Materials Literature
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Addition of Bi prevents deactivation of Pd–Sb catalysts in the acetoxylation of toluene. The presence of Bi hinders the formation of an inactive Pdδ− state and the blockage of the active Pd sites by carbon species from coke deposits (see the photoelectron spectrum). The modified catalyst displays extremely high select…
A high creep resistance at specified temperature and compressive stress was obtained in this investigation in the silicon nitride/silicon carbide composite with a nano–nano structure (nanosized SiC and Si 3 N 4 in dual‐phase mixture) by a novel synthesis method. Starting from an amorphous Si–C–N powder derived from py…
Abstract Biodegradable poly( L ‐lactide‐ co ‐ε‐caprolactone) copolymers with different L ‐lactide (LLA)/ε‐caprolactone (CL) ratios of 75/25 and 50/50 were electrospun into fine fibers. The deformation behavior of the electrospun membranes with randomly oriented structures was evaluated under uniaxial tensile loading.…
Sr 1− x Ba x Bi 2 Nb 2 O 9 ( x =0, 0.2, 0.4, 0.6, 0.8 and 1) ceramics were prepared by a conventional solid‐state reaction method. Their structure and dielectric properties were investigated. X‐ray diffraction analysis indicated that single‐phase layered perovskites were obtained. A relaxor behavior was observed in Ba…
Three dodecanuclear Mn clusters [Mn12O10(OMe)3(OH)(O2CC6H3F2)16(MeOH)2].8MeOH (1), [Mn12O10(OMe)4(O2CBu(t))16(MeOH)2] (2), and [Mn12O12(O2CBu(t))16(MeOH)4] (3) synthesized by reductive aggregation reactions are reported. Clusters 1 and 2 possess a central alkoxide-bridged planar Mn4 topology, whereas 3 is a new high-s…
We have synthesized an amphiphilic triblock coil-rod-coil molecule consisting of a rigid aromatic building block and poly(ethylene oxide). The coil-rod-coil molecule was observed to assemble into a cylindrical micelle structure in aqueous solution. Notably, addition of a small amount of a rod-coil-rod molecule into th…
The prime objective of this work is to demonstrate that chromium‐doped alumina fibers could, for the first time, be obtained via vapor liquid solid (VLS) deposition. Various procedures are described and discussed in the text. The mechanism for effective doping is also discussed, and the resulting fibers are analyzed.…
The structural, electronic, and the bonding properties of the zeolite Sn-beta (Sn-BEA) have been investigated by using the periodic density functional theory. Each of the nine different T-sites in BEA were substituted by Sn atoms and all the nine geometries were completely optimized by using the plane-wave basis set i…
The first chiral molecular hybrids based on covalently linked polyoxometalate clusters and enantiopure 1,1'-binaphthyl units have been prepared. Their structures have been confirmed by (1)H NMR, FTIR, and ESI-MS measurements. Such hybrids show moderate chiroptical behavior in solutions, and Cotton effects are observed…
Nanorods of nickel and copper oxalate have been synthesized by the reverse micellar route. Powder X-ray diffraction studies and thermo gravimetric analysis confirms the formation of monophasic NiC2O4 x 2H2O and CuC2O4 x H2O. Transmission electron microscopy shows that the as prepared nanorods of nickel and copper have…
The surface acidity of different mesoporous titanium-silicates, such as well-organized hexagonally packed Ti-MMM, Ti-MMM-2, Ti-SBA-15, and amorphous TiO(2)-SiO(2) mixed oxides (aerogels and xerogels), was studied by means of FTIR spectroscopy of CO adsorbed at 80 K and CD(3)CN adsorbed at 293 K. The surface hydroxyl g…
Abstract Segmented polyurethanes were prepared from soy polyol, diphenyl methane diisocyanate (MDI), and ethylene glycol or butane diol as chain extenders. Samples were prepared with true hard‐segment concentrations (HSC) of about 0, 10, and 40%. Both the soft MDI–polyol and hard MDI/diol segments are glassy at room t…
When a 2,5-diamino-1,4-benzoquinonediimine C6H2(=NR)2(NHR)2 (2) is used as a bridging ligand, new dinickel(II) complexes [(acac)Ni[mu-C6H2(=NPh)4]Ni(acac)] (3a: R=Ph) and [(acac)Ni[mu-C6H2(=NCH2tBu)4]Ni(acac)] (3b: R=CH2tBu) are obtained; upon one-electron oxidation of these complexes delocalized mixed-valence compoun…
Solid oxide fuel cells (SOFCs) are advancing steadily as materials become more widely available, as cell stacking techniques develop, as operational issues such as rapid start-up are addressed and as applications become more focused. The present study reviews recent developments in SOFC materials, positioning them in…
Using transmission electron microscopy, we identify the temperature-dependent interaction pathway of carbon-supported Au nanoparticles. At low temperature (room temp. to 400 degrees C), Au nanoparticles predominantly interact by coalescence initiated by an atomic Au bridge. At high temperature (400-800 degrees C), the…
Collagen (type I from calf skin) adsorption on polystyrene (PS) and plasma-oxidized polystyrene (PSox) was studied, using a quartz crystal microbalance with energy dissipation measurements (QCM-D) and atomic force microscopy (AFM) in tapping mode. Radio-labeled collagen was used to measure the adsorbed amount and the…
We developed a straightforward method to produce hexagonal ZnO nanorods and microrods using a novel biocatalyst, Magnetospirillum magnetotacticum. ZnO nanorods were synthesized homogeneously on growth substrates when the bacterial catalysts were deposited uniformly on substrates whereas ZnO microrods were formed when…
Suspensions of binary mixtures of hard-sphere poly-methylmethacrylate colloidal particles were studied at six different size ratios alpha. The main aim was to determine the range of size ratios over which the binary colloidal crystals AB2 and AB13 are stable. Combining these results with those of earlier work, we foun…
Bulk modification of polypyrrole (PPY) with poly(vinyl alcohol) (PVA) was carried out by the electropolymerization of pyrrole in the presence of PVA in the reaction solution, with tetraethylammonium perchlorate (TEAP) as the electrolyte. The surface morphology of the as-synthesized PPY-TEAP-PVA film was investigated u…
Herein is reported a metamorphosis taking place in a gold nanosized system. The observed phenomenon of shape and size transformations was found to be completely reversible. Unlike most procedures in the literature where shape and size control occur in the synthetic step by adding growth- and shape-controlling agents s…