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Earthquake Engineering and Engineering Vibration 2014年第4期13卷 583-597页

作者： Carlos S.Oliveira Gerard Gassol Xavier Goula teresa Susagna instituto superior técnico Universidade de Lisboa Institut Cartogràfic i Geològic de Catalunya

During the NERIES Project, an accelerometric database containing European digital information was developed. Besides event and station metadata, ground motion parameters, computed in a homogeneous manner, were assembled： PGA, PGV, AI, tD, Cav, H1 and PSV（f,5%）（19,961 components, 2629 events, 547 stations）. Merging small and moderate magnitude events produced a unique database capable of providing important information such as：（i） Correlations between several ground motion parameters follow analogous trends as in previous worldwide datasets, with slight corrections. （ii） Although PGA attenuations with distance show great uncertainties, four recent GMPEs recommended for Europe fit quite well the central 50% data interval for the distance range 10 〈 R 〈 200 kin; outside these distances, they do not fit. （iii） Soil amplification ratios indicate that weak motion （low magnitudes and larger distances） shows larger amplification than strong motion （short distances and large magnitudes） as represented in UBC97 for the USA, but not in EC8 for Europe. （iv） average spectral shapes are smaller than in the EC8. （v） Differences in amplification factors for PGA, PGV and HI for EC8 soil classes B and C, and differences in spectral shapes for these soil classes, indicate that EC8, type 2 S-coefficient should be frequency dependent, as in UBC97.

关键词： NERIES project parametric accelerometric database European region PGA EC8 soil amplification

Graphene electronic fibres with touch-sensing and lightemitting functionalities for smart textiles

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npj Flexible Electronics 2018年第1期2卷 231-236页

作者： Elias torres Alonso Daniela P.Rodrigues Mukond Khetani Dong-Wook Shin Adolfo De Sanctis Hugo Joulie Isabel de Schrijver Anna Baldycheva Helena Alves Ana I.S.Neves Saverio Russo Monica F.Craciun Centre for Graphene Science College of EngineeringMathematics and Physical SciencesUniversity of ExeterEX44QL ExeterUnited Kingdom Department of Physics and CICECO University of Aveiro3819-130 AveiroPortugal Centexbel Technologiepark-Zwijnaarde 79052 GhentBelgium Department of Physics Instituto Superior TécnicoUniversity of LisbonAv.Rovisco Pais 11040-001 LisbonPortugal

the true integration of electronics into textiles requires the fabrication of devices directly on the fibre itself using high-performance materials that allow seamless incorporation into *** electronics and opto-electronics,attained by intertwined fibres with complementary functions are the emerging and most ambitious technological and scientific *** we demonstrate graphene-enabled functional devices directly fabricated on textile fibres and attained by weaving graphene electronic fibres in a *** touch-sensors and light-emitting devices were produced using a roll-to-roll-compatible patterning technique,opening new avenues for woven textile ***,the demonstration of fabric-enabled pixels for displays and position sensitive functions is a gateway for novel electronic skin,wearable electronic and smart textile applications.

关键词： textiles smart functional

Investigating the physics of disruptions with real-time tomography at JEt

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Plasma Science and technology 2022年第3期24卷 80-88页

作者： Diogo R FERREIRA Pedro J CARVALHO Ivo S CARVALHO Chris I StUARt Peter J LOMAS JEt Contributors 无 instituto de Plasmas e Fusão Nuclear(IPFN) Instituto Superior Técnico(IST)Universidade de LisboaAv.Rovisco Pais 11049-001 LisboaPortugal Culham Centre for Fusion Energy(CCFE) UK Atomic Energy Authority(UKAEA)Culham Science CentreAbingdonOX143DB OxfordshireUnited Kingdom See the author list of E.Joffrin et al 2019 Nucl Fusion 59112021 EUROfusion Consortium JETCulham Science CentreAbingdonOX143DBUK

As JEt is developing and testing operational scenarios for higher fusion performance,an increase in pulse disruptivity is being *** a deeper analysis,we find that several radiative phenomena play an active role in determining the outcome of the *** analysis is enabled by the use of real-time tomography based on the bolometer *** though plasma tomography is an inverse problem,we use machine learning to train a forward model that provides the radiation profile directly,based on a single matrix multiplication *** model is used to investigate radiative phenomena including sawtooth crashes,ELMs and MARFE,and their relationship to the radiated power in different regions of *** particular,we use realtime tomography to monitor the core region,and to throw an alarm whenever core radiation exceeds a certain *** results suggest that this measure alone can anticipate a significant fraction of disruptions in the JEt baseline scenario.

