Materials Literature
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Amino-functionalized poly(arylene ether ketone)s have been synthesized by nucleophilic aromatic substitution from isomeric amino-functionalized monomers and Bisphenol A. The polymerizations have been found to proceed without any side reactions. The polymers were characterized by IR, 1 H NMR, and 13 C NMR spectroscopy…
Pure iridium oxide has been synthesized through a chimie douce process. This synthesis proceeds by a slow basic hydrolysis of hydrated iridium(III) chloride, at room temperature. A highly disordered oxihydroxide IrO 1.45 (OH) 1.10 ·1.5H 2 O is first obtained. It has been characterized by thermal analysis, particle-ind…
The formation of CdTe thin films by spray deposition using nanoparticle colloids has been investigated. Employing a metathesis approach, cadmium iodide is reacted with sodium telluride in methanol solvent, resulting in the formation of soluble NaI and insoluble CdTe nanoparticles. After appropriate chemical workup, me…
We consider phase separation in multicomponent systems in the limit as the free volume goes to zero. Excluded volume effects are taken into account via a pressure field which implicitly relates currents and forces. The pressure, obtainable from a divergence condition, may give rise to circulating currents. A simple de…
High molecular weight poly(phthalazinone)s with high glass transition temperatures were prepared by a novel N−C coupling reaction. New bis(phthalazinone) monomers ( 5a − f ), such as 7,7‘-oxobis[4-phenylphthalazin-1(2 H )-one] ( 5c ), were synthesized from the corresponding bis(phthalic anhydride)s ( 3a − f ) in two s…
This paper presents two approaches for calculating the iron-core and copper losses of a 25 kVA single-phase pole transformer subjected to low-frequency voltage harmonics: an approximate calculation and a finite-element computer model. These methods can be applied to any transformer of similar construction by simply ch…
A study to clarify the mechanism of the photochemical degradation of poly(3-alkylthiophene)s in the solid state was carried out. The isolation of two low molecular weight products allowed us to determine that the polymer, under irradiation of visible light, gives rise to singlet oxygen that will, in turn, cause oxidat…
Specific surface area and longitudinal wave ultrasonic velocity were measured in zinc oxide (ZnO) powder compacts partially sintered to different pore fractions ( P ). A linear correlation was observed between the reduction in surface area and the increase in ultrasonic velocity at all P up to the onset of pore closur…
Composite hydrogels of poly(acrylic acid) (PAA) and poly-(methyl metacrylate) (PMMA) reinforced with a bioceramic, TiO2, have been prepared by reactive moulding from a mixture of the bioceramic with PMMA beads and acrylic acid. Cylindrical specimens with various TiO2-polymer compositions, but a constant 3:1 PAA/PMMA r…
Various water-soluble polysulphonated and polycarboxylated porphyrins and some of their metallated derivatives have been prepared and their antiviral properties against human immunodeficiency virus (HIV-1, HIV-2), simian immunodeficiency virus and other viruses are reported. Besides these polyanionic compounds, two ne…
The activation of CH 4 over NiO/MgO was investigated via temperature-programmed reaction mass spectroscopy (TPR-MS). Over pure MgO, CH 4 is not activated, while over pure NiO, CH 4 is activated to CO 2 around 660 °C. There are two kinds of CH 4 activations over the NiO/MgO solid solution catalysts prepared by the impr…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTFractionation and Characterization of Microbial Polyesters Containing 3-Hydroxybutyrate and 4-Hydroxybutyrate Repeat UnitsFengying Shi, Richard D. Ashby, and Richard A. GrossView Author Information Department of Chemistry, Universit…
Abstract In this theoretical study, we investigate the molecular and electronic structures of symmetrical and unsymmetrical squaraine dyes. Such dyes can be represented by the formula D‐A‐D, where D is a donor group and A an acceptor moiety. We analyze the evolution in geometric structure that results from changing bo…
Composite hydrogels of poly(acrylic acid) (PAA) and poly-(methyl metacrylate) (PMMA) reinforced with a bioceramic, TiO2, have been prepared by reactive moulding from a mixture of the bioceramic with PMMA beads and acrylic acid. Cylindrical specimens with various TiO2-polymer compositions, but a constant 3:1 PAA/PMMA r…
A porous α-alumina tube of 2.4 mm o.d. with an average pore size of ca. 150 nm was coated with p-xylene solutions of polycarbosilane (PC) and polystyrene (PS). The weight fraction of PS to total solid mass (PC + PS) was varied as 0, 1, 3 and 5 wt% (denoted as PC-PSx for a solution of x wt%). Then the film was cured in…
Two mutant forms of fumarase C from E. coli have been made using PCR and recombinant DNA. The recombinant form of the protein included a histidine arm on the C-terminal facilitating purification. Based on earlier studies, two different carboxylic acid binding sites, labeled A- and B-, were observed in crystal structur…
The structures of magnesium chloride thin films grown on a Pd(111) surface have been studied using low-energy electron diffraction (LEED), temperature-programmed desorption, and Auger electron spectroscopy. At coverages slightly less than 1 monolayer a Pd(111)−(4×4)−MgCl 2 LEED pattern is observed by LEED that correla…
We provide a reciprocal relation linking the effective conductivity of a composite with highly conducting phase interfaces to that of a composite with the same phase geometry but with an electrical contactresistance at phase interfaces. A field relationship linking the electric field inside a composite with highly con…
Additions of urea were found to increase the yield of nickel sulfide formation from acidic solutions of thioacetamide. Two precipitation mechanisms were identified: hydrolysis and direct reaction between nickel and thioacetamide. Hydrolysis‐controlled precipitation is evident with low initial pH. The direct reaction i…
New possibilities for realization of narrow-band transmission filters are introduced. Guided-mode resonance effects in thin-film multilayer structures incorporating a grating layer are shown to yield high-efficiency bandpass transmission filters. Calculated transmission characteristics for such filters are presented a…