34 resultados para effective atomic number

em Repositório Institucional UNESP - Universidade Estadual Paulista "Julio de Mesquita Filho"


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Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

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Solid-state compounds of general formula LnL(3).2H(2)O, where Ln is heavier trivalent lanthanides and yttrium, L is 4-chlorobenzylidenepyruvate have been synthetised.On heating these compounds decompose in steps. They lose the hydration water in the first step and the thermal decomposition of the anhydrous compounds occurs with the formation of oxochloride (Eu, Gd); mixture of oxide and oxochloride that decrease with increasing of atomic number of metal (Tb-Tm); or oxide (Yb, Lu, Y) as final residue, up to 900degreesC. The dehydration enthalpies found for terbium, holmium, ytterbium and yttrium compounds were: 34.93, 42.40, 57.39 and 62.24 kJ mol(-1), respectively.

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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

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Trichilia pallida Swartz is an Atlantic Forest shady climax tree of Meliaceae family that presents insecticide properties against chewing insects like as some family trees, making it interesting for forestry uses. Forty plants of Oito Pontas Farm population were collected in Bofete County, Santa Genebra Ecological Station in Campinas County, and Caetetus Ecological Station in Gélia County, all in the Sao Paulo State, Brazil. Leaf DNA analysis was used by RAPD method, that showed 10 highly polymorphic primers, with 72 dominant markers, used to estimate genetic diversity within and among populations. The polymorphism within populations varied from 90.3 to 97.2%, and the effective allele number varied from 1.46 ± 0.33 to 1.57 ± 0.33, while the average of genetic differentiation of populations varied from 0.27 ± 0.18 to 0, 33 ± 0.15. The gene diversity in the total population (H T) was 0.334 ± 0.02, while the average gene diversity within populations (H s) was 0.292 ± 0.017, and the coefficient of gene differentiation (G ST) was 0.125, Bofete and Campinas populations had the smallest Nei's genetic distance (0.049) and the distances of both with Gália were 0.117 and 0.107, respectively.

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Pós-graduação em Ciência e Tecnologia de Materiais - FC

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This study aimed to evaluate the genetic diversity and relatedness of 24 accessions of Theobroma grandiflorum, originating from three units of Embrapa, aiming their use as parents in hybridization specie programs. The genetic markers used were heterologous microsatellite loci developed for cocoa. In the population studied 45 alleles were found. The effective average number of alleles per locus (2.33) was less than the average number of alleles per locus (3.21), indicating that many alleles have low frequency. The observed heterozygosity at polymorphic loci ranged from 0.33 to 1.00 with a mean of 0.54 and expected heterozygosity ranged from 0.48 to 0.76 with a mean of 0.54. The fixation index medium between loci (0.003) was not significantly different from zero. The estimate of relatedness between pairs of individuals indicates that some may be relatives, including half-brothers and clones. The results suggest that the accesses of T. grandiflorum analyzed contain a moderate level of genetic diversity and absence of inbreeding and therefore great potential for use in breeding programs.

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In chemical industry, petrochemical and oil refinery may be found situations that working pressures and very high temperatures, and alloys that comprise such equipment must have specific characteristics such. As a way to ensure that the materials are as designed, companies have some specific techniques, and one of them is X-ray fluorescence spectrometry, which allows its application in devices small and lightweight, which ensures its portability in field use. This technique however, has some shortcomings such as the impossibility of detecting carbon and other elements of low atomic number which can generate false identifications of elements that are not in the league or non-detection of existing elements. Therefore, this study investigated the reliability of this method using the apparatus Niton XL3t 800 and may conclude that their results are reliable and can be used to assist in ensuring the operational integrity of the production units of these companies

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The stability of a Bose-Einstein condensed state of trapped ultra-cold atoms is investigated under the assumption of an attractive two-body and a repulsive three-body interaction. The Ginzburg-Pitaevskii-Gross (GPG) nonlinear Schrodinger equation is extended to include an effective potential dependent on the square of the density and solved numerically for the s-wave. The lowest collective mode excitations are determined and their dependences on the number of atoms and on the strength of the three-body force are studied. The addition of three-body dynamics can allow the number of condensed atoms to increase considerably, even when the strength of the three-body force is very small compared with the strength of the two-body force. We study in detail the first-order liquid-gas phase transition for the condensed state, which can happen in a critical range of the effective three-body force parameter.

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The quantitative effect in the maximum number of particles and other static observables was determined. A deviation in the harmonic trap potential that is effective only outside the central part of the potential, with the addition of a term that is proportional to a cubic or quartic power of the distance was considered. Results showed that this study could be easily transferred to other trap geometries to estimate anharmonic effects.