关键词： plasma tomography machine learning plasma disruptions

Role of Kirkendall effect in diffusion processes in solids

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transactions of Nonferrous Metals Society of China 2014年第1期24卷 1-11页

作者： C.A.C.SEQUEIRA L.AMARAL Materials Electrochemistry Group ICEMSInstituto Superior TécnicoUniversidade de LisbonAvenida Rovisco Pais 11049-001 LisboaPortugal

In the 1940s, KIRKENDALL showed that diffusion in binary solid solutions cannot be described by only one diffusion coefficient. Rather, one has to consider the diffusivity of both species. His findings changed the treatment of diffusion data and the theory of diffusion itself. A diffusion-based framework was successfully employed to explain the behaviour of the Kirkendall plane. Nonetheless, the complexity of a multiphase diffusion zone and the morphological evolution during interdiffusion requires a physico-chemical approach. the interactions in binary and more complex systems are key issues from both the fundamental and technological points of view. this paper reviews the Kirkendall effect from the circumstances of its discovery to recent developments in its understanding, with broad applicability in materials science and engineering.

关键词： Kirkendall effect Kirkendall velocity Kirkendall planes diffusion couple technique solid-state diffusion interdiffusion

Fracture Loci in Sheet Metal Forming: A Review

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Acta Metallurgica Sinica(English Letters) 2015年第12期28卷 1415-1425页

作者： M.Beatriz Silva Kerim Isik A.Erman tekkaya Paulo A.F.Martins IDMEC Instituto Superior Técnico Universidade de Lisboa Institute of Forming technology and Lightweight Construction Technical University of Dortmund

Fracture in sheet metal forming usually occurs as ductile fracture, rarely as brittle fracture, at the operating temperatures and rates of loading that are typical of real processes in two different modes：（1） tensile and（2） in-plane shear（respectively, the same as modes I and II of fracture mechanics）. the circumstances under which each mode will occur are identified in terms of plastic flow and ductile damage by means of an analytical approach to characterize fracture loci under plane stress conditions that takes anisotropy into consideration. Fracture loci was characterized by means of the fracture forming limit line and by the shear fracture forming limit line in the fracture forming limit diagram. Experiments were performed with single point incremental forming and double-notched test specimens loaded in tension, torsion and in-plane shear give support to the presentation and allow determining the fracture loci of AA1050-H111 aluminium sheets with1 mm thickness. the relation between fracture toughness and the fracture forming limits was also investigated by comparing experimental values of the strains at fracture obtained from a truncated conical part produced by single point incremental forming and from double-notched test specimens loaded in tension.

关键词： Sheet forming Fracture Fracture forming limit diagram

Fatigue Reliability of Deck Structures Subjected to Correlated Crack Growth

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Journal of Marine Science and Application 2013年第4期12卷 413-421页

作者： G.Q.Feng Y.Garbatov C.Guedes Soares Centre for Marine technology and Engineering (CENtEC) Instituto Superior Técnico University of LisbonAv. Rovisco Pais

the objective of this work is to analyse fatigue reliability of deck structures subjected to correlated crack *** stress intensity factors of the correlated cracks are obtained by finite element analysis and based on which the geometry correction functions are *** Monte Carlo simulations are applied to predict the statistical descriptors of correlated cracks based on the Paris-Erdogan equation.A probabilistic model of crack growth as a function of time is used to analyse the fatigue reliability of deck structures accounting for the crack propagation correlation.A deck structure is modelled as a series system of stiffened panels,where a stiffened panel is regarded as a parallel system composed of plates and are *** has been proven that the method developed here can be conveniently applied to perform the fatigue reliability assessment of structures subjected to correlated crack growth.

关键词： crack growth fatigue reliability deck structures correlation stiffened panel

Modelling a Job-Shop Plant Using Queuing Networks techniques

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材料科学与工程（中英文B版） 2013年第9期3卷 612-618页

作者： Artur Barreiros Mechanical Engineering Department Instituto Superior T~cnico Av. Rovisco Pais 1049-O01Lisbon Portugal

this article illustrates the use of open queuing networks for the planning of discrete production systems of the job-shop type. For this purpose, it is assumed that the system can be modelled by a set of workstations. the mathematical and numerical procedures, related to the definition of the model that is used to characterize the system operations, are analyzed first. For this purpose, an ideal situation of a system with only two workstations and four products is used. Next, the application of the model to a real case study, corresponding to a metalworking company, is illustrated. In this case, the parameters that can be used to characterize the efficiency of the system are also introduced. the performance diagnostics involves the analysis of the work-in-process and the production lead-times. the optimization of the system involves the probabilistic characterization of the demand and the characterization of the probability of transference of products among workstations. Among other alternatives, a waiting-cost function, which is evaluated using the queuing parameters, can be used to compare alternative solutions.

