Single Crystal Fiber
Mostrando 1-12 de 13 artigos, teses e dissertações.
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1. A new circular photonic crystal fiber for effective dispersion compensation over E to L wavelength bands
This paper presents a new circular photonic crystal fiber (C-PCF) for effective dispersion compensation covering E to L wavelength bands ranging from 1360-1625 nm. To investigate its guiding properties, finite element method (FEM) with a perfectly matched layer absorbing boundary condition is used. From our numerical simulation, it is found that the designed
J. Microw. Optoelectron. Electromagn. Appl.. Publicado em: 2013-12
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2. Crescimento de fibras de LiYF4 dopadas com Nd3+ e Er3+ para aplicações em lasers de estado sólido / SINGLE FIBER CRYSTAL GROWTH OF Nd3+ AND Er3+- DOPED LiYF4 FOR SOLID STATE LASER APPLICATIONS
In the present work, we studied the growth of single crystal fibers of LiYF4 (YLF) doped with Er3+ or Nd3+ by the resistive micro-pulling-down (-PD) tecnhique. A new method for crucible preparation was developed to improve the growth process. The use of better-built crucibles allows their use in more than one experiment, increasing the process reproducibilit
Publicado em: 2008
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3. Nanofibras de carbono verticalmente alinhadas:: estudo do crescimento por microscopia eletrônica de transmissão
This work is about the growth of vertically aligned Carbon Nanofibers - CNFs - grown by Plasma Enhanced Chemical Vapour Deposition - PECVD. Being so, a detailed study of catalyst particle is necessary and Transmission Electron Microscopy - TEM - is fundamental for this knowledge. Some analytical techniques associated to TEM were used: Bright and Dark Field I
Publicado em: 2008
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4. SINGLE PHOTON COUNTING IN THE NEAR- AND MID-INFRARED VIA FREQUENCY UP-CONVERSION APPLIED TO QUANTUM COMMUNICATIONS / CONTAGEM DE FÓTONS NO INFRAVERMELHO PRÓXIMO E MÉDIO VIA CONVERSÃO DE FREQÜÊNCIAS APLICADA A COMUNICAÇÕES QUÂNTICAS
Two single photon counting devices, operating at near- and mid-infrared wavelengths, are introduced and experimentally investigated. Both use a twostage technique, comprised of an initial frequency up-conversion procedure inside a nonlinear crystal followed by a silicon avalanche photodiode. Whereas the first project consists on detection of single photons a
Publicado em: 2007
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5. CRESCIMENTO E CARACTERIZAÇÃO DE FIBRAS MONOCRISTALINAS DE FLUORETOS DO TIPO LiY1-xTRxF4 (TR = TERRAS-RARAS) / GROWTH AND CHARACTERIZATION OF FLUORIDE CRYSTALLINE FIBRES TYPE LiY1-xTRxF4 (RE = RARE-EARTH)
In this work we present the growth and characterization of LiF and pure and rare-earth doped (Er and Nd) yttrium-lithium tetra-fluoride (LiYF4 or YLF) by the micro-pulling-down technique (µ-PD). The use of this technique is original for the present purpose. A m-PD prototype in the resistive mode was firstly built to understand the most important operational
Publicado em: 2005
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6. Caracterização espectroscópica de possíveis meios ativos para lasers de Nd3+ e Tm3+ / Spectroscopic characterization of possible Nd3+ and Tm3+ laser active media
In this work we have made an important contribution to the growing research of new laser materials that can be pumped by low cost diode lasers or by the Upconversion process to operate in the near-infrared and visible spectral regions. Three kinds of hosts, doped with the rare earth ions (Nd3+ and Tm3+) were studied, and they present potential characteristic
Publicado em: 2003
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7. Preparação e caracterização de fibras monocristalinas de SrTiO3, SrTi(1-X)RuXO3 e de Sr2RuO4. / Preparation and characterization of SrTiO3, SrTi(1-X) RuXO3 and Sr2RuO4 single crystal fibers.
Neste trabalho desenvolvemos processos de crescimento e caracterização de fibras monocristalinas de SrTiO3 e Sr2RuO4 puros e como soluções sólidas através da técnica LHPG (laser heated pedestal growth). Esses processos são descritos desde as sínteses dos compostos, preparação dos nutrientes e sementes necessários para aplicação da técnica. Alg
Publicado em: 1996
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8. A'-form RNA double helix in the single crystal structure of r(UGAGCUUCGGCUC).
Here we demonstrate the presence of the A'-RNA conformation using the single crystal structure of a tridecamer: r(UGAGCUUCGGCUC). The average A'-RNA conformation deduced from X-ray fiber diffraction data had only been available previously, but now the presence of the A'-RNA conformation has been found in a single crystal structure for the first time. Statist
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9. The propeller DNA conformation of poly(dA).poly(dT).
Physical properties of the DNA duplex, poly(dA).poly(dT) differ considerably from the alternating copolymer poly(dAT). A number of molecular models have been used to describe these structures obtained from fiber X-ray diffraction data. The recent solutions of single crystal DNA dodecamer structures with segments of oligo-A.oligo-T have revealed the presence
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10. X-ray diffraction studies of fibers and crystals of deoxygenated sickle cell hemoglobin.
Paracrystalline fibers of deoxygenated sickle hemoglobin in erythrocytes or concentrated solutions exhibit a phase transformation to a fully crystalline state. X-ray diffraction patterns of the fiber and crystallites are similar except in two respects: the equatorial spacings of the fibers suggest that they pack into a square lattice with a = 220 A, whereas
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11. Analysis of the PilQ Secretin from Neisseria meningitidis by Transmission Electron Microscopy Reveals a Dodecameric Quaternary Structure
PilQ is a member of the secretin family of outer membrane proteins and is specifically involved in secretion of type IV pili in Neisseria meningitidis, Neisseria gonorrhoeae, and Pseudomonas aeruginosa. The quaternary structure of PilQ from N. meningitidis was analyzed by transmission electron microscopy by using a negative stain. Single particle averaging w
American Society for Microbiology.
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12. Template-assisted filament growth by parallel stacking of tau
Tau Filaments are found in >20 neurodegenerative diseases. Yet, because of their enormous molecular weights and poor tendency to form highly ordered 3D crystal lattices, they have evaded high-resolution structure determination. Here, we studied 25 derivatized tau mutants by using electron paramagnetic resonance and fluorescence spectroscopy to report structu
National Academy of Sciences.