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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

Dipole (hyper)polarizabilities of neutral silver clusters

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Chinese Physics B 2016年第12期25卷 217-222页

作者： Francisco E Jorge Luiz G M de Macedo Departarnento de Fisica Universidade Fedoral do Espirito Santo 29060-900 Vitoria Brazil Unidade Academica de Fisica Universidade Federal de Campina Grande 58429-900 Campina Grande Brazil Faculdade de Biotecnologia ICB Universidade Federal do Para 66075-110 Belem Brazil

At the Douglas-Kroll-Hess （DKI4） level, the B3PW91 functional along with the all-eleclron relativistic basis sets of valence triple and quadruple zeta qualities are used to determine the structure, stability, and electronic properties of the small silver clusters （Agn, n ≤ 7）. The results presented in this study are in good agreement with the experimental data and theoretical values obtained at a higher level of theory from the literature. Static polarizability and hyperpolarizability are also reported. It is verified that the mean dipole polarizability per atom exhibits an odd-even oscillation and that the polarizability anisotropy is directly related to the cluster shape. In this article, the first study of hyperpolarizabilities of small silver clusters is presented. Except for the monomer, the second hyperpolarizabilities of the silver clusters are significantly larger than those of the copper clusters.

关键词： B3PW91 functional all-electron basis sets non-relativistic and DKH2 calculations silver clusters,dipole (hyper)polarizabilities

Consensus on Intervals of Communication Delay

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International Journal of Automation and computing 2018年第1期15卷 13-24页

作者： Heitor J.Savino Fernando O.Souza Luciano C.A.Pimenta Graduate Program in Electrical Engineering Federal University of Minas Gerais Institute of Computing Federal University of Alagoas Department of Electronic Engineering Federal University of Minas Gerais

This paper brings out a structured methodology for identifying intervals of communication time-delay where consensus in directed networks of multiple agents with high-order integrator dynamics is achieved. It is built upon the stability analysis of a transformed consensus problem which preserves all the nonzero eigenvalues of the Laplacian matrix of the associated communication topology graph. It is shown that networks of agents with first-order integrator dynamics can be brought to consensus independently of communication delay, on the other hand, for agents with second-order integrator dynamics, the consensus is achieved independently of communication delay only if certain conditions axe satisfied. Conversely, if such conditions axe not satisfied, it is shown how to compute the intervals of communication delay where multiple agents with second-order or higher-order can be brought to consensus. The paper is ended by showing an interesting example of a network of agents with second-order integrator dynamics which is consensable on the first time-delay interval, but as the time-delay increases, it loses consensability on the second time-delay interval, then it becomes consensable again on the third time-delay interval, and finally it does not achieve consensus any more on the fourth time-delay interval. This example shows the importance of analyzing consensus with time-delay in different intervals.

关键词： Time delay systems multi-agent systems consensus communication delay roots location.

Broadband Optical Active Waveguides Written by Femtosecond Laser Pulses in Lithium Fluoride

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Chinese Physics Letters 2014年第1期31卷 72-75页

作者： Ismael Chiamenti Francesca Bonfigli Anderson S. L. Gomes Rosa Maria Montereali Larissa N. da Costa Hypolito J. Kalinowski Federal University of Technology- Parang 80230-901 Curitiba Brazil ENEA C. R. Frascati Photonics Micro and Nanostructures Laboratory UTAPRAD-MNF V. E. Fermi 45 00044 Frascati (Rome) Italy Department of Physics Universidade Federai de Pernambuco necife Brazil

Broadband waveguiding through light-emitting strips directly written in a blank lithium fluoride crystal with a femtosecond laser is reported. Light guiding was observed at several optical wavelengths, from blue, 458 nm, to near-infrared, at 155nm. Visible photoluminescence spectra of the optically active F2 and F33 color centers produced by the fs laser writing process were measured. The wavelength-dependent refractive index increase was estimated to be in the order of 10-3-10-4 in the visible and near-infrared spectral intervals, which is consistent with the stable formation of point defects in LiF.

关键词： POINT defects CRYSTAL defects IMPURITY centers ANTISITE defects INTERSTITIALS FLUX pinning

Hole Burning in the Fock Space: from Single to Several Holes

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Chinese Physics Letters 2001年第11期18卷 1467-1469页

作者： B.Baseia J.M.C.Malbouisson Instituto de Fisica Universidade Federal de Goias74001-970GoianiaGOBrazil Instituto de Fisica Universidade Federal da Bahia40210-340SalvadorBABrazil

In our previous papers we have studied the production of a single hole in the photon number distribution of a field state [Phys. Lett. A 240 (1998) 277;253 (1999) 123]. In this letter we extend the procedure for the c... 详细信息

关键词： letter creation distribution

Glial fibrillary acidic protein levels are associated with global histone H4 acetylation after spinal cord injury in rats

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Neural Regeneration Research 2018年第11期13卷 1945-1952页

作者： Mayara Ferraz de Menezes Fabricio Nicola Ivy Reichert Vital da Silva Adriana Vizuete Viviane Rostirola Eisner Leder Leal Xavier Carlos Alberto Saraiva Goncalves Carlos Alexandre Netto Regis Gemerasca Mestriner Neurorehabilitation and Neural Repair Research Group Pontificia Universidade Catolica do Rio Grande do Sul Porto Alegre RS Brazil Graduate Program in Cellular and Molecular Biology Pontificia Universidade Catolica do Rio Grande do SUl Porto Alegre RS Brazil Department of Biochemistry Basic Science Institute Universidade Federal do Rio Grande do Sul Porto Alegre RS Brazil Graduate Program in Biosciences and Rehabilitation. Centro Universitairio Metodista IPA Porto Alegre RS Brazil