关键词：排队网络作业车间网络技术建模生产系统厂房表征系统操作模型

Nonlocal material properties of single-walled carbon nanotubes

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International Journal of Smart and Nano Materials 2012年第2期3卷 141-151页

作者： J.V.Araújo dos Santos C.M.Mota Soares IDMEC Instituto Superior TécnicoUniversidade Técnica de Lisboa1049-001 LisboaPortugal

Natural frequencies of single-walled carbon nanotubes(SWCNts)obtained using a model based on Eringen’s nonlocal continuum mechanics and the timoshenko beam theory are compared with those obtained by molecular dynamics *** goal was to determine the values of the material constant,considered here as a nonlocal property,as a function of the length and the diameter of *** present approach has the advantage of eliminating the SWCNt thickness from the computations.A sensitivity analysis of natural frequencies to changes in the nonlocal material constant is also carried out and it shows that the influence of the nonlocal effects decreases with an increase in the SWCNt *** matching of natural frequencies shows that the nonlocal material constant varies with the natural frequency and the SWCNt length and diameter.

关键词： nonlocal mechanics molecular dynamics simulation single-walled carbon nanotube timoshenko beam

thermal lens analysis in a diode-pumped 10 Hz 100 mJ Yb:YAG amplifier

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High Power Laser Science and Engineering 2020年第2期8卷 24-31页

作者： Victor Hariton Celso Paiva Joao Hugo Pires Mario Galletti Goncalo Figueira GoLP/instituto de Plasmas e Fusao Nuclear Instituto Superior TécnicoUniversidade de LisboaAv.Rovisco Pais1049-001 LisbonPortugal Central Laser Facility Science and Technology Facilities CouncilRutherford Appleton LaboratoryHarwell Science and Innovation CampusDidcot OX110QXUK

We address the power scaling issue in end-pumped laser rod amplifiers by studying,experimentally and numerically,the magnitude of thermal lensing in a high-energy diode-pumped Yb:YAG *** spatio-temporal temperature profile of the gain medium and the focal length of the induced thermal lens are determined *** influence of the repetition rate and pumping power on the temperature distribution is *** measurements covered repetition rates between 1 and 10 Hz and up to 4 kW pumping power.

关键词： diode-pumped lasers high-energy laser amplifiers thermal effects in lasers ytterbium-doped laser media

Spudcan Penetration Simulation Using the Coupled Eulerian-Lagrangian Method with thermo-Mechanical Coupled Analysis

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Journal of Ocean University of China 2019年第2期18卷 317-327页

作者： YIN Qilin DONG Sheng JIANG Fengyuan GUEDES SOARES Carlos College of Engineering Ocean University of China Centre for Marine technology and Ocean Engineering (CENtEC) Instituto Superior Técnico

A novel modeling technique based on the coupled Eulerian-Lagrangian(CEL) method is provided to solve the geotechnical problems with large deformations. the technique is intended to solve the update problem of soil mechanical properties during spudcan penetration in normally consolidated clay soil. In the CEL model, the normal method of assigning an increasing shear strength profile with depth(NA) is defective due to its Eulerian framework. In this paper, a new technique is proposed to update soil material properties by introducing thermo-mechanical coupled analysis(tMCA) to the CEL models. During establishment of the CEL models, the optimal penetration velocity and minimum mesh size are determined through parametric studies. Reasonability and accuracy are then verified through comparison of the preliminary results with the soil flow configuration and penetration resistance(Fv) of a centrifuge test, and the results of the proposed method are compared with those of the remeshing and interpolation technique with small strain(RItSS) method. to achieve a CEL model with satisfactory accuracy, the NA and tMCA methods implemented in the CEL models and the RItSS method are first adopted in weightless soil. Comparison of the findings with those obtained in previous studies shows that the tMCA method can update material properties and predict Fv. the tMCA method is then applied to soils with self-weight and different shear strength profiles. Results show that the proposed method is capable of accurately modeling the large deformation problem of spudcan penetration in non-homogeneous clay.

关键词： thermo-mechanical coupled analysis non-homogeneous clay spudcan penetration CEL RItSS