Materials Literature
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Abstract Conductive polymer composites were prepared by sintering a mixture of ultrahigh molecular weight polyethylene (UHMWPE) powder and carbon black. Two processing parameters—time and temperature—were shown to have a notable effect on the resistivity of the composites. The relationships between the processing para…
The reaction of the iron(II) picket fence porphyrin derivative [Fe(TpivPP)(NO 2 )] - (Nasri et al. J. Am. Chem. Soc. 1991, 113, 717) with NO has been examined. The result is a new hexacoordinated iron(II) porphyrin complex, [Fe(TpivPP)(NO 2 )(NO)] - . This compound has been characterized by UV−vis, IR, EPR, and Mössba…
The oxidation of 2,2‘-bipyrrole, 5-methyl-2,2‘-bipyrrole, and 5,5‘-dimethyl-2,2‘-bipyrrole has been investigated by means of electrochemistry, flash photolysis, and pulse radiolysis. The bipyrrole cation radical was found to give polypyrrole or oligopyrrole under electrochemical and chemical oxidation and also under U…
The phase behavior of a low molecular weight ( M W = 4000) diblock copolymer of polystyrene and poly(ethylene oxide), PS−PEO, in the bulk as well in aqueous, D 2 O, solutions has been studied using small-angle neutron-scattering, dynamic and static light-scattering, and rheological methods. At low temperature the pure…
The morphology of a miscible blend of two crystalline polymers (PVF 2 /PBA) has been investigated by synchrotron small-angle X-ray scattering. Measurements have been made as a function of blend composition and of temperature, probing the morphologies at both the spherulitic and the lamellar levels in both the semicrys…
A series of dendritic bis(oxazoline) ligands 1 − 4 were synthesized to evaluate the effects of the degree of branching of a dendritic sector on both the reactivity and selectivity of their corresponding copper(II) complex-catalyzed Diels−Alder reaction between cyclopentadiene and a crotonyl imide. Kinetic studies unve…
Two new compounds in the series of general formula [Mn(L)(2)(N(3))(2)](n)() in which L = 4-cyanopyridine (1) or 3-acetylpyridine (2) have been obtained and structurally and magnetically characterized. Both compounds crystallize in the monoclinic system, space group P2(1)/a, formula [C(12)H(8)MnN(10)] with a = 13.286(4…
Ordered nonlamellar mesoporous aluminophosphates and galloaluminophosphates have been synthesized by introducing phosphate linking groups to cluster/surfactants salts of prearranged AlO 4 Al 12 (OH) 24 (H 2 O) 12 7+ (Al 13 ) and GaO 4 Al 12 (OH) 24 (H 2 O) 12 7+ (GaAl 12 ) tridecamers. The Al 13 and GaAl 12 polyoxocat…
The spin, charge, and orbital ordering in ${R}_{0.5}{A}_{0.5}$MnO${}_{3}$ and ${R}_{0.5}{A}_{1.5}$MnO${}_{4}$ $(R$=rare earth, $A$=Sr, Ca) has been studied by means of unrestricted Hartree-Fock calculations on the multiband $p\ensuremath{-}d$ model. Since the superexchange interaction between the Mn${}^{3+}$ and Mn${}…
We study the effects of the degeneracy of the ${e}_{g}$ orbitals in perovskite transition-metal oxides in the limit of strong repulsive electron-electron interaction. The isospin field is introduced to describe the orbital degrees of freedom and is represented by the boson with a constraint. The dispersion of this bos…
Quantum chemical calculations by means of the semiempirical modified neglect of diatomic overlap and Austin model 1 (AM1) methods are presented for hexakis $(n$-alkoxy) triphenylene with $n=1$ and 4. The predicted molecular structures by the self-consistent electronic field are presented and discussed. The optimized g…
Abstract Organo‐soluble cellulose‐ p ‐toluenesulfonates (tosylates) with an insignificant incorporation of chlorodeoxy functions were prepared by reacting cellulose dissolved in N,N ‐dimethyl acetamide/LiCl and used as intermediates in the design of cellulosics with new, unusual molecular structures. Thus, the remaini…
Abstract Advanced evaluation techniques as Rietveld refinement applied to series of temperature resolved X‐ray diffraction measurements, provide an improved insight into the lattice dynamics. The transition paths of ammonium nitrate are clearly defined and coexisting phases are quantitatively determined. The curves fo…
Summary: Alcaligenes eutrophus was grown in continuous culture (34 °C, pH 6.8) under various conditions with respect to dilution rate, nutrient limitation and carbon substrate. Poly-3-hydroxybutyrate (PHB) content, the rate of PHB production ( q PHB ) and the rate of carbon substrate utilization ( q s ) during growth…
The winding process tends to promote yarn hairiness, a detrimental effect that can be significantly reduced by adding a properly arranged air-jet nozzle. This paper examines the mechanisms of hairiness reduction with an air jet during winding. The results indicate that the direction of the majority of protruding fiber…
Zinc hydroxystannate (ZHS), at levels of 2-5 phr, and the hydrated fillers, magnesium hydroxide (MH) and alumina trihydrate (ATH), at levels of 20–50 phr, are effective flame retardants and smoke suppressants for flexible PVC. Novel ZHS-coated hydrated fillers are found to exhibit markedly improved fire-retardant prop…
In order to determine the mechanisms of twin growth, a high-resolution electron microscopy study of the tip morphology in (1012) twin in zinc has been carried out. In a new model presented here, the twin tip is described as a series of (1012)//(1012) step faces, containing one or more interfacial dislocations. They ar…
Thin films of ClAlPc of 100 - 300 nm thickness were sublimed onto glass substrates in high vacuum. Studies of the molecular structure of ClAlPc have been made using films deposited at various temperatures and films annealed after deposition at room temperature. The optical properties in both monoclinic and triclinic f…
Examining the effect of nonhydrostaticity on the shape of x-ray powder diffraction lines shows that a uniaxial stress field, as is generated in opposed-anvil type high-pressure apparatuses, can result in lines being split or having an asymmetric shape. The distribution of local stresses, generated by mismatches in sha…
1,4,7,10-Tetrathia (12-crown-4)-bridged new polymeric phthalocyanines 9 and 10 have been synthesized by the reaction of tetracyanodibenzo[1,4,7,10-tetrathia (12-crown-4)] in the presence of a strong organic base or Zn ( OAc ) 2 respectively. Furthermore, 1,4,7,10-tetrathia (12-crown-4)-linked peripherally octa-substit…