Materials Literature
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ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTHydroxylation by cytochrome P-450 and metalloporphyrin models. Evidence for allylic rearrangementJohn T. Groves and Durga V. AdhyamCite this: J. Am. Chem. Soc. 1984, 106, 7, 2177–2181Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Publishe…
Among the various mesogenic polyaromatic cores, only benzene, triphenylene, truxene and anthraquinone hexasubstituted derivatives exhibit one or several D columnar phases and/or a ND lenticular nematic phase. A simple scheme of nomenclature is suggested for the six different types of columnar phase requiring only two…
Oxidative electrochemical polymerization of pyrrole has been shown to occur in the 1:1 mole ratio AlCl3:N-(l-butyl)pyridinium chloride((BuPyCl) molten salt at 40 C. Polypyrrole cannot be prepared in analogous 0.8:1 (basic) or 1.2:1 (acidic) mole ratio melts. The polypyrrole prepared in the molten salt is electrochemic…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTA new polymorph of chitosanKozo Ogawa, Shigehiro Hirano, Toshio Miyanishi, Toshifumi Yui, and Takehiko WatanabeCite this: Macromolecules 1984, 17, 4, 973–975Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Published inissue 1 April 1984http…
Donor additions to BaTiO 3 up to a few tenths atom percent are compensated by electrons and the resulting electrical conductivity is independent of temperature and P o 2 at 700° to 1000°C. The conductivities are impurity‐insensitive at very low Poz and high temperature where reduction is the major source of defects. V…
The Onsager theory for the isotropic–anisotropic phase separation in a solution of rodlike particles is extended to the case of mixtures of such particles with different lengths. The concentration, composition, order parameters, and orientation dependent thermodynamic quantities of the coexisting phases are calculated…
The x-ray diffraction patterns of liquid methanol and ethanol have been measured at 20 °C. The data are analyzed to yield the molecular structures, and the distinct structure functions Hd(k) are analyzed to obtain the hydrogen bonding in these alcohols. The data show clearly that hydrogen-bonded hydroxyl groups occur…
The dielectric properties and chemical homogeneity of BaTiO 3 ceramics sintered with additions of the pseudophase “CdBi 2 Nb 2 O 9 ” were investigated using SEM, TEM, STEM, and EDX. In materials showing the “X7R” dielectric temperature characteristic, the microstructure exhibits the grain core‐grain shell structure. T…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTViscoelastic properties of star-shaped polymersDale S. Pearson and Eugene HelfandCite this: Macromolecules 1984, 17, 4, 888–895Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Published inissue 1 April 1984https://doi.org/10.1021/ma00134a06…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTRegime III crystallization in polypropyleneElizabeth J. Clark and John D. HoffmanCite this: Macromolecules 1984, 17, 4, 878–885Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Published inissue 1 April 1984https://pubs.acs.org/doi/10.1021/m…
Abstract Olique-texture electron diffraction examination of K-saturated dioctahedral smectites after 70–100 wetting-drying cycles allows the determination of cation distribution between trans and cis octahedra of the 2:1 layers. Studies of smectites with different compositions has revealed a wide variety of occupancie…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTElectronic structure, magnetic properties, ESR, and optical spectra for 2-iron ferredoxin models by LCAO-X.alpha. valence bond theoryLouis Noodleman and Evert Jan BaerendsCite this: J. Am. Chem. Soc. 1984, 106, 8, 2316–2327Publication Date (Print):April 1, 1984Publication Hi…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTSolid-state high-resolution silicon-29 chemical shifts in silicatesM. Magi, E. Lippmaa, A. Samoson, G. Engelhardt, and A. R. GrimmerCite this: J. Phys. Chem. 1984, 88, 8, 1518–1522Publication Date (Print):April 1, 1984Publication History Published online1 May 2002Published i…
Determination of the crystal structure of ${\mathrm{Nd}}_{2}$${\mathrm{Fe}}_{14}$B, a new ternary phase, is reported. It has recently been demonstrated that permanent magnets having large coercivities and energy products can be formed from this phase, underscoring its potential technological importance. We relate the…
Data are presented on the EPR spectra of transition metal and Group IV metal complexes with o-semiquinone ligands. Analysis of the g-factors and the hyperfine coupling constants has been used to determine the structure of the complexes, the electronic configuration of the metal, and the ligand substitution processes.…
The use of dilute polymer solutions for molecular weight measurements requires the macromolecules to be in a true solution, i.e., dispersed on a molecular level. This state may not be realized in certain instances because stable, multimolecular aggregates may persist under the conditions of "solution" preparation. In…
In conventional x-ray diffraction experiments on single crystals, essentially monochromatic x-rays are used. If polychromatic x-rays derived from a synchrotron radiation spectrum are used, they generate a Laue diffraction pattern. Laue patterns from single crystals of macromolecules can be obtained in less-than 1 seco…
Phosphoprotein particles were isolated in their native state from the physiological fluid of the estuarine clam Rangia cuneata , and the characteristics of the mineral ion-protein complex which constitutes the native particle were investigated by using mineral ion binding and mineral ion exchange techniques. The parti…
Zero-field optically detected magnetic resonance (ZF-ODMR) is reported for the first time in semiconductors. The results of zero-field triplet magnetic resonances for the 1.91 eV emission in GaP:Cu are reported and compared with previous ODMR measurements. The potential of the technique for both crystalline and amorph…
The variation of birefringence in AlPO 4 is investigated between 300 and 90K. In the alpha phase it can be fitted very well with a classical law for first-order phase transitions. In qualitative agreement with previous c p measurements the possibility of intermediate states between the alpha and beta phases is derived…