Materials Literature
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Abstract The results of ab initio and MNDO calculations of the Cl 2 C = CHOCH 3 , XCOCl (X = CH 3 , OCH 3 and COCl), 4-ClC 6 H 4 CH 2 Cl, (CNCl) 3 and PCl 5 with total optimization of their geometry are presented. The ab initio calculations were executed using Hartree-Fock theory and the split valence basis set 6-31G*…
Anodic oxides of thickness 1–10 nm have been grown on Si(100) using anodic oxidation at room temperature. The electrolyte was 0.1 M HCl. The effects of the anodic potential, growth time, external visible illumination intensity, substrate doping type, and density on the oxide thickness were determined. Coulometric and…
Electrical transport and the nature of carriers in the homovalent substitution LLaFe x Ni1–x O3 were investigated as a function of component, in the temperature range 10K–300K, by dielectric properties, dc and ac conductivities and thermopowers. At x > 0·6, the positive thermopowers indicate the major carriers of hole…
Mechanochemistry of hydrothermally prepared Al‐free and Al‐substituted 1.1 nm tobermorite was studied using 29 Si NMR, XRD, and TGA‐DTA. Tobermorite has a double‐chain structure and Al/Si substitution occurs preferentially at bridging tetrahedra. By using the vibration mill, both tobermorites were observed to decompos…
Summary Laboratory experiments were carried out to evaluate the effect of pH, ionic strength and electrolyte composition on zinc sorption–desorption by two Andepts from the Canary Islands (Spain). At the natural soil pH, the soils exhibited little net negative surface charge and small Zn sorption capacities. More than…
The dynamical properties of binary liquid mixtures are investigated within a viscoelastic model using the memory function approach. Extending the viscoelastic model to the binary case we find that the dynamical properties of the liquid mixture are characterized by four propagating and two diffusive modes. We show that…
Abstract Hydrogen- (δD = −106 to −97‰) and oxygen-(δ 18 O = +14.0 to +16.6‰) isotope compositions of kaolinite from late Cretaceous and Oligocene deposits at Iwaizumi, northeastern Japan, indicate that these clays formed by weathering of volcanic parent rocks, rather than during hydrothermal (>100 °C) alteration. T…
The strain energy per unit area for a deformed sheet of elastic material is estimated by representing the deformation as a power series in the thickness variable. The <italic>membrane</italic> energy is the lowest-order approximation obtained in this way. Strain-gradient and bending energies appear in the next order o…
Transparent mullite fibers have been prepared using aluminum carboxylates (ACs) and tetraethyl orthosilicate (TEOS) as starting materials. The ACs are derived from the catalyzed dissolution of elemental aluminum in a mixture of formic acid and acetic acid. The solubility of aluminum in the acids is influenced by the c…
Abstract Thin melt crystallized spherulitic films of isotactic polypropylene have been deformed in uniaxial tension at different temperatures and examined by transmission electron microscopy. As the temperature was increased above approximately −80°C, a transition from high aspect ratio craze‐like features to highly v…
Thermal and mechanical behavior of high power ZnO surge arresters under current pulses of various magnitude and duration is simulated. By solving heat transfer equations for a varistor disk with nonuniform electrical properties, we compute the time dependence of the temperature profile and the distribution of thermal…
Abstract An A–B–A triblock copoly(ester-ether) comprising poly(l-lactide) (A) and poly(oxyethylene-co-oxypropylene) (B) was prepared by copolymerization of l-lactide and a commercially available telechelic copolyether, Pluronic® (PN), with different molecular weights by the catalysis of tin(II) octanoate. The low mole…
Scanning tunneling microscopy (STM) was used to investigate the reaction of carbon monoxide with atomic oxygen on Cu(110) in the steady state at 150 K. Oxygen dosed at 150 K reacts with copper atoms on the terraces to form CuO pseudomolecules 2–7 units long, in contrast to oxygen dosed at 300 K which forms long Cu…
Human type II procollagen was prepared in a recombinant system and cleaved to pC-collagen II by procollagen N-proteinase. The pC-collagen II was then used as a substrate to generate collagen II fibrils by cleavage with procollagen C-proteinase at 37 degrees C. Electron microscopy of the fibrils demonstrated that, at t…
From thermal desorption spectroscopy we find that ferrocene, Fe(C5H5)2, adsorbs and desorbs associatively on Ag(100). Photoemission results indicate that the initially adsorbed surface species closely resembles that of molecular ferrocene. The shift in photoemission binding energies relative to the gas phase is largel…
A new model for the evaluation of the electric field in a cable termination realized through a nonlinear stress control tube (SCT), is presented in this paper. It is based on the electro-quasistatic approximation of the Maxwell equations: the Laplace equation describes the field in the nonconducting regions whereas a…
Crosslinking of 2,7-bis(4-maleimidophenoxy)naphthalene (BMPN) and 4,4-bismaleimi-dophenylmethane (BMPM) was investigated in the presence of 4,4-diaminodiphenylmethane (DDM) at the 2/1 molar ratio of bismaleimide/DDM. Their curing behaviors were characterized by infrared spectroscopy and differential scanning calorimet…
Contact angles of various liquids on wool fibers are measured using the liquid droplet method. A computational technique greatly simplifies contact angle calculations. Sur face energy components of differently treated wool fibers are determined from the contact angle data using current theories of surface energy. Valu…
The trans cis photoisomerization and angular reorientation of an azobenzene derivative (DR1) in dye-doped polymer matrices [poly(methyl methacrylate)], induced by linearly polarized visible illumination (λ0=496.5 nm), were investigated by dichroism measurements in the visible region and by polarized resonance Raman ex…
Water absorption characteristics, and developments of transverse tensile modulus and strength, and mode II fracture toughness with water absorption of a unidirectional glass/polypropylene (PP) composite have been examined. Immersion times up to 5 months at 50°C were employed. Overall, very small amounts of water were…