounds,judged by their induced *** current results suggest polyphenols as enhancers of stem cell therapy against the targeted diseases.

关键词： Alzheimer’s disease chronic degenerative diseases combinatorial therapy metabolism neurodegenerative diseases neuronal damage neuroprotection Parkinson’s disease polyphenols stem cell assays

A Reference Model for the Analysis and Comparison of MDE Approaches for Web-Application Development

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Journal of Software Engineering and Applications 2010年第5期3卷 419-425页

作者： Jo&atilde o de Sousa Saraiva Alberto Rodrigues da Silva INESC-ID/instituto superior técnico Lisboa Portugal INESC-ID/instituto superior técnico Lisboa Portugal

the emerging Model-Driven Engineering (MDE) paradigm advocates the use of models as first-class citizens in the software development process, while artifacts such as documentation and source-code can be quickly produced from those models by using automated transformations. Even though many MDE-oriented approaches, languages and tools have been developed in the recent past, there is no standard that concretely defines a specific sequence of steps to obtain a functional software system from a model. thus, the existing approaches present numerous differences among themselves, because each one handles the problems inherent to software development in its own way. this paper presents and discusses a reference model for the comparative study of current MDE approaches in the scope of web-application development. this reference model focuses on relevant aspects such as modeling language scope (domain, business-logic, user-interface), usage of patterns, separation of concerns, model transformations, tool support, and deployment details like web-platform independence and traditional programming required. the ultimate goal of this paper is to determine the aspects that will be of greater importance in future web-oriented MDE languages.

关键词： Model-Driven Engineering Web Engineering Software Development

transparent conductive stannic oxide coatings employing an ultrasonic spray pyrolysis technique:the relevance of the molarity content in the aerosol solution for improvement the electrical properties

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Journal of Semiconductors 2022年第2期43卷 66-73页

作者： L.Castañeda Sección de Estudios de Posgrado e Investigación de la Escuela superior de Medicina Instituto Politécnico NacionalPlan de San Luis y Díaz Mirón s/nCasco de Santo TomásCiudad de MéxicoA.P.11340México

Highly transparent conductive stoichiometric nanocrystalline stannic oxide coatings were deposited onto Corning®EAGLE XG®slim glass *** each coating,it was deposited for various concentrations in the aerosol solution with the substrate temperature maintained at 623.15 K by an ultrasonic spray pyrolysis(USP)*** was em-ployed both as the solution carrier in addition to aerosol directing gas,maintaining its flow rates at 3500.0 and 500.0 mL/min,*** coatings were polycrystalline,with preferential growth along the stannic oxide(112)plane,irrespective of the molarity content in the spray *** coating prepared at 0.2 M,a concentration in the aerosol solution,showed an average transmission of 60%in the visible light region spectrum with a maximum conductivity of 24.86 S/*** coatings deposited exhibited in the general photoluminescence spectrum emission colors of green,greenish white,and bluish white calculated on the intensities of the excitonic and oxygen vacancy defect level emissions.

关键词： stannic oxide coatings ultrasonic spray pyrolysis

Liver disorders in COVID-19,nutritional approaches and the use of phytochemicals

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World Journal of Gastroenterology 2021年第34期27卷 5630-5665页

作者： Nancy Vargas-Mendoza Jazmín García-Machorro Marcelo Angeles-Valencia Marlet Martínez-Archundia Eduardo Osiris Madrigal-Santillán Ángel Morales-González Liliana Anguiano-Robledo JoséA Morales-González Laboratorio de Medicina de Conservacion Instituto Politécnico NacionalMéxico 11340Mexico Laboratorio de Diseño y Desarrollo de Nuevos Fármacos e Innovación Biotécnológica Instituto Politécnico NacionalMéxico 11340Mexico superior de Medicina Instituto Politécnico NacionalMéxico 11340Mexico Escuela superior de Cómputo Instituto Politécnico NacionalMéxico 07738Mexico Laboratorio de Farmacología Molecular Instituto Politécnico NacionalMéxico 11340Mexico Laboratorio Medicina de Conservación Escuela Superior de MedicinaInstituto Politécnico NacionalMéxico 11340Mexico

Coronavirus disease 2019(COVID-19),which is caused by severe acute respiratory syndrome-coronavirus-2(SARS-CoV-2),has affected millions of people *** was declared a pandemic by the World Health Organization in March *** hyperinflammatory response to the entry of SARS-CoV-2 into the host through angiotensin-converting enzyme 2 is the result of a“cytokine storm”and the high oxidative stress responsible for the associated *** only respiratory symptoms are reported,but gastrointestinal symptoms(diarrhea,vomiting,and nausea)and liver abnormalities(high levels of aspartate aminotransferase,alanine aminotransferase transaminases,and bilirubin)are observed in at least 30%of *** food intake and a delay in medical services may lead to malnutrition,which increases mortality and poor *** review provides some strategies to identify malnutrition and establishes nutritional approaches for the management of COVID-19 and liver injury,taking energy and nutrient requirements and their impact on the immune response into *** roles of certain phytochemicals in the prevention of the disease or as promising target drugs in the treatment of this disease are also considered.

