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Analysis of a passive ankle exoskeleton for reduction of metabolic costs during walking

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Defence Technology（防务技术） 2024年第7期37卷 62-68页

作者： Luís Quinto Pedro Pinheiro sergio B.Goncalves ivo Roupa Paula simoes Miguel Tavares da silva CINAMIL Academia MilitarInstituto Universitario MilitarLisbonPortugal IDMEC Instituto Superior TecnicoUniversidade de LisboaLisbonPortugal

Modern conflicts demand substantial physical and psychological exertion,often resulting in fatigue and diminished combat or operational *** exoskeletons have been developed recently to address these challenges,presenting various limitations that affect their operational or everyday *** article evaluates the performance of a dual-purpose passive ankle exoskeleton developed for the reduction of metabolic costs during walking,seeking to identify a force element that could be applied to the target *** on the 6-min walk test,twenty-nine subjects participated in the study using three different force *** results indicate that it is possible to reduce metabolic expenditure while using the developed ***,the comfort and range of motion results verify the exoskeleton's suitability for use in uneven terrain and during extended ***,the choice of the force element should be tailored to each user,and the control system should be adjustable to optimise the exoskeleton's performance.

关键词： Ankle passive exoskeleton Metabolic cost reduction Dual-use exoskeleton Gait Biomechanics

Anomalies in the short-range local environment and atomic diffusion in single crystalline equiatomic CrMnFeCoNi highentropy alloy

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Nano Research 2024年第6期17卷 5336-5348页

作者： Alevtina smekhova Daniel Gaertner Alexei Kuzmin Ana Guilherme Buzanich Goetz schuck ivo Zizak Gerhard Wilde Kirill V.Yusenko sergiy Divinski Helmholtz-Zentrum Berlin für Materialien und Energie(HZB) D-12489 BerlinGermany Institute of Materials Physics University of MünsterD-48149 MünsterGermany Institute of solid state Physics University of LatviaLV-1063 RigaLatvia Bundesanstalt für Materialforschung und–prüfung(BAM) D-12489 BerlinGermany

Multi-edge extended X-ray absorption fine structure(EXAFs)spectroscopy combined with reverse Monte Carlo(RMC)simulations was used to probe the details of element-specific local coordinations and component-dependent structure relaxations in single crystalline equiatomic CrMnFeCoNi high-entropy alloy as a function of the annealing *** representative states,namely a high-temperature state,created by annealing at 1373 K,and a low-temperature state,produced by long-term annealing at 993 K,were compared in *** features identified in atomic configurations of particular principal components indicate variations in the local environment distortions connected to different degrees of compositional disorder at the chosen representative *** detected changes provide new atomistic insights and correlate with the existence of kinks previously observed in the Arrhenius dependencies of component diffusion rates in the CrMnFeCoNi high-entropy alloy.

关键词： high-entropy alloys diffusion short-range order extended X-ray absorption fine structure(EXAFs) reverse Monte Carlo

Bogomolov Multipliers for some p-groups of Nilpotency Class 2

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Acta Mathematica sinica,English series 2016年第5期32卷 541-552页

作者： ivo MICHAILOV Faculty of Mathematics and Informatics Shumen University "Episkop Konstantin Preslavski"

The Bogomolov multiplier B0 （G） of a finite group G is defined as the subgroup of the schur multiplier consisting of the cohomology classes vanishing after restriction to all abelian subgroups of G. The triviality of the Bogomolov multiplier is an obstruction to Noether＇s problem. We show that if G is a central product of G1 and G2, regarding Ki ≤ Z（Gi）,i = 1,2, and θ ： G1 →G2 is a group homomorphism such that its restriction θ｜K1 ： K1 → K2 is an isomorphism, then the triviality of Bo（G1/K1）, Bo（G1） and B0（G2） implies the triviality of Bo（G）. We give a positive answer to Noether＇s problem for all 2-generator p-groups of nilpotency class 2, and for one series of 4-generator p-groups of nilpotency class 2 （with the usual requirement for the roots of unity）.

关键词： Bogomolov multiplier Noether's problem rationality problem central product of groups p-groups of nilpotency class 2

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

Unravelling the protracted U-Pb zircon geochronological record of high to ultrahigh temperature metamorphic rocks:Implications for provenance investigations

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Geoscience Frontiers 2023年第2期14卷 116-132页

