Materials Literature
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The mechanisms controlling normal and exaggerated grain growth in lead magnesium niobate–lead titanate (PMN–PT) ceramics have been investigated by varying the PbO‐based liquid‐phase volume fraction from 0.03 to 0.6 and sintering temperature from 900° to 1100°C. There is a transition in matrix grain growth rate and mat…
Galactose mutarotase plays a key role in normal galactose metabolism by catalyzing the interconversion of beta-D-galactose and alpha-D-galactose. Here we describe the three-dimensional architecture of galactose mutarotase from Lactococcus lactis determined to 1.9-A resolution. Each subunit of the dimeric enzyme displa…
The enhanced transmittance matrix approach developed by Moharam et al. [J. Opt. Soc. Am. A 12, 1077 (1995)] is reformulated in a concise and illuminating form in terms of scattering (reflection and transmission) matrices directly. Two equivalent recursive formulations, corresponding to their full- and partial-solution…
Boiling water reactor (BWR) fuel at 56 to 61 GWd/tonne U was pulse irradiated in the Nuclear Safety Research Reactor (NSRR) to investigate fuel behavior under cold startup reactivity-initiated accident conditions. Current Japanese 8 × 8 type Step II BWR fuel from Fukushima Daini Unit 2 was refabricated to short segmen…
Hyperbranched polymers generated from the polymerization of AB 2 -type monomers and trifunctional cores with various reactivities were examined by means of the kinetic theory. The average molecular weight, polydispersity, degree of branching, and structural units of the hyperbranched polymers, which all changed with t…
The nature of oxide phases at metal–oxide interfaces, i.e. of oxide layers in the proximity of a metal surface, is assessed by critically examining the available data in the literature. The data reveal a trend towards the formation of reduced oxide phases with lower oxidation states in the vicinity of the interface wi…
Single-crystal X-ray structure determinations of the complex between the minor-groove binder distamycin and d(GGCCAATTGG) reveal two 1 : 1 binding modes which differ in the orientation of the drug molecule in the minor groove. The two crystals were grown from different crystallization conditions and found to diffract…
Abstract Poly(vinyl chloride) (PVC)–clay nanocomposites were prepared by melt blending using a sodium montmorillonite clay. The nanocomposites were characterized by X‐ray diffraction and transmission electron microscopy techniques. The best description of these materials is as mixed immiscible‐intercalated nanocomposi…
Non-symmetric liquid crystal dimers consist of two different mesogenic units linked through a polymethylene flexible spacer. Our previous studies have shown that dimers containing a cholesteryl moiety as one of the mesogenic groups and a Schiff's base unit as the second, exhibit a rich polymorphism and that several ty…
Proteins of silk fibers are characterized by reiterations of amino acid repeats. Physical properties of the fiber are determined by the amino acid composition, the complexity of repetitive units, and arrangement of these units into higher order arrays. Except for very short motifs of 6-10 residues, the length of repet…
[structure: see text] A versatile stepwise synthetic approach to cofacial bis-porphyrin species with calix[4]arene spacers has been designed. The three examples described demonstrate that the method allows selection, in a tailor-made fashion, of the calix[4]arene conformation, the type of functionalization of the cali…
We show that recent claims of experimental verification of a negative index of refraction in metallic metamaterials, "left-handed" microwave frequencies, are questionable. At these frequencies the imaginary part of the dielectric permittivity is significant or even dominates its real part, and hence the effective medi…
The structure of a new iodate, (LiFe 1/3 )(IO 3 ) 2 , has been determined. The new compound has a hexagonal structure with the lattice parameters a =5.4632(2) Å, c =5.0895(6) Å, Z =1. The density is 4.70 g cm −3 . Rietveld refinement confirms that the compound has a space group of P 6 3 (173). Fe and Li atoms randomly…
The corrosion behaviour of mild steel in 2M hydrochloric acid solution containing various concentrations of condensation products formed from glutaraldehyde + glycine (CP1) and glutaraldehyde + methionine (CP2) has been investigated using weight loss measurement and galvanostatic polarization technique. The percentage…
X-ray diffraction techniques have been applied to study the crystallization of poly(ethylene-2,6-naphthalate), PEN. Uniaxial and biaxial orientation of amorphous cast PEN films resulted in stress-induced crystallization of the triclinic α-PEN polymorph. Annealing of the amorphous PEN samples in the range of 160–240 °C…
The crystallization of a confined short polyethylene chain, n-tetracontane, quenched from the melt has been investigated by a dynamic Monte Carlo method on a high coordination lattice. The periodic boundary conditions force the formation of a free-standing nanofiber exposed to a vacuum. After the deep quench, the nano…
Molecular dynamics simulations were used to model the incorporation of magnesium, cadmium and strontium ions at two stepped (10 1 4) surfaces of the calcium carbonate polymorph calcite. The potential model used in the simulations was derived to reproduce experimental enthalpies of CaCO 3 , MgCO 3 , CdCO 3 and SrCO 3 f…
A condutividade térmica é uma das propriedades físicas mais importantes de um material. A sua determinação experimental apresenta algumas dificuldades e requer alta precisão na determinação dos fatores necessários para o seu cálculo. O método de medida de condutividade térmica para materiais refratários mais usado hoj…
The effect of Ca modification on the corrosion properties of weathering steel was investigated by pH measurement, electrochemical impedance spectroscopy (EIS), and cyclic corrosion testing. The pH measurement and EIS were performed with a thin water film covering the steel. Test results showed that the addition of Ca…
Abstract 9-Arylxanthen-9-ylium (3a–i) and 9-arylthioxanthen-9-ylium (4a,b,e–i) perchlorates [aryl = 2,4,6-(MeO)3C6H2 (a), 2,6-(MeO)2C6H3 (b), 2-MeOC6H4 (c), 4-MeOC6H4 (d), 3-Br-2,6-(MeO)2C6H2 (e), 2,4,6-Me3C6H2 (f), 2-MeC6H4 (g), 4-MeC6H4 (h), C6H5 (i)] were prepared by the reactions of 9-arylxanthen-9-ols or 9-arylth…