Materials Literature
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Porphyrins and phthalocyanines have now been assembled in a multitude of different architectures, each of which may be identified with a different scenario of the coupling acting between the porphyrins. The synthetic flexibility of these compounds makes possible the design of particular molecules for specific applicat…
The synthesis of refractory Mg‐Al spinel aggregates from bauxites and magnesias was addressed by applying the alumina–magnesia–silica ternary equilibrium phase diagram as the fundamental basis. Four different alumina sources (bauxites) and four different magnesia sources were investigated. These were fired in air thro…
Abstract The program SIR2002 , the heir of SIR2000-N , shows two important new features: a) a figure of merit which is able to recognize the trials potentially able to provide the correct solution; b) a procedure capable of exploiting electron density distributions misplaced with respect to the correct origin. The two…
In the production of cotton and polyester JetRing spun yarns, spindle speed, air pressure, and yarn twist level affect yam hairiness. However, the distance between the front roller nip and the nozzle inlet has only a marginal effect on yam hairiness. Results also show that JetRing spun yams have a much lower numbers o…
A melt-spun Mg-1.5%wtCa-6wt%Zn alloy was analyzed by means of transmission electron microscopy, energy dispersive X-ray spectroscopy, and scanning transmission electron microscopy. The as-solidified alloy exhibited both spherical matrix precipitates and elongated precipitates at the grain boundaries (grain-boundary fi…
Copper (Cu), despite being an essential micronutrient, may be toxic whenever it occurs in the soil solution at high concentrations. Chemical reactions that control copper availability in the soil–plant system are complex. Copper can be found in both organic and inorganic soil fractions. This work studied Cu adsorption…
The second-harmonic generation (SHG) response of unsubstituted subnaphthalocyanines (SubNcs) has been measured for the first time by electric field-induced second-harmonic generation (EFISH) (1.064 and 1.90 μm) and hyper-Rayleigh scattering (HRS) (1.064 μm) experiments. The quadratic hyperpolarizability derived from t…
The dependence of the elastic moduli of a nanocrystal on its size is investigated theoretically with reference to a two-dimensional single-crystal strip. It is shown that the uncertainty (of a fundamental nature) in the size of a nanocrystal causes the determination of many of its mechanical characteristics to be ambi…
Abstract Some soils from the western Amazon region contain KCl-extractable Al contents 5 to 10 times greater than is typical for highly weathered soils containing predominantly kaolinite and gibbsite. We studied a soil sequence from the Brazilian western Amazon consisting of two Typic Udifluvents on the levee of the J…
Nanosized CoAl 2 O 4 and ZnAl 2 O 4 powders with particle sizes of 67 and 6.5 nm are synthesized under hydrothermal conditions at 245°C for 20 h. The precursors are reacted at different temperatures to provide intermediate phase transformations using X‐ray diffraction (XRD), infrared (IR) spectra, and thermal gravity…
Abstract The weathering of chlorite in hydrothermally-altered basalt was studied with XRD, TEM and electron microprobe to determine the type and orientation of secondary minerals. Optical examination indicated chlorite assemblages to have altered in two distinct microsites: one microsite near micro-fissures traversing…
Abstract Polyvinylidene fluoride (PVDF) membranes were surface‐modified using fluorinated surface‐modifying macromolecules (SMMs) additives. The membranes were prepared using the phase‐inversion method. Two novel SMM formulations were used. The effect of some relevant parameters, such as the solvent evaporation time,…
Abstract For testing the determination of the reactivity of aluminum powders it is proposed to use the following parameters: temperature of the beginning of oxidation, maximal oxidation rate, degree of transformation (degree of oxidation) of aluminum, relative thermal effect. Parameters for an evaluation of the reacti…
Abstract The mechanism of ring‐opening polymerization of some lactones and lactide initiated by lanthanum isopropoxide has been comprehensively investigated. NMR and viscosity analyses demonstrated that three active polymer chains grow per lanthanum atom and that, depending on the coordinating ability of the monomer,…
The XPS spectra of ferric phosphate were collected with a VSW HA150 using monochromatic Al Kα x-radiation. Monochromatic radiation provides a distinct clarity to the rich peak structure in the valence band of ferric phosphate due to the absence of interfering x-ray satellites from the intense O 2s region. The valence…
The crystal structure of citrate synthase from the thermophilic Archaeon Sulfolobus solfataricus (optimum growth temperature = 85 degrees C) has been determined, extending the number of crystal structures of citrate synthase from different organisms to a total of five that span the temperature range over which life ex…
Abstract Standard dry surface modification reactions have been applied to partially deacetylated chitosan without affecting its bulk properties. Chitin, extracted from shells of Penaeus vannamei , yielded chitosan with a degree of acetylation of 70% and molecular weight of 250 000 D. The copolymer consists of ( β ‐(1‐…
A centrifugal casting technique was developed for depositing thin 8‐mol%‐yttrium‐stabilized zirconia (YSZ) electrolyte layers on porous NiO‐YSZ anode substrates. After the bilayers were cosintered at 1400°C, dense pinhole‐free YSZ coatings with thicknesses of ∼25 μm were obtained, while the Ni‐YSZ retained porosity. A…
Abstract The tensile behavior of unfilled and 40 w% talc‐filled polypropylene has been determined at four different temperatures (21.5, 50, 75 and 100°C) and three different strain rates (0.05, 0.5 and 5 min −1 ). Experimental results showed that both unfilled and talc‐filled polypropylenes were sensitive to strain ra…
Abstract Imidization of the precursor of a liquid crystalline polyimide was investigated using modulated differential scanning calorimetry (MDSC), Fourier transform infrared (FTIR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and thermogravimetric analyzer (TGA) coupled to FTIR (TG‐IR). The FTIR study reveale…