作者： Mahyra Tedeschi Pedro Leonardo Rossi Vieira Matheus Kuchenbecker Bruno VRibeiro Vitor Barrote Humberto Reis Laura stutenbecker Cristiano Lana Antonio Pedrosa-soares ivo Dussin Programa de Pós-graduação em Geologia da Universidade Federal de Minerais Centro de Pesquisas Manoel Teixeira da CostaInstitute of GeosciencesFederal University of Minas GeraisAv.Antônio Carlos6627Belo Horizonte 31270-901Brazil Institute of Geological sciences University of Bern3012 BernSwitzerland Laboratório de Estudos Tectônicos Universidade Federal dos Vales do Jequitinhonha e MucuriRodovia MGT 367Km 583-Diamantina 39100-000Brazil school of Earth Atmosphere and EnvironmentMonash UniversityClaytonVictoria 3800Australia Timescales of Mineral systems Group School of Earth and Planetary SciencesCurtin UniversityPerthWA 6845Australia Freie Universität Berlin Institut für Geologische WissenschaftenGeochemieMalteserstr.1074-10012249 BerlinGermany Departamento de Geologia-Escola de Minas Universidade Federal de Ouro Preto 35400-000Brazil Department of Materials and Earth sciences Institute of Applied GeosciencesTU DarmstadtSchnittspahnstr.964287 DarmstadtGermany TEKTOs Geotectonic Research Group Geology InstituteRio de Janeiro State UniversitySão Francisco Xavier Street524/4030-AMaracanãRio de Janeiro 20550-900Brazil

The assessment of detrital zircon age records is a key method in basin analysis,but it is prone to several biases that may compromise accurate sedimentary provenance *** to ultrahigh temperature(HT-UHT)metamorphism(especially if T>850℃)is herein presented as a natural cause of bias in provenance studies based on U-Pb detrital zircon ages,since zircon from rocks submitted to these extreme and often prolonged conditions frequently yield protracted,apparently concordant,geochronological *** age spreading can result from disturbance of the primary U-Pb zircon system,likewise from(re)crystallization processes during multiple and/or prolonged metamorphic *** this contribution,available geochronological data on Archean,Neoproterozoic and Palaeozoic HT-UHT metamorphic rocks,acquired by different techniques(sIMs and LA-ICP-Ms)and showing distinct compositions,are reassessed to demonstrate HT-UHT metamorphism may result in modes and age distributions of unclear geological *** a consequence,it may induce misinterpretations on UPb detrital zircon provenance analyses,particularly in sedimentary rocks metamorphosed under such extreme temperature *** evaluate the presence of HT-UHT metamorphism-related bias in the detrital zircon record,we suggest a workflow for data acquisition and interpretation,combining a multi-proxy approach with:(i)in situ U-Pb dating coupled with Hf analyses to retrieve the isotopic composition of the sources,and(ii)the integration of a petrochronological investigation to typify fingerprints of the HT-UHT metamorphic *** proposed workflow is validated in the investigation of one theoretical and one natural example allowing a better characterization of the sedimentary sources,maximum depositional ages,and the tectonic setting of the *** workflow allows to the appraisal of biases imposed by HT-UHT metamorphism and resulting disturbances in the U-Pb detrital zircon record,particularly for sedimentary

关键词： Detrital zircon Protracted zircon record sedimentary basins UHT metamorphism Prolonged metamorphism Bias in detrital zircon

An Endogenous Feedback and Entropy Analysis in Machine Learning Model for stock’s Return Forecast

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Intelligent Automation & soft Computing 2023年第6期36卷 3175-3190页

作者： Edson Vinicius Pontes Bastos Jorge Junio Moreira Antunes Lino Guimaraes Marujo Peter Fernandes Wanke Roberto ivo da Rocha Lima Filho Instituto Alberto Luiz Coimbra de Pos-Graduação e Pesquisa de Engenharia-COPPE Universidade Federal do Rio de Janeiro(UFRJ)Rio de Janeiro21941-598Brasil Instituto de Pos-Graduacao em Administracao-Coppead Universidade Federal do Rio de Janeiro(UFRJ)21941-918Brasil

stock markets exhibit Brownian movement with random,non-linear,uncertain,evolutionary,non-parametric,nebulous,chaotic characteristics and dynamism with a high degree of *** an algorithm to predict returns for decision-making is a challenging *** addition,the choice of vari-ables that will serve as input to the model represents a non-triviality,since it is possible to observe endogeneity problems between the predictor and the predicted ***,the goal is to analyze the endogenous origin of the stock return prediction model based on technical *** this,we structure a feed-for-ward neural *** evaluate the endogenous feedback between the pre-dicted returns and technical analysis indicators based on the generated *** is possible to predict the *** high accuracy of the model indicates that,during the test period,there is a hit rate close to 76%.Regarding endogeneity,the term of interest and the return are the variables that influence the largest number of *** results will help investors build investment strategies based on this expert system applied to forecasting.

关键词： Forecast endogeneity neural networks differential evolution stochastic optimization

Rhyacian-Orosirian tectonic history of the Juiz de Fora Complex:Evidence for an Archean crustal reservoir within an island-arc system

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Geoscience Frontiers 2022年第5期13卷 350-369页

作者： Rasec Almeida Vitalino Elizeu Henrique Bruno samuel Moreira Bersan Lucas Eduardo de Abreu Barbosa Araujo ivo Dussin Claudio de Morisson Valeriano Carla Neto Monica Heilbron Universidade do Estado do Rio de Janeiro Faculdade de GeologiaTektos–Grupo de Pesquisa em GeotectônicaRua São Francisco Xavier 524MaracanãRio de JaneiroBrazil Laboratório de Geocronologia e Isótopos Radiogênicos Universidade do Estado do Rio de JaneiroRua São Francisco Xavier 524MaracanãRio de JaneiroBrazil

