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681.
Rejane M. Ribeiro Teixeira C.E.T. Gonçalves da Silva 《Solid State Communications》1979,32(11):1031-1035
The cluster-Bethe-Lattice method is applied to a model two-band alloy. Intra-atomic Coulomb interactions are taken into account within the Hartree-Fock approximation. Charge transfer effects are treated self-consistently. A numerical calculation with parameters appropriate for the AuAg system yields results which are in qualitative agreement with experiments. 相似文献
682.
Nelson Dur’an Adriane M. F. Mllagres Elisa Esposito Emilia Curotto Carolina Aguirre Maria Francisca S. Teixeira Sonia M. S. Carvalho Ormezinda C. C. Fernandes 《Applied biochemistry and biotechnology》1995,53(2):155-162
A plate-agar technique for fungal screening was applied to evaluate the xylanolytic activities of 18Penicillium janthinellum and 10Aspergillus sydowi species from the Amazon region. In order to compare these genera with those of other regions, oneAspergillus sp., one P.janthinellum, and 12 unknown genera from the southern region of Chile were studied. From these fungi strain,A. sydowi (56 strain) (25.2 IU/mL),P. janthinellum (671 strain) (47.3 IU/mL) from Amazonia,P. janthinellum (X4Z2 strain) (9.5 IU/mL), and anAspergillus sp. (X2M1 strain) (33.3 IU/mL) from the southern region of Chile were identified. 相似文献
683.
J Feuer E.J. Janowski G Ladas C Teixeira 《Journal of Computational Analysis and Applications》2000,2(3):237-252
We investigate the asymptotic behavior, the oscillatory character, and theperiodic nature of solutions of the difference equation
where
is a real parameter and the initial conditions arearbitrary nonzero real numbers. 相似文献
684.
Aloir A. Merlo Aline Tavares Sherdil Khan Marcos J. Leite Santos Sergio Ribeiro Teixeira 《Liquid crystals》2018,45(2):310-322
Coumarins have been used in a wide range of applications, such as dye-sensitised solar cells, laser dyes and optical sensors. In order to further explore the properties of these materials, three new coumarin derivatives were obtained with different terminal arylalkyne linkages to the 6-position of the coumarin core. The synthesised materials were characterised by NMR, absorption and emission spectroscopy, and the liquid crystal properties were investigated through differential scanning calorimetry and polarised optical microscopy. In addition, dye-sensitised solar cells were assembled to evaluate the photoelectrochemical properties of the materials. Only the coumarin with a naphthyl group exhibited stable smectic A and nematic mesophases. All the coumarins were photoemissive in the range 420–461 nm. The adsorption of these dyes on TiO2 was observed by UV–vis spectroscopy; in addition, by incident photon-to-electron conversion efficiency and I–V curves, photocurrent generation was observed. 相似文献
685.
Schumacher HC Alves M Leite CA Santos JP Neto ET Murakami MM Galembeck F do Amaral M 《Journal of colloid and interface science》2007,305(2):256-263
Stable cationic latices were prepared by charge inversion of anionic styrene-acrylic copolymer latices upon binding Al3+ and Fe3+ ions. This is achieved by stabilizing the latices with a high-HLB (hydrophile-lypophile balance) nonionic surfactant that imparts strong steric stability to the latex, even in the presence of high concentrations of multivalent counterions while these are bound to the latex anionic sites. The cationic latices thus prepared have good stability properties, and the same procedure should be applicable to essentially any latex-carrying anionic sites. Analytical ESI-TEM images show that particle-bound iron is concentrated at the particle borders, but it is also found in the particle bulk. 相似文献
686.
Ruzene DS Gonçalves AR Teixeira JA de Amorim MT 《Applied biochemistry and biotechnology》2007,137(1-12):573-582
Sugar cane bagasse pulps were obtained by ethanol/water organosolv process under acid and alkaline conditions. The best condition of acid pulping for the sugarcane bagasse was 0.02 mol/L sulfuric acid at 160 degrees C, for 1 h, whereas the best condition for alkaline pulping was 5% sodium hydroxide (base pulp) at 160 degrees C, for 3 h. For the residual lignin removal, the acid and alkaline pulps were submitted to a chemical bleaching using sodium chlorite. Pulps under acid and alkaline conditions bleached with sodium chlorite presented viscosities of 3.6 and 7.8 mPa x s, respectively, and mu-kappa numbers of 1.1 and 2.4, respectively. The pulp under acid condition, bleached with sodium chlorite was used to obtain carboxymethylcellulose (CMC). CMC yield was 35% (pulp based), showing mass gain after the carboxymethylation reaction corresponding to 23.6% of substitution or 0.70 groups -CH(2) COONa per unit of glucose residue. The infrared spectra showed the CMC characteristic bands and by the infrared technique it was possible to obtain a substitution degree (0.63), similar to the substitution degree calculated by mass gain (0.70). 相似文献
687.
688.
Russo J Tavares JM Teixeira PI Telo da Gama MM Sciortino F 《Physical review letters》2011,106(8):085703
We introduce a microscopic model for particles with dissimilar patches which displays an unconventional "pinched" phase diagram, similar to the one predicted by Tlusty and Safran in the context of dipolar fluids [Science 290, 1328 (2000)]. The model-based on two types of patch interactions, which account, respectively, for chaining and branching of the self-assembled networks-is studied both numerically via Monte Carlo simulations and theoretically via first-order perturbation theory. The dense phase is rich in junctions, while the less-dense phase is rich in chain ends. The model provides a reference system for a deep understanding of the competition between condensation and self-assembly into equilibrium-polymer chains. 相似文献
689.
Teixeira JM Ventura J Araujo JP Sousa JB Wisniowski P Cardoso S Freitas PP 《Physical review letters》2011,106(19):196601
We report an inelastic electron tunneling spectroscopy study on MgO magnetic junctions with thin barriers (0.85-1.35 nm). Inelastic electron tunneling spectroscopy reveals resonant electronic trapping within the barrier for voltages V>0.15 V. These trapping features are associated with defects in the barrier crystalline structure, as confirmed by high-resolution transmission electron microscopy. Such defects are responsible for resonant tunneling due to energy levels that are formed in the barrier. A model was applied to determine the average location and energy level of the traps, indicating that they are mostly located in the middle of the MgO barrier, in accordance with the high-resolution transmission electron microscopy data and trap-assisted tunneling conductance theory. Evidence of the influence of trapping on the voltage dependence of tunnel magnetoresistance is shown. 相似文献
690.
Given a pair of planar curves, one can define its generalized area distance, a concept that generalizes the area distance of a single curve. In this paper, we show that the generalized area distance of a pair of planar curves is an improper indefinite affine spheres with singularities, and, reciprocally, every indefinite improper affine sphere in ${\mathbb {R}^3}$ is the generalized distance of a pair of planar curves. Considering this representation, the singularity set of the improper affine sphere corresponds to the area evolute of the pair of curves, and this fact allows us to describe a clear geometric picture of the former. Other symmetry sets of the pair of curves, like the affine area symmetry set and the affine envelope symmetry set can be also used to describe geometric properties of the improper affine sphere. 相似文献