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ON THE UNIQUENESS OF THE WEAK SOLUTIONS OF A QUASILINEAR HYPERBOLIC SYSTEM WITH A SINGULAR SOURCE TERM

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Chinese Annals of Mathematics,Series B 2002年第3期23卷 317-324页

作者： j.P.dias M.FIGUEIRA Dedicated to the memory of jacques-Louis Lions Dedicated to the memory of Jacques-Louis Lions

This paper is a continuation of the authors' previous paper [1]. In this paper the authors prove, assuming additional conditions on the initial data, some results about the existence and uniqueness of the entropy weak... 详细信息

关键词： Cauchy problem Weak solution Quasilinear hyperbolic system

Thermal manipulation of plasmons in atomically thin films

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Light(Science & Applications) 2020年第1期9卷 1179-1189页

作者： Eduardo j.C.dias Renwen Yu F.javier Garcia de Abajo ICFO-Institut de Ciencies Fotoniques The Barcelona Institute of Science and Technology08860 Castelldefels(Barcelona)Spain ICREA-Institucio Catalana de Recerca i Estudis Avançats Passeig Lluis Companys 2308010 BarcelonaSpain

Nanoscale photothermal effects enable important applications in cancer therapy,imaging and *** effects also induce substantial changes in the optical response experienced by the probing light,thus suggesting their application in all-optical ***,we demonstrate the ability of graphene,thin metal films,and graphene/metal hybrid systems to undergo photothermal optical modulation with depths as large as>70%over a wide spectral range extending from the visible to the terahertz frequency *** envision the use of ultrafast pump laser pulses to raise the electron temperature of graphene during a picosecond timescale in which its mid-infrared plasmon resonances undergo dramatic shifts and broadenings,while visible and near-infrared plasmons in the neighboring metal films are severely attenuated by the presence of hot graphene *** study opens a promising avenue toward the active photothermal manipulation of the optical response in atomically thin materials with potential applications in ultrafast light modulation.

关键词： pump visible films

The radiative decay D^(0)→ K^(*0)γ with vector meson dominance

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Chinese Physics C 2018年第4期42卷 135-141页

作者： j. M. dias V. R. Debastiani ju-jun Xie E. Oset Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China Departamento de Física Teórica and IFIC Centro Mixto Universidad de Valencia-CSIC Institutos de Investigación de Paterna Aptdo. 22085 46071 Valencia Spain Instituto de Física Universidade de S？o Paulo C. P. 66318 05389-970 S？o Paulo SP Brazil

Motivated by the experimental measurements of D0 radiative decay modes, we have proposed a model to study the D0→ K＊0γ decay, by establishing a link with D0→ K＊0V （V=ρ0, ω） decays through the vector meson dominance hypothesis. In order to do this properly, we have used the Lagrangians from the local hidden gauge symmetry approach to account for Vγ conversion. As a result, we have found the branching ratio B[D0→ K＊0γ]=（1.55-3.44）×10-4, which is in fair agreement with the experimental values reported by the Belle and BaBar collaborations.

关键词： radiative decay vector meson dominance local hidden gauge symmetry

Thermal and structural properties of Nd2O3-doped calcium boroaluminate glasses

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journal of Rare Earths 2016年第5期34卷 521-528页

作者： j.D.M.dias G.H.A.Melo T.A.Lodi j.O.Carvalho P.F.Facanha Filho M.j.Barboza A.Steimacher F.Pedrochi Centro de Ciencias Sociais Saude e TecnologiaUniversidade Federal do Maranhao-Imperatriz MA Instituto Federal de Educaceo Ciencia e Tecnologia do Maranhao Campus Imperatriz-Imperatriz-MA Instituto Federal de Educacao Ciencia e Tecnologia do Tocantins Campus Araguaina-Araguaina-TO

Nd^3＋ doped CaO-Al2O-B2O3-CaF2 glasses were prepared by conventional melt-quenching technique,and their structural and thermal properties were *** amorphous nature of these samples was confirmed by X-ray diffraction（XRD）.The measured density showed an increase with Nd2O3 doping,at the expense of *** spectra presented changes with addition of Nd2O3,which indicated that the network structure of the glasses studied presented various borate groups,such as tetraborates,metaborates,ortho-borates and pyroborates *** N4 values calculated from FTIR spectra revealed that incorporation of Nd2O3 into glass network converted the structural units from BO4 to *** the analysis of DTA curves,we verified that Tg increased with the addition of Nd2O3;it was similar to the behavior caused by modifier oxides in the structure of borate *** that,the calculated glass stability Tx–Tg for doped samples presented a decrease if compared to the undoped *** heat and thermal conductivity did not present significant changes with Nd2O3 concentration,up to 2.30 mol.%.The results of density,DTA,Raman and FTIR reinforced the idea that Nd2O3 acted as network modifier.

