Materials Literature
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The NCOCH2(CF2)6CH2OCN fluoromethylene cyanate ester monomer and resin are synthesized and characterized. The monomer is prepared by a large-scale bench-top synthesis, characterized by differential scanning calorimetry, infrared, 1H-, 13C-, 15N-, and 19F-NMR spectroscopies and analyzed for catalytically active impurit…
Optical excitation of half-leaky guided modes has been used to explore the director distortion of a homogeneously aligned nematic liquid crystal (BDH E7) under application of an in-plane electric field. Homogeneous alignment is realized by obliquely evaporated SiOx layers with an in-plane field being applied across a…
A novel approach for porphyrin modification is provided by ring-enlargement reactions. Treatment of dioxochlorins (see scheme) and tetraoxobacteriochlorins with diazomethane results in formation of the corresponding mono- and di(oxopyri)porphyrins.
Hochreaktiv sind die aus Alkalimetallaziden in situ gebildeten Alkalimetalloxide. Deren Umsetzung zu ternären Oxiden verläuft aber kontrolliert und bietet damit ein elegantes Syntheseverfahren für Alkalimetalloxometallate.
Thermal expansion, magnetization, and electrical-resistivity measurements of single crystalline ${\mathrm{La}}_{0.83}{\mathrm{Sr}}_{0.17}{\mathrm{MnO}}_{3}$ are presented. A first-order structural transition occurs at 300 K, transforming the high-temperature rhombohedral phase into an orthorhombic phase. The paramagne…
The thermal and catalytic degradation of mixed plastics containing poly(vinyl chloride) (PVC) was carried out at 360−430 °C under atmospheric pressure by semibatch operation. The boiling-point distributions of organic chlorine compounds in the oil obtained from the degradation of mixed plastics PE/PVC, PP/PVC, and PS/…
The oxidation kinetics of two kinds of polycrystalline nickel particles with an approximate median diameter of 5 μm but with different morphology, has been studied by thermogravimetric measurements in the temperature range 573–973 K. The oxidation was found to be thermally activated with an apparent activation energy…
Electron paramagnetic resonance (EPR) and photoluminescence (PL) spectroscopy have been used to examine the structure and optical properties of erbium-impurity complexes formed in float-zone Si by multiple-energy implants at 77 K of Er together with either O or F. After implantation a 2-\ensuremath{\mu}m-thick amorpho…
An unprecedented coordination mode for the highly conjugated cyanocarbanion [C{C(CN)2}3]2− (1) is observed in the title complexes. This ligand employs four of its six CN groups in a μ4-η4 bridging mode to form two unique three-dimensional polymers.
We report on structural studies of multiwall carbon nanotubes by wide-angle neutron scattering up to a maximum scattering vector ${Q}_{\mathrm{max}}=166 {\mathrm{nm}}^{\ensuremath{-}1}.$ The derived reduced radial distribution functions of the nanotubes are compared to those determined for graphite and turbostratic ca…
We present fully converged, all-electron, ab initio calculations of the structural relaxation at the ${\mathrm{TiO}}_{2}(100)\ensuremath{-}(1\ifmmode\times\else\texttimes\fi{}1)$ surface. The effects of electron exchange, correlation, and various numerical approximations are isolated and quantified. We find that the p…
Poly(ether ester)s consisting of poly(ethylene oxide) and poly(ethylene terephthalate) segments, EOET copolymers, could be used as shape memory polymers (SMP). Crystalline structural characters of the copolymers during the memory process were investigated by dynamic mechanical analysis, differential scanning calorimet…
Ferromagnetic and antiferromagnetic interactions within and between the chains, respectively, result in metamagnetism in the first one-dimensional coordination polymer to include alternating high-spin (HS; S=2) and low-spin (LS; S=1) MnIII centers bridged by cyano groups, namely, [{Mn(salen)CN}n] (salen=bis(salicylide…
Using nonresonant bond polarization theory, we have calculated the Raman intensity of a single-wall carbon nanotube of finite length. The calculations show that the Raman peaks in the intermediate frequency range $(500--1200{\mathrm{cm}}^{\mathrm{\ensuremath{-}}1})$ have no intensity for infinite nanotubes, but do hav…
We use a transfer-matrix method to study defects in a tight-binding model of carbon nanotubes. We calculate the reflection coefficient R for a simple barrier created by a pointlike defect of strength E in armchair ${(N}_{a}{,N}_{a})$ and zigzag ${(N}_{a},0)$ nanotubes for the whole range of energy $\ensuremath{\omega}…
We have obtained the Mn $3d$ partial density of states in ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ using the resonance photoemission technique as well as by means of the difference between ${\mathrm{Ga}}_{1\ensuremath{-}x}{\mathrm{Mn}}_{x}\mathrm{As}$ and GaAs. We have observed a strong satellite…
The metal ion determines the reactivity upon electrochemical oxidation of metal porphyrins that are unsubstituted at the meso position. Thus, with Cu2+, Pd2+, and Ni+2 as the central ion (and for the free porphyrin base), directly linked meso,β porphyrin dimers 2 were formed, while Mg and Zn complexes afforded the cor…
The density of electron states of nm-size Si particles in ${\mathrm{SiO}}_{2}$ layers produced by implanting ${\mathrm{O}}^{+}$ ions into Si is analyzed using a newly developed total optical depopulation technique. The distribution of states is found to be indistinguishable for neutral and negatively charged particles…
Using the MgO/Ag(100) interface as a model system, we demonstrate that Coulomb and charge-transfer energies in oxide layers deposited on a highly polarizable medium like a metal, are reduced from their bulk values, by as much as 1.8 eV and 2.5 eV, respectively. The use of efficient image potential screening may provid…
${\mathrm{ZrO}}_{2}$ nanograins annealed at different temperatures are systematically investigated using x-ray diffraction (XRD) and Raman spectroscopy. Our results show that bulk properties of nano-${\mathrm{ZrO}}_{2}$ diminish but the defect-, surface-, and size-related features display as grain size decreases. A cr…