Materials Literature
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Pseudomonas oleovorans was grown separately on 5-(4‘-tolyl)valeric acid, 5-(4‘-ethylphenyl)valeric acid, 5-(4‘-biphenyl)valeric acid, and 8-(4‘-tolyl)octanoic acid either as the sole carbon source or as a coefeed with either nonanoic acid or 5-phenylvaleric acid. For polymer production, 5-(4‘-tolyl)valeric acid was th…
The effects of various surfactants on the interfacial tension between supercritical CO 2 and 600 MW polyethylene glycol (PEG) are reported at 45 °C on the basis of measurements with a novel tandem variable-volume pendant drop tensiometer. The interfacial tension of the CO 2 −polyethylene glycol binary system decreases…
The electron-transfer reactivity of microperoxidase-8 (MP8), the heme octapeptide derived from enzymatic cleavage of cytochrome c, has been studied by nanosecond flash photolysis methods. Ferric MP8 is rapidly oxidized by photogenerated Ru(bpy) 3 3+ in acidic solutions to a ferric cation-radical porphyrin ( k ∼ 5.6 ×…
Biotechnologically produced poly[( R )-3-hydroxybutyrate] (PHB) was subjected to catalytic depolymerization in the melt and in solution. In the melt depolymerization yields crotonic acid beside linear oligomers according to an ester pyrolysis reaction independent of the catalyst used. In solution cyclic oligomers were…
A new crystalline polymorph of Bombyx mori silk, which forms specifically at the air−water interface, has been characterized. This new polymorph has a trigonal crystal structure and is distinctly different from the two previously observed silk crystal structures, silks I and II. Our identification of this new silk pol…
The formation of phase inversion membranes made by immersion precipitation from a ternary system consisting of an amorphous polymer, a solvent, and a nonsolvent has been rationalized by assuming a gelation process. The treatise is based on a hypothesis developed by Berghmans for a binary system consisting of a polymer…
Reaction of CuI or CuBr with some imino nitroxides in methanol gave the halogen bridged dinuclear Cu(I) complexes [Cu(&mgr;-I)(impy)](2) (1), [Cu(&mgr;-I)(immepy)](2) (2), [Cu(&mgr;-Br)(immepy)](2) (3), and [Cu(&mgr;-Br)(imph-NO(2))](2) (4), respectively (impy = 2-(2'-pyridyl)-4,4,5,5-tetramethyl-4,5-dihydro-1H-imidaz…
The electrochemically induced substitution of thin films of polypyrrole, polythiophene, poly(3-methylthiophene), and poly(2,2‘-bithiophene) with the nucleophiles Cl -, Br -, methanol, and 3-bromopropanol has been investigated by cyclic voltammetry, electron microprobe analysis, IR spectroscopy, and NMR spectroscopy. T…
The purpose of this research was to create a truly practical but not nevertheless simplistic diatomic index capable of significantly improving the link between the index score and the overall water quality, insofar as the auto-ecology of the species permits. / L'objectif de cette recherche est de créer un indice diato…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTObservation of the Early Stages of Crystallization in Polyethylene by Time-Dependent SAXS: Transition from Individual Crystals to Stacks of LamellaeT. Albrecht and G. StroblView Author Information Fakultät für Physik Universität Freiburg, Hermann-Herder-Strasse 3, D-79104 Freib…
Three significant modifications to existing methods for the preparation of the important 5,10,15,20-tetrakisarylporphyrins have improved isolated yields, simplified work-up and made large-scale synthesis feasible.Two teuakisalkylporphyrins were also produced.A two-stage approach using hydrogen peroxide in acetic acid…
The heterometallic complex (NH(3))(2)YbFe(CO)(4) was prepared from the reduction of Fe(3)(CO)(12) by Yb in liquid ammonia. Ammonia was displaced from (NH(3))(2)YbFe(CO)(4) by acetonitrile in acetonitrile solution, and the crystalline compounds {[(CH(3)CN)(3)YbFe(CO)(4))](2).CH(3)CN}(infinity) and [(CH(3)CN)(3)YbFe(CO)…
Control over the shapes of biologically formed crystals is generally not well understood. We have studied the morphogenesis of the different-shaped calcareous sponge spicules using high-resolution synchrotron X-ray diffraction. We show that a remarkable correlation exists between the distribution of defects within spi…
Described here is a QSPR equation for calculating glass transition temperatures for acrylate and methacrylate polymers, especially those with bulky ester substituents. This approach is based on molecular mechanics calculations and exclusively involves a force field to describe a particular polymer system; i.e., no gro…
Conventional quenching methods were used to prepare (50-x/2)Na 2 O.xBi 2 O 3 . (50-x/2) P 2 O 5 system phosphate glasses for x≤16.0. The glass structure was then analysed with infrared and 31 P MAS NMR spectroscopy. The main phosphate species formed by the depolymerisation of the sodium metaphosphate chains by Bi 2 O…
We examine the surface segregation behavior of binary polymer blends with architecturally asymmetric components. Particular attention is given to molten blends containing linear and branched polymers composed of the same type of monomer. If the branches are sufficiently long and the branch points (joints) dilute, we a…
In an attempt to improve on the properties of PEDOT (poly(3,4-ethylenedioxythiophene)) as a stable, conducting, and transparent coating we synthesized four different alkoxy-substituted poly(thienylene−vinylene)s, 1 − 4, using the Stille coupling reaction. The oligomers and polymers obtained were characterized and thei…
An all-aromatic thermosetting copolyester has been prepared using hydroquinone, hydroxybenzoic acid, isophthalic acid, trimesic acid, and/or 1,3,5-triacetoxybenzene as key building blocks. The preparation and characterization of these materials are described. Cured resins based on these structures exhibit thermal stab…
In this paper, the authors deal with the effects of inverter characteristics on iron losses in induction motors fed by pulsewidth modulation (PWM) controlled power converters. Laboratory tests based on no-load input power measurements were carried out and in order to avoid the influence of mechanical losses and rotor…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTMolecular UmbrellasVaclav Janout, Marion Lanier, and Steven L. RegenView Author Information Department of Chemistry and Zettlemoyer Center for Surface Studies Lehigh University, Bethlehem, Pennsylvania 18015 Cite this: J. Am. Chem. Soc. 1996, 118, 6, 1573–1574Publicati…