Materials Literature
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Aqueous solutions of methylcellulose (MC) were studied as a function of temperature. It is well known that semi-dilute MC solutions are forming a gel upon heating. The gelation phenomenon is time-dependent and reversible but with a hysteresis. Different cyclic thermal treatments were conducted characterizing the forma…
The effect of alkali metals, such as Na, added to silica-supported copper (Cu/SiO2) catalysts has been studied in the gas-phase catalytic oxidation of benzyl alcohol. The main products were benzaldehyde as a partial oxidation product and carbon dioxide as a complete oxidation product. The silica-supported copper catal…
A mechanism of transition metal silicide-catalysed hydrodehalogenation of silicon tetrachloride to trichlorosilane is proposed. The overall reaction includes electron transfer steps from the metal silicide catalyst to adsorbed silicon tetrachloride molecules. A silylene species (SiCl2), which is formed from SiCl4 and…
Abstract The irreversible adsorbates formed after exposure of platinum to an NO‐containing solution were studied with Differential Electrochemical Mass Spectrometry (DEMS), Fourier‐Transform Infrared Spectroscopy (FTIRS) and cyclic voltammetry. DEMS and FTIRS show that only a very small amount of N 2 O is formed in th…
The effect of reactive compatibilization on adhesion at the interface between the immiscible polymers polystyrene and poly(2-vinylpyridine) was investigated. Reactivity was incorporated into the system by lightly sulfonating the polystyrene component, providing acid functionality which is coreactive with the basic pyr…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTStepwise Synthesis of Substituted Dicyanotriazolehemiporphyrazines. A Regioselective Approach to Unsymmetrically Substituted Hemiporphyrazines†Gema de la Torre and Tomás TorresView Author Information Departamento de Química Orgánica (C-I), Universidad Autónoma de Madrid, E-2804…
A series of copper(bis-β-diketonate) complexes are reported which display columnar liquid-crystal phases with a hexagonal disordered structure ( D hd ). The complexes do not have the disc-shape characteristic of most D hd materials, but produce a disc shape by forming dimers with 90 o rotations between nearest neighbo…
The surface-enhanced Raman spectrum of pyromellitic dianhydride (PMDA) on Cu(100) is reported; it is different from that previously reported for the Cu(111) surface. The spectra are sensitive to the incident laser polarization on both surfaces but in different ways. These observations are shown to be inconsistent with…
Circularly polarized luminescence (CPL) and total luminescence of Tb(III) and Eu(III) as substitutional replacements for iron in a series of Fe binding transferrins are reported. The measurement of the total emission intensity is a direct measure of binding of the lanthanide ions and illustrates that approximately 2 e…
It is shown that in unfilled polyester, and that filled with Al/sub 2/O/sub 3/, the conductivity is Ohmic at low field strengths and space charge limited (SCL) at high fields. With ZnO, however, its non-linear, semi-conducting characteristic changes the conductivity of the filled polyester at sufficiently high concent…
Silicon nitride was formed by nitriding acid-leached and pyrolyzed rice husk in a nitrogen atmosphere. The nitridation kinetics of the pyrolyzed husk pellet over a temperature range of 1473−1723 K were studied by a thermal gravimetric analysis (TGA) technique. The effects of gas flow rate, pellet size, pellet-forming…
Cationic, phosphine-ligated Pt−Au cluster compounds, [Pt(AuPPh 3 ) 8 ](NO 3 ) 2 ( 1 ) and [(PPh 3 )Pt(AuPPh 3 ) 6 ](NO 3 ) 2 ( 2 ), have been immobilized on silica and alumina supports. Characterization of the supported clusters by 31 P MAS NMR, IR, and UV−visible spectroscopy and study by chemisorption and temperatur…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTA Facile Synthesis and the Polymerization of Macrocyclic 1,4-Phenylene Sulfide (PPS) OligomersYi-Feng Wang and Allan S. HayView Author Information Department of Chemistry, McGill University, Montreal, Quebec, Canada H3A 2K6 Cite thi…
Extended X-ray absorption fine structure (EXAFS) spectroscopy was used to investigate the effects of oxidation and reduction on supported noble metal clusters. After long-term exposure to laboratory air at room temperature, platinum clusters with an average diameter of approximately 7 Å inside the pores of BaKLTL zeol…
The compound (dabcoH(2))(2)Cl(3)[CuCl(3)(H(2)O)(2)].H(2)O, where dabco = 1,4-diazabicyclo[2.2.2]octane, has been synthesized, its structure has been determined by single-crystal structural analysis, and its properties have been investigated by powder and single-crystal EPR spectroscopy. The compound crystallizes in sp…
The oriented-gas approximation was examined at the molecular level by using an ab initio molecular orbital method in order to investigate its basic assumption: the additivity of hyperpolarizabilities between molecules. The additivity was examined in an interacting 2-methyl-4-nitroaniline (MNA) pair, the first-neighbor…
Polarized laser Raman and FTIR spectroscopies, as well as wide angle X-ray diffraction (WAXD), have been employed in order to investigate the distribution of molecular orientation in uniaxially drawn solution-cast films of well-characterized polyesters, bearing hexyl side chains, at different draw ratios. Both the sec…
The transport kinetics of methanol in PMMA have been studied over the temperature range 25−60 °C, using magnetic resonance imaging. It is shown that transport behavior changes from being relaxation controlled (Case II) at the lowest temperature to approaching Fickian behavior at the higher temperatures. It is also sho…
The C02-H20-MeC03 system C02-H20-MeC03 system equilibria kinetics of C02-H20-MeC03 system evolution precipitation treatments decarbonation iron and manganese removal neutralization conditioning using scale inhibitors studies of different scale inhibitors other scale prevention methods treatments involving complexants…
The preparation of the alpha-1 and alpha-2 isomers of the Wells-Dawson 17 tungsto derivatives by standard methods is accompanied by a significant proportion of the other isomer present as an impurity. In this study, the alpha-1 and alpha-2 isomers of [Zn(H(2)O)P(2)W(17)O(61)](8)(-) have been prepared in >98% purity by…