The Redox Chemistry of Metallophthalocyanines in Solution
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Charge-density-wave phase slip and current conversion inNbSe3
We report measurements of the phase-slip process by which charge-density-wave (CDW) current is converted to single-particle current at electrical contacts. An excess voltage ${\mathit{V}}_{\mathrm{ps}}$ produces a large static deformation of the CDW phase, which drives formation of dislocation loops. Measurements of t…
Visible electroluminescence from porous silicon np heterojunction diodes
We report the preparation of silicon-based visible light-emitting diodes, configured as heterojunctions between porous silicon (formed by electrochemical etching of p-type silicon wafers), and n-type indium tin oxide (ITO). The transparent ITO film allows light emission through the top surface of the device, under a f…
Ion transport anomalies in glasses
A model for ion transport in glass is presented which is based on the experimental evidence that cations in glass create and maintain their own characteristic environments. By postulating the existence of a site memory effect, we are able to visualize the formation of conducting pathways. We develop a quantitative the…
Modification of chlorinated poly(vinyl chloride) by blending with epoxidized polybutadiene
Abstract The compatibility of epoxidized poly( cis ‐1,4‐butadiene) (EPB) with chlorinated polyvinylchloride (CPVC) was investigated. Blends studied covered the complete composition range using EPB at two degrees of epoxidation: 20 and 43 mol % oxirane units. Tensile properties of EPB (63)/CPVC were also studied at the…
Computational study of tetragonal B50N2
We find that tetragonal B${}_{5}$${}_{0}$N${}_{2}$ is stable against decomposition into BN and B${}_{1}$${}_{2}$, that the calculated lattice constants are in excellent agreement with the x-ray data, and that the atomic positions within the unit cell agree in general with the x-ray data but differ in detail due to dis…
Fracture studies of diamond films on silicon
Diamond coatings were prepared on silicon substrates for fracture studies. Two thicknesses of coatings were evaluated: 6 and 12 μm. The diamond films increased the strength of the silicon for the same size fracture initiating crack and thus caused an apparent toughness increase from 1.2 MPam1/2 for the uncoated silico…
TE and TM modes in a cylindrical liquid-crystal waveguide
We consider a cylindrical waveguide consisting of an inhomogeneous anisotropic liquid-crystal core embedded in an infinite homogeneous isotropic cladding. The wave equations for the pure modes are uncoupled but may have complex coefficients owing to the inhomogeneity and anisotropy of the liquid crystal. A simple nume…
Correlated-barrier hopping in semiconducting tellurium molybdate glass
Measurements are reported for the real and imaginary parts of the ac conductivity of semiconducting tellurium molybdate glass in the frequency range ${10}^{2}$--${10}^{5}$ Hz and in the temperature range 80--350 K. The experimental results are interpreted in terms of the classical correlated-barrier hopping theory.
Bundles: End-Grafted Polymer Layers in Poor Solvent
The structure factor for a system of end-grafted neutral polymers is computed self-consistently in a random phase approximation. Both single-end-grafted, brushes, and twice-grafted layer are considered. We find that the polymer brush collapses uniformly, density variations in the direction parallel to the grafting pla…
Molecular orientation of vacuum-deposited thin films of zincnaphthalocyanine
Zinc 2,3-naphthalocyanine (ZnNc) was vacuum evaporated onto glass, NaCl, and highly oriented pyrolytic graphite (HOPG) substrates, and the molecular orientation was investigated by x-ray-diffraction, Fourier-transform-infrared–reflection-absorption spectroscopy, electronic spectroscopy, transmission electron microscop…
Self-consistent dc glow-discharge simulations applied to diamond film deposition reactors
Self-consistent particle-fluid hybrid simulations have been used to study the structure of hydrogen dc discharges between parallel plates. A Monte Carlo simulation is used to describe individual energetic electrons in the cathode sheath, while the electrons and ions in the low-field region of the discharge are modeled…
Preparation of aminoalkyl celluloses and their adsorption and desorption of heavy metal ions
Abstract Aminoalkyl celluloses (AmACs) were prepared from 6‐chlorodeoxycellulose and aliphatic diamines H 2 N(CH 2 ) m NH 2 (m = 2, 4, 6, 8). Their adsorption and desorption of divalent heavy metal ions such as Cu 2+ , Mn 2+ , Co 2+ , Ni 2+ and their mixtures were also investigated in detail. Adsorption of metal ions…
Exponential Growth of Fingering Instabilities of Spreading Films Under Horizontal Thermal Gradients
A thin liquid ribbon deposited on a wettable surface and subjected to a horizontal thermal gradient develops periodic fingers towards the cold region. We present an observation of the exponential growth regime, expected at early times, but not accessible in other driven fingering patterns induced by gravitational flow…
Shock and release wave properties of yttria-doped tetragonal and cubic zirconia
Velocity interferometry diagnostics are used to monitor transmitted compressive shock and release waves in yttria (Y2O3)-stabilized tetragonal and cubic zirconia. In tetragonal zirconia compressive yielding due to lattice slip or lattice instability is observed at 13–17 GPa and again at 30–31 GPa. This represents an a…
Phonon modes in graphite,C60, andC60-based fibers
The influence of curvature on the radial vibrational modes in ${\mathrm{C}}_{60}$ and ${\mathrm{C}}_{60}$-based fibers is considered and is shown to lead to a softening of these modes in comparison with the out-of-plane phonon mode in graphite. The effect on the restoring force constants of doping these systems with a…
Sensitivity of optical-absorption intensities for rare-earth ions
A technique is presented that uses molecular-dynamics simulation to generate the atomic positions needed to calculate the crystal-field parameters used in a Judd-Ofelt (JO) analysis. A slightly modified theory is used that permits analysis of both \ensuremath{\pi}- and \ensuremath{\sigma}-polarized absorption spectra.…
Exchange interaction in rare-earth-doped IV-VI diluted magnetic semiconductors
The magnetization and magnetic susceptibility of Bridgman-grown ${\mathrm{Sn}}_{1\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Gd}}_{\mathit{x}}$Te samples with values of x up to 0.09 have been measured in fields up to 5.5 T over a temperature range from 2 to 300 K and in fields up to 23 T at 4.2 K. The low-field, high…
Molecular biology of the 2-haloacid halidohydrolase IVa from Pseudomonas cepacia MBA4
The structural gene (hdl IVa) for the Pseudomonas cepacia MBA4 2-haloacid halidohydrolase IVa (Hdl IVa) was isolated on a 1.6 kb fragment of Ps. cepacia MBA4 chromosomal DNA. The recombinant halidohydrolase was expressed in Escherichia coli and Pseudomonas putida and the structural gene was subcloned on to the tac exp…
Correlation of the electrical properties of metal contacts on diamond films with the chemical nature of the metal-diamond interface. I. Gold contacts: A non-carbide-forming metal
The gold--polycrystalline-diamond interface has been characterized by x-ray-photoelectron-spectroscopy (XPS), Auger-electron-spectroscopy (AES), and current-voltage (I-V) measurements. The I-V characteristics of gold contacts on polycrystalline diamond were correlated with interface observations by XPS and AES. Minima…