Materials Literature
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Spherical and cylindrical adaptive liquid-crystal lenses are proposed. The modal principle of control of the distribution of the refractive index over the aperture is used in these lenses. This control is achieved by introducing an additional high-resistance electrode and placing low-resistance contacts at the periphe…
The facile, high-yielding synthesis of a series of macrocycles 7a-k in 75-100% yield is reported. The transformation of these compounds to their carboxymethylated analogues 8a-k in 75-90% yield and subsequent gadolinium complexes 9a-k provides a series of homologous neutral paramagnetic contrast agents (PCAs) with tun…
Isothermal desorption kinetics at different temperatures of 1,2-dichloroethane (DCE) from syndiotactic polystyrene films have been studied by Fourier transform infrared spectroscopy. For β-form films, where DCE is present only into the amorphous phase, nearly equal populations of trans and gauche conformers, during th…
The synthesis, crystal structure, electronic and second-order nonlinear optical (NLO) properties of a new bis(salicylaldiminato)nickel(II) Schiff-base complex are reported. The compound crystallizes in the space group P 1̄. The NLO properties are investigated by electric field induced second harmonic (EFISH) and by IN…
We describe a simple and low-cost apparatus for in-vacuum helium diffusion measurements that reduces temperature gradients, set point overshoot, and ramping times compared with conventional resistance furnace techniques. The sample, suspended by a thin wire in a vacuum chamber, is heated by radiation from an Al-coated…
Cysteamine (2-aminoethanethiol) monolayers were spontaneously formed on silver surfaces by chemisorption from cysteamine and cystamine solutions. The present surface-enhanced Raman scattering investigation of such layers shows that the conformation of the adsorbed molecules clearly depends on the preparation procedure…
Scanning force microscopy on monodendron-jacketed linear polystyrenes demonstrated unusual conformations and ordering depending on the branching density and interplay between intramolecular and surface interactions of the dendritic coat. Single molecules were visualized as wormlike cylinders, which could be twisted to…
We report results on the linear viscoelasticity (oscillatory shear in the temperature range T g (glass-transition temperature) ≤ T ≤ T g + 90 K) of miscible blends of polystyrene (PS) and poly(vinyl methyl ether) (PVME) and segmental relaxations, measured by dielectric spectroscopy. The Flory−Huggins interaction param…
We solve a coarsening system with small but arbitrary anisotropic surface tension and interface mobility. The resulting size-dependent growth shapes are significantly different from equilibrium microcrystallites, and have a distribution of grain sizes different from isotropic theories. As an application of our results…
Carbon nanotube-containing poly(phenylacetylenes) (NT/PPAs) are prepared by in situ polymerizations of phenylacetylene catalyzed by WCl 6 −Ph 4 Sn and [Rh(nbd)Cl] 2 (nbd = 2,5-norbornadiene) in the presence of the nanotubes. The NT/PPAs are characterized by GPC, NMR, UV, FL, TGA, SEM, TEM, and XRD, and it is found tha…
Gas permeation experiments of O 2 and N 2 were performed with conducting polyaniline (PANi) composite membranes prepared by using a porous nylon membrane as a support. PANi composite membranes were easily obtained by a novel solvent welding process. Doping, dedoping, and redoping kinetics of PANi composite membranes w…
The first direct characterization of structures of bi-molecular chain assemblies in a self-consistent series of pillared, layered organic−inorganic long-chain silver ( n- alkane) thiolates, (AgS(CH 2 ) n CH 3; n = 5, 6, 9, 11, 15, and 17), is reported using the combined application of infrared transmission spectroscop…
Human p32 (also known as SF2-associated p32, p32/TAP, and gC1qR) is a conserved eukaryotic protein that localizes predominantly in the mitochondrial matrix. It is thought to be involved in mitochondrial oxidative phosphorylation and in nucleus-mitochondrion interactions. We report the crystal structure of p32 determin…
The dipole moment of any finite and neutral system, having a square-integrable wavefunction, is a well defined quantity. The same quantity is ill-defined for an extended system, whose wavefunction invariably obeys periodic (Born-von Karman) boundary conditions. Despite this fact, macroscopic polarization is a theoreti…
Thermodynamics of Crystals is a gold mine of a references bargain with more derivations of useful equations per dollar, or per page, than almost any other book I know. Useful to whom? To the solid state physicist, the solid state chemist working the geophysicist, the rock mechanic, the mineral physicist. Useful for wh…
The disposition of actinides, most recently 239Pu from dismantled nuclear weapons, requires effective containment of waste generated by the nuclear fuel cycle. Because actinides (e.g., 239Pu and 237Np) are long-lived, they have a major impact on risk assessments of geologic repositories. Thus, demonstrable, long-term…
Clay minerals are layer type aluminosilicates that figure in terrestrial biogeochemical cycles, in the buffering capacity of the oceans, and in the containment of toxic waste materials. They are also used as lubricants in petroleum extraction and as industrial catalysts for the synthesis of many organic compounds. The…
We use a generalized van der Waals molecular theory to study a model substrate-nematic interface in the regime of complete wetting and in a situation of competing interactions at the interface. The analysis shows that an anchoring transition between states with planar and homeotropic director configuration may play th…
The luminescence characteristics of a two-component electroluminescent (EL) phosphor, SrS:Cu,Ag, were investigated by optical spectroscopy. Motivated by the discovery of efficient EL from SrS:Cu, SrS:Ag was investigated but exhibited poor EL emission, even though it showed a superior blue color. Thus, SrS:Cu,Ag sample…
Anomalously high metal–insulator transition temperature Tp and ferromagnetic transition temperature Tc have been observed in thin films of La0.8Ca0.2MnO3. Ferromagnetic resonance signals from microwave studies are observed at room temperature (well above Tc) suggesting the presence of multiple magnetic spin systems. T…