关键词： COVID-19 Infection Liver Nutrition therapy Phytochemicals

A graph-based representation of knowledge for managing land administration data from distributed agencies–A case study of Colombia

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Geo-Spatial Information Science 2022年第2期25卷 259-277页

作者： Luis M.Vilches-Blázquez Jhonny Saavedra Investigación en Computación Instituto Politécnico NacionalMexico CityMexico School of Land Surveying Geodesy and Mapping EngineeringUniversidad Politécnica de MadridMadridSpain

Multiple efforts have been performed worldwide around diverse aspects of land ***,land administration data and systems’notorious heterogeneity remains a longstanding challenge to develop a harmonized *** this sense,the traditional Spatial Data Infrastructures adoption is not enough to overcome this challenge since data sources’heterogeneity implies needs related to harmonization interoperability,sharing,and integration in land administration *** paper proposes a graph-based represen-tation of knowledge for integrating multiple and heterogeneous data sources(tables,shape-files,geodatabases,and WFS services)belonging to two Colombian agencies within a decentralized land administration *** knowledge graphs are developed on an ontology-based knowledge representation using national and international standards for land *** approach aims to prevent data isolation,enable cross-datasets integration,accomplish machine-processable data,and facilitate the reuse and exploitation of multi-jurisdictional datasets in a single approach.A real case study demonstrates the applicability of the land administration data cycle deployed.

关键词： Land administration knowledge graph ontology heterogeneity data integration

Fatigue Reliability Assessment of Correlated Welded Web-frame Joints

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Journal of Marine Science and Application 2014年第1期13卷 23-31页

作者： W.Huang Y.Garbatov C.Guedes Soares Centre for Marine technology and Engineering (CENtEC) Instituto Superior Técnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portugal Centre for Marine technology and Engineering (CENtEC) Instituto Superior Técnico Universidade de Lisboa Av. Rovisco Pais 1049-001 Lisboa Portuga

the objective of this work is to analyze the fatigue reliability of complex welded structures composed of multiple web-frame joints, accounting for correlation effects. A three-dimensional finite element model using the 20-node solid elements is generated. A linear elastic finite element analysis was performed, hotspot stresses in a web-frame joint were analyzed and fatigue damage was quantified employing the S-N approach. the statistical descriptors of the fatigue life of a non-correlated web-frame joint containing several critical hotspots were estimated. the fatigue reliability of a web-frame joint wasmodeled as a series system of correlated components using the Ditlevsen bounds. the fatigue reliability of the entire welded structure with multiple web-frame joints, modeled as a parallel system of non-correlated web-frame joints was also calculated.

关键词： Keywords fatigue reliability hotspot stress S-N approach finiteelement analysis web-frame joints

Analysis of foundation sliding of an arch dam considering the hydromechanical behavior

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Frontiers of Structural and Civil Engineering 2012年第1期6卷 35-43页

作者： Maria Luísa Braga FARINHA JoséVieira de LEMOS Emanuel MARANHA DAS NEVES LNEC-National Laboratory for Civil Engineering Av.Brasil 101Lisboa 1700-066Portugal ist-instituto superior técnico Av.Rovisco Pais 1Lisboa 1049-001Portugal

this paper presents the application of a methodology which can be used to assess arch dam foundation stability,using the discrete element method(DEM)and the code 3DEC.A global three-dimensional model of a dam foundation was developed,in which some discontinuities were simulated and both the grout and drainage curtains were *** model,calibrated taking into account recorded data,was used to carry out nonlinear mechanical *** same model was employed to perform a hydraulic analysis,based on equivalent continuum concepts,which allowed the water pressure pattern within the foundation to be *** water pressures were applied on discontinuities involved in the possible sliding mechanism along the dam/foundation interface,and the safety of the dam/foundation system was evaluated using a process of reduction of strength characteristics,with the aim of calculating the minimum safety factors that ensure *** were compared with those obtained with the usual bi-linear uplift pressure distribution at the base of the dam,commonly used in concrete dam *** relevance of carrying out hydraulic analysis in arch dam foundation failure studies is highlighted.

关键词： concrete dams rock foundations hydromechanical behavior failure analysis