Materials Literature
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We study numerically the interaction between particles in a nematic liquid crystal mediated by its elastic distortions with the aid of the Landau-de Gennes continuum theory. We consider the cases where two particles impose rigid normal anchoring on their surfaces and are accompanied by a hyperbolic hedgehog defect. As…
The 31 P-NMR spectra of europium complexes with β-diketones and phosphine oxides in CDCl 3 , DMSO- d 6 , toluene- d 8 with dissolved fluorinated polymers, and fluorinated solvent were investigated as well as the temperature dependence of these spectra. When a mixture of europium complex 1 and 1.0 molar equivalent of t…
Abstract Inhibitory action of hydroxylated cationic gemini surfactants on corrosion of mild steel [MS] in 1 M hydrochloric acid medium is studied by gravimetric, electrochemical polarization and electrochemical impedance spectroscopic (EIS) techniques. The results obtained reveal that these compounds are very efficien…
Abstract Lipase‐catalyzed ring‐opening bulk polymerizations of 6( S )‐methyl‐morpholine‐2,5‐dione (MMD) were investigated. Selected commercial lipases were screened as catalysts for MMD polymerization at 100 °C. Polymerizations catalyzed with 10 wt % porcine pancreatic lipase type II crude (PPL), lipase from Pseudomon…
Comprehensive temperature-programmed reduction, X-ray diffraction and diffuse reflectance spectroscopy studies were conducted on a stable nickel (10.5%) catalyst obtained through conventional impregnation of a sol-gel made support of g-Al2O3, to elucidate the interactions between nickel oxide and support. The results…
We applied photoalignment technology to liquid-crystal-on-silicon microdisplays and characterized their performance. A three-step photoexposure method was developed to solve problems with alignment disturbances on reflective silicon panels. The azimuthal and polar anchoring energies of photoalignment layers produced b…
This paper describes a wet-etching technique that solves the major difficulty of fine patterning a c-axis oriented polycrystalline ZnO film. The technique uses aqueous NH/sub 4/Cl with electrolytically added copper ions and convection flow, and for the first time, allows the ZnO film to be etched 1) with controlled et…
In this paper photo-electrochemical etching of silicon in HF-based solutions is employed as a versatile technique for fabrication of original silicon microstructures, alternative to commonly used methods. Photo-electrochemical etching, a well known technique for regular macropore formation, has been exploited to produ…
A measurements-based electrical method for locating partial discharges (PD) in transformers is described in the paper. This location method relies on the series resonance frequencies of the signals produced at the transformer terminals by a discharge on the winding. Based on the equivalent circuit of plain disc type w…
With the increasing demand for freshly cut vegetables, a substantial potential exists in developing minimally processed sweet potato products. This study was undertaken to determine the effects of semipermeable polymeric materials and modified atmosphere packaging (MAP) on quality changes and microbial growth in shred…
A novel process for low‐density alumina foams has been studied. Aqueous acidic sucrose solution containing aluminum nitrate when concentrated by heating formed a viscous resin. The resin mixed well with aqueous alumina slurry and the resulting powder‐filled resin underwent foaming on heating in a Teflon mold. The gree…
Mandelate racemase (MR, EC 5.1.2.2) from Pseudomonas putida catalyzes the Mg(2+)-dependent 1,1-proton transfer that interconverts the enantiomers of mandelate. Crystal structures of MR reveal that the phenyl group of all ground-state ligands is located within a hydrophobic cavity, remote from the site of proton abstra…
Aqueous gels derived from three cationic 24-nor 3,12-dihydroxy cholane (DC) derivatives with N-methyl-2-pyrrolidinone (NMP), N-methylmorpholine (NMM), and 1,4-diazabicyclo[2.2.2]octane (DABCO) at the side chain positions have been exhaustively characterized by small-angle neutron-scattering experiments. Although the m…
Density functional molecular cluster calculations have been used to investigate the interaction of SO(2) with defect-free TiO(2)(110) and Ti(2)O(3)(102) surfaces. Adsorbate geometries and chemisorption enthalpies have been computed and discussed. Several local minima have been found for TiO(2)(110), but only one seems…
In this paper, for the first time, we study the properties of a superconductive-based left-handed transmission line (SLHTL). The effect of the kinetic inductance on the propagation constant of the left-handed transmission line is analyzed. It is shown that increasing the kinetic inductance decreases both the bragg fre…
Realizou-se o inventário florístico das diatomáceas pertencentes às classes Coscinodiscophyceae e Fragilariophyceae de rios da bacia hidrográfica Litorânea do Paraná. Amostras planctônicas e perifíticas foram coletadas em dezembro/1998, e em fevereiro e julho/2000 em nove rios: Iporanga, Nhundiaquara, do Nunes, Cachoe…
The electrochemical potentiokinetic reactivation (EPR) test is commonly used to evaluate the degree of sensitization of austenitic stainless steels. It is shown in this study that the EPR test can be used to distinguish between classical sensitization, i.e., chromium depletion formation resulting from the precipitatio…
The effect of strontium doping in K 0.5 Na 0.5 NbO 3 (KNN) ceramics in the amount of 0.5, 2, 5 and 10 atom % is studied. With increasing dopant content the orthorhombic distortion of the perovskite solid solution is markedly reduced. The density of stoichiometric KNN sintered at 1115°C is 94.4% of TD, doping with 0.5%…
Abstract Copper deposition into ordered macroporous silicon prepared in p‐type substrates was investigated by immersion plating and electrochemical deposition in an aqueous solution containing Cu 2+ ions. When the sample was immersed in 0.1 M CuSO 4 solution at the open circuit potential, Cu crystallites are clearly o…
Silk has a long history of use in medicine as sutures. To address the requirements of a mechanically robust and biocompatible material, basic research to clarify the role of repeated sequences in silk fibroin in its structures and properties seems important as well as the development of a processing technique suitable…