Materials Literature
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Based upon kinetic Monte Carlo simulations of crystallization in a simple polymer model we present a new picture of the mechanism by which the thickness of lamellar polymer crystals is constrained to a value close to the minimum thermodynamically stable thickness, lmin. The free energetic costs of the polymer extendin…
The radiation sensitizer gadolinium(III) texaphyrin 2 (XYTRIN; PCI-0120; Gd−Tex 2+ ) and several other water soluble metallotexaphyrin complexes were prepared and studied using pulse radiolysis. All of the metallotexaphyrins were found to react with solvated electrons and hydroxyl radicals, yielding the corresponding…
The effects of PbO addition on the densification, microstructure, and properties of low‐temperature cofirable Ni‐Cu‐Zn ferrite have been investigated. With a small amount of PbO (0.5–2 wt%) present as a dopant in the Ni‐Cu‐Zn ferrite, the densification rate and final sintered density are greatly increased, but the act…
Außerordentlich stabil sind die monodispersen Edelmetallnanopartikel, die unter Verwendung von Dendrimeren als Templat und Stabilisator hergestellt werden können. Dendrimerumhüllte Pd-Nanopartikel (siehe schematische Darstellung) weisen eine hohe katalytische Aktivität bei der Hydrierung von Alkenen in Wasser auf, wob…
We used atomic force microscopy to examine the phase behavior of thin film mixtures of a symmetric A−B diblock copolymer of degree of polymerization N A - B = 650 with (i) two homopolymers ( N A = 20 and 250) and (ii) a symmetric A−B diblock copolymer ( N A - B = 200). Thin film symmetric diblock copolymers are known…
The three-dimensional structures of pyridoxal 5'-phosphate-type aspartate aminotransferase (AspAT) from Thermus thermophilus HB8 and pyridoxamine 5'-phosphate type one in complex with maleate have been determined by X-ray crystallography at 1.8 and 2.6 A resolution, respectively. The enzyme is a homodimer, and the pol…
Abstract The new mesoporous silica with large pore size, SBA-15, was aluminated through the reaction with aluminum chloride. The present alumination method showed a good control of aluminum content but little influence on the pore structure. Aluminum atoms were incorporated into the framework of SBA-15, which resulted…
The effect of glassy‐phase chemistry, using Y 3 Al 5 O 12 (YAG) and SiO 2 as sintering additives, on the microstructure and mechanical properties of liquid‐phase‐sintered, and subsequently annealed, α‐SiC materials was investigated. The microstructural development of annealed materials was insensitive to changes in gl…
It was shown recently that recombinant Escherichia coli, defective in the beta-oxidation cycle and harboring a medium-chain-length (MCL) poly(3-hydroxyalkanoate) (PHA) polymerase-encoding gene of Pseudomonas, is able to produce MCL PHA from fatty acids but not from sugars or gluconate (S. Langenbach, B. H. A. Rehm, an…
The lysine residue binding with the cofactor pyridoxal 5'-phosphate (PLP) plays an important role in catalysis, such as in the transaldimination and abstraction of alpha-hydrogen from a substrate amino acid in PLP-dependent enzymes. We studied the role of Lys39 of alanine racemase (EC 5.1.1.1) from Bacillus stearother…
Thin films of carbon have been deposited on n-type single-crystal silicon and quartz substrates by simple ion beam sputtering of camphoric carbon, obtained from camphor, a natural source. Optical absorption coefficients of 10 4 –10 5 cm -1 have been obtained for the as-deposited and annealed films and the absorption c…
Scanning force microscopy images of thiol-end-functionalized polystyrene monolayers, end-grafted to gold substrates from good solvent, showed two structural regimes in bad-solvent conditions. At low and moderate grafting densities the experimental results agree with the scaling arguments and can be situated correctly…
Highly ordered anodic porous alumina was used as a mask for a reactive beam etching (RBE) to transform the nanochannel pattern into III-V semiconductors. The alumina mask showed high tolerance to RBE using a Br 2 /N 2 mixed gas system. GaAs and InP nanohole arrays with a high aspect ratio and with diameter uniformity…
Silicon nitride (Si 3 N 4 ) and SiAlONs can be self‐toughened through the growth of elongated β‐Si 3 N 4 /β‐SiAlON grains in sintering. α‐SiAlONs usually retain an equiaxed grain morphology and have a higher hardness but lower toughness than β‐SiAlONs. The present work has demonstrated that elongated alpha‐SiAlON grai…
In order to impart barrier properties against microorganisms and blood to 100% cotton fabrics and 55/45% woodpulp/polyester spunlaced nonwoven fabrics, samples are treated with chitosan and fluoropolymers using the pad-dry-cure and pad-cure meth ods, respectively. Antimicrobial activity of the samples is analyzed quan…
In the framework of recently introduced frustrated lattice gas models, we study the out-of-equilibrium dynamical processes during the compaction in granular media. We find irreversible-reversible cycles in agreement with recent experimental observations, along which we can individuate an equivalent ``glass transition,…
The synthesis, reactivity and full characterization of a series of meso-tetraalkyl porphyrins and metalloporphyrins with R ≡ n-butyl (6), 2-methyl-propyl (7), isopropyl (8), l-ethyl-propyl (10) and tert-butyl (11) groups are reported. Derivatives of the last of these show considerably bathochromically shifted absorpti…
The capitate and rectangular demes of the freshwater epipelic diatom Sellaphora pupula (Kütz.) Mereschk. are dioecious, the first such report for any freshwater diatom. Sexual differentiation, which is probably determined genetically, involves recognition at the cell surface as well as differences in gamete behavior (…
The continuous structural transformation of tetragonal analcime (Na 15.87 Al 15.20 Si 32.64 O 96 ·16.3H 2 O) upon dehydration was studied, using Rietveld structure analysis of temperature- resolved powder diffraction data collected using synchrotron radiation. The variation of the a-c axis length difference and normal…
The mechanical response of a smectic-A liquid-crystalline side-chain polymer network with macroscopically ordered layers (smectic-A liquid single crystal elastomer) to extensive stress applied parallel to the layer normal is described. By stress-strain measurements a characteristic threshold strain of about 3% is obse…