Materials Literature
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The projected atomic structure of the $\ensuremath{\alpha}\ensuremath{-}{\mathrm{Al}}_{2}{\mathrm{O}}_{3}(0001)(\sqrt{31}\ifmmode\times\else\texttimes\fi{}\sqrt{31})R\ifmmode\pm\else\textpm\fi{}9\ifmmode^\circ\else\textdegree\fi{}$ reconstruction has been analyzed by means of the grazing incidence x-ray diffraction te…
Raman scattering has been used to measure phonon linewidths and frequencies of a number of high quality diamond crystals. It was found that the defect induced broadening produced a Lorentzian line shape. The smallest Lorentzian linewidth of 1.68 cm−1 at 300 K caused by anharmonicity and defects was obtained for the hi…
The magnetic susceptibility of the tungsten intermediary oxides WO 3-x (0.05<or=x<or=0.28) with the crystal shear and pentagonal column structures was measured using the Faraday method. A feeble temperature-independent paramagnetic component chi (e) of the total susceptibility was present in each case. Using the Pauli…
Abstract A series of polyurethane elastomers with different hard‐segment contents of 24% (M24), 34% (M34), 50% (M50), and 100% (M100) have been investigated through thermogravimetric analysis (TGA) measurement and mathematical simulation. The fourth‐order Runge–Kutta method was used to solve the differential equations…
The wetting and capillarity of carbon nanotubes were studied in detail here. Nanotubes are not "super-straws," although they can be wet and filled by substances having low surface tension, such as sulfur, selenium, and cesium, with an upper limit to this tension less than 200 millinewtons per meter. This limit implies…
Abstract Cyclo(‐ D ‐Leu‐ L ‐MeLeu‐ D ‐Leu‐ L ‐MeLeu‐ D ‐Leu‐ L ‐MeLeu‐) ( 1 ) and cyclo(‐ L ‐Leu‐ D ‐Leu‐ L ‐MeLeu‐ D ‐Leu‐ L ‐Leu‐ D ‐Leu‐) ( 2 ) were synthesized and used for a study of the interaction of β ‐rings in solution. In appropriate solvents, 1 and 2 formed dimers consisting of two β ‐rings connected throug…
Abstract ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” opt…
A detailed physico-chemical analysis of two foaming fungal fermentations was carried out to identify that key groups of compounds responsible for foam formation. Fermentations were carried out on a 20-L scale in a stirred aerated tank, over 7 days, using a commercial, defined medium. The organisms investigated were Pe…
We have used telluride glass fibers fabricated in house to measure the evanescent-absorption spectra of water, methanol, ethanol, isopropanol, acetone, ethanoic acid, hexane, and chloroform. Furthermore, detection limits of less than 2 vol. % solute were obtained for mixtures of water and methanol, ethanol, isopropano…
Abstract Microporous polypropylene hollow fibers were prepared by stretching polypropylene microtubes containing poly(methylsilsesquioxane) fillers with uniform particle sizes. The properties of the resultant hollow fibers are controllable by adjusting the particle size of the filler, the filler content, and the stret…
Abstract A diblock copolymer, i.e., poly(isobutyl vinyl ether)‐ b ‐poly[2‐(vinyloxy)ethyl cinnamate] (PIBVE‐ b ‐PVEC), has been shown to form polymer brushes quickly on the surface of solid substrates by deposition from a solvent selectively poor for PVEC. The resultant brush could be cross‐linked photochemically by i…
Locations and assignments of crystal-field levels in polarized absorption spectra (77 and 298 K) are reported for Eu 3+ in the GdAl 3 (BO 3 ) 4 huntite matrix. The levels are analysed in terms of 20 free-ion and six crystal-field parameters (D 3 symmetry). J mixing is taken into account. The influence of a parameter c…
Abstract The hydrolytic degradation of gel microspheres based on calcium cross‐linked phosphazene polyelectrolytes, poly[di(carboxylatophenoxy)phosphazene] (PCPP) and poly[(carboxylatophenoxy) (glycinato)phosphazene] (PCGPP), was investigated. These microspheres are of importance as carriers in protein and cell encaps…
The first-principles method for calculating the elastic stiffness tensor of composite crystals has been given. Applying the present method to the wurtzite and rocksalt structures of AlN under normal and elevated pressure up to 25.8 GPa, we have determined the elastic stiffness tensor completely from first principles.…
We report electroluminescence from a regioregular alkyl-phenyl substituted polythiophene. The polymer film exists in two forms, giving widely different optical absorption, as well as photoluminescence and electroluminescence spectra. In the low-bandgap form, we observe high emission intensity centered at 1.55 eV (800…
In the primary soot produced by arc discharge using an yttrium carbide loaded anode, bundles of single-walled carbon nanotubes (SWT) are observed, protruding radially from YC2 particles coated with graphitic multilayers. The graphitic cages separating YC2 particle and SWT bundles fall into the narrow range of 10–20 la…
Building on analogies with low work function metal surfaces, an oxygenated C(100) surface cesiated at the half-monolayer level has been studied with self-consistent local-density-based methods. Cesiation of the surface is found to shift the 2.45 eV positive electron affinity oxygenated surface to a surface with the bu…
It is shown that the green/blue luminescence which is found in oxidized nanocrystalline and ‘‘porous’’ silicon is associated with the presence of OH groups adsorbed on structural defects in the SiO2 network.
The development of ferroelectric memory devices requires an improvement of the fatigue properties of ferroelectric thin films. Pb(Zr,Ti)O3(PZT) thin films obtained by the sol-gel method on Pt/Ti electrodes have reduced residual polarization by continuous polarization reverses about of 108 cycles. The electric characte…
Enhancement mode-type metal-semiconductor field effect transistors using diamond have been fabricated. The transistor operation is based on the control of surface p-type conduction of a hydrogen terminated homoepitaxial layer. Boron doping was not used for the conduction. An aluminum contact is used for the Schottky g…