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Optical and structural properties of planar and channel waveguides based on sol gel Er3+ and Yb3+ co-doped SiO2-ZrO2 are reported. Microstructured channels with high homogeneous surface profile were written onto the surface of multilayered densified films deposited on SiO2/Si substrates by a femtosecond laser etching technique. The densification of the planar waveguides was evaluated from changes in the refractive index and thickness, with full densification being achieved at 900 degrees C after annealing from 23 up to 500 min, depending on the ZrO2 content Crystal nucleation and growth took place together with densification, thereby producing transparent glass ceramic planar waveguides containing rare earth-doped ZrO2 nanocrystals dispersed in a silica-based glassy host Low roughness and crack-free surface as well as high confinement coefficient were achieved for all the compositions. Enhanced NIR luminescence of the Er3+ ions was observed for the Yb3+- codoped planar waveguides, denoting an efficient energy transfer from the Yb3+ to the Er3+ ion. (C) 2012 Elsevier B.V. All rights reserved.; FAPESP; FAPESP; CAPES; CAPES; CNPq; CNPq

Nesse trabalho investigamos a influência de defeitos nas propriedades estruturais, eletrônicas e mecânicas de nanotubos de parede simples (SWCNT), em feixes de nanotubos e em nanotubos de parede múltipla (MWCNT). Todos os nossos resultados foram obtidos utilizando uma teoria de primeiros princípios de energia total, a Teoria do Funcional da Densidade (DFT). Investigamos as propriedades estruturais para quatro defeitos em nanotubos de parede simples: Stone-Wales (5577), monovacância e duas divacâncias (585) e (555777), e o comportamento da energia de formação em função do diâmetro para as quatro estruturas. Observamos que as divacâncias apresentam uma inversão de estabilidade, quando comparamos as energias de formação desses defeitos em nanotubos com o grafeno e, alám disso, as divacâncias são os defeitos mais importantes na modificação das propriedades de transporte em SWCNT. Estudamos a estabilidade e as propriedades de transporte desses sistemas e observamos que o defeito 585 é menos estável em grafeno devido à quebra de duas ligações dos pentágonos do defeito. O defeito 555777 torna-se mais estável do que o 585 para os CNT armchair (zigzag) com o diâmetro 40 °A (53 °A). Investigamos as propriedades estruturais e mecânicas de feixes de nanotubos com os defeitos do tipo vacância-vacância...

Neste trabalho desenvolvemos um potencial empírico para descrever as ligações químicas entre os átomos de silício, nitrogênio e hidrogênio usando a forma funcional de Tersoff. Exploramos as propriedades estruturais do nitreto de silício amorfo (a-SiNx:Hy) via simulação Monte Carlo e comparamos com dados experimentais. A boa descrição do sistema a-SiNx:Hy, para uma faixa de valores da concentração de nitrogênio (0

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The influence of current density, at the interval 5-100 mA cm-2, on the structural and magnetic properties of electrodeposited (Co 100-xNix)100-yWy alloys (x = 23-33.5 at. % Ni, y = 1.7-7.3 at. % W) was studied from a glycine-containing bath. W-content decreases with the increase of the current density magnitude. X-ray data have shown stabilization of hexagonal close packed, face centered cubic or a mixture of these structures by modulating the applied cathodic current density, for values lower than 50 mA cm-2. Two structural phase transitions were observed: one from hexagonal close packed to face centered cubic structural transition occurring for a current density of 20 mA cm -2, and another one, from cubic crystalline phase to amorphous state, which happens for values higher than 50 mA cm-2. These structural phase transitions seem to be associated with the W-content as well as average crystalline grain sizes that reduce with increasing the current density value. The grain size effect may explain the face centered cubic stabilization in Co-rich CoNiW alloys, which was initially assumed to be basically due to H-adsorption/incorporation. Magnetic properties of Co-rich CoNiW alloys are strongly modified by the current density value; as a result of the changes on the W-content and their structural properties© 2013 Elsevier B.V. All rights reserved.

This study was performed in order to determine the effect of the addition of different concentrations of glycerol and ethanol over functional and structural properties of zein-oleic acid films. Films were prepared from zein and oleic acid formulations, containing: 0, 10, 20 and 30% (w/w) of glycerol as plasticizer and 75, 80, 85, 90 and 95% (v/v) of ethanol as zein solvent. Water vapor permeability (WVP) at 4 and 24 C, opacity, water solubility and structural behavior of the film were assessed. The film water barrier properties, WVP and water solubility, were increased when higher ethanol concentration and lower glycerol concentration were used. Furthermore, WVP at 4 C was lower than WVP at 24 C due to the crystalline solid state of oleic acid at lower temperatures. Likewise, opacity, homogeneity and structure of the composite film were improved as ethanol increased and glycerol lowered. © 2013 Elsevier B.V. All rights reserved.

