Materials Literature
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A sol-hydrothermal method has been proposed to prepare uniform and unaggregated nanocrystals of pure anatase and rutile from various acidic mediums. The phase formation, particle sizes, and morphologies varying with different acids and their concentrations at different reaction temperatures and times have been investi…
Conjugated polymers and indium arsenide-based nanocrystals were used to create near-infrared plastic light-emitting diodes. Emission was tunable from 1 to 1.3 micrometers--a range that effectively covers the short-wavelength telecommunications band--by means of the quantum confinement effects in the nanocrystals. The…
The interpretation of macromolecular crystallographic electron-density maps is a difficult and traditionally a manual step in the determination of a protein structure. The visualization of information within an electron-density map can be extremely arduous owing to the amount and complexity of information present. The…
The optical spectra of vapor quenched metastable Ag−Cu thin films progressively iodized under ambient conditions have been measured. Delayed evolution and inhomogeneous broadening of the exciton absorption at 420 nm of the spatially confined γ-AgI nanoparticles were clearly seen by the development of Z 1,2 exciton pea…
The local environment of Er3+ ions in microporous titanosilicate ETS-10 and in synthetic narsarsukite and glassy materials obtained by calcination of ETS-10 has been investigated by EXAFS, Raman and photoluminescence spectroscopies. Er LIII-edge EXAFS studies of Er3+-doped ETS-10 support the view that the exchanged Er…
Abstract Blends of polycarbonate (PC) and poly(alkylene terephthalate) (PAT) such as poly(butylene terephthalate) (PBT) and poly(ethylene terephthalate) (PET) were investigated. It was learned that processes of phase separation in blends consisting of PC and PAT can cause variations in properties of both the amorphous…
Powder neutron diffraction data collected for AMo 2 S 4 (A = V, Cr, Fe, Co) reveal that the materials crystallize in the space group Cc ( a ≈ 11.8 Å, b ≈ 6.5 Å, c ≈ 13 Å, β ≈ 114°). The structure consists of dichalcogenide (MS 2 ) layers of edge-sharing octahedra, separated by a layer in which 50% of cation sites are…
The nanoscale investigation of mixed arrays of Keggin-type (H 3 PW 12 O 40 ) and Wells−Dawson-type (H 6 P 2 W 18 O 62 ) heteropolyacids (HPAs) deposited on a graphite surface was carried out by scanning tunneling microscopy (STM) and tunneling spectroscopy (TS). Pure H 3 PW 12 O 40 and H 6 P 2 W 18 O 62 formed self-as…
Abstract End‐group modified hyperbranched polyetherimides were prepared by a one‐pot, two‐step reaction sequence. General synthetic techniques were developed to prepare both monofunctional terminating segments and the corresponding modified polyetherimide hyperbranched polymers. Monofunctional groups were used to term…
In the Gram-positive bacterium Bacillus subtilis the concentration of the amino acid L-arginine is controlled by the transcriptional regulator AhrC. The hexameric AhrC protein binds in an L-arginine-dependent manner to pseudo-palindromic operators within the promoter regions of arginine biosynthetic and catabolic gene…
We develop a theory to describe the reorientation phenomena in the lamellar phase of block copolymer melts under reciprocating shear flow. We show that, similar to the steady shear, the oscillating flow anisotropically suppresses fluctuations and gives rise to the [parallel]--> [perpendicular] transition. The experime…
Langmuir−Blodgett (LB) films of dilithium octacyanophthalocyanine [Li 2 Pc(CN) 8 ] were first prepared, and their electrochemical reduction/reoxidation behaviors were studied in detail. An overwhelming majority of the Li 2 Pc(CN) 8 molecules in the LB film were stacked in a face-to-face aggregated state and stood obli…
A solvent-free method for preparing electrically conductive polyurethane foams and elastomeric films is described. The method consists of impregnation of the oxidant into the foam through the sublimation of iodine, followed by in situ polymerization of pyrrole using pyrrole vapors to obtain a polypyrrole/polyurethane…
Surface functionalization of low-density polyethylene (LDPE), silanized glass, and free-standing polyaniline (PANI) films via UV-induced graft copolymerization with 1,1‘-bis(4-vinyl-benzyl)-4,4‘-bipyridinium dichloride (VBV) was carried out. The vinyl group containing viologen was synthesized by the double Anderson re…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTStructural Investigation of Ag−Pd Clusters Synthesized with the Radiolysis MethodCarmen M. Doudna, Massimo F. Bertino, and Akira T. TokuhiroView Author Information Department of Physics, University of MissouriRolla, Rolla, Missouri 65409, and Department of Nuclear Engineering,…
An initial photophysical study of a tetra-solketal-substituted zinc phthalocyanine is reported; at low temperature this compound exhibits very strong aggregation, and a new red shifted emission peak is observed, lambda max approximately 750 nm, attributed to a fluorescent phthalocyanine dimer.
The electronic conductivity of the Dion−Jacobson-type layered perovskite NaCa 2 Nb 3 O 10 was determined by employing ac impedance measurements using ion-blocking electrodes, electron-blocking electrodes, and dc Hebb−Wagner polarization measurements using NaCoO 2 as the reversible reference electrode. Oxygen partial-p…
The determination of the three-dimensional structures of biological macromolecules by X-ray diffraction generally requires large good-quality crystals, which are often difficult to obtain as crystal nucleation and growth depend upon a great number of physicochemical parameters. In the future, the emergence of structur…
Carbonaceous mesophases are discotic nematic liquid crystals that are spun into high performance carbon fibers using the melt spinning process. The spinning process produces a wide range of different fiber textures. Planar polar (PP) and planar radial (PR) textures are two ubiquitous ones. This paper presents theory a…
Layered Ni,Zn hydroxyacetates have been prepared by hydrothermal methods and have been used for anion exchange of the original acetate anions by chloride, bromide, carbonate, nitrate, sulfate, and phosphate. Exchange was complete in all cases. The solids have been characterised by elemental chemical analysis, powder X…