Materials Literature
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Abstract A new and highly reproducible method to obtain mesostructured titania materials is introduced in this contribution. The mesostructured titania is obtained by employing self‐assembled structures of non‐ionic alkyl‐poly(ethylene oxide) surfactants as templates. The materials are produced without additional solv…
We numerically analyze the scaling behavior of experimentally accessible dynamical relaxation forms for networks modeled through finite Sierpinski-type lattices. Previous work has established unequivocally for such lattices that in the Rouse picture both the mechanical and the dielectric relaxation forms scale in freq…
The effects of confinement on the director field configurations are studied for a spherical particle immersed in a nematic liquid crystal. The liquid crystal is confined in a cylindrical geometry and the particle is located on the axis of symmetry. A finite element method is used to minimize the Frank free energy for…
Bi 3.25 La 0.75 Ti 3 O 12 (BLT) thin films were grown on Pt/Ti/SiO2/Si and on LaNiO3 (LNO) buffered Pt/Ti/SiO2/Si substrates using sol-gel processing. Scanning electron micrographs showed the BLT films are composed of peg-like or platelet-like grains depending upon annealing temperature and the substrate type. Large p…
Hollow spheres of mesostructured lead titanate, denoted as PTM-1, have been prepared via a combined oil-in-water emulsion mediated and neutral amine supermolecular templated route. The variety of reaction temperatures and KOH concentrations indicates hollow spheres can be formed under a very critical condition. The st…
3,3'-Dimethoxy-2,2'-bipyrrole (1) and 4,4'-dimethoxy-2,2'-bipyrrole (2) were obtained in short sequences and good yields from N-benzyl-3-hydroxypyrrole-2,4-dicarboxylic acid. The key intermediate leading to 1 is an N-benzyl-3-methoxypyrrole, which is dimerized by lithiation and oxidation with NiCl(2). The formation of…
Due to its large surface area and strongly attractive potential, a bundle of carbon nanotubes is an ideal substrate material for gas storage. In addition, adsorption in nanotubes can be exploited in order to separate the components of a mixture. In this paper, we investigate the preferential adsorption of ${\mathrm{D}…
Temperature dependent optical spectra are reported for $\ensuremath{\beta}\mathrm{\text{\ensuremath{-}}}{\mathrm{N}\mathrm{a}}_{0.33}{\mathrm{V}}_{2}{\mathrm{O}}_{5}$. The sodium ordering transition at ${T}_{\mathrm{N}\mathrm{a}}=240\text{ }\text{ }\mathrm{K}$ and, in particular, the charge ordering transition at ${T}…
Colloidal ZnSe nanocrystals are coated with a ZnS shell and are investigated by means of time-resolved photoluminescence spectroscopy. These nanocrystals are stable against photooxidation and have photoluminescence quantum efficiencies around 15% even months after the synthesis. Recombination processes are investigate…
Preferentially oriented perovskite-structured Na0.5K0.5NbO3 (NKN) thin films have been deposited on hexagonal Al2O3(011_2) substrates using rf magnetron sputtering of a stoichiometric, high-density, ceramic target. Structural and film surface properties were measured using x-ray diffraction and atomic force microscopy…
A new procedure to directly pattern a luminescent porous silicon substrate by dry‐removal soft lithography is outlined. The ability to transfer a removed microstructure of porous silicon to a free‐standing flexible polymer film is also demonstrated, and by removing strips in orthogonal directions, an array of PSi pill…
The microstructure of distributed electron cyclotron resonance plasma-deposited hydrogenated amorphous carbon films (a-C:H) was investigated using electron diffraction, Raman spectroscopy, and Fourier transform infrared spectroscopy. Experimental evidence of the existence of transpolyacetylene (TPA) chains in a-C:H fi…
The hydrothermal reaction of V2O5, H2C2O4·2H2O, en, KOH and NiCl2·6H2O gives a new two-dimensional open-framework solid; the extended structure consists of a two-dimensional network formed by the interconnection of each [V18O42Cl] cage to four other neighboring units via six [Ni(en)2]2+ bridging groups.
Laterally aligned carbon nanotubes were synthesized on substrates over iron nanoparticles using chemical vapor deposition. In addition, aligned carbon nanotubes grown vertically and with tilt angle to the substrates were produced, which means that it is possible to grow aligned carbon nanotubes at any angle relative t…
Mesoporous hybrid inorganic–organic silicate films with pendant methyl groups are prepared. With a high organic fraction, these films are hydrophobic, which is important in the fabrication of low‐k dielectrics. The refractive index of layers with smaller organic fraction can be switched reversibly over a large refract…
A promising solution to the environmental instability of semiconducting organic materials is presented. Thin, highly ordered films (see Figure, a scanning probe microscopy image), fibers, and field‐effect transistors (FETs), comprising chain‐structures based on the so‐called Magnus’ green salt, [Pt(NH 3 ) 4 ]‐[PtCl 4…
Uniform, separated BaCrO 4 single‐crystalline nanofibers with high aspect ratio (> 5000, see Figure) can be fabricated at room temperature in aqueous solution using a double hydrophilic block copolymer as structure‐directing agent and introducing colloidal nucleation agents. Such fibers represent a model case for a…
ADVERTISEMENT RETURN TO ISSUEPREVNoteNEXTAn Improved Method To Strip Aluminum from Porous Anodic Alumina FilmsTerry T. Xu, Richard D. Piner, and Rodney S. RuoffView Author Information Department of Mechanical Engineering, Northwestern University, 2145 Sheridan Road, Evanston, Illinois 60208 Cite this: Langmuir 2003, 1…
We conducted impedance spectroscopy measurements on lead zirconate titanate capacitors of varying lateral size from 130×180 μm down to 1×1 μm. We discovered a peak in the impedance response with a frequency that depends on the perimeter of the capacitor with an exponential relationship. Our model for this effect is ba…
We provide existence of a unique smooth solution for a class of one-and two-phase Stefan problems with Gibbs-Thomson correction in arbitrary space dimensions.In addition, it is shown that the moving interface depends analytically on the temporal and spatial variables.Of crucial importance for the analysis is the prope…