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES); Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); Processo FAPESP: 08/55736-3; Processo FAPESP: 2011/07453-5; The knowledge of structural properties of beds packed with particles from agro-industrial solid wastes is important for modeling and simulation of heat and mass transfer in solid-state fermentation (SSF) in packed-bed bioreactors. This paper addresses the experimental determination of particle and bulk densities (rho(part) and rho(bulk)) and porosities (epsilon) of beds packed with sugar cane bagasse (SCB), wheat bran (WB) and orange pulp and peel (OPP) and with mixtures of them. The effects of moisture content (MC) and packing technique on structural properties were evaluated. Microscopic analysis of cell-size was performed and the porosity along the fermentation was determined, as well as the endoglucanase yields for different proportions of a medium composed by SCB/WB. Results showed that MC affects significantly rho(part), rho(bulk) and epsilon. For OPP and WB, epsilon ranged from 0.4 to 0.7, depending on MC, and for SCB from 0.7 to 0.9, depending on MC and packing technique. For the composed media SCB:OPP:WB (1:2:2, weight) and SCB:WB (7:3)...

Hydrogenated amorphous and nanocrystalline silicon thin films deposited by Hot Wire (HW) and Radio-Frequency Plasma-Enhanced (RF) Chemical Vapor Deposition were Er-bium-implanted. Their pre-implantation structural properties and post-implantation optical properties were studied and cor-related. After one-hour annealing at 150ºC in nitrogen atmos-phere only amorphous films showed photoluminescence (PL) activity at 1.54 μm, measured at 5 K. After further annealing at 300oC for one hour, all the samples exhibited a sharp PL peak positioned at 1.54 m, with a FWHM of ~5 nm. Amorphous films deposited by HW originated a stronger PL peak than corresponding films deposited by RF, while in na-nocrystalline films PL emission was much stronger in sam-ples deposited by RF than by HW. There was no noticeable difference in Er3+ PL activity be-tween films implanted with 1x1014 atoms/cm2 and 5x1015 at-oms/cm2 Er doses.; FCT for a post-doctorate grant (SFRH/BPD/14919/2004)

According to the last national census, 35% of the Peruvian dwellings are made with adobe or tapial (rammed earth). In Cusco, a city located at the Peruvian highlands, around 75% of the building stock is constructed with earth. Besides, Cusco is relatively seismically active and thus seismic risk assessment studies are warranted. For example, on May 21, 1950, an earthquake seriously damaged almost all the buildings in Cusco, which a maximum estimated acceleration of 300 gals. This work looks at the structural properties of adobe buildings in Cusco for use in seismic risk assessment. The geometrical properties of typical dwellings from Cusco have been established according to a building-by-building survey carried out at the Catholic University of Peru (PUCP). Then, a database containing the principal geometrical properties of 30 dwellings has been created which has allowed the mean, standard deviation and probability density functions (PDF) to be defined for parameter such as storey height, wall length, etc.

This paper looks at the structural properties of adobe buildings in Cusco, Peru, for use in seismic risk assessment. The geometrical properties (typology) of adobe dwellings from Cusco have been established according to a building-by-building survey. Cusco has been chosen for this study as, according to the national census, around 80% of the building stock in this town is constructed with adobe. Furthermore, this region of the country is relatively seismically active and thus seismic risk assessment studies are warranted. Additional structural information of adobe buildings has been obtained from experimental tests carried out at the Catholic University of Peru. These tests have allowed the inter-storey drift capacity and the period of vibration of adobe buildings to be derived. A database containing the principal geometrical properties of 30 dwellings has been created which has allowed the mean, standard deviation and probability density functions (PDF) to be defined for each parameter such as storey height, wall length, etc. These properties are of use in a recently proposed probabilistic displacement- based earthquake loss assessment method (DBELA) which generates random populations of buildings based on this input data. The structural capacity of each random building is then predicted based on structural mechanics principles...

In this work is presented a study of the effect of calcination parameters namely, heating rate, calcination temperature, total calcination time and time at final temperature, on pore structural properties of Ti-MCM-41 materials. The materials were prepared by direct synthesis at ambient temperature and pressure, using tetraethoxysilane, titanium alcoxides, cationic surfactants and ammonia, as previously described and were characterised by X-ray diffraction, nitrogen adsorption at 77K and DR UV-Vis absorption spectroscopy. The Si/Ti values of the final calcined materials were determined by AA (Si) and ICP (Ti).

