Materials Literature
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The mosaic of photoreceptors is regarded as a prime example of the precise control of cellular positioning in the vertebrate nervous system. This study was undertaken with the idea that understanding the intrinsic geometrical features of photoreceptor mosaics is a necessary step to unveil the biological mechanisms gov…
Highly textured mullite was obtained by enhancing anisotropic grain growth by TiO 2 doping and by templating grain growth on oriented acicular mullite seed particles in a mullite precursor. Upon heating, the mullite precursor crystallized and densified to an equiaxed microstructure of 1‐2 µm mullite grains at which ti…
Phase diagrams on the α′‐SiAlON plane have been investigated for ytterbium‐, yttrium‐, and neodymium‐containing systems at different temperatures. Phase relationships between α′‐SiAlON, β′‐SiAlON, AlN polytypoids, and liquid/grain‐boundary phases have been determined. The stability region of the α′‐SiAlON phase increa…
Superfast densification of ceramic composites in the pseudobinary system Al 2 O 3 ‐Y 3 Al 5 O 12 was carried out by using a new technique called spark plasma sintering (SPS). Dense ceramic composites were obtained by heating appropriate powder mixtures to 1573 K in an SPS unit at a rate of 600 K/min. No holding time a…
Spatial confinement on a nm scale can affect molecular dynamics changing form, strength, and frequency of relaxation processes. Dielectric spectroscopy can reveal confinement effects, however, an effective medium analysis has to remove the effects of dielectric heterogeneity. Depending on the microstructure they cause…
In this paper, the theory of lattice dynamics of single-walled carbon nanotubes is presented. The screw symmetry of the system is used to reduce the rank of the dynamical matrix to six, independent of the number of atoms in the unit cell. Calculations of the lattice dynamics are carried out within a valence force fiel…
Bright blue light with a maximum at 450 nm is emitted by both structural isomers of the novel, stable BIII2(O)(7-azain)2Ph2 (7-azain=7-azaindole anion) on irradiation with UV light. The isomer shown in the picture has approximate C2 symmetry (the other isomer approximate Cs symmetry) and electroluminesces when used as…
Polarized hyper-Rayleigh scattering (HRS) has been used to interrogate a putative octupolar “super” chromophore Ru( trans -4,4‘-diethylaminostyryl-2,2‘-bipyridine) 3 2+ . While the hyperpolarizability (β) is impressive, it is apparent from polarized HRS measurements that the symmetry of the excited state, and thus the…
Octasilasesquioxanes are cube-shaped molecules consisting of a Si 8 O 12 core and eight reactive sites, which can, in principle, all be functionalized differently. This review article provides an overview of the work, which is concerned with the monosubstituted species, R′R 7 Si 8 O 12 , where R′ and R are two differe…
Phosphorescence quenching of the porphyrin core by O2 has been studied in a series of dendritic polyglutamic porphyrins. As the generation number increases, in water the dendritic ligands make it increasingly difficult for oxygen to reach the Pd–porphyrin core (figure); they provide no protection in DMF, since there t…
Eine einzigartige Kombination von genau definierter Partikelstruktur und sehr hoher Oberflächenfunktionalität bieten die zur Zeit sehr aktuellen Dendrimere. Das Ziel vieler Arbeitsgruppen, die sich mit dieser ungewöhnlichen Molekülarchitektur beschäftigen, ist die Entwicklung neuer Anwendungen. In dieser Hinsicht am w…
We report field emission microscopy images from single walled carbon nanotubes showing resolvable fine structure with five- and six-fold symmetry. We present evidence indicating that these images have atomic resolution and that they depict the electronic structure of individual nanotube caps under high-field condition…
Optical excitation spectra of the ${\mathrm{Eu}}^{3+}{:\mathrm{Y}\mathrm{A}\mathrm{l}\mathrm{O}}_{3}$ ${}^{7}{\stackrel{\ensuremath{\rightarrow}}{{F}_{0}}}^{5}{D}_{0}$ transition were obtained for ${\mathrm{Eu}}^{3+}$ (0.1, 0.01, 0.001 mol %) at about 2 K. Optical excitation spectra showed more than 60 weak satellite…
Calcite is a common mineral phase found in pure and mixed phase systems. The data reported here was collected for comparison with data collected on other systems and to determine the relative sensitivity for various Ca photopeaks that we were using for the analysis of other Ca-containing mineral phases. This data was…
The automotive industry more and more frequently uses composite materials such as molded compounds (sheet-molded compounds, SMC, or bulk-molded compounds, BMC). Bonding is then the only way of assembling two pieces. Consequently, and in order tentatively to predict the adhesive behavior of such materials, it is necess…
In this paper, the general phenomenological life model proposed by the author for insulating materials with both a threshold or non-threshold behaviour, is applied to experimental data pertinent to two insulating materials for power cables. The first material, EPR, was found to be a non-threshold material for stresses…
The catalytic methanation of carbon dioxide is currently used exculusively in combination with the methanation of carbon monoxide: The synthesis gas for the production of ammonia is purified by simultaneous methanation of carbon dioxide and carbon monoxide, which are catalyst poisons in the ammonia synthesis, down to…
Room temperature X-ray photoelectron spectroscopy (XPS or ESCA) has been employed to investigate pure single crystals of yttrium aluminum perovskite (YAlO 3 (YAP)) and YAlO 3 doped with several rare earth elements, Y 1 - x Ln x AlO 3 (Ln = Pr, Er, Ho). XPS peak shapes of the main elements forming the YAP structure, in…
ABSTRACT A method was developed to characterize visual electrode corrosion during ohmic heating of a model system. Stainless steel 304 electrodes were energized in a 2% salt solution at room temperature of 24±1C for 10 min. The effects of Alternating Current (AC) electrical frequency and current density were examined…
Mercerisation changes the fine structure, morphology and conformation of cotton cellulose chains (cellulose I to cellulose II), resulting in a variation in fibre strength and lustre as well as adsorption properties. Recently it has been shown that mercerisation also changes the electrokinetic behaviour of cotton. The…