Materials Literature
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Fullerenes have been converted to diamond crystals with the size of 0.1 mm at 5.0–5.5 GPa and 1400 °C, using NiMnCo catalyst. They are similar to graphite in the growing phenomena. They are transformed into diamond directly without being graphitized first.
We report high-resolution electron-energy-loss (HREEL) spectra at low energy (0--20 eV) on solid multilayer films of Ar. The present results are compared with optical data of similarly deposited films as well as with electron-energy-loss spectroscopy of Ar in the gas phase. Relatively wide and intense bands located at…
Calculations based on simple interaction potentials are performed to define the adsorption characteristics of molecules encapsulated in carbon nanotubules. The continuum approximation used to describe the cylindrical sheets is shown to work fairly well within a large range of tubule diameters. Criteria for molecule co…
X-ray-photoelectron spectroscopy (XPS) and optical measurements have been performed to investigate the structure of electronic states in yttrium-stabilized zirconia. From reflectivity observations, the spectral behavior of the dielectric function, of the energy loss, and of the effective electron number in the range 3…
Forces on the host-metal atoms surrounding a hydrogen atom at different interstitial positions in palladium and niobium are calculated from first principles in the local-density approximation with a mixed-basis pseudopotential supercell approach. For supercells ${\mathrm{Pd}}_{\mathit{n}}$H (n=1,4,8,16,32) previously…
Various NO-reduction reactions on Pt(100) exhibit similar dynamical behavior, presumably due to an empty site requirement for NO dissociation. This motivates analysis of a lattice-gas model which incorporates this feature, and which here is chosen to mimic the NO+CO reaction on Pt(100): both reactants adsorb at single…
Electrical transports of LaFe 1- x Ti x O 3 ( x ≤0.10) containing ligand holes (3 d 5 L ) were investigated by dielectric properties, ac and dc conductivities. A dielectric relaxation peak appeared with the activation energy which increased from 0.49 eV to 0.56 eV with increasing the amount of Ti ions. A thermal activ…
The dispersion of the nonlinear refractive index of direct-gap semiconductors, over the full sub-band-gap spectral region, is determined within the four-band Kane model. The divergences of individual terms in the nonlinear susceptibility, which have prevented previous full calculations, are avoided by selecting suitab…
We have studied the molecular orientational order and director kinetics of the nematic phase formed by dissolving poly-p-phenylene-terephthalamide (PPTA) in sulphuric acid using deuterium NMR spectroscopy. Measurements were made on standard polymer samples using deuterated sulphuric acid and with deuterated PPTA in no…
Waveguide losses in thin film polyimides using waveguide loss spectroscopy and photothermal deflection spectroscopy as a function of cure cycle and structure were studied. Fluorinated sidegroups on the polyimide backbone lead to decreases in birefringence and absorption. The primary waveguide loss mechanism is absorpt…
After coating with a smooth, nonreactive, sputtered gold layer, previously nonemitting chemical vapor deposited diamond films are observed to emit electrons in an applied field of 30–50 kV/cm in an electron emission microscope. The gold overlayer increases the effective field strength applied to the film. The conseque…
The elastic backscattering of medium-energy (200--2000 eV) electrons from noncrystalline materials has been investigated experimentally, theoretically, and with a Monte Carlo (MC) technique. A theory for elastic electron backscattering has been developed. In this theory, single scattering events are treated exactly wh…
Abstract The anionic polymerisation of ε‐caprolactam in a corotating, intermeshing twin‐screw extruder is discussed in terms of the materials formulation, extruder screw profile, and processing parameters such as temperature and screw speed. Using a variety of analytical characterization techniques, it is demonstrated…
Within the framework of the local-density approximation and the ab initio pseudopotential theory, it is shown that alloying of ${\mathrm{MgH}}_{2}$ with Li or Al may be described in terms of the rigid-band model. Metallization of insulating ${\mathrm{MgH}}_{2}$ upon doping with Li or Al should therefore be possible. D…
Anisotropic thermoelectric characteristics of a sintered Bi2Te3 system have been evaluated on the basis of the orientation distribution of crystallites. Uniaxially anisotropic resistivities, Hall coefficients, and thermal conductivities of sintered Bi2Te3 were expressed by linear combinations of those of single crysta…
Surface-induced ordering in block copolymer melts is studied numerically. For symmetric copolymers, the thickness of the surface-enrichment layer is found to scale as Req∼Nθ with θ≊0.6, suggesting the system is undergoing a surface-induced strong segregation. The density profile perpendicular to the interacting surfac…
Electronic states of graphite overlayers formed on the TaC(111) surface have been investigated with the use of scanning tunneling microscopy and photoelectron spectroscopy. The graphite film grows on the substrate layer by layer. The thickness of the overlayer has been adjusted precisely to be either one or two monola…
We report the results of structural, chemical, and extreme ultraviolet (EUV) characterization of Si/Mo multilayers grown by sputtering and by UHV evaporation. This study includes mirrors designed for normal incidence with peak reflectivities Rpeak between 22 and 24 nm, and 45° mirrors having Rpeak between 16 and 19 nm…
Porous silicon (PS) with its distribution of crystallite sizes is a highly disordered material. We present a theoretical formulation to explain the photoluminescence (PL) spectra of porous silicon. We base our formalism on the quantum confinement model using methods similar to those of Kane and Lifshitz. A minimal set…
By means of Monte Carlo simulations of a lattice model, microphase separation transition of symmetric diblock-copolymer melts confined in the thin-film geometry between parallel hard walls is studied. We impose a surface field which acts repulsively only on one of the two species, to stabilize lamellar order parallel…