The replication origins (ORIs) of Schizosaccharomyces pombe, like those in most eukaryotes, are long chromosomal regions localized within A+T-rich domains. Although there is no consensus sequence, the interacting proteins are strongly conserved, suggesting that DNA structure is important for ORI function. We used atomic force microscopy in solution and DNA modelling to study the structural properties of the Spars1 origin. We show that this segment is the least stable of the surrounding DNA (9 kb), and contains regions of intrinsically bent elements (strongly curved and inherently supercoiled DNAs). The pORC-binding site co-maps with a superhelical DNA region, where the spatial arrangement of adenine/thymine stretches may provide the binding substrate. The replication initiation site (RIP) is located within a strongly curved DNA region. On pORC unwinding, this site shifts towards the apex of the curvature, thus potentiating DNA melting there. Our model is entirely consistent with the sequence variability, large size and A+T-richness of ORIs, and also accounts for the multistep nature of the initiation process, the specificity of pORC-binding site(s), and the specific location of RIP. We show that the particular DNA features and dynamic properties identified in Spars1 are present in other eukaryotic origins.

The prime mechanism by which p53 acts as a tumor suppressor is as a transcription factor regulating the expression of diverse downstream genes. The DNA-binding domain of p53 (p53DBD) interacts with defined DNA sites and is the main target for mutations in human primary tumors. Here, we show that the CWWG motif, found in the center of each consensus p53 half-site, is a key player in p53/DNA interactions. Gel-mobility-shift assays provide a unique opportunity to directly observe the various oligomeric complexes formed between p53DBD and its target sites. We demonstrate that p53DBD binds to p53 consensus sites containing CATG with relatively low cooperativity, as both dimers and tetramers, and with even lower cooperativity to such sites containing spacer sequences. p53DBD binds to sites containing CAAG and CTAG with measurable affinity only when imbedded in two contiguous p53 half-sites and only as tetramers (with very high cooperativity). There are three orders-of-magnitude difference in the cooperativity of interaction between sites differing in their non-contacted step, and further two orders-of-magnitude difference as a function of spacer sequences. By experimentally measuring the global structural properties of these sites, by cyclization kinetics of DNA minicircles...

Sexual selection and aerodynamic forces affecting structural properties of the flight feathers of birds are poorly understood. Here, we compared the structural features of the innermost primary wing feather (P1) and the sexually dimorphic outermost (Ta6) and monomorphic second outermost (Ta5) tail feathers of barn swallows (Hirundo rustica) from a Romanian population to investigate how sexual selection and resistance to aerodynamic forces affect structural differences among these feathers. Furthermore, we compared structural properties of Ta6 of barn swallows from six European populations. Finally, we determined the relationship between feather growth bars width (GBW) and the structural properties of tail feathers. The structure of P1 indicates strong resistance against aerodynamic forces, while the narrow rachis, low vane density and low bending stiffness of tail feathers suggest reduced resistance against airflow. The highly elongated Ta6 is characterized by structural modifications such as large rachis width and increased barbule density in relation to the less elongated Ta5, which can be explained by increased length and/or high aerodynamic forces acting at the leading tail edge. However, these changes in Ta6 structure do not allow for full compensation of elongation...

The structure of amorphous silicon (a-Si) has attracted wide interest over the recent decades. This substantial interest is twofold. Firstly, a-Si has many, highly significant, technological applications. Secondly, physically it is a fundamentally interesting material which has been regarded as a model system of a covalently bonded continuous random network (CRN). Such a CRN is a random network in which each atom has full four-fold coordination as the only specific structural feature. More recently, improvement of techniques has allowed greater insight into the structural properties of a-Si. Intriguing deviations, not only from the ideal CRN, but especially between different forms of a-Si have been observed. However, to date it remains unclear to what extent the formation method of a-Si influences its structural order. Another critically important parameter in the nature of a-Si is its thermal history. For example, a-Si formed by ion-implantation undergoes structural relaxation – or short-range ordering – upon thermal annealing to a new state that is close to an ideal CRN. It remains unclear however, if other forms of a-Si undergo structural relaxation to the same degree. Thus, despite its widespread use and decades of research...

The Spanish University Carlos III de Madrid has developed a new method in order to obtain nanostructured particles (ceramic, metallic and composite) with improved functional and structural properties. Spray pyrolysis is a way in order to obtain nanostructured particles. Optimization of synthesis process, evaluating the experimental parameter as pH, concentration and chemical nature of precursor solution, density, viscosity, carrier gas, temperature of reactor, etc. allow us to synthesize materials with improved properties. The group is looking for technical cooperation with companies.

