Materials Literature
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Nitrogen-doped carbon nanotubes have been synthesized using pyrolysis and characterized by scanning tunneling spectroscopy and transmission electron microscopy. The doped nanotubes are all metallic and exhibit strong electron donor states near the Fermi level. Using tight-binding and ab initio calculations, we observe…
Results of first-principles electronic structure calculations on the low-temperature monoclinic phase of the ferromagnetic perovskite BiMnO 3 [Atou et al. J. Solid State Chem . 1999, 145, 639] are presented. In agreement with experiments, the calculations obtain an insulating ferromagnetic ground state for this materi…
The thermal stability of organically modified layered silicate (OLS) plays a key role in the synthesis and processing of polymer-layered silicate (PLS) nanocomposites. The nonoxidative thermal degradation of montmorillonite and alkyl quaternary ammonium-modified montmorillonite were examined using conventional and hig…
We have studied the transport properties of a cholesteric liquid crystal by molecular dynamics simulation. The molecules consist of six soft ellipsoids of revolution, the axes of which are perpendicular to the line connecting their centres of symmetry. The angle between the symmetry axes of two adjacent ellipsoids is…
In this communication we report initial results of studies on x-ray and VUV excited luminescence of YAP and YAG crystals activated with Pr<SUP>3+</SUP> and YAP activated with Ce<SUP>3+</SUP>. Excitation and luminescence spectra of Pr<SUP>3+</SUP> and Ce<SUP>3+</SUP> d-f and Pr<SUP>3+</SUP> f-f emissions and luminescen…
Abstract A series of fully aromatic copolyesters based on p ‐acetoxybenzoic acid ( p ‐ABA), hydroquinone diacetate (HQDA), terephthalic acid (TPA), and m ‐acetoxybenzoic acid ( m ‐ABA) were prepared by a modified melt‐polycondensation reaction. The copolyesters were characterized by DSC, thermogravimetric analysis, 1…
Aproaches for imparting antimicrobial activity to polymeric materials have evolved from ancient practices to eclectic, modern strategies. The mechanisms by which microbes attach to polymeric surfaces and acquire resistance to antimicrobial agents are critically reviewed. Representative microorganisms (primarily bacter…
Abstract The charge distribution in samples under direct current electrical field was measured by the pulsed electro‐acoustic method, which showed that the space charges were greatly decreased and field distribution tended to be uniform in low‐density polyethylene (LDPE) by adding 0.3 wt % bis‐( p ‐ethylbenzylidene)so…
The two photon absorption coefficient and third order nonlinear optical susceptibility of ZnSe crystals were investigated using the transmission and degenerate four wave mixing methods. The experimental results show that imaginary part of third order nonlinear optical susceptibility decrease with increase of free carr…
Abstract A novel hyperbranched poly(glycidol) (HPG) was prepared and characterized. The synthesized HPG was used as a substrate of a polymer electrolyte. The ionic conductivity of a blend of HPG, polyurethane (PU), and salt was studied. The ionic conductivity of HPG/PU/LiClO 4 was about 6.6 × 10 −6 S · cm −1 at 20 °C…
Polymer-modified electrodes were obtained by spin-coating solutions of poly(benzobisimidazobenzophenanthroline) ladder (BBL) and semiladder (BBB) polymers on indium−tin oxide electrodes. An electrochemical study of these films showed reproducible and stable cyclic voltammograms for reduction of the polymer (in the abs…
Porous thin films with unique microstructures have been fabricated with the glancing angle deposition technique. This technique utilizes highly oblique deposition angles to make use of initial growth and shadowing conditions, which allow thin films consisting of microsprings and arrays of microcantilevers to be engine…
Cobalt(II) has been utilized as an external paramagnetic (1)H NMR probe for the study of the structure of dendrimers that possess specifically located metal recognition sites. The hyperfine-shifted (1)H NMR signals of the Co(II) complexes of several 2,6-diamidopyridine-containing dendrimers have been fully assigned by…
Abstract Polypropylene (PP) was blended with a linear low‐density polyethylene (LLDPE, containing 5% hexene comonomer) over a composition range of 10–90% of PP. The crystallization and morphology of the PP–LLDPE blends were studied by differential scanning calorimetry (DSC), polarized optical microscopy with a hot sta…
X-ray reflectivity, cyclic voltammetry, and scanning tunneling microscopy (STM) are used to examine the structure of alpha-SiW12O4(4-) or silicotungstic acid (STA) adsorbed on Ag(100) in acid solution. The voltammetry shows that STA passivates the Ag surface relative to electron transfer to a solution redox species. S…
Photolabile 6-nitrobenzo[a]pyrene (6-nitroBaP) released nitric oxide (NO) under visible-light irradiation. The generation of NO and the concomitant formation of the 6-oxyBaP radical were confirmed by ESR. BaP quinones were also detected as further oxidized products of the 6-oxyBaP radical. No such photodegradation was…
This paper reports the results of an investigation of vapor molecule sorption at different types of nanostructured nanoparticle films. Core-shell nanoparticles of two different core sizes, AU2-nm and Au5-nm, and molecular linkers of two different binding properties, 1,9-nonanedithiol and 11-mercaptoundecanoic acid, ar…
The fabrication of ZnSe/ZnTe superlattices grown by the process of rotating the substrate in the presence of an inhomogeneous flux distribution instead of successively closing and opening of source shutters is studied via Monte Carlo simulations. It is found that the concentration of each compound is sinusoidally modu…
A ring-locked, phenyltetraene-based, second-order nonlinear optical chromophore (CLD-1) was synthesized. It shows no drop in decomposition temperature compared to its phenyltriene analogue, while the molecular nonlinearity increases by a factor of 2.25 from 6252 × 10 - 48 to 14065 × 10 - 48 esu at 1.9 μm. Thin films a…
A purification method is given for extracting the Fe metal catalyst and non-SWNT carbon from nanotubes produced by the HiPco process.(1,2) A multistage purification method has been investigated. Sample purity is documented by ESEM, TEM, TGA, Raman and UV-vis-near-IR spectroscopy. Metal catalyzed oxidation at low tempe…