Materials Literature
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The resonance stabilized dithiazolo-dithiazolyl radical 1b adopts a slipped π-stack structure exhibiting weak 1-D ferromagnetic coupling; variable temperature conductivity measurements indicate σRT = 2 × 10−6 S cm−1.
MCM-41 was found to be an active heterogeneous catalyst for the synthesis of nopol by the Prins condensation of beta-pinene and paraformaldehyde, but Sn-MCM-41 in which Sn has been grafted on MCM-41 by chemical vapor deposition is far more active and combines high efficiency and recyclability.
The metal-insulator (M-I) transition in conducting polymers is particularly interesting; critical behavior has been observed over a relatively wide temperature range in a number of systems, including polyacetylene, polypyrrole, poly (phenylene vinylene) and polyaniline. In each case, metallic, critical and insulating…
The degradation of novel biodegradable segmented polyurethanes was investigated with a view to determining the cleavage points within the polymer backbones targeted by the enzyme chymotrypsin. While the materials were developed with specific enzyme cleavage sites designed into the polymer chains, the nature of their d…
The interaction between low dielectric constant (low- k ) hybrid organic siloxane polymer (HOSP) and O 2 plasma ashing has been investigated. O 2 plasma ashing is commonly performed to remove the photoresist (PR) during integrated circuit fabrication. However, dielectric loss usually occurs in the HOSP films during th…
Passivation on polycrystalline Zr (hcp) and Ta (bcc) depends on the crystallographic orientation of the individual grains, determined by electron back scattering diffraction (EBSD). Microelectrochemical experiments yield characteristic data, such as oxide formation potentials, formation factors, capacities, and thickn…
The purpose of this research was to evaluate the performance of a modified rolled homogeneous armor (MRHA) steel during ballistic impact tests. AerMet 100, AISI 1045 and 4130 steels were also tested for comparison with the MRHA results. The “white"‐etched portion of adiabatic shear bands was found on the front surface…
Tryptophan 128 of hydroxynitrile lyase of Manihot esculenta (MeHNL) covers a significant part of a hydrophobic channel that gives access to the active site of the enzyme. This residue was therefore substituted in the mutant MeHNL-W128A by alanine to study its importance for the substrate specificity of the enzyme. Wil…
Si 3 N 4 materials with distinct microstructures were prepared by hot‐pressing, varying the holding time at the maximum temperature, and using different types and amounts of sintering additives. Materials with thermal conductivities of 15–82 W·(m·K) −1 were obtained by changing the processing variables. The highest co…
The extensive information available in the literature for liquid film thickness measurement in multiphase systems has been critically reviewed. The review is structured by classification of the identified measurement techniques into groups of comparable measurement resolution. Each technique is reviewed in terms of de…
Java Island in Indonesia is dominated by volcanic ash soils. A study was conducted to characterize the soil’s physico-chemical properties in order to assess the influence of change of parent material on differing soil characteristics along an E-W sequence. All of the soils are Andisols of varying chemical composition.…
Diels-Alder reactions of nickel(II) N-confused tetraarylporphyrins as dienophiles with o-benzoquinodimethane yield nickel(II) N-confused isoquinoporphyrins.
This paper presents experimental results for the processing and mechanical properties of carbon fiber reinforced composites of a newly developed amorphous, asymmetric, and addition type polyimide (Triple-A PI). The imide oligomers were synthesized from the reaction of 2,3,3′,4′-biphenyltetracarboxylic dianhydride (a-B…
Directionally solidified B4C–SiC composites were prepared by a Floating Zone method. The lamellar texture was observed at 53 mol%SiC . The c-axis of B4C phase was tilted 20° to the growth direction. The (102) plane and [\\bar1\\bar21] direction of the B4C phase were parallel to the (311) plane and [12\\bar1] direction…
Research Article| January 01, 2002 Beryllium in Metamorphic Environments (emphasis on aluminous compositions) Edward S. Grew Edward S. Grew Department of Geological Sciences, University of Maine, 5790 Bryand Center, Orono, Maine 04469, esgrew@maine.edu Search for other works by this author on: GSW Google Scholar Revie…
Abstract The deformation mechanisms in polypropylene as a function of strain rate have been studied by scanning electron microscopy. Injection molded, dogbone specimens were tested in tension at a temperature of 50°C and strain rates from 10 −4 to 90 s −1 . With increasing strain rate a gradual transition from cold dr…
Highly dispersed uranium oxide nanocrystals supported on ordered mesoporous silica matrixes with large surface areas and porosities have been synthesized via a co-assembly methodology; the preliminary catalysis tests showed that these materials have a high catalytic activity for the thermal oxidation of volatile organ…
Supported lanthanum oxide catalysts were prepared by the impregnation method, using an aqueous solution of lanthanum nitrate hexahydrate (La(NO3)3·6H2O), then calcined at 920 K for 2 h. Characterization of the samples was carried out by X-ray diffraction, N2-adsorption at −196 °C and IR spectroscopy of the calcination…
The optical erasing of holographic gratings inscribed on azobenzene homopolymer thin films of p(DR1M) is analyzed for various polarizations of the erasing single beam. Gratings of different diffraction efficiencies are first inscribed using different states of the incident interfering beams, either linearly polarized…
Voltage shift phenomena of the hysteresis loop were characterized for a c-axis oriented heteroepitaxial BaTiO3 film by means of switching current measurements using various types of pulse sequences. During application of voltage, the hysteresis loop gradually shifted along the voltage axis according to the polarity of…