The southern são Francisco Paleocontinent(sFP)comprises Archean nuclei and Paleoproterozoic complexes encompassing magmatic arcs juxtaposed during a Rhyacian to Orosirian orogenic *** Juiz de Fora Complex(JFC)represents an imbricated thrust system that comprises orthogranulites with a wide compositional range formed in an intra-oceanic setting during the siderian to the Orosirian and later accreted to the southeastern margin of the *** we report new petrological,geochemical,whole-rock Nd and sr data,as well as zircon U–Pb ages from felsic and mafic orthogranulites from the *** new data is combined with a regional compilation that enables an evaluation of the interaction between magmatism and orogenetic episodes in the context of the consolidation of são Francisco Paleocontinent during the Rhyacian–*** collisional Island Arc tholeiites(IAT),Tonalites-Tron dhjemites-Granodiorites(TTGs)and sanukitoid magmatism occurred from 2200 Ma to 2085 *** was followed by post-collisional magmatism,which is represented by hybrid granitoids coeval with the emplacement of E-MORB basic *** signatures for the Rhyacian to Orosirian evolution are highlighted by the dominance of negativeεNd(t)associated with Meso-to Neoarchean Nd TDMmodel ages as well as inherited zircon grains from the hybrid *** JFC is extensively highlighted in the literature as a primitive intra-oceanic arc,but here we propose the reworking or recycling of ancient crustal segments within the mature arc stage of the JFC,suggesting a Mesoarchean crustal source involved in the JFC evolution.

关键词： Juiz de Fora complex Paleoproterozoic magmatic arc TTG and sanukitoid são Francisco Paleocontinent

Adaptive hp-FEM with Arbitrary-Level Hanging Nodes for Maxwell’s Equations

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Advances in Applied Mathematics and Mechanics 2010年第4期2卷 518-532页

作者： Pavel solin Lenka Dubcova ivo Dolezel Department of Mathematics and statistics University of NevadaReno89557USA Institute of Thermomechanics Academy of Sciences of the Czech RepublicNarodni 311720 Praha 1Czech Republic

Adaptive higher-order finite element methods(hp-FEM)are well known for their potential of exceptionally fast(exponential)***,most hp-FEM codes remain in an academic setting due to an extreme algorithmic complexity of hp-adaptivity *** paper aims at simplifying hpadaptivity for H(curl)-conforming approximations by presenting a novel technique of arbitrary-level hanging *** technique is described and it is demonstrated numerically that it makes adaptive hp-FEM more efficient compared to hp-FEM on regular meshes and meshes with one-level hanging nodes.

关键词： hp-FEM arbitrary-level hanging nodes irregular meshes higher-order edge elements Maxwell’s equations

Evaluation of soil Quality Indicators in sugarcane Management in sandy Loam soil

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Pedosphere 2009年第3期19卷 312-322页

作者： s.A.C.sANT'ANNA M.F.FERNANDEs W.M.P.M.ivo J.L.s.COsTA Brazilian Agricultural Research Corporation (Embrapa Coastal Tablelands) Av. Beira Mar 3250 Aracaju SE 49025- 040 (Brazil) Departament of Physiology Universidade Federal de Sergipe So Cristóvo SE 49100-000 (Brazil) Brazilian Agricultural Research Corporation (Embrapa Coastal Tablelands) Av. Beira Mar 3250 Aracaju SE 49025-040 (Brazil) Brazilian Agricultural Research Corporation (Embrapa) Brasília DF 70770-901 (Brazil)

An important factor for the sustainability of soils highly susceptible to degradation is the use of monitoring tools that promptly and realistically reflect changes imposed on soil by different cropping systems. To select soil quality indicator variables in sugarcane (saccharum officinarum L.) production areas that fulfill the criteria of sensitivity to management practices and between-season consistency in the management discrimination, ten composite soil samples (0–10 cm) were collected in July 2005 (rainy season) and again in March 2006 (dry season) from areas under cultivation of organic sugarcane (Os), green sugarcane (Gs), burned sugarcane (Bs) and from an adjacent native forest (NF) area at Usina Triunfo, Boca da Mata, Alagoas, Brazil. Microbial biomass-C (MBC), total organic C (TOC), soil enzyme activity expressed as the rate of fluorescein diacetate (FDA) hydrolysis, mean weight diameter of water-stable soil aggregates (MWD), and percentage of water-stable macroaggregates (PWsA) were analyzed. Although MBC and TOC were higher in NF than in the cultivated areas, no differences were observed in these C pools between the three sugarcane systems. The response of FDA to the site management was dependent on the sampling time. In the rainy period, the activity followed the order: NF > Os > Gs > Bs, whereas in the dry season, only NF differed from the other treatments. Irrespective of the sampling time, MWD and PWsA decreased in the order NF > Os = Gs > Bs. The variables MWD and PWsA are quite sensitive for discriminating between site management histories regardless the sampling season.

关键词：土壤耕作制度一致性管理质量评价指标甘蔗沙壤土核转录因子微生物生物量碳美国FDA