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The influence of small amounts of bovine serum albumin (BSA) (nM concentration) on the lateral organization of phospholipid monolayers at the air-water interface and transferred onto solid substrates as one-layer Langmuir-Blodgett (LB) films was investigated. The kinetics of adsorption of BSA onto the phospholipid monolayers was monitored with surface pressure isotherms in a Langmuir trough, for the zwitterionic dipalmitoylphosphatidyl ethanolamine (N,N-dimethyl-PE) and the anionic dimyristoylphosphatidic acid (DMPA). A monolayer of N,N-dimethyl-PE or DMPA incorporating BSA was transferred onto a solid substrate using the Langmuir-Blodgett technique. Atomic force microscopy (AFM) images of one-layer LB films displayed protein-phospholipid domains, whose morphology was characterized using dynamic scaling theories to calculate roughness exponents. For DMPA-BSA films the surface is characteristic of self-affine fractals, which may be described with the Kardar-Parisi-Zhang (KPZ) equation. on the other hand, for N,N-dimethyl-PE-BSA films, the results indicate a relatively flat surface within the globule. The height profile and the number and size of globules varied with the type of phospholipid. The overall results, from kinetics of adsorption on Langmuir monolayers and surface morphology in LB films, could be interpreted in terms of the higher affinity of BSA to the anionic DMPA than to the zwitterionic N,N-dimethyl-PE. Furthermore, the effects from such small amounts of BSA in the monolayer point to a cooperative response of DMPA and N,N-dimethyl-PE monolayers to the protein. (c) 2005 Elsevier B.V. All rights reserved.

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In this work we discuss the effect of the quartic fermion self-interaction of Thirring type in QED in D=2 and D=3 dimensions. This is done through the computation of the effective action up to quadratic terms in the photon field. We analyze the corresponding nonlocal photon propagators nonperturbatively in k/m, where k is the photon momentum and m the fermion mass. The poles of the propagators were determined numerically by using the MATHEMATICA software. In D=2 there is always a massless pole whereas for strong enough Thirring coupling a massive pole may appear. For D=3 there are three regions in parameter space. We may have one or two massive poles or even no pole at all. The interquark static potential is computed analytically in D=2. We notice that the Thirring interaction contributes with a screening term to the confining linear potential of massive two-dimensional QED (QED(2)). In D=3 the static potential must be calculated numerically. The screening nature of the massive QED(3) prevails at any distance, indicating that this is a universal feature of D=3 electromagnetic interaction. Our results become exact for an infinite number of fermion flavors.

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Exact bounded solutions for a fermion subject to exponential scalar potential in 1 + 1 dimensions are found in closed form. We discuss the existence of zero modes which are related to the ultrarelativistic limit of the Dirac equation and are responsible for the induction of a fractional fermion number on the vacuum.

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We solve Einstein equations on the brane to derive the exact form of the brane-world-corrected perturbations in Kerr-Newman singularities, using Randall-Sundrum and Arkani-Hamed-Dimopoulos-Dvali (ADD) models. It is a consequence of such models that Kerr-Newman mini-black holes can be produced in LHC. We use this approach to derive a normalized correction for the Schwarzschild Myers-Perry radius of a static (4+n)-dimensional mini-black hole, using more realistic approaches arising from Kerr-Newman mini-black hole analysis. Besides, we prove that there are four Kerr-Newman black hole horizons in the brane-world scenario we use, although only the outer horizon is relevant in the physical measurable processes. Parton cross sections in LHC and Hawking temperature are also investigated as functions of Planck mass (in the LHC range 1-10 TeV), mini-black hole mass, and the number of large extra dimensions in brane-world large extra-dimensional scenarios. In this case a more realistic brane-effect-corrected formalism can achieve more precisely the effective extra-dimensional Planck mass and the number of large extra dimensions-in the Arkani-Hamed-Dimopoulos-Dvali model-or the size of the warped extra dimension-in Randall-Sundrum formalism.

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The stability of an attractive Bose-Einstein condensate on a joint one-dimensional optical lattice and an axially symmetrical harmonic trap is studied using the numerical solution of the time-dependent mean-field Gross-Pitaevskii equation and the critical number of atoms for a stable condensate is calculated. We also calculate this critical number of atoms in a double-well potential which is always greater than that in an axially symmetrical harmonic trap. The critical number of atoms in an optical trap can be made smaller or larger than the corresponding number in the absence of the optical trap by moving a node of the optical lattice potential in the axial direction of the harmonic trap. This variation of the critical number of atoms can be observed experimentally and compared with the present calculations.