Materials Literature
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The behavior of the O 2 | HO 2 − redox couple at equilibrium on a commercial uncatalyzed carbon-polytetrafluoroethylene (PTFE) oxygen-diffusion electrode, fed with O 2 partial pressures between 0.21 and 1.0 atm, has been studied by electrochemical impedance spectroscopy. Measurements have been made in the open-circuit…
Reducing thickness of thin ferroelectric films typically comes with an apparent degradation of their dielectric and ferroelectric properties. In practice one observes a marked decrease of the linear dielectric constant and of remanent and maximum polarizations which may arise from the presence of passive layers at the…
Four-probe dc measurements were conducted on a polycrystalline material of composition which showed that the conductivity changed linearly with time during the initial stages when the atmosphere was changed from dry air to wet air, or vice versa. In order to analyze this transient conductivity change with time, a mode…
Symmetrical and unsymmetrical benzophenone Schiff bases of bifurcated dipeptides [e.g., Ar2C=N-CHR1- CONH-HNCO-CHR2-N=CAr2] have been synthesized using Boc methodology. These ligands may be regarded as chiral porphyrin mimics because of the alpha-carbons of the amino acids. The Schiff bases function as effective ligan…
Band structure of the metallic (n,n) carbon nanotubes (coefficients n are the indices of the two-dimensional primitive lattice vectors of the graphene lattice) is calculated in terms of a linear augmented cylindrical wave method. The results are used to correlate the minimum direct energy gaps E11 between the conducti…
A procedure to compute analytical second derivatives of the dynamic first hyperpolarizability with respect to vibrational coordinates has been developed and implemented at the time-dependent Hartree-Fock level. Simplifications are obtained by the same techniques as those employed to derive the 2n+1 rule and the interc…
Magnetic-field (B=0–1.5 T) dependent thermoelectric power (TEP) of the Na-doped La0.7Ca0.3−yNayMnO3 (0.0⩽y⩽0.3) system has been studied in the temperature range 80–300 K. X-ray diffraction studies indicate a rhombohedrally distorted perovskite structure of the samples. The observed sharp peak in the resistivity (ρ) ve…
The formation of the collapsed carbon nanotubes (CNTs) in a chemical vapor deposition process is studied by intentionally adding some toxic materials (sodium carbonate, sodium phosphate, and calcium chloride) of the catalyst into the CNTs growth system. The distorted CNTs and fully collapsed CNTs are observed as compa…
We describe a simple method and device design that enables fast in-plane electro-optic modulation in conventional nematic liquid crystal (NLC) devices. When combined with optimized NLC materials, this approach yields rotational speeds of 1°/μs (independent of rotation angle, over a wide range) at a moderately low volt…
ADVERTISEMENT RETURN TO ISSUEPREVCommunication to the...Communication to the EditorNEXTOrdered Conducting Polypyrrole Doped with Sulfopropyl Ether of β-CyclodextrinWei Chen, Xiaobo Wan, Ning Xu, and Gi XueView Author Information Department of Polymer Science, State Key Laboratory of Coordination Chemistry, Nanjing Uni…
A novel method for estimating the refractive index and density of vacuum-deposited molecular glasses was invented. It is based on the analysis of the interference of the light transmitted through film samples. Molar volumes of toluene, ethylbenzene, and propylbenzene in the glass states were thus elucidated. The volum…
The self-diffusivities of high molecular weight polystyrene chains in CO 2 -swollen polystyrene matrices were measured in real time using neutron reflectivity. Bilayer films of hydrogenated and deuterated polystyrene (PS) were prepared on silicon substrates and exposed to compressed CO 2 . The broadening of the interf…
Green-emitting Zn 2 SiO 4 : Mn phosphor particles having a spherical shape, high brightness, and short decay time were prepared by large-scale spray pyrolysis. The morphological control was attempted by using artificial colloidal solution obtained by adding the fumed silica particles to the aqueous solution. The parti…
Grafting a 4-fold alumina multilayer inside the nanotubes of a wide-pore MCM-41 material, by consecutive reactions with Al(O -sec -Bu) 3 followed by hydrolysis−calcination, changes the surface chemical functionality of the material from silica to alumina. This procedure leads to partial filling of the MCM-41 mesopores…
We study the morphology of asymmetric A8B48A8 triblock copolymer thin films confined between two homogeneous surfaces (walls). Morphology is investigated as a function of the film thickness and the strength of the wall–polymer interaction. For very thin films we observe cylinders perpendicular to the walls for a wide…
The reaction of sodium nitrite with sodium dithionite was studied in the presence of cobalt(II) tetrasulfophthalocyanine, COII(TSPc)4-, in aqueous alkaline solution. The overall mechanism comprises the reduction of CoII(TSPc)4- by dithionite, followed by the formation of an intermediate complex between COI(TSPc)5- and…
Electrochemical polymerization of aniline onto a gold electrode surface in an aqueous electrolyte solution containing a small amount of polyelectrolyte, i.e. , sodium poly(styrenesulfonate) (Na-PSS), and the characterization of the resulting polyaniline (PAn)/poly(styrenesulfonate) (PSS) composite have been studied us…
Optical absorption of silver nanoparticles dispersed within pores of monolithic mesoporous silica was investigated after annealing in different atmospheres. It has been found that treatment in H2 or N2 induces a strong surface plasmon resonance (SPR) as usually expected, but air annealing results in the disappearance…
It is known that the organic disulfides reductively cleave to corresponding two thiols and oxidatively recombine to parent disulfides by appropriate conditions. Therefore, we examined the applications of organic disulfides as electrode active materials for the lithium batteries. Dibenzo[ c , e ][1,2]dithiin ( 2 ), nap…
In the preceding publication, we showed that the hyperbranched polystyrenes (HBPS) synthesized as part of this study may be viewed as starlike molecules with a high branch density, which are either unentangled or weakly entangled. In this paper, the role of architecture, especially the branch density, on the rheologic…