Materials Literature
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We report a systematic study of the microstructure and dielectric properties of barium strontium titanate, Ba1−xSrxTiO3, films grown by laser ablation on LaAlO3 substrates, where x=0.1–0.9 at an interval of 0.1. X-ray diffraction analysis shows that when x<0.4, the longest unit-cell axis is parallel to the plan…
A grain-size-dependent reduction in the room-temperature thermal conductivity of nanocrystalline yttria-stabilized zirconia is reported for the first time. Films were grown by metal-organic chemical vapor deposition with controlled grain sizes from 10 to 100 nm. For grain sizes smaller than approximately 30 nm, a subs…
The first measurements of the tensile elastic modulus of polypyrrole nanotubes are presented. The nanotubes were mechanically tested in three points bending using atomic force microscopy. The elastic tensile modulus was deduced from force-curve measurements on different nanotubes with outer diameter ranging between 35…
Using one- and two-dimensional NMR spectroscopy applied to 13C spin-labeled (TMTTF)2AsF6 and (TMTTF)2PF6, we demonstrate the existence of an intermediate charge-ordered phase in the TMTTF family of charge-transfer salts. At ambient temperature, the spectra are characteristic of nuclei in equivalent molecules. Below a…
The electronic structure of Ge nanocrystals is studied using a sp3 tight binding description. Analytical laws for the confinement energies, valid over the whole range of sizes, are derived. We validate our results with ab initio calculations in the local density approximation for smaller clusters. Comparing to experim…
The effect of oxygenation on the electronic properties of semiconducting carbon nanotubes is studied from first principles. The O2 is found to bind to a single-walled nanotube with an adsorption energy of about 0.25 eV and to dope semiconducting nanotubes with hole carriers. Weak hybridization between carbon and oxyge…
The high-temperature (beta-) modification of Hg2MoO4 was prepared by solid-state reaction of HgO with MoO2 at 400 degrees C. Well-crystallized samples of the low-temperature (alpha-) modification of Hg2MoO4 and isotypic Hg2WO4 were obtained by hydrothermal recrystallization of the microcrystalline powders at 180 degre…
Spicule matrix proteins are the products of primary mesenchyme cells, and are present in calcite spicules of the sea urchin embryo. To study their possible roles in skeletal morphogenesis, monoclonal antibodies against SM50, SM30 and another spicule matrix protein (29 kDa) were obtained. The distribution of these prot…
Electron paramagnetic resonance (EPR) spectroscopy was used to investigate adsorption of a series of amines (ammonia, methylamine, triethylamine) on Cu−ZSM5 and Cu−Beta. Several changes were observed in the EPR spectra after adsorption of the amine: an increase in spectral broadening, a shift in the copper hyperfine f…
The reaction of NO with char-bound nitrogen was studied using four model structures to represent the nitrogen left with the char when coal is devolatilized. The calculations were carried out to simulate combustion conditions resulting in the absence and presence of preadsorbed oxygen on the char. Density Functional th…
Many analytical techniques, such as differential scanning calorimetry (DSC), X-ray diffraction (XRD), infrared spectroscopy (IR) and Raman spectroscopy can be used to differentiate between crystalline polymorphs of the same chemical entity. While all of these techniques are routinely applied to off-line analysis of ma…
The thermodynamic potential of ideal gases described by the simplest non-abelian statistics is investigated. I show that the potential is the linear function of the element of the abelian-part statistics matrix. Thus, the factorizable property in the Haldane (abelian) fractional exclusion shown by the author [W. H. Hu…
A new terephthalate-based cobalt hydroxide, Co 2 (OH) 2 (C 8 H 4 O 4 ), was synthesized by the hydrothermal method. Its crystal structure has been determined by ab-initio XRPD methods (monoclinic, C 2/ m, a = 19.943(1), b = 3.2895(1), c = 6.2896(3) Å, β = 95.746(3)°) and fully refined by the Rietveld technique down to…
The aggregation of Au nanoparticles in solution is induced and influenced by cationic and oligocationic species. This solution-state aggregation bears similarities to multilayer formation on surfaces but is more facile because of the nanoparticles' intrinsic instability in solution. Aggregation is followed by transmis…
Das aus NO und NO2 gebildete N2O3 konkurriert mit Wassermolekülen um Koordinationsstellen der Natrium-Wasser-Netze in den Superkäfigen von Zeolith Na-Y. Infolgedessen ist die NOx-Adsorption durch diesen Zeolithen (siehe Bild) reversibel. Sie ist darüber hinaus unempfindlich gegenüber SO2 und bietet somit eine echte Al…
Enge Bandlücken und hohe Elektronenaffinitäten zeichnen konjugierte Oligomere aus, die Thiophen-1-oxid- und Thiophen-1,1-dioxid-Einheiten enthalten und durch Zirconocen-vermittelte Kupplungsreaktionen synthetisiert wurden. Eine Reihe von Oligomeren mit drei bis elf Ringen (X=2 H, S=O, S(=O)2; siehe Bild) ermöglichte e…
N,N'-Bis(2-propenyl)-2,7-diazapyrenium salts are synthesized in good yield from the reaction of 1,4,5,8-naphthalenetetracarboxylic dianhydride with allylamine, followed by LiAlH(4) reduction and subsequent oxidation with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). The nature of the counteranion depends on the sol…
The stretching-induced alpha−beta polymorphic transition in the crystalline regions of poly(butylene terephthalate) (PBT) is studied by small-angle X-ray scattering (SAXS), instead of by the wide-angle X-ray scattering (WAXS) usually used for this purpose. An expression for the increase of the long spacing upon the tr…
A Cayley tree is the structural motif of the dendrimerlike supramolecular structure that is formed by self-assembly of the bile salt sodium deoxycholate (NaDC) with the β-cyclodextrin trimer T (see schematic picture). This is the first example of dendritic growth by a cyclodextrin complex.
Optical components, such as miniature spectrometer gratings working in the infrared range for environmental monitoring or physical analytics, contribute appeciably to the price of Micro Electro Opto Mechanical Systems (MOEMS). These optical components could be a part of a miniature functional package produced with an…