Nesta tese estudamos a influência da incorporação de nitrogênio nas propriedades termomecânicas e estruturais em matrizes de carbono amorfo hidrogenado (a-C:H) e não hidrogenado (a-C). Duas técnicas de deposição foram utilizadas para o crescimento dos filmes. Os filmes hidrogenados foram preparados utilizando um sistema de glow discharge e as não hidrogenadas foram preparadas por IBAD. Um estudo preliminar foi feito em função do bias e a pressão do metano CH4, com o objetivo de escolher duas condições para a incorporação de nitrogênio. Deste primeiro estudo foi observado um aumento do coeficiente de dilatação térnica dos filmes de a-C:H com o aumento das ligações sp2. A partir desta série, uma segunda série de amostras com matriz tipo diamond-like e graphite-like de a-C:H foram estudadas, nas quais observamos que independente da matriz, a incorporação de nitrogênio produz um aumento no coeficiente de dilatação térnica (CTE) de até 9x10-6 C-1 para cerca de 6% de nitrogênio, próximo do valor do CTE do grafite (8x10-6C-1). A influência do nitrogênio no carbono amorfo aumenta a geração das hibridizações sp e sp2, o qual facilita a fornação de clusters grafíticos dentro dos filmes de a-C:H:Nx. O empilhamento dos clusters e a influência destes no CTE dos filmes são amplamente discutidos...

Structural characteristics of limbs bones provide insight into how an animal dynamically loads its limbs during life. Cause-and-effect relationships between loading and the osteogenic response it elicits are complex. In spite of such complexities, cross-sectional geometric properties can be useful indicators of locomotor repertoires. Typical comparisons use primates that are distinguished by broad habitual locomotor differences, usually with samples garnered from several museum collections. Intraspecific variability is difficult to investigate in such samples because behavior or life histories, which are tools for interpreting intraspecific variability, are limited. Clearly intraspecific variation both in morphology and behavior/life history exists. Here we expand an ongoing effort towards understanding intraspecific variation in limb structural properties by comparing free-ranging chimpanzees that have associated behavioral and life history data. Humeral and femoral data from eleven adult chimpanzees (Pan troglodytes) of Kibale National Park (Uganda) are compared to 29 adult habituated chimpanzees from Gombe (Tanzania), Mahale Mountains (Tanzania), and Taï Forest (Côte d’Ivoire) National Park communities. Overall, limb structural morphology of Kibale chimpanzees most resembles limb structural morphology of Mahale chimpanzees. Shape ratios and percentage cortical areas of Kibale chimpanzees are most similar to non-Gombe chimpanzees...

Cadmium sulphide (CdS) thin films were prepared by means of the chemical spray pyrolysis technique. The substrate temperature was varied in the range from 200 to 400°C. The structural properties of the semiconductor were characterized by X-ray diffraction; XRD patterns indicated the presence of single-phase hexagonal CdS. Direct band gap values of 2.37-2.41 eV were obtained. The refractive index is reported on depending on the substrate temperature, and was obtained from transmission spectra and from spectroellipsometry measurements. As a consequence, the optical parameters of the films were determined using the Swanepoel, Cauchy, Sellmeier and Wemple models. The resistivity of the films was found to vary in the range 10³ 10(5)Ω.cm, depending on the substrate temperature.

Building bilingual dictionaries from Wikipedia has been extensively studied in the area of computation linguistics. These dictionaries play a crucial role in Natural Language Processing(NLP) applications like Cross-Lingual Information Retrieval, Machine Translation and Named Entity Recognition. To build these dictionaries, most of the existing approaches use information present in Wikipedia titles, info-boxes and categories. Interestingly, not many use the structural properties of a document like sections, subsections, etc. In this work we exploit the structural properties of documents to build a bilingual English-Hindi dictionary. The main intuition behind this approach is that documents in different languages discussing the same topic are likely to have similar structural elements. Though we present our experiments only for Hindi, our approach is language independent and can be easily extended to other languages. The major contribution of our work is that the dictionary contains translation and transliteration of words which include Named Entities to a large extent. We evaluate our dictionary using manually computed precision. We generated a massive list of 72k tokens using our approach with 0.75 precision.

First principles calculations based on density functional theory were employed to investigate the structural, electronic, and magnetic properties of the Sc xCr1-xN (x =0.0, 0.25, 0.50, 0.75, and 1.0) compound, in the wurtzite structure. We applied the full-potential linearized augmented plane wave (FP-LAPW) method as implemented in the Wien2k code. The analysis of the structural properties revealed that the lattice constant increases linearly with the increment of the Sc atoms in the structure, in accord with Vegard's law, whereas the bulk modulus decreases. The studies of the electronic density showed that the ternary compounds of Sc xCr1-xN (x = 0.25, 0.50, and 0.75) exhibit a half-metallic behavior with magnetic spin polarization of 100% and a magnetic moment of 3 μβ/Cr-atom. The ferromagnetic behavior comes from a double exchange mechanism and hybridization of the Cr-d and N-p states that cross the Fermi level. These compounds are good candidates for applications in spintronics.