Emerging evidence has suggested global histone H4 acetylation status plays an important role in neural plasticity. For instance, the imbalance of this epigenetic marker has been hypothesized as a key factor for the development and progression of several neurological diseases. Likewise, astrocytic reactivity-a wellknown process that markedly influences the tissue remodeling after a central nervous system injury-is crucial for tissue remodeling after spinal cord injury（SCI）. However, the linkage between the above-mentioned mechanisms after SCI remains poorly understood. We sought to investigate the relation between both glial fibrillary acidic protein（GFAP） and S100 calcium-binding protein B（S100B）（astrocytic reactivity classical markers） and global histone H4 acetylation levels. Sixty-one male Wistar rats（aged ~3 months） were divided into the following groups： sham; 6 hours post-SCI; 24 hours post-SCI; 48 hours post-SCI; 72 hours post-SCI; and 7 days post-SCI. The results suggested that GFAP, but not S100B was associated with global histone H4 acetylation levels. Moreover, global histone H4 acetylation levels exhibited a complex pattern after SCI, encompassing at least three clearly defined phases（first phase： no changes in the 6, 24 and 48 hours post-SCI groups; second phase： increased levels in the 72 hours post-SCI group; and a third phase： return to levels similar to control in the 7 days post-SCI group）. Overall, these findings suggest global H4 acetylation levels exhibit distinct patterns of expression during the first week post-SCI, which may be associated with GFAP levels in the perilesional tissue. Current data encourage studies using H4 acetylation as a possible biomarker for tissue remodeling after spinal cord injury.

关键词： histones spinal cord injury glial fibrillary acidic protein S100 calcium-binding protein B neuralplasticity astrocyte ELISA-immunoassay recovery neural repair rats

On the Singular Effects in the Relativistic Landau Levels in Graphene with a Disclination

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Communications in Theoretical Physics 2018年第12期69卷 817-822页

作者： Rosinildo F.do Nascimento Diego Cogollo Edilberto O.Silva Moisés Rojas Cleverson Filgueiras Instituto de Fisica Universidade Federal de UberlandiaUberlandiaMGBrasil Unidade Academica de Fisica Universidade Federal de Campina GrandePOB 1007158109-970Campina Grande-PB Brazil Departamento de Fisica Universidade Federal do Maranhao65085-580Sao Luis-MABrazil Departamento de Fisica Universidade Federal de LavrasCaixa Postal 303737200-000Lavras-MGBrazil

The effect of a pseudo Aharonov-Bohm(AB) magnetic field generated by a disclination on a two-dimensional electron gas in graphene is addressed in the continuum limit within the geometric approach. The influence of the coupling between the spinor fields and the singular conical curvature is investigated, which shows that singularities have pronounced impact in the Hall conductivity. Moreover, the degeneracy related to the Dirac valleys is broken for negative values of the angular momentum quantum numbers, ?, including ? ≡ 0. In this case, a Hall plateau develops at the null filling factor. Obtaining the Hall conductivity by summing over the positive and the negative ?′s, the null Landau level is recovered and the plateau at the null filling factor disappears. In any case, the standard plateaus, which are seen in a flat graphene are not obtained with these curvature and singular effects.

关键词： Landau Levels Hall conductivity Graphene Elastic deformations

Dewetting in associating lattice gas model confined by hydrophobic walls

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Science China(Physics,Mechanics & Astronomy) 2019年第10期62卷 60-67页

作者： Tassylla OFonseca Marcia M.Szortyka Patricia Temes Cristina Gavazzoni Alan Bde Oliveira Marcia CBarbosa Instituto de Fsica Universidade Federal do Rio Grande do SulPorto Alegre 91501-970Brasil Universidade Federal de Santa Catarina Rua Pedro Joao PereiraMato Alto 88900-000Brasil Instituto Federal Catarinense Sao Bento do Sul 89283-064Brasil Instituto de Quimica Universidade Estadual de CampinasCampinas 13083-970Brasil Departamento de Fisica Universidade Federal de Ouro PretoOuro Preto 35400-000Brasil

The phase behavior of a two dimensional fluid confined within hydrophobic walls is obtained by Monte Carlo *** fluid is described by the associating lattice gas model which reproduces the density and diffusion anomalous behavior of *** confined fluid exhibits a liquid-liquid critical temperature which decreases with the decrease of the distance between the confining *** contact with the wall a dewetting is *** thickness of this interfacial layer is independent of the distance between the two *** for very small distances between the two walls no total depletion is observed and consequently no drying transition is present.

关键词： water lattice confined

Curcumin-Loaded Electrospun Fibers: Fluorescence and Antibacterial Activity

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Advanced Fiber Materials 2020年第5期2卷 256-264页

作者： Mário César Albuquerque de Oliveira Fernando Antonio Gomes da Silva Jr. Mateus Matiuzzi da Costa Nikifor Rakov Helinando Pequeno de Oliveira Institute of Materials Science Federal University of Sao Francisco ValleyJuazeiroBA 48920-310Brazil

The health benefits and sensing applications of curcumin-based systems depend on their prevailing photophysical and chemi-cal properties at a specific environment-the characteristic low solubility of curcumin in water hinders high-dosage based *** circumvent this drawback,curcumin has been incorporated in hydrophobic environments in ***,electrospun fibers of Eudragit L100 were loaded with curcumin and applied in fluorescence and antibacterial assays to evaluate prevailing physical and chemical properties in *** characteristic high loading degree of curcumin(250 mg/mL in Eudragit L100 solution)preserves not only the photophysical properties of molecules(such as the intrinsic fluorescence)but also the antibacterial activity of released molecules from electrospun fibers,characterizing an important strategy for improvement in the applicability potential of natural materials.

关键词： Curcumin Fluorescence Electrospinning Hydrophobic core