Materials Literature
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We have studied transport properties (resistivity, Hall effect, thermopower, and thermal conductivity) of Bi 2 S 3 and two new ternary bismuth sulfides, KBi 6.33 S 10 and K 2 Bi 8 S 13, to explore their potential for thermoelectric applications. While both Bi 2 S 3 and K 2 Bi 8 S 13 display an essentially metallic con…
Abstract In this research, the effects of the materials and the processing conditions on the cell morphology of foamed PVC/wood‐fiber composites were studied with a view to establishing their process‐structure relationships. Each step of microcellular PVC/wood‐fiber composites processing is addressed, including the su…
A new formulation of the coupled-wave method for two-dimensional gratings is proposed. It is based on mathematical and physical results recently obtained for one-dimensional gratings. Numerical evidence obtained for many different diffraction problems, including dielectric, metallic, volume, and surface-relief grating…
Ferrous dodecyl sulfate, Fe(DS) 2, micellar solution was used to make nanosized magnetic particles whose size is controlled by the surfactant concentration and by temperature. The average particle size varies from 3.7 to 11.6 nm, with a standard deviation ranging from 0.22 to 0.34. In contrast to what is obtained in h…
The magnetic properties of oxo-bridged oxo-(carboxylato)-bridged and oxo-bis(carboxylato)-bridged iron(III) dimers are found to depend on the iron−(μ-O) distance as well as on the iron−(μ-O)−iron angle. With an angular and radial overlap model we account for both these dependencies. The use of an angular overlap model…
The specialized‐performance polymers poly(arylene‐1,3‐oxadiazole)s —see Figure for an example—have high‐value end uses based on their electronic, optical, and thermal properties. The syntheses, solid‐state structure, properties, and applications of poly(arylene‐1,3,4‐oxadiazole)s are reviewed. magnified image
Polymer-protected Pd−Pt bimetallic colloids in the size range 1.5−5.5 nm with controllable core/shell structures have been successfully prepared by a so-called hydrogen-sacrificial protective strategy. The obtained bimetallic colloids were characterized by transmission electron microscopy and infrared carbon monoxide…
New semiconductors and host materials are expected to be found among newly synthesized boron/carbon/nitrogen (B/C/N) materials based on the graphite network. The synthesis, structure, and properties of such materials, including solid solutions, more‐ordered B/C/N hybrids, and compounds (e.g., BC 3 , C 5 N, BC 2 N, BC…
Starting from a single precursor, bis(3-methoxysalicylaldehydato)copper (II), which contains an O(4)Cu chromophore, three routes to discrete dinuclear Cu(II)/Ln(III) complexes (Ln = Pr, Eu, Gd, Yb) are described. The pairs of chromophores occurring in the resulting complexes are either O(4)Cu/O(4)Ln or O(2)N(2)Cu/O(4)…
New reflection and transmission optical filters based on guided-mode resonances in multilayer waveguide gratings are characterized and compared with homogeneous thin-film filters. These guided-mode resonance filters are implemented by integration of diffraction gratings into classical thin-film multilayers to produce…
The crystal structure of the emptied clathrate form (δ e form) of syndiotactic polystyrene, obtained by removing the guest molecules from different clathrate δ forms, is presented. Chains in s(2/1)2 helical conformation are packed in the monoclinic unit cell with axes a = 17.4 Å, b = 11.85 Å, c = 7.70 Å, and γ = 117°…
Abstract Donor–acceptor polyenes of various lengths, and that combine aromatic electron‐donating moieties with powerful heterocyclic electron‐withdrawing terminal groups, have been synthesized and characterized as efficient nonlinear optical (NLO) chromophores. Their linear and nonlinear optical properties have been i…
The linear and nonlinear optical properties of donor−acceptor π-electron chromophores having conjugated bridges varying in aromaticity and electron excessivity are investigated using the INDO/1 semiempirical Hamiltonian. NLO response properties of such chromophores are more sensitive to the electron excessivity of the…
The first detection and characterization of oxomanganese(V) porphyrin complexes under ambient catalytic conditions is described. The reaction of (tetra-( N -methylpyridyl)porphyrinato)manganese(III) [Mn(III)TMPyP] with a variety of oxidants such as m -chloroperoxybenzoic acid ( m -CPBA), HSO 5 -, and ClO - has been sh…
ADVERTISEMENT RETURN TO ISSUEPREVCommunicationNEXTHighly Efficient Epoxidation of Olefins Using Aqueous H2O2 and Catalytic Methyltrioxorhenium/Pyridine: Pyridine-Mediated Ligand AccelerationJoachim Rudolph, K. Laxma Reddy, Jay P. Chiang, and K. Barry SharplessView Author Information Department of Chemistry, The Scripp…
wARP is a procedure that substantially improves crystallographic phases (and subsequently electron-density maps) as an additional step after density-modification methods such as solvent flattening and averaging. The initial phase set is used to create a number of dummy atom models which are subjected to least-squares…
UNLABELLED: An ideal hypoxia imaging agent should have high membrane permeability for easy access to intracellular mitochondria and low redox potential to confer stability in normal tissue, but it should be able to be reduced by mitochondria with abnormally high electron concentrations in hypoxic cells. In this contex…
The potentiostatic electrochemical template synthesis of nanowires (Ni, Co, Cu, Au, and polyporrole) in polycarbonate track-etched membranes with nominal pore diameters d N between 10 and 200 nm is studied. Along the wire the cross section is found to vary: the wire diameter, which is argued to directly reflect the po…
The electronic structure of spherical PbS and PbSe quantum dots is calculated with a four-band envelope-function formalism. This calculation accounts for both exciton energies and wave functions with the correct symmetry of the materials. The selection rules and the strength of the dipole transitions of lead-salt quan…
Cell adhesion and spreading of chick embryo vascular and corneal explants grown on rough and smooth poly (methyl methacrylate) (PMMA) were analyzed to test the cell response specificity to substratum surface properties. Different degrees of roughness were obtained by sand-blasting PMMA with alumina grains. Hydrophilic…