关键词： Nd^3+ Nd^3+ doped glass borate glasses glass structure thermal properties rare earths

Ξbb and Ωbbb molecular states

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Chinese Physics C 2020年第6期44卷 87-94页

作者： j.M.dias Qi-Xin Yu Wei-Hong Liang Zhi-Feng Sun ju-jun Xie E.Oset m.dias1 2qi-xin yu13wei-hong liang14zhi-feng sun5ju-jun xie6785.oset191.department of physicsguangxi normal universityguilin 541004china instituto de física universidade de são paulorua do matão 1371.butantãcep 05508-090são paulosão paulobrazil institute for experimental physics department of physicsuniversity of hamburgluruper chaussee 149d-22761 hamburggermany guangxi key laboratory of nuclear physics and technology guangxi normal universityguilin 541004china school of physical science and technology lanzhou universitylanzhou 730000china institute of modern physics chinese academy of scienceslanzhou 730000china school of physics and microelectronics zhengzhou universityzhengzhou 450001china school of nuclear science and technology university of chinese academy of sciencesbeijing 100049china departamento de física teórica and ific centro mixto universidad de valencia-csic institutos de investigación de paternaaptdo.2208546071 valenciaspain

Using the vector exchange interaction in the local hidden gauge approach,which in the light quark sector generates the chiral Lagrangians and has produced realistic results for Ωc,Ξc,Ξb and the hidden charm pentaquark states,we study the meson-baryon interactions in the coupled channels that lead to the Ξbb and Ωbbb excited states of the molecular *** obtain seven states of the Ξbb type with energies between 10408 and 10869 MeV,and one Ωbbb state at 15212 MeV.

关键词： doubly-heavy baryons strong interaction molecular state

A Quasilinear System Related with the Asymptotic Equation of the Nematic Liquid Crystal’s Director Field

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Chinese Annals of Mathematics,Series B 2021年第2期42卷 163-172页

作者： joão-Paulo dias Departamento de Matemática and CMAFcIO Faculdade de Ciências da Universidade de LisboaCampo GrandeEdificio C61749-016 LisboaPortugal

In this paper, the author studies the local existence of strong solutions and their possible blow-up in time for a quasilinear system describing the interaction of a short wave induced by an electron field with a long wave representing an extension of the motion of the director field in a nematic liquid crystal’s asymptotic model introduced in[Saxton, R. A., Dynamic instability of the liquid crystal director. In: Current Progress in Hyperbolic Systems(Lindquist, W. B., ed.), Contemp. Math., Vol.100, Amer. ***., Providence, RI, 1989, pp.325–330] and [Hunter, j. K. and Saxton, R. A., Dynamics of director fields, SIAM j. Appl. Math., 51, 1991, 1498–1521] and studied in [Hunter, j. *** Zheng, Y., On a nonlinear hyperbolic variational equation I, Arch. Rat. Mech. Anal.,129, 1995, 305–353], [Hunter, j. K. and Zheng, Y., On a nonlinear hyperbolic variational equation II, Arch. Rat. Mech. Anal., 129, 1995, 355–383] and in [Zhang, P. and Zheng,Y., On oscillation of an asymptotic equation of a nonlinear variational wave equation,Asymptotic Anal., 18, 1998, 307–327] and, more recently, in [Bressan, A., Zhang, P. and Zheng, Y., Asymptotic variational wave equations, Arch. Rat. Mech. Anal., 183, 2007,163–185].

