Materials Literature
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The crystal structure of [(C5H4BMe2)2Fe]-4,4′-bipyridine [2 · bipy]n has been determined by the method of simulated annealing from high resolution X-ray powder diffraction at room temperature. The compound is of interest, because it proves that highly ordered organometallic macromolecules can be formed in the solid st…
We investigate long-time translational and rotational self-diffusion of fluorocarbon tracer spheres (100 nm radius) in aqueous dispersions of silica host spheres (10 nm radius). Diffusion is measured as a function of ionic strength (0−10 mM NaCl) and for host-sphere volume fractions up to 37% using depolarized dynamic…
The rate of polypeptide chain elongation is up to one order of magnitude faster in prokaryotic cells than in eukaryotes. Here we report that the rates of in vitro refolding of orthologous prokaryotic and eukaryotic proteins correlate with their differential rates of biosynthesis. The mitochondrial and cytosolic aspart…
We have examined the nanomechanics of a carbon nanotube by a manipulation technique using a scanning electron microscope. Young's modulus of the nanotube, estimated from the buckling under force acting on the axial direction of the nanotube, agrees well with the value estimated from the bending under force acting on t…
The potential of porphyrins and related macrocycles for applications in molecular electronics owes much to the fundamental studies of the photosynthetic light-harvesting arrays and reaction centers. The use of model systems to better understand these essential processes has resulted in the development of an assortment…
Since a few years Mg alloys see a renaissance as light-weight materials for automobiles. In cars the Mg-alloys have to withstand elevated temperatures. Under these conditions the time dependence of the deformation of Mg-alloys must no longer be neglected. Therefore a basic research program was started in cooperation w…
Next generation microelectronic packaging requirements are driving the need to produce increasingly lower dielectric constant materials while maintaining high thermal stability and ease of processing. Efforts have focused on the synthesis and analysis of new polymers with the goals of high thermal stability [degradati…
In 1991 Sumio Iijima used a high-resolunon transmission electron microscope to study the soot created in an electrical discharge between two carbon electrodes at the NEC Fundamental Research Laboratory in Tsukuba, Japan. He found that the soot contained structures that consisted of several concentric tubes of carbon,…
The redox chemistry of Co ions in cavities of zeolite MFI has been studied in materials prepared by solid-state ion exchange and displaying Co/Al ratios varying from 0.4 to 1.0. Fourier Transform Infrared (FTIR) spectroscopy, electron spin resonance (ESR), and diffuse reflectance UV−visible spectroscopy were used to i…
A ferroelectric superlattice consisting of two ferroelectric materials is investigated based on the transverse Ising model. We study the effects of long-range coupling interactions on the spontaneous polarization, the Curie temperature, and the dielectric susceptibility of the ferroelectric superlattice. We find that…
The mesopores in silica fibers run in a circular direction around the axis(see Figure), as demonstrated here by examining the optical properties and electron microscopy images of mesoporous silica fibers grown by slow acid synthesis. These fibers are a unique example of a material that is highly ordered on the nanomet…
We report evidence for two distinct strain-induced orientation transitions in a lyotropic bcc cubic crystal submitted to increasing shear rates. The crystal is built up from copolymer spherical micelles in a selective solvent. The distribution of orientations is characterized by x-ray diffraction: in the two oriented…
Abstract The solid state reaction between sodium tri‐titanate and sodium carbonate, forming mainly sodium pentatitanate, was investigated. Experiments were carried out in a micro‐differential reactor made of quartz glass at various temperatures between 800°C and 880°C and in a pilot fluidized bed reactor operated in a…
Precise X-ray powder diffraction data are given for two germanides, CoGe and Co 5 Ge 7 . The refined unit cell parameters for CoGe are a =11.630(1) Å, b =3.8014(3) Å, c =4.9347(3) Å and β=100.889(8)° (space group C 2/ m , Pearson symbol mC 16) with volume of the unit cell 214.24(2) Å 3 ; the figures of merit are M 20…
Microbiologically‐influenced corrosion (MIC) is a type of corrosion in which, by its nature, many uncertainties exist. Using fuzzy logic, two models of MIC are modified to define a fuzzy set of risk of MIC in conditionally‐protected pipes.
Semi-interpenetrating networks of poly(ethylene oxide) (PEO) and highly crosslinked poly(methacrylate)s were generated from solutions of PEO in mixtures of methacrylate monomers and dimethacrylate crosslinkers. The deep quenching of the solutions into the unstable region resulted in microphase separation via a spinoda…
Abstract Cis-trans photoisomerization of azobenzenes in higher concentrations proceeds through a bimolecular reaction process, probably involving the dimer biradical intermediates, in competition with a unimolecular isomerization process, which is the predominant reaction in lower concentrations.
Novel spiro-functionalized polyfluorene derivatives (see Figure) are synthesized here. The absorbance and photoluminescence properties of these compounds are investigated and pure blue electroluminescence is demonstrated in single-layered and double-layered devices. Spiro-functionalization is concluded to be a promisi…
Abstract Microporous materials, (materials with pore sizes with widths <2 nm) were prepared by pillaring of smectites obtained from different soil deposits. The materials were prepared by intercalation with oligomeric cations of aluminum, which were transformed to aluminum-oxide pillars by calcination. The adsorpti…
A new hollandite-type titanate, henrymeyerite, occurs in a vein of tetra-ferriphlogopite ‐ calcite ‐ dolomite carbonatite of the Kovdor alkaline ultramafic complex, Kola Peninsula, in Russia. The mineral was found in a single mineralized vug as acicular crystals less than 0.2 mm in length. The crystals represent a com…