Materials Literature
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A photo-alignment of nematic liquid crystals (NLC) on a photopolymer film of polyvinyl cinnamate (PVCi) has been achieved by using linearly-polarized UV light. The mechanism of the LC alignment is clarified and good unidirectional LC alignment with pretilt angle is obtained by appropriate combination of normal and obl…
Electron energy-loss spectroscopy measurements have been made on carbon and BN polymorphs, as well as on a number of borides, carbides and nitrides present in sintered cBN based compacts. The similarity in crystal symmetry between carbon and the isotructural BN system results in spectral similarities in both the low-l…
Sequential condensation of a variety of porphyrin-2,3-diones with 1,2,4,5-benzenetetramine and 1,10-phenanthroline-5,6-dione generate conjugated phenanthroline-appended porphyrin systems; this chemistry provides a means by which porphyrin π-systems can be connected to external redox centres.
Langevin-equation simulation is used to study the dynamics of a simple model of homopolymer collapse at infinite dilution for polymers of lengths N=100, 200, 300, 500, and 1024 units. Lennard-Jones potentials are chosen to represent the bead–bead interactions and a harmonic potential bonds nearest-neighbor beads. The…
Thermotropic Liquid Crystals Based on Amphiphilic Carbohydrates The paper gives an advanced report (related to the reviews of Jeffrey) on thermotropic mesogens based on carbohydrate amphiphiles. The different influences being responsible for the formation, stabilization, and for the type of the mesophases, such as the…
A thermally stable vanadium-containing mesoporous molecular sieve, V-HMS is synthesized at room temperature; V-HMS catalysts exhibit excellent catalytic activity in the oxidation of phenol and 2,6-di-tert-butylphenol using either hydrogen peroxide or tert-butyl hydroperoxide as the oxidant.
Backbone anisotropy and the structure of the mesophases of a series of side-chain liquid crystal polymers have been studied in the bulk by neutron scattering. The backbone conformation is obtained by small-angle neutron scattering on mixtures of hydrogenous polymers with deuteriated backbones. The components of the ra…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTMolecular Scaffolds. 2. Intramolecular Hydrogen Bonding in 1,2-Diaminoethane DiureasJames S. Nowick, Muna Abdi, Keith A. Bellamo, Jennifer A. Love, Eduardo J. Martinez, Glenn Noronha, Eric M. Smith, and Joseph W. ZillerCite this: J. Am. Chem. Soc. 1995, 117, 1, 89–99Publicat…
One of the critical steps in the production of microcellular polymers is the dissolution of gas into a polymer matrix. In this paper, the formation of a gas and semi-crystalline thermoplastic solution is studied in the presence of a crystallizing matrix with particular emphasis on the ultimate effects of crystallinity…
A complete set of sum rules is obtained for polarization-dependent x-ray-absorption fine structure and x-ray circular magnetic dichroism (CMD), analogous to those for CMD derived by Thole et al. These sum rules relate x-ray-absorption coefficients to the ground-state expectation values of various operators. Problems w…
ADVERTISEMENT RETURN TO ISSUEPREVArticle[(Co(H2O)4)2(H2W12O42)]n6n-: A Novel Chainlike Heteropolyanion Formed by Paradodecatungstate and Cobalt(II) IonsCarlos Gimenez-Saiz, Jose Ramon Galan-Mascaros, Smaiel Triki, Eugenio Coronado, and Lahcene OuahabCite this: Inorg. Chem. 1995, 34, 2, 524–526Publication Date (Print):…
A three-dimensional field solution is presented for radially polarized permanent-magnet cylinders. The derived field formulae are evaluated in terms of finite sums of elementary functions. They are readily programmed and ideal for performing rapid parametric studies of the field distribution outside of cylinders made…
The luminescence behaviour of two macrocyclic ligands incorporating naphthyl fluorophores has been studied in water and acetonitrile. The ligands 1,4,7-tris(methylcarbamoylmethyl)-10-(2-naphthylmethylcarbamoylmethyl)-1,4,7,10-tetraazacyclododecane, 1 and 1,4,7,10-tetrakis(2-naphthylmethylcarbamoylmethyl)-1,4,7,10-tetr…
ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTStirring Rate as a Critical Parameter in Chiral Symmetry Breaking CrystallizationDilip K. Kondepudi, Kim L. Bullock, Jennifer A. Digits, and Portia D. YarboroughCite this: J. Am. Chem. Soc. 1995, 117, 1, 401–404Publication Date (Print):January 1, 1995Publication History Publ…
Effects of the Ti buffer layer on crystallization processes of lead-zirconate-titanate (PZT) films by the sol-gel deposition technique were investigated. The Ti buffer layer was deposited on a Pt/TiN/SiO 2 /Si substrate by electron beam evaporation at the back-pressure of 1×10 -11 Torr. Homogeneous crystalline PZT fil…
Experimental methods and concepts in high-speed loading dynamic crack propagation rate-dependence and impact fracture toughness of plastics impact behaviour of composites - modelling, characterization and effect on properties.
The catalytic oxidation of tertiary amines to the corresponding N-oxides by [XO4{MO(O2)2}4]3–(X = P or As, M = Mo or W) and by [M2O3(O2)4]2– with H2O2 as co-oxidant has been studied. Epoxidation of alkenes and oxidation of alcohols by [M2O3(O2)4]2– with H2O2 as co-oxidant has also been examined and compared with that…
Coordination of zinc porphyrins by pyridine ligands is used to construct macrocyclic complexes: the self-assembly properties of the cyclic oligomers depends critically on the covalent structure of the monomer units which can be selected to give stable di-, tri- or tetra- meric assemblies.
CuI-exchanged ZSM-5 contacted with N2 at room temperature or at 77 K exhibits a narrow IR band at 2295 cm–1. On the basis of 14N2/14N2 and 14N2/14N15N/15N2 isotopic substitution experiments this peak is assigned to the N—N stretching vibration of CuI—N2 end-on dinitrogen complexes formed on isolated CuI sites inside t…
Abstract A review is presented of recent experimental results of low temperature studies of composition driven metal-insulator transition in perovskite oxides of the ABO3 class. The evolution of physical properties like conductivity, tunnelling, density of states and magnetoconductivity has been studied at low tempera…