关键词： Benney system Conservation law Schrödinger equation Nematic liquid crystal Director field

Modeling Size-number Distributions of Seeds for Use in Soil Bank Studies

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journal of Integrative Plant Biology 2008年第5期50卷 531-535页

作者： Hugo Casco Alexandra Soveral dias Luís Silva dias Chemical Ecology Unit Centre of Ecology and EnvironmentUniversidade de vora7002-554 vora Portugal

Knowledge of soil seed banks is essential to understand the dynamics of plant populations and communities and would greatly benefit from the integration of existing knowledge on ecological correlations of seed size and shape. The present study aims to establish a feasible and meaningful method to describe size-number distributions of seeds in multi-species situations. For that purpose, size-number distributions of seeds with known length, width and thickness were determined by sequential sieving. The most appropriate combination of sieves and seeds dimensions was established, and the adequacy of the power function and the Weibull model to describe size-number distributions of spherical, non-spherical, and all seeds was investigated. We found that the geometric mean of seed length, width and thickness was the most adequate size estimator, providing shape-independent measures of seeds volume directly related to sieves mesh side, and that both the power function and the Weibull model provide high quality descriptions of size-number distributions of spherical, non-spherical, and all seeds. We also found that, in spite of its slightly lower accuracy, the power function is, at this stage, a more trustworthy model to characterize size-number distributions of seeds in soil banks because in some Weibull equations the estimates of the scale parameter were not acceptable.

关键词： accuracy power function seeds shape seeds size size-number distributions Weibull model.

Numerical study on the use of soft material walls to enhance seismic performance of an existing tunnel

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Underground Space 2024年第2期15卷 90-112页

作者： Qiangqiang Sun Menghao Hou Daniel dias Institute of Geotechnical Engineering College of Civil Engineering and ArchitectureHebei UniversityBaoding 071002China Laboratory 3SR CNRS UMR 5521Grenoble Alpes UniversityGrenoble 38000France

Seismic risk is one of the biggest challenges for tunnel safety,and several mitigation techniques have been proposed to enhance the seismic performance of existing *** paper aims to investigate the effectiveness of an innovative approach for reducing the seismic risk of existing tunnels by using soft material walls(SMW)symmetrically installed in the surrounding *** investigation is performed with a two-dimensional numerical model and the effectiveness of SMW in mitigating the seismic-induced lining forces is quantitatively evaluated by reduction *** influences of nonlinear properties of soil,SMW and tunnel lining on the isolation effectiveness are also *** parametric studies show that the computed reduction ratio is strongly affected by the modulus ratio between the SMW and the soil,the wall geometric parameter,and the flexibility *** is more effective for the thick and soft isolation walls that are inserted near a stiff tunnel in the soft *** tunnel seismic response can be reduced by up to 50%for the scenarios ***,the parametric study identifies an optimum normalized depth of SMW and recommends a relation between the maximum isolation effect and the flexibility ***,simple charts are suggested in this work for estimating the isolation effect in specific conditions of the soil and the *** these lines,the results of this work may be used in the seismic retrofitting of an existing tunnel,aiding the preliminary design of the isolation walls.

关键词： Tunnels Earthquakes Seismic analysis Isolation walls Soft material

Utilizing semantic-level computer vision for fracture trace characterization of hard rock pillars in underground space

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Geoscience Frontiers 2024年第2期15卷 366-391页

作者： Chuanqi Li jian Zhou Daniel dias Laboratory 3SR CNRS UMR 5521Grenoble Alpes UniversityGrenoble 38000France School of Resources and Safety Engineering Central South UniversityChangsha 410083China

This study utilizes a semantic-level computer vision-based detection to characterize fracture traces of hard rock pillars in underground *** trace images captured by photogrammetry are used to establish the database for training two convolutional neural network(CNN)-based models,i.e.,U-Net(University of Freiburg,Germany)and DeepLabV3+(Google,USA)*** code technology,polyline approximation algorithm,and the circular window scanning approach are combined to quantify the main characteristics of fracture traces on flat and uneven surfaces,including trace length,dip angle,density,and *** extraction results indicate that the CNN-based models have better performances than the edge detection methods-based Canny and Sobel operators for extracting the trace and reducing noise,especially the DeepLabV3+***,the quantization results further prove the reliability of extracting the fracture *** a result,a case study with two types of traces(i.e.,on flat and uneven surfaces)demonstrates that the applied semantic-level computer vision detection is an accurate and efficient approach for characterizing the fracture trace of hard rock pillars.

关键词： Fracture trace Hard rock pillar Semantic-level computer vision Convolutional neural network(CNN) Underground space