Anisotropic Crystals
Mostrando 1-12 de 20 artigos, teses e dissertações.
-
1. Effects of Birefringence on the Electromagnetic Guidance of Structures Produced by Femtosecond Laser
Abstract Analysis of the state of polarization of light guided by structures recorded in lithium niobate and lithium fluoride crystals indicates that the recording method is determinant in the formation of birefringent structures. Each structure was written with a single and continuous translation of the crystal transversally to the laser beam. Birefringence
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2018-06
-
2. Quinolines by Three-Component Reaction: Synthesis and Photophysical Studies
The synthesis of five quinolines 8-octyloxy-4-[4-(octyloxy)phenyl]quinoline and 6-alkoxy- 2-(4-alkoxyphenyl)-4-[(4-octyloxy)aryl]quinolines are described by three-component coupling reaction mediated by Lewis acid FeCl3 and Yb(OTf)3. 4-n-octyloxybenzaldehyde, anisaldehyde, 4-n-octyloxyaniline p-anisidine, and 1-ethynyl-4-heptyloxybenzene, 1-ethynyl-4-octylox
J. Braz. Chem. Soc.. Publicado em: 2015-03
-
3. GROWTH AND CHARACTERIZATION OF OPTICAL CRYSTALS AND PURE L-ASPARAGINE L-ASPARAGINE RADIATED. / CRESCIMENTO E CARACTERIZAÇÃO ÓPTICA DE CRISTAIS DE L-ASPARAGINA PURA E L-ASPARAGINA IRRADIADA.
Neste trabalho apresentamos os resultados do crescimento de cristais de L-Asparagina●H2O e do estudo de suas propriedades ópticas, lineares e não lineares, do cristal como é crescido e após ser submetido a altas doses de raios-X. Os cristais foram crescidos em solução aquosa pelo método de evaporação lenta do solvente. Foram realizadas medidas
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 15/02/2012
-
4. Aplicação da técnica de elipsometria de emissão para caracterização de materiais luminescentes
In this work we demonstrated the potential of the emission ellipsometry in the scope of the Stokes theory for electromagnetic field to the photophysics study of luminescent materials, in addition we introduce a new methodology using an achromatic quarter-wave plate. Moreover, the use of linearly polarized light allowed "selectively" the study of various phot
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 07/02/2012
-
5. Estudo estrutural de nanossistemas semicondudores e semicondutores implantados por difração de raios-X de n-feixes / Structural study of semiconductors nanosystems and implanted semiconductors by means of n-beams X-ray diffraction
In this paper, X-ray multiple diffraction (MD) associated with the advantages of synchrotron radiation appears as a high-resolution microprobe and it is used to obtain relevant contributions to the study of structural properties of semiconductor materials, as they present themselves nanosystems epitaxial or implanted with ions. The study and detection of neg
Publicado em: 2010
-
6. Cálculo da elasticidade de cristais líquidos nemáticos através de métodos da geometria diferencial
Found on Frank free energy relation, the bulk elastic constants of the nematic liquid crystals are computed in this work through an approach based on the affine connection method. This consists in the deformation of the isotropic fluid sferical molecules until they acquire an elipsoidal shape, likely the estimated nematic molecules form. Herewith the method
Publicado em: 2007
-
7. Transições de fase em polimeros liquido-cristalinos de cadeia lateral / Phase transitions in side-chain liquid-cristaline polmers
Polymeric liquid crystals are materials that combine properties of both polymers and liquid crystals. These polymers can be thought as block copolymers made of ftexible and rigid molecular blocks. As in flexible block copolymers, the macrophase separation originated from the repulsion between different blocks is frustrated by the connectivity constraint impo
Publicado em: 2007
-
8. Frenkel-exciton-polaritons in organic microcavities
We study organic microcavities in the strong coupling regime. The cavity exciton-polariton dispersion relations and quantum states are derived in using a microscopic theory. We consider the two cases of anisotropic organic crystals with one and two molecules per unit cell. In general, the cavity exciton-polaritons are a coherent superposition of both cavity
Brazilian Journal of Physics. Publicado em: 2006-06
-
9. Estudos estruturais em compostos de interesse farmacológicos contendo átomos pesados / Structural studies of pharmacological interested compound containing heavy atoms
The determination of the three-dimensional structures of heavy-metal chelates and of some potentially useful chelating agents is a very important to01 in the study of complexes that may act as antidotes against poisoning by ingestion of heavy metals. A detailed knowledge of these complexes is expected to assist in the design of molecular structures and proce
Publicado em: 2004
-
10. Studies on the anisotropic properties of MgB2
This paper presents a review on reported anisotropic properties of MgB2. The first direct measurement of an anisotropic superconducting property in MgB2was achieved for the bulk nucleation field Hc2, in samples of aligned crystallites. A ratio / ~ 1:7 was found
Brazilian Journal of Physics. Publicado em: 2002-09
-
11. Estados críticos orientacionais em cristais líquidos liotrópicos induzidos por campos magnéticos. / Orientations critical states in lyotropic liquid crystals induced by magnetic fields.
Liquid crystalline structures are found in materials made from molecules which are anisotropic in shape; such material are characterized mainly by a long range orientational order. In the nematic phase, the rodlike molecules tend to align parallel to each other. The average orientation defines a unit vector, called director n. Lyotropic liquid crystals are u
IBICT - Instituto Brasileiro de Informação em Ciência e Tecnologia. Publicado em: 19/12/2000
-
12. Estudos dos momentos magneticos em solidos por ressonancia paramagnetica eletronica
Electron Paramagnetic Resonance (EPR) of magnetic impurities (3d e 4f) in single crystals and powdered samples is a subject of importance in the study of magnetic impurities in solids. The study and analysis of the EPR spectra is the main subject of this work. We developed computational algoritms to simulate and fit EPR spectra, using a suitable Spin Hamilto
Publicado em: 2000