Materials Literature
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The growth of epitaxial metal–oxide films on lattice-mismatched metal substrates often results in the formation of unique overlayer structures. In particular, epitaxial chromium oxide films grown on Pt(111) exhibit a p(2×2) symmetry through the first two monolayers of growth which is followed by a (√3×√3)R30° phase th…
In this study we re-examined the inducible cytochrome b558/566 from the archaeon Sulfolobus acidocaldarius (DSM 639), formerly thought to be a component of a terminal oxidase (Becker, M., and Schäfer, G. (1991) FEBS Lett. 291, 331-335). An improved purification method increased the yield of the protein and allowed mor…
The metal dusting resistance of various high alloy steels was tested by exposures of specimens in different surface states at temperatures in the range 500 – 650°C. In addition surface analytical studies (AES) were conducted on the initial stages of oxide formation and the oxide layer after long term exposure under me…
The pyridoxal phosphate-dependent enzyme 1-aminocyclopropane-1-carboxylate synthase (ACS, EC 4.4.1.14) catalyzes the rate-limiting step in the ethylene biosynthetic pathway. ACS shares the conservation of 11 invariant residues with a family of aminotransferases that includes aspartate aminotransferase. Site-directed m…
The magnetoresistances (MR's) and magnetic properties of layered manganese oxides, ${\mathrm{Sr}}_{1.6}{R}_{1.4}{\mathrm{Mn}}_{2}{\mathrm{O}}_{7}$ ($R=\mathrm{L}\mathrm{a},\phantom{\rule{0ex}{0ex}}\mathrm{P}\mathrm{r},\phantom{\rule{0ex}{0ex}}\mathrm{N}\mathrm{d},\phantom{\rule{0ex}{0ex}}\mathrm{G}\mathrm{d}$; $R$-327…
The lysine-oxoglutarate reductase (LOR) domain of the bifunctional enzyme lysine-oxoglutarate reductase-saccharopine dehydrogenase (LOR/SDH) from maize endosperm was shown to be activated by Ca2+, high salt concentration, organic solvents and Mg2+. The Ca2+-dependent enhancement of LOR activity was inhibited by the ca…
The magnetic properties of various ${R}_{6}{\mathrm{Fe}}_{13\ensuremath{-}x}{M}_{1+x}$ compounds $(R=\mathrm{La}$, Nd, Gd, and Dy) crystallizing in the ${\mathrm{La}}_{6}{\mathrm{Co}}_{11}{\mathrm{Ga}}_{3}$ structure have been investigated by magnetic measurements and x-ray diffraction. It is shown that all ${\mathrm{…
Annealing induces significant microstructural changes in β‐Si 3 N 4 ceramics densified with a silica containing additive, as signified by the precipitation of elongated Si 2 N 2 O grains in the fine‐grained β‐Si 3 N 4 matrix, leading to a reinforced structure. The phases and microstructure evolution and the interface…
Iron(II) octaethyltetraazaporphyrin has been discovered to exist as two polymorphs at room temperature, α- and β-Fe(OETAP). This has been established by X-ray powder diffraction and scanning electron microscopy. Both ac and dc SQUID magnetometry show that the α phase is a soft molecular ferromagnet with T Curie = 2.8…
Abstract Quantitative kinetic modeling of the condensation of methylethoxysilanes {(CH 3 ) 4‐ f Si(OC 2 H 5 ) f } of varying functionality ( f ) is needed to engineer inorganic polymers, resins, and ceramics. To that end, a kinetic model that accounts for hydrolysis pseudoequilibrium, nearest‐neighbor substitution eff…
We probe the dynamic structure factor of multiarm star polymer solutions in good solvent above the overlap concentration with photon correlation spectroscopy and NMR. With the aid of a mean-field theoretical approach, which accounts for the interplay between the topologically enhanced osmotic pressure and the arm entr…
An aligned carbon nanotube film was fabricated on the surface of an α-SiC wafer by heating at 1700°C for 30 min. in a vacuum electric furnace due to the decomposition of SiC by selected desorption. It was found to be easy to produce a large-area carbon nanotube film on the SiC substrate. The (0002) lattice distance of…
An extensive analysis of the flow orientation modes of sheared liquid crystalline materials is performed using a complete nonlinear nonequilibrium theory that takes into account short and long range order elasticity and viscous flow effects. It is found that there are two main orientation modes in shear flow: (i) in-p…
A group of 4-[4-(4-n-octyloxybenzoyloxy)benzoyloxy]benzylidenemalonic acid bis(perfluoralkyl) esters and 4-{4-[2,2-bis(n-octyloxycarbonyl)ethenyl]benzoyloxy}benzoic acid 4-perfluoro- alkyloxyphenyl esters with varied lengths of the perfluorinated chains were investigated by X-ray measurements. The liquid crystalline b…
We present molecular-dynamics results for a two-component, two-dimensional Lennard-Jones supercooled liquid near the glass transition. We find that the supercooled liquid is spatially heterogeneous and that there are long-lived clusters whose size distribution satisfies a scaling relation up to a cutoff. The similarit…
Polyfunctional dendrimers are empolyed for the synthesis of multi-arm star-shaped polymers. Terminal allyl groups of a carbosilane dendrimer have been partly extended by hydrosilylation-addition of didecylmethylsilane and partly lithiated by reaction with butyllithium. Due to the peculiar structure of the dendritic po…
We present magnetic torque measurements on the quasi-two-dimensional organic superconductor $\ensuremath{\kappa}$-(BEDT-TTF)${}_{2}\mathrm{Cu}(\mathrm{NCS}{)}_{2}$ at low temperature ${T/T}_{c}\ensuremath{\simeq}0.01$. The irreversible field ${H}_{\mathrm{irr}}$ lies far below the upper critical field ${H}_{c2}$ even…
The pore structure stability of MCM-41 materials upon hydration/dehydration was studied by XRD, 29 Si MAS NMR, and gravimetric adsorption techniques. Results demonstrated that collapses of the pore structure of MCM-41 occurred upon rehydration at room temperature due to the hydrolysis of the bare Si−O−Si(Al) bonds in…
Forty-two years ago, Johannes Georg Bednorz and Karl Alex M̈ller startled the world with their unexpected discovery of superconductivity in layered copper oxide perovskites at temperatures substantially higher than previously thought possible. The history of this breakthrough is well known, and a large number of relat…
Abstract Kinetic studies of the bulk polymerization of methyl methacrylate at high temperature have been carried out first without any additives and then in the presence of 1-Butanethiol as a chain transfer agent. A pressurised dilatometric reactor operating at high temperature is used to determine the time-conversion…