Výsledky vyhledávání - "J. A. K. Freire"

Polycyclic aromatic hydrocarbons from asphalt binder: extraction and characterization

Autor: J. A. K. Freire, Rivelino M. Cavalcante, Lucidalva S. Pinheiro, Paulo Roberto Nunes Fernandes, Ronaldo Ferreira do Nascimento, Sandra de Aguiar Soares, Jorge Barbosa Soares

Publikováno v: Journal of the Brazilian Chemical Society, Volume: 20, Issue: 2, Pages: 222-228, Published: 2009
Journal of the Brazilian Chemical Society v.20 n.2 2009
Journal of the Brazilian Chemical Society
Sociedade Brasileira de Química (SBQ)
instacron:SBQ

The asphalt binder, derived from petroleum, commonly employed in road paving contains PAHs (Polycyclic Aromatic Hydrocarbons) and a variety of other aliphatic and aromatic compounds. PAHs are pollutants that can induce health problems. This work aims

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_dedup___::d1d7cc4e3b0f0aa3f2ca85308bdbb48e
https://doi.org/10.1590/s0103-50532009000200005

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The role of surface roughness on the electron confinement in semiconductor quantum rings

Autor: G. A. Farias, J. Costa e Silva, Andrey Chaves, J. A. K. Freire

Publikováno v: Microelectronics Journal. 39:455-458

The electron energy spectrum of GaAs/Al0.30Ga0.70As quantum rings under applied magnetic fields is calculated, taking into account the existence of rough interfaces between materials. The Schrodinger equation, within the effective mass approximation,

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::1674cf4a90c217bbbc63e6c5b3fd1f9d
https://doi.org/10.1016/j.mejo.2007.07.019

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Influence of graded interfaces on the exciton energy of type-I and type-II Si/Si1-x Gex quantum wires

Autor: Marcos Henrique Degani, G. A. Farias, J. A. K. Freire, Valder N. Freire, Andrey Chaves, Jusciane Silva

Publikováno v: Journal of Materials Science. 42:2314-2317

The exciton properties of Si/Si 1-x Ge x cylindrical quantum wires (QWRs) are calculated using the variational method and taking into account the existence of an interface layer between the materials. We consider two possibilities for the conduction

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::3df4f4a725b8cf13f05877b60e544f05
https://doi.org/10.1007/s10853-006-0617-3

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Evaluation of Red Blood Cells of Healthy Subjects and Patients with Myelodysplastic Syndrome

Autor: G. A. Farias, S. M. M. Magalhaes, J. A. K. Freire, L. M. Rebelo, M. S. F. Barreto, Valder N. Freire, Ricardo Pires dos Santos, M. S. Pitombeira, E. F. Costa

Publikováno v: Microscopy and Microanalysis. 11:66-69

Atomic Force Microscopy (AFM) is a recent technique that allows evaluation of features in biological systems that could not be previously observed by other instruments. Red Blood Cells (RBC) have been extensively studied because of their relatively s

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::e05e753824cb7523a6d880ed8423e1f8
https://doi.org/10.1017/s1431927605050907

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Sporopollenin Nanostructure of Ilex paraguariensis A.St.Hil Pollen Grains

Autor: A. A. X. Santiago, Gustavo Arruda Bezerra, E. F. Costa, J. A. K. Freire, G. A. Farias, L. M. Rebelo, Ricardo Pires dos Santos, Valder N. Freire, Taiana Maia de Oliveira, Benildo Sousa Cavada

Publikováno v: Microscopy and Microanalysis. 11:78-81

Pollens appear like a fine to coarse powder that is liberated by the microsporangia of Gimnosperms and Angiosperms. The pollen grain wall, the sporoderm, envelopes the microgametophytes (male gametophytes), which produce the male gametes of seed plan

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::153539af83dd9701bff39a3f7031ea24
https://doi.org/10.1017/s1431927605050932

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Statistical analysis of topographic images of nanoporous silicon and model surfaces

Autor: J. B. da Silva, G. A. Farias, J. A. K. Freire, E.A. de Vasconcelos, B. E. C. A. dos Santos, Valder N. Freire, E. F. da Silva

Publikováno v: Microelectronics Journal. 36:1011-1015

We investigated the quantitative description of nanoporous silicon morphology and its correlation with electrical and optical properties. We performed first-order as well as second-order statistical analysis of AFM images of nanoporous silicon fabric

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::784100c56b04049a21345a7e8502c34c
https://doi.org/10.1016/j.mejo.2005.04.007

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A new method for luminescent porous silicon formation: reaction-induced vapor-phase stain etch

Autor: Elder A. de Vasconcelos, W.M. de Azevedo, B. E. C. A. dos Santos, J. A. K. Freire, E. F. da Silva

Publikováno v: physica status solidi (a). 202:1539-1542

We report a new method to form reproducible luminescent porous silicon layers in p-type and n-type substrates of low and high resisivity, with minimum apparatus and maximum simplicity. No equipment, formation of electrical contacts, illumination or a

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::4ba28d656397a060a41be2a574031eeb
https://doi.org/10.1002/pssa.200461177

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Excitons in type‐I type‐II strained Si/Si 1– x Ge x graded quantum well

Autor: Valder N. Freire, E. F. da Silva, G. A. Farias, J. A. K. Freire, J. Costa e Silva

Publikováno v: physica status solidi (c). 2:2958-2961

The exciton properties of Si/Si1–xGex strained quantum wells (QW's) are calculated taking into account interface and strain effects. Our numerical results allow us to conclude that interface fluctuations of only 10 A in a type-I (type-II) strained

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::b9f0ae92dccfde8ea4127f8959ce575a
https://doi.org/10.1002/pssc.200460729

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Lifetime of quasi‐bound states in open semiconductor quantum structures

Autor: C. L. N. de Oliveira, J. A. K. Freire, M. H. Degani, G. A. Farias, Valder N. Freire, J. S. de Sousa

Publikováno v: physica status solidi (c). 2:3031-3034

In this work, we compare two different methods to calculate the lifetime of quasi-bound states of one-dimensional semiconductor open quantum structures as a function of the size of confinement layers and barrier thicknesses that separate them from th

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::94c2e5a47bd921295179e5644a547648
https://doi.org/10.1002/pssc.200460718

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Differences of Stark shift behavior in Si/SiO2 quantum wells and quantum dots

Autor: J. A. K. Freire, Valder N. Freire, E. F. da Silva, J. S. de Sousa

Publikováno v: Applied Surface Science. 237:544-548

We report strong differences on the quantum-confined Stark effect (QCSE) behavior between Si/SiO 2 quantum dots (QDs) and quantum wells (QWs). In QWs, the QCSE exhibits strong non-linearities, which can be fitted to second and/or fourth order polynom

Externí odkaz: https://explore.openaire.eu/search/publication?articleId=doi_________::1bb12c7a23551b4ad9c700a4ad822341
https://doi.org/10.1016/j.apsusc.2004.06.156

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