Materials Literature
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A b initio calculations have been performed to study the structures and energies of intermediate-sized silicon clusters (Sin, n=7–10). All geometries have been optimized at the Hartree–Fock (HF) level of theory with the polarized 6-31G* basis set. The harmonic vibrational frequencies have been evaluated at the HF/6-31…
An investigation is made of the surface morphology and growth of polycrystalline diamond films deposited on Si substrates using the microwave plasma chemical-vapor-deposition (CVD) method. For the source gas, ${\mathrm{CH}}_{4}$ and ${\mathrm{H}}_{2}$ gases mixed in different concentrations are used. Scanning electron…
A novel x-ray diffraction technique, multiple-wavelength anomalous dispersion (MAD) phasing, has been applied to the de novo determination of an unknown protein structure, that of the "blue" copper protein isolated from cucumber seedlings. This method makes use of crystallographic phases determined from measurements m…
Anharmonicity in the lattice vibrations of oxygens in UO 2 has been examined by using EXAFS of the UL III absorption edge. Whilst the EXAFS-determined U-U distance of 3.89 AA closely matches the crystallographic separation, the U-O distance of 2.43 AA is 0.06 AA longer. This shift is interpreted on the basis of an anh…
Self-consistent spin-polarised electronic band structure calculations have been performed for La 2 NiO 4 in its nonmagnetic, ferromagnetic and antiferromagnetic states. The principal results are: the band structure of nonmagnetic tetragonal La 2 NiO 4 is similar to the isostructural La 2 CuO 4 , but with two Ni-O (3d(…
In an investigation of self-diffusion in bcc $\ensuremath{\beta}$-Ti single crystals by means of both quasielastic and inelastic neutron scattering, the elementary diffusion jump has been determined directly, and the lattice vibrations which trigger the jump have been elucidated. The elementary jump for self-diffusion…
We report preliminary dynamical structure-factor $G(q,t)$ measurements performed on polydisperse polymer cluster solutions at concentrations such that the largest clusters are partly penetrated by smaller clusters. Upon increase of the polymer concentration, the $G(q,t)$ profile goes from a stretched-exponential funct…
The authors introduce a new microscopic model for microemulsions. The model applies to continuum fluids as well as to lattice systems. In a mean-field treatment they show that, below a critical temperature, a microemulsion is formed. Different geometrical structures of the microemulsion (lamellar, tubular and cubical)…
Abstract A series of polyether block amide copolymers based on poly(tetramethylene oxide) of molecular weight 1000 or 2000 and polyamide 12 of molecular weight between 600 and 4000 with varying PE/PA weight ratio (from 80 to 20%) were studied by using dynamic mechanical spectroscopy and differential scanning calorimet…
Abstract A modified diffuse reflectance technique is used to characterize the surface hydrolysis of Kevlar‐49 fibers. Treatment with 10 wt% NaOH solution produces carboxylate groups on the surface which increase rapidly up to treatment times of about 20 min at room temperature or 50 min in boiling solution. After this…
Abstract The mechanism of action of aromatic sulfonates as flame retardant (FR) agents on poly(bisphenol‐A carbonate) (PC) has been investigated. These compounds are capable of inducing a self‐extinguence in PC even when present in very low amounts (0.2–1%). Thermogravimetric and flash pyrolysis–GC–MS data show the th…
Abstract The integral of loss modulus versus temperature plots in the vicinity of the glass transition temperature (loss area, LA) was characterized for various homopolymers, statistical copolymers, and interpenetrating polymer networks (IPNs), based on acrylics, vinyls, and styrenic mers. The quantity LA was found to…
Abstract Differential scanning calorimetry (DSC) and dynamic mechanical thermal analysis (DMTA) were used to characterize the morphology of solvent cast hydroxypropyl cellulose (HPC) films. DSC results were indicative of a semicrystalline material with a melt at 220°C and a glass transition at 19°C ( T 1 ), although a…
Abstract Macromolecules at the surface of a polymeric solid have considerable mobility, and the specific arrangement of functional groups of macromolecules at the surface is dictated by the environmental conditions in which the surface is placed. Consequently, the change of environmental conditions, such as immersion…
Abstract Surfaces of low density polyethylene, high density polyethylene, and polystyrene have been modified by grafting with acrylic acid. Benzophenone and acrylic acid in the vapor phase were UV‐irradiated in the presence of a polymer substrate. Grafting with acrylic acid took place in a thin layer on the surface, t…
This document consists of two sections. The first section presents the general theory of anisotropic shells. Initial equations are formulated for both thin shells and shells of average thickness. The nonlinear theory of thin shells in problems of stability is examined. Particular attention is given to axisymmetric str…
A modified bilayer resist scheme was studied that used poly(methyl methacrylate) (PMMA) as the bottom, deep ultraviolet (DUV) resist, a novolac‐based system as the top near ultraviolet (NUV) resist, and an intervening antireflective coating (ARC). The ARC consisted of a polyimide film formed by the thermal curing of a…
Article Thermodynamic Properties of the Fe-Co-Ni-C System / Thermodynamische Eigenschaften des Systems Fe-Co-Ni-C was published on August 1, 1988 in the journal International Journal of Materials Research (volume 79, issue 8).
Nur induktiv stabilisiert ist das Pentalenderivat 2, das aus dem Dihydroderivat 1 mit Nickelperoxid erhalten wurde. Aus einem Vergleich der spektroskopischen Daten mit den Ergebnissen von MNDO-Rechnungen läßt sich eine Dominanz der gezeichneten Kekulé-Struktur, d. h. eine Bindungsfixierung, ableiten.
(CH3)3 NHNO3 belongs to the monoclinic system with space group P21/c (C52h ) with four molecules per unit cell. Raman and infrared spectra (10–5000 cm−1) of single crystals and polycrystalline samples of (CH3)3 NHNO3 and of its N-deuterated derivative were investigated in the temperature range 90–415 K. Assignments of…