Materials Literature
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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…
In situ x-ray diffraction on Pd hydride under 5 GPa of hydrogen pressure show that lattice contraction due to vacancy formation occurs in 2-3 h at 700-800 \ifmmode^\circ\else\textdegree\fi{}C, and two-phase separation into PdH and a vacancy-ordered phase of ${\mathrm{Cu}}_{3}$Au structure (${\mathrm{Pd}}_{3}$${\mathrm…
We propose an extension of the van der Waals equation which is designed to incorporate, in an approximate fashion, the effects of the network of hydrogen bonds that exist in liquid water. The resulting model qualitatively predicts the unique thermodynamic properties of water, including those of the deeply supercooled…
Reversible γ-induced structural transformations in vitreous As2S3 are studied using ESR and differential IR Fourier-spectroscopy techniques. It is shown that the investigated low-temperature (T < 100 K) as well as high-temperature (T ≈ 300 K) radiation-structural transformations are associated with chemical bond break…
A pivotal role in the formation of lactam catenanes is attributed to macromonocycle 1. The synthesis of a monosubstituted catenane, in which 1 acts as host, provides evidence for the proposed mechanism. Three iso-meric disubstituted catenanes are also prepared.
This article describes the use of synchrotron radiation to study chemical and structural changes of catalysts during actual operating conditions. Described are techniques using x-ray absorption near edge structure, extended x-ray absorption fine structure, pre-edge x-ray absorption, and x-ray diffraction. Some of the…
Optical and electrical properties of the gallium telluride Ga2Te3 are reported. Lattice modes are investigated using far-infrared spectroscopy and polarized Raman scattering experiments. The farinfrared reflectivity spectrum which is analyzed using a Lorentzian-oscillator model and the Raman spectrum shows that this c…
Strong through-space interactions with the dendritic shell surrounding the chromophore are at the root of the unusual redox properties of the porphyrin unit in 1. Compound 1, measuring approximately 4 nm in diameter with a molecular weight of over 19 kDa, represents a new class of synthetic, densely packed, globular e…
We review the x-ray-diffraction and high-resolution transmission electron microscopy (HRTEM) data that Doll et al. [Phys. Rev. B 43, 6816 (1991)] used as evidence for the epitaxial growth of cubic boron nitride (cBN) on silicon (001) surfaces. The three reported x-ray-diffraction peaks do not provide unambiguous evide…