Materials Literature
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The effect of quantum confinement in PbSe quantum wells and dots is studied using tight binding calculations. Compared to zinc-blende semiconductors, unusual physical properties are predicted for rock salt PbSe nanostructures. The energy gap increases as the inverse of the size both for wells and dots. For PbSe nanocr…
Copper wires were prepared in a silicon oxide matrix using the methods of semiconductor manufacturing and were electrically characterized. The width of the smallest structure was 40 nm and of the largest, 1000 nm; the heights were 50, 155, and 230 nm. Many samples of each size have been measured in order to perform a…
We study thermodynamic properties of the high-temperature modification of fullerites on the basis of the Girifalco intermolecular potential. In the present work, using the Lindemann's melting criterion we estimate a possible melting curve Tm(P) of C60 fullerite. To take into account the lattice anharmonicity that has…
Abstract The uniform tungsten oxide nanorods have been synthesized in large scale simply by heating a treated foil of tungsten. The diameter of the nanorods ranged from 100 to 300 nm and the length was up to 10 μm.
Abstract Hollow calcium carbonate particles were synthesized by a novel and facile approach which involves bubbling the CO2/N2 mixed gases into CaCl2 solution. The hollow particles were formed by the aggregation of nano-sized spherical particles on bubble surface. The formation mechanism was firstly proposed and the i…
From a quasi-racemic mixture of structurally related palladium complexes of opposite chirality, no quasi-racemic crystals were obtained. Rather, ligand exchange resulted in conventional racemic crystals. The crystal and molecular structures of the title complex, [Pd(C8H11N)(C5F6O2)], are reported.
Abstract A series of segmented polyurethane fluoroelastomers based on dimethylol‐terminated perfluoropolyethers (PFPEs), aliphatic diisocyanates and allyl functionality is presented. Depending on the type of diisocyanate monomer used, it was found that quite different prepolymer molecular weights were achieved. Therma…
We have used aqueous NaMnO4 solution as the deintercalation and oxidation agent to treat gamma-Na0.7CoO2 powders and to successfully obtain superconducting sodium cobalt oxyhydrates, Nax(H2O)yCoO2, with onset Tc approximately 4.6 K without using highly toxic Br2/CH3CN solution. Chemical analyses indicate that the sodi…
Abstract Conducting composites of polythiophene (PTP) and polyfuran (PF) with acetylene black (AB) were prepared via chemical oxidative polymerization of thiophene and furan in a suspension of AB in CHCl 3 at room temperature using anhydrous FeCl 3 as the oxidant. Formation of PTP and PF and their subsequent incorpora…
129Xe NMR spectra of xenon dissolved in acetonitrile confined into three mesoporous silica gels with nominal pore diameters of 40, 60, and 100 A have been measured over the temperature range 170-245 K. The spectra consist of a number of lines, which contain detailed information on the system. The most interesting resu…
A homologous series of novel λ-shaped mesogenic compounds in which three mesogenic groups are connected to 3, 4-dihydroxybenzoic acid has been prepared and their physical properties investigated by means of optical microscopy, differential scanning calorimetry and X-ray diffraction measurements. The λ-shaped compounds…
The electronic structure of inorganic solids such as Li(2)Ga and Li(9)Al(4) containing infinite zigzag homoatomic chains is discussed. It is shown that Li(2)Ga, a solid for which a Zintl-type electron-counting approach would suggest that a half-filled pi-type band occurs as in trans-polyacetylene, is really a three-di…
In the title compound, [(C4H9)4N][FeCl4], the central FeIII atom in the anion is tetrahedrally coordinated by four Cl atoms, while the cation exists as a central N atom bonded to four n-butyl groups, also in a tetrahedral arrangement. Both the cation and anion lie on crystallographic twofold axes.
Abstract A novel fluorine‐containing acrylic resin, 4‐trifluoromethylphenyl glycerol dimethacrylate (TPGD), was synthesized and the structure was characterized by FTIR, 13 C NMR, 1 H NMR, and 19 F NMR spectroscopy. The conversion of cure reaction, thermal stability, glass transition temperature ( T g ), and electrical…
Abstract A series of polyamides and poly(amide‐imide)s was prepared by direct polycondensation of ether and nitrile group containing aromatic diamines with aromatic dicarboxylic acids and bis(carboxyphthalimide)s respectively in N ‐methyl 2‐pyrrolidone (NMP) using triphenyl phosphite and pyridine as condensing agents.…
Abstract Complexation of chitosan in aqueous solutions by low molecular weight electrolytes is one of the simplest methods for the preparation of aqueous chitosan dispersions. In this work, the influence of storage time, sulfate concentration, method of preparation and surfactant content on some properties of the resu…
In this research, we fabricated thin films deposited on poly(ethylene terephthalate) (PET) films by a layer-by-layer self-assembly method using a roll-to-roll process and measured the morphology and transmittance of the thin films using atomic force microscopy (AFM) (nanoscope IIIa, Digital Instruments) and UV-vis spe…
A series of N-alkyl-N-methylpyrrolidinium bromide salts (C14, C16, or C18) have been explored as templates for the synthesis of ordered, mesoporous silica films; "soft" annealing based on deep-UV calcination is also reported.
Polymeric complexes based on diblock copolymers (polystyrene-block-4-vinylpyridine) hydrogen bonded with pentadecylphenol self-assemble under oscillatory shear flow into a highly ordered lamellar structure (Ikkala et al. Science 2002). Microtomed films of the lamellar structure form an array of "nanosheets"following i…
Abstract Blends of low‐density polyethylene (LDPE) and poly[ethylene‐ co ‐(vinyl acetate)] (PEVA), crosslinked by electron‐beam (EB) radiation, formed separate crystalline lattices with a homogeneous amorphous phase. The crystallinity of the EB‐exposed samples slightly decreased, as verified by a slight reduction in t…