Materials Literature
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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…
Conducting microtubules of Polyaniline (PANI) were synthesized for the first time by the “in situ doping polymerization” method in the presence of β-naphthal- enesulfonic acid (NSA) as dopant. Different doping methods, such as “immerse doping” and “grind doping,” and different synthetic conditions, such as molar ratio…
In recent experiments on sodium chloride clusters, structural transitions between nanocrystals with different cuboidal shapes were detected. Here we determine reaction pathways between the low-energy isomers of one of these clusters, ${(\mathrm{NaCl})}_{35}{\mathrm{Cl}}^{\mathrm{\ensuremath{-}}}.$ The key process in t…
Silicon clusters and nanocrystals containing up to several thousand atoms per cluster have been generated by pulsed ${\mathrm{CO}}_{2}$-laser-induced decomposition of ${\mathrm{SiH}}_{4}$ in a flow reactor. By introducing a conical nozzle into the reaction zone, the nascent clusters are extracted into a molecular beam…
When multiple elastic diffraction peaks are obtained from an x-ray or neutron source, data analysis is commonly performed using a Rietveld refinement applied to the entire pattern, rather than simply performing single peak fits. In the simplest case the crystal structure is assumed to be ideal despite the presence of…
Quantitative roughness and microstructural analysis of as-deposited Al films, 0.1–1.0 μm thick, were performed by atomic force microscopy (AFM), one-dimensional power spectral density analysis (1DPSD), transmission electron microscopy, and x-ray pole figure methods. The variation of grain size (d) with thickness (h) i…
Ferromagnetic coupling between metal centers and end-to-end coordination of the azido bridges were found together for the first time in the one-dimensional nickel(II) compound [{Ni(5-methylpyrazole)4(N3)}n](ClO4)n⋅n H2O (1; the structure in the unit cell is shown). The ferromagnetic coupling involving spin canting occ…